OzMikeH said:
One of Tony's 1st efforts.
An externally hosted image should be here but it was not working when we last tested it.
dave
Thanks Dave for posting that picture.
Actually that was my first full-range "get-your-feet-wet" multi-layered project.
Even before that, I built this layered sub
see this post: http://fullrangedriver.com/forum/viewtopic.php?id=207
this is the layered 12" sub, 4" flared port with 1/2" polycarbonate plastic on front & back & Parts Express speaker cabinet carpet I completed back in ~ 1999-2000
16 layers of 1" MDF, walls were average about 1.25" thick
IF the sides were to be clear, probably absolute minimum of 3/4" acrylic. The only problem that I found with this is the visual appearance of the screws exposed
This is a sample piece of the 3/4" Europly 15-ply material:
Vacuum hold-down was simply not enough to secure each layer firmly for CNC machining. Painful to screw in then remove, but well worth the effort.
Plywood was a challange for me to cut cleanly without destroying the skin off, top & bottom. I used a solid carbide, 3/8" compression end-mill, 3 passes, finish depth of .78"
BTW, forgot to mention that all the wall thickness (offset) modified to 1"
Tony
Actually that was my first full-range "get-your-feet-wet" multi-layered project.
Even before that, I built this layered sub
see this post: http://fullrangedriver.com/forum/viewtopic.php?id=207
An externally hosted image should be here but it was not working when we last tested it.
this is the layered 12" sub, 4" flared port with 1/2" polycarbonate plastic on front & back & Parts Express speaker cabinet carpet I completed back in ~ 1999-2000
16 layers of 1" MDF, walls were average about 1.25" thick
An externally hosted image should be here but it was not working when we last tested it.
IF the sides were to be clear, probably absolute minimum of 3/4" acrylic. The only problem that I found with this is the visual appearance of the screws exposed
This is a sample piece of the 3/4" Europly 15-ply material:
An externally hosted image should be here but it was not working when we last tested it.
Vacuum hold-down was simply not enough to secure each layer firmly for CNC machining. Painful to screw in then remove, but well worth the effort.
Plywood was a challange for me to cut cleanly without destroying the skin off, top & bottom. I used a solid carbide, 3/8" compression end-mill, 3 passes, finish depth of .78"
An externally hosted image should be here but it was not working when we last tested it.
BTW, forgot to mention that all the wall thickness (offset) modified to 1"
An externally hosted image should be here but it was not working when we last tested it.
Tony
>How many sheets?
So far I used 4 sheets, still tinkering with this first prototype design so I still need about another sheet for the sides
I might redo the to straight rear deflector instead of the curved one (still layered for mass-loading); will post a picture of this curved one later...
So far I used 4 sheets, still tinkering with this first prototype design so I still need about another sheet for the sides
I might redo the to straight rear deflector instead of the curved one (still layered for mass-loading); will post a picture of this curved one later...
First, Layertone, thanks for the photos. That's a truely amazing project you have going. I wish you the best.
Now onto my Frugel-Horns: I finally finished the deflectors and got everything put together, but something started troubling me about the sound. I went to great effort to get them to measure flat in-room, but the vocals sounded wrong, sort of muted and flat. After two weeks of trying various things I finally increased the volume in the CC behind the driver and took out the small amount of stuffing in the line. I also got rid of the notch filter. Ah yes, much better. The vocals now sound like vocals again. There is a depth to them that was lacking before. It was sort of like the difference between talking in a monotone and talking in a regular voice. I'm a lot happier now with how they sound. The funny thing now is that they measure much worse in-room but sound so much better. Go figure.
The whole problem was apparently with the CC volume and suprabaffle size. My original prototype used a 11 1/2" square suprabaffle while the final build was 12 5/8". Apparently this changed everything. Removing 7.8 cubic inches from the CC brought everything back into balance. Since I had to modify by removing quite a bit of material from the driver mounting hole when I changed how the suprabaffle was mounted, I cannot say exactly what the volume of the CC is now. I think it's around 119-120 cubic inches and may be a bit larger but certainly not smaller. So I'm now happy as a can be with the sound. It's been a great project.
Final specs: Wedgie version:
Driver: Fostex FE108EZ
Cabinet: 3/4" plywood (not BB) with 1/2" BB interior and wrapped in 1/8" quartersawn oak ply, glued with contact cement. The overall cabinet width is 1/4" wider and 1/8" taller than the plans indicate due to the 1/8" plywood. All voids filled with cat litter.
Deflector: Height 25". 3/4" particle board wrapped in 1/8" oak, solid oak top. Filled with cat litter. In-room measurements confirm that these add a few dB at the lowest octave. I can't say they are absolutely necessary, but they don't hurt. It would depend on your room. If you have corners, you could live without them without missing anything.
Finish: Wood: Renissance wax. MDF: Semi-gloss black lacquer.
Suprabaffle: 1" and 3/4" MDF 12 5/8" x 12 5/8" x 3 3/4", beveled four sides and rounded (see photo below). Attached only with silicone caulk.
Compression Chamber: At least 119-120 cubic inches and perhaps up to 125. My conclusion at this point is the wider the suprabaffle, the bigger the CC needs to be, at least for this driver.
Speaker weight: Heavy!
Doug
The final photo:
Now onto my Frugel-Horns: I finally finished the deflectors and got everything put together, but something started troubling me about the sound. I went to great effort to get them to measure flat in-room, but the vocals sounded wrong, sort of muted and flat. After two weeks of trying various things I finally increased the volume in the CC behind the driver and took out the small amount of stuffing in the line. I also got rid of the notch filter. Ah yes, much better. The vocals now sound like vocals again. There is a depth to them that was lacking before. It was sort of like the difference between talking in a monotone and talking in a regular voice. I'm a lot happier now with how they sound. The funny thing now is that they measure much worse in-room but sound so much better. Go figure.
The whole problem was apparently with the CC volume and suprabaffle size. My original prototype used a 11 1/2" square suprabaffle while the final build was 12 5/8". Apparently this changed everything. Removing 7.8 cubic inches from the CC brought everything back into balance. Since I had to modify by removing quite a bit of material from the driver mounting hole when I changed how the suprabaffle was mounted, I cannot say exactly what the volume of the CC is now. I think it's around 119-120 cubic inches and may be a bit larger but certainly not smaller. So I'm now happy as a can be with the sound. It's been a great project.
Final specs: Wedgie version:
Driver: Fostex FE108EZ
Cabinet: 3/4" plywood (not BB) with 1/2" BB interior and wrapped in 1/8" quartersawn oak ply, glued with contact cement. The overall cabinet width is 1/4" wider and 1/8" taller than the plans indicate due to the 1/8" plywood. All voids filled with cat litter.
Deflector: Height 25". 3/4" particle board wrapped in 1/8" oak, solid oak top. Filled with cat litter. In-room measurements confirm that these add a few dB at the lowest octave. I can't say they are absolutely necessary, but they don't hurt. It would depend on your room. If you have corners, you could live without them without missing anything.
Finish: Wood: Renissance wax. MDF: Semi-gloss black lacquer.
Suprabaffle: 1" and 3/4" MDF 12 5/8" x 12 5/8" x 3 3/4", beveled four sides and rounded (see photo below). Attached only with silicone caulk.
Compression Chamber: At least 119-120 cubic inches and perhaps up to 125. My conclusion at this point is the wider the suprabaffle, the bigger the CC needs to be, at least for this driver.
Speaker weight: Heavy!
Doug
The final photo:
Attachments
Taperwood said:
Lovely... really nice looking too
The general rule is that a larger sB pushes the frequency of BS onset down, which would need to be compensated for by increasing CC size as this reduces the frequency of the low pass filter formed by the CC & the throat.
The data points you have established will be very useful. Do send me some more pictures for the gallery.
dave
planet10 said:
Lovely... really nice looking too
The general rule is that a larger sB pushes the frequency of BS onset down, which would need to be compensated for by increasing CC size as this reduces the frequency of the low pass filter formed by the CC & the throat.
The data points you have established will be very useful. Do send me some more pictures for the gallery.
dave
Thanks all. Dave, what, in theory, would happen if I reduced the throat size vis-a vis the suprabaffle and CC size? Or is the throat size too fundamental to the design to mess with? I'm just curious.
I'm trying to understand all this. It kind of makes sense, but it's like thinking in 3D. Baffle step, frequency wavelengths, half space, secondary harmonics, Yikes! It's still hard to fully grasp.
One thing I noticed is that it seems the speaker's efficiency went up. The volume knob is now lower on the amp before my wife tells me to turn it down
, and it does seem to play louder.Doug
Scottmoose said:
Thanks, Scott. I should note that the changes in the FR were dips, not peaks, so now the curve is more wavy than shaped like an m. Also, they now sound much better at lower volumes (around 70 dB), which is where I do a lot of listening, so I assume I did something affecting the Fletcher-Munson curve.
If I regularly played music at 85-90 dB, I assume I would have to redo the CC volume. In fact, I might slowly add 1 cubic inch blocks back in to see if I can fine-tune the sound. I lost a few dB in the lowest octave and added a few dB between 250 and 500 with this latest change. I would like to see exactly where it starts losing the vocals.
Doug
colonelkernel8 said:
There would no doubt be a difference (and it certainly looks way cool). Till you got them side by side you wouldn't know how much, but the curves would certainly lessen the possible muffling effect of the folding. Perhaps you would increase efficiency in ways you might not expect. I'd love to compare the two.
In a mind's eye experiment, I would think the relative tightness or openness of the wrap would have the greatest effect on how mids and lows went through the horn. I bet if the horn were straight, instead of folded you'd hear a HECK of difference, but that probably wouldn't make a very pretty cabinet.
Course, that's in the mind only. Until I glue on the sides and wire up the drivers from my recently acquired flat paks, it's all armchair talk from this dude (frugel horns in progress).
Karl
Hi Karl
I have been somewhat lackluster following this thread. Did you end up with the flat packs and what driver are you using?
I am very interested in your build, tweaks and what you think of them.
I added supertweeters to mine ( mostly because of the room)
the tweeters were cheaper than cheap from a garage sale.
I still really enjoy them and at the moment would only build something else only because I like to build.
They are still waiting on a better placement but still give me great sound.
Gex
PS Boy! you guys build some nice stuff. I gotta get me some more tools!
I have been somewhat lackluster following this thread. Did you end up with the flat packs and what driver are you using?
I am very interested in your build, tweaks and what you think of them.
I added supertweeters to mine ( mostly because of the room)
the tweeters were cheaper than cheap from a garage sale.
I still really enjoy them and at the moment would only build something else only because I like to build.
They are still waiting on a better placement but still give me great sound.
Gex
PS Boy! you guys build some nice stuff. I gotta get me some more tools!