Speaker sound at clipping?

[Harrison476]

Could someone please describe the speaker's sound when "Amplifier Clipping" happens? My interest is when clipping occurs at moderate volume settings. Volumes somewhere around 75- 80 db sound levels.

Thanks

 

[markw]

Could be any of several indications.

Could someone please describe the speaker's sound when "Amplifier Clipping" happens? My interest is when clipping occurs at moderate volume settings. Volumes somewhere around 75- 80 db sound levels.

Thanks

Harshness is one indication, but this could also be an indication of an amplifier clipping as well.

A loud "POP" can occur when the speaker has reached the extent of it's travel, but this is generally a symptom in larger speakers.

Tweeters, OTOH may simply quietly die without too much warning.

Since you say it occurs at such a low level, would tend to suspect the amp more so than the speakers.

But, if ANYTHING sounds "not right", it's a sound of a problem somewhere in the signal chain and you should turn it down immediately.

 

[fredk]

I think the effects can be quite subtle if there is not a lot of clipping (ie: if it is clipping only on transient peaks for instance) and it can get very nasty if there is substantial clipping.

I have never noticed clipping on my system though so I can only repeat what I have read.

 

[Swerd]

Clipping at low levels, say less than 10%, can be hard to identify by ear. When you can hear audible noise, you already have a lot of clipping. Depending on your speakers, it may be damage-inducing clipping.

I once saw a good demonstration of how clipping occurs more often than I or most others realize. It involved speakers of reasonable sensitivity, about 87 db if I recall, playing a standard pop song at levels that were a bit louder than conversation in a busy room (not a quiet room like a library) and two different amps. One amp was about 100 wpc and the other was 250 wpc, a "big iron" amp. The guy demonstrating this had two volt-ohm meters rigged up so that one showed voltage averaged over a 12 second period, and the other showed the highest voltage over the same 12 second period.

Most of the music was easily within range for the highest output voltage from the 100 wpc amp, except whenever the drummer hit the snare drums with a single shot. At that point the amp clipped. This was easier to see when they switched to the big amp. With the same snare drum shots, the voltage was within range for the big amp, but beyond the ability of the small amp.

Interestingly, no one could hear a difference, but the smaller amp clearly had begun to clip. Maybe all amps should have clip indicator lights.

 

[Harrison476]

Guys:

I had recently changed the speaker setting back to 4 ohm. I originally set the setting for 8 ohm. I did this to reduce heat. I also re-scanned speaker set-up, accepted all values. What I heard was slight popping and distortion in the ”string” instruments, a "blurring of notes" . Source was cd of Diana Krall, tune was "Peel me a grape".

Thanks to all

Swerd:I replied to yours and others comments on another thread and I lost the dang thing before I submitted it.

 

[CallMeJoe]

My best description of clipped audio is "fuzzy". The extreme example is the electric guitarist's "fuzz pedal". That type of distortion is produced by intentionally driving a buffer amp into a high level of clipping.

 

[Harrison476]

My best description of clipped audio is "fuzzy". The extreme example is the electric guitarist's "fuzz pedal". That type of distortion is produced by intentionally driving a buffer amp into a high level of clipping.

yep thats it !

Now, what should I do ?

 

[highfigh]

Could someone please describe the speaker's sound when "Amplifier Clipping" happens? My interest is when clipping occurs at moderate volume settings. Volumes somewhere around 75- 80 db sound levels.

Thanks

If you have clipping at 75-80dB, your equipment has problems or you're overdriving the input. There's absolutely no way you should have audible distortion at that level, especially considering the fact that many speakers put out close to 90dB at 1 Watt, measured from one meter. At 80dB, you would be pushing about 1 Watt and your listening position would be about 10'-12', depending on the acoustical properties of the room.

In light of the comments about the comparison with the 100W and 250W amps and the measured voltages, if anyone still uses a cassette deck, connect it and watch the VU meters, especially if they are LED, florescent or some other non-ballistic type. Play a CD or DVD and watch for peaks of greater than 20dB- they used to be very common but I don't know if they still are because I haven't had a cassette deck in my system in years but when I worked at a stereo store, we used this to demonstrate the need for more power. If necessary, play an older CD. Then, check the "average" power output from the amp while it's playing. If your amp is 100W/ch and you figure that it's putting out about 1W on average, it's pretty safe to say that any peak of more than 21dB will be distorted. If it's 23dB or more, it's not going to be undistorted (I doubt most receivers can reproduce clean peaks of double the rated output power) and if the peaks are in the 30dB range, there's not much chance that they're undistorted at all because at that point, it's trying to reproduce 1000W peaks.

THAT'S why we all need powerful amps, not so we can constantly play it at high SPL. The word 'effortless' has been used for a long time when describing audio equipment and high power amps are associated with effortless sound very often. When an amp is right at the limit of its performance, it's not going to sound as good as we want.

 

[highfigh]

yep thats it !

Now, what should I do ?

Start isolating each piece of equipment to find out where the distortion is. Play the speakers on different equipment- if you hear it, you know they're the cause. If not, use different speakers with the rest of the system. If it's there, use a different source.

I wouldn't necessarily discount the possibility that the distortion is present on the recording. Play other music and listen closely for what you were hearing- careful listening will reveal all kinds of sounds you never heard before, from chair squeaks, sheet music rustling, hum and noise from amps and pitch shifts from someone causing the analog tape to slow, like at the end of "The Great Gig In The Sky" on Dark Side of The Moon.

 

[walter duque]

What amplifier are you using? To me it sounds like HIGHFIGH says your overdriving your input. Your input is where the distortion might be coming from. I mean that's one possibility.

 

[markw]

By any chance, you're not plugging the CD player into a "phono" input, are you?

 

[Harrison476]

It was in the Audyssey set-up that I ran after I changed the speaker setting to 4ohms. Why I do not know. When I changed the crossover frequency for the front channels it sounded great with no fuzzy popping sound. I put the same recording on, same source, changed the crossover to where I had them@ 80 Hz and sounded prefect.

Thanks for all the help!


Oh I left the equalizer settings the same as chosen by Audyssey. In the equalizer set-up I can not see what values the Audyssey chose? I don’t understand that. In the manual set-up election, you can see of course any adjustments values.

 

[fredk]

after I changed the speaker setting to 4ohms.

That explains it. The 4 Ohm setting reduces the power your amp can deliver. Either of the amps you list in your profile in the link should be able to drive a 4 Ohm load just fine without engaging the 4 Ohm setting.