What is clipping?

[lakegville]

I hear this term used quite often and i know it is not good. I have experienced some receivers go into "protect" mode as volume is turned up.....is this clipping? I have also had a few speakers make an awful sound much like a turntable needle being dragged across a record when too much volume is administered. This would not be a forming of clipping would it? I guess what i am asking for is kind of a "clipping for dummies" brief summery....what exactly is it? what causes it? how to keep it from occurring? (since i have read where it can be destructive). Maybe it is something that only happens with power amps? Thanks in advance.

 

[Northwinds]

Clipping is when you amp runs out of horsepower and starts distorting

 

[sKiZo]

Clipping is a form of waveform distortion that occurs when an amplifier is overdriven and attempts to deliver an output voltage or current beyond its maximum capability. It's called that because the peaks of the waveform are clipped off, resulting in distortion.

Hard clipping is more of a solid state thing resulting in harsh crunchy noises. Soft clipping is more prevalent in tube equipment where it's more of a fuzz effect.

 

[sqlsavior]

The "needle dragging across the record" sound may be the speakers reaching their mechanical limitations. Protect-mode may or may not involve or result from clipping.

The sound I associate with clipping is an addition of harsh distortion, but not necessarily large amounts of it. With a low-power amp, and relatively inefficient but robust speakers, it is possible to detect the threshold as you turn the volume knob from loud, to party-loud - at a certain point an unpleasant crunchiness is added to louder portions of the music.

The examples you cite are pretty extreme, undesirable, and probably way, way past the clipping threshold.

 

[lini]

lgv: An analogy would for example be the size limit of the object to still fit on the pic with a camera lens with a given focal length at a certain distance from the object... If you're too close (= input signal level too high) or can't sufficiently reduce the focal length (= gain too high), parts of the object will be clipped on the pic.

Greetings from Munich!

Manfred / lini

 

[bhunter]

Here's a paper on clipping and its effects that Ken Kantor referenced a few years back:

www.adx.co.nz/techinfo/audio/note128.pdf

 

[lakegville]

unpleasant crunchiness is added to louder portions of the music.

yes i would say that is a very accurate way to describe it...I only hear this unpleasant noise in the loudest parts i have heard it now from several different pairs of speakers being driven by multiple amps when arriving at "party loud" territory. I guess this is a sign of clipping. Are higher watt amps less susceptible to causing this? I have a db meter and i have been chasing 100 db sustained with some of my systems. Some of my speakers seem more prone to this than others.

 

[Djcoolray]

Man...

If your hearing all that, your system is not up to the demand of your needs. You need some speakers that can handle the punishment and a receiver that can drive them. Time to graduate up to the big boys that are better toys.

 

[Djcoolray]

Speaker wattage should be double that of the amp or receiver.....

I read that in stereo magazines when I was a kid.

 

[sqlsavior]

yes i would say that is a very accurate way to describe it...I only hear this unpleasant noise in the loudest parts i have heard it now from several different pairs of speakers being driven by multiple amps when arriving at "party loud" territory. I guess this is a sign of clipping.

Yes, that unpleasantness that you can add or subtract with the volume control is most likely clipping (there could be transducer explanations as well), but it can be present even earlier, in that transient peaks, like a "rim shot", can be clipped less noticeably.

Are higher watt amps less susceptible to causing this? I have a db meter and i have been chasing 100 db sustained with some of my systems. Some of my speakers seem more prone to this than others.

Yes, higher-watt amps are less susceptible to clipping in an absolute sense, but in practical terms, noticeably louder (3dB) requires twice the power, which quickly became impractical, although that is less true today. The key was speaker efficiency, and still is. Sustained 100 dB would have peaks 10-20 dB higher on dynamic program material. The traditional approach is horns, and the Klipschorn is the most efficient at 105 dB/w, due to its bass horn. It would get you to 120 dB peaks, cleanly, with a 32-watt amp. At that point the cupboards and windows dominate the noise and distortion, anyway.

 

[WaynerN]

All amplifiers have power supplies that feed the output devices. These power supplies have a limitation to them. When the volume control is advanced to such an extreme point, the ability to "drive" the output devices becomes inadequate. The result has the musical sign wave being "chopped" at the top of the wave form, resulting in DC voltage, which is unpleasant to hear, and is the major cause of speaker destruction.

Its kind of like running a 20 amp device on a 15 amp circuit, only in this case, the circuit breaker trips.

'ner

 

[Gibsonian]

Speaker wattage should be double that of the amp or receiver.....

I read that in stereo magazines when I was a kid.

It's exactly the opposite in my opinion. Should read amplifier power should be double that of the speaker rating.

McIntosh and other manufacturers usually recommend more power than speaker can continuously handle to avoid sending a clipped signal to the speaker. Is easy to hear clipped music with an amplifier supplying only half of what the speaker can handle.

Compressed original recordings and clipping caused by underpowering are both types of distortion that I am sensitive to and dislike.

 

[sKiZo]

Are higher watt amps less susceptible to causing this? I have a db meter and i have been chasing 100 db sustained with some of my systems.

Depends on the equipment and it's condition. I push 100db+ a lot (Damn you, Porcupine Tree!) and my 200wpc McIntosh MC2205 would crunch out regularly. Granted, it had "issues". That said, my 70wpc tube amp will barely fuzz (soft clip) every now and then, same levels, same speakers, same material.

~~~~~~~~~~

Oh. Clipping is also high on my list of annoying office sounds ...

 

[johnr66]

It is interesting the way electrical or mechanical or even digital limits to the signal is clipped. For example, with digital, it simply runs out of digits to represent the signal any larger. On vinyl, it can manifest itself in the sound in several different ways depending on the frequency. In either case it can and should be avoided before the recording makes it to the end user.

Occasional light clipping should be inaudible as the flattened top of the waveform is slight and nearly tangent to the peak of the waveform anyway, thus the harmonics will be small. If you are hearing a lot of distortion at higher volume you are clipping pretty severely and can even cause damage.

With some amplifiers/receivers at high volume there can be a very audible popping and cracking sound. This is the result of its current limiting circuit functioning with a reactive load. It sounds far worse than any clipping and can be heard clearly above the music. A similar sound is produced when the speakers voice coil smacks the back of the magnet structure when played at too high of level.

 

[JoeESP9]

Speaker wattage should be double that of the amp or receiver.....

I read that in stereo magazines when I was a kid.

Speaker wattage ratings are mostly useless and worthless. Anyone who has been around audio gear for a while knows this. I read (had subscriptions) to all those magazines (Stereo Review, Audio, High Fidelity) that used to be published. I don't remember seeing anything saying that speaker wattage should be double that of the amp or receiver published anywhere.

 

[Djcoolray]

Speaker wattage ratings are mostly useless and worthless. Anyone who has been around audio gear for a while knows this. I read (had subscriptions) all those magazines (Stereo Review, Audio, High Fidelity) that used to be published. I don't remember seeing anything saying that speaker wattage should be double that of the amp or receiver published anywhere.

I'm talking like mid sixties and the magazine article was emphasizing clarity.

 

[woodj]

As Joe said, speaker wattage ratings are mostly useless.

 

[Djcoolray]

Maximum amplification for me

It's exactly the opposite in my opinion. Should read amplifier power should be double that of the speaker rating.

McIntosh and other manufacturers usually recommend more power than speaker can continuously handle to avoid sending a clipped signal to the speaker. Is easy to hear clipped music with an amplifier supplying only half of what the speaker can handle.

Compressed original recordings and clipping caused by underpowering are both types of distortion that I am sensitive to and dislike.

Really ?

Maximum signal amplification for me is 168 watts and maximum watt imput for my speakers is 400 watts and I enjoy crystal clear sound at any volume level without clipping or increased volume distortion. Fact is, before reading the forums on Audiokarma I didn't even know what clipping was. I figured someone was playing with under powered equipment and I think that is the case. I've been pounding those speakers into the ground since '93 when I bought my speakers and receiver new and haven't had a complaint from either one of them. Just had the receiver cleaned and put on the bench and everything checked out perfect.

 

[Djcoolray]

So, what you guys are saying does not make sense...

 

[woodj]

You need to look at the complete picture and not be selectively looking at the individual "bits and pieces".