Physics Research - SupraBaffles

stpeter · 23rd September 2008, 12:48 AM

I've been haunting around this forum for a while and have been loving what I've run into so far, and have gone far enough to make myself a pair of Half-Chang's

To make a long story short I have to do some sort of research for my undergrad physics.

So now I have come to the experts for some advise. I was interested in doing my research on the effect of Suprabaffle shape on the response and investigating the diffraction and all that fun stuff. My basic plan of attack was to build one (pair of) cabinet (s) with a removable and interchangeable suprabaffle system. This way I can keep most everything the same except the suprabaffle and observe the results.

So my question is, what cabinet do you guys feel would facilitate itself best to this purpose? I'm entirely open to suggestions, but i was hoping to find one that wasn't super complicated to build. My hopes were to work with one of the Fostex 4 inch or 4.5 inch drivers.

And help or advise you guys can offer me is greatly appreciated.

Thanks again

loninappleton · 23rd September 2008, 04:43 AM

http://www.zillaspeak.com/bib-howtobuild.asp

Scroll down to see a BIB with supra baffle in the Planet 10 drawing.

Also Bob Brines has shown some designs of the suprabaffle on his
MLTL designs for larger 6.5 in Fostex.

The BIB mentioned above can be dimensioned for any speaker
from small to big and the calculator at the Zilla site has some
samples for the most popular Fostex and other full range speakers.

My take on it is that the suprabaffle, round or oval by increasing the
depth of the cutout changes the BLH action on the BIB which I didin't care for. No proof, just my preference.

But my suprabaffle test was done with a calculated oval, just something that was close.

Your test results will be most appreciated.

DaveCan · 23rd September 2008, 05:02 AM

For an uncomplicated build, and for a 4 to 4.4'' Fostex driver as inquired ,I'd also vote for a BIB, but inverted so it fires to the floor etc.. After that the A126 would get my vote, and then some of the BVR`s, that`s just me.. Dave

planet10 · 23rd September 2008, 05:52 AM

Hi,

This would be some VERY valuable research. For maximum results you want a skinny cabinet without any main cab above the driver. You'd also like to be able to pull the box out from the wall.

Rules out BIB, Saburo, or any of the double-mouth Spawn.

The Frugel-Horn would be a good vehicle, but doesn't fit the easy to build. Your best bet would be Suzy (FE107) or a half-Olivia or the Floorstander Fonken that Olivia was derived from.

The extra extension of the FE127 would be very useful for this research, and of the 2 cabs for it suggested, a half-Olivia would be best.

Now half-Oliva doesn't exist, but once Scott finds out about this i expect we could easily get that together just for your research project.

dave

Scottmoose · 23rd September 2008, 06:55 AM

Not a problem. I'll get a box sorted out for you ASAP.

stpeter · 23rd September 2008, 07:44 PM

Thanks for the help everyone

I was too thinking BIB at first, but the point about the cab not extending above the driver makes sense.

I was also considering building a Frugal-horn... and in theory I could make it happen, but I figured a simple cab would be better. If you guys would suggest above all else a frugal-horn i'll go ahead and do that.

Anything that you guys can throw together would be greatly appreciated and I will forever be in your debt.

Svein_B · 23rd September 2008, 08:08 PM

For this type of experiment I would suggest a simple, slim cabinet as a closed box, or possibly a BR / MLTL.

Any kind of horn construction willl usually have many dips and peaks that will make repeatability of measurements under different conditions difficult to interpret.

SveinB

Scottmoose · 23rd September 2008, 08:46 PM

Nice simple single Olivia box now done. Should be ideal for this -moderately tall, slim, driver near the top, nice smooth response & a doddle to build. Dave has the dimensions. Similar mods will be applied to the double box too, which should improve clarity of the bottom end a bit.

DaveCan · 23rd September 2008, 09:11 PM

Why does it matter if any main cab is above the driver such as in the BIB? The driver still has to dump sound energy down the cab under the driver in most cabs anyway, and the rest goes over the top etc, so why not have the frontal energy somewhat equal? I can't really see how this matters much,?? and this research could still be very useful for taller cabs that have a significant amount of box above the driver etc.. Dave

Scottmoose · 23rd September 2008, 09:53 PM

I know what you mean. Generally though, there are more boxes with the driver near the top than otherwise. Law of averages really.

23rd September 2008, 12:48 AM	#1
stpeter diyAudio Member Join Date: Jan 2008	Physics Research - SupraBaffles I've been haunting around this forum for a while and have been loving what I've run into so far, and have gone far enough to make myself a pair of Half-Chang's To make a long story short I have to do some sort of research for my undergrad physics. So now I have come to the experts for some advise. I was interested in doing my research on the effect of Suprabaffle shape on the response and investigating the diffraction and all that fun stuff. My basic plan of attack was to build one (pair of) cabinet (s) with a removable and interchangeable suprabaffle system. This way I can keep most everything the same except the suprabaffle and observe the results. So my question is, what cabinet do you guys feel would facilitate itself best to this purpose? I'm entirely open to suggestions, but i was hoping to find one that wasn't super complicated to build. My hopes were to work with one of the Fostex 4 inch or 4.5 inch drivers. And help or advise you guys can offer me is greatly appreciated. Thanks again

23rd September 2008, 05:52 AM	#4
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	Hi, This would be some VERY valuable research. For maximum results you want a skinny cabinet without any main cab above the driver. You'd also like to be able to pull the box out from the wall. Rules out BIB, Saburo, or any of the double-mouth Spawn. The Frugel-Horn would be a good vehicle, but doesn't fit the easy to build. Your best bet would be Suzy (FE107) or a half-Olivia or the Floorstander Fonken that Olivia was derived from. The extra extension of the FE127 would be very useful for this research, and of the 2 cabs for it suggested, a half-Olivia would be best. Now half-Oliva doesn't exist, but once Scott finds out about this i expect we could easily get that together just for your research project. dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

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23rd September 2008, 04:43 AM	#2
loninappleton diyAudio Member Join Date: Feb 2004 Location: Appleton, WI	http://www.zillaspeak.com/bib-howtobuild.asp Scroll down to see a BIB with supra baffle in the Planet 10 drawing. Also Bob Brines has shown some designs of the suprabaffle on his MLTL designs for larger 6.5 in Fostex. The BIB mentioned above can be dimensioned for any speaker from small to big and the calculator at the Zilla site has some samples for the most popular Fostex and other full range speakers. My take on it is that the suprabaffle, round or oval by increasing the depth of the cutout changes the BLH action on the BIB which I didin't care for. No proof, just my preference. But my suprabaffle test was done with a calculated oval, just something that was close. Your test results will be most appreciated.

23rd September 2008, 05:02 AM	#3
DaveCan diyAudio Member Join Date: Nov 2005 Location: Moncton NB	For an uncomplicated build, and for a 4 to 4.4'' Fostex driver as inquired ,I'd also vote for a BIB, but inverted so it fires to the floor etc.. After that the A126 would get my vote, and then some of the BVR`s, that`s just me.. Dave

23rd September 2008, 06:55 AM	#5
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Not a problem. I'll get a box sorted out for you ASAP.

23rd September 2008, 07:44 PM	#6
stpeter diyAudio Member Join Date: Jan 2008	Thanks for the help everyone I was too thinking BIB at first, but the point about the cab not extending above the driver makes sense. I was also considering building a Frugal-horn... and in theory I could make it happen, but I figured a simple cab would be better. If you guys would suggest above all else a frugal-horn i'll go ahead and do that. Anything that you guys can throw together would be greatly appreciated and I will forever be in your debt.

23rd September 2008, 08:08 PM	#7
Svein_B diyAudio Member Join Date: Oct 2005	For this type of experiment I would suggest a simple, slim cabinet as a closed box, or possibly a BR / MLTL. Any kind of horn construction willl usually have many dips and peaks that will make repeatability of measurements under different conditions difficult to interpret. SveinB

23rd September 2008, 08:46 PM	#8
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Nice simple single Olivia box now done. Should be ideal for this -moderately tall, slim, driver near the top, nice smooth response & a doddle to build. Dave has the dimensions. Similar mods will be applied to the double box too, which should improve clarity of the bottom end a bit.

23rd September 2008, 09:11 PM	#9
DaveCan diyAudio Member Join Date: Nov 2005 Location: Moncton NB	Why does it matter if any main cab is above the driver such as in the BIB? The driver still has to dump sound energy down the cab under the driver in most cabs anyway, and the rest goes over the top etc, so why not have the frontal energy somewhat equal? I can't really see how this matters much,?? and this research could still be very useful for taller cabs that have a significant amount of box above the driver etc.. Dave

23rd September 2008, 09:53 PM	#10
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	I know what you mean. Generally though, there are more boxes with the driver near the top than otherwise. Law of averages really.

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