Scottmoose said:
Greets!
I was looking for something today and re-found a pair of B20s amidst the dust 'bunnies', so ran the numbers for what works for me driver/ceiling height/baffle width wise, arriving at 88" h x 22.5" w x 15.875" d, driver down 48" (all dims i.d.), and since I prefer wider baffles than most, will mount it on the 'side' if I can get some help building them after the thunder-storms pass through. Might even take the woofer versions I have and add them to the internal baffle for a bit of tapped horn boost just for some serious overkill.
Gotta live up to my moniker, right?
GM
GM said:
arriving at 88" h x 22.5" w x 15.875" d, driver down 48" (all dims i.d.), and since I prefer wider baffles than most, will mount it on the 'side' if I can get some help building them
Gotta live up to my moniker, right?
GM
I will be following this, would appreciate pics as u proceed.
gychang
Go Greg! 
This must be your first build for a little while, right? Plus some tapped horn grunt from an internal driver? I look forward to hearing your impressions. 
Out of interest, which way are you planning to mount the woofer on the internal baffle (tapped horns aren't something I pretend to know anything about -I really should read up on them) -driver front into the 1st or 2nd half of the line?
I'm now trying to imagine what they'd do for a recording of an Advent service at Durham Cathedral I've got: 'Oh Come, Oh Come Emanuel' with that majesterial organ should rock the foundations nicely. Not what I normally listen to, but this is probably the ultimate LF recording in my collection.
Cheers
Scott
This must be your first build for a little while, right? Plus some tapped horn grunt from an internal driver? I look forward to hearing your impressions. Out of interest, which way are you planning to mount the woofer on the internal baffle (tapped horns aren't something I pretend to know anything about -I really should read up on them) -driver front into the 1st or 2nd half of the line?
I'm now trying to imagine what they'd do for a recording of an Advent service at Durham Cathedral I've got: 'Oh Come, Oh Come Emanuel' with that majesterial organ should rock the foundations nicely. Not what I normally listen to, but this is probably the ultimate LF recording in my collection.
Cheers
Scott
Greets!
Drawing per this format: http://www.zillaspeak.com/bib-howtobuild.asp
'TBD' = 'to be determined'
GM
Drawing per this format: http://www.zillaspeak.com/bib-howtobuild.asp
'TBD' = 'to be determined'
GM
Scottmoose said:Go Greg!
Out of interest, which way are you planning to mount the woofer on the internal baffle..........
I'm now trying to imagine what they'd do for a recording of an Advent service at Durham Cathedral I've got...........
Greets!
Yeah, I haven't built anything since the cobbled together folded ML-Voigt pipes I did to showcase Dave's tweaked 40-1197 drivers several years ago, though last Fall I designed/supervised a neighbor's re-build of some high SPL PA speakers using multiple vintage Jensen guitar drivers and Magnavox horns to counteract the local's too loud Mexican Polka music. Apparently they liked 'Heavy Metal' about as much as we liked theirs, so dialed it back to reasonable levels.
See attached PDF.
Dunno, but if I add the woofers, they must be able to handle this without 'burping' and/or 'letting all their smoke out' to be deemed adequate: http://www.telarc.com/gscripts/title.asp?sku=CD-80136&mscssid=8F8ECFB191R28PBVB
GM
It will LOOK like a GM!!
You could name it the S.U.V. Subharmonic Ultra-Audio Vortex
Greg, ...as I looked at your diagram, the opening riff of "The Immigrant Song" went off in my head. You might have to take it to the land of the ice and snow just to test, to keep the State Government out of your hair...let alone the neighbors... Dan like.
You could name it the S.U.V. Subharmonic Ultra-Audio Vortex
Greg, ...as I looked at your diagram, the opening riff of "The Immigrant Song" went off in my head.
You might have to take it to the land of the ice and snow just to test, to keep the State Government out of your hair...let alone the neighbors... Dan like.
Hello all!
Back from Microsoft Convergence 2007 – parties until past 3am – 8,500 people, mostly computer geeks and a smattering of pretty girls (typically selling to the geeks). It’s a fun mix. I am exited to come back to find some may build a B20 BIB!
gychang,
>>> Looking back on Zilla's work, I'm seeing that the 8ohm, .47uF circuit is for forward firing piezo, but for rear firing he was running it at 20ohm, 1uF.
Basically, I am tuning by ear to come up with the cap and resistor values. The cap and resistor both play a role in shaping the piezos sound. The 8 ohm resistor lowers the overall output of the piezo, that’s why I used it on the front. The piezo sounds louder with the 20 ohm. I wanted to hear it less when facing forward. That’s also the reason for the smaller capacitor facing forward.
Facing backwards, I also used an Lpad. The Lpad allowed me to be lazier figuring out the exact blending point between piezo and B20. Ultimately, with the B20, I prefer the rear firing approach (cap, resistor and Lpad). This way you can dial in the contribution of the piezo as suits your taste.
Kensai
>>> So you liked your piezo a bit hotter than Zilla suggests. Do you think the damar might tamed the hiss/spit you were getting from it early on?
The piezo has a characteristic sound (some like and some don’t). It’s fizzy. Brushed cymbals don’t exactly sound perfectly real but they are clear and detailed and you can tell it’s brushed cymbals. Damar lessens the 'hiss/spit'. It's a full day process tho, applying the damar - waiting for it to dry - putting the piezo back together. Facing forward it's probably worth it... facing backwards it's not.
As for using 4 piezos – I just drew that on my sketch. I was unsure how much contribution the BIB would make (until I finally built a pair). The BIB contribution is generous. One rear firing piezo should work but since a pair of B20 BIBs will likely be in a large room two piezos MAY even be better. Using the Lpad, you can always turn them down. If using only one, you may want more. Four piezos would be overkill I’m sure… but they are so cheap… and I have 20 in a box so…
A B20 BIB will probably sound amazing!
Happy to be back,
Godzilla
Back from Microsoft Convergence 2007 – parties until past 3am – 8,500 people, mostly computer geeks and a smattering of pretty girls (typically selling to the geeks). It’s a fun mix. I am exited to come back to find some may build a B20 BIB!
gychang,
>>> Looking back on Zilla's work, I'm seeing that the 8ohm, .47uF circuit is for forward firing piezo, but for rear firing he was running it at 20ohm, 1uF.
Basically, I am tuning by ear to come up with the cap and resistor values. The cap and resistor both play a role in shaping the piezos sound. The 8 ohm resistor lowers the overall output of the piezo, that’s why I used it on the front. The piezo sounds louder with the 20 ohm. I wanted to hear it less when facing forward. That’s also the reason for the smaller capacitor facing forward.
Facing backwards, I also used an Lpad. The Lpad allowed me to be lazier figuring out the exact blending point between piezo and B20. Ultimately, with the B20, I prefer the rear firing approach (cap, resistor and Lpad). This way you can dial in the contribution of the piezo as suits your taste.
Kensai
>>> So you liked your piezo a bit hotter than Zilla suggests. Do you think the damar might tamed the hiss/spit you were getting from it early on?
The piezo has a characteristic sound (some like and some don’t). It’s fizzy. Brushed cymbals don’t exactly sound perfectly real but they are clear and detailed and you can tell it’s brushed cymbals. Damar lessens the 'hiss/spit'. It's a full day process tho, applying the damar - waiting for it to dry - putting the piezo back together. Facing forward it's probably worth it... facing backwards it's not.
As for using 4 piezos – I just drew that on my sketch. I was unsure how much contribution the BIB would make (until I finally built a pair). The BIB contribution is generous. One rear firing piezo should work but since a pair of B20 BIBs will likely be in a large room two piezos MAY even be better. Using the Lpad, you can always turn them down. If using only one, you may want more. Four piezos would be overkill I’m sure… but they are so cheap… and I have 20 in a box so…
A B20 BIB will probably sound amazing!
Happy to be back,
Godzilla
Zilla,
Glad to see you back in one piece and in good spirits.
If I ever decide supertweet mine, I'll probably try those 5/8" Dayton domes forward firing (possibly in bipole, since Linkwitz has totally gone insane for that on his Orion++). They're speced to 27kHz so at least the extension should be similar to the piezo.
Unfortunately I'm not in this crew of B20 BiB builders (say that 5 times fast). The only space in my house big enough for even the small versions belongs to my wife ;-p I'll have to stick to my little OBs or maybe build one of the 3-4 concepts I have for TL enclosures and see how they sound (the concepts all use 12"x48" particle boards that would cost me about $2.50 each including tax, so that I can probably afford to experiment with). Of course, I'm still watching this thread very closely. I'm dying to see if these things work out like we hope they will.
Kensai
Glad to see you back in one piece and in good spirits.
If I ever decide supertweet mine, I'll probably try those 5/8" Dayton domes forward firing (possibly in bipole, since Linkwitz has totally gone insane for that on his Orion++). They're speced to 27kHz so at least the extension should be similar to the piezo.
Unfortunately I'm not in this crew of B20 BiB builders (say that 5 times fast). The only space in my house big enough for even the small versions belongs to my wife ;-p I'll have to stick to my little OBs or maybe build one of the 3-4 concepts I have for TL enclosures and see how they sound (the concepts all use 12"x48" particle boards that would cost me about $2.50 each including tax, so that I can probably afford to experiment with). Of course, I'm still watching this thread very closely. I'm dying to see if these things work out like we hope they will.
Kensai
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.