THD vs. Hearing – Please Help.

[b_panther_g]

“If a cetain type of distortion is known to be inaudible at a pre determined level, is it bad? The way I'm looking at it is if it's inaudible I'm not worried about it and I can direct my attention to more worthy matters.”

Good point. There is no point in lowering inaudible distortion.



“You are far more optimistic than I am. I hope you're right however.”

I figure that Hi-End audio is a relatively small industry. More and more people interested in this hobby (or obsession or addiction) are surfing the internet. If there is a truly superior product and the company knows how to sell it, interested consumers will buy.

If there is a truly great speaker and people can afford it, they will buy it.

 

[WmAx]

Dan, please quote the people to which you are replying. I use the linear mode view and it is difficult to discern which reply is addressed to whom.

Thanks.

-Chris

Yes and no. Loudspeakers typically put out 2nd, 3rd, and 4th order harmonics. Note some of the waterfall plots taken on loudseakers. Then note audibilty of upper order distortions like 5th order distortion on up as opposed to the audibilty of lower order distortion. Once again, it's just not that simple, but yes I would like to see some of the measurements you have described. Who knows, it might embarass the loudspeaker industry enough to do something about it. ( O.K., I'm dreaming here)
In addition, I stongly suspect that many people are simply used to hearing certain kinds of distortion and "learned" to accept this as normal.

d.b.
P.S. Bongiorno did note that the musical scale does deviate from the "perfect" electronic scale, and he is correct. In the treble region the musical scale is "bent" so to speak, and I think this is one of the reasons that upper order distortion is considered harsh and aggravating. It's almost (?) a form of dissonance.

 

[WmAx]

A bit off topic, but still interesting: I came across this very interesting hearing test(posted by someone on the madisound board). It is not a harmonic distortion test, but a simulator of the phase modulation distortion that occurs when playing a wide band across a single transducer that has signifiant incursion/excursion.

http://www.klippel.de/aura/test.php?speaker_music=6+inch+driver~Music+-+Pop&outputDevice=Headset&experience=Yes

My score on this particular test was -39dB when using the vocal part as a reference and using a Sony MDR-7506 headset. I might be able to get to the -45 if I repeated the test several times, but I grew tired of the test...



If you want to try your hand at THD, you can download ABX software from:

www.pcabx.com

and at the bottom of the following page, you will find some distortion samples(distorton order and amplitude is located in the filenames, note that these are isolated harmonic tests--for example they are exclusivly containng a particular order harmonic, not combinations of harmonics):

http://www.pcabx.com/training/index.htm

-Chris