How important is having low THD in a receiver?

Discussion in 'Archived Threads 2001-2004' started by Steven_B, Sep 14, 2001.

  1. Steven_B

    Steven_B Agent

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    I ask because I'm looking at two receivers, one has a Total Harmonic Distortion of .04 and the other .09. Should this be the deciding factor.
     
  2. Matt Wallace

    Matt Wallace Second Unit

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    At those levels, no. In very general terms, THD with a "0" in front is very good and acceptable. Obviously, the lower the better, but when you're talking about something in hundreths of a percent, you're getting into fanatism. Now, if it was .9 vs .04, you've got more to think about, although there should be other things in the factoring that tip you in one direction. Hope this helps.
    Matt
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  3. KeithH

    KeithH Lead Actor

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    I agree with Matt, but I'll add a caveat based on personal experience. Generally, a THD
     
  4. Ted Lee

    Ted Lee Lead Actor

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  5. Steven_B

    Steven_B Agent

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    I appreciate your help guys. I have been looking for some time at receivers to replace my old one that fried on me. Sorry about getting so technical with you guys. I had been wanting to upgrade my non digital receiver for a more recent model, so I used this opportunity to convince my wife we needed a new one. At first I was conservative trying to look at models that would run my current equipment CD, VCR, and TV. I eventually started to drift off into the wow I got to have that, oh that's got to be important I'll get one with that feature. Suffice it to say I recently grounded my self and want a system that can run my current equipment and room for some growth (DVD, Digital Satellite). So I have narrowed it down to around the $500-600 dollar range. Online, the models that seem to fit nice here with respectable reviews and features are the Yamaha RX-V1000-800, and Pioneer's Elite VSX-35TX. I now guys what sounds good to me is what I should get. However I don't have that ability since I don't live near any distributors that are equipped with listening studios. So I need your trained ears to help.
     
  6. Ted Lee

    Ted Lee Lead Actor

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  7. Shanthi

    Shanthi Stunt Coordinator

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    I agree with mark, these reciver give you THD at certain Hz, it does not mean that they are good at all other Hz. I have seen .01%THD at 1K and 10% and lower and higher range.
    I kind of agree that lower THD are important.
    my 2 cents...
     
  8. Ted Lee

    Ted Lee Lead Actor

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    i'm much more leary of a spec if it isn't written properly:
    it needs to look something like "
     
  9. Chris PC

    Chris PC Producer

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    I think what some people are trying to say, is that even though THD alone is not indicative of good sound, and can even be higher on better sounding amps, in the lower quality mid-end stuff, THD CAN correlate with sound quality. I think this might actually just be a marketing ploy, so the receiver company can say, "This amp is 80 watts per channel at 0.08 THD from 20-20K and this amp is 105 watts per channel at 0.04 THD from 20-20K"
    I guess many of us are realizing that the THD spec really isn't something to look at anymore. Focus more on the sound quality of the receiver or amp, either by listening yourself, or by listening and asking around for comparisons and listening to those also. I listened to the receiver I just bought and it sounded better than my older amp, so sound quality was not an issue for me. I can't say it sounded better, because the better sound came from more power (110 watts per channel vs 50 watts per channel).
     
  10. KeithH

    KeithH Lead Actor

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    Mark, re-read my post. Where did I say that a lower THD necessarily explains the better quality of an amp? In fact, I included a qualifier to the contrary. Better amps often, but not always, have lower THD ratings. For example, compare the THD ratings of your garden-variety Best Buy $300-400 receivers to that of a Sony ES, Marantz, Denon, etc. units that sells for around $1000. The $1000 models generally have lower THDs. However, I think I made it very clear that one should not attribute the better sound to the lower THD. I indicated that my Sony ES receiver has a better amp section than the 'DB930 I owned previously. That along with better parts, better design, etc., explains the better sound. It is true, however, that the ES model has a lower THD rating than the DB model. Please read posts more carefully before jumping to (wrong) conclusions.
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  11. Matt Wallace

    Matt Wallace Second Unit

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    Mark,
    "06810" ... I'll forgive you for disagreeing with me, as that's the Zipcode on my birth certificate! NEXT TIME though... LOL! To each their own : )
    Matt
     
  12. Holadem

    Holadem Lead Actor

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    .
    [Edited last by Holadem on October 01, 2001 at 10:18 AM]
     
  13. Holadem

    Holadem Lead Actor

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    Mark,
    Keith's position was well written and crystal clear to me, yet you say almost exactly the same thing he said... and you insist that he is wrong? [​IMG]
    --
    Holadem
     
  14. John-D

    John-D Stunt Coordinator

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    Some THD figures..
    Bryston - around 0.007%
    Classe - around 0.03%
    Conrad Johnson < 1% (FET designs)
    Krell - around 0.03%
    Mark Levinson - around 0.3%
    McIntosh - around 0.005%
    Plinius - around 0.05%
    It's accepted that THD above 1% is audible.
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  15. GarryW

    GarryW Stunt Coordinator

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    So if a low THD is not of concern, are there ANY spec's that one should look for in a reciever, preamp, or amplifier? [​IMG]
    Can someone educate us here?
     
  16. Eugene Hsieh

    Eugene Hsieh Supporting Actor

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    I remember from the olden days that anything under 1% (not .1%) was difficult to discern, so it should not be a major consideration when under that number.
    That said, the numbers are not reliable anyway. Indeed for one of my machines it gives 0.7% and 0.05% depending on how the signal is being run through it. Furthermore, I find that boutique brands often have higher THD measurements than mid-range stuff. Does that mean they're crappier components, or just that the numbers are more honest for real world conditions?
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  17. John Di Lauro

    John Di Lauro Stunt Coordinator

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    While we're on this subject, what is the relationship between THD and speaker impedance? I've noticed that sometime specs give THD at both 8-ohm and 4-ohm loads, and the 4-ohm numbers are typically higher. It does not seem to be a linear relationship, either. Is this always true, and if so can anyone explain why?
     

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