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McCauley M421 Quad 21" Subwoofer
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<blockquote data-quote="Bennett Prescott" data-source="post: 32818" data-attributes="member: 4"><p>More McCauley M421 Measurements</p><p></p><p>[ATTACH]149807[/ATTACH]Took the M421s out again for two gigs in two different venues. Southside Johnny and the Asbury Jukes at the Stone Pony Summer Stage, followed by Kid Cudi the next day in Convention Hall. Set up the usual subwoofers stage left and right as an end-fire array, with the M421s front and center. I drove each set of subwoofers off a separate aux so it would be possible to send any source to either or both. This was fun because it allowed me to play with different subwoofer patterns in this outdoor venue, plus it was an easy way to listen to both sets of subwoofers and play with a "dual PA", trying to get even more output and sonic clarity by putting dissimilar sources in different loudspeaker arrays.</p><p></p><p>As requested by Daniel, I used only basic processing. Butterworth 4th order HPF at 25Hz, and Linkwitz-Riley 4th order LPF at 100Hz (the XTA DSP I used to process the M421s didn't go any higher than 24dB/oct). I have to admit that I also took 6dB out at about 170Hz, Q of 3. Whether this had any noticeable effect once the low pass was applied I didn't spend much time on, but it made me happier.</p><p></p><p>Naturally, I wanted to continue to gather more measurement data on these subwoofers. Earlier in this thread I expressed doubts as to their -3dB specification, and I definitely wanted to go through my entire measurement system to ensure that wasn't measurement error on my part. First, I ran a loopback test on my measurement interface to make sure it was behaving linearly. I looked around but I couldn't find any XLR cables, so I used an APB Dynasonics Spectra Ti between my outputs and inputs instead...</p><p></p><p>[ATTACH]149809[/ATTACH]</p><p>Looks like any measurement error isn't in my USB audio interface. Next to check my measurement microphone. I brought along my recently calibrated (thanks, Hammer!) B&K 4007 to verify my results and took acoustic measurements of the M421s unprocessed with both my fancy mic and my cheap mic (with the capsule in approximately the same position). I then also took a trace with the applied processing using my cheap mic, and compared to the measurement I took a few weeks before at Colt's Neck High School just to make sure I was getting consistent results. In this next screenshot the red and blue traces are my expensive mic and cheap mic, respectively. The yellow trace is with applied processing, and the green trace way in the background is the measurement I took at Colt's Neck. These measurements are all MTW in Smaart 7, 1/48 octave smoothing, and a 6 second average.</p><p></p><p>[ATTACH]149808[/ATTACH]</p><p>I think, based on these measurements, that I am comfortable making a few claims. <ol> <li data-xf-list-type="ol">At low frequencies (<1-2kHz at least) there is no meaningful difference between a $1,800 microphone and an $80 microphone. (obviously there are durability, temp stability, etc, differences but they are not significant in this environment)</li> <li data-xf-list-type="ol">The McCauley M421 has a -3dB low frequency point, before processing, of about 27Hz. That's about 1/3 octave higher than what they claim on the spec sheet.</li> <li data-xf-list-type="ol">The M421 has a big ass peak at about 65Hz. Whether this is desirable or not is really up to the user.</li> </ol><p>I ran with the specified and measured processing all weekend. I will certainly agree that it made the sub more interesting. If I equalize out that approximately 65Hz bump the result is an unexciting subwoofer. It looks a little peakier than it sounds, but this sub definitely generates above and beyond kick drum thump when you turn it up! Even though its 30Hz level is 4-6dB less than its 65Hz level the subwoofer still sounds like it goes nice and low, but it is definitely characterized by that response peak. If you want a subwoofer that sounds enormous you might want to take at least 3dB out of that region, but if you want a subwoofer that sounds like it is going to kill you leave it in.</p></blockquote><p></p>
[QUOTE="Bennett Prescott, post: 32818, member: 4"] More McCauley M421 Measurements [ATTACH=CONFIG]149807.vB5-legacyid=1721[/ATTACH]Took the M421s out again for two gigs in two different venues. Southside Johnny and the Asbury Jukes at the Stone Pony Summer Stage, followed by Kid Cudi the next day in Convention Hall. Set up the usual subwoofers stage left and right as an end-fire array, with the M421s front and center. I drove each set of subwoofers off a separate aux so it would be possible to send any source to either or both. This was fun because it allowed me to play with different subwoofer patterns in this outdoor venue, plus it was an easy way to listen to both sets of subwoofers and play with a "dual PA", trying to get even more output and sonic clarity by putting dissimilar sources in different loudspeaker arrays. As requested by Daniel, I used only basic processing. Butterworth 4th order HPF at 25Hz, and Linkwitz-Riley 4th order LPF at 100Hz (the XTA DSP I used to process the M421s didn't go any higher than 24dB/oct). I have to admit that I also took 6dB out at about 170Hz, Q of 3. Whether this had any noticeable effect once the low pass was applied I didn't spend much time on, but it made me happier. Naturally, I wanted to continue to gather more measurement data on these subwoofers. Earlier in this thread I expressed doubts as to their -3dB specification, and I definitely wanted to go through my entire measurement system to ensure that wasn't measurement error on my part. First, I ran a loopback test on my measurement interface to make sure it was behaving linearly. I looked around but I couldn't find any XLR cables, so I used an APB Dynasonics Spectra Ti between my outputs and inputs instead... [ATTACH=CONFIG]149809.vB5-legacyid=1725[/ATTACH] Looks like any measurement error isn't in my USB audio interface. Next to check my measurement microphone. I brought along my recently calibrated (thanks, Hammer!) B&K 4007 to verify my results and took acoustic measurements of the M421s unprocessed with both my fancy mic and my cheap mic (with the capsule in approximately the same position). I then also took a trace with the applied processing using my cheap mic, and compared to the measurement I took a few weeks before at Colt's Neck High School just to make sure I was getting consistent results. In this next screenshot the red and blue traces are my expensive mic and cheap mic, respectively. The yellow trace is with applied processing, and the green trace way in the background is the measurement I took at Colt's Neck. These measurements are all MTW in Smaart 7, 1/48 octave smoothing, and a 6 second average. [ATTACH=CONFIG]149808.vB5-legacyid=1724[/ATTACH] I think, based on these measurements, that I am comfortable making a few claims.[LIST=1] [*]At low frequencies (<1-2kHz at least) there is no meaningful difference between a $1,800 microphone and an $80 microphone. (obviously there are durability, temp stability, etc, differences but they are not significant in this environment) [*]The McCauley M421 has a -3dB low frequency point, before processing, of about 27Hz. That's about 1/3 octave higher than what they claim on the spec sheet. [*]The M421 has a big ass peak at about 65Hz. Whether this is desirable or not is really up to the user. [/LIST]I ran with the specified and measured processing all weekend. I will certainly agree that it made the sub more interesting. If I equalize out that approximately 65Hz bump the result is an unexciting subwoofer. It looks a little peakier than it sounds, but this sub definitely generates above and beyond kick drum thump when you turn it up! Even though its 30Hz level is 4-6dB less than its 65Hz level the subwoofer still sounds like it goes nice and low, but it is definitely characterized by that response peak. If you want a subwoofer that sounds enormous you might want to take at least 3dB out of that region, but if you want a subwoofer that sounds like it is going to kill you leave it in. [/QUOTE]
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