[squeedle]

Hey gang! I am really intrigued by the GR open baffle subs, but have a bunch of general/vague questions. Would love to hear you folks weigh in if you have any strong feelings or firsthand experiences to share! Here are some of the types of questions I have in mind...

1) Are OB subs ideally paired with OB mains? Or do they pair well with any speaker? (I currently have Vandersteen 2's.)

2) For traditional subs, conventional wisdom is to have 2 or more of them to aid in smooth coverage across multiple listening areas. Does this also apply to OB subs? If so, could I have 2 single-driver OB subs? Or does it have to be 2 dual-driver OB subs? GR's web site seems to imply that only the 2- or 3-driver versions are available in OB configuration--I'm not sure why. Each 2-driver OB kit is about $1500 and that is just for raw unfinished parts. Getting two of those is over $3k, way more than I ever thought of spending on subs.

3) Is there any performance concern with having the GR OB subs laid horizontally instead of vertically?

4) If you've heard both good traditional subs and OB subs, how do you feel they compare? Is OB worth the (to me) drastic price premium?

Thanks for any feedback you can share!

[subsonic1050]

I have a pair of triple servo subs, and before that I had a pair of Paradigm Defiance X15 subs. The GR open baffle subs blow the paradigms out of the water when it comes to speed, detail, texture, etc. Also they don't load the room the same way and are more enjoyable for music. Once I had them I'd never be able to go back. I've never heard the doubles or singles, but I believe GR sells a single servo subwoofer kit, it just isn't available right now. I belive it is a lack of the rhythmik amp for the single sub that is the reason the single is unavailable at the moment.

[Hobbsmeerkat]

We do have cheaper versions of both Servo Sub kit 2 & 4
But we haven't been able to get the new HX amps for to bring back the Kit 1 & Kit 3.

You can still get a single-sealed sub kit 2 that uses the larger A370 amp. It's faster than most any typical sealed amp, but not as good as any of the OB offerings, tbh.

[squeedle]

Thanks for the replies. So maybe a single OB kit will become available at some point? That would be a no brainer for me.

Hobbsmeerkat, do you have a web site? Where can I see your pricing and options? Thanks.

[NoahH]

https://www.gr-research.com/

[Hobbsmeerkat]

A single OB sub isnt really a viable solution, it really needs to be 2 or more to work as intended.
You're better off getting a sealed sub if you're tight on space.

But if you really want OB but are only moderately limited on space  you can lay a dual sub onto it's side in the middle of your setup without issue.

[squeedle]

That kind of gets back to my question about whether OB subs need to be run in sets of 2 or more, same as ported/sealed subs do. Yes I could lay one OB sub on its side, but would that have the same positive effects as 2+ traditional subs--meaning cancelling out room nulls, etc. ? It's not really space that's at such a premium, it's money.

[mlundy57]

That kind of gets back to my question about whether OB subs need to be run in sets of 2 or more, same as ported/sealed subs do. Yes I could lay one OB sub on its side, but would that have the same positive effects as 2+ traditional subs--meaning cancelling out room nulls, etc. ? It's not really space that's at such a premium, it's money.

Hobs is talking about the number of OB drivers per cabinet driven by one amp. Two OB drivers per cabinet and amp are the minimum. It has to do with the parameters of the OB drivers and amp which are different than the driver and amp used in a sealed box. And no, you cant use two separate cabinets in different locations with the same amp. This has to do with the way the servo circuit works.

If budget is an issue, start with one or two sealed servo subs. If later on you want to go with OB when the budget allows you can.

Remember, OB speakers, including subs need to be a minimum of 3ft from the front wall. They can be close to side walls because their radiation pattern has nulls to the side.

Regardless of whether you build sealed or OB subs, go with the A370 series amp(s). They have more connectivity options and are way more configurable than than HX series amps. This allows the A370 amps to be dialed into the room better than the HX amps. The downside of all the flexibility is complexity, but the results are worth taking the time to get it dialed in.

[squeedle]

Thanks, it does get difficult to word things clearly here. Apologies for that.

With traditional subs, the recommendation is generally to have 2+ enclosures per room. That way they can be spaced far apart from each other to help minimize room modes/nulls.

So my question is: how does a single OB sub enclosure (whether with 2 drivers or more) compare to having multiple single-driver traditional subs? Does the OB nature of it negate/lessen the need to have multiple enclosures? Or does one still need to have 2+ OB enclosures to get the same type of room coverage as with 2+ traditional sub enclosures?

Also, Rythmik doesn't seem to offer any subs with the SW-12-16FR driver that GR sells for their OB sub kits. (Rythmik only sells the 8 ohm version, not the 16.) So I wouldn't be able to upgrade any of their offerings to the GR OB format down the line without buying all new drivers. Right?

Thanks for the reply and notes on the A370 amp.

[Tyson]

OB is not like traditional subs.  OB subs don't excite room modes in the same way that box subs do.  So with box subs you are better off using multiple subs dispersed around the room, but with OB subs they work best as a pair and located as close to the main speakers as possible.  They also need to be 3 feet out in to the room.

If you can't do a pair of OB subs immediately, then a good alternative is a single OB sub directly between your main speakers.  Again, 3 feet from the wall, minimum.

[squeedle]

Thanks, that was what I really needed to know!

[Vince in TX]

While I was building my OB speakers, I was running a pair of SVS SB-2000 Pro subs at the front of the theater.   And they were okay since that's what I've been used to hearing the last 10-15 years or so (single ported or dual sealed SVS subs).   This theater room was my first venture into OB.

Before:



After:



Let me tell you, the difference in sound is night and day.   I invited my nephews to stay the night over the weekend because they hadn't seen Fast 9 yet.   When I first screened it for friends a while back, I was still running the SVS subs.   This was the first movie I've screened for others since dialing in the OB subs and pairing the system with the A/V-1RS surround speakers (I still have one of those SVS subs in the room except it's at the back on a 180 degree polarity shift now).   I sat in the back-right seating position since I had already watched it and let my oldest nephew sit front row center (ideal listening position).   The experience even in that back row offset to the right was more incredible than front row center was with the SVS subs.   It's hard to describe.   One sequence even gave me goosebumps because the music tracks sounded so good.

The second movie we watched was Interstellar.   My oldest nephew is taking astronomy, and they'd been trying to watch it in class but couldn't finish it for some reason or another, so we fired it up.   I also have soundshakers in the seats that activate below 50Hz, and this movie has a whole lot of LFE in it.   When they launched the ship, the experience was so immersive between the soundshakers and the speaker system that it literally felt like we were onboard that ship.   The feeling was exhilarating.  Every sound coming out of the speakers was so incredibly realistic that it's like nothing I've ever experienced before outside of an IMAX theater.

Highly recommended.   

[squeedle]

Awesome! I'm really looking forward to hearing these!

[Vince in TX]

Awesome! I'm really looking forward to hearing these!

One thing to note (and you can see it in the photos I posted) is room treatments.   Every little thing I did to treat the room made incrementally better sound overall.   I'm still waiting on some QRD diffusers to finish it up, but the bass traps were worth every penny.

[squeedle]

Yeah that's still a bit over my head. I just ordered a MiniDSP + mic and will be giving REW a try for the first time later this week. Baby steps.