Thd

[mayho]

all things being equal, is there any difference in a receiver rated 0.08, and 0.05 THD? Thanks. Mayho

 

[zumbo]

Yes. .03

Honestly, both are below human detection.

 

[Ampdog]

Excellent, Zumbo

Agreeing with Zumbo, I must nonetheless add: Thd has become a meaningless parameter, in as much as giving a true idea of what an amplifier will sound like.

Not to burden with a whole tutorial, but with semiconductor amplifiers the harmonic content is of prime importance, but is seldom given. Briefly, high order harmonic distortion (7th, 9th, 11th etc.) generated can form very discordant combinations even in minute quantities. On the other hand the ear will "tolerate" a fair amount of 2nd and 3rd harmonic distortion. Thus one can get an amplifier with a low thd figure, but if there are high order harmonics it will generate what is called listener fatigue. On the other hand an amplifier with double the thd, if it consists of only 2nd and 3rd harmonics, will sound perfectly fine.

This is a very brief description, Mayho, not to bore you, just to indicate that thd is not necessarily meaningful.

 

[mayho]

so what makes a difference? when shopping for a receiver/amp what do I look for to get "audiophile sound? Thanks

 

[PENG]

Excellent, Zumbo

Agreeing with Zumbo, I must nonetheless add: Thd has become a meaningless parameter, in as much as giving a true idea of what an amplifier will sound like.

Not to burden with a whole tutorial, but with semiconductor amplifiers the harmonic content is of prime importance, but is seldom given. Briefly, high order harmonic distortion (7th, 9th, 11th etc.) generated can form very discordant combinations even in minute quantities. On the other hand the ear will "tolerate" a fair amount of 2nd and 3rd harmonic distortion. Thus one can get an amplifier with a low thd figure, but if there are high order harmonics it will generate what is called listener fatigue. On the other hand an amplifier with double the thd, if it consists of only 2nd and 3rd harmonics, will sound perfectly fine.

Then why did you agree with zumbo? THD, total harmonic distortion includes all harmonics, 2nd, 3rd,............nth harmonics. So if THD is <0.08%, and you agreed with zumbo, then it is not detectable by human, regardless of what order of harmonics are produced.

 

[skizzerflake]

so what makes a difference? when shopping for a receiver/amp what do I look for to get "audiophile sound? Thanks

You don't look, you listen for audiophile sound. No sarcasm intended, much of the audiophile religion is centered around the idea that trained ears can hear things that do not appear in published numbers about components. Any competently manufactured and connected receiver or amplifier will provide the possibility of excellent sound. The biggest factor is to eliminate a lot of DA or AD conversions and to use the smallest amount of digital processing to do the job. I suggest a receiver or amp that has a "straight" mode (like Yamaha) with minimal processing for those moments when you want to listen to undiluted stereo music. DSP for synthesized surround in music is up for grabs; browse through the available modes and pick one that feels good. For movies, I think the big system elements (speakers, room and subwoofer) will matter much more than some esoterica about perfect amplifiers or $100/foot wires.