Clipping - Is it harmful?

[UncleN00b]

Is the distortion in a production caused by compression and clipping dangerous to audio equipment at high volumes?

[jNive]

yes - the hard-limiting and excessive clipping produced results in square waves being sent ot the speakers.

A pure square wave consists of a low-frequency fundamental frequency, and an infinite number of all the odd harmonics. For a speaker coil, repeated square-waves can cause excessive current in the coil etc etc etc - it can certainly have an affect

[UncleN00b]

yes - the hard-limiting and excessive clipping produced results in square waves being sent ot the speakers.

A pure square wave consists of a low-frequency fundamental frequency, and an infinite number of all the odd harmonics. For a speaker coil, repeated square-waves can cause excessive current in the coil etc etc etc - it can certainly have an affect

Another great reason why I will avoid such productions. I think this would be another good argument for our cause. Are there any sources on the net that go in-depth on this? It would be nice to have extensive details with pictures enstuff.

[jNive]

there was one posted around the place, if i find it, i'll attach it here

[Snoepie]

yes - the hard-limiting and excessive clipping produced results in square waves being sent ot the speakers.

A pure square wave consists of a low-frequency fundamental frequency, and an infinite number of all the odd harmonics. For a speaker coil, repeated square-waves can cause excessive current in the coil etc etc etc - it can certainly have an affect

Another great reason why I will avoid such productions. I think this would be another good argument for our cause. Are there any sources on the net that go in-depth on this? It would be nice to have extensive details with pictures enstuff.

I agree. I was pretty shocked that people completely ignore the fact that this actually is bad for your body on the long run let alone equipment. I think we should emphasize these 2 arguments more.

[SiriuslyCold]

This is a rather technical discourse on amplifier clipping

http://sound.westhost.com/clipping.htm

as opposed to digital clipping caused by compression. As Ian mentions in one of the posts on metbb, clipping embedded in the signal isn't necessarily damaging to the speakers if you do not push the volume up; i.e the amplifier just sends the click sound to the speakers. Of course playing this at full volume may damage the speakers. Playing anything that has loud peaks may damage speakers.

But that will be due to amplifier clipping, which is an entirely different animal - there's a similar type of clipped signal, but this happens when the amplifier just doesn't have any more power to reproduce the signal peak, and cuts off abruptly. Result? fried speakers.

The short story is, damaged equipment as a result of clipped CDs is not a strong case against over-compressed music. (see Ian's follow up)

[jNive]

correct - unless you blast the volume for extended periods - or have slightly damaged/dodgy speakers to begin with - however at the same time. The rapid oscillation of high RMS value at high volume can certainly induce a high current in the speaker coil - this induces a higher output of heat - just like a transformer.

[UncleN00b]

So, if you play a very clipped and overcompressed album at a similarly loud sound/intensity (not going by the numbers on a volume dial, but matching the volume intensity with your ears) of an album that does not have clipping and isn't overcompressed, the clipped album will have a higher chance of damaging audio equipment than the latter album?

(Sorry, my sentence structure is especially jacked up this morning.)

[SiriuslyCold]

So, if you play a very clipped and overcompressed album at a similarly loud sound/intensity (not going by the numbers on a volume dial, but matching the volume intensity with your ears) of an album that does not have clipping and isn't overcompressed, the clipped album will have a higher chance of damaging audio equipment than the latter album?

(Sorry, my sentence structure is especially jacked up this morning.)

lets look at it this way - the amp doesn't know a clipped signal from a permanent high frequency screech or high freq white noise. As long as they are played within the amp's capabilities neither are going to cause it to run out of steam. Perhaps in a roundabout way it's safer - the clipped signals are already very loud, and prevents you from playing at a volume that will cause the amp to clip when there is a peak. Also overly compressed albums don't have peaks so while the distortion sounds like its hurting the speakers, you turn down the volume and are rarely in danger of overdriving the amplifier.

now, matching volume intensity - this is measured in decibels, and usually called sound pressure level (SPL) - anything above 105db is hard to listen to for long periods of time, so you probably listen at 75db or 80db SPL

(you can get an SPL meter from Radioshack to test this, if you're curious. Home theater fans probably already have one they use to set up the system)

The relationship between amplifier power and volume (SPL) is dependent on the speakers - called the sensitivity and is measured at the SPL they can produce given 1 watt of power measured at 1m. This is usually written db/w/m, and averages between 87 - 90.

Say for example your speakers are rated 90dB 1W/ 1m sensitivity (fairly sensitive)

i.e. given 1W of amplifier output, your speakers will produce 90dB when measured 1m from the speakers

Code: Select all

1W      90dB
2W      93dB
4W      96dB
8W      99dB
16W      102dB
32W      105dB
64W      108dB
128W   111dB
256W   114dB
512W   117dB


you aren't sitting 1m away from the speakers - so this table needs to be adjusted as follows

Code: Select all

Power   1m      2m      4m
1 W      89      83      77
2 W      92      86      80
4 W      95      89      83
8 W      98      92      86
16 W      101      95      89
32 W      104      98      92
64 W      107      101      95
128 W   110      104      98
256 W   113      107      101
512 W   116      110      104
1024 W   119      113      107


So, what does 100dB mean to us?

Code: Select all

Whisper   20dB
Normal Conversation   60dB
Busy Street Traffic   70dB
Vacuum Cleaner   80dB
Large Orchestra   98dB
Walkman at Maximum Level   100dB
Front Rows of Rock Concert   110dB
Threshold of Pain   130dB
Military Jet Takeoff   140dB
Instant Perforation of Eardrum   160dB


So you can see that any reasonable amplifier has no problems producing any sound up to 100db SPL. You only need 15 to 20 watts amplifier.

If your amplifier is rated 40W and you are trying to push the SPL to 110db sitting 2m away, then it will clip. So, lets take a piece of music with dips and peaks - the average level is reasonable and you are listening at 80db, sitting 2m away. The amp is just using 1W. When the music peaks at 110db the amp now tries to reproduce that SPL, it can't and runs out of steam 40W, and clips. This is what fries speakers. Of course most modern hi-fi equipment has circuitry that either shuts down the amp or some other fail-safe routine so it doesn't happen

With DM and other overly compressed albums, you cannot listen for long periods at higher than 80db anyway, and there are no peaks in the music so it's - dare I say - relatively safer for the amplifier and your speakers.

[UncleN00b]

Thanks, now I get it. Good post!