Crackling Speakers

falcon

Active Member
I do sound and lighting for a church group on sundays and they are complaining about crackling in the speakers. I think its just the drivers in the speaker that are going, but they really want me to fix it. Is there any other reasons for this to happen?

Also, since we put in the new sound board and eq, the sound seems to be quieter, i have to set the level for the wireless mic at max. Is it just me, or does the sound level drop like that from the eq? Or the eq isn't properly set up, I didn't set it up myself so i don't know. Any suggestion?
 
we had a problem with our eq's. the bypass swtich for the master volume on them go pushed and the level turned down so we didnt get any through it. you may want to check that.
 
There is a good chance its the drivers. You might want to consider taking the grill off, and pushing the cone in SOFTLY by hand. If you hear a rubbing noise, chances are that the driver is starting to go, or has gone already.

As for the problem with the levels, bypass the EQ completely, and see if the problem persists. If so, check the gain on the channel/mic reciever/any other processing gear in the line.
 
Is the problem in all of your drivers, or just in one box?

If it is just in one box, swap them over and see if the problem remains in that box or is now in the one with which you swapped it. If this is the case, it is not the speaker.


In testing – I would first remove all the effects and processing gear from the signal path. If it were me, I would actually plug a signal generator directly into the amp and power it up at a low frequency (longer wave form and therefore longer travel on the cone).

If you do not have a signal generator, you can download programs that will do this for you and run off of a computer or just use a CD player. I have a box with a 2 gang 10K pot that I use to test older amps that do not have volume controls on them. Essentially, you want to limit the number of potential problems in the signal path. Every connector, cable and piece of equipment is a potential cause for fault.

Once you have run the speakers off of the amp and there is no crackle or other obvious problems, I would then run the signal through the desk and then use a mic and then add in the other equipment piece by piece. Also swap over cables if any test fails and explore the cable issue before proceeding to the next step.

If you do push on the speaker, make sure that you apply even pressure or you will cause the speaker to rub due to the angle at which you are pushing it, rather than have it rub due to damage that is already there. The rub is generated by either the spider failing (the corrugated disc that sits at the bottom of the cone and holds the cone in a central position), there is damage to the voice coil or the lacquer that coats the voice coil has blistered (due to excessive heat) or some crap has fallen between the voice coil and the former. If this is the case, the speaker can be repaired and it may be worth having them inspected by a repair company. Try to find one that only deals with speakers as opposed to a general tech outfit that can also repair them.
 
as i said, the group was complaining about the crackling, i didn't hear it myself. but when i played a cd there was no crackling. I then plugged in a mic directly into the board and there was nothing out of hte ordinary from that. I think its just the mic they were using. Last week it was cutting in and out while he had his hand in his pocket htat teh transmitter was in, so i'm thinking there might be a broken wire, in which case i've told them to buy a new mic anyway.

If that isn't the problem, i cna't get to teh speakers easily, and i am leaving at the end of teh summer so it doesn't matter to me a whole lot that the speakers aren't top of the line.
 
falcon said:
as i said, the group was complaining about the crackling, i didn't hear it myself. but when i played a cd there was no crackling. I then plugged in a mic directly into the board and there was nothing out of hte ordinary from that. I think its just the mic they were using. Last week it was cutting in and out while he had his hand in his pocket htat teh transmitter was in, so i'm thinking there might be a broken wire, in which case i've told them to buy a new mic anyway.

If that isn't the problem, i cna't get to teh speakers easily, and i am leaving at the end of teh summer so it doesn't matter to me a whole lot that the speakers aren't top of the line.

There could be a number of things they are hearing.... If youdon't hear the speakers breakingup when you push them hard on a CD--then it leads me to think that its something else breaking up. Not sure--I would have to hear it in use to tell if its electrical, physical or what it is...and look at how the system is set up.. If you are using wireless lavs--that could be a problem right there. Aside from loose connections and wires--the mic could simply have too much gain and be distorting...or if you are using a regular lavalier that is designed for speech--if someone YELLS into it, it can overmodulate and distrort and break up--which would sound like crackling. Lav's for speech typically do not have a high SPL rating like a lav used for Signers or Gospel Preachers...and that could be your problem and the speakers are fine. However--if that crackling keeps up, you could damage or destroy your high frequency drivers very quickly....

As for your question on the signals dropping dramatically with a new console--sounds like the EQ and gain structure of the system is not set correctly... You should never have to open your gains to max--either your input levels is wrong or the EQ after the new console is the culprit and EQ is set too low...

JMO...
-w
 

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