Faulty internal crossover?

[mossman77]

Could be but still would like to see multi measuring positions as well as possibly playing around with seat and or speaker position as well.....

That will really nail it down. You will also be able to find where this is occurring by measuring the preots and the speaker outputs. I assume you also have a signal generator as well, as that will also be required.

I'll be using REW's integrated signal generator. I started to take some measurements earlier with an old analog scope but it's all out of calibration and really belongs in the garbage.

 

[TLS Guy]

It just sounds you aren't familiar with settings and behavior....whether you need it with your super awesome speaker and room setup, who knows.

Well I don't need it.

FR of a main speaker at 2 meters.

FR at MLP

So there is a slight shelving of the HF as there should be at the listening position. The room has a slight null at 80 Hz, but not serious. The sub outputs come in at 40 Hz. So this is set as you can see that at 2 meters they are set a little low and there is some room gain below 30 Hz. By measurement and listening this sounds to be optimal. The bass sounds very well balanced. So yes,, it needs leaving alone and forgetting to enjoy the music, which is the object of it all.

 

[PENG]

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

Did you have the subwoofer "On"? Sorry but I have to ask.

 

[PENG]

Well I don't need it.

FR of a main speaker at 2 meters.

FR at MLP

So there is a slight shelving of the HF as there should be at the listening position. The room has a slight null at 80 Hz, but not serious. The sub outputs come in at 40 Hz. So this is set as you can see that at 2 meters they are set a little low and there is some room gain below 30 Hz. By measurement and listening this sounds to be optimal. The bass sounds very well balanced. So yes,, it needs leaving alone and forgetting to enjoy the music, which is the object of it all.

Can you show us the same plots without smoothing, for the 10-150 Hz, just for comparison with others like me and Pogre? Thanks

 

[mossman77]

Soft reset didn't help. Contacted Marantz for warranty service. O-scope won't arrive for two weeks, so it will be a while until I am able to take some measurements. In the meantime, could I feed the right channel preout to input 2 of my miniDSP, apply a HPF, then feed back into the receiver's audio in? Then I could reassign the inputs (I'd patch the left channel out directly to the left channel audio in).

 

[Pogre]

Hey, can you please describe again what it is that makes you think something is faulty? I haven't seen or heard anything that convinces me you even have a problem. I'm confused as to how you have deduced an issue. I mean, when you do a sweep with both speakers and subs you have a good response, right?

 

[mossman77]

Hey, can you please describe again what it is that makes you think something is faulty? I haven't seen or heard anything that convinces me you even have a problem. I'm confused as to how you deduced a problem.

The signal level of the right channel does not decrease below the xover frequency. It actually increases. For instance, an 80Hz tone plays louder than a 100 Hz tone, 63Hz louder than 80Hz, 50Hz same as 63Hz. Switching the right and left speaker cables at the receiver causes the problem to switch to the left speaker, so not room effects. Right channel output at 80 Hz is 12dB louder than the left channel, and 15dB louder at 63 Hz.

 

[Pogre]

The signal level of the right channel does not decrease below the xover frequency. It actually increases. For instance, an 80Hz tone plays louder than a 100 Hz tone, 63Hz louder than 80Hz, 50Hz louder than 63Hz. Switching the right and left speaker cables at the receiver causes the problem to switch to the left speaker.

Do you have Audyssey, DEQ, Graphic EQ... basically any and all sound enhancements turned off when you take the measurements? Mic positions, even a fraction of an inch makes a difference. Did you put the left speaker in the same spot the right speaker was when you switched the cables and compared?

Do you have a recent sweep with enhancements turned on, both subs and both speakers? What does the end result look like?

*Edit: A full sweep of each speaker individually, then together with subs might help us uncover something too.

 

[mossman77]

Do you have Audyssey, DEQ, Graphic EQ... basically any and all sound enhancements turned off when you take the measurements? Mic positions, even a fraction of an inch makes a difference. Did you put the left speaker in the same spot the right speaker was when you switched the cables and compared?

Do you have a recent sweep with enhancements turned on, both subs and both speakers? What does the end result look like?

Audyssey on or off doesn't make a difference, and the SPL levels I am getting front right speaker to left speaker when swapping receiver outputs varies by only 1dB or so. Just the fact that the right channel output does not start dropping off until I get down to 50Hz regardless of what I set the receiver xover to (I tried 90, 100, 120, 150) tells me something is wrong. The left channel drops off as expected. I get the exact behavior and SPL values (+/- 1dB) when swapping receiver outputs. IOW, the issue doesn't follow the speaker, it follows the receiver.

 

[Pogre]

Sounds like room mode to me. I edited above too. Some full sweeps (well, 20-200) would be helpful. Individually, together, subs, no subs Audyssey on and off.

 

[mossman77]

Sounds like room mode to me. I edited above too. Some full sweeps would be helpful. Individually, together, subs, no subs Audyssey on and off.

Subs are off. I took sweeps with and without Audyssey and no change in odd behavior. I posted plots of the left channel vs right. Issue changes to left speaker when I swap cables at the receiver. If it was the room, then the issue wouldn't flip from one speaker to the other. It would stay with the speaker, right?

 

[mossman77]

Front left and front right response curves are shown in post#18. The blue curve is the right channel. Notice the signal increases significantly below the xover frequency. I see the same behavior when doing single tone measurements (see dB levels I posted).

The overall system response looks great, but the sub response conceals the issue with the front right channel.

 

[lovinthehd]

So no full reset yet? That's probably what warranty service will have you do....

 

[mossman77]

So no full reset yet? That's probably what warranty service will have you do....

Not yet. I'll do that now. Standby.

 

[lovinthehd]

Also how about the details of your measurement positions etc?

 

[Pogre]

Also how about the details of your measurement positions etc?

Yes! More details. I'm still unconvinced, lol.

 

[mossman77]

Also how about the details of your measurement positions etc?

I'm using a single measurement point. I don't see the point in moving the mic around when flipping left/right channels only makes 1dB of difference. The left channel and left speaker behaves as expected (signal drops off below xover point), the right channel does not drop off and actually increases, and is 14dB louder. When I switch the left and right CABLES at the receiver, the behavior switches to the left speaker and I get the exact same behavior as I did with the right speaker, which tells me it is not the room. I am not moving the mic or speakers. I am only swapping cables at the receiver output.

 

[Pogre]

Front left and front right response curves are shown in post#18. The blue curve is the right channel. Notice the signal increases significantly below the xover frequency. I see the same behavior when doing single tone measurements (see dB levels I posted).

The overall system response looks great, but the sub response conceals the issue with the front right channel.

The signal increase is not necessarily indicative of any kind of issue. It could be a peak caused by a room mode or something Audyssey did intentionally to compensate for a null elsewhere. My right speaker by itself is a complete measurable mess before and after running Audyssey, but when everything is playing together it all sums. It sounds and measures fantastic.

 

[mossman77]

The signal increase is not necessarily indicative of any kind of issue. It could be a peak caused by a room mode or something Audyssey did intentionally to compensate for a null elsewhere. My right speaker by itself is a complete measurable mess before and after running Audyssey, but when everything is playing together it sounds and measures fantastic.

I understand what you're saying, but Audyssey is off and the issue flips to the left channel when I swap cables. I posted the Audyssey correction curves a few posts back. Wouldn't I see a huge boost below 80Hz in the Audyssey curve if that was the case? 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.

 

[lovinthehd]

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