[dayneger]

I'm working on some design variations that leverage servo subs and am trying to see how to integrate the amps into the speaker footprint.  This isn't easy because of the sheer size of the amps, but detailed dimensions could help.


Any chance you could measure a few things for me?  Inches or mm are both fine.



- How thick is the mounting plate?
- How high do the features stick up above the top of the plate?  (heat sink, knobs, etc)
- Is there an inside "cover" over the guts of the amp, or is it closed?  If so, how deep is it below the underside of the mounting plate?
- If there isn't a cover, how far does the deepest thing hang down below underside of the mounting plate?
- If there isn't a cover, does the depth of the features (transformer, etc) vary across either of the two dimensions?  This could be depth (height) tapering down from one end to the other, be it in the long direction or (possibly better) across the shorter direction.


Thanks!


P.S.  Areas I'm considering... particularly mounted inside the "wing":


 
 


or in a lateral orientation:
  

[Early B.]

As you create your designs, keep in mind that you're gonna have a cable and a power cord shooting out of the back of the amp, plus you need to easily see and gain access to the settings. The best solution is one that doesn't create other problems. Or you may be seeking a solution to a problem that doesn't exist.

My suggestion -- create more modular designs. Give yourself and others plenty of stackable options, including an integrated amp module. Over the years, I've had several speakers, all of which sat on top of the same subwoofer cabinets. We're audiophiles -- we trade stuff out all of the time. Let's say you build one of your designs. Three months later, you'll want to try a different pair of speakers, but you'll be stuck with one-of-a-kind, custom-designed, but hard-to-ship-and-sell cabinets.     

[dayneger]

My suggestion -- create more modular designs. Give yourself and others plenty of stackable options, including an integrated amp module. Over the years, I've had several speakers, all of which sat on top of the same subwoofer cabinets. We're audiophiles -- we trade stuff out all of the time. Let's say you build one of your designs. Three months later, you'll want to try a different pair of speakers, but you'll be stuck with one-of-a-kind, custom-designed, but hard-to-ship-and-sell cabinets.   

That's definitely a good suggestion!  And it's a debate that's raged internally in my little pea brain for a while now... seamless appearance vs modular flexibility?

For the moment I'm leaning toward seamless, for a couple of reasons.  One, I'm seeing if I can figure out a design that's not incredibly difficult to redo if need be (as in, make a different cabinet set).  Two, knowing that I don't have much time for this hobby so it tends to come in "surges".  I tend to get things set up and run with it for quite a while.

Ideally I'd have the time and free cash flow to trial a whole bunch of ideas and explore different mix and match pairings, but that doesn't match well to my real world.

So, any chance you could stick a tape measure and/or calipers on one of your amps? 

[Early B.]

So, any chance you could stick a tape measure and/or calipers on one of your amps? 

The amps are 12.5" x 10.25" and 7/8" outwardly deep (heat sinks). The guts are about 4" deep. I couldn't use a caliper to measure the thickness of the amp since mine are mounted in cabinets that are 5" deep, but the metal plate is around 1/8" thick. Hopefully, others will chime in with their own measurements.   

[kaplanent]

Hi,

First time posting here. But have been reading and learning from this site for years. And of course a lot of other websites.
I got the speaker building bug a long time ago, when I realized I could never afford to buy the high-end speakers that I used to hear in audio salons.
Finally advanced to the stage where I use SolidWorks to do all the design work now. (I bought it for my electrical engineering consulting business).

The reason I'm posting now, is that I have almost fully modeled the A370PEQ amp in SolidWorks (sans the silkscreen. Still have not had success importing text overlay). I sure you can relate to how time consuming that can be.
I'm offering to share the assembly model to help "dayneger", but not sure the best way. It's quite large, so maybe through my Dropbox account.

I realize I have to post 3 times before we can PM for emails, so lets chat so I can help.

Regards,

Alan

[dayneger]

Hi Alan, that would be sensational! Thank you so much for offering to share the results of your hard work, and absolutely, I'm too familiar with the level of effort involved.

Please feel free to leverage this thread to build your posts. For example, which speaker design inspired you to model the A370PEQ? Or how did you choose SolidWorks? (I'm on Creo, but no problem to import).

@Early B., many thanks as well for sending over what you were able to measure. I was hoping for no more than 4" of total depth, but it sounds like it might be more.

Edit: corrected a typo

[kaplanent]

Hi dayneger,

What inspired me was the BG line arrays and servo-sub stacks. Many thanks to Danny's and everybody's posts of invaluable information.
I have been experimenting with hybrid line arrays for the home theater.
I never had enough of the NEO10 or NEO3PDR's to do a real 7ft line array.
I finally purchased 12 NEO10 and 36 NEO3PDR's over the past 3 years.

An epiphany came to me while making everything one piece and instead try to do a modular speaker system that is easy to assemble in place.
A dual triple servo-sub stack with the amp in a bottom chamber weighs about 175lb.
Try maneuvering those in a small space behind an acoustically transparent screen.
What if each piece was no heavier than 50lb.

My interim solution, until I had enough NEO drivers, was to use the RS180-8P and the PT2C-8 planer designed by Bob Carver.
I heard his line arrays one year at the New York Audio Show. It was a very large room and they sounded petty impressive albeit a little larger than life.
The PT2C-8 is closed back but I let the RS180-8P be dipole. 10 woofers, and 10 tweeters, all bi-amped.

I decided to go with SolidWorks, because we had both at my day job (I'm retired now), and I found it much easier to learn than Creo. I'm an electrical engineer, not mechanical, but I got involved in the packaging aspect of my work.

I checked my model and the depth seems to be 3.75".

Here are some pictures of the amp module and behind the screen with the screen lifted up.

[dayneger]

Holy smokes!!  You mean business!!   
That's a seriously intense rig that demands its own dedicated thread.  It would be very interesting to see what your listening impressions have been along the journey, along with screen and projector choice and lots of other fun details.   

Your amp model looks remarkably detailed and precise.  That's certainly not one you knocked out in 20 minutes.

Does the inside of the amp have a removable cover?  I might mount mine in a fashion where they don't need to hold seal, and the components on the back might let me integrate things better if not all the same depth.

I'm expecting to have my speakers sitting on mostly hidden high-load wheels/casters since my current design ideas would be ridiculously heavy.

[dayneger]

Looks like I can answer my own question about the distribution of the components.

This appears to be the right one?



How tall are those power caps?  That transformer looks pretty deep.

[kaplanent]

Hi dayneger,

Right, that's how I determined the max depth of 3.75", which is the toroid.
So I take it you don't have the amps yet?

regards,

Alan

[kaplanent]

Hi dayneger,

I missed your previous post before posting a new one.

The amp does not have a cover. I just added the extrusion on the back to represent the max depth. It's all open as the picture you posted above.
My model is accurate as to the mounting plate and holes, and the components are as close to there positions as possible.

Thanks for the compliment on my theater/music room.
I agree ate some point it should be a dedicated thread.

As an overview:
It took me 8 years to get it to where it is now. It will never be 100% done as they say.
Projector: JVC NX-7 (upgrade from the Panny 7000)
Screen: Seymour AV custom Enlighter 4K acoustic transparent. 2.35:1, 125" wide x 53.2 high (not diagonal, I feel that's meaningless).

The theater size is about 13ft wide, x 20ft long, and 7.5ft high in the basement.
In addition to the 6 servo-subs up front, I have 4 sealed 15"subs in the rear of the theater.
2 Sono-tube designs vertical, about 7cuft, and 2 in the second row risers (Why waste that space, about 7cuft each half).

The rest of my custom speakers and equipment is nothing special. I'll save that for another time.

Regards,

Alan

[Early B.]

The theater size is about 13ft wide, x 20ft long, and 7.5ft high in the basement.
In addition to the 6 servo-subs up front, I have 4 sealed 15"subs in the rear of the theater.
2 Sono-tube designs vertical, about 7cuft, and 2 in the second row risers (Why waste that space, about 7cuft each half).

You certainly understand the benefit of multiple subs!! 

[dayneger]

As an overview:
It took me 8 years to get it to where it is now. It will never be 100% done as they say.
Projector: JVC NX-7 (upgrade from the Panny 7000)
Screen: Seymour AV custom Enlighter 4K acoustic transparent. 2.35:1, 125" wide x 53.2 high (not diagonal, I feel that's meaningless).

The theater size is about 13ft wide, x 20ft long, and 7.5ft high in the basement.
In addition to the 6 servo-subs up front, I have 4 sealed 15"subs in the rear of the theater.
2 Sono-tube designs vertical, about 7cuft, and 2 in the second row risers (Why waste that space, about 7cuft each half).

Geez, thanks Alan, now you have me dreaming about an acoustically transparent screen setup!  As though I didn't already have enough on the wish list already! 

I think I'm still struggling to imagine two 6-driver servo subs up front and 4 sealed 15" subs in the back of a room that size.  Nice projector, too!

Exactly, I don't have the amps yet.  I'm working on dialing in a design that I think will work for my space before ordering materials.

Looking at the back of the amp, it's making me wonder whether I could "move" the transformer to a different location by extending its leads, and maybe solder the power caps at a flatter angle if possible in order to make it a flatter pancake that's easier to hide.

[Early B.]

I think I'm still struggling to imagine two 6-driver servo subs up front and 4 sealed 15" subs in the back of a room that size. 

My room is nearly identical in size to kaplanent and I can definitely imagine how phenomenal the sound could be, even for a 2-channel system. 

[Danny Richie]

Facing the 12 inch servo subs towards each other like that will cause a big increase in pressure that will be like putting them in a small spaced band pass cabinet. So it will cause a huge hump in output somewhere and an earlier roll off. It will create high SPL at the peak, but will not be linear at all.

[dayneger]

Facing the 12 inch servo subs towards each other like that will cause a big increase in pressure that will be like putting them in a small spaced band pass cabinet. So it will cause a huge hump in output somewhere and an earlier roll off. It will create high SPL at the peak, but will not be linear at all.

Trying to understand and learn here... are you saying that all S.L.O.B. and ripole designs fundamentally will behave this way?  Or is there something different about the way the servo subs would interact with slot-loading that would cause a problem? 

Could active EQ mitigate or even remove the problem?

I was assuming that as long as the Sd of the two drivers didn't get compressed down too far, that it would work fine.  Would any degree of compression be ok?  For example, output cross-section being 70-80% of the combined Sd?

[Danny Richie]

Trying to understand and learn here... are you saying that all S.L.O.B. and ripole designs fundamentally will behave this way?  Or is there something different about the way the servo subs would interact with slot-loading that would cause a problem? 

Could active EQ mitigate or even remove the problem?

I was assuming that as long as the Sd of the two drivers didn't get compressed down too far, that it would work fine.  Would any degree of compression be ok?  For example, output cross-section being 70-80% of the combined Sd?

That large amount of loading of the woofers will change the Q and make them act more like they are in a small box. So it will hump up the response and cause a peaked area. The servo system will not like trying to compensate for it either.

It also creates large unbraced areas that will cause resonance issues.

Woofers used in designs like that need to have mechanical parameters that are designed for it. Then it will take large amounts of EQ to get them to play down low.

The servo sub system is well designed and used as intended they will give you the best sounding bass response that there is and play flat to 20Hz.

I would highly recommend using them as designed to get good results.

[dayneger]

That large amount of loading of the woofers will change the Q and make them act more like they are in a small box. So it will hump up the response and cause a peaked area. The servo system will not like trying to compensate for it either.

I don't actually care whether the servo system "likes" trying to compensate for it as long as it does it well and doesn't blow up.    FWIW, Brian didn't seem concerned about it.

I thought that a significant dimension of the A370PEQ is that it has a certain amount of EQ built in.  It's difficult to imagine any non-perfect room with non-infinitely flexible ability to locate speakers and dampening elements to not require some form of EQ to balance the bass response to the tastes of the owner... noting that tastes sometimes change by musical genre or even mood.

I also had understood that the servo system lets a driver with a certain Q respond as though it had a much different Q.  Why is this situation fundamentally any different?

Assuming that a strong reduction in the Sd actually results in poor sound, where is the breaking/transition point?  As in, does the undesirable and not easily correctable behavior start happening when the enclosure opening is >120% Sd, 100% Sd, 80% Sd, 60% Sd... ? 

Are you willing to test to find out?  Again, the point is to see what degrees of freedom there might be for making GR OB products more accessible to potential customers for whom the current products aren't a fit.

Edit: rewrote % question for more clarity.

[Danny Richie]

If loaded this way then it will require a woofer with a lower Qts. This alignment will put a lot of pressure on the cones from this level of increased pressure. If you never drive them very hard it should be fine. You would also have to EQ out the peaked output this will cause. The servo amp will do that.

We do have a version of this speaker in development with three 8" servo subs that will maintain the smaller front area that your design offers.