i just noticed that the rms power range for my infinity 10" sub is 50-250watts and the max is 1000watts...it was wired to my kenwood amp at 460watts...is it better to run at the 150watts thats within the power range or at 460watts?
fLyPiNoY7 said:i just noticed that the rms power range for my infinity 10" sub is 50-250watts and the max is 1000watts...it was wired to my kenwood amp at 460watts...is it better to run at the 150watts thats within the power range or at 460watts?
technically...some speakers aren't rated right, but underpowering won't hurt if you don't cause clipping/distortion.jersey_emt said:Yes it is better to overpower than underpower.
the kenwood kac-7201...2 channel but bridged...i was worried that i might be in for a problem if i keep it bridged so for now, the sub is running off of one of the 2 channels at 150w...Rider69 said:which kenwood amp you have anyway?
Rest easy, it no where near 460 watts rmsfLyPiNoY7 said:the kenwood kac-7201...2 channel but bridged...i was worried that i might be in for a problem if i keep it bridged so for now, the sub is running off of one of the 2 channels at 150w...
Whilst I agree, that the true problem is clipping...clipping distorts a signal. So technically...it *is* distortion. But that's one of those a square is just a special rectangle deals...it's all symantics. Basically you're asking too much from the speaker when you clip it. Even if you're underpowering it...because, if the signal is massively clipped, even if it's near what the peak power handling is due to clipping, then you start building up heat and putting excessive forces on the surround of the speaker. So...even underpowering and sending a clipped signal, can pop a speaker.cthomp21 said:Note: This post is directed at no-one. I'm just trying to help debunk one of the biggest car audio myths out there (besides my HU puts out 60x4).
"Underpowering" will never, ever, ever, ever, ever damage a speaker. Do your speakers suddenly blow when you turn down the volume? Of course not. Also, a speaker will just as happily play 100% distortion as a signal with 0% distortion.
There are two things which can kill a speaker:
(1) Exceeding the speaker's mechanical limits. For example, if you put a 20Hz signal into a tweeter you can pop it without much power at all (much less than its rms power rating). For subs, the enclosure type as a great deal to do with its mechanical limits. Given the same sub, smaller sealed boxes will be less prone to over-exursion than ported or infinite baffle setups.
(2) Exceeding the speaker's thermal limits. This is where you put too much power into a speaker and melt the voice coil or damage something else.
The real mystery that most people don't understand is clipping. When you clip an amp (set the gain too high and ask the amp to give all its got), it can actually produce twice its rms power.
For example, I've got an amp rated to produce 100w, and I've got a sub rated to handle 150w. Let's say I turn the gain up to its maximum, turn on the bass boost on the amp, up the bass level on the input signal, and turn the volume up to its maximum. Now, the amp is running a clipped signal and is producing 200w worth of power.
Inevitably, the sub blows either through overexcursion (mechanical limits) or melting (thermal limits) or even a combination of the two. Most people blame it on distortion or "underpowering" not really understanding that their sub blew because it was being overpowered by the amp (200w being sent to a 150w sub).
If you had a sub that was rated to handle 200w, it would play the signal with no problems (provided you aren't maxing its mechanical limits). In most cases, it would sound like absolute crap, tho.
In this particular case of the Infinity sub and KW amp, it depends what voice coil config you've got.
If it's a 4ohm single voice coil (which is what I'm assuming), run it in bridged and turn the gains down. The amp is rated to produce 460w rms while the sub is rated to handle 250w rms. As for what each can "actually" do is a good question.
-Colin
First off, let's define CLIPPING distortion...
This is when an amplifier has reached its maximum output capacity yet tries to keep up with the input signal gain ratio between the signal source "HU" and Amp. The amp hits an imaginary wall whereby the output signal is no longer a symetrical replication of the input signal. The wave form in, does not match the wave form out in shape or amplitude. (you can see this easily if you had a A/B channel oscilloscope; channel A connected to the amp input, channel B to amp output) The only difference you should see between channel A & B are signal amplitude values. If the signal shape varies considerably in channel B, you have a problem with clipping.
So.. what's wrong with this picture? The amp tries to put out the appropriate power, but runs out of voltage from the supply rails and we get a flat spot at the upper and lower peaks of the wave form. In an extreme case, "severe clipping", there is so much additional energy buildup (heat) into the voice coil(s), but the cone does not move (motivate) enough to cool the voice coil and former adequately. Hense, the voice coil over heats and either seizes in the gap or burns the voice coil windings. RESULT: OPEN CIRCUIT and a blown speaker!
OK, what happens to the speakers when they are underpowered? Under normal listening conditions... NOTHING! There is adequate signal voltage from the amplifier to motivate the speaker. This moves the speaker cone and draws/expells air to cool the voice coil adequately. No problems here... just modest output from the speaker. This happens all the time when we ride with the tunes playing low enough to hear our buddy in the co-pilot seat chattering on his/her cell phone.
SO WE CAN USE LOW POWER SAFELY ON SPEAKERS?
Yes... When we use a small amp to drive a high powered speaker, the speaker can take all the "clean power" the amp can deliver and more. But it's when we push the amplifer into high distortion ("clipping") mode, the speaker cannot move (motivate) in and out adequately to cool the voice coil. Eventually, this will even fry a very expensive speaker in this manner.
WELL THEN WISE GUY... WHAT CAUSES THIS "CLIPPING" THING?
Glad you asked! The amp will try to meet the power demand placed upon it, but it cannot exceed its design capabilities. This in turn, produces the deadly "square wave" output to the speaker. The speaker sees this severely clipped signal as something similar to DC current. Speakers cannot deal well with DC inputs. The cone goes in or out and stays there. No motivation to cool the voilce coil and sooner or later, the speaker will fail.
servoeyes said:Ok...I'd quote that but this would all get muddled.
I guess what I'm trying to say is that overpowering is good with a clean undistorted signal. All too often, when you use an *underpowered* amp not matched to the speaker well, and push it to clipping to attempt to get the sound you want from it (thus overpowering the speaker) is when you blow the speaker.
Like I said...it's all symantics...we're getting to the same point, but describing it differently (causing confusion).
So...conclusion:
underpowering = ok...conditionally.*
overpowering w/ clean signal = ok
overpowering through clipping = bad
* = if you have a motor structure that wants power (BA pros) and don't give them enough power, then they still won't sound great.
We agreed on zeez points?![]()