Clipping
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=83365
Printed Date: May 18, 2024 at 8:16 AM
Topic: Clipping
Posted By: soultinter
Subject: Clipping
Date Posted: September 26, 2006 at 8:29 AM
This is probably a little dumb, but I need a thorough explanation of Clipping and exactly how to recognize it. It seems that this is the #2 cause of subwoofer failure and I feel like i don't properly understand the situation and how to explain it. Thanks for being tolerant.
Replies:
Posted By: aznboi3644
Date Posted: September 26, 2006 at 8:35 AM
Go to www.bcae1.com
right hand side..find it...and has a lot more you can learn
Posted By: bellsracer
Date Posted: September 26, 2006 at 12:10 PM
Clipping is taking the electrical signal and pusing it beyond the abilities of the component. A speaker works by alternating the positive and negative back and forth to move the speaker and make sound. (Alternating current or AC) Using an oscilloscope you will see that the signal is a smooth curve (wave) that moves up and down. Clipping is taking the signal and putting a flat spot in the curve. ie DC current. When DC occurs during the AC power wave it is "clipping" the peaks and valleys off the wave. How this affects speakers is that the speaker will get to the power waves clipping point. (Say on the peak) Then the DC kicks in and "kicks" the speaker sideways. Then when AC continues on the wave, the speaker's voice coil is still kicked sideways and grinds down the pole and magnet structure's wall. Then at the other end of the wave (the valley), the clip kicks in again and kicks the speaker the other way. AC continues and grinds the voice coil up the other side. Now do this at 50Hz and now your speaker is grinding the voice coil 100 times per second. Bye Bye speaker. Now many shops will do their gain setting by ear by listening to when the speaker starts grinding at the wall. The truth of the matter is that, if you are already hearing the grinding, then there is at least 15-20% distortion and possibly damaging the speaker. A little saying that many of the uber-veterans (those who have been doing this since the 60s - 70s) will tell you that if you can "hear" the beginning of the clip, you can hear grass grow. They once proved it too by asking a bunch of shops to gain set the amps. When the oscilloscope was taken to the amps afterwards, 98% of them at at least 15% distortion and clip on the signal. Best way to maximize your power and keep the clip from entering is to use the oscilloscope. It'll show you exactly how much clipping you have. Just add or lose gain until you are right at the edge of making a clip. Maximum power without the clip. Hope this helps. Good Luck! aznboi3644 wrote:
Go to www.bcae1.com
right hand side..find it...and has a lot more you can learn
We found various mentionings of clipping and a rough description of overpowering an amp creates the clip, but nothing specifically describing the clip. Where did you find it here? ------------- Never send your ducks to eagle school.
The difference between ordinary and extraordinary is that little extra.
The 3Ls of life: Learn from the Past, Live for the Present, Look to the Future.
Posted By: sprawl85
Date Posted: September 26, 2006 at 12:33 PM
Just buy quality amplifiers that dont' clip. I have seen a lot of amps that I couldn't get to clip if I tried. Or keep some ED subs around because if you send a clipped signal to them it sounds like someone is beating a piece of sheet metal because of high tight the gap is on them.
edit: I forgot the original question by the time I posted this, but I figured I'd add my 2 cents anyway since you already got a technical definition.
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fiberglass reminds me of peanut brittle... but fiberglass tastes better!
Posted By: DYohn
Date Posted: September 26, 2006 at 1:08 PM
Uh, bellsracer, a DC signal will not "kick the speaker sideways." Where did you get that? The real danger of a clipping amplifier is the power delivered by a clipped signal can be several times the expected power level of a non-clipped signal and speakers can be blown due to overpower. Here's some resources: https://www.bcae1.com/2ltlpwr.htm, https://sound.westhost.com/clipping.htm ------------- Support the12volt.com
Posted By: bryantobando
Date Posted: September 26, 2006 at 1:44 PM
Clipping is like jumping on a bed with a low ceiling. If your bed is really spring (in this case, the amplifier is really powerfull and the speakers can't take it), when you jump, you'll hit your head on the ceiling. Though, if the ceiling was higher, you would have more head room and you wouldn;t hit your head. (in this case, your speakers can handle the power the amp is outputting). That is why you get those flat peaks on the waves on an oscilliscope. Its a wierd explanation, but that is how they tought me and it made more sense. But it has nothing to do with DC signal.
Posted By: haemphyst
Date Posted: September 26, 2006 at 3:04 PM
bellsracer wrote:
Clipping is taking the electrical signal and pusing it beyond the abilities of the component. A speaker works by alternating the positive and negative back and forth to move the speaker and make sound. (Alternating current or AC) Using an oscilloscope you will see that the signal is a smooth curve (wave) that moves up and down. Clipping is taking the signal and putting a flat spot in the curve. ie DC current. When DC occurs during the AC power wave it is "clipping" the peaks and valleys off the wave.
There is no "putting" a flat spot on the waveform. An amplifier is built with a given, set voltage, both positive and negative, called "rails". When the input signal tells the amplifier to "turn on" more than the rails are capable of producing, the waveform is "clipped off". That is what clipping is.
bellsracer wrote:
How this affects speakers is that the speaker will get to the power waves clipping point. (Say on the peak) Then the DC kicks in and "kicks" the speaker sideways. Then when AC continues on the wave, the speaker's voice coil is still kicked sideways and grinds down the pole and magnet structure's wall. Then at the other end of the wave (the valley), the clip kicks in again and kicks the speaker the other way. AC continues and grinds the voice coil up the other side. Now do this at 50Hz and now your speaker is grinding the voice coil 100 times per second. Bye Bye speaker.
There is one I have NEVER heard before. Where did you get that description from? I did tell you I'd call you on anything...
bellsracer wrote:
Now many shops will do their gain setting by ear by listening to when the speaker starts grinding at the wall. The truth of the matter is that, if you are already hearing the grinding, then there is at least 15-20% distortion and possibly damaging the speaker. A little saying that many of the uber-veterans (those who have been doing this since the 60s - 70s) will tell you that if you can "hear" the beginning of the clip, you can hear grass grow. They once proved it too by asking a bunch of shops to gain set the amps. When the oscilloscope was taken to the amps afterwards, 98% of them at at least 15% distortion and clip on the signal.
Best way to maximize your power and keep the clip from entering is to use the oscilloscope. It'll show you exactly how much clipping you have. Just add or lose gain until you are right at the edge of making a clip. Maximum power without the clip.
You are correct... The BEST way to set gains is with an oscilloscope, but not everybody has a 'scope sitting around in their garage! I do, and I use it, but clipping is quite the audible distortion... An o-scope is not always necessary. I can PROMISE you, that if I were set in a car I would be able to hear the onset of clipping, pretty much immediately. I can hear clipping in a recording, even if the amplifier is NOT clipped.
sprawl85 wrote:
Just buy quality amplifiers that dont' clip. I have seen a lot of amps that I couldn't get to clip if I tried. Or keep some ED subs around because if you send a clipped signal to them it sounds like someone is beating a piece of sheet metal because of high tight the gap is on them.
edit: I forgot the original question by the time I posted this, but I figured I'd add my 2 cents anyway since you already got a technical definition.
There is NO SUCH THING as an amplifier that can't be clipped. ANY amplifier, if pushed beyond it's capabilities can be driven past the rails, resulting in clipping!
bryantobando wrote:
You are prolly clipping because you have the volume or the gains of the amp all the way up. You should turn up the volume and gains maximum 3/4's up.
MORE wrong information. The "gain control on an amp is NEVER "just set". It should always be adjusted carefully, first by ear, then with instumentation, if available.
bryantobando wrote:
Clipping is like jumping on a bed with a low ceiling. If your bed is really spring (in this case, the amplifier is really powerfull and the speakers can't take it), when you jump, you'll hit your head on the ceiling. Though, if the ceiling was higher, you would have more head room and you wouldn;t hit your head. (in this case, your speakers can handle the power the amp is outputting). That is why you get those flat peaks on the waves on an oscilliscope. Its a wierd explanation, but that is how they tought me and it made more sense. But it has nothing to do with DC signal.
Another pile of "clipping crap". Clipping is an INTERNAL ELECTRICAL condition, it has NOTHING whatsoever to do with anything mechanical or external. The jumping on the bed analogy is completely wrong. ------------- It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: kfr01
Date Posted: September 26, 2006 at 9:06 PM
Thank god for haemphyst.
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New Project: 2003 Pathfinder
Posted By: stevdart
Date Posted: September 26, 2006 at 10:48 PM
kfr01] wrote:
hank god for haemphyst.
Read and learn, people. Help keep this forum at the top of the information food chain where it's been since '02. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: bellsracer
Date Posted: September 27, 2006 at 3:30 AM
DYohn] wrote:
P>Uh, bellsracer, a DC signal will not "kick the speaker sideways." Where did you get that?~snip~
Like I said in earlier posts, the owner of the shop likes to play with every dynamic possible. He has a friend in the structure dynamics business and he wanted to see exactly what a sub is doing during a clipped signal. While studying the high speed, the sub wants to go further (newton's law) but lacking the energy to do so the mass wants to keep moving forward but due to the flat response in the power the mass shifts slightly. This usually occurs at 25% THD on the signal. As for DC on the wave form. Like I said, a DC form will show up on the scope during a clip. DC on an oscilloscope will just show up as a flat line. During a clipped signal, the flat line shows up in the wave. haemphyst, thanks for the heads up and no grudge. Reading your post is right. I was trying to describe it without getting technical. Well w/e. Like a couple of others, I was trying my best to describe what is going on. I guess I'm just not as good. ------------- Never send your ducks to eagle school.
The difference between ordinary and extraordinary is that little extra.
The 3Ls of life: Learn from the Past, Live for the Present, Look to the Future.
Posted By: stevdart
Date Posted: September 27, 2006 at 5:07 AM
soultinter, there have been several threads in this forum that covered the subject of clipping. Find them by looking for the word "clipping" in the subject as a forum search. Here is one to start with. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: forbidden
Date Posted: September 27, 2006 at 6:16 PM
bellsracer, that indicates a failure in the spider more than anything else. In that case the speaker is being played beyond the mechanical limits of the drivers design and would not be a function of clipping. A speaker can be played beyond it's mechanical limits with a non clipped signal as well. If the cone is off centering at full excursion, be it a clipped or non clipped signal, this is indeed a mechanical failure.
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Top Secret, I can tell you but then my wife will kill me.
Posted By: soultinter
Date Posted: September 28, 2006 at 3:30 PM
Thanks for all the help guys, I'm still struggling with the concept but everything helps. Can I loosely say that clipping is a form of distortion?
Posted By: DYohn
Date Posted: September 29, 2006 at 1:49 PM
soultinter wrote:
Thanks for all the help guys, I'm still struggling with the concept but everything helps. Can I loosely say that clipping is a form of distortion?
Absolutely. Forbidden is 100% correct, if a loudspeaker is "kicking sideways" is has suffered some sort of mechanical failure. A DC signal (or a 100% clipped signal) will not cause a voice coil to move sideways unless the suspension system is compromised in some fashion. THEN Newton's laws may cause it to move in ways predictable by kinetic energy and gravity, and Faraday's laws can predict how movement might be changed due to magnetism. But a properly functioning suspension system will keep motor motion linear. ------------- Support the12volt.com
Posted By: s_p_n_k_r_07
Date Posted: October 17, 2006 at 12:35 AM
The method I use to understand how "clipping" effects the signal is...... the input voltage to the amp exceeds the amps abilities to amplify at the rate the gain is set at. Then the output of the amp is missing the very top and bottom of the sine wave, it basicly "clips" off the stuff it cant reproduce. Now were taking a nice rounded curve and adding abrupt changes. This adds heat to the motor structure of the speaker. Because its just doing what its input is telling it even though its not acting the way it was designed. A speaker recieving a clipped signal is like running and hitting a brick wall and then having to run away from the wall at the same speed of impact instantly. (pretty difficult) with a signal that has its natural sweep it would be like.... running into a rubberband and having the gradual slow to a stop and then having it help you return the opposite direction. well at least it makes sence in my head, now that i'm reading it its not as enlightening as I thought. but worst case you will all get a good laugh at my expence and well all be friends in the morning. clipping is the devil, and so is distortion. just say no to noise in general.
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