Power

Discussion in 'Archived Threads 2001-2004' started by JohnVB, Aug 20, 2002.

  1. JohnVB

    JohnVB Stunt Coordinator

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    I have heard from a few people now that a receiver with more power is better - that it will sound better even at lower volumes than a lower powered receiver. Is this right? If so, can someone explain why this is so?

    Thanks,

    - bones
     
  2. Paul Clarke

    Paul Clarke Supporting Actor

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    Because it takes a certain amount of power to fill a [certain sized] room with a certain amount of sound level. A lower powered receiver in the same space requires higher [receiver] volume level [setting] to achieve the same dB. The more a lower powered receiver/amp is stressed the more the sound character will change due to distortion of the signal. A higher powered receiver/amp can deliver the same signal at lower [receiver] volume [level setting] with less stress and achieve the same dB. It can also play at [a]lower volume [setting] with greater punch and clarity and at [a] higher volume [setting] with greater accuracy and less distortion.
    Whew! I hope this is clearer. :b
    Again...this is a short and sweet GENERAL STATEMENT and DOES NOT speak to the issue of whatever PARTICULAR receivers/amps may be in consideration. It does not address the fact that it requires a doubling of power to achieve a 3 dB increase. It does not address about a zillion other issues as well as can be seen from the following posts.
    Jeesh! Tough crowd! [​IMG]
     
  3. Yogi

    Yogi Screenwriter

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    Actually Paul, any receiver will require the SAME amount of watts to fill up a room to a certain SPL. The only difference is at what percentage of full power the receiver is operating at inorder to put out that amount of power. If your room requires 50Wx5 to be filled with reference level SPLs then a receiver that is rated at 55Wx5 will be operating at almost full power inorder to achieve reference SPLs. And we all know amplifiers become nonlinear at their extremes. So more than likely this receiver will be distorting/clipping in achieving 50Wx5. OTOH a receiver thats rated at 100w x 5 will still be in its linear operating range when putting out 50W x 5 and will sound composed and in control.

    Also even though the difference between a receiver rated at 80W/ch and another one rated at 120W/ch is only 2 db, the later has a better built power supply in order to achieve that extra 2db and that translates to better current delivery, woofer control etc. So even if using the same amounts of power in both cases (say at low volumes) you will still find the sound of the more powerful receiver to be more refined and composed. Also thats one of the reasons why separate amplification (of same rating) sounds better than the built-in amplification of a receiver even at low volumes.

    Hope that explains it.
     
  4. Saurav

    Saurav Cinematographer

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    I think that's what he meant. When he said "requires higher volume levels", I think he meant something like "will be at a higher position on the volume dial", not that the actual volume or SPL would be higher.
    Your explanation is a little clearer though [​IMG] IMO, of course.
     
  5. Paul Clarke

    Paul Clarke Supporting Actor

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    Sorry for any confusion. I was trying to keep it less technical from my read of the initial post. And yes, thanks Saurav, for being able to interpret my sloppy terminology...that's just what I meant.
    Isn't it funny how one word here or there can cascade into a waterfall?[​IMG]
     
  6. Rob Rodier

    Rob Rodier Supporting Actor

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    So does thatmean that a 100 watt amp will sound better than a 50?

    -rob
     
  7. Robert Tonkin

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    Speaking of receivers sounding better at different levels... I think I now understand the difference between two receivers that are both rated.. say 75 watts. One may be "pusing the high distortion envelope" at 75 watts while the other can deliver 75 watts much "cleaner".

    So... Is the THD rating of the two, say .3 for the first, and .05 for the second represent the same "benchmark" at 75 watts or... is this where we have the breakdown in stats. Meaning even the THD ratings cannot be compared apples to apples even at 75 watts. OR is it even the THD numbers I should be comparing?

    I hope I made that request clear.

    Thanks
     
  8. JohnVB

    JohnVB Stunt Coordinator

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    Thanks all for your replies. It makes sense to me now [​IMG].
    What's the general rule of thumb for Power on A/V Receivers. Should I consider only units with 100 or more Watts/channel?
    Some A/V Recievers have "fully discrete" amplification. I'm assuming that this means there's a smaller amplifier circuit for each channel/speaker, rather than one honkin' amplifier for all of them. Can you hear a big difference between such an amp and one that doesn't have "fully discrete" amplification?
    - bones
     
  9. Saurav

    Saurav Cinematographer

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    I think THD is a load of BS. Tests have shown that people cannot hear THD below something like 1%, and all modern SS receivers have THD below 1%. So, it is completely irrelevant whether the receiver says .05% or .0005%, the difference is almost certainly inaudible.

    What is important is looking at whether the power ratings are for the full frequency range or for a single frequency (it's easier to quote a higher power number if you only measure it at a single frequency), and if the power rating is for all channels driven simultaneously, or with a single channel being driven (this should be obvious, an amp that produces 100W when driving 1 speaker probably won't produce 100W when driving 5 speakers in parallel).

     
  10. Jonathan Smith

    Jonathan Smith Stunt Coordinator

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  11. Rob Rodier

    Rob Rodier Supporting Actor

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  12. Saurav

    Saurav Cinematographer

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  13. Rob Rodier

    Rob Rodier Supporting Actor

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  14. Paul Clarke

    Paul Clarke Supporting Actor

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    Rob Rodier Supporting Actor

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  16. Yogi

    Yogi Screenwriter

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    Agree with Saurav that THD is BS and over inflated. My Proceed amp with 0.1% THD sounds much much better than my 3802 with 0.05% THD. I never pay attention to this spec.

    Also, all watts are not equal (in quality that is). You will hear a number of members in this forum swear by a parasound 855 making a night and day difference in sound from their 3802's internal amps, even though the 3802 is rated 25W more than the 855.

    Also most modern day speakers that have around 90 db sensitivity would infact require about 100W/ch to play at reference levels in a moderately sized room. With more/less sensitivity the power requirement will change.
     
  17. ErichH

    ErichH Screenwriter

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    You guys are talkin' the right stuff. A watt in a Denon or Onkyo is not the same as a watt in a Bryston. Yugo or BMW !

    Eric
     
  18. Claude M

    Claude M Stunt Coordinator

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    Here is the less technical answer: my 1991 plymouth sundance can go 85 MPH on the highway but it sounds and feels like it's going to blow up. At 50 MPH it feels and rides much better, but it's still using half it's power to do so (say half, just to give a number to get the idea accross). Now a porsche can go 80MPH and the ride will be smooth. AT 50MPH it's using a smaller fraction of it's total power than my plymouth but the ride is still much better than the little sundance. The point is the larger amp/engine has more power in reserve at lower volume/speeds.
     
  19. Paul Clarke

    Paul Clarke Supporting Actor

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    I've decided to go back and edit my first post with clearer terminology so maybe we can finish off this thread once and for all. :b
     
  20. Yogi

    Yogi Screenwriter

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    Paul, wow nice edit. The directors edition, much clearer and precise. Sorry I didnt mean to pick on your post. Just wanted to clarify even though I had the feeling that you were getting at the same thing. In any case this should put this thread to rest.

    RIP (The thread that is)
     

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