Do I seem a tad obsessive? 
~ I’m a mid aged man late to the great audio diy "game", with a confluence of little building time, very limited building skills, very high aspirations, and a wish to ascend to the summit (or two) with minimal “mistakes”
Obsessive yes, but hey, the R&D is part of the journey & balance from the tedium of everyday life
Cheers
~ I’m a mid aged man late to the great audio diy "game", with a confluence of little building time, very limited building skills, very high aspirations, and a wish to ascend to the summit (or two) with minimal “mistakes”
Obsessive yes, but hey, the R&D is part of the journey & balance from the tedium of everyday life
Cheers
rick57 said:
Greets!
True, but the EBS has more gain in the BW above Fb.
Well, if you ignore the various system's Qs like most folks and many consumer manufacturers do, then your way if fine.
Think about it, if you start with a low Q driver and put it in a typical vented alignment the cab BW is considerably higher Q than the driver, so you want the cab roll-off to be more gradual to Fb, which means a TL size vent if the cab's Vb isn't increased. Unfortunately, drivers like the 2035HPL are optimized for small prosound sealed or BR cabs, so even in an EBS alignment the vent is pretty big, ergo a max flat impedance TL makes more sense to me, we'll just skip box and cram it in the 'vent'!
Very 'wrongly'! It's a slightly less well damped T/S max flat alignment and its large vent system adds considerable harmonic distortion, though some folks find it 'euphonic' while others that don't either block off some of the vents or stuff them with some type of damping material.
Pro sound compression or BLHs (aka scoop bins) are the 'slam'/'punch' champions, though for home use I prefer the Altec A7 style, but some folks prefer tractrix flares to the traditional expo, ergo the front horn will have to be larger to get the same gain BW.
GM
Hi GM, I sold off my Altec A7 system and bought the Edgarhorns. I thought the 350hz tratrix sounded great and in some ways better than the altec 1505s, but the Edgar 80hz bottoms totally lack the thump and slam I was use to in the A7s. I am going to FL in the morning to pick up my Dad and drive him home, but when I get back I am going to disasemmble my KLH subwoofer and build the Tapped with its components. Nothing like a fanciful experiment. Cheers.
hey djn - a k-coupler might ? give you the slam - if they're tiny like X15 and "khyboe" then will not have any bottom but "hit" is good - might take scrounging up some 15" with decent motor plus 10 cents worth of pvc
K15 or ~ 8 cubic foot with strong 18 have some low end
27.75x13.75x19.25" x15 copy coupler
myterious & pretty (not mine) KHYBOE type with beautiful chromed Transylvania Power "The Tube"
115BK is probably close to these and I've drawn the rough plan
115BK plan side view (external width ~20.5") - note theres barely enough room for an EV15L (kind without silly heatsink)
http://img490.imageshack.us/img490/5278/115bksidekp5.jpg
Do the wings look radial - or slightly modified on these?
K15 or ~ 8 cubic foot with strong 18 have some low end
27.75x13.75x19.25" x15 copy coupler
An externally hosted image should be here but it was not working when we last tested it.
myterious & pretty (not mine) KHYBOE type with beautiful chromed Transylvania Power "The Tube"
115BK is probably close to these and I've drawn the rough plan
115BK plan side view (external width ~20.5") - note theres barely enough room for an EV15L (kind without silly heatsink)
http://img490.imageshack.us/img490/5278/115bksidekp5.jpg
Do the wings look radial - or slightly modified on these?
An externally hosted image should be here but it was not working when we last tested it.
rick57 said:
Greets!
You're welcome!
Well, there's underdamped 'slam', the most common type, then there's built in acoustic gain, like you get from resonant loading, like BLH, etc..
Uncompressed dynamics defines 'slam', but unfortunately all consumer recordings are compressed to a greater or lesser extent, so to go ~live' requires some form of EQ and few drivers can handle the power required to reproduce a bass drum hit, so this only leaves some form of acoustic gain.
If the alignment didn't matter, I wouldn't be wasting my time responding.
The 2035 should be fine for a scoop bin, ask for recommendations on the Lansing forum if you want more upper mid-bass 'slam' than my DIY suggestion below: http://audioheritage.org/vbulletin/index.php
Peaking around 80 Hz is fine, but 1.5 dB won't even account for baffle step, which will probably 3-4 dB, much less any 'slam' gain. Then there's how the room will affect it, so no, a 1.6 dB peak/81 Hz probably isn't going to cut it.
The bigger cab's steeper roll off was below Fb though, we're concerned with the roll-off above Fb.
Anyway, as much as I like to 'bench race' audio, I need to move on to other commitments and IMO you need to either build/experiment to see what suits you or buy Edgarhorns or similar. If you want to experiment, then you need build only one cab for the JBL if the specs you posted are reasonably accurate:
L = 31.375"
CSA = 640"^2 (suggest 32.187" w x 19.875" d)
driver at extreme top
vent at extreme bottom with a 640"^2 area, so full width x 19.875" high
Use no-void plywood such as 19 mm 13 ply Baltic Birch with adequate bracing. BW limit it with whatever XOs you plan to use and start with it completely undamped except for some 1" acoustic fiberglass on one side, top, and back just in the area around the driver and if it's too...... whatever, then start adding more damping either till you're satisfied or if you conclude you can't stuff it enough, then start reducing the vent area/yanking out stuffing to suit. Then connect the mids/HF up and adjust levels, XO point/slopes as necessary and roll in the subs to suit.
Note that it's best to do all this with it placed in the desired in-room position and that you do the other one the same way since the room and other speaker will affect its performance and why stereo pairs typically isn't a good plan unless positioned well away from any boundaries and relatively close to the listening position.
After all this talk spread over the last year or so on several forums I expect a comprehensive report on whichever way you go.
Have fun on your journey, I did many decades ago!
GM
Half space sim of undamped cab:
Attachments
hi GM - sure did - and asked a party if certain estimates might work but answer was "no" and = cut and try.....
here's q quick 2035H sim in AJ for long vent reflex- what did U do above to peak it that loud? Freddy
http://img86.imageshack.us/img86/8862/quick2035ro8.jpg
ps - I've not had pleasure of MJK"s propgrams
here's q quick 2035H sim in AJ for long vent reflex- what did U do above to peak it that loud? Freddy
http://img86.imageshack.us/img86/8862/quick2035ro8.jpg
ps - I've not had pleasure of MJK"s propgrams
djn said:
Greets!
Interesting, I haven't auditioned any Edgar systems, just read many rave reviews. Yeah, in some ways tractrix is better, but I found conical to best them all, though they are much bigger for a given gain BW.
Do you have specs on the KLH or just hoping you're not wasting time/$$?
GM
freddi said:
Greets!
Please PM me with details.
Didn't do anything special, just a large, simple reflex, ergo no real cone control, but then at his desired peak SPL it's moot. You should get similar/same results in AJ using what I posted. Vent is 3/4" long.
Your scoop bin sim looks good.
GM
that little scoop was 98.5 liters including a huge vent - wow GM - that predtion you did looks similar - how big is its chambers, how many vents and what tunings?
Freddy
ps - am getting confused by AJ's "half-space" vs "floor" and whatever your program means for boundaries under "free air" :^)
Freddy
ps - am getting confused by AJ's "half-space" vs "floor" and whatever your program means for boundaries under "free air" :^)
Hi GM, yep just doing it to do something. I don't have any money at the moment but feel like playing. The KLH is fairly muddy and I am going to build the Tapper so I can install a proper driver in the future if needed. Cheers.
Hi Freddi, I would like to build a pair of Ks but don't have the money for drivers. Cheers.
Hi Freddi, I would like to build a pair of Ks but don't have the money for drivers. Cheers.