loninappleton said:
OT -don't forget the sequal, Ashes to Ashes, set in the early 1980s. No Sam Tyler, but Gene is still there, with a selection of the most gloriously un-PC remarks, such as (if you will forgive the quote): "Today, my friend, your diary entry will read: took a prozzie hostage and was shot by three armed b@$#@%ds." Yep, the Gene Genie is back. Series Two is currently being filmed.
Scottmoose said:
OT -don't forget the sequal, Ashes to Ashes, set in the early 1980s. No Sam Tyler, but Gene is still there, with a selection of the most gloriously un-PC remarks, such as (if you will forgive the quote): "Today, my friend, your diary entry will read: took a prozzie hostage and was shot by three armed b@$#@%ds." Yep, the Gene Genie is back. Series Two is currently being filmed.
We can take this into mail if you like. I'm a big fan of both series.
Life On Mars was touted to go into an American version. That's the only way I found out about it: www.sci-fi.com
You have to really get your mind into the show to get all the
subtleties. What I was stuck on while watching Ashes To Ashes
(again on torrents) was the bar setting. It's way unlike Hunt to hang out in an Italian restaurant. That's part of _her_ fantasy.
You can mail me if you want to talk about this. Since mail is sort of flakey when digested by DIY audio it's here:
lon@athenet.net
When a US dvd release is out, I want my library to get it. I'm very much behind this show.
Now back to BIB's.
I have still to set up my slightly unmatched BIB pair. There may indeed be a weakness in my audio source which gives the BIB at lower volume on broadcast but picks up on streams. the newly build one had to go back on the operating table for a few refinements. I have a removable bottom for restringing wire and whatnot so how does a tightly secured bottom plate on the build effect anything?
I am putzing around making a test box for a new MLTL for a Tangband 5.5 in.
Inverted BiB Bipole - Spaced Drivers
Hi folks, GM said that in post #2997 (page 120) in response to dmason's proposal to build a bipolar inverted BiB with the drivers mounted back-to-back on the wide side.
If one were to mount the drivers in two different places along the line (rather than back-to-back), is there a rule of thumb as to what the two optimal places would be? Or does one simply try to place both drivers so that the line "sees" an average of .434 * line length? Or is there any other rule of thumb to apply here which gets an advantage in terms of the mid-bass dip, ripple or anything else?
(I realize that Vb doubles, and that width / depth should be in the ratio of 1:1.414 or so while line length remains the same. Secondary driver would be rolled off allowing some placement options.)
The drivers are FE166E's, if that has any bearing.
(I realize these boxes would be impractical large for home, but I work at a college and these would fit in an existing space that already has very bulky speakers.)
Thanks in advance for any insight you can provide!
Edit: If you want to view post #2997: http://www.diyaudio.com/forums/showthread.php?postid=1193972#post1193972
GM said:Wide baffle bipolar floor loaded folded pipe horn....... my kind of efficient, simple to build DIY speaker!
Hi folks, GM said that in post #2997 (page 120) in response to dmason's proposal to build a bipolar inverted BiB with the drivers mounted back-to-back on the wide side.
If one were to mount the drivers in two different places along the line (rather than back-to-back), is there a rule of thumb as to what the two optimal places would be? Or does one simply try to place both drivers so that the line "sees" an average of .434 * line length? Or is there any other rule of thumb to apply here which gets an advantage in terms of the mid-bass dip, ripple or anything else?
(I realize that Vb doubles, and that width / depth should be in the ratio of 1:1.414 or so while line length remains the same. Secondary driver would be rolled off allowing some placement options.)
The drivers are FE166E's, if that has any bearing.
(I realize these boxes would be impractical large for home, but I work at a college and these would fit in an existing space that already has very bulky speakers.)
Thanks in advance for any insight you can provide!
Edit: If you want to view post #2997: http://www.diyaudio.com/forums/showthread.php?postid=1193972#post1193972
Greets!
Depends. If both are used full BW, then there's none other than choosing the least problematic offset AFAIK, but if you're rolling one off, then you can adjust it to negate the third harmonic dip somewhat. This is a waste of two FE166Es IMO since you can use some cheap woofers on the back to do this.
How did you arrive at the 0.434*L?
GM
Depends. If both are used full BW, then there's none other than choosing the least problematic offset AFAIK, but if you're rolling one off, then you can adjust it to negate the third harmonic dip somewhat. This is a waste of two FE166Es IMO since you can use some cheap woofers on the back to do this.
How did you arrive at the 0.434*L?
GM
Howdy GM, it's mentioned in a few other posts in this thread -- .217 for regular BiB, .434 for inverted. But I see now in post #2161 that you say:
https://www.diyaudio.com/community/threads/bbbib-bigger-badder-bib-speaker.88104/post-1102698
I wish I had seen that -- newb error to be overly literal. I will definitely consult MJK's Classic TL alignment tables. Thank you -- I appreciate it!
https://www.diyaudio.com/community/threads/bbbib-bigger-badder-bib-speaker.88104/post-1102698
I wish I had seen that -- newb error to be overly literal. I will definitely consult MJK's Classic TL alignment tables. Thank you -- I appreciate it!
Last edited by a moderator:
Greets!
Hmm, I'd forgotten about that post. My BIB calculator has it at 0.416 which I thought was MJK's official best compromise driver position. Regardless, I was just making the point that there's no fixed 'best' driver position even if they're all the same length.
FYI, his Classic TL alignment tables' driver positions for different expansions won't work since they don't allow for the BIB's zero throat area.
GM
Hmm, I'd forgotten about that post. My BIB calculator has it at 0.416 which I thought was MJK's official best compromise driver position. Regardless, I was just making the point that there's no fixed 'best' driver position even if they're all the same length.
FYI, his Classic TL alignment tables' driver positions for different expansions won't work since they don't allow for the BIB's zero throat area.
GM
Hi all,
Heh heh, quick WAF story...
My BIBs are very big ( 290 x 420 x 1800mm) so are my old NHT1259 subs (600mm cubes)
The Mrs is happy with the BIBs in the lounge (happy ? Well barely tolerant would be a better description, but she knows how much I like them)
We were looking at the lounge, it's quite small and the BIBs/subs are quite big, she asked if I could do something about it.
Oh yes... I can... I popped back to the part of the thread about wings on the BIBs. I'm going to reshape my subs into side firing 200 x 1800 x 420mm 'wings' and stick 'em to the BIBs
What a great idea she says.
Ooh yeah. I'm a nut, but she's really crazy.
Sedge.
Heh heh, quick WAF story...
My BIBs are very big ( 290 x 420 x 1800mm) so are my old NHT1259 subs (600mm cubes)
The Mrs is happy with the BIBs in the lounge (happy ? Well barely tolerant would be a better description, but she knows how much I like them)
We were looking at the lounge, it's quite small and the BIBs/subs are quite big, she asked if I could do something about it.
Oh yes... I can... I popped back to the part of the thread about wings on the BIBs. I'm going to reshape my subs into side firing 200 x 1800 x 420mm 'wings' and stick 'em to the BIBs
What a great idea she says.
Ooh yeah. I'm a nut, but she's really crazy.
Sedge.
Hi,
No, the BIBs are 1.7m in from the corners, I'll fire the subs outwards.
Yes, I'm going to attach the subs directly to the existing cabs, they will be well braced. Separate cabs ? I couldn't bring myself to tiptoe a very thin, very tall box of impending doom in the lounge with a five year old running round.
I've had two subs for years, run active/stereo, never sounded right with one. Small room, yes, I just don't turn them up that loud (mostly)
I'll post some photos when I get the things together.
<insert evil cackle here>
Sedge.
No, the BIBs are 1.7m in from the corners, I'll fire the subs outwards.
Yes, I'm going to attach the subs directly to the existing cabs, they will be well braced. Separate cabs ? I couldn't bring myself to tiptoe a very thin, very tall box of impending doom in the lounge with a five year old running round.
I've had two subs for years, run active/stereo, never sounded right with one. Small room, yes, I just don't turn them up that loud (mostly)
I'll post some photos when I get the things together.
<insert evil cackle here>
Sedge.
some tweakage is needed
I have a BIB abd it's step brother with the double front baffle.
Interior treatment is similar but not identical.
The BIB original is giving a better midrange whereas the
double front baffle (one cutout 4 in, the interior cutout 5 in)
gives the mids coming out the front a muted effect.
So suprabaffle on these.
I do not think minor surgery such as chamfering the inside baffle
would change this.
The original 'good sounding' BIB currently has the thin wire
tweak on it but here again I think this is minor.
Both use FE127e. Both are about the same same size and the
newer sibling is closer to the calculator measures.
What concerns me is what's coming out the front and less so
what is coming out the top.
Anyway, the BIB thread lives!
I have a BIB abd it's step brother with the double front baffle.
Interior treatment is similar but not identical.
The BIB original is giving a better midrange whereas the
double front baffle (one cutout 4 in, the interior cutout 5 in)
gives the mids coming out the front a muted effect.
So suprabaffle on these.
I do not think minor surgery such as chamfering the inside baffle
would change this.
The original 'good sounding' BIB currently has the thin wire
tweak on it but here again I think this is minor.
Both use FE127e. Both are about the same same size and the
newer sibling is closer to the calculator measures.
What concerns me is what's coming out the front and less so
what is coming out the top.
Anyway, the BIB thread lives!
>>> Tomorrow some friends and I are making 10 PAIRS of BOFU BIBs for the participants. We call is Speakermaking Summer Camp. We hope to make them all in a day..
>>> Many participants are younger, so I feel we a re doing a public service getting some great sounding speakers into the world..
I am sorry to have to miss this. Very cool indeed! If you take pictures please forward them to me.
Thanks,
Godzilla
godzilla3@hotmail.com
>>> Many participants are younger, so I feel we a re doing a public service getting some great sounding speakers into the world..
I am sorry to have to miss this. Very cool indeed! If you take pictures please forward them to me.
Thanks,
Godzilla
godzilla3@hotmail.com
"The BIB original is giving a better midrange whereas the
double front baffle (one cutout 4 in, the interior cutout 5 in)
gives the mids coming out the front a muted effect.
...........................Both use FE127e."
Have you tried switching drivers from one cab to the other ?
Also, don't discount small changes such as wire , sometimes it makes a BIG difference.
..........................Blake
double front baffle (one cutout 4 in, the interior cutout 5 in)
gives the mids coming out the front a muted effect.
...........................Both use FE127e."
Have you tried switching drivers from one cab to the other ?
Also, don't discount small changes such as wire , sometimes it makes a BIG difference.
..........................Blake
I hear your suggestions but what I don't understand about the
stuffing materials is how that would diminish the mid tone coming out the front.
For instance: clarinette solo is forward on the one and lost in the
tympany on the other-- or something similar.
The Lost In Translation BIB with the double baffle front has thin
foam behind the driver, fiberfill in the peak and egg crate foam on the bottom.
The Original has fiberfill in the peak, billiard felt behind the driver and
layered fiberfill (very loose) about a 1/2 inch on the bottom.
The cabinet material differs on the sides: butrcherblock glue up pune (prefabe shelving) on the Original, less than void free plywood
on the troublesome one.
To be honest, I tore down one non-BIB build and reused the plywood just so I could see what a couple of BIBs sounded like together.
Considering my usual asymmetric listening style, 2 bibs at close range may just not be a good fit.
Next round of building is an MLTL. The plywood BIB I may set up as part of a different rig in a testing/build room.
stuffing materials is how that would diminish the mid tone coming out the front.
For instance: clarinette solo is forward on the one and lost in the
tympany on the other-- or something similar.
The Lost In Translation BIB with the double baffle front has thin
foam behind the driver, fiberfill in the peak and egg crate foam on the bottom.
The Original has fiberfill in the peak, billiard felt behind the driver and
layered fiberfill (very loose) about a 1/2 inch on the bottom.
The cabinet material differs on the sides: butrcherblock glue up pune (prefabe shelving) on the Original, less than void free plywood
on the troublesome one.
To be honest, I tore down one non-BIB build and reused the plywood just so I could see what a couple of BIBs sounded like together.
Considering my usual asymmetric listening style, 2 bibs at close range may just not be a good fit.
Next round of building is an MLTL. The plywood BIB I may set up as part of a different rig in a testing/build room.
BiB Spreadsheet / Calculator Gotcha
I love the BiB spreadsheet. However, there is one gotcha that I noticed tonight in assembling my FE166E BiB's.
In attempting to get the a-b-c lined up correctly, I ran into trouble -- the divider was too long. In OpenOffice, I checked the formula calculating the slant (divider's) length. My driver happens to be in column F, and the slant length is calculated in cell F41:
=(IF(F21=0;"";MROUND(SQRT(SUMSQ(F30-(F13))+(F13));0.25)))
So the formula states:
If F21 (material thickness) is zero, return an empty string (nothing) to avoid dividing by zero.
But otherwise, calculate the length of the divider according to the Pythagorean theorum (hypotenuse = sum of the squares of the other sides in a right triangle).
To do that:
1. Take height (F30) minus the a-b-c value as one of the sides. Let's call this "a".
2. Take a-b-c- value (F13) as the base, and let's call this "b".
3. The slant's length (call it "c") is equal to the square root of (a^2 + b^2).
4. Round the result to the quarter inch.
The slight issue I noticed is that item #1 fails to account for the .75" of the base. The base is mounted "inside" the other four boards. So really, .75 needs to be subtracted from external height.
If not, then when you are gluing up, you'll notice there's no way to get your a-b-c to come out right. However, the fix is simple: just nudge the divider up until you get your a-b-c (north of the mouth), then trim off that excess.
So I'd recommend changing the above formula to:
=(IF(F21=0;"";MROUND(SQRT(SUMSQ(F30-F21-F13)+(F13));0.25)))
Empirically, when I nudged the divider "higher" than the mouth, until a-b-c- worked out, I got 61" and that's what the revised formula yields as well.
Anyway, thank you to all who worked on the BiB calculator -- it's terrific!
I love the BiB spreadsheet. However, there is one gotcha that I noticed tonight in assembling my FE166E BiB's.
In attempting to get the a-b-c lined up correctly, I ran into trouble -- the divider was too long. In OpenOffice, I checked the formula calculating the slant (divider's) length. My driver happens to be in column F, and the slant length is calculated in cell F41:
=(IF(F21=0;"";MROUND(SQRT(SUMSQ(F30-(F13))+(F13));0.25)))
So the formula states:
If F21 (material thickness) is zero, return an empty string (nothing) to avoid dividing by zero.
But otherwise, calculate the length of the divider according to the Pythagorean theorum (hypotenuse = sum of the squares of the other sides in a right triangle).
To do that:
1. Take height (F30) minus the a-b-c value as one of the sides. Let's call this "a".
2. Take a-b-c- value (F13) as the base, and let's call this "b".
3. The slant's length (call it "c") is equal to the square root of (a^2 + b^2).
4. Round the result to the quarter inch.
The slight issue I noticed is that item #1 fails to account for the .75" of the base. The base is mounted "inside" the other four boards. So really, .75 needs to be subtracted from external height.
If not, then when you are gluing up, you'll notice there's no way to get your a-b-c to come out right. However, the fix is simple: just nudge the divider up until you get your a-b-c (north of the mouth), then trim off that excess.
So I'd recommend changing the above formula to:
=(IF(F21=0;"";MROUND(SQRT(SUMSQ(F30-F21-F13)+(F13));0.25)))
Empirically, when I nudged the divider "higher" than the mouth, until a-b-c- worked out, I got 61" and that's what the revised formula yields as well.
Anyway, thank you to all who worked on the BiB calculator -- it's terrific!
One last thought:
Technically, the base of the triangle (of which the slant is the hypotenuse) is not the value of a-b-c, but rather, the value of a-b-c minus 1/2 of the slant's thickness (material thickness, F21).
This is because the a-b-c "pinpoint" is located at the center of the divider's bottom (at the mid-point of the divider's thickness). But the slant is the hypotenuse of a triangle with a very slightly smaller base (smaller by one half of the slant's thickness).
So we could say subtracting half the slant's thickness is more accurate:
=(IF(F21=0;"";MROUND(SQRT(SUMSQ(F30-F21-F21/2-F13)+(F13));0.25)))
But it's not, because of rounding. For the FE166E, it becomes 60.5 whereas empirically, 61" is more like it. This is because the formulas are ultimately doing multiple roundings, i.e., using a rounded value to derive another value, which is then rounded.
Anyway, I really do love the BiB calculator -- it's a great time saver and a huge help for those of us who can't measure and cut too well. Thank you again to all those folks who have worked on it, directly or indirectly!
Technically, the base of the triangle (of which the slant is the hypotenuse) is not the value of a-b-c, but rather, the value of a-b-c minus 1/2 of the slant's thickness (material thickness, F21).
This is because the a-b-c "pinpoint" is located at the center of the divider's bottom (at the mid-point of the divider's thickness). But the slant is the hypotenuse of a triangle with a very slightly smaller base (smaller by one half of the slant's thickness).
So we could say subtracting half the slant's thickness is more accurate:
=(IF(F21=0;"";MROUND(SQRT(SUMSQ(F30-F21-F21/2-F13)+(F13));0.25)))
But it's not, because of rounding. For the FE166E, it becomes 60.5 whereas empirically, 61" is more like it. This is because the formulas are ultimately doing multiple roundings, i.e., using a rounded value to derive another value, which is then rounded.
Anyway, I really do love the BiB calculator -- it's a great time saver and a huge help for those of us who can't measure and cut too well. Thank you again to all those folks who have worked on it, directly or indirectly!