Wattage Concern? Please clarify

Discussion in 'Archived Threads 2001-2004' started by Kris Coffin, Jun 22, 2002.

  1. Kris Coffin

    Kris Coffin Stunt Coordinator

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    I have done a bit of reading on this, and have a couple questions.

    The system I am setting up will have the 2 front channels running at 380 watts (Rotel RB-1090) and the center, rears and surrounds at 200 watts (Rotel RBM-1095) Will there be a sonic difference that is noticable between the fronts and the rest of the system? It is not to late to change my mind and get the RB-1080 which is 200 watts by 2, or 3 RB-1090's and run 380 watts on all 6 channels.

    My second concern is my rears and surrounds can handle 400 watts. So would running them with a Amp so close to the Speakers max power handling damage the speakers at high levels or peaks?

    And lastly, what would the benefit of running the system at 380 watts over 200 watts? How great a sonic difference? Enough to constitute the $2500 extra cost?

    Any help would be great, thanx.
     
  2. Bill Kane

    Bill Kane Screenwriter

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    Kris, Welcome to the Forum...

    I'd say at the outset you would have all the system power one wud ever need with these Rotels.

    The wattage game is easy to play, but pure watts are not the prime factor in a home system. What you have is power reserve -- what we call "headroom" or the capacity to handle sonic peaks and power draws upon our amp transformers and capacitors. It's something like a sports car with 300HP -- we're not gonna use that capability even half the time.

    Given typical listening levels, it's not unusual that a home amp will be using 10-12watts even at 75dB. Sonic difference betw 380W and 200W will not be easily apparent in this case, because we not running the system at its max in everyday operation.

    Usually, speaker wattage max ratings are less than a big amp's wattage max. This is better than the reverse. Underpowered speakers will result in the amp clipping at higher volume levels.

    You'll only damage your speakers if you turn the volume to max! 400W rears/surrounds is huge! Are these like Cerwin-Vegas? (OK, I now see they're DefTechs).

    Even Paradigm's biggest mains in Monitor Series are rated 180W max input coupled with amp power range of 15-250W.

    A good indication of a speaker's capability is its Sensitivity/Efficiency -- say 91dB and higher -- which demands less amplifier power. Now if you are running speakers that are rated 4ohm like MartinLogans (more power needed to drive) then the bigger amps are made for this combination.

    Rotel RB 1090 is rated 380Wx2 per chl at 8 ohms, I see.

    Your amp/speaker system as described wud be capable of filling a very large space!

    bill
     
  3. Kris Coffin

    Kris Coffin Stunt Coordinator

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    Thanx for the info Bill, much appreciated.

    I have a question about your response. What would be considered Max? You mentioned the sonic difference would not be readily noticeable unless I am at max. I will be using the system primarily just for movies as I watch very little TV. And I plan on cranking it up for most of the movie watching. I guess I am asking if it would be noticeable at say reference levels?

    BTW, I completly forgot to include what speakers I have.

    DefTech BP200tl Fronts w/15" 500w pwrd sub
    DefTech C/L/R 3000 Center w/10" 150w pwrd sub
    DefTech BPVX/P Rears and Surrounds w/2 6.5" 125w pwrd subs
     
  4. Bill Kane

    Bill Kane Screenwriter

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    Kris, these two monster amplifiers and heavy-duty bipolar floorstanders and surrounds as you have described would be considered a top end-of-the-line dream system for most people.

    Maybe end of career too -- pricing out at $10,900.

    I tried to indicate that most listening levels in home environment NO WAY approach these maximum rated outputs and speaker loads. This system would have beaucoup reserve capacity built in -- and IMHO overkill for DVD only. A wide range of music from classical to rock would sing on such a system.

    bill
     
  5. Dustin B

    Dustin B Producer

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  6. Vince Maskeeper

    Vince Maskeeper Producer

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    Kris,

    In addition to the advice you've gotten above- I wanted to chime in on this question. I have worked with speakers, day in and day out, for nearly 10 years. I have done some wattage levels that would scare you. I have never, not once- damaged a speaker driver from excessive wattage.

    I routinely put 1000watt amps on drivers rated for 500 watts, without issue. Power rarely damages speakers- it's distortion that is the undoing of drivers in 99 cases out of 100.

    When you put yourself in a situation where you are using the absolute max of an amplifier or of your preamp (usually a result of not having enough power, so you have to beat the piss out of your gear)-- you run the risk of clipping the amp or preamp (running out of headroom by pushing absolute maximum levels). This clipping causes the waves to be incomplete- and they "square" at the peaks- and this square waave will damage speakers much more easily than excessive power.

    So it's always better to have too much power- because this means you can feed your speakers CLEAN signal. When you skimp on amplifier wattage and find yourself pushing them real hard- this is where you run the greatest risk.

    -Vince
     

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