I'd use dry coarse sand, crushed glass "sand" blasting media, or "lead" shot" in the voids. It'll help damp resonances somewhat, and in the lower void will improve stability as well.
While it might detract somewhat from the aesthetics, I think you'd achieve more benefit from in a small internal brace in the mouth ( i.e. 3/4" x 3-4" strip of ply or even solid hardwood), oriented at an angle
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There's no such thing as too rigid/massive a BLH, only a point of diminishing returns and the smaller the cab, the more added weight typically required, so lead filled wouldn't be too extreme, but sterilized sand, Portland cement or similar will work quite well. Doubling all exterior panels or at least the mouth, base area is a good plan also.
Last, but not least, mass loading it to the floor usually is worth the cost/effort, so adding weight to the top and a wider base to compensate typically yields the most obvious tonal change, though if in an upstairs apt. or bedroom, then of course probably not a good plan.
Not to put too fine a point on it though, some folk's hearing can't tell enough sonic difference to justify the material/labor cost, so clamping some scrap on to test first is what I'd do.
Anyway, please let us know what, if any, changes you make and what you think of them.
GM
Last, but not least, mass loading it to the floor usually is worth the cost/effort, so adding weight to the top and a wider base to compensate typically yields the most obvious tonal change, though if in an upstairs apt. or bedroom, then of course probably not a good plan.
Not to put too fine a point on it though, some folk's hearing can't tell enough sonic difference to justify the material/labor cost, so clamping some scrap on to test first is what I'd do.
Anyway, please let us know what, if any, changes you make and what you think of them.
GM
Sounds reasonable.
I have used sand in the bottom of a pair of 108ez BiB's before (I extended the cabinet height to get the Driver to ear level, then filled the void below the false bottom with sand.
I have used Lead Shot extensively before in the past to fill stands for small 2-way speakers (LS35A, SL-6 etc)
I'll add some weight to the voids and put the cabinets together.
I'll then experiment with a brace in the mouth and reinforcing the sides and back externally.
Has anybody tried dampening foam or rubber inside the mouth ?
I have used sand in the bottom of a pair of 108ez BiB's before (I extended the cabinet height to get the Driver to ear level, then filled the void below the false bottom with sand.
I have used Lead Shot extensively before in the past to fill stands for small 2-way speakers (LS35A, SL-6 etc)
I'll add some weight to the voids and put the cabinets together.
I'll then experiment with a brace in the mouth and reinforcing the sides and back externally.
Has anybody tried dampening foam or rubber inside the mouth ?
Portions as required with the mouth always needing at least one on each opposing sides in the few forward firing BLHs I've experimented with, i.e. for your horns, one side wall and the bottom section between the slanted board and mouth. Note that you don't want it go all the way to the corners, so only about ~0.7x the span/2.
The object is to clean up some of the overlapping HF through the acoustic XO BW, so when experimenting, try to limit its output to an octave or so on either side or at least listen [preferably a relatively youthful female] to a female solo with no music and when it gets as clear/'tight' as it can without obviously hearing a dip in the response, that's as good as it gets.
GM
The object is to clean up some of the overlapping HF through the acoustic XO BW, so when experimenting, try to limit its output to an octave or so on either side or at least listen [preferably a relatively youthful female] to a female solo with no music and when it gets as clear/'tight' as it can without obviously hearing a dip in the response, that's as good as it gets.
GM
So I completed the BK12's over the weekend.
I addded Duct Seal to the 2 smaller voids in the top, and a small bit of duct seal, and about 20 lbs of lead shot to the larger voids in the bottom of the cabinet.
I currently do NOT have spikes yet installed, and the current location of the speakers is not in corners of a room, so my disapointment in the lack of bass may be relieved. Initial listening impressions are good, but currently not able to make a "full review" as I'm just using a cheap CD player and Solid State Amp, through a Proceed Pre Amp, and the the above mentioned installation.
Not sure they will ever be a match for my 108EZ BiB's. But the much lower height is why I built them as i want to put them in by the pool table, and I needed something that the butt of the pool cues would pass over. I have also purchased the wire grills to be install over the FE126en's, to protect the driver from the cue butt, once they are placed near the pol table.
I addded Duct Seal to the 2 smaller voids in the top, and a small bit of duct seal, and about 20 lbs of lead shot to the larger voids in the bottom of the cabinet.
I currently do NOT have spikes yet installed, and the current location of the speakers is not in corners of a room, so my disapointment in the lack of bass may be relieved. Initial listening impressions are good, but currently not able to make a "full review" as I'm just using a cheap CD player and Solid State Amp, through a Proceed Pre Amp, and the the above mentioned installation.
Not sure they will ever be a match for my 108EZ BiB's. But the much lower height is why I built them as i want to put them in by the pool table, and I needed something that the butt of the pool cues would pass over. I have also purchased the wire grills to be install over the FE126en's, to protect the driver from the cue butt, once they are placed near the pol table.
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Are you implying that putting something under the speakers will improve the bass?
Not deeper, but better defined, tighter !
Check post #53 of this thread for some nice inexpensive options.
Also, the spikes give some leveling adjustment and look nice, can even tilt the speakers back a bit if wanted, but the primary purpose is sonic.
I have always found some type of spike or cone sonically benificial in imaging and better defined bass, in 2 way systems the tilting back can get the tweeter behind the woofer.
Check post #53 of this thread for some nice inexpensive options.
Also, the spikes give some leveling adjustment and look nice, can even tilt the speakers back a bit if wanted, but the primary purpose is sonic.
I have always found some type of spike or cone sonically benificial in imaging and better defined bass, in 2 way systems the tilting back can get the tweeter behind the woofer.
on enclosures as narrow as these, FH3, Pensil7 & various other MLTL for 4" and under drivers, the increased stability of outrigger bars fit with adjustable feet can't hurt
in the case of the BK12, lifting the front a net of approx 1.3" will yield a 5dg tilt angle of front baffle and put the direct on axis line at approx 1 meter at listening distance of 3 meters - I've found this arrangement works well at improving soundstage height of shorter enclosures such as the BK12, HornShoppe Horns, Buschorn MK I etc.
look for bass extension "weight" to improve significantly, and to a lesser degree, dynamics and micro-detail
bk-12
just finished a set of bk-12. duct compound'ed the basket frame, and made a set of outriggers with spikes. deff want to get them on some cheap slabs of granite, think it will help for some extra base. sounding better ever day. going to give these 50$$ a good break in, then rip them a new *******!!!! love the birch wood with just tung oil and some steel wool. ed
just finished a set of bk-12. duct compound'ed the basket frame, and made a set of outriggers with spikes. deff want to get them on some cheap slabs of granite, think it will help for some extra base. sounding better ever day. going to give these 50$$ a good break in, then rip them a new *******!!!! love the birch wood with just tung oil and some steel wool. ed
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that idea's been patented in SC already, IINM - don't make the honey badger chase y'all down
Somewhere in the FH3 threads is a visualizarion of that config for 4 merged FH3.
dave