Well, I think I'm going to go ahead with the BiB design in a few weeks...
Thanks to GM's suggestion
http://www.zillaspeak.com/bib-pioneer.asp
Sounds, workable, dosen't it?
Thanks to GM's suggestion
http://www.zillaspeak.com/bib-pioneer.asp
Sounds, workable, dosen't it?
Well, if I can't get reasonable results with 4' lumber, I might as well make BiBs 
With the B20s, that'll require a serious rearrangement of my space.
The saving grace right now is that my wife, for once, heard the new B20s and asked if they could fit into the speakers in "her" living room, which of course they are perfectly suited for. Already have 4ohm Neo3PDR tweets in them on 2.2uF caps. Only thing necessary would be to pop off the narrower negative termination on the woofer line and replace it with another wide one. That would leave me speakerless up here, which means I could be free to build one of the more reasonable BiBs for a Fostex driver of some flavor or maybe a 4" TB bamboo . . .
Kensai
With the B20s, that'll require a serious rearrangement of my space.The saving grace right now is that my wife, for once, heard the new B20s and asked if they could fit into the speakers in "her" living room, which of course they are perfectly suited for. Already have 4ohm Neo3PDR tweets in them on 2.2uF caps. Only thing necessary would be to pop off the narrower negative termination on the woofer line and replace it with another wide one. That would leave me speakerless up here, which means I could be free to build one of the more reasonable BiBs for a Fostex driver of some flavor or maybe a 4" TB bamboo . . .
Kensai
Zilla,
Mainly just talking about using standard sizes of lumber and minimize the amount of cutting I'll have to do. I've got small miter box and back saw and a B&D rotary cutter (dremel) with circle and edge cutters and that's it, so I'm hoping to get a design that will be simple to knock together without needing another investment in tools. Which of course means that I need to keep the price down on materials (4' lumber being significantly cheaper than 6' lumber, which again is significantly cheaper than 8' lumber; I simply don't have the means to transport or cut down full sheets of ply or MDF).
As for the footprint, its not really that I want a small one, just that I don't really have the space for it. They would go next to my desk which is in a corner. Getting the desk out of the corner would be difficult, and even then it would be up against a wall to it would be hard to place a deep pair of BiBs well. The B20s are there now in OB, hinge mounted to the desk itself, so they have 0 footprint and have nearly unlimited placement flexibility.
Right now its looking like the B20 project for me will be to put them in the old sealed Yamaha cabinets in the living room, mated to my B&G Neo3PDRs. The way those are set up, the original Yamaha 8"ers are pretty thunderous (flat to 40Hz, present at 30Hz, though 20Hz is at least another 20dB down), the way they use the entertainment center as sounding board and the floor for reinforcement (not to mention using the entertainment center as a huge virtual baffle to eleminate any baffle step issues), so I'm guessing the B20s will have similar bottom end. The B20, though, are noticeably more articulate and fun sounding. I'm just worried about having them mounted so low as you've mentioned that they aren't great unless pointed right at you. I'm noticing that just with baffle angle in the near field, but that is mainly a loss of air, and I am EQing the top end back into them, so that's kind of an unnatural situation. In the livingroom, too, the minimum listening distance is over a dozen feet, so there should be alot more space for wave propigation and the influence of reflections on what's heard.
As for the office, well, I'm just going to have to pick something alot smaller to work with, say a 4.5" or smaller Fostex. I've also got a hankering to make HiVi B3S BiBs. Scott had provided dims for some (tiny little things), but not a sim, so I have no idea what kind of bass they might have (I'd love it if they could get to 60Hz, but I'm guessing its closer to the 70-80 range). I could actually make them 4 pieces per side in little mini lines (with 4x the mouth opening) and still easily get them into 4' cabinets while raising the zdriver point closer to ear height (which I find is more like 42" in real life). Just wish I knew if I could actually get any real bass out of those little things as this concept still needs $80 worth of drivers to be competitive with a Fostex based one. Regardless, I need to come up with something before I sacrifice my B20s to the livingroom goddess.
Kensai
Mainly just talking about using standard sizes of lumber and minimize the amount of cutting I'll have to do. I've got small miter box and back saw and a B&D rotary cutter (dremel) with circle and edge cutters and that's it, so I'm hoping to get a design that will be simple to knock together without needing another investment in tools. Which of course means that I need to keep the price down on materials (4' lumber being significantly cheaper than 6' lumber, which again is significantly cheaper than 8' lumber; I simply don't have the means to transport or cut down full sheets of ply or MDF).
As for the footprint, its not really that I want a small one, just that I don't really have the space for it. They would go next to my desk which is in a corner. Getting the desk out of the corner would be difficult, and even then it would be up against a wall to it would be hard to place a deep pair of BiBs well. The B20s are there now in OB, hinge mounted to the desk itself, so they have 0 footprint and have nearly unlimited placement flexibility.
Right now its looking like the B20 project for me will be to put them in the old sealed Yamaha cabinets in the living room, mated to my B&G Neo3PDRs. The way those are set up, the original Yamaha 8"ers are pretty thunderous (flat to 40Hz, present at 30Hz, though 20Hz is at least another 20dB down), the way they use the entertainment center as sounding board and the floor for reinforcement (not to mention using the entertainment center as a huge virtual baffle to eleminate any baffle step issues), so I'm guessing the B20s will have similar bottom end. The B20, though, are noticeably more articulate and fun sounding. I'm just worried about having them mounted so low as you've mentioned that they aren't great unless pointed right at you. I'm noticing that just with baffle angle in the near field, but that is mainly a loss of air, and I am EQing the top end back into them, so that's kind of an unnatural situation. In the livingroom, too, the minimum listening distance is over a dozen feet, so there should be alot more space for wave propigation and the influence of reflections on what's heard.
As for the office, well, I'm just going to have to pick something alot smaller to work with, say a 4.5" or smaller Fostex. I've also got a hankering to make HiVi B3S BiBs. Scott had provided dims for some (tiny little things), but not a sim, so I have no idea what kind of bass they might have (I'd love it if they could get to 60Hz, but I'm guessing its closer to the 70-80 range). I could actually make them 4 pieces per side in little mini lines (with 4x the mouth opening) and still easily get them into 4' cabinets while raising the zdriver point closer to ear height (which I find is more like 42" in real life). Just wish I knew if I could actually get any real bass out of those little things as this concept still needs $80 worth of drivers to be competitive with a Fostex based one. Regardless, I need to come up with something before I sacrifice my B20s to the livingroom goddess.
Kensai
Godzilla's slot-loaded B20 - well, unfortunately I need to leave the field of my living room to lie fallow for a bit before I try to farm another crop of speakers into it - thus sayeth the wife. But I've got a friend who is liking my new needles and I have him convinced that he wants a b20 based speaker. We'll see if he's actually ready to step up to the plate... I'll be pulling for GZ's design here posted. I'll write back if we build it!
Kensai -> If I get a say in what you build to go next to your desk after the B20's have moved on, then I vote for the 4" TB Bamboo. That's if you want any input... I'm curious about the driver.
I'll be pulling for GZ's design here posted. I'll write back if we build it!Kensai -> If I get a say in what you build to go next to your desk after the B20's have moved on, then I vote for the 4" TB Bamboo.
That's if you want any input... I'm curious about the driver.
Adam,
Yeah, I'm curious too, and Zilla's had a few interesting things to say about his. Price is a bit higher than the most expensive Fostex I'm looking at, so I'm going to need to solicit input on that, probably over on the big BiB thread since I can make one that will more easily shoehorn into my space with these smaller drivers. I'm going to be looking for something that, when placed in a BiB will give me similar if not better enjoyment as the B20, without need to EQ in the bottom or top (though I'm sure I will push the bottom a little anyway ;-p). I guess I would be looking between the 4" TB Bamboo and Fostex FE126/127 and FF125K for that project.
I'm just not entirely chomping at the bit to move the B20s out of the office. Even with the need for serious EQ, they are the most fun speakers I've had experience with, and I have a hard time throwing money after stuff that I'm not 100% convinced will sound better, to me, than what I have in hand.
Maybe just some 4' tall sealed cabs for the time being? Could use them as removeable surrounds for the living room at some point in the future ;-p
Kensai
Yeah, I'm curious too, and Zilla's had a few interesting things to say about his. Price is a bit higher than the most expensive Fostex I'm looking at, so I'm going to need to solicit input on that, probably over on the big BiB thread since I can make one that will more easily shoehorn into my space with these smaller drivers. I'm going to be looking for something that, when placed in a BiB will give me similar if not better enjoyment as the B20, without need to EQ in the bottom or top (though I'm sure I will push the bottom a little anyway ;-p). I guess I would be looking between the 4" TB Bamboo and Fostex FE126/127 and FF125K for that project.
I'm just not entirely chomping at the bit to move the B20s out of the office. Even with the need for serious EQ, they are the most fun speakers I've had experience with, and I have a hard time throwing money after stuff that I'm not 100% convinced will sound better, to me, than what I have in hand.
Maybe just some 4' tall sealed cabs for the time being? Could use them as removeable surrounds for the living room at some point in the future ;-p
Kensai
Kensai - I'm not sure its a good idea to put the Hi-Vi B3S in a BIB. In one of John "Zaph" Krutke projects he uses that driver in a small sealed box and recommends the use of a subwoofer as it has "serious harmonic distortion below 100hz" (http://www.zaphaudio.com/audio-speaker18.html).
Don't get me wrong though -- I think this is a great driver and I have the round flange version, the B3N, on order from Madisound. I'll be trying it out in an OB and a Linkwitz Pluto copy.
-----
Back to the topic.
I know the B20's T-S parameters don't suggest an OB but I am increasingly attracted to this approach.
I tried modeling the B20 in an OB without success. The bass rolled off below 100 Hz too quickly to be effective. Even adding series resistance to raise the Qts didn't seem to help much. Has anyone tried the B20 in an OB?
Don't get me wrong though -- I think this is a great driver and I have the round flange version, the B3N, on order from Madisound. I'll be trying it out in an OB and a Linkwitz Pluto copy.
-----
Back to the topic.
I know the B20's T-S parameters don't suggest an OB but I am increasingly attracted to this approach.
I tried modeling the B20 in an OB without success. The bass rolled off below 100 Hz too quickly to be effective. Even adding series resistance to raise the Qts didn't seem to help much. Has anyone tried the B20 in an OB?
GM - what did you do to mass load and damp Pioneer B20FU20-54F? Its QTS seems to low to easily use (ie. passively) in an OB.
I was thinking of adding the Goldwood GW-215/8 for this application. Its a 15" woofer at the same price but with a very high QTS of 1.95 (http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=290-345).
I was thinking of adding the Goldwood GW-215/8 for this application. Its a 15" woofer at the same price but with a very high QTS of 1.95 (http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=290-345).
Greets!
Well, I didn't say it was the best choice! It's just what I had laying around at the time when a bunch of folks on the old fullrangers forum were experimenting with the B20, so cobbled up a prototype to see what we were up against. Anyway, don't believe those low Qt specs. I added quite a bit of Poster Tack to the DC and surrounding area to temporarily mass load it, lowering Fs and raising Qt while damping down much of its mids/HF BW. I further damped it by adding a 3/4" thick polyfil sheet grill to finish off its acoustic XO.
It wasn't going to win any awards or play at Head Banger's Ball levels, but it worked pretty good overall once I put a polyfil $0.98 tweak on the B20's whizzer and added a piezo super tweeter nestled in the lee of the tandem drivers to semi-mimic a huge oval point source and add a bit of top end 'air'.
GM
Well, I didn't say it was the best choice!
It's just what I had laying around at the time when a bunch of folks on the old fullrangers forum were experimenting with the B20, so cobbled up a prototype to see what we were up against. Anyway, don't believe those low Qt specs. I added quite a bit of Poster Tack to the DC and surrounding area to temporarily mass load it, lowering Fs and raising Qt while damping down much of its mids/HF BW. I further damped it by adding a 3/4" thick polyfil sheet grill to finish off its acoustic XO. It wasn't going to win any awards or play at Head Banger's Ball levels, but it worked pretty good overall once I put a polyfil $0.98 tweak on the B20's whizzer and added a piezo super tweeter nestled in the lee of the tandem drivers to semi-mimic a huge oval point source and add a bit of top end 'air'.
GM
Oh, since it takes 4x the area or excursion to drop an octave, you made the right choice stepping up to a 15". As for such a high Qt, while it allows a relatively narrow baffle, I'm not sure going > ~1.4 Qt is a good plan SQ wise with the high XO point required by the B20.
As always though, YMMV.
As always though, YMMV.
holdent,
Yeah, I'm using them in 16"x20" OBs hinge mounted to my desk. They require EQ to get their bass back, but even on these small baffles, I'm not running over 40% volume on my 20w/c JVC amp to get them loud enough to listen to them in the next room. With proper EQ these are good fullrange units, especially for nearfield us or with careful placement/toe-in, though the sweet spot is pretty small if you're EQing the top end back into them (really bad off axis response in the last octave).
Without EQ, I believe they start rolling off noticeably around 120Hz in my small baffles. A larger baffle might get you to 100Hz or a bit lower, but not much. A nice high Qts 15" like you mention would be really nice for the bottom, provided you have the space for such monsters. On top, I prefer a nice planar like a B&G Neo3PDR (with the back cup removed, of course), but at 10-20 times the price, that's not really a worthy option, especially if you mod and cross a cheap piezo as Zilla describes.
Post pics if you do this
Kensai
Yeah, I'm using them in 16"x20" OBs hinge mounted to my desk. They require EQ to get their bass back, but even on these small baffles, I'm not running over 40% volume on my 20w/c JVC amp to get them loud enough to listen to them in the next room. With proper EQ these are good fullrange units, especially for nearfield us or with careful placement/toe-in, though the sweet spot is pretty small if you're EQing the top end back into them (really bad off axis response in the last octave).
Without EQ, I believe they start rolling off noticeably around 120Hz in my small baffles. A larger baffle might get you to 100Hz or a bit lower, but not much. A nice high Qts 15" like you mention would be really nice for the bottom, provided you have the space for such monsters. On top, I prefer a nice planar like a B&G Neo3PDR (with the back cup removed, of course), but at 10-20 times the price, that's not really a worthy option, especially if you mod and cross a cheap piezo as Zilla describes.
Post pics if you do this
Kensai
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