So what does clipping sound like?

Whaleman

Hi-Fi Rescue Mission
No one is home, so I am playing music at a good clip, say 10-11 o'clock, not terribly loud, but loud enough since the Bose EQ adds a bit of signal. Got to a Rolling Stones song and the speakers started making a loud crackle with the loud bass notes, king of sounded like someone was taking a drum stick and hitting the voice coil along with the bass notes. I ran to turn it down, no damage or anything, but is this clipping?

This is with my Marantz 2270, switch to the Sansui 9090DB, I can go way louder into 100 watt territory w/o those nasty sounds.

The Bose 901 guzzle watts like we drink water...

I know, get new speakers...
 
Ah yes. You have answered yourself. That is definitely clipping. If you can turn it up that much your speakers are way to power hungry.
 
Clipping is an amp. problem, this is something else.

"Clipping" is an amplifier reaching beyond its limits, "over excursion" is a speaker reaching its mechanical limits, both can occur at the same time or at different times.

What you may be hearing on the woofer is the voice coil "bottoming out" on the magnet assembly and if this is continued, you will have permanent speaker damage as the coil form is then flattened and will rub in the air gap and will have to be re-coned.

This is not to say the amp. isn't clipping too, but sounds like over excursion to me.:scratch2:

Amp.clipping sounds like record mis tracking and adds a harsh grating tone to the sound.

A friend complained about a harsh midrange and found he had is EQ set for the "smiley face" setting and I took a small scope to measure his system and told him to ether lower the EQ settings or he needed more amplifier power.

He got a bigger amp. and lowered the EQ settings and is happy now.:yes:

Mark T.:music:
 
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I had a speaker bottom out and it sounded simular to your symtoms.
I would take a look at your surrounds on the woofers.
Aged surrounds loose their compliance and can cause
greater excursion.
They dont have to be cracking or comming apart to be bad.
 
Use the FILTER switches

Clipping will usually affect the HF drivers rather that the woofers. Clipping will sound more like metalic excessive noise on top of the HF passages.

But, excessive mechanical sounding noise (cracking; knocking, etc.) on loud bass passages is usually those woofers hitting the limits of the voice coil excursions. This will damage the voice coil(s).

Of course, both can happen at the same time. It's best to test with those LOW & HIGH filters 'on', one at a time, to see which end of the audio spectrum you're messing with :yes:.

Paul
 
...

But, excessive mechanical sounding noise (cracking; knocking, etc.) on loud bass passages is usually those woofers hitting the limits of the voice coil excursions. This will damage the voice coil(s)....

Paul

That's what I thought, as well. The sharp whack sound of a drumstick is over-excursion.
 
I'm gonna have to not agree with what all I've heard here as to wether it was excursion or clipping...

I'm gonna go with clipping, and I'll tell ya why...

First off.. Bose 901's will take an insane amout of power. They were meant to be driven hard.... I can't see that amp pushing anything near the wattage needed to cause excursion on those speakers... you can damn near plug them into a wall outlet, and it shouldn't cause them to reach their limits..

Secondly.. I was just clipping the amp that drives my subs this morning.. They sounded very similar to what he is describing.. I know in no way was I close to the excursion limits.. I was only pushing about 300 watts into them tops.. they are rated at 700 program.. I've had them a lot louder before, and they sound fantastic.. until my amp starts clipping.. then they sound like crap, and somewhat metalic...
 
Ouch

I'm gonna have to not agree with what all I've heard here as to wether it was excursion or clipping...

I'm gonna go with clipping, and I'll tell ya why...

First off.. Bose 901's will take an insane amout of power. They were meant to be driven hard.... I can't see that amp pushing anything near the wattage needed to cause excursion on those speakers... you can damn near plug them into a wall outlet, and it shouldn't cause them to reach their limits..

Secondly.. I was just clipping the amp that drives my subs this morning.. They sounded very similar to what he is describing.. I know in no way was I close to the excursion limits.. I was only pushing about 300 watts into them tops.. they are rated at 700 program.. I've had them a lot louder before, and they sound fantastic.. until my amp starts clipping.. then they sound like crap, and somewhat metalic...


OK, I stand corrected - :scratch2: - for the Bose 901. Clearly any speaker able to suck up 450 watts should not be hitting the wall with a 70 watt amplifier driving it, except when it is clipping.

Paul
 
Thanks, this helps. At about this point in the volume level, my 9090DB is measuring about 80 watt peaks on the power meters, so it is possible I was pushing that much with the 2270 and at its limits. Later I plugged in the 9090DB and let it go up to 100 watt peaks with no problem. At this point, the lights in the meters were dimming with the bass (and the neighbor might have been screaming), so I did it for just a few seconds. The vol control was at 10-11 o'clock also.

Given the bassy propensity of the 2270, it was probably clipping while the 901s sucked the power out on the bass.

On a side note, the G is finding a new home today.
 
Thanks, this helps. At about this point in the volume level, my 9090DB is measuring about 80 watt peaks on the power meters, so it is possible I was pushing that much with the 2270 and at its limits. Later I plugged in the 9090DB and let it go up to 100 watt peaks with no problem. At this point, the lights in the meters were dimming with the bass (and the neighbor might have been screaming), so I did it for just a few seconds. The vol control was at 10-11 o'clock also.

Given the bassy propensity of the 2270, it was probably clipping while the 901s sucked the power out on the bass.

On a side note, the G is finding a new home today.

Cool.. glad this worked out for you...

I had to giggle a little bit like a school girl when you mentioned the meter lights dimming whith the beat of the bass.... I know this feeling.. only I watch the lights in my living and dining room do the same thing.. almost to brown out levels... not good..:no:
 
I confirmed that the clipping is in the left channel, I hooked up the CWs that take a lot of power and could only get to about 10-11 o'clock with that nasty noise. Now this was loud and only happened on the left channel. This channel, along with the other got new input transistors, driver pairs, and ouput transistors. Now I could not get the bias below 9 mV (5mV target), but the offset was right on. Wonder if maybe I got a faulty output, since they are made in China, and we know the QC issues that have been in the news lately.

You'll got any ideas?
 
It is clipping

Yeah, that sound is definatly clipping. I need a bigger amp for my subwoofer, and when I turn it up loud it clips. Clipping is caused when the amplifier cannot power the speaker/sub as loud as you want. When you crank it too loud, the amp struggles to get that much power to the speaker, and when its just too much it stresses and sends a Square sound wave to the driver. A sqaure sound wave will kill your driver if you continue to let it clip. Square sound waves are bad for any driver. What happens is the amp stresses out, and sends a large surge of power to the driver. This throws the voice coil out of the gap in the magnet for too long, and that hurts the voice coil. This is also bad for the amp, because the amp can overheat, and can light on fire. Make sure to turn the amp off when it clips and give it a minute to cool off, not that long. About a minute. Another thing. Check the impeadence of your speakers. Make sure they go within the amps range, because the lower the impeadence, the easier the power can go into the speaker, and if it is too easy, the amp will overpower itself because all that power is just slipping though. Too high and the amp will struggle to get the power to the woofer. Lastly, if the clipping is produced by the sub, turn down the gain to about a quarter, never full, and turn up the bass on the receiver to your liking. This will keep the clipping rate down and the SPL up.
 
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