One speaker clipping (Neumann KH 80) seemingly much earlier than the other

[nat1]

For clarity my full setup is:

Neumann KH 80 pair
Minidsp 2x4: The maximum output of the non HD version is 0.9vrms and it's connected straight into my PC's onboard audio so I have to run the KH 80's at 0db input gain and 108dB output level on the back controls to get a reasonable volume.
BK XLS200 Subwoofer
Source is my PCs onboard audio
Listening distance is around 0.5m - 0.75m, on a desk

I've had my Neumann KH 80's for a while but today was the first time playing them what I'd call loud/semi loud. I was playing some songs and I managed to get one of them (my left speaker) to flash red multiple times which indicates clipping, although I will note I didn't hear any bad/odd sounds. This was quite surprising to me as they are crossed over to a subwoofer (BK XLS200) at 120hz. I looked at the woofers while they were playing with my phone light through the grills, and they were barely moving so it for sure wasn't due to overexcursion. Since it was only happening to one speaker I decided to mute the left channel and see if I could replicate the same thing on the right speaker. At the same volume, I couldn't get it to light up red, and even when I raised the volume beyond what my left speaker was playing it didn't flash red once. So it seems like one of my speakers has the limiters set a decent amount lower than the other?

 

[DVDdoug]

There could be something wrong with the speaker and maybe it's just something wrong with the clipping indicator. (You probably won't hear distortion with slight clipping.)

I would repeat the experiment with a mono file.

 

[nat1]

That's a good idea to try it in mono, I'll see if I can get that done tomorrow at an appropriate time as I need some volume to produce the clipping. Although part of me doesn't want to keep trying to clip it on purpose anymore, in fear of damaging it.

 

[jhaider]

Can you try it with a higher output source?

 

[LTig]

Flip the speakers and check if the problem follows the speaker.

 

[wwenze]

Maybe bad power supply rails? One way to check for bad 60Hz capacitor (yes even in SMPS there is a 60Hz capacitor) is to play a 1.2kHz sine wave and see whether the waveform clips once every 10 cycles.

And like #2, it could be just the indicator. Although I would guess that the indicator and the compression circuitry are controlled by the same signal.

In any case, a mic will tell you whether both speakers have the same clipping behavior. A mic can also quantify the difference in clipping point i.e. how many dB difference between the two speakers. 1dB difference would be acceptable, 6dB or 10dB would be defective.