High distortion on a speaker

[kalhimeo]

Hi,

I am a beginner with REW and I am sorry if this question sounds stupid I recently started with speaker measurements in order to use Audyssey One scripts, and I noticed that one of my Atmos speakers shows unusual distortion between 1kHz and 8kHz (I get the same curve on every measurement so it's not related to temporarily room noise or such external factor). I have 4 similar ELAC IC-DT61-W in-ceiling top speakers and only that one has this distortion curve, all others have normal curves (all measurement taken in the same conditions). These measurements were made with an umik-1 with calibration file, atmos sweeps with time reference, on a Denon x3800h with normal speaker outputs for 2 speakers, and pre-amp with Fosi Audio TDA7498E for the 2 others including the speaker with the distortion problem.

I was wondering what can cause this ? Can it be a defective speaker ? Wiring ? External Amp problem ? Speaker improperly attached into the recessed ceiling, like vibration ? External factor in the room ? I am also wondering what are the consequences of this higher distortion for the calibration and/or the listening experience ?

First image with 3 measurements of that 'problematic' speaker distortion :

The other atmos speakers with normal curves (3 measurements per speaker), note that the one with higher distortion bellow 200hz is the other speaker on the pre-out.

The SPL curve for the 'problematic' speaker (one of the measurements) :

Any clue would be much appreciated. Thank you very much !

 

[staticV3]

Hi @kalhimeo! Welcome to ASR.

Wiring or external room factors are unlikely to cause this.

You can rule out the Amp by temporarily connecting the troublesome speaker to the same Amp output that gave clean results with your other Atmos speaker.

In the end, the most likely culprits are a faulty speaker or faulty installation.

 

[DVDdoug]

And... Try connecting it to a "regular stereo" channel so you're not relying on Atmos. It should be obvious is one of the "identical" speakers has a problem and if it sounds different from the other with the same connection..

I'm guessing it's the speaker. It's unlikely to be "vibration" at those frequencies.

You didn't actually say you're hearing any distortion or anything wrong.

 

[kalhimeo]

Thank you very much for your feedback. I can confirm that it's coming from the speaker itself. I still had the problem after inverting the amp outputs, therefore I took the atmos speaker out of the ceiling and connected it directly to the Denon on a different speaker output which was showing no distortion: the result is that the atmos speaker shows the same distortion ou that other output, so the problem lies with the speaker itself.
To be honest I never noticed anything wrong because it's "only" a top rear atmos, so it's not playing that often. I am not an audio specialist at all so I don't even know what would be the audible consequence of this measured distortion or what to try to hear. Also it's only above 1000Hz.

Do you think that can have an audible impact and worths RMA ? (I realize that it's probably difficult for you to judge without hearing it )