how to drive 200w speakers efficiently

Discussion in 'Archived Threads 2001-2004' started by DaveRana, Jan 7, 2003.

  1. DaveRana

    DaveRana Agent

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    Please bear with me if my terminology is obscure but this is what I want to set up:
    Assuming I have a pair of main L/R speakers rated at 200w in a home theater setup and I also listen to music in stereo mode often, can I get a 5.1 A/V Receiver that is 100w x 5 (total 500w)where I can "combine" 2 channels together to give me 200w each to drive the front L/R speakers alone?
    Any help is appreciated [​IMG]
     
  2. ColinM

    ColinM Cinematographer

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    That's not really how it works -

    The 200 watts means that's the juice the electronics (speaker) can soak up before they fry, in very loose terms. Mor than that for too long will burn up the crossover or voice coils.

    Usually, in fact, you need less than 15 - 20 watts anyway. Look at the efficiency rating of your speakers. Like 1 watt gives you 90 dB for example. That's loud! Double wattage = +3 db, so 2w = 93, 4w = 96, etc.

    Again, very generally speaking, but you get the idea.

    - CM
     
  3. Bob McElfresh

    Bob McElfresh Producer

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    Let me re-phrase the question:
    You somehow want to combine 2 speaker level outputs at 100 watts each to give you a total of 200 watts to your speakers that are rated to 200 watts?
    Or are you trying to buy a second receiver, feed the L/R signals from the first and let the second drive only the L/R speakers?
    Uhhhh... both are kind of bad ideas.
    You should NOT look at the power limit on a speaker and try to provide amplification to this point.
    (This would be like buying speed-rated tires, say 120 mph, and always trying to drive at 120 mph.)
    Think of the 200 watt rating as a "Dont Go Beyond Here" type of thing. Not a "Give me this much power".
    In truth: on average your speakers are using about 3-10 watts of power. (No, I'm not kidding.)
    But because of the physics and the way we hear sound, to get a increase in sound you must double the power. So there are moments in a movie where you do output 80-100 watts. But this is for a few seconds.
    If you really want to add more power to those L/R speakers:
    Does your receiver have pre-outs? RCA plugs for the L/R speaker outputs? These are so you can add an outboard amplifier. Start reading the magazines or hit the "Receivers/Separates" fourm for info. These "boxs" come in 1 channel, 2 channel, 5 channel, etc.
    A nice thing for you to do would be to add 2 "Mono-Blocks" and use one each to drive your L/R speaker. Hit eBay to see if you can find some used to "get your feet wet" into the world of separates.
    Does this help?
     
  4. Ted Lee

    Ted Lee Lead Actor

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    i think he's asking if a 5.1 receiver (at 100w/ch) will somehow "combine the internal amps" so that when he's playing it in stereo (2-ch) mode, the total wattage to each channel will increase (because the "unused" channels aren't being amplified).

    afaik, that doesn't happen, but i'm not 100% sure on that.
     
  5. DaveRana

    DaveRana Agent

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    ColinM,
    Thanks for your reply. I have no clue what the efficiency rating of my speakers is. I have a pair of 5 yr old b&w 604s and their "Power Handling" is 25w-200w into 8 ohms on unclipped programme. So now, shouldn't I be looking for some receiver/amp that will deliver at least 150w for the channels that power the 604s?

    Bob,
    Thanks for your reply. What I'm trying to do is this:

    1. Go with ONE integrated receiver that does it all. I can't go into separates at this point in time. $ and space constraints.

    2. I don't have any other equipment yet, besides a pair of b&w DM604s sitting on the floor. I'm trying to get an AVR that will work in a home theater setup (no problem here) but should also have enough oomph to drive JUST the 604s for stereo music. I am no highfalutin audiophile (yet..hehe) but I sure can discern good sound from bad. My worry is that if I get some 100wx5 AVR and turn the volume knob past the 1/3 mark when in stereo mode, I'm going to get hiss and distortion - something I probably won't get if the channel is rated at a 150w. No? Yes? Maybe?

    Thanks again!

    PS: I don't want to spend more than $600 on the AVR either (new OR used)
     
  6. DaveRana

    DaveRana Agent

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    Ted, You hit the nail on the head [​IMG] After a 30-min holding wait with Onkyo Tech Help, they confirmed that this can't be done. So now....I either want to get an AVR that pumps 150w on two channels and 50-100w to the other three channels (is THIS possible?), or just get a 100wx5 AVR and later, get a 2-channel 150w amp to drive the fronts.....I dunno....!!
     
  7. Ted Lee

    Ted Lee Lead Actor

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    dave -
    one thing to consider is not just the amp's wattage rating, but how well the other spec's look. specifically check to see what the frequency response is and what the "thd" (total harmonic distortion) is.
    you want a receiver that can cover the range of 20hz (bass) to 20khz (treble). you want a receiver with a low thd. i'm not really up on my specs these days, but i think something under 1.0% is pretty decent. most are somewhere around .05 i think.
    finally, think of a receiver's amp in this way. yes, the receiver may be able to crank out 150w/ch, but how good will it sound? like you said, after turning the know 1/3rd of the way, it'll sound distorted - yes you're cranking 150 watts...but it's all distorted sound!
    in my opinion, a well designed receiver will sound better at lower volumes - so you won't have to turn it up as high to hear everything.
    within your budget, and your emphasis on clean amps, i'd check out either harmon kardon or outlaw audio (www.outlawaudio.com). they both have pretty well regarded amp stages.
    good luck! let us know if you have any other questions!
     
  8. DaveRana

    DaveRana Agent

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    Ted,
    You're right but please bear with me...

    Let's say I have two AVRS:

    AVR#1: 20hz - 20khz, < 0.5% THD, 80W x 5

    AVR#2: 20hz - 20khz, < 0.5% THD, 150W x 5

    Am I right in thinking that AVR#1 will strain to deliver clean music past the half-way mark on the volume dial but to achieve the same decibel levels, AVR#2 will provide a much cleaner sound? I don't blast the music always but sometimes I like to pump it up loud, when listening to club music if I'm throwing a party, etc.

    Is there something else I should know about? BTW, I just looked at specs on Denon, Onkyo, Marantz etc...they ALL have THD less than 0.8 and freq range 20hz-20khz...except Onkyo (model TX-DS787) which boasts of 10hz-100khz. How does that figure?!
     
  9. Ted Lee

    Ted Lee Lead Actor

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    oh yeah...you're right.
    all things being equal, i would also go for the higher wattage amp.
    i'm not sure why the onkyo has a broader range. i guess they think they're receiver is "all that". i have onkyo gear myself and am pretty happy with it.
    i should add (as a final qualification) that you should put some faith (but not all) into the specs of the gear.
    try to listen to the receiver, touch the buttons, check out the remote, and (of course) evaluate the features. ultimately those things will have more impact on your day-to-day usage of the receiver than those specs anyway. [​IMG]
     
  10. DaveRana

    DaveRana Agent

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    Ted,
    I looked at Outlaw 1050 and liked what I saw, so I ordered it. It should arrive in a few days. I'm just crossing my fingers and hoping it's able to drive my DM604s adequately. If not, I'll just get a separate 2-channel 150w amp later on. Can't wait to get it all juiced up :)
     
  11. Ted Lee

    Ted Lee Lead Actor

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    rockin' choice! [​IMG] i'm totally jealous.
    although i have no personal experience with the 1050, i know it's very well regarded. you should do a search here too...i bet you'll be happy with what you read.
    i even think one of the two owners here (ron or parker) has one themselves.
    once you get it, i would be very curious as to your impression. if you remember, post your thoughts!
    congratulations! [​IMG]
     
  12. DaveRana

    DaveRana Agent

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    Ted,
    If everything works out well, I gotta thank YOU coz you suggested the 1050 [​IMG] Until then, I hadn't even heard of the Outlaw and was busy looking into the usuals - NAD, Marantz, Onkyo, Denon etc. I'll most definitely post my feedback once the 1050 arrives and I have everything juiced up [​IMG]
     
  13. Ted Lee

    Ted Lee Lead Actor

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    anytime dave! glad i can help...
     

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