OK, heres the changes i come up with (based on your 56”H i.d.)using the original calculation and expanding every parameter to equal a 38”H tweeter center (ended up as a 33% increase)
new specs: 38” tweeter/12x6 horn centered….10” mtm
All dimensions I.D.
h- 56.00”
w- 23.38”
d- 33.36”
t1- 8.09”
t2- 16.17”
t3- 46.88” +/- 2.33”
t4- 44.49”
LL- 109.52”
believe it or not this size is actually do-able if I make it as a semi-built in for my entertainment center (either side of a 60“ plasma tv) this would also allow me to use my two lab 15 as a third and fourth sub down to 20hz
crazy right? Just have to figure out porting………would aperiodic be on the table?
new specs: 38” tweeter/12x6 horn centered….10” mtm
All dimensions I.D.
h- 56.00”
w- 23.38”
d- 33.36”
t1- 8.09”
t2- 16.17”
t3- 46.88” +/- 2.33”
t4- 44.49”
LL- 109.52”
believe it or not this size is actually do-able if I make it as a semi-built in for my entertainment center (either side of a 60“ plasma tv) this would also allow me to use my two lab 15 as a third and fourth sub down to 20hz
crazy right? Just have to figure out porting………would aperiodic be on the table?
Attachments
Aperiodic is for under damped box alignments and/or where one wants/needs a BR with a sealed alignment roll-off, so in your case with subs your choice of XO point/slope will govern whether or not you need to damp the port.
I'll load it in HR later on today if no one beats me to it, still cleaning up/repairing the latest storm damage.
I'll load it in HR later on today if no one beats me to it, still cleaning up/repairing the latest storm damage.
Hmm, I'm confused..........
T3 = tweeter height s/b 38", right?
c-t-c spacing?
BTW, this is a 25+ft^3 net cab, so a bit bigger overall
T3 = tweeter height s/b 38", right?
c-t-c spacing?
BTW, this is a 25+ft^3 net cab, so a bit bigger overall
yah, i wasn‘t sure how you wanted to get to that 38” tweeter height so i altered the overall dimensions until it got there, thinking not to alter the design ratio………..obviously I thought wrong!
But yes smaller would be better.
Problem is I dont know which dimensions are alter able……..just raise the top (without extending t4) until t4 is in the same relationship (as it was with the original woofer) for the target tweeter ht ?
But yes smaller would be better.
Problem is I dont know which dimensions are alter able……..just raise the top (without extending t4) until t4 is in the same relationship (as it was with the original woofer) for the target tweeter ht ?
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Not doing so well am I ? Its not for lack of trying 😳
GM, ctc spacing for woofers is 16”…….thats as tight as i could get it with the horn i’m using.
GM, ctc spacing for woofers is 16”…….thats as tight as i could get it with the horn i’m using.
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Awesome, you da man! I’d help you fix up from the storm if i were closer, that is definitely inside my wheelhouse 😎
OK, as I presumed from experience it required a huge (2xSd) baffle thickness vent just to tune it in the high 20s and by increasing taper (T1 = 0.00)/reducing (Vb = 18.822 vs 23.667 ft^3) only shifted it up to the high 30s, which increased ~2.5 - 3 dB 30 - 100 Hz with the downside that neither can handle > ~3 - 4 W/Xmax and once the larger cab's spikes are damped, basically fractional watts (all 2pi/half space), so room position is critical unless ~78 dB/stereo average down to 40 Hz is sufficient.
Shrinking it to ~Fs tuning = ~8.292 ft^3, increasing power to ~14 W/106 dB/40 Hz/2pi/stereo average.
Notes:
All Vbs = i.d. net, so need to factor in the driver, slant baffle, bracing losses.
Damping is standard BR, sealed QL = 7, so basically lined or lightly stuffed down to just above the vent.
In short, if one doesn't already know the basics of TL/horn design, best to assume that much vent, damping tweaking will be required with this calculator, which in turn will normally require a larger cab than predicted unless the horn's throat (T1) = ~0.000.
So, which one of these or the MLTLs, if any, do you want to build?
Shrinking it to ~Fs tuning = ~8.292 ft^3, increasing power to ~14 W/106 dB/40 Hz/2pi/stereo average.
Notes:
All Vbs = i.d. net, so need to factor in the driver, slant baffle, bracing losses.
Damping is standard BR, sealed QL = 7, so basically lined or lightly stuffed down to just above the vent.
In short, if one doesn't already know the basics of TL/horn design, best to assume that much vent, damping tweaking will be required with this calculator, which in turn will normally require a larger cab than predicted unless the horn's throat (T1) = ~0.000.
So, which one of these or the MLTLs, if any, do you want to build?
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Thanks so much GM, nothing about that seems worth doing…….reckon i’ll just stick with sealed or ported on top of bass modules, basically a 3-way.
I certainly learned a few things delving into this and I really do appreciate the help, i’m sure it was painful to watch me flounder about! 🤣
Seeing as i have 12 of these i might be able to do a slot loaded thing like Nelson did except just 4 per bottom instead of 6…….i promise to keep it simple!
I certainly learned a few things delving into this and I really do appreciate the help, i’m sure it was painful to watch me flounder about! 🤣
Seeing as i have 12 of these i might be able to do a slot loaded thing like Nelson did except just 4 per bottom instead of 6…….i promise to keep it simple!
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I'm by no means an authority, but I gave it a try modelling as a straight MLTL.
Key dimensions (all internal) are:
Key dimensions (all internal) are:
- 12.5" W x 16.5" D x 50.5" H,
- midpoint of two drivers (& horn) centered 16" from inside-top,
- ports (2x 4" dia x 5" length), centered 4 3/4" from bottom,
- stuffing 1.7 lbs of polyfill in top 2/3 of cabinet.
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That looks quite do able, thanks very much Matt…….some kind of legs would get the tweeter to ear level perfectly. 😎
those dimensions are great and look is quite nice also.
would pass off to to the subs @ around 40-50hz quite well……..subs are those diysg buy out lab 15‘s in 4 cf sealed boxes, powered by crown xls 2002
those dimensions are great and look is quite nice also.
would pass off to to the subs @ around 40-50hz quite well……..subs are those diysg buy out lab 15‘s in 4 cf sealed boxes, powered by crown xls 2002
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Me too! 😉
FYI/FWIW, I intentionally didn't do hardly any damping on the max flat MLTL, MLTQWTs I posted to highlight the differences, so for the record, here's the 'finished' ~213 L net MLTL I posted earlier.
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Yes GM that certainly cleans up nice! whats the box dimensions?
Or is the same as Matts……explaining the wink?
Edit; Matts = 170 L. and yours is 213 L so it must be a little bigger
Or is the same as Matts……explaining the wink?
Edit; Matts = 170 L. and yours is 213 L so it must be a little bigger
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No, just agreeing with his assessment of his design.
The basic dims are the ones I posted here per your original limitations.
OK cool, thanks GM, sorry i was a bit confused when you said 50-150hz bump (thinking 50 was the bottom)…….now that i see the finished fr it would definately be a touch better than Matt’s (no offense Matt!) if i wanted to build that version whats up with the port……just a 8” hole?
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You're welcome!
Actually, the original sim with the boost I posted is what I would build due to knowing that HR (dramatically in some cases ) exaggerates its high Q spikes down to a sufficient in room smoothness with modest damping plus I'd rather have the extra acoustical mid-bass efficiency and EQ down if required for those recordings with powerful drum, bass guitar, etc., solos; but your liking the smoothness of a sim I changed it to a comparable one, forcing a lower ~32 Hz tuning, so leave it at 8" (red) or 5" for max flat.
Actually, the original sim with the boost I posted is what I would build due to knowing that HR (dramatically in some cases ) exaggerates its high Q spikes down to a sufficient in room smoothness with modest damping plus I'd rather have the extra acoustical mid-bass efficiency and EQ down if required for those recordings with powerful drum, bass guitar, etc., solos; but your liking the smoothness of a sim I changed it to a comparable one, forcing a lower ~32 Hz tuning, so leave it at 8" (red) or 5" for max flat.
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Ok, seeing as you have real world (sim to build) experience with HR i will definitely take your word for that, and is exactly what information i’m after.
Questions arise still about the port……
1) Is the shallow (1”) depth what reduces resonance?
2) Is one (8” vs 5”) better than the other regarding resonance, and would a ‘in between’ say 6.5” be a good compromise?
3) If this is how I imagine it, just a hole in the baffle (I usually use 1” ply for baffle so no problem there) can one use grill cloth over it or will that alter it too much?
4) Is port shape critical to the design, or can the round hole be changed to rectangular if it keeps the same area?
One thing i do know is that dimensional accuracy is critical to a mltl build, so if once we boil it down could i get you to list critical dimensions as Matt did?
I applaud your patience! 😎
edit; Is this design basically the same as the old altec,jbl,etc. with just holes in the baffle? I’d always wondered how that was possible.
Questions arise still about the port……
1) Is the shallow (1”) depth what reduces resonance?
2) Is one (8” vs 5”) better than the other regarding resonance, and would a ‘in between’ say 6.5” be a good compromise?
3) If this is how I imagine it, just a hole in the baffle (I usually use 1” ply for baffle so no problem there) can one use grill cloth over it or will that alter it too much?
4) Is port shape critical to the design, or can the round hole be changed to rectangular if it keeps the same area?
One thing i do know is that dimensional accuracy is critical to a mltl build, so if once we boil it down could i get you to list critical dimensions as Matt did?
I applaud your patience! 😎
edit; Is this design basically the same as the old altec,jbl,etc. with just holes in the baffle? I’d always wondered how that was possible.
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