Freddi,
The Kappa 12a (mentioned in those most recent drawings) has a frame diameter of 12.26" , and some 12s might even be slightly larger, so you will want to give yourself at least 12.5" of internal width (13.5" external) if you want the cabinet to be compatible
The gaps up front look perfect now
NOTE: If you want to compensate for the internal volume taken up by panels, driver, and bracing it can be done with a minor increase in the cabinet's outer dimensions ..
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to be compatible - maybe the adapter board for the 10 would go behind the baffle, then the frame of the 1o would not be jutting out so much, necessatating a removable back panel (weakening the structure) The back panel could be made thicker.
do you think it holds promise with 12" speakers ? I figure the baffle would need to be about 13" square.
With hornresp's wizard, added width effects can be examined.
here's it with just the width increased to 13" vs 12" internal width.
If the baffle is made taller - would you alter its angle , etc? Irs pretty close at 3.6" or so (If
I drew it close)
do you think it holds promise with 12" speakers ? I figure the baffle would need to be about 13" square.
With hornresp's wizard, added width effects can be examined.
here's it with just the width increased to 13" vs 12" internal width.
If the baffle is made taller - would you alter its angle , etc? Irs pretty close at 3.6" or so (If
I drew it close)
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Freddi ,
Alright we could stick with the 17.5" outer height at the new width (at least 12.5" internal width or 13.5" external minimum width in order to host a variety of 12s )... The small amount of extra internal volume that this will give us should not be a problem
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MMJ - here's a rough look at 16.5" internal height - I can't figure out how to get the front chamber and port right
making it wider and keeping port and stub areas the same as before reduces the gap to 1.75" (I think - have to look at the input screen - -1.7 height) and makes the stub tunnel a bit deeper
What to do with the front chamber and port below if its going to use a 12" speaker, work well and sound OK?
making it wider and keeping port and stub areas the same as before reduces the gap to 1.75" (I think - have to look at the input screen - -1.7 height) and makes the stub tunnel a bit deeper
What to do with the front chamber and port below if its going to use a 12" speaker, work well and sound OK?
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Well ok, it looks like your interchamber duct now has some length to it , so you can increase "Lpt" in model to see what effect it has ...... I just increased the Lpt on my end to 4.8cm and it doesn't alter things by much, just a minor change in response and the cabinet's fundamental tuning shifted downward by a very small amount, no big deal
... Will you be able to reach the screws or bolts that hold the driver in at the top?
That would be my biggest concern here .. .Another solution to this would be to make the cabinet one inch taller which would give you more flexibility on the angle of the baffle
- don't thnk the top screws could be accessed from the front with that duct angle. 17"-17.5" outside height seems to be enough for a 10" speaker and not give as much duct effect.
also am mulling over a 15" Karlflex ss a future project to compare to Acoustic's 115BK which is excellent. As you pointed out, JBL's M151 has a very short overhang as was designed as a guitar speaker with a 3dB compression lfigure @150 watts. K15 loaded it down to 37Hz real well 20vrms while it moved much more in a reflex the size of K15's back chamber with similar tuning (upper 40s)
2035H is kinda like a 6 ohm or 5.5 ohm driver
even with a stub, perhaps the Karlflex are antiquated compared to some hybrid of the same size ? (maybe not in some cases ?)
M151 is crammed into a 25 liter rear chamber below.
I've played bass guitar gigs before with worse cabinets - lilke my 30W Traynor EL34 combo amp
with 2lb output transformer and 15" CTS speaker crammed into less than 2CF.
this might have been another amp
YouTube
also am mulling over a 15" Karlflex ss a future project to compare to Acoustic's 115BK which is excellent. As you pointed out, JBL's M151 has a very short overhang as was designed as a guitar speaker with a 3dB compression lfigure @150 watts. K15 loaded it down to 37Hz real well 20vrms while it moved much more in a reflex the size of K15's back chamber with similar tuning (upper 40s)
2035H is kinda like a 6 ohm or 5.5 ohm driver
even with a stub, perhaps the Karlflex are antiquated compared to some hybrid of the same size ? (maybe not in some cases ?)
M151 is crammed into a 25 liter rear chamber below.
I've played bass guitar gigs before with worse cabinets - lilke my 30W Traynor EL34 combo amp
with 2lb output transformer and 15" CTS speaker crammed into less than 2CF.
this might have been another amp
YouTube
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Hey MMJ - -another try to accomodate a 12" speaker. This one, using 1/2" plywood, a ~13.5x13.5 baffleand outer dims of: 19"H x 14.5" W x 11.5"D to geve an external bulk of ~52 liters; 9.6 liter front chamber, ~25 liters for back chamber after 12" driver and brace displacement. Oops - I probably left out that 1.75"x1.75"x13.5" section in front ot the stub so that puts the front chamber volume up a bit over 10 liters.
The angle could be left alone and scoot the baffle assembly and port a bit towards the rear of the enclousure
giving more front chamber (if good) and slikghtlyh better clearance - even 3/8" might help things - if needed
and share ~1.5 liters off the rear chamber cutting it down to about 23.5 liters (this is a crazy tight little cabinet - lol)
(Does the cone's volume add to the front chamber?)
Should the baffle tilt back "a bit" more to get closer to a 2:1 chamber ratio? - that makes the port a bit longer. Not ro worry ??
Whaddya think ? the drawing is primitive - but pretty much to scale
Port area at its exit ~152. sq.cm.
The angle could be left alone and scoot the baffle assembly and port a bit towards the rear of the enclousure
giving more front chamber (if good) and slikghtlyh better clearance - even 3/8" might help things - if needed
and share ~1.5 liters off the rear chamber cutting it down to about 23.5 liters (this is a crazy tight little cabinet - lol)
(Does the cone's volume add to the front chamber?)
Should the baffle tilt back "a bit" more to get closer to a 2:1 chamber ratio? - that makes the port a bit longer. Not ro worry ??
Whaddya think ? the drawing is primitive - but pretty much to scale
Port area at its exit ~152. sq.cm.
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and here's a triple-fudged sim (I've no idea how the volumes shown in the fudge correlate to the volume in my drawing above - MMJ - this thing was initially scaled from your Freddi-mod Kappa 12 Karlflex)
would be a happy camper if something close to the sim
I think we can just wish and will it into existance
would be a happy camper if something close to the sim
I think we can just wish and will it into existance
Freddi,
These all look great to me
I think You may be ready to have your "Kutter" build this box! That tapered interchamber duct will tune the cabinet lower by just a few hertz but nothing significant, only very minor, no problem , totally cool
.. ..
the question of the aperture arises - what does one really want for this cabinet to be K-ish and to perform reasonably well? I assume in this case the aperture's top should start right below the port's lower boundary (?)
K15's top aperture gap was probably chosen as a half wavelength of 20KHz. With this truncated structure, not sure what gap and what "flare" might be favorable - any thoughts MMJ ?
K15's top aperture gap was probably chosen as a half wavelength of 20KHz. With this truncated structure, not sure what gap and what "flare" might be favorable - any thoughts MMJ ?
depending upon radius and segment, a radial arc aperture might be pretty snall and narrow overall. Matthew, what's your thoughts on a better aperture than the example below ? Being in proximity to the port, I imagine the aperture plate effectively lengthens the port and lowers system tuning - but by how "much" ? Much of the effective speaker width is like 2"-5" below
btw - - life is dearly short - this marks the 5th year of this thread and subjectively seems like "yesterday"
btw - - life is dearly short - this marks the 5th year of this thread and subjectively seems like "yesterday"
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