ratio minimizes the discontinuity in the flare, but I will take your word for it and consider it a good homework problem. Godzilla said:
You haven't checked out the SI mod thread in the Class D forum?
The SI T-amp has a small value input coupling cap that causes the bass to roll off exactly as you have experienced. It's a cheap, battery powered amp, they never intended it for use with speakers that can actually make bass!
If you don't mind doing a little soldering (and can handle surface mount devices), you can replace the coupling caps and get the bass back. Instructions on Panomaniac's site - see the Input Mods link.
Greets!
Can't explain the math since I don't know it, but I can draw to scale and measure 'close enough' and at this ratio the flare remains constant, so while it doesn't expand at quite the same rate as before and after the bend, it doesn't squeeze down or balloon out either, ergo essentially a ~insignificant constant pressure in both directions for a short distance.
GM
Can't explain the math since I don't know it, but I can draw to scale and measure 'close enough' and at this ratio the flare remains constant, so while it doesn't expand at quite the same rate as before and after the bend, it doesn't squeeze down or balloon out either, ergo essentially a ~insignificant constant pressure in both directions for a short distance.
GM
stroop said:
are you going with an upward or downward venting enclosure? i'm having trouble getting my pair to couple properly with the room (3m ceilings). still sound pretty nice though. proper stuffing makes a big difference as well to counter midranges leaking and a fatiguing sound. still haven't gotten mine exactly right as i think i've killed too much of the dynamics with the stuffing directly behind the driver.
on some songs though, when they do sound right, they sound really, really good!
Thanks for the Neofone responses Guys.
I will stick with these dims:
Line length: 128 in
Zdriver: 25.75 in
Sm: 55 sq in
I got the neofones from Brian to put onto a large ported box, they worked well with a fantastic midrange, but the bass was just like base from any other ported box ;-(
I've been running Ron Clark's Austin FE166 horns for about 9 months and have got used to bass that sounds like the real, room filling thing.
Hope the Neofones in BIB will be as good.
Will report back in a few weeks to let you all know.
Verk.
I will stick with these dims:
Line length: 128 in
Zdriver: 25.75 in
Sm: 55 sq in
I got the neofones from Brian to put onto a large ported box, they worked well with a fantastic midrange, but the bass was just like base from any other ported box ;-(
I've been running Ron Clark's Austin FE166 horns for about 9 months and have got used to bass that sounds like the real, room filling thing.
Hope the Neofones in BIB will be as good.
Will report back in a few weeks to let you all know.
Verk.
Hi Giantstairs,
I'm going to make them basically a straightened out BIB with the driver at around .434 the length....They'll 250cm tall and venting out the top! Main reason is so that I can get them to interact with my high ceilings. about 3.1m.
Good point abput the stuffing...I'm not at all sure where to start there. I guess I'll just build 'em and see. I'll add felt to the magnet etc and also maybe a little wool behind the driver, I was thinking of putting cork on the front wall and felt along the back.
I'll be needing all the help I can get at that point!
Cheers Stroop
I'm going to make them basically a straightened out BIB with the driver at around .434 the length....They'll 250cm tall and venting out the top! Main reason is so that I can get them to interact with my high ceilings. about 3.1m.
Good point abput the stuffing...I'm not at all sure where to start there. I guess I'll just build 'em and see. I'll add felt to the magnet etc and also maybe a little wool behind the driver, I was thinking of putting cork on the front wall and felt along the back.
I'll be needing all the help I can get at that point!
Cheers Stroop
spooky
I'm testing my BIB (singular) with an organ recital.
Heard a couple spooky low notes which, as a
non audiophile who may used to such things, was
unusual.
My Yamaha SS amp is hooked up to these. I
may pass on the Sonic Impact t-amp until I know
more.
If changing components on the thing make it sound
like a Radio Shack SA 155, I'll pass.
For now, the BIB has gotten rid of the drainpipe
sound and expresses vocal and music-- how to
say-- discreetly without any overtones from the
terminus.
I'm curious about the Stereophile test disk now.
Maybe it is in the PE catalogue.
I'm testing my BIB (singular) with an organ recital.
Heard a couple spooky low notes which, as a
non audiophile who may used to such things, was
unusual.
My Yamaha SS amp is hooked up to these. I
may pass on the Sonic Impact t-amp until I know
more.
If changing components on the thing make it sound
like a Radio Shack SA 155, I'll pass.
For now, the BIB has gotten rid of the drainpipe
sound and expresses vocal and music-- how to
say-- discreetly without any overtones from the
terminus.
I'm curious about the Stereophile test disk now.
Maybe it is in the PE catalogue.
The Stereophile CD has bass test tones. You play the tones to see how low your speakers can go. Also, by playing thru each tone, you can hear how flat your speakers are in the bass. In other words, when you play the 60hz, 50hz, 40hz etc… you can hear if the notes play at the same volume level or if some play louder or softer. The 168s BIB is flat to 40hz according to my ears. Then the level begins to drop at 30, 25, 20hz… but 20hz is audible when I turn the volume up. The stock $30 SI amp produces no sound that I was able to hear after 40hz… and it was very low in volume.
I’m sure PE has something similar to the Stereophile CD.
I’m sure PE has something similar to the Stereophile CD.
Hi everyone,
Giantstairs and stroop have brought up the stuffing thing again,
and now with one cabinet glued up, and the other with just one side
to go on, this is my next problem.
What is the best stuffing option for a BIB?
Polyfill, felt carpet underlay, cork, what about moray james' perlite,
would there be any potential problem with putting a layer of perlite
on the bottom?
I need some help to at least get into the ballpark. I've left the bases
unglued as Scott earlier suggested to make adjustments, but the
cabinets are 3.5cm thick and don't have handles, so lifting them up
and placing them over a pile of stuffing placed on the base is not easy.
Godzilla said he added stuffing from the top, and pushed it down with
a broom handle. How did he get it around the bend.
I might be making this harder than it really is.
Any help greatly appreciated.
Thanks, John.
Giantstairs and stroop have brought up the stuffing thing again,
and now with one cabinet glued up, and the other with just one side
to go on, this is my next problem.
What is the best stuffing option for a BIB?
Polyfill, felt carpet underlay, cork, what about moray james' perlite,
would there be any potential problem with putting a layer of perlite
on the bottom?
I need some help to at least get into the ballpark. I've left the bases
unglued as Scott earlier suggested to make adjustments, but the
cabinets are 3.5cm thick and don't have handles, so lifting them up
and placing them over a pile of stuffing placed on the base is not easy.
Godzilla said he added stuffing from the top, and pushed it down with
a broom handle. How did he get it around the bend.
I might be making this harder than it really is.
Any help greatly appreciated.
Thanks, John.
Regarding felt...
just thought that I would mention that if you are going to use felt say behind the driver or on the flat of the bend etc. make the effort to use real wool felt. While synthetic felts will work they are nowhere near as uniform or broadband in absorption as is real wool felt. If you are at a loss as to where to buy wool felt you can in a pinch usually buy 1/16 -1/8 inch wool felt sheets at handy craft stores. This can be layered up to what ever thickness you desire and fixed in place in a number of ways. Do not use spray adhesive to laminate the felt. Spots of adhesive are ok but not full area coverage as this will make it very reflective. As with any damping material the least amount that damps out your specific issue is the correct amount to use and real wool will go a long way toward achieving that goal. Remember too that application can also make a difference. Thin sections of hanging felt can sometimes be far more effective than a thicker layer stuck onto a flat surface. Experiment and use as little as is necessary. You might consider trying a thin suspended layer at the bottom of your bib rather than a thick layer(s) on the bottom sbend where sound waves bouncing multiple times through a layer like this combined with the physical motion of the felt (friction in the fibers)all eat up much more energy than would a thicker layer stuck to the bottom panel of the cabinet. Have fun and enjoy your new speakers. Hope that you have a very happy Christmas. Best regards Moray James.
just thought that I would mention that if you are going to use felt say behind the driver or on the flat of the bend etc. make the effort to use real wool felt. While synthetic felts will work they are nowhere near as uniform or broadband in absorption as is real wool felt. If you are at a loss as to where to buy wool felt you can in a pinch usually buy 1/16 -1/8 inch wool felt sheets at handy craft stores. This can be layered up to what ever thickness you desire and fixed in place in a number of ways. Do not use spray adhesive to laminate the felt. Spots of adhesive are ok but not full area coverage as this will make it very reflective. As with any damping material the least amount that damps out your specific issue is the correct amount to use and real wool will go a long way toward achieving that goal. Remember too that application can also make a difference. Thin sections of hanging felt can sometimes be far more effective than a thicker layer stuck onto a flat surface. Experiment and use as little as is necessary. You might consider trying a thin suspended layer at the bottom of your bib rather than a thick layer(s) on the bottom sbend where sound waves bouncing multiple times through a layer like this combined with the physical motion of the felt (friction in the fibers)all eat up much more energy than would a thicker layer stuck to the bottom panel of the cabinet. Have fun and enjoy your new speakers. Hope that you have a very happy Christmas. Best regards Moray James.
You can download test tones here for free:
http://www.realtraps.com/test-cd.htm
They aren't nearly as extensive as the Stereophile CD's, but they will let you know how low you are getting. They will also show you how your room is working (or not working.)
pj
http://www.realtraps.com/test-cd.htm
They aren't nearly as extensive as the Stereophile CD's, but they will let you know how low you are getting. They will also show you how your room is working (or not working.)
pj
gychang said:
I was playing with these on the FE127e's with both
BIB and MLTL.
The firsr couple are so low only many whales can hear
them. At 40 hz I becan to hear stuff.
But I am almost 60. Maybe kids can hear those first
couple samples.
There was some speaker 'frying' at the cone area
and I was hearing the tones at the terminus of the
BIB. The tone was more generalized at the MLTL
and louder and more pronounced.
I can't do that very long. I think it messes with my head.
;-)
Problem I had was getting a copy onto cd. Nero didn't
like the stuff in the folder though Winamp was playing
the tones through the AC'3 sound on the computer alright.
Godzilla said:
Zilla, I keep trying to tell you:
See this measurement page on my T-AMP site.
The image below is the stock and modifiied S.I. amp
Subjectively it is even worse because of power supply problems.
A really Good T-Amp should rock on your BIBs.
