Single sheet TH challenge

[Xoc1]

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

[weltersys]

Originally Posted by kg77

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.

[Djim]

Originally Posted by Xoc1

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

[Djim]

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?

[jbell]

hmmm.... my smaart was done with a 40hz@48 - 250hz@24.... Makes me think I should redo that measurement with a 35hzHP....

[Djim]

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...

[kenpeter]

Originally Posted by weltersys

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.

[tb46]

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,

[Djim]

Originally Posted by tb46

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 &#$*&@!

[Djim]

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).