what is clipping

[craig7]

i got some speakers today, a pair of sansui sp z7's and they are soo amazing but apparently if i hook them up to my system

I ended up blowing them by using a low powered, early Pioneer HT receiver, trying to drive them too hard as if I were still using the Bryston. You will blow them again too, if you try to drive them too hard using an underpowered amp into clipping. It's nothing against the speakers. It's just a caution not to drive your amp into clipping.

i dont even know what clipping is. so what is clipping?

 

[craig7]

wold it be safe if i just keep the volume down?

 

[Seth=L]

Clipping is what occurs when an amplifier reaches it's electrical limits. All amplifiers are a sum of their parts. The weakest part determines it's limitation of output. If an amplifier is rated to deliver 5 watts RMS and 10 watts Peak and you take it past that point the amplifier will begin to clip audibly and the sound from your speakers will become distorted. Most commonly clipping sounds like light popping, crackling, static, or garbled noise that accompanies the original source program (music, movie soundtrack). This sound is undesirable for your ears as well as the high frequency drivers of the speaker (tweeters, midrange) most specifically which ever driver operates closest to the upper mid band and lower high band (1000 Hz on up to say 6000 Hz, someone correct me if I'm wrong).

Not only is this a hazard to the sensitive drivers of the speaker, but it is also dangerous for the amplifier. A transistor (an output device) that is driven to its maximum capacity will get hot, hotter than a stable tempurature and could cause it to fail.

I'll use this video of some Foreign folks overclocking a processor (basically a integrated circuit full of transistors) and then proceeding to remove the heatsink.

http://video.google.com/videoplay?docid=5393904704265757054#

Like the processor high output transistors (those used for final amplification) require adequate heatsinking in order to dissapate heat which reduces resistance. If the transistor is not capable enough or the heatsink is too small the amplifier will clip easier.

Other forms of clipping can occur when the power supply is too small or the storage capacitance is inadequate for the task (what is adequate can change depending on the speakers being used).

 

[highfigh]

wold it be safe if i just keep the volume down?

Clipping occurs when an attempt to amplify the signal exceeds the amp circuit and power supply's ability to develop more power. Think of it as running out of power in a car. Literally, it's when the audio signal hits the amplification limit and the signal is clipped off. If you know what a sine wave is, put a straightedge at some point below the maximum and draw a line parallel to the zero line. That's what clipping a sine wave looks like.

The problem with distortion is that when it occurs, harmonics (that could be odd or even multiples) of the original signal are produced and these are usually higher. If it's intermodulation distortion (this happens when two or more frequencies are amplified at the same time), you'll get a sum and difference frequency. As an example, if you amplify 1KHz and 1400Hz, you'll have a 2400Hz signal and a 600 Hz signal. The higher frequencies cause problems because we can't necessarily hear them and if the tweeter can't reproduce them (because they're too high), the energy is converted to heat and heat is what kills speakers.

 

[Seth=L]

wold it be safe if i just keep the volume down?

Any sign of stress should be taken as a sign the amplifier is working too hard and clipping. I wouldn't recommend continued use with the Venturer or any other like powered device after reading highfigh's post here.

 

[craig7]

Any sign of stress should be taken as a sign the amplifier is working too hard and clipping. I wouldn't recommend continued use with the Venturer or any other like powered device after reading highfigh's post here.

so should i keep the volume down and the very second i hear distortion i turn off everything?

 

[JerryLove]

so should i keep the volume down and the very second i hear distortion i turn off everything?

There's not enough information to answer the first part of your question. *if* your system is underpowered than bringing up the volume will cause clipping and, yes, you should avoid clipping.

I'm not familiar with the draw on those speakers. The back on the pic I could find said they were 250W-max 8ohm nominal which is pretty reasonable. They are also 4-way: which from what little I know there is less reasonable.

What's your amp or AVR?

 

[Seth=L]

What's your amp or AVR?

He's powering it with a venturer micro system head unit. He is in desperate need of a receiver.

 

[highfigh]

so should i keep the volume down and the very second i hear distortion i turn off everything?

No, just turn it down. With most sources, like cassette decks, tuners, CD/DVD players, etc, you'll reach the maximum power at about 1:00 on the volume control if it has the rotary kind. If it's remote controllable and uses an electronic volume control, going past -0dB is risky.

You won't hear the distortion unless it reaches double digit whole numbers. .1% is inaudible and most people can't hear 3%. 1% means the distortion is 20dB below the normal signal.

 

[gus_patino]

No, just turn it down. With most sources, like cassette decks, tuners, CD/DVD players, etc, you'll reach the maximum power at about 1:00 on the volume control if it has the rotary kind. If it's remote controllable and uses an electronic volume control, going past -0dB is risky.

You won't hear the distortion unless it reaches double digit whole numbers. .1% is inaudible and most people can't hear 3%. 1% means the distortion is 20dB below the normal signal.

I was trying to figure out what would be the volume control limit on the HK 990. I have the PSB T6 speakers which are rated 20-200 watts. The HK 990 is 300 watts.
Do you recommend the limit to be -0dB, lower or higher?
Thanks