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Old 18th March 2011, 09:49 PM   #711
Xoc1 is offline Xoc1  United Kingdom
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Default SS15 Analysis

For what its worth I have done another unfolded drawing analysis of the SS15
as Djim requested.
The dimensions are as accurate as I can acheive given the available drawings.
The central 8" divider is reduced to 7 3/4" as Jbell commented.
No attempt at suggesting how to emulate this in hornresp. or any adjustment for the driver volume. This is as close as I can get to Jbells as built box.

The internal volume of the box is 223 Litres
The equivalent unfolded horn is 225 Litres. This represents an error of less than 1%

The PDF should be printed as as 100% on A4 for 1:10 scale.

Can the SS15 be improved?- Probably, but you might need to relax the single sheet rule to acheive it
Attached Files
File Type: pdf J Bell SS15 Unfolded .PDF (67.8 KB, 144 views)
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Old 18th March 2011, 09:55 PM   #712
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Quote:
Originally Posted by kg77 View Post
is it possible to mix box types. example, could u make a bandpass design with a TH/tline in one chamber and a ported design in the other.?

how would u control the phase/position of the wave to create a fatter sounding box?.
I suppose "u" could make a bandpass design with a TH/tline in one chamber and a ported design in the other. I have no idea what it would sound like, or why "u" would want to.

Phase response of any box is dependent on a large number of variables. The last thing I want is a "fatter sounding" box, I want a box with as flat frequency and phase response possible over the widest range.

The phase response of a properly designed horn or TH will be smoother over a wider range than a BR (AKA phase inversion) box.

I suggest you start another thread with your questions about other box types and hybrids, they really have nothing to do with the SS15.
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Old 18th March 2011, 10:19 PM   #713
Djim is offline Djim  Netherlands
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Quote:
Originally Posted by Xoc1 View Post
For what its worth I have done another unfolded drawing analysis of the SS15 as Djim requested.
The dimensions are as accurate as I can acheive given the available drawings. The central 8" divider is reduced to 7 3/4" as Jbell commented.
No attempt at suggesting how to emulate this in hornresp. or any adjustment for the driver volume. This is as close as I can get to Jbells as built box.
The internal volume of the box is 223 Litres
The equivalent unfolded horn is 225 Litres. This represents an error of less than 1%

The PDF should be printed as as 100% on A4 for 1:10 scale.

Can the SS15 be improved?- Probably, but you might need to relax the single sheet rule to acheive it
Thanks Martin and of course this will help! And your PDF integrates perfectly within the 1:10 ratio in Photoshop
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Old 19th March 2011, 12:39 AM   #714
Djim is offline Djim  Netherlands
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Here is a graphic representation of 2 Butterworth 48dB per Octave - lowcut filters. One is set to 40Hz (for standard SS15) and the other at 33Hz (Extended SS15).

As you can see the difference between the filters at:

35Hz = 7dB
40Hz = 4,5dB
45Hz = 1,9dB
50Hz = 0,9dB

So even IF the extended version is not more efficient at 40Hz there still will be a difference of +4,5dB in favour of the Extended at 40Hz and +7dB in favour of the Extended at 35Hz.

I believe my prediction of +5dB at least and probably +7dB at 40Hz is not that unrealistic, and who was blaming who about exaggerating?
Attached Images
File Type: jpg Butterworth_48dB_33-40Hz.JPG (63.8 KB, 376 views)

Last edited by Djim; 19th March 2011 at 12:45 AM.
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Old 19th March 2011, 03:06 AM   #715
jbell is offline jbell  United States
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hmmm.... my smaart was done with a 40hz@48 - 250hz@24.... Makes me think I should redo that measurement with a 35hzHP....
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Old 19th March 2011, 03:16 AM   #716
Djim is offline Djim  Netherlands
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I was hoping you were reading this :-) but don't use any type of filtering with 1V/1M measurements.

Now you understand my motivation for Pe -10dB measurements instead of a steady number like 28,3V/10m. At Pe -10dB all PA drivers are safe and you don't need to worry about excursion to much. Also it shows the performance of each driver at the exact same point so high power drivers have not an advantage...
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Old 19th March 2011, 03:19 AM   #717
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Quote:
Originally Posted by weltersys View Post
If there is anyone that has used the keystone shaped exit on a TH before me, I am unaware of it.
Karlson K15... Definately tapped and "keystoned?", but horn???
Karlson himself often claimed it was mathematically equivalent.
And Klipsh would flip his BS tie every time that was said...

Using multiple stagger tuned resonant chambers rather than a
much longer and voluminous expanding path, its never been
modeled correctly that I know of. I could not explain exactly
why it works, but definitely does not suck in the 1 sheet dept.

Yeah, that undersized thing is only a DeltaPro12 in the picture.
There's a SigmaPro18-A2 in there now, just barely fit... 18 goes
much much lower, but the 12 really "hit" insanely hard.

No special reason couldn't have been mounted magnet forward
if only gonna serve as a sub and not full range. OK, that might
not be as simple as I just claimed, the baffles a little too close
to the front exit if built to the original plan.
Attached Images
File Type: jpg K15Front.jpg (67.4 KB, 377 views)
File Type: jpg 0919225410.jpg (283.7 KB, 364 views)
File Type: jpg K15Guts.jpg (68.7 KB, 340 views)

Last edited by kenpeter; 19th March 2011 at 03:49 AM.
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Old 19th March 2011, 03:49 AM   #718
tb46 is offline tb46  United States
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Default Post #691 - Continued

Hi Y'all,

Another page in the story of the SS15, sadly it's still not getting better. I believe using Xmax in the passband as a comparison is valid. Anyway, again Hornresp inputs, and combined SPL. Additionally I'll post a .pdf with the original, and the redrawn versions of Djim's Post #691 (and don't even ask, I'm not going to do a layout of the original this was already way to much time spend on this idea :-), should anyone have a need for the original Acad 14 .dwg just PM me).

Y'all have been busy, and Xoc1 has outdone himself in the drawing department.

Regards,
Attached Images
File Type: jpg SS15_Xmax.jpg (40.3 KB, 340 views)
File Type: jpg Djim_Post_691_redraw_Xmax.jpg (38.1 KB, 56 views)
File Type: jpg SS15_Djim_Post_691_redraw_Xmax_SPL.jpg (32.1 KB, 107 views)
Attached Files
File Type: pdf Djim_SS15_Mod_Post_691.pdf (82.5 KB, 67 views)
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Last edited by tb46; 19th March 2011 at 03:51 AM.
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Old 19th March 2011, 04:40 AM   #719
Djim is offline Djim  Netherlands
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Quote:
Originally Posted by tb46 View Post
Hi Y'all,
Another page in the story of the SS15, sadly it's still not getting better. I believe using Xmax in the passband as a comparison is valid. Anyway, again Hornresp inputs, and combined SPL. Additionally I'll post a .pdf with the original, and the redrawn versions of Djim's Post #691 (and don't even ask, I'm not going to do a layout of the original this was already way to much time spend on this idea :-), should anyone have a need for the original Acad 14 .dwg just PM me). Y'all have been busy, and Xoc1 has outdone himself in the drawing department.
Regards,
Oliver I have to admit you have done another tremendous job, and many thanks for that.... The drop in SPL is no problem but dear oh dear...that path length (this frase is followed by a big sigh, a verrrry deep big sigh). I desperately needed that 280cm (110inches) in path length, this is 'just' 45Hz instead of the original 47Hz! By bringing S1 up to the top I can gain what... 10cm (4inches)... that brings me to 44Hz, still not enough....Aaahhhrrrggg &#$*&@!
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Old 19th March 2011, 04:58 AM   #720
Djim is offline Djim  Netherlands
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Oliver, could you please check the path length cause when I put the new path length on top of the original SS15 path, I see considerably more length then just the extra 10cm. Or what am I doing wrong here? (I have perfectly scaled each drawing so the outlines of the cab are exactly the same).

Last edited by Djim; 19th March 2011 at 05:01 AM.
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