OB SUBS FINALLY WITH SPATIAL M3

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hawkeyejw

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #180 on: 28 Oct 2022, 01:25 am »
Thanks for the additional details, definitely helpful.

Something else I’m wondering that may have been discussed, if so my apologies. Have you tried playing one sub at a time? I’m not sure what process you’ve done to align the phase of your dual subs but if they’re out of phase with each other based on room placement, that could suck all your headroom out too.

I still am trying to figure out why you can’t achieve the same SPL with these that others consistently have. Sure you can get a lot more SPL with any number of monster subs that are on the market but if you’re at 80 db when you should be getting 100+, something is wrong in the chain.

Hope you’re able to figure it out.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #181 on: 28 Oct 2022, 11:05 am »
If amplifier power is not utilized to correct sub driver overshoot etc. Where does the additional power come from ??? It's all one system. The amp constantly EQ's the drivers, takes power from somewhere.

NoahH

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #182 on: 28 Oct 2022, 12:11 pm »
If amplifier power is not utilized to correct sub driver overshoot etc. Where does the additional power come from ??? It's all one system. The amp constantly EQ's the drivers, takes power from somewhere.

It's not quite like this is a discrete thing the amp does. Servo control is basically the same thing as global negative feedback, which your purifi modules do as well. It is looking at the position or velocity of the drivers and, if it is not where the system expects, adds or removes some input voltage before the amp stage. So it can mean adding more input, which eats headroom, but we are not usually talking about a massive portion of signal. Your purifis could have the same core thing happen - their output is a little weak so the feedback mechanism adds more input, eating some headroom.

The bit about 80% volume clipping does not seem like an issue because *if you ever have to turn the volume on your m33 that high, you have bigger issues*. The question is why it needed to go.up that far anyways. The diagnostic challenge is that the M33 is kinda inscrutable for what it is doing. Ex. I glanced at the manual yesterday and the sun outs and line outs are different voltages, which is really weird. The bigger issue is that it is filtering frequencies, and I would not bet on knowing if they are all defeated at any moment. In retrospect, I worry that your test with the speaker level inputs may have lacked bass signal because the m33 was removing that from the mains signal.

Your idea to run a rum signal from an oscilloscope to amp is good. If you have a normal DAC or anything anywhere in the house,.running it straight to the amps is good.

77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #183 on: 28 Oct 2022, 01:09 pm »
NoahH is correct regarding the Servo control operation prior to the amplification stage.  There is no loss of output Watts due to the Servo system.  I looked at the M33 user manual.  Lots of features and capabilities with many options for the user to make choices.  If it were me, would start at zero with the M33 setup.  If the Spatial Audio speakers are not painfully loud at 80% volume, there is something wrong in the M33 configuration or electrically amiss. 

It could be as simple as a ground issue between the M33 and Rhythmic amps.  Talk to NAD about how to correctly physically connect to a sub amp and correctly set up the M33 for best performance.

Respectfully suggest putting aside some of the pre-conceived notions expressed about open baffle subs and amplification power.  Assume nothing, very everything from the start of the signal path. 

jn316

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #184 on: 28 Oct 2022, 04:18 pm »
Could you borrow someone else's integrated amplifier and see if that fixes the problem? Phoenix is a large city...surely someone would be willing and able to come over and try this very simple test.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #185 on: 28 Oct 2022, 08:07 pm »
Yes it sounds as like I need to get with NAD and ask if there is something special I should know about hooking up class A/B sub amps ? I thought the article in the link regarding the REL's was interesting. As far as listening to the M3's at 80% on the dial, that is almost always with Dirac engaged. Which is a solid 3Db lower if not a bit more, but as we all know 3Db can sound half as loud depending on the individual. The NAD definitely has all the dynamic headroom into 4 ohms I could ever need. The subs however are two 16ohm nominal drivers wired in parallel which should indicate an 8ohm nominal load on the sub amp. So I would think the mating of the two are incredibly out of kilter. Nothing clips till heavy bass peaks hit at again 80% main volume. If the NAD was driving 8ohm mains I'm sure it would be a more in line match up.

When I hooked up using speaker level connection's only the Subs worked, still clipped sub amp's at same volume. The rest of the signal never passed through to the mains ?  This again may be like the REL scenario ?

I still have yet to hear back from Brian at Rythmik regarding trying the 600watt class D amp and swap out the OB servo boards to the larger amp.

I will get with NAD when I can and repost.
Thanks ! 

77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #186 on: 28 Oct 2022, 10:04 pm »
Figuring out if there is some kind of mismatch between the NAD and Rhythmic amps is a must.  Simply switching to a different sub amp could leave you with the same mismatch problem.  I am becoming highly suspicious of a DC offset causing the flashing LED on the Sub amp input.  No Sub amp will like that situation.

Still a head scratcher that it requires 80% of full volume on the NAD to reach the listening level you prefer.  I know this is time consuming and frustrating, but there will be a solution discovered.   

Danny Richie

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #187 on: 28 Oct 2022, 10:38 pm »
Quote
" 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.

Loading them in an H frame design increases front to back separation and output down low. The shelving circuit designed for the OB operation will flatten the response to 20Hz and lower.

Quote
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 ?

We've used the HX800 amps. It produces 400 watts per channel from each amp.

The A370 can drive a pair of duals to peaks of 115db down to 20 to 25Hz with no issues and with headroom to spare, and that is in a pretty good sized room measured from 13 feet away. So the amps have plenty of power. I have the same amps driving a pair of triples in my room. They never run out of power. The amps are not the issue.

I would relook at the sensing coils and trying flipping the polarity on each one of them one at a time and note the differences. It really sounds like one is flipped.

Danny Richie

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #188 on: 28 Oct 2022, 10:45 pm »
Quote
I still have yet to hear back from Brian at Rythmik regarding trying the 600watt class D amp and swap out the OB servo boards to the larger amp.

Brian is out of the country right now. So you will not hear back from him soon, but I can tell you unequivocally that a bigger amp is not the solution. You have plenty of amp. 

I would also highly recommending getting rid of Dirac and implement a LOT of real room treatment. Your system is never going to reach any real performance levels with all of those bare walls. Some good room treatment will be the best investment you make in your whole system.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #189 on: 28 Oct 2022, 11:25 pm »
So that's the answer.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #190 on: 28 Oct 2022, 11:42 pm »
Danny, I have verified the wiring 157 times. I have gone and hooked up to the pre-outs instead of the sub-outs as it gave me a 3Db increase on the volume dial. So that is good. Here's the issue I have, due to the OB design itself requires an additional +6Db EQing out of the gate ! That is a LOT of lost power is it not. Clipping is clipping is clipping....I'm sorry

Is there such a thing as too much amplifier in audio ? it eliminates clipping.

" 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 #191 on: 29 Oct 2022, 12:35 am »
sorry wrong post

Tyson

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #192 on: 29 Oct 2022, 12:39 am »
Try removing the NAD from the signal path.  Do you have another amp/preamp you can use temporarily?

hawkeyejw

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #193 on: 29 Oct 2022, 01:10 am »
Danny, I have verified the wiring 157 times. I have gone and hooked up to the pre-outs instead of the sub-outs as it gave me a 3Db increase on the volume dial. So that is good. Here's the issue I have, due to the OB design itself requires an additional +6Db EQing out of the gate ! That is a LOT of lost power is it not. Clipping is clipping is clipping....I'm sorry

Is there such a thing as too much amplifier in audio ? it eliminates clipping.

" 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.

All of this is not relevant though if you are getting 80db peaks when others are at 100+ with the same subs in a similar room.

I know I asked above but I didn’t see an answer, have you tried playing the subs one at a time? I’m guessing you did adjust the delay on the subs to time align them with each other but if not, it’s another easy test to check as the subs being out of phase with each other could definitely cause this issue.

NoahH

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #194 on: 29 Oct 2022, 01:14 am »
Yes it sounds as like I need to get with NAD and ask if there is something special I should know about hooking up class A/B sub amps ? I thought the article in the link regarding the REL's was interesting. As far as listening to the M3's at 80% on the dial, that is almost always with Dirac engaged. Which is a solid 3Db lower if not a bit more, but as we all know 3Db can sound half as loud depending on the individual. The NAD definitely has all the dynamic headroom into 4 ohms I could ever need. The subs however are two 16ohm nominal drivers wired in parallel which should indicate an 8ohm nominal load on the sub amp. So I would think the mating of the two are incredibly out of kilter. Nothing clips till heavy bass peaks hit at again 80% main volume. If the NAD was driving 8ohm mains I'm sure it would be a more in line match up.

When I hooked up using speaker level connection's only the Subs worked, still clipped sub amp's at same volume. The rest of the signal never passed through to the mains ?  This again may be like the REL scenario.

Ask NAD about the behavior overall. Unless your room is a concert hall, there is something very strange happening in general. If you are running at 80% with a 400w amp, to get the main volume where you need it, something is up. Class D watts are usually a little anemic vs class A watts, but that is still really extreme. People go to 80% with smaller tube amps, not with amps like that. For an example, I am using an 75 watt tube amp with my mains in a room that is effectively about 1500 sqft (open plan) and 75% volume is too loud to be in the room with. Different speakers that are a little more sensitive, but not world's more.

Related - amps get further outside their linear range when you push them usually, so your quality is likely degraded. *Note that everything I am saying is separate from the sub questions.* I suspect NAD will tell you that you need a second amp added so you can run them in mono mode or that something else is up.

All the above also reminds me - if you bought the NAD from a dealer, you might ask them to visit. Good dealers will do that.

77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #195 on: 29 Oct 2022, 03:28 am »
Danny, I have verified the wiring 157 times. I have gone and hooked up to the pre-outs instead of the sub-outs as it gave me a 3Db increase on the volume dial. So that is good. Here's the issue I have, due to the OB design itself requires an additional +6Db EQing out of the gate ! That is a LOT of lost power is it not. Clipping is clipping is clipping....I'm sorry

There have been very patient efforts here to help you.  At this point I have to be blunt, Sorry.  It makes NO sense that you have to run the NAD at 80% of max volume.  That is the first problem you need to deal with.  You may need a new DIRAC installation or other update from NAD.  There are reported cases of problems in those areas.

Secondly, a blinking LED on the Sub amp input indicates a problem with the source signal - again pointing to the NAD.  Has nothing to do with Open Baffle design or available Sub amp Watts. 


77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #196 on: 29 Oct 2022, 03:35 am »
The NAD definitely has all the dynamic headroom into 4 ohms I could ever need. The subs however are two 16ohm nominal drivers wired in parallel which should indicate an 8ohm nominal load on the sub amp. So I would think the mating of the two are incredibly out of kilter. Nothing clips till heavy bass peaks hit at again 80% main volume. If the NAD was driving 8ohm mains I'm sure it would be a more in line match up. 

Sorry, one more thing.  The Main speakers Ohm rating and the Sub drivers Ohm rating are irrelevant to mating the two.  Volume control on each amp is how you match the sound level of each to your taste. 

EdwardT

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #197 on: 29 Oct 2022, 12:52 pm »
Maybe I missed it somewhere on the last 10 pages of discussion but what did you find when you plugged your phone directly into the sub (s) and played a music file? Nothing fancy, just a 1/8” to rca adapter and any mp3, just hear the sub work.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #198 on: 29 Oct 2022, 07:20 pm »
Well no sense going with the Rythmik 600 watt amp. Just looked at the specs, they are rated at 600watts into 4 ohms, or 200 watts into 8 ohms. So NOTHING will change. Even the A370PEQ says 370watts but doesn't state what ohm load at 370watts. Whatever anymore, seriously.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #199 on: 29 Oct 2022, 07:22 pm »
So that 370watt amp may only be putting out 180watts per driver, who knows....