Stan
February 16th, 2007, 8:42 PM
Have you guys tried the Klippel Test lately? You compare music which is clean versus the same brief clip with some distortion. Then you choose which is distorted. A or B. It gets harder and harder (less and less distortion) until your limit is found.
http://www.klippel-listeningtest.de/lt/
I come out in the -27 db to -33 db range in two tries, that comes out to about 2-4% distortion as my reliable limit on that music with the equipment used at the time. Bose Quietcomfort 2 headphones plugged into an old PC with a built in sound card. This is with the Tracey Chapman song & "music-pop / 6 inch driver". I think I can do a bit better on a different 'puter as the one I tried it on has a slight variable static at times, like a mosquito noise with the volume down and nothing playing. Maybe - three more dB better results, but not too much more because it is not an easy test. I think that a -45 dB rating is very, very tough to achieve on Music...that would be about 0.5%, which is stellar on such a signal.
Here is what a results graph looks like. Hmm, I feel like I can do better than that, lol.
http://www.pbase.com/sjmarcy/image/74504750/original.jpg
It is much easier to hear harmonic distortion on sine wave signals in the mid frequencies if you ever try that - there are fewer distractions. There are also various other tests to try out at that site. We are much more tolerant of some distortion in the bass ranges than higher up...it can make music sound warmer / louder if it is mostly 2nd / 3rd order. There can be a sub locatability aspect however. Since the harmonics are often greater than the crossover frequency in use, if the sub generated the harmonics. Since they originate *after* the crossover. So your 80 Hz crossover does not mean that nothing can come out of the sub above 80 Hz except rolled off bass.
Axiom Audio has some tests they shared here: http://www.axiomaudio.com/distortion.html# There are some interesting graphs.
Enjoy.
Stan
sjmarcy
http://www.klippel-listeningtest.de/lt/
I come out in the -27 db to -33 db range in two tries, that comes out to about 2-4% distortion as my reliable limit on that music with the equipment used at the time. Bose Quietcomfort 2 headphones plugged into an old PC with a built in sound card. This is with the Tracey Chapman song & "music-pop / 6 inch driver". I think I can do a bit better on a different 'puter as the one I tried it on has a slight variable static at times, like a mosquito noise with the volume down and nothing playing. Maybe - three more dB better results, but not too much more because it is not an easy test. I think that a -45 dB rating is very, very tough to achieve on Music...that would be about 0.5%, which is stellar on such a signal.
Here is what a results graph looks like. Hmm, I feel like I can do better than that, lol.
http://www.pbase.com/sjmarcy/image/74504750/original.jpg
It is much easier to hear harmonic distortion on sine wave signals in the mid frequencies if you ever try that - there are fewer distractions. There are also various other tests to try out at that site. We are much more tolerant of some distortion in the bass ranges than higher up...it can make music sound warmer / louder if it is mostly 2nd / 3rd order. There can be a sub locatability aspect however. Since the harmonics are often greater than the crossover frequency in use, if the sub generated the harmonics. Since they originate *after* the crossover. So your 80 Hz crossover does not mean that nothing can come out of the sub above 80 Hz except rolled off bass.
Axiom Audio has some tests they shared here: http://www.axiomaudio.com/distortion.html# There are some interesting graphs.
Enjoy.
Stan
sjmarcy