DaveGrun

What does it mean when your speakers clip? and what causes it?

Sin

Sound is pressure waves in the air. These waves can be represented, in a linear form in the form of sin waves. These waves, are actually VERY complicated normally, but nonetheless, all can be represented by an infinite number of sin waves.

Sin waves are generally smoothe, with peaks and valleys. However, when a high powered amp is pushed too hard, distortion occurs.

The sin wave represents the voice coil or pressure wave, with rest at 0, peaks and valleys are linear push and pull of the voice coil through excursion, or high and low pressure regions in a sound wave.

Shen an amp is pushed too hard, the voice coil is no longer moving at the same rate the power is being delivered. Essentially, instead of rising to a smooth rounded peak or valley, the curve looks like it was simply chopped off. Thus energy is being applied to move the woofer to the peaks and valleys, but the speaker isn't making it to those peaks and valleys. Thus there is a disproportional amount of movement to energy input. And this movement is VITAL for cooling. If you don't already know a lot of the energy that you input into any audio system ends up as heat, as opposed to actual kinetic energy in the form of sound waves. Thus the proportion of energy input and heat production is no longer in balance. This then causes the voice coil to overheat.

With very bad clipping, not only are the peaks and valleys chopped off, the sin waves, or if you will, the pressure waves in the air, are no longer smooth, instead, they have right angles, or SHARP edges between high and pressure waves, which is VERY stressful to a speaker. Imagine moving your arm up one foot, then back down to rest, then down then back to rest, every 10 seconds. Pretty easy right? Now instead of a smooth transition from rest to high position, back to rest, down to low position, back to rest, smoothly, try doing this spending nearly no time whatsoever moving from high to low. When this occurs, the speaker is actually being driven, with up to double the the power the amplifier can provide without distortion.

Basically, clipping is a term which refers to pressure waves, as represented by sin waves, and how the peaks and valleys are not reached by the speaker, because the amp is unable to drive the speaker to those levels, while the speaker is receiving energy that is causing heat. This occurs when an amp is being pushed beyond its ability to push cleanly.

Clipping can actually be heard by a trained ear, WAY before damage is really being done. But many cannot hear it, and keep blasting their systems beyond the means of the amp. And when doing so, they go through subs all the time.

So just because the volume **** goes up to say 50, doesn't mean you can play your system at 50 without damaging things. There are lots of factors which determine the maximum volume level. Things like the amplitude of the original signal, the gain settings, various tone contouring settings, the actual sound information being played, etc, etc.

It's hard to describe what clipping sounds like, because the sound of a sound clipping varies depending on the intended sound wave. In general, it usually appears as distortion. But there are times when it sounds like harmonics.

blizz20oma

iTrader: (1)

That's a great thorough explanation. I think the only thing I'd have to contribute or add to that dialogue was that I thought they were 'sine' waves

From past experience I think some subs take clipping better than others. I had limitations in my older car that I've come to attribute to either bad factory ground(s) on engine components, or more likely just the weak stock alternator (I never found out if it was a 60A alt or an 80A alt, but even 80A isn't much), and in trying to run a class A/B amp putting out 500w rms, I don't think the amp could ever get nearly enough juice to keep control of the sub...so on low draws, I would experience audiable clipping. The first sub I tried was a Diamond M5 10", aluminum cone, which on one of these occassions, split right through the cone. I got it replaced with my current Treo. The shop verified my amp settings and let me go even with it clipping audiably, and to my surprise, the sub held up for about 8-9 months before going out. They replaced it under warranty and at that time I was selling the car, so I have the new one now. For the week that my system was in operation in the Max, I didn't experience any audiable clipping - everything sounded clean from the sub. (However, due to loose wiring at a fuseholder - I didn't have the right wrench and rushed the job - I blew a fuse and am waiting for my JL amp to get here to re-install).

If a sub like that put up with clipping that you could definitely hear (sounded like the vc's were actually smacking something hard, a 'plinking' type noise), then I'd imagine some would put up with very minor, pretty-much-inaudiable clipping for quite a while. Some more
than others, obviously.


What do you guys suggest to minimalize/reduce clipping? Verify your wiring is as neat/tight as possible, verify wiring is correct for the speaker/amp in terms of maximum draw, etc, verify amp is correct in terms of power output for speaker, verify that amp is getting enough voltage needed to provide the level of power that the speaker needs with minimal distortion? Anything else? S/N ratio/distortion of the amp?

I figure you can use a multimeter to test the voltage at the amp connection, but how do you figure out how the amp responds in terms of power output at various levels of voltage (I know some amps handle slight drops in voltage better than others).

Sin

It is definetly sine, but after using computational calculators all day long, sin ends up being sine in my head, cos, ends up being cosine, etc.