QRX212 distortion

Rob Spence

Rob Spence

Senior
Jan 11, 2011
897
4
18
Boston Metro North West
www.lynxaudioservices.com
At a gig a few weeks ago, one of my four EV QRX212s had a high mid distortion. Changing amp channels did not change it nor (on the wild possibility of venue interaction) swapping cab with adjacent cab. Other than the odd distortion, the cabinet seemed to perform ok.

So, today I opened up the cabinet. Removed grill. Inspection showed the horn somewhat distorted at some of the mounting bolts. Since the gasket is pretty thin, perhaps an air leak interaction?

I pulled out the horn (after marking the up location) for further inspection. I found that I could easily take up about a full turn on each of the four bolts that attach the DH7 driver to the horn.

Ideas to try while it is open?

Suggestions?

Rob T, anything to add or clarify?



 
Hi
Rob Spence said:
At a gig a few weeks ago, one of my four EV QRX212s had a high mid distortion. Changing amp channels did not change it nor (on the wild possibility of venue interaction) swapping cab with adjacent cab. Other than the odd distortion, the cabinet seemed to perform ok.

So, today I opened up the cabinet. Removed grill. Inspection showed the horn somewhat distorted at some of the mounting bolts. Since the gasket is pretty thin, perhaps an air leak interaction?

I pulled out the horn (after marking the up location) for further inspection. I found that I could easily take up about a full turn on each of the four bolts that attach the DH7 driver to the horn.

Ideas to try while it is open?

Suggestions?

Rob T, anything to add or clarify?
Click to expand...

Hi Rob.
I've been using big horns for years. (2441's & 2445's anyone?)
Never had one work it's way loose.
I would speculate it wasn't quite tight enough when it left the Mother Ship.
I'd replace any gaskets, and snug it up properly.
For giggles, have a look at one of your other boxes. I think this is a one-off.
Chris.
 
Given that the distortion was somewhat level dependent, and did change somewhat when the cabinets were handled (we swapped the misbehaving cabinet from the inside of the array, where it covered the main audience area, to the outside of the array, where it was functioning more as a fill box), improper loading of the diaphragm is a plausible explanation. Assuming the diaphragm wasn't damaged by operation with a loose driver, I agree with Chris on likely root cause and remedy.
 
Kevin Maxwell said:
For Android I use this one https://play.google.com/store/apps/details?id=com.keuwl.functiongenerator
It even lets you setup a repeating sweep. It isn’t the easiest thing to use but it does a lot.

I also have one of these http://www.fullcompass.com/prod/070...MIz9iLw42u2wIVFCWBCh3pKgZnEAQYAiABEgLxZPD_BwE
It allows you to manually control the rate of the sweep and when you hear the problem you can zero in on it better.

Do you use the EV DX46 DSP with these speakers?
Click to expand...

I have a Sabine NAV480 with settings from EV/Telex. At their request I sent them the unit and they used it to establish settings from their reference unit.



 
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