Amp.power vs speaker power.

 

Bronze Member
Username: Subabu2002

Erode,, Tamil nadu,i... India

Post Number: 29
Registered: Apr-04
hi all,

some one says,equal of power amp and speaker(100watts amp with 100watts speaker)does not produce good sound as compared with low power amp with high power speaker.(80 watts amp and 100 watts speaker).

is it true??

thanks
suresh babu.
 

Silver Member
Username: Frank_abela

Berkshire UK

Post Number: 459
Registered: Sep-04
It could be true, and then again it could not. The fact is that power ratings simply give you an indication of how much power an amp can develop and how much power a speaker can take.

Note that power ratings are dependant on many factors. For example an amplifier might develop 30 watts into an 8 ohm speaker, but 45 watts into a 4 ohm speaker. (These are typical numbers for a good amp.) So you can't just look at watts and expect to understand how the combination will sound. The only true thing is that if you try to drive a speaker with an amplifier which isn't powerful enough, the amplifier will distort (clip) and could cause damage to the speaker, but this isn't very helpful since the power rating depends on so many things, particularly speaker impedance (4 or 8 ohms typically) and speaker sensitivity (the average is 87db/w/m).

regards,
Frank.
 

Silver Member
Username: Petergalbraith

Rimouski, Quebec Canada

Post Number: 357
Registered: Feb-04
I'll ony add that there's hardly a difference between 80W and 100W, certainly nothing to worry about (1 dB actually).

Power requirements are exponential and not linear. You may blast your speakers with peaks of 100W now and then, but it's likely that most of the time you are feeding 1W to 10W or even less. I was watching TV quietly last night at -50dB on the volume dial. Since my amp is only 55W per channel, that corresponds to something like 0.0005W !
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 3484
Registered: May-04


Good Grief, Charly Brown! SPEAKERS DON'T GOT NO WATTS!!!
 

Silver Member
Username: Petergalbraith

Rimouski, Quebec Canada

Post Number: 361
Registered: Feb-04
Good Grief, Charly Brown! SPEAKERS DON'T GOT NO WATTS!!!

Huh?

Surely they have maximum power handling.
 

Silver Member
Username: Kano

Post Number: 451
Registered: Oct-04
I agree with Jan, the maximum power handling of the speaker means VERY little in application. Unless in extreme differences such as pairing a 200W power amp with speakers spec'd for a maximum of 60W, you will not have a problem.

If a speaker is rated to handle a max of 100W, you won't have a problem pairing it with any receiver. Even if the receiver has a max output of 120W per channel, the chances of ever reaching 120W even into one speaker is low.

If you start hearing distortion, turn it down.

The statement that the max power handling of a speaker changes how it sounds is nonsense, while this may be true in one case, there will be another dozen cases that disprove it.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 3488
Registered: May-04


Peter - Here's how I used to describe speaker "wattages".

A good friend once had a Mitsubishi coupe with the early computer devices that "spoke" to the driver in a very attractive Oriental female's voice. As with Japanese receivers, Mitsibishi automobiles were famous for the features they included. One of these features was an "Instantaneous Gasoline Mileage Calculator". Push the button and the voice would give you the moment by moment estimated mileage you could expect to see when you calculated at the next fill up.

On a trip to Fort Worth, Pete hit the button and at 55 m.p.h. on flat terrain, the voice indicated 25 m.p.g. Pete pushed the peddle down and as we crested a good size hill we were going about 90 m.p.h. On the way down the hill Pete lifted his foot from the accelerator, went into a coast and after a moment hit the magic button again.

697 miles per gallon!!! From then on, Pete couldn't resist playing games with that little voice.


Yes, speakers have a maximum power handling. But the numbers are only relative to the moment the speaker stops working from too much juice. There is a large difference between 1kHz at 100 watts and 30Hz at 100 watts. There is an even larger difference between 30Hz at 100 watts that begins slowly and fades out as opposed to a kick drum that asks a 100 watt peak be delivered instantaneously. Then there is the difference between a kick drum and 30Hz that lasts for two minutes at 100 watts. And, just to make it interesting, many tweeters will go up in smoke if you feed them more than a few watts.

But in the strictest sense, since there are no active components in a speaker, speakers got no watts.


 

Silver Member
Username: Petergalbraith

Rimouski, Quebec Canada

Post Number: 362
Registered: Feb-04
Jan,

I agree with everything you said except for (because) there are no active components in a speaker, speakers got no watts only because in the strictest sense, they have a maximum load capacity over which you will either run out of driver excursion or burn out a coil. But I agree that it's rarely a useful spec.

But I wouldn't pump in 100W into my tiny PC speakers! :-)
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 3494
Registered: May-04


No, I wouldn't run my car into a brick wall at 100 m.p.h. either. No matter what that female voice says. A little common sense when it comes to not blowing up speakers goes a long way.





 

Silver Member
Username: Petergalbraith

Rimouski, Quebec Canada

Post Number: 363
Registered: Feb-04
:-)
 

New member
Username: Biochi

Post Number: 3
Registered: Apr-05
Hi:
A new member who knows nothing just learned a lot from your exchanges. But if someone could provide an answer to my puzzel I'd appreciate it: I have (4) 4 OHM 25 Watt Shakers/Transponders that I have installed in a massage table for a research project to see how people react to specific low frequency tactile resonance as they relax. The only amp I have available is 125 watts per channel or 350 watts bridged with impedence of 8 to 16 OHMs for Channel A + B or bridged. Stereo is not a factor since all shakers will receive the same input. My question is how to wire them for optimum output. Should they all be in series to the bridged output? Or each seperate as in 2 per each channel with one on the right and one on the left? Or 2 sets of 2 in series and only using Channel A.
Thanks in advance for your help.
Ted
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 3500
Registered: May-04
2 sets of 2 in series and only using Channel A.
 

New member
Username: Biochi

Post Number: 4
Registered: Apr-05
Thank you very much Jan.
Ted
www.BioChi.com
 

ddog
Unregistered guest
i am considering upgrading my mirage 650 speakers. they just don't seem to be exciting me. primarily just listening to cd's (rock, folk, blues, etc). powered with onkyo m.501, p.301 combo. Any speaker insight or thoughts would be appreciated.
paradign studio 40's?
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