OB SUBS FINALLY WITH SPATIAL M3

dallaire1 · « **Reply #100 on:** 10 Oct 2022, 01:20 pm »

Okay then, again the wiring is correct. It's pretty basic, Danny has me second guessing myself because we just keep going in circles. Just wanted to make EXTRA certain. Like I mentioned, I'm contacting Brian at Rythmik today to get the official answer.

Brian Ding <briand@rythmikaudio.com>

dallaire1 · « **Reply #101 on:** 10 Oct 2022, 01:54 pm »

I've emailed Brian Ding at Rythmik, I will post his answer when it comes in. Thanks

77SunsetStrip · « **Reply #102 on:** 10 Oct 2022, 01:56 pm »

Quote from: dallaire1 on 10 Oct 2022, 12:28 pm

Both woofers are to move forward together right? Regardless if they are backwards in relation to one another? The bottom woofer moves toward my front wall as the top woofer moves toward me at the MLP? right?? I just want to be clear.

Agree with the need for clarity. All FOUR woofers must move in unison, all cones in the same direction at the same time. From the MLP, all four cones must move in unison toward you, then away - regardless of their installation orientation. Your description is not clearly conveying that operation.

dallaire1 · « **Reply #103 on:** 10 Oct 2022, 02:02 pm »

Well I guess I could simply reverse the two speaker wires on the top woofer to verify. It will either blow the windows out or produce even less output. I'm working right now but will try this just for the heck of it.

dallaire1 · « **Reply #104 on:** 10 Oct 2022, 03:03 pm »

Above is a link to a video I took with the OB subs, amps are A370PEQ. I have dual sub outs on my NAD M33 that I am using, the sub amp settings are (28hz, mid-level servo control), crossed at 40hz. Both amps seem to clip at about 80% on the main M33 volume dial ? I have checked the wiring of the subs many times, they are correct per the schematic with opposing woofers. I have defeated Dirac per Danny’s direction. (Doesn’t seem to matter if I use Dirac or not) amps volume is at 5 clicks past center. Only clips at 80% volume and up ? I have NO cables on this system to the subs, direct wiring.

Please advise thanks,
Vince

ORIGONALL TRANSMISSION TO BRIAN

dallaire1 · « **Reply #105 on:** 10 Oct 2022, 03:04 pm »

Hi Vincent,

Please first try 28hz low damping instead of medium damping. Second, OB subs are less efficient and I assume you have known the fact. If the drivers are wire incorrectly, the bass will not sound right. Third, how do you crossover between your OB mains and OB subs? Xover frequency? And distance setting in AVR of sub and main speakers? If your phase is not correct, you can get cancellation between sub and main speaker.

-Brian

BRIAN RESPONSE

dallaire1 · « **Reply #106 on:** 10 Oct 2022, 03:06 pm »

Thanks Brian, I have used Dirac to set the crossover points and set phase. Even with Dirac defeated I have them crossed at 40hz, doesn’t seem to matter if Dirac is ON or OFF. They are crossed at 40hz to my mains. The integrated amp NAD M33 is driving a 4-ohm set of main speakers (SPATIAL AUDIO M33’S 92dB 1W/meter sensitivity. The M33 puts out 444 peak watts per channel into 4-ohm loads. Could I simply be expecting to much from the plate amp with THIS subwoofer design ? I am assuming in a OB design it takes a lot from the amplifier to keep the OB design on track with the signal compared to say a “sealed design” ? I have checked the wiring 30 times per the schematic and is correct. Sound is tight and controlled and evident until I push the volume on my Integrated to 80%, I will put the control to “low” at “28” to gain more headroom. I thought this design at GR was proven to play very loud as I have read.

Vince

Danny Richie · « **Reply #107 on:** 10 Oct 2022, 03:19 pm »

Quote from: dallaire1 on 10 Oct 2022, 12:28 pm

I will take a pic of the plate amp settings and post today. Also going to just start emailing Brian at Rythmik to just jump to the end of this whole thing. I already know what the answer will be. I'm already searching for new amps but seems as though Rythmik has the servo control market sewed up. But I will find a solution. I checked the wiring again last night. Both woofers are to move forward together right? Regardless if they are backwards in relation to one another? The bottom woofer moves toward my front wall as the top woofer moves toward me at the MLP? right?? I just want to be clear.

That is not really in question. I am wondering if the polarity of the servo sensing coils are correct.

I have another question for you too, or something you can try.

Please run a speaker cable from your amp or speakers to the servo amp and try using the speaker level inputs and let me know what happens.

jn316 · « **Reply #108 on:** 10 Oct 2022, 03:21 pm »

Quote from: 77SunsetStrip on 10 Oct 2022, 01:56 pm

Agree with the need for clarity. All FOUR woofers must move in unison, all cones in the same direction at the same time. From the MLP, all four cones must move in unison toward you, then away - regardless of their installation orientation. Your description is not clearly conveying that operation.

This sounds like the problem to me...they are going in opposite directions.

dallaire1 · « **Reply #109 on:** 10 Oct 2022, 03:37 pm »

I will try these things when I can break free. Hell, I could still have them wired wrong ? I will try and post pics of up close wiring so you guys can determine if they are correct or not. I have checked so many times, I'm starting to doubt myself

I just want to get this right, not looking to prove anything to anybody.

dallaire1 · « **Reply #110 on:** 10 Oct 2022, 03:40 pm »

Danny, can't I simply reverse the two wires on the top sub to verify. Loss of sound or much more sound from subs will tell in my mind correct ?

dallaire1 · « **Reply #111 on:** 10 Oct 2022, 03:42 pm »

“ I am assuming in a OB design it takes a lot from the amplifier to keep the OB design on track with the signal compared to say a “sealed design”

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.

Your M33 is also OB so it also suffers the limitation of OB speakers. Most GR customers use their subs with Danny’s main speakers. It has proper crossover and drivers will not fight each other. I cannot so sure about M33 if they are “subwoofer friendly”. A lot of main speakers are not subwoofer friendly. For instance, if the main speakers do not have flat low end frequency response, then you cannot properly integrate sub until you put a high pass on main speakers at say 80hz. The purpose is to provide a “text-book like” frequency response for main speakers. How does M33 tackle the problem of 6db/oct roll-off? Does it have electronic compensation network? Otherwise the output between 80hz to 40hz may be 6db down and phasing become an issue etc. The old Klipsch horns like Cornwall, Lasacala, etc are have this problem. It is almost a hit-or-miss try to integrate without HPF on main speakers.

-Brian

Danny Richie · « **Reply #112 on:** 10 Oct 2022, 03:45 pm »

Quote from: dallaire1 on 10 Oct 2022, 03:40 pm

Danny, can't I simply reverse the two wires on the top sub to verify. Loss of sound or much more sound from subs will tell in my mind correct ?

If the woofers are all moving in the same direction then the wiring is correct on the driver coils. Loss of control is typically an issue with the sensing coils.

dallaire1 · « **Reply #113 on:** 10 Oct 2022, 03:49 pm »

I have measured the M3 main speakers with REW and they roll off in my room sharply at 37hz. They measure very well indeed. If I had to guess Clayton Shaw at Spatilaudio has implemented a 6db boost in his crossover design to get that low. But again, this is taken care of by the NAD amp. It has clipping indicators on the front but have never seen then lit.

Vince

BACK TO BRIAN

dallaire1 · « **Reply #114 on:** 10 Oct 2022, 03:53 pm »

Ok, I will do the "battery" test 9volt at the Speakon connector to verify driver motion direction.

dallaire1 · « **Reply #115 on:** 10 Oct 2022, 03:53 pm »

and triple check the series connection with the servo portion of the amp AGAINL.

dallaire1 · « **Reply #116 on:** 10 Oct 2022, 04:06 pm »

Here is the frequency response at the MLP Brian.

dallaire1 · « **Reply #117 on:** 10 Oct 2022, 04:34 pm »

This plot does not look good either. You can see that you have +5db at 30hz and -6db at 50hz. 50hz is more audible than 30hz, so you keep turning up the volume. You need to find a way to eliminate the -5db at 50hz without using Dirarc (because it is just an EQ on composite response) and find out why you have +5db at 30hz.

Also plot it down to 14hz or 10hz to see the entire roll-off characteristic. Right now just based on the plot, you will say your subwoofer volume is too high which is why +5db at 30hz and it causes a cancellation at 50hz, which is caused by incorrect phasing. Hence OB sub is clipping.

-Brian

BRIAN RESPONSE

Bingenito · « **Reply #118 on:** 10 Oct 2022, 04:41 pm »

Peanut gallery here

Could be wrong but if that is mlp you and or the subs could be in a suck out and trying to compensate with correction could easily cause what your issue is.

Try moving the subs a few (5-6”) inches forward and back and see how it helps. Sounds stupid but works.

dallaire1 · « **Reply #119 on:** 10 Oct 2022, 04:46 pm »

Yeah, I’m a little limited on sub placement as one cannot insert a speaker cable between amp and sub, as it will ruin the servo control over the drivers. I would have no choice but to build amp boxes. As for the low end response, I’m afraid its my room simply dictating the low-end response I’m going to get. So you think I should implement the PEQ and bring down the 30hz region in hopes to bring up the 50hz region ?

Vince

RESPONSE TO BRIAN