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Speaker Asylum General speaker questions for audio and home theater. |
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Speaker Asylum General speaker questions for audio and home theater. |
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In Reply to: My goodness posted by E-Stat on March 12, 2025 at 17:30:42:
Was able to sit and read the link to John Atkinsons measurements of the magnepan MG3.6/R speaker. Yes, these are difficult speakers to measure due to physical size. But despite that John's years of experience really shows. I was looking for magnepan factory measurements but like many high-end makers they do not show the measurements. But I was able to find a brief description from Magnepan of the MG3.6R Description: (Three-way, Floor standing, planar dipole loudspeaker. Drive-units: 500-in 2 planar-magnetic bass drivers, 199-in 2 planar-magnetic midrange driver, 0.16" by 55" ribbon tweeter. Crossover frequencies: 200Hz and 1.7kHz. Frequency response: 34Hz-40kHz, ±3dB.)
So according to magnepan the speakers should play from 34 HZ to 40 KHZ within + or - 3dB So plus or minus 3dB deviation. Now take a look at John's measurements; they are only 2.5dB off, not bad at all for an editor of a magazine that does not design speakers and is doing the measurements in his own home.
If you look, John has a 5.49dB dip at 2000 KHZ and a spike of around 5.5 dB around 15000 KHZ that is on axis line 0.00 in the graph pictured. That's around 2.5 dB difference from the manufacturer, not bad at all.
When manufacturers measure a tall speaker, it is difficult so most manufacturers will move the mike, take measurements in various locations and then combine the results. This might sound like cheating but how else are you going to measure a tall speaker with a microphone 1 meter away? if the mic is in the center of the speaker, it will be far off the vertical axis of the tweeter and woofer. So, it is common practice to take multiple measurements with the microphone in more favorable positions then combine those measurements. It's not cheating, it's a necessity.
If you ever look at any old JBL or Altec literature you will see how they used to measure tall theater speakers Farfield so you would see a speaker rated at 56dB @ 1 watt/2.83 volts input at 30 feet take that measurement at today's standard 1 meter so the microphone is literally 27 feet closer and it would measure 98dB @ 1 watt/2.83 volts they measured from father away to get a flatter response those old engineers with math kick ass !!!! i would love to see them old school designers with today's tools that would be crazy!!!.
It seems like John Atkinson gets some hate thrown his way not just in this forum but in all audio forums and I have a theory why some people do not give him any respect. I think these people don't really understand the measurements and a lot of times people will try to discredit what they do not understand or even sometimes attack what they don't understand.
Fact is John is one of the few people in the audiophile community that is spending his own time at his home measuring speakers fairly and honestly to help the audio consumer. And for that I applaud him he does not have to do it. He does it because he is passionate about his hobby, and it helps his magazine's readers make informed decisions with their hard-earned money. Who in the world would fault him for that?
If people do not trust his measurements, they can always go and learn more than what John knows. Then seek employment in the audio industry measure speakers accurately and honestly and then publish the results. Until then they have nothing to say on the subject that is credible.
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Follow Ups
- RE: My goodness - seancuster71@gmail.com 16:01:30 03/13/25 (4)
- RE: My goodness - E-Stat 17:06:19 03/13/25 (3)
- RE: My goodness - seancuster71@gmail.com 17:57:53 03/13/25 (2)
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