I just simulated the Eminence Legend 875 (parameters at Spectrumaudio) in a really big BIB (mouth 6xSd) with the TL offset driver sheet and it seems to work (almost 30Hz) without corner loading, clearly better matching bass than typical high-Vas 8"ers. Do the later sheets tell something else?
Greets, Oliver
Greets, Oliver
Thanks Ray.
However, from the scaled drawing of Lovechild posted at zillaspeak.com, it appears that L=Length takes the mid path between the Front baffle and the oblique Centre baffle, stops and takes the mid point of Front/Bottom/Back and then runs vertically up, again from the midpoint between Centre baffle-bottom end and Back baffle.
I haven't done my math, but does your enclosure height of 128/2=64" actually give you a measured Length of 28"? And what about subtracting the thickness of the Centre baffle for the calculation of Sm, which means your enclosure will end up being a wee bit deeper?
I am raising these questions so that I get the enclosure theoretically correct!!
Since you are already playing music through your BIBs, how is the bass loading off the ceiling; do you think raising the open end of the BIB a couple of feet closer to the ceiling (perhaps, with ELF subs or other means) and tapering off the open end from front to back, so as to open the horn opening a bit more, will be further enhancements?
However, from the scaled drawing of Lovechild posted at zillaspeak.com, it appears that L=Length takes the mid path between the Front baffle and the oblique Centre baffle, stops and takes the mid point of Front/Bottom/Back and then runs vertically up, again from the midpoint between Centre baffle-bottom end and Back baffle.
I haven't done my math, but does your enclosure height of 128/2=64" actually give you a measured Length of 28"? And what about subtracting the thickness of the Centre baffle for the calculation of Sm, which means your enclosure will end up being a wee bit deeper?
I am raising these questions so that I get the enclosure theoretically correct!!
Since you are already playing music through your BIBs, how is the bass loading off the ceiling; do you think raising the open end of the BIB a couple of feet closer to the ceiling (perhaps, with ELF subs or other means) and tapering off the open end from front to back, so as to open the horn opening a bit more, will be further enhancements?
Sam:
I identify with your concerns regarding cabinet size and conveyed same to Scottmoose when I was preparing to build mine. Scroll back several pages to post #459 and review the dialog.
Hopefully I will mount the drivers tonight but I first must finish installing the bases. Almost there but no music .....yet.
Proximity to the ceiling as well as altering the shape of the mouth also has been discussed. GM and others gave these points a good airing. Check past posts for details.
Ray
I identify with your concerns regarding cabinet size and conveyed same to Scottmoose when I was preparing to build mine. Scroll back several pages to post #459 and review the dialog.
Hopefully I will mount the drivers tonight but I first must finish installing the bases. Almost there but no music .....yet.
Proximity to the ceiling as well as altering the shape of the mouth also has been discussed. GM and others gave these points a good airing. Check past posts for details.
Ray
Ray Collins,
Yes the closed end. Unfortunately it rained today so I didn't get any work done.
The closed end is what I called the tip.
Earlier in the thread, it was brought up that there were too many high frequencies coming from the terminus. GM and I talked about this. In the thread he wrote that dampening needs to be outside of the enclosure as to not decrease gain and the low frequencies. What he explained to me was that adding stuffing significantly decreases the low frequencies especially as you go down the line. At the tip of the closed end is what can decrease the high frequencies the most, after that, you begin to decrease the low frequencies. Therefore to filter out high frequencies, not much stuffing can be added to the line, so the BIB can be floorloaded. In most listening rooms there is carpet, which should do a good job of decreasing high frequencies coming to the listener. Also he suggested covering the back of the driver with something similar toe grill cloth. As grill cloth can easily cut down high frequencies going through it, enough of it on the back of the driver would not allow high frequencies to ender the line.
GM tell me if my interpretation is incorrect in any way.
Samuel Jayaraj,
Godzilla explains how to design the enclosure from the specs in post 303
Josh
Yes the closed end. Unfortunately it rained today so I didn't get any work done.
The closed end is what I called the tip.
Earlier in the thread, it was brought up that there were too many high frequencies coming from the terminus. GM and I talked about this. In the thread he wrote that dampening needs to be outside of the enclosure as to not decrease gain and the low frequencies. What he explained to me was that adding stuffing significantly decreases the low frequencies especially as you go down the line. At the tip of the closed end is what can decrease the high frequencies the most, after that, you begin to decrease the low frequencies. Therefore to filter out high frequencies, not much stuffing can be added to the line, so the BIB can be floorloaded. In most listening rooms there is carpet, which should do a good job of decreasing high frequencies coming to the listener. Also he suggested covering the back of the driver with something similar toe grill cloth. As grill cloth can easily cut down high frequencies going through it, enough of it on the back of the driver would not allow high frequencies to ender the line.
GM tell me if my interpretation is incorrect in any way.
Samuel Jayaraj,
Godzilla explains how to design the enclosure from the specs in post 303
Josh
An externally hosted image should be here but it was not working when we last tested it.
hello all,
after about 100 hours on the fostex fe108ez i'm starting to hear some more extended bass. just played bela fleck's "flight of the cosmic hippos" and there is a LOT of bass filling the room. i'm not sure how many hours the drivers have in total because i picked them up used from a hornshoppe owner. they appear to be treated with something (damar?) but look new.
a question for the experts -- how does the beyma 8bx look as a bib candidate? i'm not even sure if it qualifies as a fullranger but the guy at the local electronics shop told me it was a really nice driver. not as cheap as the pair of 8ag/n i have sitting on the shelf, but not terribly expensive at about 85 euros.
larry
after about 100 hours on the fostex fe108ez i'm starting to hear some more extended bass. just played bela fleck's "flight of the cosmic hippos" and there is a LOT of bass filling the room. i'm not sure how many hours the drivers have in total because i picked them up used from a hornshoppe owner. they appear to be treated with something (damar?) but look new.
a question for the experts -- how does the beyma 8bx look as a bib candidate? i'm not even sure if it qualifies as a fullranger but the guy at the local electronics shop told me it was a really nice driver. not as cheap as the pair of 8ag/n i have sitting on the shelf, but not terribly expensive at about 85 euros.
larry
Scottmoose,
I got quite a bit of work done on my BIB, unfortunately also cracked the last piece of wood that I was cutting. I seem to be spending most of my time on asthetics, but I've designed the BIB so that I can remove the "supra-baffle" and replace it, also hooks are to be mounted on the inside screws that mount the supra-baffle, so that I can try using grill cloth. I will post my progress and pictures on my website.
Thanks,
Josh
edit: it is also a golden ratio
I got quite a bit of work done on my BIB, unfortunately also cracked the last piece of wood that I was cutting. I seem to be spending most of my time on asthetics, but I've designed the BIB so that I can remove the "supra-baffle" and replace it, also hooks are to be mounted on the inside screws that mount the supra-baffle, so that I can try using grill cloth. I will post my progress and pictures on my website.
Thanks,
Josh
edit: it is also a golden ratio
I have quite a bit more work to do, but here it is so far. More pictures on my website.
Thanks,
Josh
Thanks,
Josh
An externally hosted image should be here but it was not working when we last tested it.
Thanks for the compliments.
by the way, the supra-baffle is some extra plywood from a subwoofer I built for a friend, this is before sanding and finishing.
I worked today and am working tomorrow so I can't finish these speakers until I get back from Spain on the 29th. But I am going to make a few more asthetic changes so they they look a little bit better, before I roundover and paint.
Thanks,
Josh
by the way, the supra-baffle is some extra plywood from a subwoofer I built for a friend, this is before sanding and finishing.
I worked today and am working tomorrow so I can't finish these speakers until I get back from Spain on the 29th. But I am going to make a few more asthetic changes so they they look a little bit better, before I roundover and paint.
Thanks,
Josh
An externally hosted image should be here but it was not working when we last tested it.
I have a question about construction, but it requires some setup...
I've been thinking of doing almost exactly the same thing for a pair of Fostex FE127E that I have so I can compare the BIB to the folded pipes I'm building now.
When I built my pipes, I found it very hard to get the pieces to line up exactly. When I clamped, the glue was slippery enough to cause the pieces to move slightly. When I removed the clamps, I noticed places that aren't exactly lined up.
I noticed in the picture the front and back pieces have quite a pronounced lip prodruding out from the sides. In addition, the top seems to be inset on all four sides.
Did you oversize these pieces on purpose so you can remove the lip with a router (or some other method)?
I was thinking of doing this when I build cabinets in the future, but wasn't sure if it was a common strategy or how well it worked.
I've been thinking of doing almost exactly the same thing for a pair of Fostex FE127E that I have so I can compare the BIB to the folded pipes I'm building now.
When I built my pipes, I found it very hard to get the pieces to line up exactly. When I clamped, the glue was slippery enough to cause the pieces to move slightly. When I removed the clamps, I noticed places that aren't exactly lined up.
I noticed in the picture the front and back pieces have quite a pronounced lip prodruding out from the sides. In addition, the top seems to be inset on all four sides.
Did you oversize these pieces on purpose so you can remove the lip with a router (or some other method)?
I was thinking of doing this when I build cabinets in the future, but wasn't sure if it was a common strategy or how well it worked.
Depending on how I butt my joints I always over cut specific pieces in specific places. For example the sides are 6.5" with the front and back butts on top of the 6.5", making internal depth 6.5". The sides were cut exactly 6.5" wide, but the board was cut a little long so that after all gluing I can use my flush trim router bit to make the joints perfect.
Basically on my first pair of speaker I did the opposite. I cut pieces that weren't quite long enough so they wouldn't be flush with all the other pieces. At that point I decided I would rather use my router or sand the little piece down, then but lots of putty, which looks awful if using plywood.
The piece that you want cut exactly and glued exactly is the taper. I use only glue and clamps, and after a while I will add some liquid nail to ensure air tight joints. My suggestion is for the internal taper glue and clamp. Keep the clamps on there for about 30 minutes, but liquid nail on the joints, leave clamped for 10 minutes, then work on the next one. The pieces won't have moved. Liquid Nails dries quickly.
Thanks,
Josh
Basically on my first pair of speaker I did the opposite. I cut pieces that weren't quite long enough so they wouldn't be flush with all the other pieces. At that point I decided I would rather use my router or sand the little piece down, then but lots of putty, which looks awful if using plywood.
The piece that you want cut exactly and glued exactly is the taper. I use only glue and clamps, and after a while I will add some liquid nail to ensure air tight joints. My suggestion is for the internal taper glue and clamp. Keep the clamps on there for about 30 minutes, but liquid nail on the joints, leave clamped for 10 minutes, then work on the next one. The pieces won't have moved. Liquid Nails dries quickly.
Thanks,
Josh
of possible interest
This tip was posted by Bill Epstein about clamp creep
some time back:
http://audioroundtable.com/Craftsmen/messages/832.html
This tip was posted by Bill Epstein about clamp creep
some time back:
http://audioroundtable.com/Craftsmen/messages/832.html