I've attached the original 6 Fold sketche; the 2nd sketch with the addition of the S1 angle piece; the cab dims of each; and the baffle cut-out I'm currently using. Big thanks goes out to Martin for these beautiful sketches.
Attachments
Just remembered I'm only using a 1/2" spacer - I may have been hearing the edge of the cone or surround hit the baffle..??
I'm so excited, I will get to play with 4 of them in a few months
Fantastic! What drivers will you be using?
whe stil have to decide on a th fold to replace our eaw SB850's (thats 32 18"cones)
whe have to consider truc space,transportabilety and weight.
or whe sell them and buy 12".
Sounds massive. How do you like that setup? I'm sure you have considered the TH-18. Is that a viable option for you?
btw i only count 5 folds
You can blame Martin for that
jk. Maybe it should be called the '6 Section TH' ;P
Sorry martin,i just learned to count.
Yes it has been a while,but the exchange of ideers in this topic is great.
@ justin.
Actualy the eaw's are not mine but from a friend .
Whe just don't like how they sound(subs)
All options incl th 118 are open.
atm 4 fold 5 section (dag johanson) as model ,comes closest to what we need.
Yes it has been a while,but the exchange of ideers in this topic is great.
@ justin.
Actualy the eaw's are not mine but from a friend .
Whe just don't like how they sound(subs)
All options incl th 118 are open.
atm 4 fold 5 section (dag johanson) as model ,comes closest to what we need.
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I'd love to see some real world measurements of these. Maybe you'll be the 1st
Hey, I'll give him some competition on that!
I just need a mic to my Ipad.
Dag
From the recently posted results in the Single Sheet Challenge thread showing low and high level testing, the SS15 loaded with 3015LF constructed of 1/2" plywood also has no shortage of power compression, coming up way shy of a linear voltage in, SPL out result.
Alas, there are compromises using ultra light cone material and thin cabinet walls
...
Originally posted by weltersys:
From the recently posted results in the Single Sheet Challenge thread showing low and high level testing, the SS15 loaded with 3015LF constructed of 1/2" plywood also has no shortage of power compression, coming up way shy of a linear voltage in, SPL out result.
A linear voltage in/ SPL out result, would be, for instance, 2.83 v applied to a cabinet resulting in 100 dB SPL at one meter, 28.3 v resulting in 120 dB SPL.
In post # 1492, “Single sheet TH challenge”, Crescendo measured his 3015LF loaded, 1/2” Aruco plywood SS15 cabinets at:
70Hz: 103.2 dBC, 2.83 v at one meter
70Hz, 124.7dBC, QSC PLX3402 amplifier “just at clip” ( about 75 volts, 700 watts at 8 ohm)
Had there been a linear voltage in/SPL out relationship, 700 watts/75 volts would have resulted in about a 28.5 dB increase in SPL, 131.7 dBC.
The cabinet fell far short of 131.7 dBC.
131.7-124.7 = 7 dB of power compression.
What % of power compression is from voice coil heat, exceeding Xmax, cone flex, or wood deflection is conjecture.
On a (presumably) short test, the voice coil should not heat much, exceeding Xmax, cone flex and wood deflection are the more likely dominant compression features in Crescendo’s test.
IIRC, Tom Danley mentioned a 3 dB under prediction measured loss in a large, multiple 18” cabinet which required stepping up from 3/4” to one inch Baltic Birch with more extensive bracing to get the SPL up to the predicted level.
Jim (jbell, the SS15 designer) mentioned some 3/8" deflection of the SS15 front panel at high power some time back, deflection could amount to almost half of the measured upper frequency power compression losses.
I avoid light cones and thin wood in construction of bass cabinets that I wish to get loud and clean.
I have measured the Keystone sub loaded with the BC 18SW115-4 at close to 130 dB, though less sensitive than the SS15 (but with much lower frequency extension) it has virtually no power compression with sine waves well above it’s rated AES power level, resulting in far more usable, clean output.
To repeat, there are compromises using ultra light cone material and thin, inadequately braced cabinet walls.
Art Welter
From the recently posted results in the Single Sheet Challenge thread showing low and high level testing, the SS15 loaded with 3015LF constructed of 1/2" plywood also has no shortage of power compression, coming up way shy of a linear voltage in, SPL out result.
Dan,
A linear voltage in/ SPL out result, would be, for instance, 2.83 v applied to a cabinet resulting in 100 dB SPL at one meter, 28.3 v resulting in 120 dB SPL.
In post # 1492, “Single sheet TH challenge”, Crescendo measured his 3015LF loaded, 1/2” Aruco plywood SS15 cabinets at:
70Hz: 103.2 dBC, 2.83 v at one meter
70Hz, 124.7dBC, QSC PLX3402 amplifier “just at clip” ( about 75 volts, 700 watts at 8 ohm)
Had there been a linear voltage in/SPL out relationship, 700 watts/75 volts would have resulted in about a 28.5 dB increase in SPL, 131.7 dBC.
The cabinet fell far short of 131.7 dBC.
131.7-124.7 = 7 dB of power compression.
What % of power compression is from voice coil heat, exceeding Xmax, cone flex, or wood deflection is conjecture.
On a (presumably) short test, the voice coil should not heat much, exceeding Xmax, cone flex and wood deflection are the more likely dominant compression features in Crescendo’s test.
IIRC, Tom Danley mentioned a 3 dB under prediction measured loss in a large, multiple 18” cabinet which required stepping up from 3/4” to one inch Baltic Birch with more extensive bracing to get the SPL up to the predicted level.
Jim (jbell, the SS15 designer) mentioned some 3/8" deflection of the SS15 front panel at high power some time back, deflection could amount to almost half of the measured upper frequency power compression losses.
I avoid light cones and thin wood in construction of bass cabinets that I wish to get loud and clean.
I have measured the Keystone sub loaded with the BC 18SW115-4 at close to 130 dB, though less sensitive than the SS15 (but with much lower frequency extension) it has virtually no power compression with sine waves well above it’s rated AES power level, resulting in far more usable, clean output.
To repeat, there are compromises using ultra light cone material and thin, inadequately braced cabinet walls.
Art Welter
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yes... yes there are.... and when I'm hanging them 30' in the air... all of those compromises are worth it.
We smelled, followed by seeing, smoke come from the driver during sine wave test at just under clipping for probably no more than 5 or 6 sec - had to shorten the durations even more. That's when the SPL meter's peak hold function came in handy.
If the voice coil was emitting visible smoke, some thermal compression probably was taking place
.Did you happen to look at the excursion during any of your high power tests?
Art
SS15 cries for something like a 18TBW100 and life is good again...imo
all subs are comprises.
lets not forget the origin of the ss15
the goal was to make a light weight cheap efficient sub out of 1 sheet.
that goal is reached .
if you want more spl,lower ect.you have to make it bigger ,heavier,more expencive ...
Now as it is they have been taken in by the specmanship, the gap is taller than the exposed coil fellas:
