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power ratings

361 Views 8 Replies 6 Participants Last post by  jcrobso
What happens if you pair speakers ( 50 to 85 watts ) with an amp of 100 watts? Could the speakers be damaged? I asked this question in the speaker forum, but it may be more appropriate here.
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It's possible but usually your ears will stop you before you do any damage. Besides, such ratings are rarely very reliable.

About 20 years ago JBL did research and found out that most speakers are damaged by over driving the amp into clipping. When an amp clips the effective power of the clipped waveform can be 2 or 3 times the rated power of the amp. John
Whats also interesting is that on my 3.6R/SE Maggies the bass foil gives out earlier with the Pathos AMP than with the big Krell. the more stable power the AMP can deliver the more control it has over a speaker and can be pushed louder. At least thats what i have experienced. The pathos cannot drive below 4 ohm loads and delivers 95wpc at that rating. The Krell can drive below 1ohm loads and delivers 440wpc into 4 ohms. Some speakers react more than others id say. But its usually the cllipping of the AMP. I would buy a AMP that is more powerfull so that you can make sure that it does not clip. Your ears will hear when the speaker is stressed.
interesting what about the other way - i have an 85w per channel receiver denon 1905 and front speakers rated at 300w? can this be a problem?
Only if you overdrive the amp so that it clips - this squews the power/frequency distibution into the tweeter region and may damage the tweeters.
how will i know and what volume level should i be running it at?
What is the sensitivity of your speakers, how far away from them is the listening position and what are your target reference and peak SPLs at that position?

Given this, it is possible to estimate if your speakers are capable of delivering this, and how much power is needed to do it with some (fairly) basic math.
Sensitivity of speakers is with 1 watt of power , at 1 meter in a anechoic room what is the db level that a speaker will produce. Most home speakers seem to be in the 86~90 db range. So if a speaker sensitivity of 90db at 1 watt it will take 10watts to get it to 100db and 100 watts to get to 110db at 1 meter.

Now if you are 2 meters away the db level will drop by 6db. John
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