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Discussion Starter · #1 ·
Hey everyone, I'm having an issue with my midranges and I need some extra brains on the case.
I'm getting distortion from an unknown source through my midranges at any volume. It scales with the music being played. Most noticable with instruments like pianos and guitars when playing alone. It's easily masked with other instruments, but it is still very noticable on many songs. Sort of sounds like clipping, but it is still noticable until it becomes too quiet to hear and at that point the song is also nearly too quiet to hear as well. The strange part is that the distortion is only in the higher octaves that the speaker is playing.

All of my gains are set very conservativly, and I have more power on tap than I can use before my ears would bleed. My gains are set to use my volume up to 3/4 on the headunit. I am only using +3db eq in the helix, but had the issue with previous tune using no boosts. Music is coming from Android auto and tidal.

  1. So far I have checked for distortion in the songs using headphones and my home system, so that is ruled out.
  2. I've moved my crossovers up while listening to see if it due to playing them too low. Did nothing until the crossover was set at 2.5k when it began to disappear.
  3. I've swept a high cut eq band through the entire range to see if it was clipping from too much power anywhere. Didn't help.
  4. Made the baffle more sturdy and sealed everything with butyl to make sure it wasn't a leak. No change.
Has anyone else had a similar issue? The only things I can think of are that the opamp for the helix channels used (c&d) is going bad perhaps? Or that channels 3&4 of my mosconi zero 4 is doing something strange to the signal? It just seems very strange that it only is effecting those 2 drivers and only a very narrow range of frequencies and I have no idea what could even cause that.
If anyone has any ideas, I would love to hear them even if they are spitballing. Thanks guys!
 

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Discussion Starter · #2 ·
I'll post up an audio clip tomorrow so everyone can get a gauge on the issue. This has been driving me mad for months now lol. Also going to try to move around amp channels and dsp channels to see if that makes a difference.
I also forgot to mention that it is there with cds, AA, and aux as well.
 

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Also going to try to move around amp channels and dsp channels to see if that makes a difference.
Yes this is the easiest place to start ... though perhaps first you might want to check tightness of connections and/or simply swap RCA interconnects that are driving the midrange channels just to eliminate that as a possibilty as well.
 

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Discussion Starter · #4 ·
Yes this is the easiest place to start ... though perhaps first you might want to check tightness of connections and/or simply swap RCA interconnects that are driving the midrange channels just to eliminate that as a possibilty as well.
Would something like a loose RCA cause noise in a narrow bandwidth? Ive been able to rule out the amp channels and am working on switching RCAs/dsp channels now.
If this doesn't fix something I am at a loss
 

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^^^ assuming that you have a pair of RCAs interconnects that feed the midrange signal from the source to the DSP and then from the DSP to the amp it is certainly possible.

If, on the other hand, you are feeding a full range signal from the source to the DSP which is also the amplifier, then my suggestion is no longer likely or even plausible.
 

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Maybe just use a tone generator, and see if it is a mechanical resonance?
 
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Hey everyone, I'm having an issue with my midranges and I need some extra brains on the case.
I'm getting distortion from an unknown source through my midranges at any volume. It scales with the music being played. Most noticable with instruments like pianos and guitars when playing alone. It's easily masked with other instruments, but it is still very noticable on many songs. Sort of sounds like clipping, but it is still noticable until it becomes too quiet to hear and at that point the song is also nearly too quiet to hear as well. The strange part is that the distortion is only in the higher octaves that the speaker is playing.

All of my gains are set very conservativly, and I have more power on tap than I can use before my ears would bleed. My gains are set to use my volume up to 3/4 on the headunit. I am only using +3db eq in the helix, but had the issue with previous tune using no boosts. Music is coming from Android auto and tidal.

  1. So far I have checked for distortion in the songs using headphones and my home system, so that is ruled out.
  2. I've moved my crossovers up while listening to see if it due to playing them too low. Did nothing until the crossover was set at 2.5k when it began to disappear.
  3. I've swept a high cut eq band through the entire range to see if it was clipping from too much power anywhere. Didn't help.
  4. Made the baffle more sturdy and sealed everything with butyl to make sure it wasn't a leak. No change.
Has anyone else had a similar issue? The only things I can think of are that the opamp for the helix channels used (c&d) is going bad perhaps? Or that channels 3&4 of my mosconi zero 4 is doing something strange to the signal? It just seems very strange that it only is effecting those 2 drivers and only a very narrow range of frequencies and I have no idea what could even cause that.
If anyone has any ideas, I would love to hear them even if they are spitballing. Thanks guys!
I think you've already ruled it out, but maybe you have digital clipping. If you have disabled all eq, then I guess that's not possible. I just felt the need to throw that out there.
 
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Digital clipping should also show up in tweeters,..
 

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Discussion Starter · #9 ·
I think you've already ruled it out, but maybe you have digital clipping. If you have disabled all eq, then I guess that's not possible. I just felt the need to throw that out there.
I thought my op was getting a bit lengthy so I left out a few things.
I tried my best to check for digital clipping. I made sure that I kept my 6v output headunit below 3/4 because the helix only takes a 4v input. I also went through to make sure that the input voltage gain on the helix was set to the minimum gain @4v on every one of the inputs. All of the EQ on the heaunit is set at 0, also all sound effects off. Unfortunatly AA won't let you change the output volume on the phone which is somewhat annoying.
As far as digital clipping goes, idk what else to check for.
 

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Discussion Starter · #10 ·
Maybe just use a tone generator, and see if it is a mechanical resonance?
Unfortunately it comes through when being played free-air as well. I actually thought it was my drivers themselves for the longest time, so I upgraded and it's still there. So it has to be within the signal path somewhere.

Haven't had the chance to check a couple unused dap channels yet. But I got everything all setup today, so I can find out for sure tomorrow.
 

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Also sometimes a nicked speaker wire that is grounding out can do this, though if it is doing it through BOTH midranges, that is more unlikely .
 

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Discussion Starter · #12 ·
Also sometimes a nicked speaker wire that is grounding out can do this, though if it is doing it through BOTH midranges, that is more unlikely .
Good to know. If thus dsp channel/rca switch doesn't do anything I will run a test wire. I think it happens to the passengers side just as much, but it is had to tell. It becomes less noticable the further off axis you are.
I'm gonna run a tone generator through it and see what frequencies excite it and if it's the same as with the old speakers. I believe it was around 2-2.5khz with the most noticable being at 2250
 

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I have the same issue! And like you I have tried everything for months. I stream thru tidal and Deezer to a topping d10 then optical into my helix.
I have swapped all wires and all speakers and amps. Even tried a friends helix. I’ve compared same tracks from tidal and Deezer and no changes. But did find that Deezer usually sounds better as in the center soundstage is tighter by A lot on some songs. And I have tidal masters and Deezer Hifi. I have a thread about my issue also. Some days it seems like it’s not to noticeable then other days it drives me insane …. Please post a clip of the sound! I sometimes think maybe my iPhone is the cause but need another source to try and compare them
 

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Discussion Starter · #14 ·
I have the same issue! And like you I have tried everything for months. I stream thru tidal and Deezer to a topping d10 then optical into my helix.
I have swapped all wires and all speakers and amps. Even tried a friends helix. I’ve compared same tracks from tidal and Deezer and no changes. But did find that Deezer usually sounds better as in the center soundstage is tighter by A lot on some songs. And I have tidal masters and Deezer Hifi. I have a thread about my issue also. Some days it seems like it’s not to noticeable then other days it drives me insane …. Please post a clip of the sound! I sometimes think maybe my iPhone is the cause but need another source to try and compare them
I was trying to earlier. But kept running into the issue of not being able to record and play music at the same time lol. I have VERY few cds so finding a track that does it noticably is difficult.
I did try and turn off absolute bluetooth volume at one point in an attempt to circumvent not being able to control Bluetooth output volume in Android auto, but it didn't help either.

I got the blessing to nab the lady's phone tomorrow to record though. So I'll be sure to ping you when I get to post it!
 

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Unfortunately it comes through when being played free-air as well. I actually thought it was my drivers themselves for the longest time, so I upgraded and it's still there. So it has to be within the signal path somewhere.

Haven't had the chance to check a couple unused dap channels yet. But I got everything all setup today, so I can find out for sure tomorrow.
Maybe put ear pods in and run the RCAs that feed the MR amps into those ear buds?

If that is fine then a speaker or “cabinet resonance” seems likely.
 

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I was trying to earlier. But kept running into the issue of not being able to record and play music at the same time lol. I have VERY few cds so finding a track that does it noticably is difficult.
I did try and turn off absolute bluetooth volume at one point in an attempt to circumvent not being able to control Bluetooth output volume in Android auto, but it didn't help either.

I got the blessing to nab the lady's phone tomorrow to record though. So I'll be sure to ping you when I get to post it!
lol that’s the same problem I had. I can’t record the noise because I’m using my phone to play the damn noise 😂😂. Have you check all your phone audio settings?
 

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Discussion Starter · #18 ·
lol that’s the same problem I had. I can’t record the noise because I’m using my phone to play the damn noise 😂😂. Have you check all your phone audio settings?
Yeah I've dug into all of the eq options that the phone has with nothing being set from neutral.
 

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Yup. Yoi can buy them for couple dollars on Amazon
But yoi need good ear buds most likely to hear the noises. Sometimes I feel like I can hear the same noises when I use my speaker phone to play the music. I need another phone to compare mine too
 
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