Amp clipping lights please!

[creyc 10+ year member]

When a full range amp, connected to a full range speaker starts clipping, its glaringly easy to distinguish. You would have to be mad to let the amp continue to clip, it's so obvious.

But on a low frequency subwoofer it can be more difficult to detect. Couple this with rattling body panels, mirrors, and all that fun stuff and you can easily start damaging equipment without knowing.

A solution would be to play a -0dB sine wave and set the gain, so that it's impossible to play a note above the point of clipping. Well this is fine but every song is different, so an EQ can help boost or cut the bass as needed. But this of course removes that safety net you created when carefully setting the gain to prevent clipping, as it's now possible to over drive the amp. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

I need a clipping indicator, right there with the EQ, to provide a solid foolproof indication that all is not well, and its time to back off on the EQ before speakers start smoking. Why is this not built into amps? It could be coupled with a remote bass controller, in the same interface, even as a light on the bass controller itself.

Point is we need clipping lights, and we need them to be remotely visible. Almost all professional audio amps have this feature, why can't this be standard on car amps too?

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[phyphoestilic 5,000+ posts]

The Hifonics BX1500D i had, had the protect light on the bass knob, but it doesnt really show cliping.

 

[BassAddictJ 5,000+ posts]

good point man.....

sadly i do recall haveing an audiobahn a1300hct "1200w" (more like 800w), that one the remote bass knob would flash from blue to red if the amp was being drivin to hard......now thats ****ing ironic that audiobahn went ahead and did that. i wish real car audio companies did that more too....

 

[thch 10+ year member]

at one time i was concidering making a clipping light. never made it too far.

there are several ways to do things like this, but the simplist i've come up with is to build a twin-t bandstop filter @ 60hz, then play a 60hz tone. its about $1 of parts. the idea is that when you play a 60hz tone, and reject 60hz, all that is left is distortion and noise.

a twin T is a low-quality notch, and IIRC 180hz is -6dB down. and the notch itself may only be -40dB @ 60hz. so with 40V out you might see 400mV, and once clipping set in it might read 500mV.

it really shines with an oscope as, in the resulting signal, the distortion is readily visible as changes from a straight line instead a flatter top to a flat sine wave...

 

[60ndown 10+ year member]

wouldnt setting the gains where you want them with a dmm GUARENTEE no clipping?

edit; reading op pwns me

 

[60ndown 10+ year member]

A solution would be to play a -0dB sine wave and set the gain, so that it's impossible to play a note above the point of clipping. Well this is fine but every song is different, so an EQ can help boost or cut the bass as needed. But this of course removes that safety net you created when carefully setting the gain to prevent clipping, as it's now possible to over drive the amp.

use the dmm, dont use the eq=solution.

i keep all setting 'flat' and use 'level controll' for the sub not 'bass boost' etc.

i guess regardless of what we try, bass is addictive, we will turn it up eventually and require a re-cone or a new sub.......subs.

eventually

 

[creyc 10+ year member]

use the dmm, dont use the eq=solution.
i keep all setting 'flat' and use 'level controll' for the sub not 'bass boost' etc.

i guess regardless of what we try, bass is addictive, we will turn it up eventually and require a re-cone or a new sub.......subs.

eventually

Well, use a DMM, your ears, etc...thats the easy part. But then when you play back music with a relatively weak bass line, you can safely bump the 50Hz knob on the EQ and still not be in the clipping territory. But then if the next track is from a bass test CD or some hip hop, you're gonna have to quickly turn it down.

It would just be nice to have a feedback in the form of a glaring LED to "remind" you when you're in the red.

It isn't too surprising to find on Audiobahn gear I suppose, when you look at the average Audiobahn customer who probably isn't an enthusiast but just likes bass. They may not know what's wrong, but seeing a red warning light is a warning sign to even the inexperienced. In my case it's more a matter of constantly trying to get the best performance from my system, together with trying to keep the car on the road and not be 100% focused on watching for clipping. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

 

[Immacomputer 10+ year member]

This is what I do:

I first set the bass control on my headunit to 0. I then set the gains using my ear at around 60-70hz with no crossovers. Clipping is blatant at these frequencies to my ears. Once I find my max, I check the sub for mechanical problems across 20-80hz. If the sub unloads or is being over driven, I play that tone and adjust the gain accordingly.

After that is said and done, I sit in the car and play multiple slow sweeps and get used to what the max output sounds like for the sub. I then play test tones at 0dB and get used to it's output. Then when playing music, I have a good idea of how much I can boost the sub control.

Doing this, I have yet to have a driver fail on me thermally after about 8 years of being involved in car audio.

 

[Raven 10+ year member]

there are several ways to do things like this, but the simplist i've come up with is to build a twin-t bandstop filter @ 60hz, then play a 60hz tone. its about $1 of parts. the idea is that when you play a 60hz tone, and reject 60hz, all that is left is distortion and noise.

http://www.allaboutcircuits.com/vol_2/chpt_8/5.html

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