How bad is .2% THD (1 Viewer)

[Glen_L]

Here's a relevant link to a website I found a couple of days ago. On this particular page is a wav file that demonstrates THD. FWIW, I heard the 1% THD very easily on my system.

 

[Saurav]

That's a pure tone though, remember that. I think it gets back to what I said - if you buy gear for the numbers (or if you sit and listen to pure tones, which is the same thing as far as I'm concerned) ...
And the main issue being discussed here is relative amounts of THD. Since the best speakers are apparently 10 times worst than the worst amplifiers, I agree with Michael Price's statement above.
Of course, just IMO.

 

[Phil Mays]

This is an interesting exchange. I have been seriously considering upgrading my Onkyo 797 as it has .08% THD. The denon 4802 and up have .05% and some amps I was looking at have .03% THD.

I never knew speakers have a THD factor. If I understood correctly horn loaded speakers have less distortion. Any thought on THD with Klipsch speakers?

Phil

 

[Saurav]

If I understood correctly horn loaded speakers have less distortion.

Generally speaking, maybe. However, since there is much more to overall sound quality than just THD, there is no guarantee that you'll get good sound by getting horn speakers. Frequency response is an issue, room interactions are a BIG issue, impedance matching between the speaker and the amp is an issue, and so on. I think all of these will have a bigger effect on the sound than the THD of any component.

 

[Mark Tranchant]

I have been seriously considering upgrading my Onkyo 797 as it has .08% THD. The denon 4802 and up have .05% and some amps I was looking at have .03% THD.

Phil - Don't use numbers like these as a basis to throw money around. They are so easily "manipulated" by manufacturers as to be meaningless. Use your ears - get the other amps into your house and try them out.

For example, the manufacturers could quote maximum THD at a reasonable power level across the audio range (e.g. 10W 20-20kHz), or just provide a single percentage figure which would be the lowest they could achieve at optimum (probably tiny) output and a single frequency.

Compare some of the manufacturers figures against the lab reports some hi-fi magazines give...

An excellent example of marketing hype is power output. Look at those 500W computer speakers that run off a wall adaptor. Now find a genuine 500W PA speaker - does it look similar?

 

[Ferran Mazzanti]

It's nice how one can learn from the theads... I was a little bit worried when buought my SR6200 because it has a 0.05% THD, while my old stereo amp (Marantz also, PM-55 I think) has 0.001%THD listed in the specs. In any case I must say that the 6200 sounds a little bit better than the other to me, and that may indicate that THD (at these figures) is not that relevant...
One more thing that I keep wondering is about the hiss: as Samuel Des and Saurav say, signal to noise ratio is somehow a measure of it. Now my 6200 has a ration of 105db's, while I can start to hear the hiss at +5db's volume. Considering that min volume is reported as -75 db's, +5db's makes a difference of 80db's, still far from the 105... how can this be? Or am I missing something?

 

[Aslam Imran]

Thank you John for educating me.

 

[Mark Tranchant]

The -75dB is the minimum volume level available to you. If the amp went to -100, the signal should be at the same level as the hiss is at +5.

Basically, the 105dB figure claims that the noise floor is 105dB below the optimum signal level - that is, the maximum level the electronics can deal with before distorting. You'll find that the amp rarely actually deals with signals of that level as it would have no headroom. So your "real-world" ratio is probably 10dB or so worse than that.

Again, don't get hung up on the numbers. If the hiss isn't audible in normal use, that's fine. And again, the effect is worsened by multiple devices: the noise from the (analogue) source adds to the noise from the amp.