Axiom Home Page Forums General Discussion Home Theater AVR or pre amp recommendations? Going 4K

I like Old-Fashions!

Can anyone speak to the difference (or lack thereof) between sound quality when using a dedicated pre-pro vs a receiver with pre-outs? Does a pre-pro sound noticeably cleaner for HT, all else being the same?

Can't speak for real life as I have not ever done an A/B test ... but having been an audio designer (back in the 80's and not for Hifi stuff), and only speaking for my self, I doubt I could hear the difference between the two given reasonably designed units (and assuming your by passing all the surround and room correction, etc.)

I can't tell you from experience because I've never done an A/B. If one has lower THD+N and higher S/N, I would expect that one to sound better. Both of those figures result in improved reproduction of microdynamics. Microdynamics are responsible for imaging and holography.

Mojo ... give the guy some numbers ...
What do you think should be the cut off for those ... where it become just a spec and not audible ... (also many times there are trade offs being made to get a spec ... usually dictated by marketing ... who IMHO are mostly made up of brain dead zombies out to sell product to the unknowing public. My apologies to the marketeers out there.)

So is 0.01 THD much better then say 0.1 THD or even .3THD?? Do you think you can hear it? how about a S/N below 100db ...

Things get a bit murky when talking about THD, as there is no universal standard for measuring it. As you say, specs have become the domain of marketing.

bman84,

Been a long time since I did one of these measurements but there are only two variables to play with: the fundamental frequency and the level. The standard frequency I always used was 1kHz. As for level ... if I remember correctly, I think I put the amp into clip and then backed it off till the THD stopped falling. This also is probably the best point for THD+N.

That said I'm sure some played around with both and then only give you the best THD number.

One more thing ... peoples sensitivity to THD varies with frequency ...

For THD, there are three. The third is the number of harmonic products measured.

yup .. your right Mojo.

Also nobody gives you the full spec. A fully specified spec should read
Less then 0.01 THD+N, at max gain, 20Hz to 20kHz, 20kHz window, input 1V peak to peak ...

This BTW would be an excellent spec ... even IMO if it said 0.1 THD+N

On this topic have any of you guys joined Gene of Audioholics cause. Truth in power ratings.
He's planning to send a petition to Sound United. To stop the inflated power ratings.