Are My Monitors Blown????

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studioman

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when i turn up the volume,the woofer on my left monitors 'crackles' and 'distorts' with the bass kick and guitar.

its been producing a 'slight distortion' for about a week now but nothing as bad as today.

what can i do?

do i have to replace it?

any diagnosis?

monitors are event 20/20 bas

any input would be greatly appreciated.

thank you
 
That's a very bad sign. Remove the grille and look for tears in the cone or surround. Some materials used for the surrounds are subject to attack by pollutants and other factors (sunlight and humidity) that cause them to rot. If it looks ok, press gently on the surface of the cone to make it move in and out, keeping the pressure evenly distributed around the center of the speaker; if you hear and feel a crunchy or gritty sound, the voice coil has overheated to the point that the enamel has burned off, and that speaker will need to be replaced/reconed.

Twist
 
some other symptoms:

at certain points the woofer will completely loose power.

when woofer looses power pushing on the cone gives it power

sometimes theres no distortion

sometimes theres little distortion

sometimes theres a lot of distortion

there is no distortion at low volume

-----------------------------

taking your advice i pushed on the cone with the power off and it does make a 'gritty' sound where as the right speaker makes no sound.

if i have fried the voice coil,what could have caused it?

how do i go about 're-coning' the speaker?

thanks
 
Find a local place to re-cone your speaker. A good audio repair shop can tell you where to go.
If I were you I'd have both woofers done, to make sure you keep an even pair. Its not very expensive, and the speakers Event uses are bog standard, so most re-coning places will have them.
 
Just replaced a woofer in my 20/20's last week, that's the way it started out with some distortion and some crackles and then....silence. Didn't think of reconing the speaker, guess I could have it done and have a back-up on hand eh.
 
Reconing isn't such a good solution.

Repair shops usually use generic replacement components for a particular manufacturer and driver size. Speaker boxes and crossovers, however, are tuned to the parameters of a specific driver. Furthermore, original equipment manufacturers like Event will more often than not have custom components made for them by their suppliers. I think Event uses Vifa drivers, but it's unlikely they are completely off the shelf. Even so, it's still very unlikely a repair shop will have the exact cone assembly.

You're much better off ordering a new driver from Event.
http://www.digitalriver.com/dr/v2/ec_Main.Entry?SP=10007&SID=30181&CID=0&DSP=0&CUR=840&CACHE_ID=0

Definitely buy 2, if they sell them in matched pairs, or you think your other woofer is also failing. Otherwise there is no benefit, but you'll need to "break in" the new driver.

barefoot
 
Your "other symptoms" in your follow up post all indicate a fried voice coil. There's really only one cause for that - the speaker was over driven (too loud or too much bass) and it over heated. My first question is why didn't the other one suffer the same fate?
Maybe it just barely escaped because there was less low frequency energy present in that channel.

One other thing that can fry a voice coil is DC flowing through it. It simply cant dissipate that much heat. But the only thing that can cause that is a shorted output transistor(s) in your amplifier that places supply voltage across your speaker terminals! That doesn't sound like your situation though.

Concerning the reconing issue, with many off the shelf speakers, it's not that much cheaper than replacing it. I would think in your case you'd be better off replacing it to insure that it matches the other speaker. Barefoot summed that issue up quite nicely.

Twist
 
Twist,

You might be onto something regarding DC. But, it doesn't just have to be a blown transistor. I've downloaded a few wave files from free loop sites which had large DC offsets in one or both channels.

It's probably a good general practice to look at any sounds you download before you go cranking them through your system.

barefoot
 
barefoot said:
Reconing isn't such a good solution.
Click to expand...

Oh thanks for that wonderful information barefoot! I better go and tell just about every facility in the world that they are totally wrong in regularly re-coning their drivers!:rolleyes:
 
If we were talking about a $300 JBL model 22xyz driver for which the pro sound repair shop can wip out a JBL model 22xyz replacement cone assembly, then yes, by all means re-cone.

Currently we're discussing a $69.95 Event Electronics driver. It's better to buy the whole unit IMVHO.

barefoot
 
I won't bother, one day go and familiarise yourself with a studio, it might help
 
sjoko,

Is this an invitation? Are we becoming buddies? Because I’d love to learn how a professional studio is run. I'm sure you're busy, so how about just a one day intensive overview, poking around your studio and picking your brain. In return I’ll spend a day giving you an overview of loudspeaker design and manufacturing. ;)

barefoot
 
it´s quite easy to know if the driver is broken, but its kinda hard for me to explain how. Just try to gently push the cone with your hand. If it feels "funny" (just compare to the other speaker) its prob broken. I cant explain it better, sorry....
at least it works with 18" drivers...havent tried smaller ones, but it shouldnt be too much different i think.
 
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