planet10 said:
The PRINTSCREEN button is your friend. Often labled "Print/Scrn". Just push the button and whatever is on your screen (all of it) will be copied to the clipboard. You can then paste it into any program that will paste graphics. You can crop and do whatever you need there. Bob's your Uncle!!
Useful.
BIB and Frugels sound very different, so it's like comparing a Bentley with an Aston Martin. The BIB has somewhat better bass extension and handling of dynamics, and it throws a somewhat larger image, at the price of more ripple in the response. The object is actually not to allow too much of the midrange information out through the terminus -that's why there's the damping material on the base of the horn. Doesn't completely kill it, but reduces it. If you want total pin-point imaging though, a la a small sealed monitor, the Frugel will be a better bet.
Lining is good. GM prefers it to stuffing I believe. The BIB's flare is a steep one, which is useful. As I understand it (please correct my errors Greg) he suggests lining the front of the sloping baffle, and one side-wall down to just below the driver height, and either some more damping material on the floor, or a very lossy material for the floor.
BIB and Frugels sound very different, so it's like comparing a Bentley with an Aston Martin. The BIB has somewhat better bass extension and handling of dynamics, and it throws a somewhat larger image, at the price of more ripple in the response. The object is actually not to allow too much of the midrange information out through the terminus -that's why there's the damping material on the base of the horn. Doesn't completely kill it, but reduces it. If you want total pin-point imaging though, a la a small sealed monitor, the Frugel will be a better bet.
Lining is good. GM prefers it to stuffing I believe. The BIB's flare is a steep one, which is useful. As I understand it (please correct my errors Greg) he suggests lining the front of the sloping baffle, and one side-wall down to just below the driver height, and either some more damping material on the floor, or a very lossy material for the floor.
Scottmoose said:
Greets!
Works for me! FYI, Bert Doppenberg of Oris horn fame arrived at this damping scheme for his ML-Voigt apparently based on listening tests since it defies 'conventional wisdom', so may be worth experimenting with.........
GM
Attachments
Actually, that looks pretty sensible, with the 2nd side of the baffle lined probably due to the 2nd driver at a 45 degree angle firing into the line. Maybe a little OTT, but I bet it damps the thing well!
Greg -been thinking (I know, I know. Never a good sign). What do you reckon the results would be like from a cabinet like this constructed out of a suitable gauge of high-qaulity steel or similar? By my guestimation, that should make it extremely rigid, and probably reduce panel resonances to a miniscule level, at least in the passband.
Greg -been thinking (I know, I know. Never a good sign). What do you reckon the results would be like from a cabinet like this constructed out of a suitable gauge of high-qaulity steel or similar? By my guestimation, that should make it extremely rigid, and probably reduce panel resonances to a miniscule level, at least in the passband.
Hi Scott,
I know you directed the question for Greg, but... what effect would all that steel have on the dynamics of the driver, with the magnets and all, I know it would be hard to measure but, I would imagine the influence would be there. Especially since we can hear the differences between cables and all.
May be concrete would be better? or some other magnetically inert material... I could be talking out my @#$$ though.
Stroop
I know you directed the question for Greg, but... what effect would all that steel have on the dynamics of the driver, with the magnets and all, I know it would be hard to measure but, I would imagine the influence would be there. Especially since we can hear the differences between cables and all.
May be concrete would be better? or some other magnetically inert material... I could be talking out my @#$$ though.
Stroop
Greets!
Arg!
I forgot about the second driver! This pipe originally used only a single driver, but in looking around I can't find the original damping scheme. 
Anyway, WRT 'conventional wisdom', I was referring to damping a surface opposite a damped sloping one, yet not damping one of the opposing parallel surfaces on the bottom half of the pipe.
Sheet metal or any other super rigid material is preferred for any speaker system with a Q lower than ~0.5 - 1.414 depending on who you talk to and/or where acoustic pressure is high. The inventors of high performance sound systems didn't make them from sheet metal, metal castings, and/or marine grade plywood to save money!
GM
Arg!
I forgot about the second driver! This pipe originally used only a single driver, but in looking around I can't find the original damping scheme. Anyway, WRT 'conventional wisdom', I was referring to damping a surface opposite a damped sloping one, yet not damping one of the opposing parallel surfaces on the bottom half of the pipe.Sheet metal or any other super rigid material is preferred for any speaker system with a Q lower than ~0.5 - 1.414 depending on who you talk to and/or where acoustic pressure is high. The inventors of high performance sound systems didn't make them from sheet metal, metal castings, and/or marine grade plywood to save money!
GM
stroop said:
Greets!
Not sure, but aluminum and cold rolled steel (CRS) didn't have any measurable effect on the various cast and/or welded up cabs I tried other than subjectively maximizing electro-mechanical to acoustic efficiency (should in theory show up on a waterfall or impulse response plot, if measurable) and the latter has the added advantage of acting as an effective shield for even the most powerful ceramic motors available in the '80s.
Yes, concrete, slate, granite, or similar will work as long as their thickness is sufficient to drop its Fs below the lowest desired frequency, which for a large sealed sub means forklift moving heavy at minimum. OTOH, 'light' concrete, typical granite, etc., floor tiles works well on mids - up.
GM
Barium's pretty toxic...
I was a little surprised to do a web search and find that this is actually a product. Barium is a nasty nasty toxin. While there are ways to immobilize it, and I'll bet the vinyl itself isn't too dangerous to work with, when you'd dump those speakers they'd be hazardous waste.
And I certainly wouldn't want to be around if they caught fire!
Don't know whether barium impregnated vinyl would work or not, but I'd try something (anything) else & be friendly to the earth
wixy said:
I was a little surprised to do a web search and find that this is actually a product. Barium is a nasty nasty toxin. While there are ways to immobilize it, and I'll bet the vinyl itself isn't too dangerous to work with, when you'd dump those speakers they'd be hazardous waste.
And I certainly wouldn't want to be around if they caught fire!
Don't know whether barium impregnated vinyl would work or not, but I'd try something (anything) else & be friendly to the earth
Doing a/b comparisons on a bib and an mltl I've heard
quite a few deficiencies at this stage of the bib tweaking.
There's still quite a bit of honking compared to the
sharpness of the mltl.
I have not got the 'floor' of the BIB disassembled yet
to correct.
But what I did do was take some squares of pillow
stuffing about 10" and line the top of the mouth
with four of these and attached with some doublestick tape.
This seems to have cut down on the 'hollowness' from
the line length.
What I'm wondering is: would felt squares be good for a
more permanent treatment? I'm trying to get away
from disassembly to do more lining.
I also took off the suprabaffle because it was making me
unhappy. Whether it's a good idea or not, I prefer to
use some sort of fabric grilles to finish the project as
a permanent part of my listening area. The suprabaffle
made a grill treatment very problematic.
I may come back to that. Jeff's (Godzilla's) wide board
front treatment might be a solution for it.
quite a few deficiencies at this stage of the bib tweaking.
There's still quite a bit of honking compared to the
sharpness of the mltl.
I have not got the 'floor' of the BIB disassembled yet
to correct.
But what I did do was take some squares of pillow
stuffing about 10" and line the top of the mouth
with four of these and attached with some doublestick tape.
This seems to have cut down on the 'hollowness' from
the line length.
What I'm wondering is: would felt squares be good for a
more permanent treatment? I'm trying to get away
from disassembly to do more lining.
I also took off the suprabaffle because it was making me
unhappy. Whether it's a good idea or not, I prefer to
use some sort of fabric grilles to finish the project as
a permanent part of my listening area. The suprabaffle
made a grill treatment very problematic.
I may come back to that. Jeff's (Godzilla's) wide board
front treatment might be a solution for it.
Greets!
IIRC this is the high Fp FE127E MLTL. If so, you won't get the same 'snap' in a BIB due to its much larger Vb, lower Fp mass loading the driver. The BIB should be subjectively more 'live' (accurate) sounding though due to reproducing more of the fundamentals of the harmonics that gives the MLTL its artificially high 'snap' factor.
WRT its hollow sound, the materials used have a lot to do with it and IIRC you like to use paper veneered MDF shelving, which when energized requires much more damping/bracing than if made with a more rigid material, so this drains away more of the driver's 'snap' just like overstuffing a sealed or vented cab does, only worse since we're relying on the pipe to fill in so much missing BW.
Anyway, as has been stated seemingly thousands of times on as many threads and with as many authors, damping to taste is so subjective that only you can decide, especially since IIRC your MLTLs have no damping at all, which would be way too resonant for me to live with, so any suggestion I make would probably unacceptably overdamp it.
That said, if you have/can get long enough real felt (not foam or re-bond) carpet underlayment scraps, cutting them long enough and wide enough to suspend them diagonally from corner to corner all the way from the mouth to the bottom might work. Done this way it damps all sides and rolls off any Fp peaking that may be excessively energizing the room.
GM
IIRC this is the high Fp FE127E MLTL. If so, you won't get the same 'snap' in a BIB due to its much larger Vb, lower Fp mass loading the driver. The BIB should be subjectively more 'live' (accurate) sounding though due to reproducing more of the fundamentals of the harmonics that gives the MLTL its artificially high 'snap' factor.
WRT its hollow sound, the materials used have a lot to do with it and IIRC you like to use paper veneered MDF shelving, which when energized requires much more damping/bracing than if made with a more rigid material, so this drains away more of the driver's 'snap' just like overstuffing a sealed or vented cab does, only worse since we're relying on the pipe to fill in so much missing BW.
Anyway, as has been stated seemingly thousands of times on as many threads and with as many authors, damping to taste is so subjective that only you can decide, especially since IIRC your MLTLs have no damping at all, which would be way too resonant for me to live with, so any suggestion I make would probably unacceptably overdamp it.
That said, if you have/can get long enough real felt (not foam or re-bond) carpet underlayment scraps, cutting them long enough and wide enough to suspend them diagonally from corner to corner all the way from the mouth to the bottom might work. Done this way it damps all sides and rolls off any Fp peaking that may be excessively energizing the room.
GM
I'm trying to work out how high my cabinet should be.
Should it be worked out exactly as pictured here: http://www.zillaspeak.com/bib-howtobuild.asp
Or the height just the line length divided by 2?
Should it be worked out exactly as pictured here: http://www.zillaspeak.com/bib-howtobuild.asp
Or the height just the line length divided by 2?
Yes, no and maybe
Ok, I see how the Bib will be a 'fuller' sound than the
MLTL.
But no, you are mistaken about my BIB build.
The laminated shelving is not laminated on the
surface with a wood grain print, but is laminated
butcher block style as in edge gluing on bare wood.
Those are the 2 sides. The front, divider and back
are particle board which, according to what was said
earlier give a lossy quality which is good. This is
also bare with no surface treatments.
Lastly, the curtain wall idea sounds cool. Maybe
it could be suspended by a piece of wood or sandwiched
between 2 strips and hung freely to turn this way
and that at the diagonal corners.
I'm wondering if the felt would be square like a
curtain or have to cut triangularly looking like a
pennant.
[hope this post goes through-- I made my answer
5 hours ago but the post never showed. :-/
GM said:
Ok, I see how the Bib will be a 'fuller' sound than the
MLTL.
But no, you are mistaken about my BIB build.
The laminated shelving is not laminated on the
surface with a wood grain print, but is laminated
butcher block style as in edge gluing on bare wood.
Those are the 2 sides. The front, divider and back
are particle board which, according to what was said
earlier give a lossy quality which is good. This is
also bare with no surface treatments.
Lastly, the curtain wall idea sounds cool. Maybe
it could be suspended by a piece of wood or sandwiched
between 2 strips and hung freely to turn this way
and that at the diagonal corners.
I'm wondering if the felt would be square like a
curtain or have to cut triangularly looking like a
pennant.
[hope this post goes through-- I made my answer
5 hours ago but the post never showed. :-/
wixy said:
Technically, the one on the Zillaspeak link is the ideal way to go. Most people just go with L/2 as it gets you close enough 99% of the time. Still, if you want to do 'er perfectly, then using the method outlined will give the ideal box.
The felt sounds like a good plan -give it a shot.
Depending on the size of your room and your taste in music and volume levels of course, 2 watts is generally plenty with the Fostex 206/7 drivers, which are rated at something like 97db, and might be abit optimistic. I have a feeling that with horn and room gain, the BIB's can give something in the area of a 10db lift <1500Hz, is what reading I get using my Mark II Tympano-cochleometer. At any rate I have three amps, neither with more than about 3 watts, (6DN7, 13EM7, 45) and they all can rock with the 168, which is less sensitive than that which you speak of, so your build should at least theoretically offer more output.
Having said that, I wish I had 4-10 bottled watts for these things...
Having said that, I wish I had 4-10 bottled watts for these things...
i did some calc's on a BIB w/ Fostex 206e and realized that the center of the driver will be at 52" or 135cm height but my audio/hearing position requires mounting in a height about 35 " or 90 cm. rotating the bib will give me the wanted height (cause z=35") but then i need about 4" or 10cm additional height to create cutouts which will fit the estimated sm. Is it possible to short the line and what problems will occur?
galac
galac