How to tell if the singal or amp, or speakers, is clipping?
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Posted on Sep 28, 2005 02:02 pm
Bryan316
Member Since: Sep 23, 2005
Just wanted to see if you guys know how to tell where clipping/distortion is coming from? For example, if a mic is clipping, your mixing board will usually see it. But if you send a clean signal to a power amp and speakers, what does it sound like when the amp is getting too strong of a signal (assuming the power amp has no clipping lights, or you can't see them)? What does a farting or peaked out speaker sound like compared to a peaked out amp? Sometimes, if I'm sending a really bass-driven signal, I can't tell if I've turned the signal up too loud for that amp, or if I'm blasting the speakers too loud.
Thanks.
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Sep 28, 2005 07:18 pm I would look at the specs and figure out what the maximum signal that the amp/speaker can handle.
If the amp has any protection built in at all, it should shut down when things are getting to hot.
If the amp is clipping, it will sound distorted. Take a look at the input sensitivity of the amp (maximum inout signal before amp clips) and compare it to the maximum output of your mixer. If you shove a limiter after your mixer and calibrate it to your specs, you'll be sweet.
Also, if you are sending an already clipped signal from the mixer or if the signal is being clipped by the amp, the signal will become more of a square wave than a sine wave. Speakers are made to move in and out with the compression and rarefaction of a sine wave (think smooth curve). But if the compression and rarefaction of a wave are occuring simultaneuosly (square wave) the speaker will have to be in two places at once (+ and - stages). This will blow a speaker faster as well.
As a general rule, the Amp should be twice as powerful as the speaker.
I'm not really sure what a 'going' to blow speaker sounds like though. Hopefully someone else does though.
Hope this helps, but I see I haven't quite answered your question. haha
jmailjimmie neutronMember
Since: Feb 14, 2005
Sep 29, 2005 06:18 am The square waves of a clipped signal is what melts voice coils in speakers fastest. But too hot of a signal will also. You get no real "warning" of impending doom... it happens and then you go "what the..." and the audio sounds like kah-kah. As the colonel says, either way can do it. Once you hear the speaker sounding like crap, it is crap. It may not be "blown", but there is damage done.
Sep 29, 2005 07:36 am Actually, my speaker started to smell funny when it was about to blow. Of course, we all blamed the smell on the bassist, but then all of a sudden my P.A. sounded like the guy from "yellow submarine" ("In our yellow, submarine"). Maybe a 'smell' test is in order?
Rules:
1. If it starts to smell, check your bassist. If its not him, turn down your amp!
Sep 29, 2005 07:37 am :: sniffs under arms ::
Nope, not me...
Sep 29, 2005 12:52 pm HAHA! I'll remember to cover my speaker cones with Old Spice, then. That should give me some great sounds!!!
Allright, of course the logic would be to make sure all signals aren't peaking out, and send as even a signal from my main outs to the amp. But let's say, my board's level meter shows a nice green overall signal with a bit of orange, but definitely not lighting up the reds for anything more than a fraction of the time, if at all. Then I send that down to the amp, and I assume that the amp should be able to take it in comfortably. But, if the signal itself has a lot of woof to it or some other harmonics that's just sucking wattage, is it easier to tell if the signal's too hot when the power amp's volume is lower? Like listening to the signal first to assure it's clean, then cranking it up? I know from time to time, as you turn up the amp, the amp can start to clip cuz the low end is so loud but you can't tell when the amp is turned down. Then there's the speakers themselves farting or woofing when there's too much low end. I just want to know what the difference might be, so I can tell if I'm gonna pop something. Yeah, my amp right now has internal clipping to keep it from blowing, but those speakers can still fart out if this amp is too strong. I guess at this point, I'm just restating the obvious.
I've got the Dbx 266XL for protecting the mixer from the double bass drums, and to clean up my vocals and level myself out when growling up close or really high pitched or standing further away. I just can't stand when singers pull the microphone away form their mouthes when hitting high notes, so I figure I'll use a good noisegate/compressor to keep me at an even level and don't blow **** up when I give a good ol' banshee whail once in a while.
But I'm considering getting another compressor just to do that, and use this 266XL to protect the amp and speakers. How much should I realistically pay for, say, the 1046 to keep microphones in check? I doubt I'll really find one used any time soon. Musician's Friend (ugh) has them for $500. Is that the average price?
Noize2uCzar of MidiAdministrator
Since: Apr 04, 2002
Sep 29, 2005 06:49 pm Honestly you dont really need anything that expensive. A lot of people here make do pretty well with much lower priced compressor's. I would maybe have a look for another Dbx unit or something similar. Behringer has several excelantly priced unit's as well if you cant locate the Dbx for a reasonable price.
jmailjimmie neutronMember
Since: Feb 14, 2005
Sep 29, 2005 11:26 pm Another consideration is bi-amping (or tri-amping, depending on how expensive you want to get...) The idea there is similar to a cross-over to protect your horns, but you send the lows to one amp and some bass bins, and the rest of the program material to another amp and speakers. Also a similar concept to multi-band compression: the bass peaks do not interfere with the "performance" of the main portion of the program material. You have to be careful with cross-over points and speaker selections, but if you're wanting to out-do the Who (or whoever is the loudest and has "em-Plee-fi-ers that go up to eh-Lev-hen!") and push some dB's, you needs it, you needs it bad...
Sep 30, 2005 03:45 pm I really need a separate, more powerful amp, just to drive the two 15" no-name speakers in homemade cabs and just send the low-end to them. Right now, I'm paralleling the 15" woofer cab and a 15" Carvin main on each side. It doesn't let me push each separately. Ideally, I'm thinking an adequate and efficient setup would be:
(2) JBL JRX118S
(4) JBL JRX115 two on each side angled away to spread the sound across an audience
(4) JBL JRX112 one for each musician
And that alone is 2 grand without even considering the kind of mixing board, crossover and power amp I'd need to upgrade! I love going broke!
Sep 30, 2005 10:26 pm Quote:
I love going broke!
Don't we all.
Oct 20, 2005 01:45 pm start by setting EVERYTHING to unity gain....turn your poweramps all the way down first...set your master fader to zero, then the channel faders to 0db (not all the way down) now adjust your trim (gain) on the preamp....make sure that dosn't clip and you're in the good.
this is called gain staging, and is vital to good performance out of your gear.
cheers
wyd
Oct 20, 2005 01:48 pm or, turn everything off, point a microphone right straight at your speakers, turn all the knobs to 11 and powerup.
oh, wait, I meant DON'T do that.
Oct 20, 2005 01:52 pm HA!
jmailjimmie neutronMember
Since: Feb 14, 2005
Oct 21, 2005 02:10 pm What'd ya say? I can't hear you!... I tried to do what dB-Wan the Masters said to do!...
"Actually, he choked on his own vomit..."
zekthedeadcowEat Spam before it eats YOU!!!Member
Since: May 11, 2002
Oct 21, 2005 06:20 pm actually most poweramps will have a "protect mode" when they clip...ie they temporarially shut off...as opposed to permanently :) It could blow an internal fuse... I've only seen one instance of clipping a power amp and that was due to a congregation of idiots...vocals at a rock concert were too low a volume, and over driven, and if the vocalist really screamed the entire thing would cut out for a few seconds...because the power amps were running in sterio mode and only the left channel was plugged in...because "the sound people" didn't understand how bridged mono worked...so the left channel of a few power amps were running ...err... trying to run... the entire stage... of course after they quit in the middle of the show those of us who took over got blamed. :P
