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I have been working on some projects pro/home audio and have been looking around trying to find equipment/software that would let me measure THD or THD+N.
You guys have any clues?
You guys have any clues?
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-Joe -
Go to http://audio.rightmark.org/index_new.shtml and download RMAA.
What are you going to measure?
/Peter -
What level are you attempting to measure at? .000X% or 1 or 2%? I have found that 'inexpensive or free' PC programs can do just fine until you need really good resolution below ~.01%. I have been able to purchase equipment that will measure down to .002% reliably for pennies on the dollar if you look for it. And there is modern instrumentation available also.
ChuckComment
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Chas,
are you saying that RMAA is unsufficient (is that a word?) for low level measurements?
I have a Echoaudio Audiofire4 audiointerface which measures down to 0.0008% THD in loopback mode (equivalent to 2nd and 3rd harmonics at -107dB). That means distortion from the DA stage and the AD stage is included.
/PeterComment
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I would not say it is insufficient but....
Here is a link to a rightmark test of a simple ordinary Creative Labs SB Live! sound card. Test using RMAA With specifications like this who needs Ayre equipment to playback audio?! I do not for one minute believe that a $30 external USB sound card has distortion and noise levels as those listed. I do believe that those measurements are what the user measured. I take them with a grain of salt and I would be amazed if I could duplicate those measurements on my Tektronix gear.
ChuckComment
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I am also surprised to see those numbers on THAT card. Makes me wonder if someone is joking here. Those numbers are better than Echoaudio and Lynx which costs about $500-1000.
That said, the RMAA numbers that I get when measuring my Audiofire4 are close to what Echo publish on their website and those are lab numbers not numbers from the chip manufacturer.
You can go to RMAA's website to see measurements of various cards and there's a big diference between them. Not like "everything measures good" with RMAA.
I thought Ayre's products measured poorly? so maybe those should not be compared to products that have SOTA measurements. I don't doubt that Ayre makes nice stuff that sounds good, however I wonder if they are neutral and transparent, many "high end" products are not.
/PeterComment
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Actually, I got pretty damn good numbers when I set up my SB Live! for use with Speaker Workshop a few months ago. When I actualy put it on my 'analog' Tektronix gear and checked distortion, I got a much different measurement. .00X% with RMAA and .oX% with test gear. Which is why I do not hold free or low cost audio measurement software in very high regard for measuring electronics. Acoustical measurement software is another story, but it all must be taken with a grain of salt.
Hey, that Audiofire card looks like an excellent piece of gear by the way! It probably does measure very well both in a computer and on a lab bench. They look like serious company that is promoting an honest well made product.
Yes, Ayre will measure quite well and hold its own with other components, but then we get into the fact that measurement does not tell the whole story and is just a piece of the puzzle to be used in the final judgement. I have measured electronics that were not particularly great on the bench but sound very, very good.Comment
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