Help with amplification/crossover/sub hum settings

[Altyros]

I have the following speaker setup: Martin Logan XTF200 (2), XTC100, XTB100 (4), Sistine 4XC (4), PSA EV1813 (2). Seems to be a 7.2.4 setup with the Sistines as ceiling speakers.

1) My question is I assume on my marantz cinema 40 I would set the amp assignment to 11 channels?

2) Next question is should I use my buckeye nc502mp 8 ch amp to power fronts-center-surrounds-rear surrounds or use the external Buckeye amp to power the fronts-center-ceiling speakers and plug rear surrounds into actual marantz?

3) Another question is should I set the crossover across the board to 80hz or individualize per speaker set?

4) Any idea on this one would be helpful, on my PSA1813s, there is an audible hum however the volume of the hum goes down when I turn the crossover knob on the subs down? Did I set a setting wrong or am I missing something? I am trying to get the best possible sound and response.

 

[lovinthehd]

1/ Sure
2/ I'd use them on the channels most needing extra power....so fronts then surrounds then other types of surrounds in that order....
3/ I'd start at 80 generally, and experiment above and below (ideally measuring to see what is best)....are you running Audyssey?
4/ I'd ask Tom why his sub hums like that (you sure its not a ground loop hum coming into play?)

 

[TLS Guy]

I have the following speaker setup: Martin Logan XTF200 (2), XTC100, XTB100 (4), Sistine 4XC (4), PSA EV1813 (2). Seems to be a 7.2.4 setup with the Sistines as ceiling speakers.

1) My question is I assume on my marantz cinema 40 I would set the amp assignment to 11 channels?

2) Next question is should I use my buckeye nc502mp 8 ch amp to power fronts-center-surrounds-rear surrounds or use the external Buckeye amp to power the fronts-center-ceiling speakers and plug rear surrounds into actual marantz?

3) Another question is should I set the crossover across the board to 80hz or individualize per speaker set?

4) Any idea on this one would be helpful, on my PSA1813s, there is an audible hum however the volume of the hum goes down when I turn the crossover knob on the subs down? Did I set a setting wrong or am I missing something? I am trying to get the best possible sound and response.

You can bet that hum is a ground loop. Do a test with a cheater plug on the sub, but don't leave it there. There has to be a difference in ground potential between what the sub is plugged into and the rest of your gear if the cheater plug is a temporary fix.

 

[PENG]

I have the following speaker setup: Martin Logan XTF200 (2), XTC100, XTB100 (4), Sistine 4XC (4), PSA EV1813 (2). Seems to be a 7.2.4 setup with the Sistines as ceiling speakers.

1) My question is I assume on my marantz cinema 40 I would set the amp assignment to 11 channels?

2) Next question is should I use my buckeye nc502mp 8 ch amp to power fronts-center-surrounds-rear surrounds or use the external Buckeye amp to power the fronts-center-ceiling speakers and plug rear surrounds into actual marantz?

3) Another question is should I set the crossover across the board to 80hz or individualize per speaker set?

4) Any idea on this one would be helpful, on my PSA1813s, there is an audible hum however the volume of the hum goes down when I turn the crossover knob on the subs down? Did I set a setting wrong or am I missing something? I am trying to get the best possible sound and response.

HD gave you the answers already, but I might add that if you don't want to run REW to help you see what's going on in your room, 80 Hz will most likely be the best for the XTF200. It has good extension down to 40 Hz, but again, 80 Hz will likely get you the smoothest response. You can also try 60 Hz and let your ears choose, though that is not a reliable way for various reasons.

That hum, as HD and TLS mentioned, is likely ground loop related. It may be an easy fix but may be not. You could also try a RCA to XLR cable and use the PSA's XLR input. There is a slim chance that it may help.
Here's a post with link to Hypex's documentation on the use of such cable:
Making my own RCA -> XLR cables | Audio Science Review (ASR) Forum

Again, there is a chance, but rca to xlr, even in the best case scenario is not going to get the full benefits of XLR to XLR but for $30 there is no harm trying:

Amazon.com: Monoprice XLR Male to RCA Male Cable - 1.5 Feet - Black, 16AWG Shielded Twisted Pair Oxygen-Free Copper Braid Conductors, E21 Gold Plated Connectors - Premier Series : Electronics

DC blocker may also work, but only if your issue is related to DC offset:

A DC Blocker to help stop transformer HUM | Audio Science Review (ASR) Forum

As HD suggested, give Tom a call.

Another possibility is that your Cinema 40 is the issue. I only mention this because many people experienced such hum a few years ago, iirc most had the issue with the AV7005, yet mine never had the issue.

Here's one example of such complaint:
Marantz AV7005 - serious ground loop hum | Audioholics Home Theater Forums

If yours is within the return/exchange window, you could easily swap it out with another and see if it makes a difference. At the minimum, you have 4 subouts, so try another one, it only takes a couple minutes to try it out.
That's a ton of work, so it should be your last resort, if none of the suggested solutions work. And before that, you probably should try it with another subwoofer first, borrow one if you can, that's just in case the PSA1018 is the issue.

 

[TLS Guy]

HD gave you the answers already, but I might add that if you don't want to run REW to help you see what's going on in your room, 80 Hz will most likely be the best for the XTF200. It has good extension down to 40 Hz, but again, 80 Hz will likely get you the smoothest response. You can also try 60 Hz and let your ears choose, though that is not a reliable way for various reasons.

That hum, as HD and TLS mentioned, is likely ground loop related. It may be an easy fix but may be not. You could also try a RCA to XLR cable and use the PSA's XLR input. There is a slim chance that it may help.
Here's a post with link to Hypex's documentation on the use of such cable:
Making my own RCA -> XLR cables | Audio Science Review (ASR) Forum

Again, there is a chance, but rca to xlr, even in the best case scenario is not going to get the full benefits of XLR to XLR but for $30 there is no harm trying:

Amazon.com: Monoprice XLR Male to RCA Male Cable - 1.5 Feet - Black, 16AWG Shielded Twisted Pair Oxygen-Free Copper Braid Conductors, E21 Gold Plated Connectors - Premier Series : Electronics

DC blocker may also work, but only if your issue is related to DC offset:

A DC Blocker to help stop transformer HUM | Audio Science Review (ASR) Forum

As HD suggested, give Tom a call.

Another possibility is that your Cinema 40 is the issue. I only mention this because many people experienced such hum a few years ago, iirc most had the issue with the AV7005, yet mine never had the issue.

Here's one example of such complaint:
Marantz AV7005 - serious ground loop hum | Audioholics Home Theater Forums

If yours is within the return/exchange window, you could easily swap it out with another and see if it makes a difference. At the minimum, you have 4 subouts, so try another one, it only takes a couple minutes to try it out.
That's a ton of work, so it should be your last resort, if none of the suggested solutions work. And before that, you probably should try it with another subwoofer first, borrow one if you can, that's just in case the PSA1018 is the issue.

I have always had to tightly bond the ground pin (the one for turntable grounding) to the AV rack with a robust cable, to keep it really quiet. That gets rid of the last trace of hum.