I bought a pair of Mission 760i speakers a few months ago from UK Ebay.
After like 2 months of having them, one of the speakers suddenly started putting out this ugly sounding air current through the front port, its like a crackling noise. It sounds the most obvious at about 50Hz in tone generator, but the crackling sounds higher pitched than the bass coming out and the crackling noise disappears if i lower the volume enough.
I have sent the broken speaker to two different places to fix it, before troubleshooting them myself because i was lazy and thought i didnt have the expertise/confidence to do it myself.
The first guy thought it was the woofer fault and took apart the woofer and changed the coil because he said it was deformed/ egg shaped or w/e, but it didn't help the crackling noise, its still there.
The second place told me its the faulty tweeter that's causing a vibration. They fixed nothing and charged me 20euros for trouble shooting.
After i got it back from the second place, i had built up the courage to troubleshoot and take them apart myself.
So, I tried switching every component(woofer+tweeter+xover) of the crackling speaker with the normal sounding one. And the crackling noise still persists in the same broken speaker. I tried taking out the dampening foam from the cabinet but it didn't help.
I ordered film caps, but they wont help as i have already switched the xover from the good speaker and it didn't help.
Is there anything else left to try?
After like 2 months of having them, one of the speakers suddenly started putting out this ugly sounding air current through the front port, its like a crackling noise. It sounds the most obvious at about 50Hz in tone generator, but the crackling sounds higher pitched than the bass coming out and the crackling noise disappears if i lower the volume enough.
I have sent the broken speaker to two different places to fix it, before troubleshooting them myself because i was lazy and thought i didnt have the expertise/confidence to do it myself.
The first guy thought it was the woofer fault and took apart the woofer and changed the coil because he said it was deformed/ egg shaped or w/e, but it didn't help the crackling noise, its still there.
The second place told me its the faulty tweeter that's causing a vibration. They fixed nothing and charged me 20euros for trouble shooting.
After i got it back from the second place, i had built up the courage to troubleshoot and take them apart myself.
So, I tried switching every component(woofer+tweeter+xover) of the crackling speaker with the normal sounding one. And the crackling noise still persists in the same broken speaker. I tried taking out the dampening foam from the cabinet but it didn't help.
I ordered film caps, but they wont help as i have already switched the xover from the good speaker and it didn't help.
Is there anything else left to try?
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Is there anything inside that cabinet touching the back of the woofer cone?
What do you get if you run each woofer in free-air?
Chris
What do you get if you run each woofer in free-air?
Chris
There is nothing that could be touching the back of woofer cone. Both of them sound normal when ran in free-air.
I took the tweeter out, put my hand inside the cabinet and checked, the woofer wires aren't touching the plastic. I had tweeter disconnected and its wire duct taped to the back panel during this.
I have also had some annoying sound from screws not at the right toutque (usually 1 overtightened). The crews should not be overnight. Just enuff to ensure a real or imaginary washer under the screw head no longer turns.
dave
dave
Loose wood joint somewhere? Or the cup on back is loose. Stray screw loose inside the box?
Can you play the speaker with your hand inside the tweeter hole, and poke around
to see if you can affect the noise?
Can you play the speaker with your hand inside the tweeter hole, and poke around
to see if you can affect the noise?
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The screws on the untinkered speaker, i didn't send anywhere, were super tight, when putting back the drivers i couldn't even get them as tight as they were before, but it sounds ok.
The cabinet doesn't feel flimsy or leaks air from outside when playing.
If i take out the tweeter the crackling noise seems to disappear completely, if i put my hand inside that tweeter hole its hard to tell whether the sound changes from the way my hand is positioned and blocking the air or because i'am poking something, but nothing feels flimsy from inside either.
I think about putting glue on the wood joints inside as last ditch effort.
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If the speaker has a plastic baffle, it might of come loose from the wooden box.
Lie the box on its back, on top of a blanket, then while running a test tone at the frequency that makes the cracking noise, use your hands like clamps on the baffle and sides to see if that stops the cracking noise.
Lie the box on its back, on top of a blanket, then while running a test tone at the frequency that makes the cracking noise, use your hands like clamps on the baffle and sides to see if that stops the cracking noise.
I tried this, i pushed on them down with all my weight, not a slightest change.
Maybe i just should stuff the port and listen to them that way and be done with it, because stuffing the port with a sock stops the crackling. And it seems that the normal sounding speaker sounds cleaner with stuffed port as well.
Did you change the connectors at the back of the box? It may be a problem with the terminal.
Measuring the impedance curve of both speakers could be useful too.
Measuring the impedance curve of both speakers could be useful too.
Crossover is mounted on the terminal cup, and i have switched it already with the normal sounding speaker, the crackling still persists in the same cabinet.
Bought polyester wadding that I'm gonna try filling the cabinet with and see if it helps.
Did you change around the channels of your amp? May be an amp problem, too.
I had such "cracking" problems with loose contacts and very old, dryed out electrolitic capacitors.
The cabinets of these speakers seems to small to produce any sound by them self.
If you close the reflex port, the movement of the bass driver is reduced in some frequency range.
If there was a large leak, the opposite could happen with the driver having more excursion than in the other box.
Maybe make a recording of the noise and load it up, this would sure help to identify the problem.
I had such "cracking" problems with loose contacts and very old, dryed out electrolitic capacitors.
The cabinets of these speakers seems to small to produce any sound by them self.
If you close the reflex port, the movement of the bass driver is reduced in some frequency range.
If there was a large leak, the opposite could happen with the driver having more excursion than in the other box.
Maybe make a recording of the noise and load it up, this would sure help to identify the problem.
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