Preparing to get BK-16 with FE168FE- advice please?
Want to order BK-16 kit with Sigma FE168EZ driver option- now $716 from Madisound- no freight charge! No tweeters- can't hear that high and doesn't sound like it's needed anyway. All tube gear- current amp is BottleHead Paramount V1.1 with Psvane 300Bs. Currently on Stonewall Jackson, Norma Jean Beasler, Loretta Lynn, Ray Price, Charlie Louvin, Hank Snow binge- all extremely well recorded/engineered. Seems like:
1) no dampening sheets anywhere- just the wooley stuff behind the drivers and dampening mat on magnet and frame?
2) BSC needed?
3) what are the HP difusers mentioned? Where do they go?
4) saw references to different "putty" being recommended- where would this go?
I like the idea of gluing one side together for experimenting before final glueing. Screws used?
Thanks, Kip........
Want to order BK-16 kit with Sigma FE168EZ driver option- now $716 from Madisound- no freight charge! No tweeters- can't hear that high and doesn't sound like it's needed anyway. All tube gear- current amp is BottleHead Paramount V1.1 with Psvane 300Bs. Currently on Stonewall Jackson, Norma Jean Beasler, Loretta Lynn, Ray Price, Charlie Louvin, Hank Snow binge- all extremely well recorded/engineered. Seems like:
1) no dampening sheets anywhere- just the wooley stuff behind the drivers and dampening mat on magnet and frame?
2) BSC needed?
3) what are the HP difusers mentioned? Where do they go?
4) saw references to different "putty" being recommended- where would this go?
I like the idea of gluing one side together for experimenting before final glueing. Screws used?
Thanks, Kip........
That depends. The influence of high frequencies can extend lower down.
Probably; that's for you to determine in your system though.
If you feel inclined. It's not mandatory.
Depends on their position in the room and its acoustics (system response) which only you can determine. Hopefully not. The BK-16 doesn't get particularly low but should have reasonable gain across its operating BW with the 168.
Defunct / discontinued. They were plastic diffusers with a similar hyperbolic paraboloid shape to the ESigma driver range, mainly intended to be placed within the horn's expansion path.
Something of a moot point given that they are no more, but it varied depending on the enclosure and personal taste. Generally they were used a little way back from the terminus as I recall.
Depends on what specifically is being referred to. Sometimes used for filling voids in the horn. At other times used to provide some mass-damping for driver baskets (and to try to help shape the back-wave of the driver).
Not by themselves unless you want chronic leak-paths. With some sealing tape, maybe. Alternatively, get a few packets of Blu-tak or whatever your equivalent thereof may be, roll into long continuous strips (no spaces of any kind: it has to be air-tight) and use that to temporarily fix one side panel in place. You'll actually have a merry dance getting that side panel off as it sticks the thing on quite firmly.
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For temporary sealing of side panels during prototyping / fine tuning of damping/bracing, I've always used a combination of thin closed cell glazing gasket tape and screws. Some guys like to use clamps, but I suspect that their extra mass would effect the enclousure's resonance characteristics, which is one of the things this part of the process is attempting to resolve.
Of course I have no objective measurements to confirm that, and to reiterate one of recent favourite forum quotes -" DIY is all about denial" - in this case that such intuition can't be wrong
Of course I have no objective measurements to confirm that, and to reiterate one of recent favourite forum quotes -" DIY is all about denial" - in this case that such intuition can't be wrong
I assume that after you are happy with the tuning you glue the final side panel on. At that point do you omit the screws and use filler for the holes? I've heard some people like an all-glued final assembly for uniformity in tension of panels I guess.
Also, I will probably go with no dampening fabric on walls- just the Acoustastuff behind the driver- and just go ahead and glue the final side panel on today. But I'm plagued with another question- I'm thinking of putting sand in the lower rear void at the rear bottom of the BK-16. This would be non-reversable. Any opinions thoughts? This is recommended in a lot of the Japanese Nogoaka folded horn DIY instructions.
Yes, once I'm happy enough with the damping fiber, I'll glue up - using the screws again as clamps, then remove and fill with bondo before veneering. If it's a prototype for something that will be run in any kind of volume., I'll note the weight and distribution of fill, and can avoid that step on future builds.
I'd also agree with your thoughts on damping walls. I've used sand or granulated glass blasting media to fill voids on some designs, and depending on their location, it's been possible to machine a large opening add a recessed or even full sized cover plate to facilitate removal of fill. I made a set of floor standing enclosures a few years ago that had an approx 3/4 cu ft void at the bottom that I thought would be an acoustic issue, so I filled them with the glass shot. Guess what, they became rather a bitch to move around, and with a pretty messed up back, staircases were no fun at all.
I'd also agree with your thoughts on damping walls. I've used sand or granulated glass blasting media to fill voids on some designs, and depending on their location, it's been possible to machine a large opening add a recessed or even full sized cover plate to facilitate removal of fill. I made a set of floor standing enclosures a few years ago that had an approx 3/4 cu ft void at the bottom that I thought would be an acoustic issue, so I filled them with the glass shot. Guess what, they became rather a bitch to move around, and with a pretty messed up back, staircases were no fun at all.
I have a set of bk-16's with fe166en drivers and bottlehead s e x amp.
I started with 18 ga stranded internal wire and switched to 22ga magnet wire. I used 3-1/2" risers made from 2x4's, but I have wood laminate floors. I focused on reducing sound coming back through the driver by fluff and felt in the " compression chamber. Try to minimize the stuffing in the "horn". The less you use, the more dynamic it will sound. I also worked on reducing high frequencies from coming out the mouth by using some radiant barrier film (for wrapping a water heater) in the horn path to diffuse the high frequencies.
And I used silicon sealant on all the internal seams.
At first I hated them, but after tweaking they sounded nice and dynamic on the right music.
I started with 18 ga stranded internal wire and switched to 22ga magnet wire. I used 3-1/2" risers made from 2x4's, but I have wood laminate floors. I focused on reducing sound coming back through the driver by fluff and felt in the " compression chamber. Try to minimize the stuffing in the "horn". The less you use, the more dynamic it will sound. I also worked on reducing high frequencies from coming out the mouth by using some radiant barrier film (for wrapping a water heater) in the horn path to diffuse the high frequencies.
And I used silicon sealant on all the internal seams.
At first I hated them, but after tweaking they sounded nice and dynamic on the right music.
Careful with square drive brass screws - it's far easier to snap the heads off than you might think - particularly as small as #6.
Foam carpet underlayment will not likely deliver the same results for this case as a natural fiber matting such as felted denim, jute or cotton upholstery padding.
Foam carpet underlayment will not likely deliver the same results for this case as a natural fiber matting such as felted denim, jute or cotton upholstery padding.
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Chrisb:
I was smart enough to do some trial runs on scrap wood- did break off one of the heads. So I know about how much torque it will take. Wish I could find a good countersink adjustable tapered drill with decent stop for doing these. The Rockler one I have didn't work out so good- kept getting different countersink depths- and marks on the work piece from the stopper. Stopper difficult to adjust.
The carpet underlayment I was talking about is not foam- it is a multi colored felt (or something)- but I haven't found a local source yet. Could you be more specific? Manufacturer, product name, thickness? I tried to order some from England- but they were not able to ship because of some laws they have against shipping small orders (or something).
So my BK-16/FE168 Sigmas are up and running. I have already broken in the Fostex FE168EZ drivers with the "Irrational but Efficacious" "System Enhancement Disc" from Ayre. I am really glad I did this speaker buiuld- definitely a new ball game. Great separation of instruments. Seem to favor instrumental- music with empty spaces between notes. Maybe no so hot for rock. I will be eventually building something for the Altec 604-8Ks I just got. I will post some pictures and more info on my BKs later after work. I can already note improvements as they are breaking in. Very happy- I now realize that my previous speakers were not up to the standards of the rest of my system.
I was smart enough to do some trial runs on scrap wood- did break off one of the heads. So I know about how much torque it will take. Wish I could find a good countersink adjustable tapered drill with decent stop for doing these. The Rockler one I have didn't work out so good- kept getting different countersink depths- and marks on the work piece from the stopper. Stopper difficult to adjust.
The carpet underlayment I was talking about is not foam- it is a multi colored felt (or something)- but I haven't found a local source yet. Could you be more specific? Manufacturer, product name, thickness? I tried to order some from England- but they were not able to ship because of some laws they have against shipping small orders (or something).
So my BK-16/FE168 Sigmas are up and running. I have already broken in the Fostex FE168EZ drivers with the "Irrational but Efficacious" "System Enhancement Disc" from Ayre. I am really glad I did this speaker buiuld- definitely a new ball game. Great separation of instruments. Seem to favor instrumental- music with empty spaces between notes. Maybe no so hot for rock. I will be eventually building something for the Altec 604-8Ks I just got. I will post some pictures and more info on my BKs later after work. I can already note improvements as they are breaking in. Very happy- I now realize that my previous speakers were not up to the standards of the rest of my system.
Todd:
The stuff that is sold for water heaters is about 1 1/2" loft typical housing insulation with reflective foil backing. Is that what you used?
Also, where in the horn path? On the sides all the way thru? Or fronts and backs? Sorry to be a stickler for detail, but I've never done this type of tuning so I don't know where to start. Thanks.........
Thanks Todd.
For now I found some "24oz synthetic fiber pad" at a carpet store down the street (about 1/4" thick). Going to try behind speaker driver and somewhere in back of enclosure. To my brain, seems to me like the foil on the outer side of the Reflectix would complicate things?
I'm getting a lot more search results using term "carpet padding". Eventually want wool felt. McMaster Carr has it, but I'm worried it may be too hard/dense- may be reflective. They have several versions: F10, F13, and F26- gotta figure out which to use.
For now I found some "24oz synthetic fiber pad" at a carpet store down the street (about 1/4" thick). Going to try behind speaker driver and somewhere in back of enclosure. To my brain, seems to me like the foil on the outer side of the Reflectix would complicate things?
I'm getting a lot more search results using term "carpet padding". Eventually want wool felt. McMaster Carr has it, but I'm worried it may be too hard/dense- may be reflective. They have several versions: F10, F13, and F26- gotta figure out which to use.
I completed the BK-16's and installed the broken-in Fostex FE168EZ's. Have been listening for several days and am quite happy. In order to tune, I have not glued the left sides- I drilled a series of countersunk holes for some brass square drive screws. Will be getting some neoprene 7 X 3mm tape to help seal while tuning.
I bought 2 pairs of 2' x 4' x 3/4" MDF boards from Home Depot ($14 ea), and checked them for flatness. To be sure everything stayed flat, I used 2 of the boards stacked as a assembly table. Because I couldn't go outside because of the rain, I used the stove top as a base. As you can see in one of the pictures, I used cinder blocks for compression on the vertical axis while gluing- and Bessey clamps for the horizontal axes. I like the cinder blocks because of the even pressure and quick. On final glueing of the left side, I will place the two other MDF boards on the left side with cinder blocks on top as well.
I wound up with about a 1/8" gap at the bottom of the compression chamber and figured it needed to be well sealed against the small triangular void below it- see picture. So I made wedge-blocks and glued them in (instructions called for use of "tag board"). The angle at the top of the blocks is 10.7 degrees.
I bought a 50lb bag of PlaySand at Home Depot ($4), and baked some in the oven because it was pretty moist. My daughter was pretty amused. Put as much as would fit in a heavy duty ZipLoc bag and stuffed it in the lower triangular void of the BK-16's. I fluffed out and installed some of the AcoustaStuff that came with the kit in some areras of the compression chamber.
Because I also noted the "reverby" nature of the BK's that others have referred to, I am installing 8" X 8" damping pads on the panel behind the drivers- and a circular pad on the back of the driver magnet. Also on the top and front corner of the angled panel at the bottom of the CC. For now, I am using some "24oz synthetic fiber pad" felt. This is used under carpets and is 1/4" thick- it's that stuff that's multicolored and made from new fabric remnants. I think I will be ordering some pure wool felt that is 1/2" thick for final install- not expensive- but comes from England. Is 1/2" too thick? Interfere with the throat of the compression chamber? I am using water based caulking to glue the pads in place- couldn't think of any other way- staple gun won't fit. Caulking should be pretty easy to remove while preparing for final pad install. Trying to get them to sound sharper, crisper.
These have definitely retired my previous favorite speakers (Bowers and Wilkins 805 Nautilus knock-offs). They are winning by a large margin. One of the things I like is that they don't seem directional like most speakers: I noticed very little difference in sound while sitting at a 70 degree angle off the firing line. Also, they sound more musical at low gain levels than any speakers I had. Both of these things are a big deal to me. These are just two details- I also just really like the sound. I think they somewhat favor instrumental recordings with space between the notes. That crazy song, "Barn Dance" by Moon Dog on that cathedral organ- wow. John Cage, Steve Reich. Tame Impala and Neko Case also sounded damn good.
I've never "tuned" speakers before- I'm shooting in the dark based on info in forums. I don't know if the approach I've used is best- just the best I could come up with- just wanted to get them up and running.
Thanks for help, Kip........
I bought 2 pairs of 2' x 4' x 3/4" MDF boards from Home Depot ($14 ea), and checked them for flatness. To be sure everything stayed flat, I used 2 of the boards stacked as a assembly table. Because I couldn't go outside because of the rain, I used the stove top as a base. As you can see in one of the pictures, I used cinder blocks for compression on the vertical axis while gluing- and Bessey clamps for the horizontal axes. I like the cinder blocks because of the even pressure and quick. On final glueing of the left side, I will place the two other MDF boards on the left side with cinder blocks on top as well.
I wound up with about a 1/8" gap at the bottom of the compression chamber and figured it needed to be well sealed against the small triangular void below it- see picture. So I made wedge-blocks and glued them in (instructions called for use of "tag board"). The angle at the top of the blocks is 10.7 degrees.
I bought a 50lb bag of PlaySand at Home Depot ($4), and baked some in the oven because it was pretty moist. My daughter was pretty amused. Put as much as would fit in a heavy duty ZipLoc bag and stuffed it in the lower triangular void of the BK-16's. I fluffed out and installed some of the AcoustaStuff that came with the kit in some areras of the compression chamber.
Because I also noted the "reverby" nature of the BK's that others have referred to, I am installing 8" X 8" damping pads on the panel behind the drivers- and a circular pad on the back of the driver magnet. Also on the top and front corner of the angled panel at the bottom of the CC. For now, I am using some "24oz synthetic fiber pad" felt. This is used under carpets and is 1/4" thick- it's that stuff that's multicolored and made from new fabric remnants. I think I will be ordering some pure wool felt that is 1/2" thick for final install- not expensive- but comes from England. Is 1/2" too thick? Interfere with the throat of the compression chamber? I am using water based caulking to glue the pads in place- couldn't think of any other way- staple gun won't fit. Caulking should be pretty easy to remove while preparing for final pad install. Trying to get them to sound sharper, crisper.
These have definitely retired my previous favorite speakers (Bowers and Wilkins 805 Nautilus knock-offs). They are winning by a large margin. One of the things I like is that they don't seem directional like most speakers: I noticed very little difference in sound while sitting at a 70 degree angle off the firing line. Also, they sound more musical at low gain levels than any speakers I had. Both of these things are a big deal to me. These are just two details- I also just really like the sound. I think they somewhat favor instrumental recordings with space between the notes. That crazy song, "Barn Dance" by Moon Dog on that cathedral organ- wow. John Cage, Steve Reich. Tame Impala and Neko Case also sounded damn good.
I've never "tuned" speakers before- I'm shooting in the dark based on info in forums. I don't know if the approach I've used is best- just the best I could come up with- just wanted to get them up and running.
Thanks for help, Kip........
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I'm waiting for some 100% wool 1/2" damping felt- also have 7mm 80/20 wool cotton blend. May try putting on front and back horn interior (not sides) except for final opening. One poster earlier in this thread I think claims to have success with that. Also, in info I got from Tang Band on their Nagaoka design, they recommend this in 7mm (1/4").
Currently am using small amount of "24oz synthetic fiber pad" (1/4") carpet underlay in compression chamber (see picture). Seems to be helping.
ChrisB: you were so right about the brass screws- I like the look of the brass- and I thought I might be leaving them in, so I tried them. Dumb idea- break too easy and complicated to pre drill. And I have decided I will not be using the screws in final assembly. But I will be assembling/disassembling many times trying to tune, so the brass is very impractical. First thought: drywall screws (square drive). Anyone have screw favorites or preferences?
Scottmoose:
I think I will try tweeters- Fostex T90A. My hearing is a little better than I thought....
Currently am using small amount of "24oz synthetic fiber pad" (1/4") carpet underlay in compression chamber (see picture). Seems to be helping.
ChrisB: you were so right about the brass screws- I like the look of the brass- and I thought I might be leaving them in, so I tried them. Dumb idea- break too easy and complicated to pre drill. And I have decided I will not be using the screws in final assembly. But I will be assembling/disassembling many times trying to tune, so the brass is very impractical. First thought: drywall screws (square drive). Anyone have screw favorites or preferences?
Scottmoose:
I think I will try tweeters- Fostex T90A. My hearing is a little better than I thought....
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