Power ratings used by manufactures

Discussion in 'Archived Threads 2001-2004' started by anthony_b, Sep 6, 2002.

  1. anthony_b

    anthony_b Screenwriter

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    I have a simple question... When manufactures use specs as:
    100w x 6, is that the power rating with all channels driven at the same time ? or is it the power rating they are capable of individually ?....I'm afraid of buying a reciever that would actually put out 30w/per channel when the specs could mislead you stating 100w x6 !!
     
  2. Paul Clarke

    Paul Clarke Supporting Actor

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    Anthony,

    You are correct in your suspicion. Unless they say otherwise, most multi-channel power listings are for channels driven individually.

    Here is a rule of thumb: If the item you are researching, say on the web, is not listed as X amount of power at x Ohm at 20Hz-20kHz all channels driven...then it is not a true multi-channel listing. It may be perfectly legal from the standpoint of regulations...but it means bupkus in terms of honest evaluation from the power standpoint.

    Now having said that, power evaluation is only one element in the decision making process. Many underpowered receivers still have good sound. I just wouldn't want to ask too much from any of them.

    If you're interested in real world power:
    Always look for full bandwidth rating
    Always look for the actual expression 'all channels driven' (or at least more than 1 or 2)
     
  3. Steve Marsh

    Steve Marsh Stunt Coordinator

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    Yes Even higher end manufacturers rate the product this way. Look at the Marantz x200 line for ex. The actual power these units are putting out is nothing like thier rating when all channels are driven as they only rate into 1.
     
  4. anthony_b

    anthony_b Screenwriter

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    That's scary....I'm really going to have to do some research before laying down my cash..

    I'm considering the following three recievers:

    HK 520
    Denon 2802
    Marantz 6200

    I currently own the ONKYO 575X
     
  5. Chris PC

    Chris PC Producer

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    Wrong. If you look at the Marantz owners manual it clearly states 105 watts per channel into 3 channels driven simultaneously.
     
  6. Steve Marsh

    Steve Marsh Stunt Coordinator

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    Well it seems as if this post is getting results.
    In the Marantz manual(7200) under specifications it shows the power ratings for front, center and surround but nowhere does it say all channels driven simutaneously. That is the point. If it does not say then it prob is not. This is deceptive but common practice.
    Anyone who owns an x200 series RX knows that it seems a little weak on multichannel (as far as power is concerned) and this is the reason.
    If you check the ratings supplied by independent testing (sound and vision) you will find that the 7200 puts out something like 30 w/chann all driven. Marantz claimed the test unit was defective but TO MY KNOWLEGE never sent another unit or got a retraction or retest from S&V.
    PLEASE IF I AM WRONG ABOUT THE RETEST OR RETRACTION LINK OR CORRECT ME WITH PROOF.
    Steve
     
  7. Pablo Abularach

    Pablo Abularach Supporting Actor

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  8. Bob McElfresh

    Bob McElfresh Producer

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    The Yamaha numbers are usually very accurate as well. They are good about listing separate specs for 2-channel and 5 channel. They also specify:

    - 8 ohms resistive load
    - Frequency from 20-20,000 hz
    - All channels driven

    They are usually so detailed, we have to explain why each is important.
     
  9. John Garcia

    John Garcia Executive Producer

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    I've said this a number of times, but going to say it again. What matters is what you actually get out of the receiver. I believe my EARS. So when I have a question, I will go out an actually listen to a particular receiver. I will turn it up and see how it sounds vs the specs of the speakers it is hooked to, and THAT tells me if the manufacturer is full of BS or not. Manufacturer's numbers do tend to be optimistic, but I also find that to be almost useless marketing gibberish.

    I don't dispute the test results of the 7200, but I own a 6200 and have absolutely no issue with power, even at rediculous, uncomfortable levels without distortion. In most cases, I can't listen at ref calibrated levels in a fairly large room, it's just too loud. So it only put out ~37wpc, most people don't realisticly need more than that to power an average system to respectable SPLs.
     
  10. Steve Marsh

    Steve Marsh Stunt Coordinator

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    John
    I will not dispute the fact that 37WPC is sufficient for you and indeed most people. The fact remains that the thread starter wanted to know how the manufacturers rate the product. MOST manufactures do not rate all channels driven because this would substatially lower the numbers and the vast majority of consumers would not understand the difference. They would only see lower numbers.
    FYI I have tried the Marantz 7200 and yes it does produce loud volumes but I feel it is pushing less power than the specs lead people to believe. For me to get ref levels out of that machine the volume would need to be up at about 85-90% of max. I always feel that it is unwise to use a reciever at levels this close to its max.
    But ultimately you are right. The unit has enough power to create volumes higher than almost anyone would listen to so it boils down to using your EARS and decieding if it is enough foe you.
     
  11. John Garcia

    John Garcia Executive Producer

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    I tend to listen to most movies and music around -20 on the dial, with ref cal at -8, and a max of +15. For me, this is about 70% of output, leaving me what I feel is sufficient headroom for most movies even at very loud levels. I have pushed it to the point where I've heard strain in the system, and eventually I will most likely add external amplification, but I have found that for day to day listening, the amp section in this unit does a very respectable job.

    Another key factor in how that amplification is made use of is the speakers themselves. If you have speakers that like/require plenty of power to play clear and loud, you may very well strain most integrated amps at this price point (~$700) I am running Paradigm all around - Monitor 5s, CC270, and a trio of Titans out back. All are fairly high sensitivity and are set to small for movies. This setup gives me more than enough volume for my needs. Speakers and how much power they will need to achieve your desired volumes, need to be factored in when choosing a receiver/amp.

    I agree that it is unwise to use an amplifier at 80%+ of it's capability. This will either cause the eventual failure of the amp or damage speakeres because you WILL reach distortion levels.
     
  12. Steve Marsh

    Steve Marsh Stunt Coordinator

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    Obviously your room is smaller than mine as ref (85dB on the test tone) was over 0 on the 7200 at my place. I am using Paradigm Studio ref 60 V2, Studio CC V2, Paradigm 3SE surrounds and Paradigm 3SE surround centers as well as a Sevo 15 sub.
     
  13. itai

    itai Stunt Coordinator

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    so how about those dedicated multicahnnel amps out there?
    are they also stated powering one ch???
    is a sherbourn 5x200 real or fake too? [​IMG] [​IMG]
     
  14. John Garcia

    John Garcia Executive Producer

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    Steve, just with the 60s and the Studio CC, you were probably pushing the limit of the amp. This is exactly what I was referring to with respect to power (and I had the Studios in mind when I typed that), and I don't feel the 6200/7200 can effectively power the 60s. These speakers simply need more power than that.

    My friend has an SR19EX driving Studio 40s, CC, and in wall surrounds, and it can pretty much keep up with them, but at loud levels during heavy passages, I have heard it get a bit thin (no distortion).
     
  15. JohnDG

    JohnDG Stunt Coordinator

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  16. DanaA

    DanaA Screenwriter

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    I think the dedicated amps are another story altogether. My amp is rated at 140 watts/channel, but was tested at 157 watts/channel, all channels driven simultaneously. My receiver, rated at 100 watts per channel X 5, tested out, if I recall correctly, at 46 watts/channel with all 5 driven simultaneously.
     
  17. JackS

    JackS Supporting Actor

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    Anthony- A simple solution may be to go ahead with the purchase of a receiver that would be your choice if internal amps were completely out of the equation. You now own the processor you like and with the addition of a small two channel amp (new or used) to drive the two mains, all the power that would be needed in any reasonably sized room. This quasi seperates solution has gained quite a large following on the forum, and just for the reasons you have already noted. This solution works well for reasons of economy and also power that can be trusted.
     
  18. TerryHenson

    TerryHenson Agent

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    To get a rough (very rough) idea on how well your receiver might stack up to it's advertised rating is to check the UL or CAS rating of it's power supply on the rear of the unit.

    For instance my Yamaha is advertised at 120w x 6, but the stated max power is 500w for the power supply. Even with capacitance there's no way my receiver is going to supply 720w or 120wpc all channels driven.

    So minus overhead, I'd be lucky to see 400w going to my speakers continuous, but that's still enough juice to provide excellent sound at very loud levels.
     
  19. Marty Neudel

    Marty Neudel Stunt Coordinator

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    There's another area that has to be looked at: distortion. Most specs are for thd and imd with a 1kHz signal. Distortion at 12kHz can be considerably higher; and at 20Hz, distortion could be over 2%. Distortion figures should be listed for a 20-20k signal @ rated power level with all channels driven; yet, I know of only 1 manufacturer who states specs this way.

    Marty
     
  20. Craig_Kg

    Craig_Kg Supporting Actor

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    Most receivers will show full bandwidth (20Hz-20kHz with THD) specifications for stereo mode into 6 or 8 ohms. This is almost always an accurate guide of how all the amplifier sections perform while the power supply has not saturated since they are identical.

    Then look at the power supply rating and take off about 100W or 150W (for powering circuitry and parasitic losses) as suggested by TerryHenson to get an idea of the maximum power that can be supplied in total.
     

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