tag:blogger.com,1999:blog-5776200207093867422024-03-05T14:45:59.015-08:00AudioBlogV.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.comBlogger20125tag:blogger.com,1999:blog-577620020709386742.post-30773563085152129912013-08-13T20:49:00.003-07:002013-08-13T20:50:07.288-07:00Hornresp T-TQWT tutorialI've created a small screen cast that describes how to design a tapped - TQWT (aka, reverse tapped horn). Enjoy<br />
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<object class="BLOGGER-youtube-video" classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,40,0" data-thumbnail-src="http://i1.ytimg.com/vi/fjU__o5wEj8/0.jpg" height="266" width="320"><param name="movie" value="http://www.youtube.com/v/fjU__o5wEj8?version=3&f=user_uploads&c=google-webdrive-0&app=youtube_gdata" /><param name="bgcolor" value="#FFFFFF" /><param name="allowFullScreen" value="true" /><embed width="320" height="266" src="http://www.youtube.com/v/fjU__o5wEj8?version=3&f=user_uploads&c=google-webdrive-0&app=youtube_gdata" type="application/x-shockwave-flash" allowfullscreen="true"></embed></object></div>
<br />V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-45836642669890011962012-06-13T10:48:00.003-07:002012-06-13T10:48:40.779-07:00The Music SpectrumFrom <a href="http://www.independentrecording.net/irn/resources/freqchart/main_display.htm">http://www.independentrecording.net/irn/resources/freqchart/main_display.htm</a><br />
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<a href="http://www.independentrecording.net/irn/resources/freqchart/images/main_chart.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="http://www.independentrecording.net/irn/resources/freqchart/images/main_chart.jpg" width="288" /></a></div>
<br />V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-1149644345604130552011-01-22T19:37:00.000-08:002011-01-22T19:39:21.508-08:00BlogWorthy - Basic Audio e-book<a href="http://www.vias.org/crowhurstba/">Basic Audio By Norman CrowHurst</a><div><br /></div><div>This online book is actually written in plainspeak !!</div>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-74229305988662619482010-12-28T07:40:00.000-08:002010-12-28T07:41:22.213-08:00DIY OS waveguideI thought these posts / articles were "blogworthy" . Enjoy !!<div><br /><div><a href="http://www.diyaudio.com/forums/gedlee/122318-diy-waveguide-loudspeaker-kit-153.html">http://www.diyaudio.com/forums/gedlee/122318-diy-waveguide-loudspeaker-kit-153.html</a><br /><div><br /></div><div><a href="http://www.enjoythemusic.com/diy/1110/oblate_spheroid_waveguides.htm">http://www.enjoythemusic.com/diy/1110/oblate_spheroid_waveguides.htm</a></div></div></div>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-9650313904592664862009-06-05T13:55:00.000-07:002009-06-05T14:22:07.960-07:00Push Pull 2A3 tube amplifier complete<table style="width: auto;"><tbody><tr><td><a href="http://picasaweb.google.com/lh/photo/Bir0Q0BWTZU61tXEa0FRyQ?feat=embedwebsite"><img src="http://lh4.ggpht.com/_xgY0jtSX-KQ/R5zSrnLp-iI/AAAAAAAABDs/kAFsRg4jfsE/s144/chassismount.jpg" /></a></td></tr><tr><td style="font-family: arial,sans-serif; font-size: 11px; text-align: right;">From <a href="http://picasaweb.google.com/balamuru/2A3PushPullTubeAmplifier?feat=embedwebsite">2A3 Push Pull Tube Amplifier</a></td></tr></tbody></table><br /><br />After neglecting this project for over a year because of a variety of reasons, I finally got it working over the weekend. I addressed a couple of irritating initial issues namely:<br /><ul><li>Electrical hum due to a ground loop (shortened the ground return paths)</li><li>Mechanical hum in L1 of the LCLC power supply filter (replaced L1 (320 mH / 10 ohm Triad choke with a 10 ohm resistor resulting in an RCLC filter). Since the output stages is push pull, they can excelled common mode noise rejection and aren't bothered by what I simulated to be around 1V PP of hum. The input stage is quitened down by a rather severe RC stage dropping about 50 % of B+ (290V).</li></ul>I'll add a schematic later on, but the circuit itself is exceedingly simple: Single ended D3A (in triode mode) driving a rathe expensive (and luckily for me, free) Electra-Print SE:PP interstage transformer powering a push pull pair of 2A3 triodes in cathode bias . Output transformers were scavenged from a dead Fisher 800C receiver and I'm estimating output power in the 6W / class A range with some A2 capability (though I could probably get this circuit to run about 15 W class AB with some minor mods + fixed bias).<br /><br />No global feedback. Some minimal local feedback around the cathodes of the push pull pairs via 30uF capacitors (all I had at that moment). Bias is relatively conservative around -45 V and PK voltage of about 245V,<br /><br />Power supply capacitors are around 50uF ASC motor run capacitors. Still need to bypass them .<br /><br />Power transformer is a heavy duty low DCR (< 10 ohm) 240:110V transformer run backwards in step up mode.<br /><br />Sound: I'll let others decide, but I think it's fair to say that, unlike some of my other "endeavors", this has been a successful high end project.V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-87977889615622976572009-05-25T12:33:00.000-07:002009-05-25T12:35:00.067-07:00Calibration File for WM-61AY microphone capsuleDownload the data from <a href="http://www.holmacoustics.com/downloads/MicrophoneCalibration/Mic_WM61A.cal">http://www.holmacoustics.com/downloads/MicrophoneCalibration/Mic_WM61A.cal</a>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-20582915079203710752009-05-03T09:51:00.000-07:002009-05-03T09:52:18.731-07:00Test Your Hearing<a href="http://www.digital-recordings.com/hearing-test/www-ht-pro/ht_help_p.html">http://www.digital-recordings.com/hearing-test/www-ht-pro/ht_help_p.html</a>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-62424468672392705002009-04-06T18:16:00.000-07:002009-04-06T20:59:44.962-07:00TangBand Reverse Tapped Pipe<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSuXry64Vxe3J8Ajmw1CI2FZ3UawvpbKfd3jup6k8iihSYqcHRQkT6YWLaXN7z_e1MGJnPfsX4kR-B0C4zqdoTd8H4E1v3GolKxFlOzNMsGGbhyphenhyphenvM5qBI1ULwJ0uDg-1EVXJ-8Xl52bEY/s1600-h/tb_xray.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 400px; height: 216px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSuXry64Vxe3J8Ajmw1CI2FZ3UawvpbKfd3jup6k8iihSYqcHRQkT6YWLaXN7z_e1MGJnPfsX4kR-B0C4zqdoTd8H4E1v3GolKxFlOzNMsGGbhyphenhyphenvM5qBI1ULwJ0uDg-1EVXJ-8Xl52bEY/s400/tb_xray.png" alt="" id="BLOGGER_PHOTO_ID_5321752838697638882" border="0" /></a><br />Or more commonly known as a reverse tapped horn, though that is really an oxymoron. In any case, I built a prototype of this on a lark using a single <span class="ProductTitle">Tang Band W69-1042J 6"x9" Subwoofer using 1/" MDF (yuck !!). I played around with stuffing and finally left it unstuffed. Despite being unstuffed, the bass is non-resonant ie. non boomy. Note that I did take the time to add side - to side braces (not shown in picture). Well, it isn't going to displace the big horn sub, as I can find the limits of its excursion IF I want to (somewhat above normal listening levels though) but it was a good cheap experiment. Excursion is lower than expected, for the amount of sound it produces, but as I said, I can find it's limits Iif I want. Probably solid to 30 - 35 Hz with output below that. Remember, this is a 6 x 9 87db.w/m 8 ohm driver keeping up with a pair of 95 - 97+ db/w/m speakers (depending on what is currently hooked up) driven by a cheapo 100 W plate amp.<br /><br />I wonder what would happen if I took off driver access plate and allowed the driver to breathe through more than the small terminus that it's now exposed to . Food for thought ....<br /><br />Here are the input parameters and theoretical impedance curves.<br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhc0ipoIcAXnWide2JnfU3kYAL945qi7MtrT4VyAgRCbzvaTAsVcWUPAUuTNn6w_vb4AaGMN56uPtbZnNbwM0N2tjNDuu2zfMp_DJLOk4Bs7apX4Ilu-cii0rW1VbK-dStv8IvdUJ8Q0cI/s1600-h/hr.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 214px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhc0ipoIcAXnWide2JnfU3kYAL945qi7MtrT4VyAgRCbzvaTAsVcWUPAUuTNn6w_vb4AaGMN56uPtbZnNbwM0N2tjNDuu2zfMp_DJLOk4Bs7apX4Ilu-cii0rW1VbK-dStv8IvdUJ8Q0cI/s320/hr.png" alt="" id="BLOGGER_PHOTO_ID_5321753905652781362" border="0" /></a><span class="ProductTitle"><br />Lastly, here are the observed impedance curves. Close but the 2nd impedance peak is off, probably due to differences caused buy the (inevitable) folding.<br /><br /></span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbNFZVONHBzTT1fhhHP8A0wklvuOpI98aznpaFrs4FbWSPF1bxqfdCJaNpvCp2aln6o7ePINszQ24ir8kOhAEHTtSV1jzgU-7tgJ6Kiy-J6yEpYrOozCDmaKxxh2WUAXJBCFOeQQvbJXY/s1600-h/th_sealedup.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 320px; height: 218px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbNFZVONHBzTT1fhhHP8A0wklvuOpI98aznpaFrs4FbWSPF1bxqfdCJaNpvCp2aln6o7ePINszQ24ir8kOhAEHTtSV1jzgU-7tgJ6Kiy-J6yEpYrOozCDmaKxxh2WUAXJBCFOeQQvbJXY/s320/th_sealedup.png" alt="" id="BLOGGER_PHOTO_ID_5321755188399132658" border="0" /></a><br /><span class="ProductTitle"><br /><br /><br /><br /><br /></span>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-10782142850572334622008-12-20T20:38:00.000-08:002008-12-20T20:52:31.428-08:00Stephens Trusonic 206-AXA 15" co-axial Crossover, Impedance Measurements, T/S measurementsThe crossover is a relatively simple affair: The woofer runs full range and the tweeter is a 2nd order (in reverse phase) consisting of something about 10 - 12uF cap (can't make out the exact value since it is encased in resin) and a 2mH inductor. I reverse engineered the values by isolating the components and measuring the L and C values using ARTA. Note that the tweeter is nominally 8 ohm in the 1 - 2KHz range<br /><br /><div style="text-align: left;">Woofer Impedance Graph<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKhY0eX0b9lnT8_75X4zmjc_CRDcbe0HxRsy1BLcpqW6qseJLNYGPUphHnCYeO6NWGdHfPWLQ-lt-ggB7Va1uyLF8iYwVOY6qoc6s1BL3Id0CBPC-C9y8n4BNWs7BrKxN0LmwA-ksUwNI/s1600-h/206AXA-WOOFER-IMP.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 320px; height: 240px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKhY0eX0b9lnT8_75X4zmjc_CRDcbe0HxRsy1BLcpqW6qseJLNYGPUphHnCYeO6NWGdHfPWLQ-lt-ggB7Va1uyLF8iYwVOY6qoc6s1BL3Id0CBPC-C9y8n4BNWs7BrKxN0LmwA-ksUwNI/s320/206AXA-WOOFER-IMP.png" alt="" id="BLOGGER_PHOTO_ID_5282099770958710706" border="0" /></a><br /></div><br />Tweeter + Horn Impedance graph<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrVsau3JfZqLfvCiuwDFlTE8v-d5GAR1eeCXTiOZFDO8RyU7Hp-UUz1oEjsZS8cU6GRzVlsIDG-krFBKfdtRFA02w8iR7Lx7N0GoNhgM-6YUFD6fJqqKeK3m0VbwrB9JNdB4UGgn1zOQQ/s1600-h/206AXA-TWEETER+HORN-IMP.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 320px; height: 240px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrVsau3JfZqLfvCiuwDFlTE8v-d5GAR1eeCXTiOZFDO8RyU7Hp-UUz1oEjsZS8cU6GRzVlsIDG-krFBKfdtRFA02w8iR7Lx7N0GoNhgM-6YUFD6fJqqKeK3m0VbwrB9JNdB4UGgn1zOQQ/s320/206AXA-TWEETER+HORN-IMP.png" alt="" id="BLOGGER_PHOTO_ID_5282099618975794162" border="0" /></a><br /><span><br /><br /><br /></span><span style="font-weight: bold;">Compression Tweeter + Multicell Horn<br /></span><span style="font-weight: bold;"><br /></span><pre><br /><br />* This data was exported from the Dayton Audio WT3 Woofer Tester<br />*<br />* Manufacturer:<br />* Model:<br />D 0.0 [mm]<br />Re 7.30 [Ohms]<br />Fs 637.20 [Hz]<br />Zm 7.69 [Ohms]<br />BL 0.00 [N/A]<br />Qms 0.031<br />Qes 0.576<br />Qts 0.029<br />Vas 0.000 [liters]<br />L10k 0.12 [mH]<br />n0 0.00 [%]<br />dBSPL 0.00 [1W/1m]<br />Ms 0.00 [grams]<br />Cms 0.00 [mm/N]<br />*<br />*<br />Freq Impedance Phase<br />1.029 7.301 -0.160<br />1.059 7.301 -0.160<br />1.091 7.301 -0.160<br />1.122 7.301 -0.160<br />1.155 7.301 -0.160<br />1.189 7.301 -0.160<br />1.224 7.301 -0.160<br />1.260 7.301 -0.160<br />1.297 7.301 -0.160<br />1.335 7.301 -0.185<br />1.374 7.301 -0.185<br />1.414 7.301 -0.185<br />1.456 7.301 -0.185<br />1.498 7.301 -0.185<br />1.542 7.301 -0.185<br />1.587 7.301 -0.185<br />1.634 7.301 -0.185<br />1.682 7.301 -0.185<br />1.731 7.301 -0.185<br />1.782 7.301 -0.185<br />1.834 7.301 -0.185<br />1.888 7.301 -0.185<br />1.943 7.301 -0.185<br />2.000 7.302 -0.199<br />2.059 7.302 -0.199<br />2.119 7.302 -0.199<br />2.181 7.302 -0.199<br />2.245 7.302 -0.199<br />2.311 7.302 -0.199<br />2.378 7.302 -0.199<br />2.448 7.302 -0.199<br />2.520 7.302 -0.199<br />2.594 7.302 -0.199<br />2.670 7.326 -0.012<br />2.748 7.326 -0.012<br />2.828 7.326 -0.012<br />2.911 7.326 -0.012<br />2.997 7.326 -0.012<br />3.084 7.326 -0.012<br />3.175 7.326 -0.012<br />3.268 7.326 -0.012<br />3.364 7.315 0.063<br />3.462 7.315 0.063<br />3.564 7.315 0.063<br />3.668 7.315 0.063<br />3.775 7.315 0.063<br />3.886 7.315 0.063<br />4.000 7.312 0.051<br />4.117 7.312 0.051<br />4.238 7.312 0.051<br />4.362 7.312 0.051<br />4.490 7.312 0.051<br />4.621 7.312 0.051<br />4.757 7.300 -0.041<br />4.896 7.300 -0.041<br />5.040 7.300 -0.041<br />5.187 7.300 -0.041<br />5.339 7.299 -0.019<br />5.496 7.299 -0.019<br />5.657 7.299 -0.019<br />5.823 7.299 -0.019<br />5.993 7.291 0.050<br />6.169 7.291 0.050<br />6.350 7.291 0.050<br />6.536 7.291 0.050<br />6.727 7.300 0.223<br />6.924 7.300 0.223<br />7.127 7.300 0.223<br />7.336 7.295 0.195<br />7.551 7.295 0.195<br />7.772 7.295 0.195<br />8.000 7.298 0.189<br />8.234 7.298 0.189<br />8.476 7.298 0.189<br />8.724 7.300 0.177<br />8.980 7.300 0.177<br />9.243 7.300 0.177<br />9.514 7.311 0.186<br />9.792 7.311 0.186<br />10.079 7.289 0.227<br />10.375 7.289 0.227<br />10.679 7.292 0.236<br />10.992 7.292 0.236<br />11.314 7.283 0.287<br />11.645 7.283 0.287<br />11.986 7.306 0.283<br />12.338 7.306 0.283<br />12.699 7.301 0.293<br />13.071 7.301 0.293<br />13.454 7.302 0.279<br />13.849 7.302 0.279<br />14.254 7.305 0.233<br />14.672 7.307 0.215<br />15.102 7.307 0.215<br />15.545 7.289 0.252<br />16.000 7.288 0.275<br />16.469 7.288 0.275<br />16.951 7.289 0.342<br />17.448 7.305 0.345<br />17.959 7.302 0.354<br />18.486 7.302 0.354<br />19.027 7.306 0.326<br />19.585 7.309 0.258<br />20.159 7.302 0.235<br />20.749 7.306 0.248<br />21.357 7.303 0.264<br />21.983 7.301 0.288<br />22.627 7.300 0.305<br />23.290 7.306 0.363<br />23.973 7.305 0.378<br />24.675 7.310 0.376<br />25.398 7.313 0.345<br />26.143 7.313 0.380<br />26.909 7.313 0.370<br />27.697 7.313 0.349<br />28.509 7.313 0.358<br />29.344 7.313 0.386<br />30.204 7.314 0.411<br />31.089 7.317 0.456<br />32.000 7.314 0.474<br />32.938 7.318 0.499<br />33.903 7.318 0.513<br />34.896 7.318 0.514<br />35.919 7.314 0.538<br />36.971 7.313 0.530<br />38.055 7.312 0.567<br />39.170 7.313 0.596<br />40.317 7.314 0.599<br />41.499 7.314 0.606<br />42.715 7.315 0.593<br />43.967 7.315 0.610<br />45.255 7.317 0.619<br />46.581 7.317 0.646<br />47.946 7.312 0.664<br />49.351 7.311 0.690<br />50.797 7.310 0.714<br />52.285 7.315 0.732<br />53.817 7.320 0.754<br />55.394 7.324 0.792<br />57.018 7.323 0.803<br />58.688 7.325 0.815<br />60.408 7.320 0.822<br />62.178 7.320 0.851<br />64.000 7.318 0.875<br />65.875 7.321 0.900<br />67.806 7.322 0.899<br />69.792 7.323 0.918<br />71.838 7.321 0.940<br />73.943 7.322 0.984<br />76.109 7.321 1.034<br />78.339 7.322 1.092<br />80.635 7.324 1.127<br />82.998 7.325 1.147<br />85.430 7.326 1.157<br />87.933 7.327 1.189<br />90.510 7.328 1.207<br />93.162 7.329 1.229<br />95.892 7.331 1.259<br />98.701 7.333 1.316<br />101.594 7.334 1.372<br />104.571 7.333 1.410<br />107.635 7.334 1.417<br />110.789 7.334 1.432<br />114.035 7.335 1.461<br />117.377 7.336 1.517<br />120.816 7.340 1.571<br />124.356 7.341 1.633<br />128.000 7.341 1.676<br />131.751 7.340 1.710<br />135.611 7.341 1.755<br />139.585 7.344 1.793<br />143.675 7.346 1.852<br />147.885 7.346 1.906<br />152.219 7.345 1.958<br />156.679 7.344 1.996<br />161.270 7.347 2.042<br />165.995 7.349 2.104<br />170.860 7.352 2.167<br />175.866 7.352 2.218<br />181.019 7.353 2.260<br />186.324 7.356 2.329<br />191.783 7.358 2.416<br />197.403 7.358 2.483<br />203.187 7.360 2.532<br />209.141 7.364 2.604<br />215.269 7.366 2.684<br />221.577 7.366 2.753<br />228.070 7.368 2.810<br />234.753 7.371 2.891<br />241.632 7.372 2.970<br />248.712 7.373 3.042<br />256.000 7.378 3.124<br />263.501 7.381 3.224<br />271.223 7.383 3.315<br />279.170 7.386 3.404<br />287.350 7.388 3.503<br />295.770 7.390 3.588<br />304.437 7.394 3.681<br />313.358 7.397 3.784<br />322.540 7.400 3.887<br />331.991 7.404 3.994<br />341.719 7.408 4.101<br />351.732 7.412 4.220<br />362.039 7.416 4.337<br />372.647 7.420 4.460<br />383.567 7.425 4.584<br />394.806 7.428 4.716<br />406.375 7.434 4.851<br />418.282 7.438 4.987<br />430.539 7.444 5.135<br />443.155 7.450 5.283<br />456.140 7.457 5.430<br />469.506 7.462 5.579<br />483.264 7.469 5.753<br />497.424 7.477 5.927<br />512.000 7.486 6.115<br />527.003 7.498 6.324<br />542.445 7.511 6.541<br />558.340 7.527 6.771<br />574.701 7.551 7.015<br />591.541 7.586 7.238<br />608.874 7.636 7.335<br />626.715 7.680 7.178<br />645.080 7.684 6.896<br />663.982 7.648 6.806<br />683.438 7.610 7.004<br />703.464 7.593 7.322<br />724.077 7.591 7.652<br />745.294 7.596 7.970<br />767.133 7.605 8.281<br />789.612 7.617 8.595<br />812.749 7.630 8.914<br />836.565 7.646 9.239<br />861.078 7.664 9.572<br />886.309 7.684 9.919<br />912.280 7.707 10.285<br />939.012 7.735 10.673<br />966.527 7.770 11.086<br />994.849 7.814 11.517<br />1024.000 7.873 11.947<br />1054.005 7.956 12.298<br />1084.890 8.052 12.400<br />1116.680 8.125 12.220<br />1149.401 8.146 11.993<br />1183.081 8.133 11.979<br />1217.748 8.120 12.194<br />1253.431 8.118 12.530<br />1290.159 8.121 12.958<br />1327.964 8.131 13.507<br />1366.876 8.161 14.185<br />1406.929 8.219 14.889<br />1448.155 8.301 15.559<br />1490.589 8.401 16.179<br />1534.266 8.520 16.727<br />1579.224 8.655 17.201<br />1625.499 8.812 17.506<br />1673.129 8.953 17.585<br />1722.156 9.054 17.756<br />1772.619 9.169 18.439<br />1824.561 9.401 19.380<br />1878.024 9.796 20.026<br />1933.055 10.346 19.672<br />1989.697 10.918 17.696<br />2048.000 11.253 14.151<br />2108.011 11.141 10.356<br />2169.780 10.712 8.026<br />2233.360 10.249 7.522<br />2298.802 9.952 8.365<br />2366.162 9.899 9.858<br />2435.496 10.120 10.992<br />2506.862 10.497 10.675<br />2580.318 10.763 8.470<br />2655.927 10.605 5.629<br />2733.752 10.150 4.378<br />2813.857 9.784 4.840<br />2896.309 9.643 5.537<br />2981.178 9.579 6.237<br />3068.533 9.581 7.135<br />3158.448 9.655 7.497<br />3250.997 9.663 7.478<br />3346.259 9.692 7.227<br />3444.312 9.704 6.465<br />3545.238 9.574 5.344<br />3649.121 9.368 5.244<br />3756.049 9.226 5.963<br />3866.109 9.129 6.760<br />3979.395 9.049 7.466<br />4096.000 8.976 8.238<br />4216.022 8.926 9.142<br />4339.561 8.918 10.097<br />4466.720 8.943 10.892<br />4597.605 8.974 11.492<br />4732.325 8.976 11.985<br />4870.992 8.965 12.628<br />5013.723 8.972 13.435<br />5160.637 9.012 14.220<br />5311.855 9.063 14.914<br />5467.504 9.114 15.613<br />5627.714 9.189 16.383<br />5792.619 9.309 17.013<br />5962.355 9.434 17.192<br />6137.066 9.484 17.061<br />6316.896 9.455 17.114<br />6501.995 9.416 17.562<br />6692.518 9.416 18.281<br />6888.623 9.470 19.055<br />7090.476 9.571 19.639<br />7298.242 9.637 19.749<br />7512.097 9.624 20.057<br />7732.218 9.602 20.864<br />7958.790 9.672 21.776<br />8192.000 9.760 22.425<br />8432.044 9.830 22.965<br />8679.122 9.887 23.596<br />8933.439 9.960 24.349<br />9195.209 10.065 25.098<br />9464.649 10.196 25.771<br />9741.985 10.338 26.055<br />10027.447 10.412 26.375<br />10321.273 10.458 26.910<br />10623.710 10.567 27.646<br />10935.008 10.683 28.189<br />11255.428 10.792 28.740<br />11585.238 10.916 29.335<br />11924.711 11.056 29.842<br />12274.132 11.184 30.292<br />12633.791 11.312 30.782<br />13003.989 11.458 31.285<br />13385.035 11.609 31.680<br />13777.247 11.752 32.035<br />14180.951 11.884 32.387<br />14596.485 12.021 32.689<br />15024.194 12.130 33.065<br />15464.437 12.236 33.512<br />15917.579 12.371 34.090<br />16384.000 12.523 34.584<br />16864.088 12.674 35.037<br />17358.243 12.824 35.514<br />17866.879 12.982 35.980<br />18390.418 13.145 36.411<br />18929.299 13.294 36.880<br />19483.969 13.428 37.363<br />20054.893 13.420 37.904<br />20642.546 12.819 38.105<br /><br /></pre><br /><br /><br /><span style="font-weight: bold;">Woofer</span><br /><br /><pre><br />* This data was exported from the Dayton Audio WT3 Woofer Tester<br />*<br />* Manufacturer:<br />* Model:<br />D 317.5 [mm]<br />Re 9.44 [Ohms]<br />Fs 43.07 [Hz]<br />Zm 163.30 [Ohms]<br />BL 19.56 [N/A]<br />Qms 7.009<br />Qes 0.430<br />Qts 0.405<br />Vas 186.700 [liters]<br />L10k 0.89 [mH]<br />n0 3.31 [%]<br />dBSPL 97.30 [1W/1m]<br />Ms 64.39 [grams]<br />Cms 0.21 [mm/N]<br />*<br />*<br />Freq Impedance Phase<br />1.029 9.475 1.991<br />1.059 9.475 1.991<br />1.091 9.475 1.991<br />1.122 9.475 1.991<br />1.155 9.475 1.991<br />1.189 9.475 1.991<br />1.224 9.475 1.991<br />1.260 9.475 1.991<br />1.297 9.475 1.991<br />1.335 9.471 4.143<br />1.374 9.471 4.143<br />1.414 9.471 4.143<br />1.456 9.471 4.143<br />1.498 9.471 4.143<br />1.542 9.471 4.143<br />1.587 9.471 4.143<br />1.634 9.471 4.143<br />1.682 9.471 4.143<br />1.731 9.471 4.143<br />1.782 9.471 4.143<br />1.834 9.471 4.143<br />1.888 9.471 4.143<br />1.943 9.471 4.143<br />2.000 9.480 6.341<br />2.059 9.480 6.341<br />2.119 9.480 6.341<br />2.181 9.480 6.341<br />2.245 9.480 6.341<br />2.311 9.480 6.341<br />2.378 9.480 6.341<br />2.448 9.480 6.341<br />2.520 9.480 6.341<br />2.594 9.480 6.341<br />2.670 9.544 8.532<br />2.748 9.544 8.532<br />2.828 9.544 8.532<br />2.911 9.544 8.532<br />2.997 9.544 8.532<br />3.084 9.544 8.532<br />3.175 9.544 8.532<br />3.268 9.544 8.532<br />3.364 9.607 10.666<br />3.462 9.607 10.666<br />3.564 9.607 10.666<br />3.668 9.607 10.666<br />3.775 9.607 10.666<br />3.886 9.607 10.666<br />4.000 9.687 12.802<br />4.117 9.687 12.802<br />4.238 9.687 12.802<br />4.362 9.687 12.802<br />4.490 9.687 12.802<br />4.621 9.687 12.802<br />4.757 9.783 14.869<br />4.896 9.783 14.869<br />5.040 9.783 14.869<br />5.187 9.783 14.869<br />5.339 9.910 16.909<br />5.496 9.910 16.909<br />5.657 9.910 16.909<br />5.823 9.910 16.909<br />5.993 10.063 18.905<br />6.169 10.063 18.905<br />6.350 10.063 18.905<br />6.536 10.063 18.905<br />6.727 10.235 20.865<br />6.924 10.235 20.865<br />7.127 10.235 20.865<br />7.336 10.400 22.659<br />7.551 10.400 22.659<br />7.772 10.400 22.659<br />8.000 10.561 24.381<br />8.234 10.561 24.381<br />8.476 10.561 24.381<br />8.724 10.726 26.095<br />8.980 10.726 26.095<br />9.243 10.726 26.095<br />9.514 10.890 27.880<br />9.792 10.890 27.880<br />10.079 11.053 29.760<br />10.375 11.053 29.760<br />10.679 11.268 31.600<br />10.992 11.268 31.600<br />11.314 11.524 33.408<br />11.645 11.524 33.408<br />11.986 11.827 35.148<br />12.338 11.827 35.148<br />12.699 12.136 36.866<br />13.071 12.136 36.866<br />13.454 12.472 38.491<br />13.849 12.472 38.491<br />14.254 12.834 40.010<br />14.672 13.204 41.440<br />15.102 13.204 41.440<br />15.545 13.585 42.859<br />16.000 13.994 44.152<br />16.469 13.994 44.152<br />16.951 14.421 45.454<br />17.448 14.867 46.662<br />17.959 15.313 47.947<br />18.486 15.313 47.947<br />19.027 15.800 49.221<br />19.585 16.602 51.094<br />20.159 16.907 51.717<br />20.749 17.521 52.957<br />21.357 18.182 54.192<br />21.983 18.899 55.429<br />22.627 19.681 56.619<br />23.290 20.532 57.757<br />23.973 21.450 58.854<br />24.675 22.452 59.907<br />25.398 23.533 60.884<br />26.143 24.716 61.836<br />26.909 26.006 62.738<br />27.697 27.426 63.545<br />28.509 28.975 64.233<br />29.344 31.643 65.070<br />30.204 34.579 65.661<br />31.089 36.765 65.879<br />32.000 40.563 66.145<br />32.938 45.020 66.228<br />33.903 50.690 65.960<br />34.896 57.536 65.182<br />35.919 66.381 63.528<br />36.971 77.140 60.975<br />38.055 95.419 55.665<br />39.170 121.311 45.999<br />40.317 138.398 36.950<br />41.499 154.019 23.462<br />42.715 163.042 2.408<br />43.967 156.276 -18.701<br />45.255 136.178 -35.750<br />46.581 110.862 -47.000<br />47.946 89.861 -53.480<br />49.351 75.367 -57.249<br />50.797 65.121 -59.672<br />52.285 57.383 -61.231<br />53.817 49.948 -62.200<br />55.394 43.985 -62.361<br />57.018 40.177 -61.990<br />58.688 35.765 -60.921<br />60.408 32.866 -59.783<br />62.178 30.399 -58.605<br />64.000 28.394 -57.415<br />65.875 26.368 -56.109<br />67.806 24.688 -55.041<br />69.792 23.316 -54.278<br />71.838 22.196 -53.841<br />73.943 21.259 -53.521<br />76.109 20.404 -53.147<br />78.339 19.544 -52.469<br />80.635 18.918 -51.592<br />82.998 18.305 -50.280<br />85.430 17.749 -48.648<br />87.933 17.228 -46.798<br />90.510 16.649 -44.610<br />93.162 16.055 -42.548<br />95.892 15.394 -40.628<br />98.701 14.836 -39.219<br />101.594 14.316 -37.984<br />104.571 13.884 -36.907<br />107.635 13.585 -35.947<br />110.789 13.364 -34.829<br />114.035 13.205 -33.642<br />117.377 13.012 -32.181<br />120.816 12.810 -30.555<br />124.356 12.580 -28.790<br />128.000 12.391 -27.291<br />131.751 12.190 -25.832<br />135.611 12.004 -24.272<br />139.585 11.885 -23.018<br />143.675 11.780 -21.672<br />147.885 11.700 -20.306<br />152.219 11.618 -18.982<br />156.679 11.518 -17.767<br />161.270 11.408 -16.575<br />165.995 11.322 -15.158<br />170.860 11.263 -13.747<br />175.866 11.199 -12.319<br />181.019 11.142 -11.107<br />186.324 11.103 -9.811<br />191.783 11.085 -8.296<br />197.403 11.083 -6.929<br />203.187 11.094 -5.717<br />209.141 11.118 -4.482<br />215.269 11.133 -3.342<br />221.577 11.133 -2.220<br />228.070 11.135 -0.984<br />234.753 11.160 0.300<br />241.632 11.207 1.560<br />248.712 11.275 2.795<br />256.000 11.353 3.890<br />263.501 11.425 4.945<br />271.223 11.484 6.045<br />279.170 11.539 7.112<br />287.350 11.624 8.369<br />295.770 11.728 9.506<br />304.437 11.829 10.614<br />313.358 11.967 11.820<br />322.540 12.127 12.914<br />331.991 12.292 13.903<br />341.719 12.440 14.840<br />351.732 12.604 16.009<br />362.039 12.831 17.145<br />372.647 13.112 18.152<br />383.567 13.412 18.972<br />394.806 13.763 19.785<br />406.375 14.147 20.274<br />418.282 14.542 20.628<br />430.539 15.003 20.708<br />443.155 15.430 20.436<br />456.140 15.906 20.329<br />469.506 16.612 19.510<br />483.264 17.321 16.943<br />497.424 17.470 12.531<br />512.000 16.668 8.402<br />527.003 15.217 7.340<br />542.445 14.078 9.826<br />558.340 13.657 13.169<br />574.701 13.586 16.184<br />591.541 13.753 18.786<br />608.874 14.011 20.484<br />626.715 14.202 21.782<br />645.080 14.375 23.366<br />663.982 14.702 25.055<br />683.438 15.142 26.246<br />703.464 15.590 26.986<br />724.077 16.028 27.501<br />745.294 16.513 27.810<br />767.133 17.014 27.781<br />789.612 17.503 27.291<br />812.749 17.947 26.275<br />836.565 18.119 24.703<br />861.078 17.904 23.284<br />886.309 17.538 23.128<br />912.280 17.271 23.782<br />939.012 17.165 24.477<br />966.527 17.075 25.346<br />994.849 17.039 26.421<br />1024.000 17.077 27.514<br />1054.005 17.161 28.611<br />1084.890 17.268 29.711<br />1116.680 17.397 30.861<br />1149.401 17.558 32.146<br />1183.081 17.801 33.544<br />1217.748 18.145 34.942<br />1253.431 18.611 36.174<br />1290.159 19.145 37.104<br />1327.964 19.732 37.704<br />1366.876 20.300 37.979<br />1406.929 20.757 37.969<br />1448.155 21.235 38.095<br />1490.589 21.630 37.894<br />1534.266 21.827 37.546<br />1579.224 21.772 38.095<br />1625.499 21.972 39.447<br />1673.129 22.494 40.792<br />1722.156 23.149 41.727<br />1772.619 23.861 42.554<br />1824.561 24.702 43.284<br />1878.024 25.701 43.814<br />1933.055 26.946 44.014<br />1989.697 28.382 43.477<br />2048.000 29.763 41.950<br />2108.011 30.816 39.716<br />2169.780 31.482 37.154<br />2233.360 31.528 34.353<br />2298.802 30.879 32.292<br />2366.162 30.157 31.814<br />2435.496 29.961 31.599<br />2506.862 29.518 31.003<br />2580.318 28.939 31.593<br />2655.927 28.936 32.575<br />2733.752 29.031 32.654<br />2813.857 28.714 33.279<br />2896.309 28.878 34.584<br />2981.178 29.339 34.945<br />3068.533 29.371 35.024<br />3158.448 29.337 35.893<br />3250.997 29.544 36.978<br />3346.259 29.946 37.964<br />3444.312 30.507 38.767<br />3545.238 31.003 39.204<br />3649.121 31.461 39.696<br />3756.049 32.033 40.275<br />3866.109 32.624 40.434<br />3979.395 33.027 40.630<br />4096.000 33.413 40.947<br />4216.022 33.812 41.431<br />4339.561 34.280 41.999<br />4466.720 34.875 42.589<br />4597.605 35.557 43.024<br />4732.325 36.213 43.328<br />4870.992 36.872 43.627<br />5013.723 37.551 43.893<br />5160.637 38.242 44.094<br />5311.855 38.898 44.243<br />5467.504 39.537 44.434<br />5627.714 40.207 44.643<br />5792.619 40.887 44.811<br />5962.355 41.538 44.969<br />6137.066 42.192 45.208<br />6316.896 42.914 45.463<br />6501.995 43.684 45.678<br />6692.518 44.468 45.859<br />6888.623 45.266 46.021<br />7090.476 46.077 46.160<br />7298.242 46.901 46.281<br />7512.097 47.736 46.389<br />7732.218 48.584 46.484<br />7958.790 49.439 46.557<br />8192.000 50.295 46.625<br />8432.044 51.163 46.698<br />8679.122 52.049 46.763<br />8933.439 52.955 46.820<br />9195.209 53.874 46.850<br />9464.649 54.795 46.870<br />9741.985 55.720 46.876<br />10027.447 56.648 46.880<br />10321.273 57.574 46.877<br />10623.710 58.502 46.877<br />10935.008 59.422 46.887<br />11255.428 60.353 46.928<br />11585.238 61.324 46.983<br />11924.711 62.327 47.026<br />12274.132 63.344 47.058<br />12633.791 64.370 47.090<br />13003.989 65.416 47.123<br />13385.035 66.485 47.150<br />13777.247 67.571 47.166<br />14180.951 68.669 47.175<br />14596.485 69.783 47.182<br />15024.194 70.919 47.191<br />15464.437 72.074 47.193<br />15917.579 73.242 47.188<br />16384.000 74.418 47.171<br />16864.088 75.590 47.153<br />17358.243 76.761 47.145<br />17866.879 77.961 47.152<br />18390.418 79.200 47.161<br />18929.299 80.477 47.161<br />19483.969 81.600 47.096<br />20054.893 81.747 46.767<br />20642.546 78.395 44.909<br /><br /></pre>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-40931031281294418212008-11-28T22:31:00.000-08:002008-11-28T22:34:45.327-08:00Speakers vs Tubes - when do they play nice with each otherIt's not as simple as tubes like high impedance speakers and vice versa.<br /><br />Read this article, ... go catch some sleep and then read it again. <br />Wait a week.<br />Repeat<br />....<br /><br /><a href="http://www.symphonysound.com/articles/tubefriendly.html">http://www.symphonysound.com/articles/tubefriendly.html</a>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-79685907608062362602008-11-28T22:07:00.000-08:002008-11-28T22:25:19.624-08:00BlogWorthy - Crossover MashupDescription of various crossover types and their respective advantages / disadvantages/ <br /><a href="http://www.audioholics.com/education/loudspeaker-basics/filter-crossover-types-for-loudspeakers">http://www.audioholics.com/education/loudspeaker-basics/filter-crossover-types-for-loudspeakers</a><br /><br />In the same vein, here's a simple walk-through of designing an actual crossover for a 3 way loudspeaker<br /><a href="http://burningass.110mb.com/crossover.php">http://burningass.110mb.com/crossover.php</a><br /><br />And lastly, a basic crossover calculator.<br /><a href="http://www.ajdesigner.com/crossover/crossoverfirst.php">http://www.ajdesigner.com/crossover/crossoverfirst.php</a>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-69104451696581826012008-10-26T21:22:00.000-07:002008-10-26T21:25:55.186-07:00Theil and Small Parameters for the AudaxPR170MOAlso tested with the WT3 while it was in my possession, here are the T/S specs.<br /><br /><blockquote>* Piston Diameter = 133.3 mm<br />* f(s)= 97.57 Hz<br />* R(e)= 6.14 Ohms<br />* Z(max)= 27.44 Ohms<br />* Q(ms)= 1.754<br />* Q(es)= 0.505<br />* Q(ts)= 0.392<br />* V(as)= 10.820 liters (0.382 cubic feet)<br />* L(e)= 0.25 mH<br />* n(0)= 1.90 %<br />* SPL= 94.88 1W/1m<br />* M(ms)= 6.74 grams<br />* C(ms)= 0.39 mm/N<br />* BL= 7.08 </blockquote>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-52736357701075405302008-10-26T21:14:00.000-07:002009-04-06T18:15:16.407-07:00Theil and Small Parameters for the University C15W woofer (silver frame)<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://img412.imageshack.us/img412/5785/tankskq6.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 512px; height: 843px;" src="http://img412.imageshack.us/img412/5785/tankskq6.jpg" alt="" border="0" /></a><br />I recently had access to a Datyon Woofer Tester 3 to test the T/S parameters of this excellent vintage woofer. When I can, I'm also going to post comparative measurements using my ARTA jig. Of note, .. I consider the dual voice coil C15W to be a highly excellent woofer for my Karlson K-15 enclosure. Despite what literature would have one believe, I've sen Karlsons to be picky about what drivers they like (they prefer low mass cones, low Qts drivers). This driver+cabinet enclosure didn't just make the walls shake. It literally moved the whole first floor of place up and down. I don't think it made much bass below 50 Hz, but this is a real 50 Hz, not 50 Hz produced by some "subwoofer" you buy in the big-box store.<br /><br />What does a Karlson look like? Here's a picture (not mine)<br /><br /><br />Series Voice Coils<br /><blockquote>* Piston Diameter = 330.2 mm<br />* f(s)= 69.98 Hz<br />* R(e)= 6.63 Ohms<br />* Z(max)= 74.00 Ohms<br />* Q(ms)= 3.708<br />* Q(es)= 0.365<br />* Q(ts)= 0.332<br />* V(as)= 91.420 liters (3.228 cubic feet)<br />* L(e)= 1.41 mH<br />* n(0)= 8.19 %<br />* SPL= 101.20 1W/1m<br />* M(ms)= 58.27 grams<br />* C(ms)= 0.09 mm/N<br />* BL= 21.58</blockquote><br /><br />Parallel Voice Coils<br /><blockquote>* Piston Diameter = 330.2 mm<br />* f(s)= 69.98 Hz<br />* R(e)= 2.32 Ohms<br />* Z(max)= 18.89 Ohms<br />* Q(ms)= 3.965<br />* Q(es)= 0.554<br />* Q(ts)= 0.486<br />* V(as)= 91.420 liters (3.228 cubic feet)<br />* L(e)= 0.36 mH<br />* n(0)= 5.39 %<br />* SPL= 99.42 1W/1m<br />* M(ms)= 58.27 grams<br />* C(ms)= 0.09 mm/N<br />* BL= 10.35</blockquote>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com3tag:blogger.com,1999:blog-577620020709386742.post-53073831906121379032008-10-25T01:29:00.000-07:002008-10-25T01:44:39.862-07:00Unlocking Iphone SagaNot really audio related in the strictest of senses, but since an iphone is a fairly handy multimedia device, I figured this saga was blogworthy.<br /><br />In short, I bricked an iphone whyile trying to install the 3rd party App Installer using the excellent program <a href="http://www.ziphone.org/">Ziphone</a>. Had to crawl through tonnes of ill described articles and many juvenile youtube "how-to" guides.<br /><br />I'm linking to<a href="http://www.visionmasterdesigns.com/2008/08/downgrading-your-iphone-2-to-1-1-4-firmware/"> the article</a> that worked for me . I also found the following youtube useful to follow along in real time when trying to get the phone into DFU mode (timing is critical)<br /><br /><object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/Rb_ss0bljHY&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><embed src="http://www.youtube.com/v/Rb_ss0bljHY&hl=en&fs=1" type="application/x-shockwave-flash" allowfullscreen="true" width="425" height="344"></embed></object>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-40773444035582349062008-09-07T01:28:00.000-07:002008-09-20T11:24:52.490-07:0012b4a amp, version 2Looking to see if I could eke out any extra performance out of my <a href="http://zobsky.blogspot.com/2008/06/12b4a-amplifier.html">12b4a amp, version 1</a> , I tried the following<br />1. Increased cathode bypass resistor on the 12b4a output tubes to 250 uF . No audible change, so no changes there<br />2. Add film bypass capacitors to the power supply and cathode bypass electrolytic capacitors. Smoother sound, less grain. Definate yes.<br />3. Add a 0.5 ohm dropper resistor in one leg of the filament secondary to drop the filament voltage from 7V down to 6.3V. Ideally, you would want to use two 0.25 ohm in each leg of the supply, but come on, 0.5 ohm is miniscule compared to the power transformer's DCR. Worked like a charm.<br />4. Build a IXYS IXCP10M45 CCS and replace the film resistors on the 12AT7. I find that with the CCS<br /><ul><li>Gain is increased</li><li>Transparency is increased</li><li>Drive and also treble resolution are increased<br /></li><li>The warm "euphonic" sound effect is reduced. To be expected, but I kinda miss it.</li><li>The miniscule amount of hum (only heard with ear 1 cm from driver) I had before is pretty much gone (increased PSRR, I guess).<br /></li></ul>I varied the current from 2mA to 4.5 mA but backed ff to 3.5mA . At this point, plate voltage is abotu 150V. I don't have a lot of B+ to play around with so I'm going to be conservative. At first glance, the higher current seems to give the amp a bit more drive and a "heavier" sound, whereas the lower current results in a "lighter" more airy sound. I'll verify this upon further listening.<br /><br />Here's the new schematic:<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNafS6slbcAXjr2BuhklAgBEw_eG6Rnw_0kjcIu09MaCH1dOMMZqbd92awwtk-yxi8NNWlprvZEgoIjhgjIbshRj2ssPLkT-x_FzZVv_iBssMO4yjJgJWWjrFG_YyXDnJGwQag4ILIT_4/s1600-h/12b4a_SE_v2.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNafS6slbcAXjr2BuhklAgBEw_eG6Rnw_0kjcIu09MaCH1dOMMZqbd92awwtk-yxi8NNWlprvZEgoIjhgjIbshRj2ssPLkT-x_FzZVv_iBssMO4yjJgJWWjrFG_YyXDnJGwQag4ILIT_4/s320/12b4a_SE_v2.jpg" alt="" id="BLOGGER_PHOTO_ID_5243329589541766018" border="0" /></a><br /><br />Update: September 20, 2008 .<br />I occasionally noticed a little amount of "zzzzz" sound . It turns out there is a little blocking distortion action going on. "Kenpeter" suggested a couple of "fixes".I've tried the first circuit (<a href="http://www.diyaudio.com/forums/attachment.php?s=&postid=1607995&stamp=1221201218">http://www.diyaudio.com/forums/attachment.php?s=&postid=1607995&stamp=1221201218</a>) The debuging saga is documented at <a href="http://www.diyaudio.com/forums/showthread.php?s=&threadid=129577">http://www.diyaudio.com/forums/showthread.php?s=&threadid=129577</a><br /><br />Here's a link on <a href="http://www.aikenamps.com/BlockingDistortion.html">blocking distortion</a>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com1tag:blogger.com,1999:blog-577620020709386742.post-55232603897572293812008-07-19T09:46:00.001-07:002008-07-19T09:50:52.956-07:00Techpreservation - A great schematics resourceThis is a great repository of vintage audio schematics . Hard to believe that the information is free.<br /><a href="http://techpreservation.dyndns.org/schematics/">http://techpreservation.dyndns.org/schematics/</a><br /><span style="text-decoration: underline;"></span>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-48479083212844381412008-07-10T16:01:00.000-07:002008-07-10T16:11:16.969-07:00My line arrays<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://img167.imageshack.us/img167/8262/supertweetqw8.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 320px;" src="http://img167.imageshack.us/img167/8262/supertweetqw8.png" alt="" border="0" /></a><br />For what it's worth, here's a thread detailing a budget open baffle line array build of mine from last year. I used cheap $3.00 foster wide range drivers (sadly no longer widely available) , cheaper <a href="http://www.apexjr.com/">Apex Jr </a> tweeters and much cat 5 cable (yes, I'm cheap) crossed over around 5 KHz (lower would've been better, but I didn't want to risk incurring nasty tweeter distortion modes).<br /><br /><a href="http://www.diyaudio.com/forums/showthread.php?s=&threadid=99960">http://www.diyaudio.com/forums/showthread.php?s=&threadid=99960</a><br /><br />This design (being open baffle) needs a subwoofer below 60 - 80 Hz (I use a <a href="http://www.billfitzmaurice.com/">Fitzmaurice</a> TableTuba Horn Subwoofer) and the combo plays way better than the amount I spent on it. High efficiency is the way to go.<br /><br />Impedance is about 6 ohm and efficiency is the mid to upper 90s.V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-27893404344925472312008-06-18T15:34:00.000-07:002008-12-10T01:44:56.920-08:0012b4a amplifier<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmfdvSC-BkD6enU59EK4KcCZUR9w2EvnDPskO_aDM6-Gf0Pb2XpeClGqz6UP1F9PqPet9u3bKzMY3PdlJL7F8ucPGXT0pXAdsQrVUe0z7CMt-hYhR3QssAi-TouNywmTxpWPcVGxZ-IFM/s1600-h/12b4a.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmfdvSC-BkD6enU59EK4KcCZUR9w2EvnDPskO_aDM6-Gf0Pb2XpeClGqz6UP1F9PqPet9u3bKzMY3PdlJL7F8ucPGXT0pXAdsQrVUe0z7CMt-hYhR3QssAi-TouNywmTxpWPcVGxZ-IFM/s320/12b4a.jpg" alt="" id="BLOGGER_PHOTO_ID_5225660319783414914" border="0" /></a><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEr54IuuFO4wtP1r2hecA8XKPUIJRskvLZTYDPInz8FRgSLK_cOKHwT3eBOUO8XT6mndDTo8bVwNUGpTaevkE_yyCw23sxK6sXQ5YHho7t7pi3p7gYd698ZzRqTkklrJMBE-xV4yJ0sO4/s1600-h/12b4a_SE.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEr54IuuFO4wtP1r2hecA8XKPUIJRskvLZTYDPInz8FRgSLK_cOKHwT3eBOUO8XT6mndDTo8bVwNUGpTaevkE_yyCw23sxK6sXQ5YHho7t7pi3p7gYd698ZzRqTkklrJMBE-xV4yJ0sO4/s320/12b4a_SE.jpg" alt="" id="BLOGGER_PHOTO_ID_5224763094481668962" border="0" /></a><br /><br />I was bored, so I built a 12b4a single ended amplifier from my bottomless pit of unused electronics. Bias points for the outputs are roughly similar to Gaby Levinson's project listed at<br /><ul><li><a href="http://www.enjoythemusic.com/magazine/equipment/0902/levinson.htm">http://www.enjoythemusic.com/magazine/equipment/0902/levinson.htm</a></li><li><a href="http://www.enjoythemusic.com/Magazine/equipment/1002/levinson.htm">http://www.enjoythemusic.com/Magazine/equipment/1002/levinson.htm</a></li></ul>I have an extra 12AT7 lying around which I used as a driver, resistor loaded. I plan to CCS the plates when I can. Cathode bias is around 1.7 V via a single red LED per channel. I (optional) added a 10 ohm series resistor on each cathode to enable me to verify bias. I'm right around 3 mA per channel, which is below what the LEDs can handle.<br /><br />Transformers are 5K / 8 ohm transformers from an old SE 6BQ5 console for the outputs and a hefty low DCR (less than 10 ohm) power transformer from a fisher 800C . Rectification is UF4007 SS diodes bypassed by 1000V mica caps (o.1uF, IIRC). For what it's worth 12B4A tubes have a neat inbuilt slow turn on feature, so turn on nasties are minimized. The 12b4a cathodes are at 20V (24 mA).<br /><br />All other passives were generic off the shelf components from<a href="http://www.tannerelectronics.com/"> Tanner Electronics</a>, here in Dallas and the chassis is a gutted Intel 2U form factor router that I picked up for $3 at a surplus sale.<br /><br />I didn't pay too much attention to cosmetics, this being a budget project, but I suppose I'll eventually make an attempt to make this amp more presentable given how good it sounds.<br /><br />The sound is amazingly good for the 1.5W or so that it puts out. Not too much low bass (I blame the cheap OPTs for this) with an excellent mid bass and mid range. Very liquid sound that just sounds right. Highs are smooth without being excessively rolled off (okay, maybe just a little bit, but definately not in a old-school vintage sound way). I haven't even bothered decoupling the driver and output stages, or bypassing the electrolytics and yet, this amplifier sounds so "RIGHT" . These speakers take the edge right off my fostex full rangers and fill in the mid bass very nicely. Hum is pretty much non - existant even with ear to speaker. I used twin CLC filters, one for each channel to reduce the current load on each choke .<br /><br />Probably best with speakers of real life sensitivitiy above 95 - 97 dB/W/m. These sound "so - so with your typical "shoe-box" 2 - way monitor. Maybe okay for an office, but definately won't show their full potential unless paired with high efficiency speakers. I'd really like to compare these to a good DHT 45 SET .<br /><br />Update: September 20, 2008<br />the story continues at <a href="http://zobsky.blogspot.com/2008/09/12b4a-amp-version-2.html">http://zobsky.blogspot.com/2008/09/12b4a-amp-version-2.html</a>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com0tag:blogger.com,1999:blog-577620020709386742.post-1812459708515855942008-02-06T11:56:00.000-08:002008-12-10T01:44:57.142-08:00Frequency measurements with ARTA<span style="font-weight: bold;">Description</span><br />Here's a simple electret mic capsule / circuit I use for frequency response measurements, . .basically just a panasonic $2 <span style="">WM-61A (chosen for its linear response) capsule mounted on one end of a hollowed-out ball-point pen and a 9V battery and a couple of other miscelaneous components hanging off the other. I taped this contraption onto a spare tripod and voila !! . This is fed to the LINE-IN (not MIC) input on my audigy 2 sound card, which has a flat enough response for frequency response measaurements. I use ARTA for actual measurements.<br /><br />The only downside to this simple circuit is that it can't drive long lengths of cable (mine is a couple of meters long and works just fine).<br /></span> <a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://img458.imageshack.us/img458/820/micsh6.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 320px;" src="http://img458.imageshack.us/img458/820/micsh6.png" alt="" border="0" /></a><br /><br /><span style="font-weight: bold;">The circuit<br /> </span><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbhIGf162Q-HbNKxS0ZyyaBrqlULCumt5UO-eAPMGAY3GJWnzTpWRb1l4NCV2btddt2p_01ulhzcChnxw-cW-SXiERRBhX0qK2sNc3pIESC8ji2y2DJDR5RVlWYTyFvjKIgoh7YVU4CQE/s1600-h/simple_mic_preamp.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbhIGf162Q-HbNKxS0ZyyaBrqlULCumt5UO-eAPMGAY3GJWnzTpWRb1l4NCV2btddt2p_01ulhzcChnxw-cW-SXiERRBhX0qK2sNc3pIESC8ji2y2DJDR5RVlWYTyFvjKIgoh7YVU4CQE/s320/simple_mic_preamp.png" alt="" id="BLOGGER_PHOTO_ID_5224653954316386786" border="0" /></a><br /><br /><span style="font-weight: bold;">A sample measaurement</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://img295.imageshack.us/img295/7720/supertweetqp2.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 320px;" src="http://img295.imageshack.us/img295/7720/supertweetqp2.png" alt="" border="0" /></a>V.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com1tag:blogger.com,1999:blog-577620020709386742.post-79700033557635326392008-01-13T16:02:00.000-08:002008-12-10T01:44:57.743-08:00A simple loudspeaker measurement jig for ARTA<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIxKS-DlmhVqWibsomcXGBdJai0J0di0vDJXSM-3g5ZUk39TLwWVKQTETK5T4piSeRcP6lj_1Rnjh8xZFHrb9fMk86imdQZ_miyv5qgU0mNBfrfTk4apBNcxC3U0N-wfIT8Y-fC6UUL1I/s1600-h/arta_ckt.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhIxKS-DlmhVqWibsomcXGBdJai0J0di0vDJXSM-3g5ZUk39TLwWVKQTETK5T4piSeRcP6lj_1Rnjh8xZFHrb9fMk86imdQZ_miyv5qgU0mNBfrfTk4apBNcxC3U0N-wfIT8Y-fC6UUL1I/s320/arta_ckt.jpg" alt="" id="BLOGGER_PHOTO_ID_5155118178230278674" border="0" /></a><br />Here's a redux of a very useful simple circuit that, when used with the <a href="http://www.fesb.hr/%7Emateljan/arta/">ARTA </a>LIMP software running on a PC, allows you to easily measure loudspeaker impedance curves, RLC values of passive components at various frequencies, and TS parameters of loudspeaker drivers. You should be able to do all this with the FREE demo version of ARTA.<br /><br />It has saved me from the curse of <a href="http://www.speakerworkshop.com/">Speaker Workshop</a>, which is an extremely useful tool, but a real PITA to get going.<br /><br /><br />This jig is useful for low-power measurements. For higher power measurements, you will need some sort of protection devices on the PC Line-In sockets and also a power amplifier to drive the speaker. Regardless, the circuit above works, and works very well for what it does. I've ran it on a variety of drivers with my Audigy2 sound card and also the crappy on-board sound on my computer and the results obtained compare very favorably with the manufacturers specs and graphs.<br /><br />The way it works is the PC line-out powers the driver under test via a series resistor of known value. The line-in connections act as voltage probes fore and aft of this resistor, allowing the software to determine impedance variation with frequency. There are some fancy jigs out there, but this one works well and costs literally nothing to build . If you're cheap / lazy like me, you can forego the switch and merely disconnect the driver when calibrating the jig (do this everytime you re-connect it). This is probably a better / cheaper idea as the contact resistance of a typical cheap switch can vary between 0.5 - 3 ohm, .. fairly significant when you consider that the typical driver has a nominal impedance of 4 - 8 ohm .<br /><br />Also, I'd suggest disconnecting the jig when not using it, .. probably not the best idea to leave a loopback into the sound card long term.<br /><br />You will need<br />1. 3 RCA sockets<br />2. One single pole switch, or whatever you have lying around that works. Try to ensure that it doesn't have too high a contact resistance.<br />3. One calibration resistor, . the exact value is not too important, as long as you know what it is. I used a 14.7 ohm resistor made up of multiple larger equal valued resistors in parallel to reduce the effects of resistor to resistor variation.<br />4. One pair of binding posts.<br />5. One plastic enclosure to build this contraption into.<br />6. Two stereo-RCA to mini plug cables a.k.a "I POD" cables<br /><br /><span style="font-style: italic; font-weight: bold;">Note: sound card settings</span><br /><span style="font-style: italic;">Here's how my sound card is set up, as viewed from Windows Mixer . Your input and output settings may vary, depending on your specific hardware but try to note / check the following:<br /></span><ul><li><span style="font-style: italic;">The important thing to ensure is that you select the correct Line-In input in the Recording panel.</span></li><li><span style="font-style: italic;">Also, you may / may not need to mute the Line in on the Playback panel, as well as the Microphone in.<br /></span></li><li><span style="font-style: italic;">My Audigy 2 has a bunch of options and I had to experiment a bit initially trying the various inputs (some looped-back internally bypassing the calibration resistor:(.</span></li><li><span style="font-style: italic;">If you have an Audigy type card, be sure to check the "record without monitoring option" . See picture below.<br /></span></li><li><span style="font-style: italic;">If you get a channel imbalance of 0.0 dB when calibrating, you probably have an internal loopback.</span></li><li><span style="font-style: italic;">Once you get ARTA working, you may consider muting un-needed inputs / outputs .</span></li><li><span style="font-style: italic;">Watch out that you aren't too close to sources of electrical interference (such as CPU fans) as you can pick up spurious 120 Hz interference on impedance graphs.<br /></span></li></ul><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggl6KTtAWQQixzihVJQ6kJeafpr76KT3Qt3_q5ezRyfxZM5thyZJC3Uci_PY2NLivnetBlMQeLevNFloIe6Y758l_bXnqB3LbuHFAsG5EmI61Rgt1NdSkpgDA88Mg9sM0Ez8V_hBrRfq8/s1600-h/soundcard.png"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggl6KTtAWQQixzihVJQ6kJeafpr76KT3Qt3_q5ezRyfxZM5thyZJC3Uci_PY2NLivnetBlMQeLevNFloIe6Y758l_bXnqB3LbuHFAsG5EmI61Rgt1NdSkpgDA88Mg9sM0Ez8V_hBrRfq8/s320/soundcard.png" alt="" id="BLOGGER_PHOTO_ID_5179277650960682770" border="0" /></a><br /><br />You will want to read the ARTA / LIMP manual for a full description of the procedure but it really isn't too tough. Basically<br />1. Connect the cables between the PC and the jig, the jig and the driver under test and set the switch to OFF . If you haven't built in a switch, just make sure the driver is disconnected from the jig.<br />2. Calibrate the jig (configure the value of the calibration resistor, set the correct reference channel, set the appropriate input and output devices on your sound card, and adjust the levels so you don't clip the input). When calibrated, the jig should indicate a SMALL difference in channel levels (say 0.1 dB or so). If you have a large imbalance (greater than 2 - 3 dB), something is not connected correctly. If you have no imbalance, the output is being looped-back to the input within the sound card . Check for the correct input and output settings on your sound card.<br />3. Set the switch to ON<br />4. Press the red record button and within seconds, you should have an impedance curve.<br /><br />Here's an example (different specimen than the one used for T/S parameters further down this post):<br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3WmhHc7Q1AfOfzq92x1cmoigOrfBgeOlZFVnMDpC8CbUiPQ8S49ZD9Zj7wKqg2-g6rafaIrjcrg1x1M-8KpzTCCHrPBsJa7xKiAP8QXjuPx9p5RAcneRXgeMj30rqYq6Jr_jsZbAH8ew/s1600-h/fosterwidebandxh5.jpg"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3WmhHc7Q1AfOfzq92x1cmoigOrfBgeOlZFVnMDpC8CbUiPQ8S49ZD9Zj7wKqg2-g6rafaIrjcrg1x1M-8KpzTCCHrPBsJa7xKiAP8QXjuPx9p5RAcneRXgeMj30rqYq6Jr_jsZbAH8ew/s320/fosterwidebandxh5.jpg" alt="" id="BLOGGER_PHOTO_ID_5155123267766524450" border="0" /></a><br />Wasn't that easy?<br /><br />5. Now, if you want to go further and determine the <a href="http://en.wikipedia.org/wiki/Thiele/Small">TS parameters</a>, navigate to the Analyze / Loudspeaker parameters - Added mass method . Enter the DC resistance and the Membrane diameter (the diameter of the driver cone +1/3 of the surround thickness) and calculate the TS parameters. This will calculate most of the important stuff.<br /><br />6. Now close this window, go back to the graphs and navigate to Overlay / Set as overlay. This establishes a baseline for the Vas calculation.<br /><br />7. Add mass to the cone. The cheapest and easiest way I've found to this is to secure one or more pennies to the cone with small pieces of weather-stripping (light, easily removable and damp the coins). A U.S. penny's mass is 2.5 grams (on earth, at least). <a href="http://www.usmint.gov/mint_programs/circulatingCoins/index.cfm">Here </a>are the weights for some other US coins.<br /><br />8. Now, run an impedance sweep again. You should see the resonant frequency peak shift lower. You want to see a decrease of about 10 or more percent. If not, you haven't added enough mass.<br /><br />9. Stop the measurement and then navigate back to the Loudspeaker parameters - Added mass method window. Enter the total mass you had to add to the cone and re-calculate. If done correctly, you should see the Vas and a bunch of other parameters show up.<br /><br />Here's an example of what I get for a cheap foster wideband woofer<br /><br /><br /><br /><br /><span style="font-family:courier new;">Thiele-Small parameters:</span><br /><br /><span style="font-family:courier new;">Fs = 82.89 Hz</span><br /><span style="font-family:courier new;">Re = 7.80 ohms[dc]</span><br /><span style="font-family:courier new;">Le = 1115.28 uH</span><br /><span style="font-family:courier new;">L2 = 437.31 uH</span><br /><span style="font-family:courier new;">R2 = 12.76 ohms</span><br /><span style="font-family:courier new;">Qt = 1.17</span><br /><span style="font-family:courier new;">Qes = 1.47</span><br /><span style="font-family:courier new;">Qms = 5.81</span><br /><span style="font-family:courier new;">Mms = 4.89 grams</span><br /><span style="font-family:courier new;">Rms = 0.438236 kg/s</span><br /><span style="font-family:courier new;">Cms = 0.000754 m/N</span><br /><span style="font-family:courier new;">Vas = 7.86 liters</span><br /><span style="font-family:courier new;">Sd= 86.18 cm^2</span><br /><span style="font-family:courier new;">Bl = 3.679200 Tm</span><br /><span style="font-family:courier new;">ETA = 0.29 %</span><br /><span style="font-family:courier new;">Lp(2.83V/1m) = 86.89 dB</span><br /><br /><span style="font-family:courier new;">Added Mass Method:</span><br /><span style="font-family:courier new;">Added mass = 2.50 grams</span><br /><span style="font-family:courier new;">Diameter= 10.48 cm</span><br /><br />Compare this with the manufacturer's specs, not a perfect match but not bad, considering manufacturing variations, and the fact that I wasn't paying too much attention when testing this.<br /><p style="font-family: courier new;">Foster 2422 264 00504<br />Paper cone, cloth surround wide band woofer.</p><p style="font-family: courier new;">8 ohm<br />87.3dB<br />Fs 80.7Hz<br />Vas 10 liters<br />Qms 4.267<br />Qes 1.375<br />Qts 1.040<br />BL 3.57<br />Cms 808.7 uM/N<br />Mms 4.81g<br />Re 7.2 ohm<br />Krm 1.155<br />Kxm 6.832<br />Erm 0.818<br />Exm 0.716<br />Sd 0.0094 sqM<br />Le 0.57mH @ 1kHz</p><br />EnjoyV.G.B.http://www.blogger.com/profile/11539509540138395759noreply@blogger.com6