Question How much power for I need?

Discussion in 'AV Pre-Amp/Processors & Power Amps' started by grahamricho, May 7, 2019.

  1. grahamricho

    grahamricho
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    Still looking to replacing my power amps and thinking of the nord acoustics multi channel ones. My surround speakers are 94db and front 3 speakers 97db.
    I've decided on the 200 watt hypex ncore ones for surround a 8 channel version.
    For my fronts I could get the same 200 watts in a 3 channel version or do I go for the 500 watt version for my fronts? On paper my fronts been 97db need around 32 watts to reach reference level. Would I gain anything? Or just get 11 matching channels?
     
  2. PhilCTTE

    PhilCTTE
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    The Nord amps look great and the reviews look good. I run a separate power for the front three and multi channel amp for the remaining 8. Anthem MCA 325 and an Onkyo PA-MC5001 for the 8. Important to match the front three imho. The Anthem has a higher output for LCR which is where you need the extra oomph
     
  3. IWC Dopplel

    IWC Dopplel
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    I agree that the front LCR are the most important for amplification needs. Probably best to stick to the same range as you would with speakers

    But I can say that if you have 97db sensitivity you will be very uncomfortable with an average of 32w per channel driving them (unless you are in a cinema sized room) and even then...
     
  4. Ringnut

    Ringnut
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    I have 300wpc @ 8 Ohms via an ATi P.A. into 94db efficiency speakers (mains and surrounds) and that works just fine. :thumbsup:
     
  5. grahamricho

    grahamricho
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    Thanks but on my calculations on 94db speakers you need 32 watts to get them to 115db? So is 300 watt excessive? There is a point where it seems pointless. ?

    I went from Bryston 9bsst @ 140 watt per channel to Bryston 7bsst @ 600 watt per channel and could not tell the difference, a £12,000 upgrade if I'd bought new. Everybody on a hifi forum told me how it would grip my speakers more, but it was a load of bull. I had to get off the hifi upgrade train..
     
  6. barnitto

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    I agree with the sentiment but I found a big difference going from a 50w naim power amp to a 200w ATI. Sounds like you hit the brick wall of diminishing returns with your Bryson kit...

    150-300w would seem to give you more than enough ‘headroom’ as they say
     
  7. barnitto

    barnitto
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    That is such a “hifi” term...what does it even mean :D
     
  8. Ringnut

    Ringnut
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    Then

    These two quotes seem illogical. o_O

    Firstly 115db is reference for a subwoofer not a main. ;) Secondly 300wpc for a 94db efficient speaker is actually less OTT than 200wpc for a 97db efficient speaker. So you only really need around 20wpc then - good luck with that. :)
     
  9. grahamricho

    grahamricho
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    Im just quoting what people tell me, but then i get the calculator out and think do i really need that much? hence asking the question.

    Also do Atmos and surround ever get that loud need loads of power on a soundtrack

    Im using Bryston 9 bsst for my fronts at present from my hifi days when my speakers were not as efficient.

    I believe also that the Nord amps are measured differently than normal amps so the 200 watt is peak or RMS which ever way, it cooks the figures a bit?

    So what is reference for a main speaker?
     
  10. Ringnut

    Ringnut
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    105db is considered 'Reference' at the MLP, i.e. the peak level required for all channels to meet in any setup, so any amplification should be capable of meeting that without distortion or clipping. This seems to suggest that your original choice was about right given a 4 mtr listenting distance from your mains. If you sit closer than that then this can be reduced.

    Your surrounds are less efficient but then again are likely to be a little closer, even more so in the case of any Atmos speakers. Room gain will also have an effect on these figures.

    I believe Dolby requires all channels to be capable of the same peak levels.

    Amp power required.jpg

    As you can see from my signature my policy is always that it is far better to have a little too much, rather than too little, power when it comes to amplifiers.

    Damage to speakers is more likely to be caused from having an underpowered amp due to clipping than being over-driven from having too powerful an amp AIUI. At the end of the day it is up to you, but amps tend to stay with you a long time and you may not always have such efficient speakers. Your choice in the end.
     
  11. grahamricho

    grahamricho
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    So why does a quality amp drive speakers better?
    My Bryston 9bsst never misses a beat, but on paper I've had more powerful amps but cheaper and they seem to struggle?
     
  12. jason shep

    jason shep
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    Hi
    I believe it has a lot to do with the quality/ability to supply current, of the power supply in the amplifier, especially if your speakers present an awkward load.
    For example, I briefly owned a Rotel multi channel ICEpower amp rated at 250W per channel, it sounded completely gutless driving my 4ohm speakers, even my ancient Arcam avr100 rated at something like 50wpc drove the speakers much better.
     
  13. IWC Dopplel

    IWC Dopplel
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    I still think that db per speaker will be misleading, unless you are listening to one speaker only. If you had a 5.1 set up then moved to a 9.4.6 set up then the db per speaker calc would be a bit meaningless. A good point though regarding your sitting distance. With 5.2 and relatively low efficiency speakers (My fronts are 88 db and 4 Ohm) I have no volume problems at all with 4 x 135W monoblock amplifiers driving the 4 Ohm fronts. Real world amplifiers driven hard can behave differently. If I recall some well designed amplifiers can have very high peak current delivery and cope much better when stretched. Bryston / Naim and a few others have very good current delivery and carefully consider damping factors and so on.

    Could you demo options and see when enough is enough (But power amps do sound different, so it's more than just power)
     
  14. grahamricho

    grahamricho
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    Hi why is it misleading with the more speakers you have? thanks
     
  15. IWC Dopplel

    IWC Dopplel
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    The more speakers you have the more dB you will have in one room. 15 speakers played at 75 dB each will be considerably more when played back unless the processor adjusts in which case they will be playing individually be say 65 dB. Obviously this depends on the positioning but given Atmos is object based most of the time more than one speaker will be playing
     
  16. IWC Dopplel

    IWC Dopplel
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    The more you have the more will be playing
     

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