OB SUBS FINALLY WITH SPATIAL M3

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dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #20 on: 23 Sep 2022, 10:22 pm »
I just received an email back from Brian over at Rythmik audio. He said

"Hi Vince,
I haven’t tried that long cables so I cannot tell you if it will work.  Since the amp uses servo feedback, it is not wise to have feedback cable for that long. 
-Brian"

So for now I digress and yield my position I will get them wired direct soon.

Thanks guys, seriously don't mean to offend anyone here.

Danny Richie

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #21 on: 24 Sep 2022, 03:15 pm »
What you are sharing with us about the output levels, woofers bottoming out, and amps clipping is not consistent with what these woofers will do.

Something is a miss. I really suspect there is a polarity issue with the sensing coils, sensing coils not wired properly, or the polarities were not flipped when one woofer was flipped facing the other way.

These really should be bringing down the house flat to 20Hz with none of those issues.

We had dual open baffle servo subs under the Super V model at RMAF one year and we had so much really low bass output that it was freaking people out. When we play Deeper by Pete Belasco we thought the sheet rock was going to be pulled off of the studs in the room. We had people from the hallway come in and get us and have us go out in the hallway to see the walls outside our room. They were visually flexing 1/8 to 1/4 inches and we really thought we were about to break the sheet rock. 

These things will hit hard down low.

tom739

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #22 on: 24 Sep 2022, 05:09 pm »
As soon as I started to read this thread, I didn't think the cable length was an issue. I have the same pair of subs. I use a 6 ft cable between sub and Rhythmic amp. Mine work fine. I love the bass in my system. I do not play loud. But the bass is low, rich, and elastic. I have a pair of 2x12 OB and a REL T/9x in the back corner. 3 subs total. The volume is set fairly low on all 3.

Your issue about no documentation is spot on. The fact that none of these kits have a PDF file of best build practices and other important build info is defiantly a miss. The standard answer is to look through this forum. Ask your question there. Sure, that is good for unique questions, but the common stuff should be captured in a document. And the answers you get in the forum can be wrong, and ofter are. Not from Danny, but from the hundreds of others posting here. This thread is an example.

Creating an instruction document for each kit would take too much time.....  Nonsense.
Most of the doc could be a cut and paste from these forums, as Q&A happen, for the common stuff. Danny would oversee this, if not do it himself to be sure doc is correct. These sub kits have been in existence for over 10 years I think. Imagine how good the build doc would be by now. What's the full price of the kits for these 2 subs, with flat packs, and no simple doc?
Danny does great work! We just need a doc to answer common questions as we build, or before we buy.

Early B.

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #23 on: 24 Sep 2022, 06:25 pm »
Your issue about no documentation is spot on. The fact that none of these kits have a PDF file of best build practices and other important build info is defiantly a miss. The standard answer is to look through this forum. Ask your question there. Sure, that is good for unique questions, but the common stuff should be captured in a document. And the answers you get in the forum can be wrong, and ofter are. Not from Danny, but from the hundreds of others posting here. This thread is an example.

Creating an instruction document for each kit would take too much time.....  Nonsense.
Most of the doc could be a cut and paste from these forums, as Q&A happen, for the common stuff. Danny would oversee this, if not do it himself to be sure doc is correct. These sub kits have been in existence for over 10 years I think. Imagine how good the build doc would be by now. What's the full price of the kits for these 2 subs, with flat packs, and no simple doc?
Danny does great work! We just need a doc to answer common questions as we build, or before we buy.

Although I agree with you, better documentation is really the manufacturer's responsibility.

IMO, Rythmik Audio's website has plenty of information, in general, but it's highly technical and doesn't cater to the average buyer. A box sub is much easier to set up, but the cabinet build, wiring, positioning, and A370 amp controls for the dual OB servo subs are on another level. It's assumed that DIYers know what they're doing, so there's less hand-holding for anything beyond beginner kits, I suppose.     

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #24 on: 24 Sep 2022, 06:40 pm »
I agree about the info as well, This is a pretty important piece of information to not know about. I sure Danny, like he said will make it known on the site.

This is what I have for wiring, I am assuming these are nominal 16ohm woofer each and have them wired in parallel so the amp is seeing about a 8 ohm load give or take as its frequency dependent of course. So I don't know what else to check from here. The Servo side is a simple series connection at least per the wiring diagram. I used the wiring diagram with the two woofer configuration with the bottom woofer reversed, so therefor I can see where the wiring could trip up some people. the woofers are working together, just with a light touch on the surround's and you can verify that they are wired correctly. The Servo side is pretty simple as well.

Here is a close up of the wiring configuration. I have kept the wiring for the voicecoil  and the servo wiring on their respective sides of the build.
 



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dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #25 on: 24 Sep 2022, 06:44 pm »
Heck, I was even thinking of filling the speaker wire holes with black silicone just to have zero "unloading" of the woofer ?? I don't know if this would help or not, but I'm sure it couldn't hurt...

Danny Richie

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #26 on: 24 Sep 2022, 08:38 pm »
I can't really tell from your blue and white wiring which wires run back to the amp and are connecting to + and -.

To confirm or rule out the problem you could flip the polarity on the sensing coils at the amplifier.

It will either bring everything back under control and tighten everything up or get real out of control.

Be sure to test it at lower volumes first.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #27 on: 24 Sep 2022, 09:04 pm »
The wiring is correct Danny, but check this out! I had the genius idea to run splitters and feed both preamp inputs as Rythmik states you can gain 6db of input. So more is ALWAYS better right ? WRONG ! I opened both doors on the console so that I'm looking directly at the back of the amps. I played a series of tracks and low and behold one amp clipped at about 80% on the main volume and only got worse, the other amp however NEVER clipped ! totally different performance for sure !!!
Definitely put this in the "do's and don't" info on the kit ! I cant beleive I was simply overdriving the input stage and it never dawned on me to lose the splitters.... omg :duh: :duh: :duh:

Thanks again guys, and sorry Danny  :roll: 

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #28 on: 26 Sep 2022, 03:40 pm »




So today I completely tore everything apart verified wiring. Connected DIRECTLY to the amp leads, with the exception of the wire in the H frame, which I'm sure everyone has give or take an "inch or two". Hitting 80db peaks "with again Black Lotus by Walton playing just to see with these babies can do now that I have listened to all the BS. Amp falls apart badly, sorry folks. You can't see your LED's, I guarantee they are clipping at high levels and you don't know it. Now I'm a little pissed.

Danny, you said the walls were flexing so badly ??? these don't produce pressure in the room ?? they sound great if not pushed to hard period. I will be at some point probably switch to a sealed sub system that won't tax the amplifier. It would take four of these subs to get the same SPL as the mains without overdriving the amps. 115db at 25hz at 15 feet mic placement. Yeah, what the amp doing ?? and how would you know if its in a wooden box ? what's the distortion level ? I couldn't imagine the distortion levels...

I'll just be song selective when I show anyone "what these babies can really do"!

Sorry bout this post but I'm out thousands and 100 plus man hrs.

pics of amp in overload at 80% main volume
sub amp volume at 65%

Just to be clear, most songs with average bass clip at about 85-90% main volume, next I'm sure it will be my Integrated amp right...? Whatever at this point, it is what it is !




Danny Richie

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #29 on: 26 Sep 2022, 03:57 pm »
If you are hitting 80db peaks and clipping the amps then something is definitely wrong. That is NOT consistent with what we know they can do. It is quite the opposite. You should be able to hit 100+ db peaks (in your room) all the way to 20Hz with ease, and without even being close to overdriving the woofers or amps.

Also, one dual open baffle sub will hit harder while playing flat to 20Hz than a single sealed servo sub.

I would also like to help you figure out what is going on here and get you up and running so you can enjoy them.

Danny Richie

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #30 on: 26 Sep 2022, 04:00 pm »
Again, to confirm or rule out the problem can you flip the polarity on the sensing coils at the amplifier?

Also, disconnect the sensing coil and see if nothing happens. If it is still the same with the sensing coil disconnected that confirms a problem.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #31 on: 26 Sep 2022, 04:01 pm »
I hate to get down on anything about this Danny but I am at a loss my friend.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #32 on: 26 Sep 2022, 04:02 pm »
I will try that and report back.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #33 on: 26 Sep 2022, 04:11 pm »
OK, the Servo section is definitely doing its thing! woofers were totally unleashed without it. If the speaker didn't weigh 100 pounds plus I would ship you the speaker Danny.

BGA

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #34 on: 26 Sep 2022, 04:20 pm »
I see you are using an NAD int, are you using Dirac to do room correction? I have dual 12 OB and never had any issues with the amp clipping but with Dirac on a miniDSP I had it bottom out a couple times when DIRAC was trying too hard to correct a dip in response. It doesn't take much overdrive an amp when correcting dips with DSP.

Just for a reference in my theatre I use dual Rhythmic sealed 15" subs and for music and to match your M3s I think you may not like the sealed versions with your M3s, they completely load the room differently.

Tyson

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #35 on: 26 Sep 2022, 04:31 pm »
Oh, if you're using Dirac, you should definitely remove that from the signal path (or disable it).  That can definitely cause clipping with attempting room correction, as BGA notes.

dallaire1

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #36 on: 26 Sep 2022, 07:10 pm »
Yes it does want to create a flat response when it see's a dip, and yes for sure its to be used with caution especially in the low end but I limit its correction if there is a black hole null at a particular frequency and make sure it doesn't over correct as you can alter the curve ones self. To be honest, I think what it does with regards to phase matching and setting x-over points is pretty amazing as an integration tool. I have played back and forth with it ON and OFF and it makes a few Db difference.

I can make them sound great I just can't get much output from them. My wife wants to drive them to Danny's so he can take a look laughingly, but I have considered it. I am just at a loss in regards to output only, there is only a subtle difference when defeated, I'm so confused at this point.

Early B.

Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #37 on: 26 Sep 2022, 08:50 pm »
My wife wants to drive them to Danny's so he can take a look laughingly, but I have considered it.

Listen to your wife.

Tyson

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #38 on: 26 Sep 2022, 09:57 pm »
How many db are you hitting when the amp clips?

77SunsetStrip

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Re: OB SUBS FINALLY WITH SPATIAL M3
« Reply #39 on: 27 Sep 2022, 01:16 am »
dallaire1, sounds like you have eliminated most of the easier to correct problems.  I would next verify that the source signal to the sub amps matches the specified input range.  For example, sub amp max input voltage rating 2.5 V.  If you supply more than 2.5 V, the amp is not going to behave well. 

Flat to 20Hz can sound desirable in theory, but might not work out well in practice.  There is almost no musical content below 30 HZ, unless synthesized or a huge pipe organ that can go down to 16 Hz.  I chased meaningful output below 40Hz with a Ripole sub driven by a sub amp with DSP.  Increasing the output at 35 Hz, 30 Hz, 25 Hz or 20 Hz did nothing but increase cone excursion to ridiculous levels without achieving gut pounding bass. In fact, just muddied up everything.  Setting 6db per octave roll-off below 40Hz and adjusting for as flat as possible in room response from 60 - 100 Hz yielded the best overall bass impact and clarity.