Just thinking out loud here really.
I have a subwoofer that uses a pair of 10-inch Daytons (RSS265HO-44) in a single enclosure, back to back, out of which runs a 3.5m section of 250mm diameter storm water pipe, snaking its way round the back of the TV in an inverted U shape.
Im wondering whether it is possible to model what effect two sections of 150mm pipe would have, given their cross sectional area combined is roughly similar (35cm2 vs 45cm2).
And if possible then how long the lines have to be?
I have a subwoofer that uses a pair of 10-inch Daytons (RSS265HO-44) in a single enclosure, back to back, out of which runs a 3.5m section of 250mm diameter storm water pipe, snaking its way round the back of the TV in an inverted U shape.
Im wondering whether it is possible to model what effect two sections of 150mm pipe would have, given their cross sectional area combined is roughly similar (35cm2 vs 45cm2).
And if possible then how long the lines have to be?
See attached.
I also had a thought of using three of the smaller 150mm pipes instead, as the surface area of the triple line is 53cm2 vs 45cm2 of the single 250mm pipe.
And I guess the length of the line(s) would be the same (3.5m).
The other 10-inch driver is hidden, on the opposite side of the sub box, so back to back.
I also had a thought of using three of the smaller 150mm pipes instead, as the surface area of the triple line is 53cm2 vs 45cm2 of the single 250mm pipe.
And I guess the length of the line(s) would be the same (3.5m).
The other 10-inch driver is hidden, on the opposite side of the sub box, so back to back.
Attachments
Actually we are both on the same page.
My calcs give 25cm area of the line at 490 (I misquoted it at 450) and three times the 176 figure for the 15cm tube is 530 odd.
What Im saying is that three tubes of 15cm diameter is roughly equivalent to 1 tube of 25cm in terms of line area.
Just wondering whether any of the sim programmes can assess the effect of three lines instead of one? Or is this just a nonsense because three small lines with the same surface area as one larger line will be identical in terms of how they sim and sound if they are the same length?
My calcs give 25cm area of the line at 490 (I misquoted it at 450) and three times the 176 figure for the 15cm tube is 530 odd.
What Im saying is that three tubes of 15cm diameter is roughly equivalent to 1 tube of 25cm in terms of line area.
Just wondering whether any of the sim programmes can assess the effect of three lines instead of one? Or is this just a nonsense because three small lines with the same surface area as one larger line will be identical in terms of how they sim and sound if they are the same length?
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???
15 cm diameter/2 = 7.5 cm radius
7.5^2*pi = ~176.7146 cm^2 same as mine using its diameter to save a calculation step.
pi = ~3.1416
GM
15 cm diameter/2 = 7.5 cm radius
7.5^2*pi = ~176.7146 cm^2 same as mine using its diameter to save a calculation step.
pi = ~3.1416
GM
What you said I agree with:
15 cm dia = 15^2*pi/4 = ~176.7146 cm^2, 25 cm = ~490.8739 cm^2 = ~2.78x larger.
The 15cm pipe has Xsectional area of 176cm2
The 25cm pipe has Xsectional area of 490cm2.
So three 15cm pipes have roughly (530cm2) the same X-sectional area as one 25cm pipe at 490cm2, right?
So in a sim if I used a single 26mm pipe with a cross sectional area of 530cm2 this would give precisely the same results if I ended up actually building something with three 15cm pipes instead, correct?
15 cm dia = 15^2*pi/4 = ~176.7146 cm^2, 25 cm = ~490.8739 cm^2 = ~2.78x larger.
The 15cm pipe has Xsectional area of 176cm2
The 25cm pipe has Xsectional area of 490cm2.
So three 15cm pipes have roughly (530cm2) the same X-sectional area as one 25cm pipe at 490cm2, right?
So in a sim if I used a single 26mm pipe with a cross sectional area of 530cm2 this would give precisely the same results if I ended up actually building something with three 15cm pipes instead, correct?
'Roughly', yes, but ~530 cm IS larger, hence the 26 cm pipe will need to be longer for a given tuning due to increased friction of more internal pipe surface area.
Using [3] 15 cm pipes with all its extra internal area just compounds the problem.
AkAbak is the only program I know of that can accurately sim multiple ports, but too tedious for me, so no clue how much higher tuned these two variants will be at the current 3.5 m axial length.
GM
Using [3] 15 cm pipes with all its extra internal area just compounds the problem.
AkAbak is the only program I know of that can accurately sim multiple ports, but too tedious for me, so no clue how much higher tuned these two variants will be at the current 3.5 m axial length.
GM
if I understood correctly that the drivers box would movie to dead center (?) of the twin pipes, then there might be some cancellation effect which to deal. Having two separate enclosure - pipe assemblies should work ok,
No, the layout would be unchanged; only the top plate would be different. It is purely for aesthetics so I can hide more of the 'plumbing' behind the TV.
What concerns me really is whether the change in pipe cross-sectional area from 490 to 530cm2 would affect the outcome adversely.
And yes, it does sound great, digs low and clean, as it is now with the 25cm diameter pipe.
Thanks for taking the time to sim it Freddi.
What concerns me really is whether the change in pipe cross-sectional area from 490 to 530cm2 would affect the outcome adversely.
And yes, it does sound great, digs low and clean, as it is now with the 25cm diameter pipe.
Thanks for taking the time to sim it Freddi.
if the overall drag doesn't change much then (btw - those left right elbow speaker cabinets are beautiful !)
light = 530 - - bold = 490
light = 530 - - bold = 490
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