GR Reseach Open Baffle Servo Subs

bdp24 · « **Reply #20 on:** 10 Feb 2015, 03:52 am »

Music lovers who chose panel speakers (electrostatic, magnetic planar, or ribbon---I have all three) because of their ability to make music sound more real than any box speaker, have for decades had to choose between disconnected, bloated deep bass, and no deep bass at all. The fact that there is now a woofer system (the GR Research/Rythmik OB Servo) that is good enough for use with the best (but deep bass-shy) speakers in the world is a huge deal. I'm so happy I managed to live long enough to now be able to hear reproduced music as never before. Excuse me, I have to play some more music!

Hank · « **Reply #21 on:** 10 Feb 2015, 05:41 pm »

Good for you! I plan to build servo sub to keep up with my Acoustat Model 3's - just need to decide on either three 8's or two 12's.

Tyson · « **Reply #22 on:** 10 Feb 2015, 06:06 pm »

3 x 8 cones have a surface area of 150 inches, while 2 x 12 have a surface area of 226 inches. In bass, particularly OB bass, this matters. I'd go with the 2 x 12 if at all possible.

bdp24 · « **Reply #23 on:** 10 Feb 2015, 10:43 pm »

Or three 12's!

Tyson · « **Reply #24 on:** 10 Feb 2015, 10:44 pm »

Quote from: bdp24 on 10 Feb 2015, 10:43 pm

Or three 12's!

More is always better. I wonder if one could do a line source - maybe 6 or 9 of the 12 inch subs stacked floor to ceiling. Might be very interesting to hear.

mlundy57 · « **Reply #25 on:** 10 Feb 2015, 11:17 pm »

WHATT???????

Outofthewoods · « **Reply #26 on:** 10 Feb 2015, 11:25 pm »

Why not make it a complete package?!

Ruben

S Clark · « **Reply #27 on:** 10 Feb 2015, 11:55 pm »

That model is still on the drawing boards, isn't it? Next time I've got about $50 000 loose in my pocket, I'm calling Danny and ordering a pair.

Outofthewoods · « **Reply #28 on:** 11 Feb 2015, 12:02 am »

Quote from: S Clark on 10 Feb 2015, 11:55 pm

Next time I've got about $50 000 loose in my pocket, I'm calling Danny and ordering a pair.

You've had $50,000 loose in your pocket?!!!

Ruben

HAL · « **Reply #29 on:** 11 Feb 2015, 12:28 am »

Scott,
The Singularity was more like $150000 in that cabinet.

HAL · « **Reply #30 on:** 11 Feb 2015, 12:30 am »

Ruben is working on an idea for me. Interlocking 2x12" stackable OB H frames. Want to build two 6x12 OB arrays with the HX800 amps.

I am dreaming BIG!

Outofthewoods · « **Reply #31 on:** 11 Feb 2015, 12:57 am »

Quote from: HAL on 11 Feb 2015, 12:30 am

Ruben is working on an idea for me. Interlocking 2x12" stackable OB H frames. Want to build two 6x12 OB arrays with the HX800 amps.

I am dreaming BIG!

Hey Rich,

Want me to build it so that you can add another (3) modular subs in the future?

Ruben

HAL · « **Reply #32 on:** 11 Feb 2015, 01:00 am »

Ruben,
I will probably do structural damage with 12-12". It is tempting though!

Outofthewoods · « **Reply #33 on:** 11 Feb 2015, 01:03 am »

Quote from: HAL on 11 Feb 2015, 01:00 am

Ruben,
I will probably do structural damage with 12-12". It is tempting though!

Hank · « **Reply #34 on:** 11 Feb 2015, 05:35 pm »

You guys are nuts.

When I win the Texas lottery, I'll explore the Singularity.

I was leaning toward two 12's, so that'll probably be what I replace my 15" driver sonosub with.

Tyson · « **Reply #35 on:** 11 Feb 2015, 06:29 pm »

I wonder why Rythmik/GR don't offer 15 inch servo subs? A 12 inch driver has a surface area of 113 inches, a 15 has 176. So if you are doing a pair of drivers, the 12 inchers would have 226 total area, the 15's would have 352 inches, a substantial difference. Only thing I can think of as a possible reason - a pair of 12's makes for the perfect height for the bottom of a speaker, while a pair of 15's would be too tall.

rollo · « **Reply #36 on:** 11 Feb 2015, 07:52 pm »

Well me as well. Have been fooling myself with other subs wit my Pipedreams. Saving my pennies.

charles

mojave · « **Reply #37 on:** 11 Feb 2015, 07:58 pm »

Quote from: Tyson on 11 Feb 2015, 06:29 pm

I wonder why Rythmik/GR don't offer 15 inch servo subs? A 12 inch driver has a surface area of 113 inches, a 15 has 176. So if you are doing a pair of drivers, the 12 inchers would have 226 total area, the 15's would have 352 inches, a substantial difference. Only thing I can think of as a possible reason - a pair of 12's makes for the perfect height for the bottom of a speaker, while a pair of 15's would be too tall.

Rythmik has had 15" servo subs for years. Or are you talking about a 15" servo driver with a paper cone like the GR-Research servo drivers?

Your total area is way off. The spec for area of the driver diaphragm is Sd and is 480 sq cm for the GR-Research 12" driver which equates to 75.9 sq in. The 15" driver is 125.4 square inches. However, displacement is a more accurate way of comparing drivers and takes into account x-max. Displacement is the total volume of air that a subwoofer driver is capable of moving and is typically compared using liters. You multiply the peak to peak x-max by the Sd. Since

The Rythmik 12" driver has a displacement of 1.6 liters. The Rythmik 15" driver has a displacement of 2.4 liters. However, some 15" drivers have a displacement of over 4.59 liters and others just have .955 liters. The main issue is that two 12" dual opposed drivers can be used in about the same volume of box as a single 15" driver. This nets you greater output per box size.

baniels' new pair of 24" subwoofers have a total displacement of 30.66 liters! That is equivalent to slightly over 19 GR-Research 12" drivers.

Danny Richie · « **Reply #38 on:** 11 Feb 2015, 08:10 pm »

Quote from: Tyson on 11 Feb 2015, 06:29 pm

I wonder why Rythmik/GR don't offer 15 inch servo subs? A 12 inch driver has a surface area of 113 inches, a 15 has 176. So if you are doing a pair of drivers, the 12 inchers would have 226 total area, the 15's would have 352 inches, a substantial difference. Only thing I can think of as a possible reason - a pair of 12's makes for the perfect height for the bottom of a speaker, while a pair of 15's would be too tall.

I look at this only from an audiophile standpoint. You don't gain anything. You just loose performance. The moving mass of the 12 is much lower and offers better control and stopping ability. The 15 doesn't play any lower. It just adds moving mass and less control.

If you need to move more air than one 12 then use two.

Tyson · « **Reply #39 on:** 11 Feb 2015, 08:21 pm »

Quote from: Danny Richie on 11 Feb 2015, 08:10 pm

I look at this only from an audiophile standpoint. You don't gain anything. You just loose performance. The moving mass of the 12 is much lower and offers better control and stopping ability. The 15 doesn't play any lower. It just adds moving mass and less control.

If you need to move more air than one 12 then use two.

Makes sense. Plus, based on my own experience, a lot of guys that are using drivers with large surface area and huge swept volume are looking to pressurize the room, and you can't do that fully without a lot of air being swept/moved.

On the other hand, the true benefit of OB subs is that they DO NOT pressurize the room. So you never get that "swimming under water" feeling at all. But that's kind of the point! OB bass gives you clarity and detail to a FAR greater degree than any monopole sub ever can (any OB sub that's decent, not just the GR subs). What you give up, normally, is impact and slam when you move to an OB solution. At least until you add the Servo control to the equation. Imagine the kick and slam you get from a box sub married to the clarity and detail you get from a traditional OB sub and you've got a pretty good idea of what makes the GR/Rythmik solution so special. As I said previously, sometimes things are just flat out better. This is one of those cases.