Help troubleshoot "sick" QSC CP8 speaker.

[Daniel Grenier]

I have 2 QSC CP8 powered speakers. One is its usual self: sharp, crisp, clear. The other is very muddy, muffled and lacking in the hi freq. Both are set up exact same and mixer & cables have been checked. This is on all Contours and either inputs.

Any suggestions as to what might be the cause?


PS There is no warranty and no rattling or evidence of a torn/damaged speaker

Thanks...

[YamahaGuy]

Sounds like my Harbinger 15 did when the high frequency driver blew. Try sticking your ear right next to the top (of the two) speakers with something playing through it and listen for any sound coming from it. Then repeat for the bottom speaker. I'd bet the high frequency is blown. They blow. They can be replaced if you have a long enough phillips screwdriver, enough guts and patience, and about $35 for a replacement from Parts Unlimited.

[ljguitar]

Originally Posted by Daniel Grenier

…The other is very muddy, muffled and lacking in the hi freq.

Hi Daniel

Sounds like the high frequency driver is either disconnected or gone (as in passed-on).

[Daniel Grenier]

Originally Posted by YamahaGuy

... Try sticking your ear right next to the top (of the two) speakers with something playing through it and listen for any sound coming from it. .... I'd bet the high frequency is blown......

Well, sure looks you guys hit that nail right on the head! There is nothing coming out of the top speaker on the "sick" one and plenty out of the good one.

So, what part exactly do you mean by "blown"? The actual speaker? The HF circuit board? Something else?

Thanks, YamahaGuy and Larry. Much appreciated.

[YamahaGuy]

Originally Posted by Daniel Grenier

Well, sure looks you you hit that nail right on the head! There is nothing coming out of the top speaker on the "sick" one and plenty out of the good one.

So, what part exactly do you mean by "blown"? The actual speaker? The HF circuit board? Something else?

Thanks, YamahaGuy. Much appreciated.

Sometimes the driver itself blows. Other times it's the electronics in the amplifier part or even a crossover.
I've encountered this with two different powered speakers. On a Harbinger, I took apart the cab replaced the high frequency compression driver and all was well. On a Gemini Party speaker, I did the same thing and the problem was not resolved. It seems as though part of the amplifier went bad. Unfortunately, the cost of a new control board/amp was more than the cost of the speaker. For a $400 speaker, I'd roll the dice and buy something like this:
https://www.parts-express.com/eminen...8-tpi--290-525
and see what happens.

Sometimes the driver screws into the horn. The cabinets can usually be separated by removing a dozen or so screws and leaving the control panel in place.

Some pros are skilled enough to replace just the diaphragm in the drivers. For the price difference, I just go with the complete driver.

[mandowilli]

You could swap the HF drivers from one speaker to the other before buying a replacement to see if it is in fact blown.

We have a lot of time on our hands now, right?

[Daniel Grenier]

Well, you do learn something new every day. Today I leaned how to take my QSC CP8s apart! The HF speaker is indeed blown and needs replacing (I swapped the bad for the good and sure enough ....).

Anyway, QSC does sell it for a mere (and oddly priced) $32.56 usd - but - they do not sell to end-users outside the US so I'll have to find and go thru a Canadian dealer that does sell parts.

Thanks again for the pointers, folks.

[YamahaGuy]

Originally Posted by Daniel Grenier

Well, you do learn something new every day. Today I leaned how to take my QSC CP8s apart! The HF speaker is indeed blown and needs replacing (I swapped the bad for the good and sure enough ....).

Anyway, QSC does sell it for a mere (and oddly priced) $32.56 usd - but - they do not sell to end-users outside the US so I'll have to find and go thru a Canadian dealer that does sell parts.

Thanks again for the pointers, folks.

Good job!!!

[MarkF_48]

Daniel, maybe try contacting Full Compass and see if they could order it for you. They are an authorized QSC dealer for parts as well as for other manufacturers.
I did look for the CP8 driver on their site, no luck.
Full Compass Pro Audio

[Daniel Grenier]

For those interested or anyone facing the same issue, here are some pics of the speaker and parts in question. The "blown" part is the HF diaphragm which is basically a flimsy-looking plastic(y) film that sits inside a small but strong magnet. Kind of impressive, actually, considering how incredibly loud this thing can get.

The QSC part number is XD-000105-01 for the diaphragm (called Compression Driver" by QSC). It is listed on their website as "in-stock" and selling for $32.56. But, know that they do not sell to end-users outside the US. You have to contact your country's QSC dealer for it.

Tearing down the speaker is pretty straight forward.

• Go from the front and remove the grill (4 screws and lightly pry the grill out)
• Remove all the screws around the perimeter (leave the main speaker in and do not remove the 4 screws around the HF yet).
• Gently pull out the speaker module but mind the rather short speaker cables that are tied to the amp.
• There is very little room to disconnect the wires and the connectors have a small "push button" you need to squeeze to get the wires out.
• The wires are color coded so write down which is which
• The module can then be pulled right out and the four screws at the from removed to access the HF module
• The diaphragm can be removed by taking the 4 silver screws out but be aware that there is a very small and barely visible plastic spacer in there too.

Anyway, hope this helps...

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[stephenT]

Thanks for this. Used your instructions to change out the tweeter in my CP-8.

I was able to replace the tweeter without disconnecting the woofer wires and completely removing the baffle but that was my only deviation.

Much appreciated.

[jonfields45]

I wonder if anyone sells a Neodymium replacement for the 8” woofer… Could take a few pounds off. I’m a guitar hobbyist, not carting hobbyist

[edward993]

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