[SlushPuppy]

I'm picking-up my Magnepan 1.7's from the dealer tomorrow and am having difficulty choosing a sub for a stereo only system. It will be a few weeks before I place the order, as I need to get some things ironed-out in the room first, but I'd like some input from the board to help with my decision.

The two subs I'm considering are the Rhythmik D15SE (sold by Ascend Acoustics) and a DIY OB sub using two SW-12-16FR drivers (sold by GR Research).

All I want to do is fill-in the bottom end of the 1.7's and am looking for a sub that will blend-in and not call attention to itself. I couldn't get my SVS PB-13 Ultra to blend with anything, so I sold it last week to fund this purchase.

Any ideas or comments?

Thanks!

[HAL]

I think Danny Richie is working on 8" open baffle Rythmik servo's for 1.7's soon.  IIRC he was looking for a pair to mod.

You might ask him.

[SlushPuppy]

I think Danny Richie is working on 8" open baffle Rythmik servo's for 1.7's soon.  IIRC he was looking for a pair to mod.

You might ask him.

I saw that thread, and those would be my first choice, but I don't know where the cost is headed and I've been given a budget that I can't exceed    I'm just looking for the best fallback if those aren't doable. If they're within my budget it's a no-brainer.

[josh358]

I think I'd try the OB. They probably won't play as hard, but they'll be a better match and give you some dipole advantages, such as triggering fewer bass modes and relative freedom from box resonances.

That being said, small servo subs are usually a good match.

[SlushPuppy]

I think I'd try the OB. They probably won't play as hard, but they'll be a better match and give you some dipole advantages, such as triggering fewer bass modes and relative freedom from box resonances.

That being said, small servo subs are usually a good match.

Thanks Josh.

I'm done with the special effects stuff, so a musical low end is all that's necessary. My room had problems with the big SVS in both ported and sealed modes. Large nulls that I could only partially work-out by having the sub in a not so great location. OB subs seem to eliminate a lot of the bass loading and might work better in problem rooms like mine.


Thanks,

Dave

[THROWBACK]

The GR Research OB servo 12's work fantastic with my Soundlabs. In fact, having tried about six different closed box and ported subs, the GR was the only one with the same dipole pattern as my ESL's. Danny is freat to work with, and the cabinets are duck soup to build.
Best wishes,
Chuck

[josh358]

Thanks Josh.

I'm done with the special effects stuff, so a musical low end is all that's necessary. My room had problems with the big SVS in both ported and sealed modes. Large nulls that I could only partially work-out by having the sub in a not so great location. OB subs seem to eliminate a lot of the bass loading and might work better in problem rooms like mine.


Thanks,

Dave

Open baffle subs should much reduce both the main vertical and lateral modes, so you can focus on the z axis. They also partly cancel the z-axis mode, if they're about the same distance from the front wall as you are from the rear wall, because the front wall reflection of the out-of-phase backwave reaches your ears at the same time as the rear wall reflection of the front wave, cancelling it. But I think this is more effective with line sources.

BTW, the Germans have a cool plane wave system which uses woofer arrays on the front and back walls. The front array sends a plane wave through the room, and then, when it reaches the back wall, a delayed, inverted signal is sent to the rear array to cancel it. There are no reflections or room modes at all! The only disadvantage (other than having to buy eight woofers) is that you can only match levels at one distance, since the planars fall off at 1/R but the woofer array doesn't fall off at all, the side, floor, and ceiling reflections make the array act like an infinite plane so the bass is at the same level everywhere in the room. I imagine it sounds amazing.

[SlushPuppy]

The GR Research OB servo 12's work fantastic with my Soundlabs. In fact, having tried about six different closed box and ported subs, the GR was the only one with the same dipole pattern as my ESL's. Danny is freat to work with, and the cabinets are duck soup to build.
Best wishes,
Chuck

Thanks Chuck,

That's the kind of info I was looking for. I look forward to finally owning one of Danny's products.


Dave

[SlushPuppy]

Open baffle subs should much reduce both the main vertical and lateral modes, so you can focus on the z axis. They also partly cancel the z-axis mode, if they're about the same distance from the front wall as you are from the rear wall, because the front wall reflection of the out-of-phase backwave reaches your ears at the same time as the rear wall reflection of the front wave, cancelling it. But I think this is more effective with line sources.

BTW, the Germans have a cool plane wave system which uses woofer arrays on the front and back walls. The front array sends a plane wave through the room, and then, when it reaches the back wall, a delayed, inverted signal is sent to the rear array to cancel it. There are no reflections or room modes at all! The only disadvantage (other than having to buy eight woofers) is that you can only match levels at one distance, since the planars fall off at 1/R but the woofer array doesn't fall off at all, the side, floor, and ceiling reflections make the array act like an infinite plane so the bass is at the same level everywhere in the room. I imagine it sounds amazing.

Here's the story with my SVS - when I was listening to music or watching a movie I could feel the bass coming out of it, but couldn't hear it too well at my listening position. Walk out of the room and stuff was rattling all over the place and you could hear every damn note. I saw some of Danny's feedback on the Super V bass system and thought that OB subs might eliminate a lot of the problems I've been having. Looks like there are more advantages to OB bass than I thought.

Thanks guys, I think the next step is contacting Danny after the holiday rush 


Dave

 

[rw@cn]

Here's the story with my SVS - when I was listening to music or watching a movie I could feel the bass coming out of it, but couldn't hear it too well at my listening position. Walk out of the room and stuff was rattling all over the place and you could hear every damn note. I saw some of Danny's feedback on the Super V bass system and thought that OB subs might eliminate a lot of the problems I've been having. Looks like there are more advantages to OB bass than I thought.

Thanks guys, I think the next step is contacting Danny after the holiday rush 


Dave

Did you check your phase?

[SlushPuppy]

Did you check your phase?

Yeah, I made every adjustment you could possibly make. If I fixed one problem I created another. Frustrating. That sub just didn't work in my room. Looking back I think two of their smaller subs would have been better, but I'm going in a different direction now.

[SteveFord]

If the direction you go in doesn't work out try adding a DMW or two. 
They won't go lower than your 1.7s but can bring about a 3D effect if you experiment with placement.

[TitaniumTroy]

I have an SVS PB Ultra 2, have it crossed over at 40hz. I also have a lot of bass traps in the room at the corner's, seems to work for me.