Faulty internal crossover?

[mossman77]

Expand on your reasoning about a single mic position as to how useful that really is....

Because I'm not characterizing or correcting for room effects. I'm doing a comparative analysis of the receiver's left and right channels. I realize there will be differences between the left and right response, but in the range I am analyzing, there is only a 1dB or so difference.

Did I make it clear that I am measuring a single speaker at a time?

 

[Pogre]

And an 80Hz filter is an 80Hz filter. Regardless of what Audssey does, the signal should roll off at 12dB/octave below the xover point. It does not.

And unless you're in the perfect room with the perfect setup and acoustics it's likely never going to roll of at exactly 12 dB per octave. That's just how it goes sometimes. Room modes or reflections will amplify certain frequencies. This is why HD is asking about your measuring technique. You might move that mic a foot to the left and that peak in frequency could get worse, disappear or even go the other direction.

I wish I could teleport to your place and dig in with you man. I know it's frustrating. We're not just busting your balls tho. Just trying to zero in on it.

 

[mossman77]

And unless you're in the perfect room with the perfect setup and acoustics it's likely never going to roll of at exactly 12 dB per octave. That's just how it goes sometimes. Room modes or reflections will amplify certain frequencies. This is why HD is asking about your measuring technique. You might move that mic a foot to the left and that peak in frequency could get worse, disappear or even go the other direction.

Right, I understand. I was using theoretical numbers. I just meant the left channel rolls off but the right does not.

 

[Pogre]

Right, I understand. I was using theoretical numbers. I just meant the left channel rolls off but the right does not.

You're quoting me too fast! lol.

I edited another line into my reply above.

 

[mossman77]

Lets say you were to place a mic directly in front of a speaker, take a measurement from 50Hz to 100Hz, notice the signal begin to decrease around 100Hz, increase substantially at 80Hz, flat down to 63 Hz, and it began dropping off at 50Hz. Then you swapped the cables on the back of the receiver and did an second sweep, but then got a normal response (signal steadily decreasing down to and below the xover point). It should immediately become evident that the receiver is the cause.

 

[mossman77]

And unless you're in the perfect room with the perfect setup and acoustics it's likely never going to roll of at exactly 12 dB per octave. That's just how it goes sometimes. Room modes or reflections will amplify certain frequencies. This is why HD is asking about your measuring technique. You might move that mic a foot to the left and that peak in frequency could get worse, disappear or even go the other direction.

I wish I could teleport to your place and dig in with you man. I know it's frustrating. We're not just busting your balls tho. Just trying to zero in on it.

Right, but I am not changing the mic location. Only swapping the speaker cables. Right channel response increases below 80 Hz and only drops around 50 Hz, plug right cable into left output and issue vanishes from right speaker and occurs on left channel.

 

[Pogre]

Right, but I am not changing the mic location. Only swapping the speaker cables. Right channel response increases below 80 Hz and only drops around 50 Hz, plug right cable into left output and issue vanishes from right speaker and occurs on left channel.

You're not moving the mic, but you are moving where the signal is coming from, right?

 

[mossman77]

I'm going to do a master reset to see if that fixes it. I don't expect it will. My new o-scope will hopefully be here next week and that will allow me identify the issue without a doubt, because I will be measuring voltage, not SPL, so the speaker and room will be inconsequential.

 

[mossman77]

You're not moving the mic, but you are moving where the signal is coming from, right?

Correct. Nothing is moving. Simply taking the speaker cable from the right speaker and plugging it into the left output and taking left and plugging it into the right output. Whichever speaker is connected to the receiver's right channel exhibits the odd behavior.

 

[Pogre]

I'm going to do a master reset to see if that fixes it. I don't expect it will. My new o-scope will hopefully be here next week and that will allow me identify the issue without a doubt, because I will be measuring voltage, not SPL, so the speaker and room will be inconsequential.

Right on. I hope I'm right and you don't have any major issues, but I don't discount it either. *crossing fingers*

 

[Pogre]

Correct. Nothing is moving. Simply taking the speaker cable from the right speaker and plugging it into the left output and taking left and plugging it into the right output. Whichever speaker is connected to the receiver's right channel exhibits the odd behavior.

Yeah, that's the thing tho. You're not moving the mic, but when you switch speakers it's the same effect, unless you're physically moving the speaker too.

 

[mossman77]

Yeah, that's the thing tho. You're not moving the mic, but when you switch speakers it's the same effect, unless you're physically moving the speaker too.

No, because I measure the same speaker after swapping the cables and the response I completely changes (signal increases below cutoff).
I did a master reset and am getting some more curves now. Issue still persists.

 

[lovinthehd]

Maybe it is simply defective but humor us with more mic positions?

 

[mossman77]

F!

 

[PENG]

No, because I measure the same speaker after swapping the cables and the response I completely changes (signal increases below cutoff).
I did a master reset and am getting some more curves now. Issue still persists.

If the same thing happened to the left speaker after swapping the feeds then yes there is something wrong with the receiver.

You said Audyssey was off, that's good, keep it that way. You also said sub was off, but I hope you switched it off or pulled the plug just to be sure.

While waiting for the meter, try pure direct too and see what happens.

Can also try use using the center or surround channel to feed the right speaker, again just to further proof there is something wrong with the front right channel. I think you proved it already but I would prove it twice, that's just me..

 

[lovinthehd]

F!

Okay okay

 

[mossman77]

Let me preface with, if I were seeing the behavior as I described, the receiver would certainly be the cause, but....

Apparently I confused the L and R output in REW with the L and R output on the receiver and which speaker was playing for a given sweep (I was seated well to the side of the LP and didn't verify which speaker was actually playing). So...my apologies. I was mistaken. I'm a dummy. A smart dummy though because I would have been right if I knew my right from my left. Lol.

...it's the room (face palm).

So, now that has been solved, evidently Audyssey can't correct it, so I guess I just accept it and appreciate the free additional bass response I am getting from the right speaker. Lol.

 

[Pogre]

Let me preface with, if I were seeing the behavior as I described, the receiver would certainly be the cause, but....

Apparently I confused the L and R output in REW with the L and R output on the receiver and which speaker was playing for a given sweep (I was seated well to the side of the LP and didn't verify which speaker was actually playing). So...my apologies. I was mistaken. I'm a dummy. A smart dummy though because I would have been right if I knew my right from my left. Lol.

...it's the room (face palm).

So, now that has been solved, evidently Audyssey can't correct it, so I guess I just accept it and appreciate the free additional bass response I am getting from the right speaker. Lol.

It's all good man. I go through the same shit from time to time. Glad you figured it out and put it to rest.

 

[mossman77]

It's all good man. I go through the same shit from time to time. Glad you figured it out and put it to rest.

Thanks man. I appreciate that.

 

[lovinthehd]

It's always good to double check everything or look at things from different angles.....