[Beardy]

Been a while since I've been a regular here so I may have missed a solution already exists...  If so please point me in the right direction.

Am interested in a mid bass/musical OB sub to provide support to a Maggie.  To provide coverage down to ~25-30Hz and crossing to the Maggie at 100-150Hz or so with the capability to play to 500-1kHz to give some flexibility in the crossover tuning.  In short a DIY approach to the Magnepan UBS. 
I have a pair of servo dual subs which play with an OB MTM NX winged main and I am very happy with them but a, they are rather DIY looking (down to me...) and b, I'd like to retain a commercial planar to listen to occasionally as they are a very `polite' speaker that my wife appreciates.  Lastly, I'd also like to tackle this with lower mass non-servo conventional drivers with a long term option that I can go active and deal with the frequency management at line level.  I was thinking of a pair of line sources of ~6-10x 4-6" woofers.  My thinking is that an OB line source might match well with the Maggie and I should add that they don't need to play very loud.

Any thoughts?
thx

[Tyson]

HAL built out a quad of 8” servo woofers in a mini-line array, sounds close to what you are looking for.

[HAL]

Something like this?

Using the 4x8in servo subs from 30Hz to 160Hz with the Magnepan MG10/QR speakers.

[Beardy]

That certainly addresses my exact request!

If I didn't need these to go quite so deep, do you think this could be done with smaller drivers? I have half a mind to build an El-PipeO or two that could/would cover the lowest frequencies...  I'd really rather stay with some conventional (non-servo) drivers...

cheers

[HAL]

That is a question for Danny as it would be a new design.

[Beardy]

Perhaps I could rephrase...

An open baffle line array, maybe like a tall wedgie base, using several woofer drivers all of the same type (130 or 165?).
Can anyone guess at the performance?
One could put a wing on one side of the baffle and push the other side up against the Maggie to give some baffle extension.

I think at one point Danny may have mentioned using multiple LGKs below the Wedgie in a wedged U shaped open baffle as an option for lower frequencies.  It would be interesting to know what that could do. 

The need to support Maggies in the lower frequencies has been recognised for a long time.  An open Baffle line array seems an obvious option and there is a significant potential market
cheers

[Tyson]

You mean like the mid-bass sections of the NX series?

[Rocket_Ronny]

If you want to go smaller in size you could look at the Rythmik FM8s. While they are not open baffle, they don't need to be. I owned them for a month then bought a pair of GR Super Vs with the open baffle dual 12s woofers and ended up selling the Rythmiks, mistake.

Now that I sold the Super Vs, I am buying, like at this minute - they are in transit, another pair of FM8s. My plan with those was to use them as the bass section to play around with various mid/highs. So lets' say I did not know what the GR NX sound was like, I could get Danny's NX studio's and get a good feel for the house sound all the while having fast bass down to 20 hz.

Even though the FM8s are not open baffle, it's not a problem and will easily blend with planers. Think of these as the bass section for the Von Schweikert VR 55s that are 75k, or Joseph Audio Pearls, or Genesis Vs. They are fantastic subs that play up to 200 hz. Get the gloss black versions as they look beautiful. I will be building a 8-10" bass for them and placing on the FM8s a pair of GR Research Super Minis to start and messing around with other monitors later. I think if ever there was an end game speaker, the FM8s come as close as anything I have considered.

https://www.rythmikaudio.com/FM8.html

Having said all of that, I really do like what Hal is doing with the 8" woofers stacks. Those are an obvious choice if one wants to stay completely open baffle. They just don't work for me as I have to share our living room and I need a minimalist speaker system. That is what I sold the Super Vs.

Rocket Ronny

[Beardy]

@Tyson:  Yes.  exactly.  I went back and looked and Danny noted that the 4x 165s on the base section play well down to 60Hz (although all the measurements seem to have disappeared since I first looked).  As noted I have a hankering (just for grins), to play with a pair of 10ft organ pipe El-pipeOs for the lowest of the low. So 60Hz would be peachy.

However, for aesthetics... if I could get away with something with a narrower front baffle (thinking maybe 6x 130 drivers rather than 165), then it could sit right beside a Maggie.  Taking that idea further, IF it was stood alongside the base panel of a planer, then may be able to do away with the wing nearest the planar and have an L shaped footprint, like a wing on a Wedgie (as opposed to the angled U shaped baffle used on the NX bass section).

A lot of Magnepan owners state that the speakers are a little flexi and there is an aftermarket in stands and braces for these thin panel speakers.  So taking this idea further; A  tall line array that can be fixed (bolted, clamped or screwed), to the side and back of a planar to fill in the midbass AND brace the panel could be quite a useful and potentially popular DIY mod for panel owners, especially as it would leverage the credibility gained by the new Magnepan UBS offering.

@Rocket I really want to stay OB.

[g3rain1]

@Tyson:  Yes.  exactly.  I went back and looked and Danny noted that the 4x 165s on the base section play well down to 60Hz (although all the measurements seem to have disappeared since I first looked).  As noted I have a hankering (just for grins), to play with a pair of 10ft organ pipe El-pipeOs for the lowest of the low. So 60Hz would be peachy.

However, for aesthetics... if I could get away with something with a narrower front baffle (thinking maybe 6x 130 drivers rather than 165), then it could sit right beside a Maggie.  Taking that idea further, IF it was stood alongside the base panel of a planer, then may be able to do away with the wing nearest the planar and have an L shaped footprint, like a wing on a Wedgie (as opposed to the angled U shaped baffle used on the NX bass section).

I don't think just stacking a bunch of 5in drivers will get you what you want. Their identical responses will just add up giving you more sensitivity but the same roll-off point. You would probably have to low pass half the drivers to get the system to reach lower down. Or amp them separately with something that can shape the response.

[Rocket_Ronny]

@Rocket I really want to stay OB.

I understand what you are saying but I can tell you that the FM8s blend seamlessly with OB. I am an open baffle guy myself. You might even find the FM8s to offer tighter, more defined, bass than OB offerings. But you did not hear that from me, .

Rocket Ronny

[Danny Richie]

The easy way to get great results is to use the 8" or 12" open baffle servo subs. Those things will do anything that you want.

Trying to make it work with smaller non-servo woofers will be a real trick and will not yield results anywhere near as good as using the servo woofers.

[Beardy]

Hi Danny,

I have your MTM NX top section and a pair of the dual 12" servos.  I agree the servo subs would do what I'm asking. 

However, I think/hope that:
Multiple lower mass conventional woofers would enable me to play with the crossovers at line level and biamp in the future. 
It will also match with maggies more aesthetically (IMO).
Potentially could be a lower cost option.
I'm guessing that the propagation of the output from a line array might match better with the Maggie??

[Danny Richie]

To give it a shot you could make an L shaped baffle to butt up against the Maggie frame and then line it with some of our M-130 or M-165 woofers.

It will require some electronic crossover manipulation and separate amp to get them to work.

[Beardy]

I agree.