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Had someone from Focal tech dept told me to check the 4 - 5khz, the 1khz, and the 200-250hz ranges cause I keep blowing speakers. When I did I found distortion in the 4khz range when volume hit 13 & it goes to 40 but only distorts at 36/40hz & 39/1khz so I'm wondering if it's in HU or DD-1. Tried it on two different HU's. A Pioneer mvh-2300nex & an Alpine iLX-W650 

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So I was taking a look at the DD-1+ and it has a "Quasi-RMS voltmeter (can detect clipping at any frequency)" feature that sounds like should work.

 

DD-1+:

https://www.wccaraudio.com/smd-distortion-detector-plus-dd-1.html

 

I don't see that feature listed on the original DD-1:

https://www.wccaraudio.com/smd-distortion-detector-dd-36.html

 

Which one are you using to test for distortion?  Also, how many db of overlap do you have the amp tuned to and/or is there a mismatch in db recording level between your 4khz test tone track and where you tuned the amp to?

 

I think the original DD-1 manual refers to overlap tracks as "Sound Quality, Max volume, mixed" or something like that.  So if you tuned the amp using the "Max volume" track you are already going to be on the ragged edge of distortion and if your 4khz test track is boosted by say +3db, it could easily push you into distortion/clipping.

 

Also, what amps are driving the front stage?  Are they class D amps?  A lot (not all) of class D amps loose fidelity at higher frequencies, especially when they are getting towards to top of their output rating.

 

 

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I am using the regular DD-1. I was running an Alpine X-series class D amp. I just went to a Pioneer class FD to see if my Alpine amp was bad and still seen distortion in the 4khz -10db frequency at low volumes. Wasn't sure if DD-1 was accurate at 4khz so I set everything with the normal 1khz -10db & even turned it down a little trying not to blow anything and it still sounds bad. I can hear the distortion, guessing at aprox some where in that frequency range so that's what made me ask about the DD-1. I'm even setting gains with HU at 30 when it doesn't clip at 40hz or 1khz till 38 & 39. I've been fighting this thing for a long time now. Replaced the HU twice, multiple sets of speakers from JBL, Pioneer, Alpine, & Now Memphis Audio MJP6. Started running active before changing the amps & still blew my brand new X-series components & coaxials. And I really think it's the distortion slowly taking the speakers out lol.

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By distortion, what do you mean exactly? Is it staticy? Is it a hum? A high pitched wine? Does it sound like the speakers are being pushed past their mechanical limits? 

2011 Chevy Silverado under construction

My build log here. Check it out! 

 

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It's hard to explain, it's like a crackily static lol if that makes any sense. I'm pretty sure it's in the 2 - 8 khz range cause lowering EQ adjustments in that range & cutting that range out with the crossovers helps but as it takes away some that the overall starts sounding bad.

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My advice would be to start eliminating possible culprits. Make sure your HU settings are set to flat. No boosts of any kind, EQ set to flat. Male sure the crossover settings on the amplifier are set correctly as well. 

Are you using your phone to generate the test tones? If so, try it with a cd and see if you hear it. If your using the cd, try it with your phone. 

Try taking the HU completely out of the picture. Get an RCA to whatever jack you need for your phone or MP3 player or whatever you have and play directly into the amplifier (you might have to readjust your gain on your amp to match the phone so you don't end up with a false test).

It sounds like you already verified it wasn't the amp. 

Also, you can wiggle your wires and see if you can reproduce that sound on purpose. I've had that sound come through my speakers before and it was a loose connection into my ipod. 

Another problem that can be occurring is your speaker might not be flat. I assume it's in your doors? If that surface isn't perfectly flat, it can warp the core l cone and cause problems. To test this you can take the speaker out of wherever it's mounted and test it free air. Check each speaker individually because it could just be one speaker doing it out of the bunch. 

That's just a couple things. I hope it helps

Edited by Dafaseles

2011 Chevy Silverado under construction

My build log here. Check it out! 

 

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