Jordan bass cabinets

[Colin]

As part of refitting the lounge, I have a shelf which will run below a bookcase, giving me the option of building a bass speaker into the room. (The shelf was once a platform so it is structurally solid.)

I'm intending to use one or more Jordan JX125s (I have four) and the space available gives me the option of 2 units in a MLTL (GM's design from the Jordan site ) or a single unit in a BIB.

The aim is to have something which will be rolled off above 80-100Hz (depending on the main speakers used). I am a little cautious as I don't like bass which booms and it's a corner position. The MLTL seems tunable and could be built with the port away from the corner. The BIB would, of course, be floor loaded rather than ceiling.

Sketch attached. The blue box is the shelf (it's long enough for two MLTLs but s*d's law, the lounge layout is fixed by the staircase - the grey box). Red boxes are the main LS positions, fetching green box is the listening position. Room size is 19 x 12 feet and all timber/stud wall construction.

Any input from GM and the BIB-sters greatly appreciated.

 

[GM]

Greets!

Hmm, what's between the mains? Subs along just one side wall would probably have to be XO'd extremely low/steep to keep from being obviously weighted to one side. Having its parallel wall so far away from the listening position just aggravates the problem.

GM

 

[Colin]

Hi - Not the ideal layout, I agree. There's nothing between the mains and I anticipate using just one end of the shelf for the bass unit, to keep it close to the main units (the line shows where the cabinet can be divided). The CSA is enough to use 2 drivers per MLTL.

I have experimented with a stand alone sub placed to one side and up to 80Hz or so I didn't notice any problems. That was a while ago though and not with this exact layout.

The mains will be one of the JX92 MLTLs. I've yet to try the shorter version so the idea of a bass cabinet is to give some flexibility for the future (and building it in before it get colonised by books, cupboards or other inessentials apparently required for domestic harmony).

 

[GM]

What about a pair of folded JX125 ML-horns laid on their sides to make a 'stereo' platform to perch the short MLTLs/whatever on?

 

[Colin]

I'd be better trying to put the mains over the existing shelf.

The wall behind the mains backs onto a void, so in theory I could use that. There isn't room for enclosures (there are services tucked away in there) but it would make an IB (there is 2k5 litres).

 

[GM]

OK, the 125 has too little Xmax for an IB even with four and some room loading for best performance. This layout is much better IMO, allowing corner loading in both channels of pipe horns/whatever, but the cavity will need some serious, yet easily removable, damping. Due to this it may be better to lay them along the side walls, increasing WAF shelf space .

GM

 

[Colin]

Okay, I'll work on that and see about building smaller main units to go above the existing shelf. I assume, to allow a higher pass to the mains, the 'driver end' of the MLTLs should be on the outside, with the ports central.

 

[Colin]

As in ...

 

[GM]

As in sofa facing existing shelf with the mains either upright or laying down on it depending on how tall it is and the two subs where the mains and sofa currently are.

 

[Colin]

Ah, got you. Thanks for the input, as always. My last diagram would have made more sense if I'd moved the red boxes to sit over the shelf - but I see what you mean wrt the wall positions for two separate MLTLs.

It's an awkward room and the staircase precludes moving the sofa. I have the use of a small sub at the moment, so I'll move it around and test various arrangements.

The desire to hide much of the bulk of speakers is less about WAF than DOOF (dog/owner obstacle factor).

 

[GM]

OK, is ceiling/wall juncture mounting an option?

 

[Colin]

We-e-ll, there's a fifteen foot high loft ... (anyone about to suggest a horn - don't). I wouldn't contemplate cabinets in the room near the ceiling, I think it would be better to find drivers better suited to IB use and build a manifold in the loft.