Clipping? What does that mean exactly?

[TIbor]

I was reading about some bose cubes, because my friends always bragging about them. I tried to kindly say they sucked but really could get my point out right. Any way it was talking about clipping in some scenes in a dvd from the bose, what does that mean exactly. And secondly, I have all my speaks set to small, and I think main+sub for bass at 80hz crossover. When running the dve disc, there is a test called the buzz and rattle which brings a tone from high down to 20hz. My rf3II where still audible in the 70 range, does this mean I should change my mains to large of is the main+sub option essentially the same

Thanks

[damonrpayne]

I believe clipping refers to overdriving an audio component, typically an amp or speakers, to the point where the device distorts, ie it is overloaded.

[easylistener]

As for setting your mains to large or small it is a personal thing. Try differnt settings and see what you like the best. I have mine set to large and the crossover set at 60hz. This is what sounds best to me and my room.

[ygmn]

Clipping is tern dealing with output from amplifiers...

Clipping is when the amplifier cannot deliver any more power when the source material says it wants more power...so the amp...just gives all it has....

so if you were to look at the output of the amp...it would look like a sine wave....but when clipped the tops of this sine wave would be flat...at this output limit....Also there would be severe distortion as you reached the limits of the amp

Clipping is not good for speakers, amplifiers, sound or my ears...hehehe

[Griffinator]

Actually, clipping is a very generic term that simple refers to output of any device in a given chain exceeding 0dBfs.

[j-malotky]

Have you ever heard Jimi play guitar? Having your amp overdriving your drivers is the classic clipping sound we have all heard in music. The clasic distortion sound.

Overdriving or square waving your guitar amp, or sterio amp to clipping is almost the same thing. The reason it works for guitar, is the speakers have a HUGE magnet that can handle the extra power. Your Klipsch speakers can not, they will blow the diagphram with very little clipping.

JM

[DrWho]

for the more visually inclined, i drew up a picture to help demonstrate what happens...

the red lines represent the maximum output capable by the device. the device really can be anything in the signal chain that recieves an input and puts out a larger output. The most obvious is an amplifier (so we'll use that as the analogy).

the black lines represent what the input signal "is supposed to output" and the grey shaded areas represent the actual output based on the maximum output capable by the device. the blue lines, represent where clipping is occuring.

in a waveform, the distance from the middle to the crest (or trough) is the amplitude. related back to sound, the amplitude would represent the volume of the signal. as long as the amplitude stays within the means of the device (aka, the black lines are inside the red lines on the diagram), then the signal is clean...aka, no clipping (a form of distortion) is happening.

if however, the amplitude exceeds the capability of the device (black lines outside of the red lines on the diagram), then the output starts to get clipped. when clipping occurs, the amplitude of the waveform (the height of the waveform) maxes out and it can't get any louder, but at the same time the input is telling the device to go louder. what ends up happening is the top of the waveform gets cut off and becomes a straight line at the max output of the device until the waveform comes back down into the workable range of the device. This straight line is essentially DC (direct current) which is very effective at burning out drivers.

ok, so i explained the whole process referring to the "device" and i mentioned earlier that an amplifier is the most obvious device that comes to mind. however, a speaker too can also be considered a device...when a speaker is no longer capable of playing the amplitude of the signal being pumped into it, then the same thing happens where the amplitude gets cut off. clipping can happen in the reciever, in the cd player, anything in the signal chain. i've even heard clipping coming through the cable box when watching tv!

[ygmn]

good explanation DRwho...and nice pics.....

I think I was trying to say the same thing...but with less words hehehehe

thanks for confirming what I think of as clipping

[Colin]

Aahh, clipping, yes the graphic is excellent, yes clipping certainly occurs when the volumes are high, but it may also occur frequently within the passages of music at normal volumes unless you have super-sensitive big ole horns. Just visualize those unclipped peaks on the graph several times higher. Heres why:

The rating of an amplifier is at the low point of its THD curve. The amplifier is usually capable of twice that power, although at much higher levels of THD. At its maximum output, the THD of amplifiers screams skyward like a rocket taking off. With tubes as unique stores of energy, a tube amplifier puts out a lot more current than its rating implies. Tube amplifiers may average 5 times the current of its simple RMS rating.

Nonetheless, I hope I remember this right: Lets say you have a 25-watt amplifier idling along with a typically 85dB sensitive loudspeaker, which means that it takes about three watts to generate a moderately loud average music volume (85dB) at the listening spot in a typical room.

Every additional three dB louder requires something like a doubling of the amplifier power. To reach a 88dB peak, the amplifier needs to put out 6-watts. Now the typical CD has fast music peaks some 15-16 dB higher than the average music level. So a CD averaging 85dB in music level can have fast peaks at 100dB.

To reach those fast peaks properly, without clipping, the amplifier with this loudspeaker needs a quick 38-watt burst of energy. You may NOT hear it, but the amplifier limited to just 25-watts is actually clipping, during those micro-second passages, at about 95db, or only 10dB higher than the average music level. As the amplifier reproduces those fast musical peaks, it is putting out maximum power at very high levels of distortion.

Doubling the power of the amplifier doesnt make an enormous difference in the volume that it can produce with 85dB sensitive loudspeakers. That only makes the sound some 10dB louder, but it does prevent clipping during fast musical passages, so the more powerful amplifier should sound better with these speakers.

The type of distortion makes a very big difference. In a tube amplifier, some say the type of distortion resembles natural orders of musical instruments, so the heavy distortion when the amplifier is clipping during musical peaks is said to be good. Plus, the weaker horsepower of the tube amplifier rolls off quickly during those peaks, this is called soft clipping.

The heavy distortion of a SOLID-STATE amplifier when it is clipping does NOT roll-off gently, this is called harsh. When your ears are ringing because the music is so loud, it is NOT merely the volume that is making the cochlea cilia of your inner ear vibrate in pain, it is also the tremendous amount of distortion as the amplifier clips continuously.

With super-sensitive 90dB loudspeakers, the 25-watt amplifier again clips fast musical peaks at 25-watts, but this time it is near the musical peak, about 100dB. At the 85dB playing level, this amplifier and loudspeaker combination should NOT obviously sound like it is clipping fast musical passages.

With an ultra-sensitive 95dB loudspeaker, the little 25-watt amplifier has plenty of power to reproduce the 100dB musical peaks with room to spare. Call this headroom.

With fantastically sensitive 100dB/w/m big ole horns, things begin to get a little ridiculous compared to the typical solid-state receiver and cone loudspeaker set-up. For one thing, a flea-powered 3-watt tube amplifier will reproduce the 15-16dB highs of the CD at 100dB, while the 25-watt amplifier could produce an ear-splitting 110dB before clipping.

If it wasnt for the low impedances of the woofers, a good low-powered solid-state or tube amplifier is all the power anyone needs with fantastically sensitive big ole horns.