Faulty internal crossover?

[mossman77]

I was taking some individual FR measurements on my front channel speakers last night and noticed the response of the right channel actually increased below the crossover point (after rolling off first). It basically did a u-turn. I then took some individual tone measurements and sure enough, the SPL of the right speaker increased below 80Hz before dropping off around 50Hz. I flipped the left/right channels and the issue switched to the left channel, which confirms it is the receiver. The speaker levels in the menu are exactly the same and Audyssey is off. Does it sound like I have a faulty internal crossover? This was a factory refurb unit, by the way. Here are the numbers I received at a few frequencies at and below the 80 Hz xover frequency:

100 Hz, left = 71dB, right = 52 dB
80 Hz, left = 58 dB, right = 70 dB
63 Hz, left = 56 dB, right = 71 dB
50 Hz, left = inaudible, right = inaudible

 

[WaynePflughaupt]

The issue is most likely room modes or asymmetrical placement (i.e. one speaker near a wall or an opening). The fact that you switched lines at the amp and nothing changed confirms it. If you want to see if it’s the speaker, move the suspect one to where the “good” one is and take new readings.

Regards,
Wayne A. Pflughaupt

 

[TLS Guy]

I was taking some individual FR measurements on my front channel speakers last night and noticed the response of the right channel actually increased below the crossover point (after rolling off first). It basically did a u-turn. I then took some individual tone measurements and sure enough, the SPL of the right speaker increased below 80Hz before dropping off around 50Hz. I flipped the left/right channels and the issue switched to the left channel, which confirms it is the receiver. The speaker levels in the menu are exactly the same and Audyssey is off. Does it sound like I have a faulty internal crossover? This was a factory refurb unit, by the way. Here are the numbers I received at a few frequencies at and below the 80 Hz xover frequency:

100 Hz, left = 71dB, right = 52 dB
80 Hz, left = 58 dB, right = 70 dB
63 Hz, left = 56 dB, right = 71 dB
50 Hz, left = inaudible, right = inaudible

That is a really strange fault.

The first thing to do is to check that the equalizer has not got activated.

If you can be certain the equalizer on that channel is not activated, then run FRs with the speakers set to large. That will help isolate it to the crossover or amp circuit.

Once you know that then do a factory reset if it is not the equalizer activated.

If it persists after a factory reset, then the unit is faulty and you probably have fond out why it was returned in the first place.

A 15 db increase at 63 Hz is very likely to cause speaker damage, so be careful.

 

[TLS Guy]

The issue is most likely room modes or asymmetrical placement (i.e. one speaker near a wall or an opening). The fact that you switched lines at the amp and nothing changed confirms it. If you want to see if it’s the speaker, move the suspect one to where the “good” one is and take new readings.

Regards,
Wayne A. Pflughaupt

The fault moves with the amp, not the speaker. This is the receiver.

 

[mossman77]

The fault moves with the amp, not the speaker. This is the receiver.

Correct. The right channel of the receiver is behaving the same regardless of which speaker is connected. It is not speaker or room dependent.

 

[WaynePflughaupt]

The fault moves with the amp, not the speaker. This is the receiver.

That’s not the way I read it. He didn't say he physically switched the speakers from one side to the other. If he merely switched the lines, then the speaker on the right side is now getting the left signal. He said the problem “moved” to the left, but the left channel is now the right speaker.

Sticking with my original assessment until the OP clarifies.

Regards,
Wayne A. Pflughaupt

 

[TLS Guy]

Correct. The right channel of the receiver is behaving the same regardless of which speaker is connected. It is not speaker or room dependent.

That is the way I understood your post. Thanks for clarifying. This is a strange fault that we have never had before. Unless the equalizer is turned on somehow or a reset solves it, that receiver will have to go back for service.

 

[mossman77]

That’s not the way I read it. He didn't say he physically switched the speakers from one side to the other. If he merely switched the lines, then the speaker on the right side is now getting the left signal. He said the problem “moved” to the left, but the left channel is now the right speaker.

Sticking with my original assessment until the OP clarifies.

Regards,
Wayne A. Pflughaupt

I apologize if I wasn't clear. I swapped the speaker lines at the back of the receiver and the issue changed from the right speaker to the left speaker, which indicates the right receiver channel is the issue.

 

[mossman77]

That is the way I understood your post. Thanks for clarifying. This is a strange fault that we have never had before. Unless the equalizer is turned on somehow or a reset solves it, that receiver will have to go back for service.

I ensured Dynamic EQ was turned off in the menu. I took a measurement with Dynamic EQ on as well and still had the same problem. I'd rather not do a master reset if I can help it. I've done a lot of measurements and incorporated an external DSP into the mix for my subs and everything is integrated very well right now. I suppose I may not have much of an option. I'm assuming a master reset will erase my Audyssey calibration? Is there a way to save the calibration and load it back in after? I guess it doesn't make a difference. I'm going to have to redo the calibration either way.

 

[WaynePflughaupt]

Is there any way to check EQ settings per-channel, like TLS suggested?

Regards,
Wayne A. Pflughaupt

 

[mossman77]

Is there any way to check EQ settings per-channel, like TLS suggested?

Regards,
Wayne A. Pflughaupt

I can access the user-adjustable graphic EQ if I turn Audyssey MultiEQ XT off and see/adjust an EQ for each individual channel, but the left and right are set identically. And there is no boosting applied to anything. However, I don't know if the settings shown are from what Audyssey did or default values. I'm guessing default because left and right are identical.

I was mistakenly turning on/off Dynamic EQ, not MultiXT as I thought, so I'll have to retake some measurements to see if this changes anything.

 

[WaynePflughaupt]

Judging from your opening post, it almost sounds like one channel isn't getting high-passed. But I don't think that's a possibility, as far as available settings go. Looks like it's time to get a new one.

Regards,
Wayne A. Pflughaupt

 

[mossman77]

Is there any way to check EQ settings per-channel, like TLS suggested?

Regards,
Wayne A. Pflughaupt

It didn't occur to me that was an option....here is what Audyssey did, which shows a few dB of boost around the 80Hz cutoff, but it actually boosted the left channel more, and what I am actually hearing isn't agreeing with these plots. Seems like a hardware issue (i.e. the crossover network).

 

[mossman77]

Side question....why is Audyssey doing any EQ'ing below 80Hz if it knows beforehand that the speakers are small (per the first room correction measurement point)?

 

[ryanosaur]

Your speakers are still outputting below crossover. I think its been said most AVRs apply a second order/12dB slope. So crossing at 80Hz for example, will still leave you with output below 40 Hz: it will be down 12dB in out put at that point, but the XO is NOT a hard cut off.

 

[mossman77]

Your speakers are still outputting below crossover. I think its been said most AVRs apply a second order/12dB slope. So crossing at 80Hz for example, will still leave you with output below 40 Hz: it will be down 12dB in out put at that point, but the XO is NOT a hard cut off.

Right, I realize that, but it is not 3dB down at 80 Hz and goes up below 80Hz before rolling back off. Something isn't right.

 

[TLS Guy]

Right, I realize that, but it is not 3dB down at 80 Hz and goes up below 80Hz before rolling back off. Something isn't right.

Just switch off Audyssey. Make sure everything Audyssey is totally disconnected. It is a horrid program that wants to constantly reinsert itself, if you don't put the settings lock on. So check your settings and make sure everything Audyssey is OFF and then put the setting lock on right away, otherwise it will bite you on the you know where. Audyssey is a horrid ghastly program that has no business being on any piece of audio equipment with any pretensions to quality.

 

[mossman77]

Setting lock?

Here are FR plots of the left and right channels. Notice the right channel (blue) rises again below the cutoff.

 

[TLS Guy]

Setting lock?

Here are FR plots of the left and right channels. Notice the right channel (blue) rises again below the cutoff.

View attachment 35428

What receiver do you have? Any pre/pro or receiver I'm familiar with has a setting in the set up menu to lock the settings so they don't accidentally get changed. Then you release the lock if you want to change a setting and relock it afterwards. If you forget, then you can bet Audyssey will do something dumb because it was written by some sort of Nazi, that insisted "you will conform and use Audyssey".

 

[mossman77]

Ran some tones again making sure MultiXT was off this time. No change whatsoever. Right channel still playing at 52dB at 100Hz, 70dB at 80Hz, and 72 dB at 63 Hz. Left channel rolls off as expected.