OB SUBS FINALLY WITH SPATIAL M3

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NoahH

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #160 on: 27 Oct 2022, 02:29 am »
Sorry guys, I've been totally covered up with work lately and haven't had much free time. I'm pretty much done trying to get this amp/sub/Dirac combination figured out. I would like to maybe keep them if I can implement one of Brian's class D 600watt amps. I'm in the middle of correspondence with him now regarding that. If he can pull it off, I will consider going that route. I know it sounds crazy, but that's just what I feel this sub needs if Dirac is going to be used. I love the fact of having loads of headroom when driving any speaker and think for ME, this pairing comes up a bit shy. Just my experience and two cents.

Vince

Did you ever try the speaker level inputs? What were the results with that?

77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #161 on: 27 Oct 2022, 03:01 am »
Sorry guys, I've been totally covered up with work lately and haven't had much free time. I'm pretty much done trying to get this amp/sub/Dirac combination figured out. I would like to maybe keep them if I can implement one of Brian's class D 600watt amps. I'm in the middle of correspondence with him now regarding that. If he can pull it off, I will consider going that route. I know it sounds crazy, but that's just what I feel this sub needs if Dirac is going to be used. I love the fact of having loads of headroom when driving any speaker and think for ME, this pairing comes up a bit shy. Just my experience and two cents.

Vince

OK, understand if you want to try something else.  Please, Please before you move on would you answer this question.  Have you confirmed one of the blinking LEDs indicates clipping or overdriving the sub amp input???  You previously assumed that was the case.  No amp is going to work correctly if the input is overdriven or bad in the first place.


dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #162 on: 27 Oct 2022, 11:39 am »
I will try and find time this weekend to try the full range speaker wires hooked up direct. Trouble is I would not set it up like this. And all I can say about the clipping indicators is that I was told to set damping to LOW to compensate for the clipping I would assume. Brian is out of the country right now and said correspondence may be slow. I waiting to hear back from a couple days ago.

77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #163 on: 27 Oct 2022, 12:35 pm »
I will try and find time this weekend to try the full range speaker wires hooked up direct. Trouble is I would not set it up like this. And all I can say about the clipping indicators is that I was told to set damping to LOW to compensate for the clipping I would assume. Brian is out of the country right now and said correspondence may be slow. I waiting to hear back from a couple days ago.

Really think you need to confirm if there is a problem on the input side of the sub amps.  You will never get a good outcome if the input signal is bad.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #164 on: 27 Oct 2022, 01:20 pm »
I will probably hook up a RCA break out to my oscilloscope to my sub outs, feed it with a signal and see at what voltage output it starts to clip. Although the amp clipping occurs regardless if I use sub outs at 1 volt or pre amp outs at 3.9 volts. I think it is a combination of using Dirac for bass management with this amp. It's trying to pull triple duty. Drive the subs drivers, correct for them and Dirac eats up headroom. These amps are having to do a lot themselves with regards to EQ just to keep the woofers in check with the signal.

Tyson

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #165 on: 27 Oct 2022, 03:24 pm »
Did you ever try the speaker level connectors?  It's dead simple, you just hook up some speaker wire from your amp main amp to the subwoofer amp, and then from your subwoofer amp to your main speakers.  That alone would clear up if the problem is the RCA input or not, because it would bypass the RCA input entirely.

There's also some argument to be made that the speaker level input is better than the RCA input from a sound quality standpoint.  So, worth trying.

hawkeyejw

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #166 on: 27 Oct 2022, 06:48 pm »
FWIW, jumping to a new amplifier when you’re clearly not getting the typical level of performance from the standard one is going to leave you with a good amount of risk that you end up with the same issue with the new amp. There’s 3 dead simple tests you can run (if you haven’t already) that should help you determine if your issue is with the sub amps or upstream:

1. Run the Spatials full range both with and without Dirac engaged and note the volume setting to SPL
2. Run the Spatials + subs using the speaker level inputs both with and without Dirac engaged
3. Run the subs by themselves (without the Spatials hooked up) using the speaker level inputs, both with and without Dirac engaged.

You mentioned only hitting 80db peaks during one of your test tracks, which unless you were listening to the subs alone does not add up at all. The Spatials with 400wpc available should be giving you way over 110 db unless you’re in an auditorium sized room. If you’ve tried the tests above and you’re getting normal SPL out of the Spatials both with and without Dirac, then there would seem to be something up with one or both sub amps. If that’s the case IMO it would make more sense to work with Danny to resolve and if needed get replacement amps, but it’s your choice/money. Good luck to you.

hawkeyejw

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #167 on: 27 Oct 2022, 07:00 pm »
I will probably hook up a RCA break out to my oscilloscope to my sub outs, feed it with a signal and see at what voltage output it starts to clip. Although the amp clipping occurs regardless if I use sub outs at 1 volt or pre amp outs at 3.9 volts. I think it is a combination of using Dirac for bass management with this amp. It's trying to pull triple duty. Drive the subs drivers, correct for them and Dirac eats up headroom. These amps are having to do a lot themselves with regards to EQ just to keep the woofers in check with the signal.

The only impact Dirac is going to have on the sub amp is possibly eating up tons of headroom. The processing is all done in your NAD so the amp is seeing an analog signal like normal. Based on my experience, it definitely is possible for Dirac to suck way more headroom than it should which would explain the issue. Hence why I asked if you tried with it turned off to compare SPL levels.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #168 on: 27 Oct 2022, 10:52 pm »



This is what I have configured. Subs only are playing, no mains ? Sub amps still clip at 80% on main volume. You can see the volume on the subs, I don't think this is out of line. No mains with or without Dirac engaged ?

77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #169 on: 27 Oct 2022, 10:55 pm »
I will probably hook up a RCA break out to my oscilloscope to my sub outs, feed it with a signal and see at what voltage output it starts to clip. Although the amp clipping occurs regardless if I use sub outs at 1 volt or pre amp outs at 3.9 volts. I think it is a combination of using Dirac for bass management with this amp. It's trying to pull triple duty. Drive the subs drivers, correct for them and Dirac eats up headroom. These amps are having to do a lot themselves with regards to EQ just to keep the woofers in check with the signal.

The Sub Amps servo control does not eat up power, headroom or result in too much for the amp to process.  As Danny said previously, DIRAC is not needed with that Sub amp/driver configuration.  DSP, EQ, or DIRAC should only be used to manage peaks - not boost levels to fill in dips.  Been there attempting to boost dips in FR. Does not work well to improve sound quality.  Tame the peaks is much more successful.

If you are dead set on using DIRAC, you do correctly identify your system configuration in DIRAC before running?  Could your listening position be in a room mode null causing DIRAC to overcorrect?

Get a Spectrum Analyzer App for your phone.  Find out at what Hz is the lowest tone the system produces without distortion that you can actually hear.  If you have REW both tone generator and Spectrum Analyzer are at your fingertips.   



   

77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #170 on: 27 Oct 2022, 10:59 pm »


This is what I have configured. Subs only are playing, no mains ? Sub amps still clip at 80% on main volume. You can see the volume on the subs, I don't think this is out of line. No mains with or without Dirac engaged ?

To be sure I understand.  Looks like the Sub amp volume is roughly 70%.  In addition, the Main Amp volume is at 80%.  Is that correct?

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #171 on: 27 Oct 2022, 11:10 pm »
Correct, that is when the Sub and LED's begin flashing on bass heavy tracks. Still no mains though ??

NoahH

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #172 on: 27 Oct 2022, 11:35 pm »
Correct, that is when the Sub and LED's begin flashing on bass heavy tracks. Still no mains though ??

I can't speak to why mains are not working in that, but it is not how recommended wiring would be done. You want to run the sub and mains in parallel, not serial.

But when you say you are getting clipping at 80%, is that the input clipping light or output? I would expect it to clip at 80% of your mains more or less - that is *a lot* of volume if you are using 400w. I would just not expect you to ever be near 80% of volume.

The more important question is what kind of volume you are getting now at whatever volume setting you run your NAD at normally. Is it still low?

NoahH

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #173 on: 27 Oct 2022, 11:38 pm »
I may have just realized the mains issue: that is a class D amp and they usually don't have a real ground output. You likely need to wire a touch differently. Your manual should have the info. Here is the REL doc on it since REL does high level inputs almost exclusively.  https://rel.net/blog/2017-12-27/how-to/connect-rel-class-d-gear/

77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #174 on: 27 Oct 2022, 11:44 pm »
Correct, that is when the Sub and LED's begin flashing on bass heavy tracks. Still no mains though ??

If you leave the Sub Amp volume at that setting, at what point on the Main Amp volume do the LEDs stop blinking?  Does one stop blinking before the other, or both operate in unison?  Or other way around.  Leave Main Amp at 80% and reduce the Sub Amp volume.  What do the LEDs do?

If it is correct that the LEDs indicate some kind of problem, then the problem on the input side must be solved.  It is either something faulty with the Sub amp input circuitry, fault with the Main Amp, or other mismatch somewhere in your system.  That combination of components should be able to produce SPL high enough to be painful.

Your room does not look to be large or filled with sound absorbing material.  Do you listen to the Spatial Audio Main speakers by themselves at 80% on the Main Amp Volume? 



dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #175 on: 27 Oct 2022, 11:52 pm »
Wow, interesting article I will have to check my manual. Just reconnected mains, work for another day.. thanks for all the input. I still have yet to hear from Brian, but did say he would be out of the country. Just really hopeful the new amp configuration is feasible.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #176 on: 27 Oct 2022, 11:58 pm »
I'm sorry, to answer your question, yes both amps clip within one Db of each other at the relative same time. You can tell it's stereo as bass peaks hit individually between left and right. And yes if I turn down the sub amp volume, the clipping goes away, as does the bass.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #177 on: 28 Oct 2022, 12:14 am »
I am going to quote Brian at Rythmik via e-mail when asked if I could turn the Sub system into a sealed system with just changing the servo boards out due to the fact I was not happy with the amp/sub configuration regarding headroom.  Just the fact it is an open baffle compared to a sealed sub with this same amp, the OB is at a disadvantage as far as output comparing the two.

This is what Brian had to say. And I believe everything he has to say on the subject as he has his Ph.D. in electrical engineering or something even more wordy :scratch:

" You know all OB main speakers and sub needs a 6db/oct correction which impact the efficiency.   Basically starting from 120hz, you cut the maximum output by 50% for every octave down.  There are two octave from 120hz down to 30hz "

Brian's words.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #178 on: 28 Oct 2022, 12:29 am »
The only impact Dirac is going to have on the sub amp is possibly eating up tons of headroom. The processing is all done in your NAD so the amp is seeing an analog signal like normal. Based on my experience, it definitely is possible for Dirac to suck way more headroom than it should which would explain the issue. Hence why I asked if you tried with it turned off to compare SPL levels.

Dirac on and off make only a few Db difference. I pretty versed in running Dirac room corrections, as I am well read on the subject and don't just let the processor do whatever it wants regarding black hole dips. I simply pull them down on the plot. I really think this OB sub needs a high power class D amp to play at realistic levels. I would love to see the performance difference.

 Danny... wouldn't you even be a little interested in knowing ? even for the opportunity to maybe up the game on your sub offerings ??? and please don't say the amp is perfect the way it is :duh: just pulling your leg, but seriously ?

77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #179 on: 28 Oct 2022, 01:02 am »
NoahH could have identified a potential issue.  M33 manual does say never connect the blue terminals to earth ground.  Could be a ground issue between the NAD and Rhythmic.

Also found in another forum long discussion about M33 owners having problems with DIRAC.  Distortion in the 20-100 Hz range.  Also, mention of problems across the entire frequency spectrum due to DIRAC erroneous corrections.  Some gave up on DIRAC, others "reset" M33, installed new firmware, and installed new version of DIRAC.

Suggest it may require discussion with NAD.  The way you describe the LED behavior on the sub amp, appears it is trying to protect itself (as designed) from a bad input signal - plain and simple.  Changing to a bigger amp or sealed box will not fix a problem with the source signal.