Look at the Madisound BK12M enclosure for the FE126EN. I used that as the basic design and shrunk the driver chamber volume and divided the channels down the middle ( sagital plane) then modified sections of the channels to make one shorter than the other. By dividing the channels i mean that i am keeping the overall csa of the horn passage the same but cutting it into two halves. A picture would be worth a thousand words and I will post something tomorrow to make it clear.
So it is a box. But.... there is nothing that says that I can't take that box design and roll it up like a Danish or a Cornu with two horns in this case.
So it is a box. But.... there is nothing that says that I can't take that box design and roll it up like a Danish or a Cornu with two horns in this case.
Cool. Im thinking of designing a double horn BLH with different length horns for my TB W5-1611. But thats for a different thread. Lookin for ward to reading ur posts about the development
Regards /Bo
Flat to 4 Hz would be real nice
Im working on a sketch/drawing with dimensions. Should be in a new thread here very soonRegards /Bo
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Double Uneven Length Rear Firing BLH with dual Vifa's
It is quite surprising that the Vifa TC9FD, with its rather high Qts of 0.89 can be made to work well in a BLH with dual uneven length rear firing horns. The simulation in AkAbak shows that this design can achieve modest bass down to about 60 Hz in the 92 dB range using dual drivers wired in parallel. The uneven length horns allow the big hole that was previously at 200 Hz to get filled in. The response, once smoothed with a bit of stuffing in the driver chamber will give a very 'full' bass feeling as there is good coverage all the way up to 300 Hz. So a set of 3.5 inch 2x$12=$24 drivers in this double horn cabinet can actually produce a response that almost rivals a $48 FE126EN with smoother coverage over the 200 Hz range, no shoutiness peak at 7 kHz that the Fostex is known for, and giving up a little bit of bass extension which is to be expected when using a dual horn cabinet without really changing the overall length of the horn substantially.
It is quite surprising that the Vifa TC9FD, with its rather high Qts of 0.89 can be made to work well in a BLH with dual uneven length rear firing horns. The simulation in AkAbak shows that this design can achieve modest bass down to about 60 Hz in the 92 dB range using dual drivers wired in parallel. The uneven length horns allow the big hole that was previously at 200 Hz to get filled in. The response, once smoothed with a bit of stuffing in the driver chamber will give a very 'full' bass feeling as there is good coverage all the way up to 300 Hz. So a set of 3.5 inch 2x$12=$24 drivers in this double horn cabinet can actually produce a response that almost rivals a $48 FE126EN with smoother coverage over the 200 Hz range, no shoutiness peak at 7 kHz that the Fostex is known for, and giving up a little bit of bass extension which is to be expected when using a dual horn cabinet without really changing the overall length of the horn substantially.
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Sketch of Double Uneaqual Length BLH
This is a sketch of the type of design mod that is required to implement a double uneven length horn. Although not shown, the sims above are for this geometry but somehow with the mouths exiting on the back.
This is a sketch of the type of design mod that is required to implement a double uneven length horn. Although not shown, the sims above are for this geometry but somehow with the mouths exiting on the back.
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Heads up on the BK12M with foam core
I tried making a BK12M with foam core and the FE126en, but it failed pretty miserably because it was so top-heavy. Maybe it would have been okay if it was held upright with some sort of base to keep it from wobbling at the sides, back, and front. The FE126en is fairly heavy though—maybe the weight of two smaller drivers—which wouldn't be a problem with plywood, but foam core is crazy light.
I think I might try 30" * 30" cornus with the FE126en instead, sometime later this year. I think I'd either use 1/4" plywood or double up layers for the front and back if using foam core though.
I tried making a BK12M with foam core and the FE126en, but it failed pretty miserably because it was so top-heavy. Maybe it would have been okay if it was held upright with some sort of base to keep it from wobbling at the sides, back, and front. The FE126en is fairly heavy though—maybe the weight of two smaller drivers—which wouldn't be a problem with plywood, but foam core is crazy light.
I think I might try 30" * 30" cornus with the FE126en instead, sometime later this year. I think I'd either use 1/4" plywood or double up layers for the front and back if using foam core though.
Scottclayton,
That is good to hear someone has tried the BK12M in FC - please post pictures. When you say it failed miserably, it sounds more like a weight/structural issue which can be fixed with a wide outrigger legs, etc. But how did it sound? Was there enough bass enhancement from the horn? I would definitely add a 1/4 in plywood layer on top of the baffle to provide structural support for the heavy driver.
A 30 in cornu with FE126EN would be a neat build - definitely use plywood on baffle - as cheap FC is only available in 20x30 in sizes. You may also look into the half in thick Dow Corning extruded polystyrene foam insulation panels from Home Depot or Lowes. Bcmbob built the DNA horn with that stuff with moderate success. It may make a good Cornu back and front for added structural strength. Still needs some plywood at least around where driver screw holes go.
That is good to hear someone has tried the BK12M in FC - please post pictures. When you say it failed miserably, it sounds more like a weight/structural issue which can be fixed with a wide outrigger legs, etc. But how did it sound? Was there enough bass enhancement from the horn? I would definitely add a 1/4 in plywood layer on top of the baffle to provide structural support for the heavy driver.
A 30 in cornu with FE126EN would be a neat build - definitely use plywood on baffle - as cheap FC is only available in 20x30 in sizes. You may also look into the half in thick Dow Corning extruded polystyrene foam insulation panels from Home Depot or Lowes. Bcmbob built the DNA horn with that stuff with moderate success. It may make a good Cornu back and front for added structural strength. Still needs some plywood at least around where driver screw holes go.
Right, also, another thing that holds true for all speakers until they become truly rigid/massive is to add weight to mass load it to the floor somehow, so temporarily adding a significant amount of weight on top will give you a much better idea of how it really performs, especially if made from a very lossy material.
GM
TB W41320SIF
I have a pair of TB 1320SIF's that didn't work out for a pair of Cornu Spirals. I would like to build a floor standing design like the metronome or frugal horn using foam core laminated with thin plywood. The foam core I get here is 4x8' so height is not too much of an issue.
I don't have a clue as to designing something like this though
Any help would be greatly appreciated
Here are the W4 specs:
I have a pair of TB 1320SIF's that didn't work out for a pair of Cornu Spirals. I would like to build a floor standing design like the metronome or frugal horn using foam core laminated with thin plywood. The foam core I get here is 4x8' so height is not too much of an issue.
I don't have a clue as to designing something like this though
Any help would be greatly appreciated
Here are the W4 specs:
Prez,
The plans for the FH3 inspired foam core horn with Vifa tc9fd are there - you asked for them. If you want to use the TB W4, I think they will probably work well in the standard FH3 plans which call for a 32 in high cabinet that is 5 in wide (internally). For a Met, there may be some existing designs out there you might want to post in the the Met thread. I can highly recommend the FH3 based on my experience with my mini inspired homage with the Vifa.
You might want to check out the plans for the Met for the FE108Sigma, which has very similar T/S parameters but with much more xmax - so close in fact, I can't see why the Fostex is so much more expensive.
They have about the same fs, Sd, Qts, Vas, and Bl, that it would be a good place to start. The plans are here: http://p10hifi.net/FH/download/metronome-FE108eS-1v101-map.pdf
The plans for the FH3 inspired foam core horn with Vifa tc9fd are there - you asked for them.
If you want to use the TB W4, I think they will probably work well in the standard FH3 plans which call for a 32 in high cabinet that is 5 in wide (internally). For a Met, there may be some existing designs out there you might want to post in the the Met thread. I can highly recommend the FH3 based on my experience with my mini inspired homage with the Vifa.You might want to check out the plans for the Met for the FE108Sigma, which has very similar T/S parameters but with much more xmax - so close in fact, I can't see why the Fostex is so much more expensive.
They have about the same fs, Sd, Qts, Vas, and Bl, that it would be a good place to start. The plans are here: http://p10hifi.net/FH/download/metronome-FE108eS-1v101-map.pdf
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Prez,
The plans for the FH3 inspired foam core horn with Vifa tc9fd are there - you asked for them.
well, actually, not that it much affects variations that would be more correctly classified as "inspired by", but internal width of FH3 is 140mm = 5.5" - yes it would make a difference
Prez,
I just built a simulation of the Met on AkAbak to see what the W4-1320SIF might look like. You can't use the FE126EN cabinet - the T/S params are similar but don't translate - probably due to big difference in Qms. Anyhow, below is my sim of the Met with the FE126En (first plot)- not bad. Then I stuck the W4-1320SIF in and not good (second plot). I went and tweaked the cabinet to make it larger and changed the porting to get something reasonable (third plot), with cone displacement (4th plot). So I would be careful in building the Met cabinet as it. The modified cabinet that I have is as follows (in inches multiplied by meters/inch):
Sims with speaker placed 4 ft from back wall 1 watt at 1 meter. I added a little BSC circuit of 3 ohms and 1.2 mH.
I just built a simulation of the Met on AkAbak to see what the W4-1320SIF might look like. You can't use the FE126EN cabinet - the T/S params are similar but don't translate - probably due to big difference in Qms. Anyhow, below is my sim of the Met with the FE126En (first plot)- not bad. Then I stuck the W4-1320SIF in and not good (second plot). I went and tweaked the cabinet to make it larger and changed the porting to get something reasonable (third plot), with cone displacement (4th plot). So I would be careful in building the Met cabinet as it. The modified cabinet that I have is as follows (in inches multiplied by meters/inch):
Code:
Width_top = (3.00 * 0.0254);
Depth_top = (1.00 * 0.0254);
Height = (45.0 * 0.0254);
Width_bot = (11.0 * 0.0254);
Depth_bot = (7.00 * 0.0254);
Leg_Height = (2.0 * 0.0254);
Driver_pos = (18.0 * 0.0254); | Distance from top
| Port depth and length
Port_len = (3.5 * 0.0254);
Port_dia = (3.0 * 0.0254);Sims with speaker placed 4 ft from back wall 1 watt at 1 meter. I added a little BSC circuit of 3 ohms and 1.2 mH.
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Thanks to X!
Another big thanks goes out to X.
Just completed one of his wall mounted designs Using the every popular Vifa 3". The slim wall mount MLTL using a full sheet of 30x20 foamcore for the front and rear baffles.
It's a proven design because I built a split set for my mother and my uncle liked them so much I built him the original plan and covered it with a car print. It's going in his office at his car lot.
Just waiting on the drivers that should be here tomorrow.
Thanks again X
Another big thanks goes out to X.
Just completed one of his wall mounted designs Using the every popular Vifa 3". The slim wall mount MLTL using a full sheet of 30x20 foamcore for the front and rear baffles.
It's a proven design because I built a split set for my mother and my uncle liked them so much I built him the original plan and covered it with a car print. It's going in his office at his car lot.
Just waiting on the drivers that should be here tomorrow.
Thanks again X
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Ryan,
That does not look anything like a speaker! Very nice print for a car shop. I am actually listening to mine right now and they sound fantastic. I have them mounted behind my desk so I switched left/right. This was one of the first FC speakers I ever built. It originally was based on a larger straight duct TL. That sounded OK, but I wanted more bass and when I slapped on the constrictor ports - they became MLTL's and it improved the sound 200%. I am glad you like them - I hope your uncle does too - nice one of a kind present that doesn't cost much but brings big smiles.
One thing that helped tune the stuffing was to mic the ports and measure the bass response. It helped to balance the left and right.
Do you want to try the Met I just designed above, or how about the dual length BLH?
That does not look anything like a speaker! Very nice print for a car shop. I am actually listening to mine right now and they sound fantastic. I have them mounted behind my desk so I switched left/right. This was one of the first FC speakers I ever built. It originally was based on a larger straight duct TL. That sounded OK, but I wanted more bass and when I slapped on the constrictor ports - they became MLTL's and it improved the sound 200%. I am glad you like them - I hope your uncle does too - nice one of a kind present that doesn't cost much but brings big smiles.
One thing that helped tune the stuffing was to mic the ports and measure the bass response. It helped to balance the left and right.
Do you want to try the Met I just designed above, or how about the dual length BLH?
Thanks for the challenge X, but i have to get the boy's rocket speakers ready to fire so to speak. We have them painted, just have to mount the fins on the bottom.
I checked out the double BLH and it just so happens I ordered 8 little vifas when I got my uncles drivers. Maybe over the long weekend............
Thanks Prezden for the kind words.
I checked out the double BLH and it just so happens I ordered 8 little vifas when I got my uncles drivers. Maybe over the long weekend............
Thanks Prezden for the kind words.