Amp Power & Speaker

[Jeremy]

Hey, just like to know how much amplifer power can a speaker take so as not to damage the driver ?

I heard that higher power wattage is better for a speaker. Example amplifer with more than 100W per channel at 8 ohm can drive a speaker rated at 100W 8 ohms more efficiently.

If that's so, how much amplifer power should a speaker ( example 100W 8 ohms ) be driven that will not damage its driver ? Is there a calculating method ?

Thanks.

[markw]

The speaker ratings are virtually meangless and most revceiver's power ratings are highly exaggerated in order to look good on paper.

You can safely drive any speaker with any amplifier as long as you use common sense and remember the main rule in hi fi, which is: "If it sounds bad, turn it down ...NOW!"

When something starts to sound bad, it's either the speaker or the amp complaining. The amp may be driven well into clipping (not good) or the speaker may be trying to move more air than it's capable of safely doing. In either case, the speaker won't last too long.

I've driven teeney minimus 7's (rated @ 40 watts) with a Marantz 2270 (rated at 70 wpc but actually more like 90 in the midrange) to satisfying, but sane, levels for quite a while without damage.

Of course, if I were to be stoopid enough to try to boost the bass to wall shaking levels and/or try to achieve room filling levels I'd have a problem but, using the above rule, all has been well.

[JohnMichael]

More tweeters are destroyed by a low powered solid state amp clipping long term than a powerful amp giving undistorted power.

[N. Abstentia]

Impossible to answer that question. Even if you got it down to getting someone to say "you should be running a 50 watt amp to your speaker" that's useless. There's a big difference in cheap Sony/Yamaha/JVC 50 watt amps and nice Aragon/Anthem/McIntosh 50 watt amps. The cheap Sony/Yammy/JVC will send lots of distortion along with the power so the speaker actually won't handle as much because of the distortion. Howver the higher end amps will send nothing but clean power so they will actually handle more than the 50 watts.

Plus the cheaper amps are not rated the same way as the high end amps, so 50 watts from a cheap amp is not the same as 50 watts from a high end amp.

It also depends on how the speaker and crossover are rated. So, as I said...impossible to answer simply.

[grigore]

Impossible to answer that question. Even if you got it down to getting someone to say "you should be running a 50 watt amp to your speaker" that's useless. There's a big difference in cheap Sony/Yamaha/JVC 50 watt amps and nice Aragon/Anthem/McIntosh 50 watt amps. The cheap Sony/Yammy/JVC will send lots of distortion along with the power so the speaker actually won't handle as much because of the distortion. Howver the higher end amps will send nothing but clean power so they will actually handle more than the 50 watts.

Plus the cheaper amps are not rated the same way as the high end amps, so 50 watts from a cheap amp is not the same as 50 watts from a high end amp.

It also depends on how the speaker and crossover are rated. So, as I said...impossible to answer simply.

Very good answer too!

[kexodusc]

I just posted this in another thread, but it's worth reading:

The max power handling rating generally refers to the voice coils ability to absorb electrical energy without damage...bigger coils handle more. This figure is quoted RMS so in reality, the musical power rating is much, much higher (which is part of the reason why you can drive more power to a speaker than its rating).

The problems begin at the low frequencies though. Excursion demands increase the lower you go, and power handling mechanically drops really fast as you approach the frequency of resonance of the driver. For most 5 or 6" woofers I've seen, this happens rougly in the 30-50Hz region. 8" woofers handle power a bit better, and subwoofers better still. When excursion reaches max, you can hear lead slap and your woofer can bottom out. Physical damage at this happens at this point. I should add, this can occur at significantly lower power levels than the speaker's ratings, sometimes just a few watts. This is one reason why it's a good idea to set speakers to "SMALL" (even on floorstanders) if you have a subwoofer connected to your receiver.

The minimum power rating is to protect tweeters from poor amplifiers. Good SET's and SS's won't feed much distortion, but poor ones will. You get a lot of upper harmonics added to the tweeters load, and the power to the tweeter soars from the normal miliwatt range to full watt figures - during peaks you can easily damage the tweeter. This is bad.

Clean power, undistorted, not clipped is good and most speakers can handle more than their ratings when fed the good stuff, just don't push it.

[grigore]

More tweeters are destroyed by a low powered solid state amp clipping long term than a powerful amp giving undistorted power.

You're right too!

[kexodusc]

More tweeters are destroyed by a low powered solid state amp clipping long term than a powerful amp giving undistorted power.

In my experience, most tweeters are destroyed by low powered SET's and SS amps with high distortion that send upper harmonic information to the tweeter...the tweeders load goes from a fraction of a watt to multi-watt figures pretty fast and then boom.

[grigore]

The speaker ratings are virtually meangless and most revceiver's power ratings are highly exaggerated in order to look good on paper.

You can safely drive any speaker with any amplifier as long as you use common sense and remember the main rule in hi fi, which is: "If it sounds bad, turn it down ...NOW!"

When something starts to sound bad, it's either the speaker or the amp complaining. The amp may be driven well into clipping (not good) or the speaker may be trying to move more air than it's capable of safely doing. In either case, the speaker won't last too long.

I've driven teeney minimus 7's (rated @ 40 watts) with a Marantz 2270 (rated at 70 wpc but actually more like 90 in the midrange) to satisfying, but sane, levels for quite a while without damage.

Of course, if I were to be stoopid enough to try to boost the bass to wall shaking levels and/or try to achieve room filling levels I'd have a problem but, using the above rule, all has been well.

Bravo! I'm happy to see people wich understand the rules of hi-fi and good common sens!