I am confident that you WILL rise to the occasion and "step up", GM!
Not too much nowadays.
Did start using this on-line math solver though: Solve linear and quadratic equations with Step-by-Step Math Problem Solver
GM
Its design routine is very flexible WRT driver specs, but like any vented alignment the optimum Qts' for flattest response over the widest BW is ~0.383 - 0.403.
Qts' = Qts + any added series resistance [Rs]: Qts' = Qts + any added series resistance [Rs]: HiFi Loudspeaker Design
Here's the calculator's math to use as a guide to show how the specs affect its design: Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 59 - diyAudio
As you can see, the program automatically tunes to a full octave below Fs [Fs/2] or whatever frequency you input, so for instance if you wanted to tune it to Fs, then you need to input [2x Fs].
Ideally need very stiff [high MOE] no void plywood such as 3/4" [18-19 mm] Baltic Birch, Apple ply, some grades of marine ply [what I've used], though with small, weak motor [high Qts'] drivers, 3/4" MDF is OK, though with low tunings its sheer weight can make it a two person job.
Much thinner no void ply/MDF can be used if very well braced for the former and massive [removable] exterior panels are attached to stiffen/mass load them [After learning the hard way not to use long runs of Industrial rated Velcro, switched to spaced out short tabs].
GM
Qts' = Qts + any added series resistance [Rs]: Qts' = Qts + any added series resistance [Rs]: HiFi Loudspeaker Design
Here's the calculator's math to use as a guide to show how the specs affect its design: Terry Cain's BIB -why does it work and does anyone have those Fostex Craft Handbooks? - Page 59 - diyAudio
As you can see, the program automatically tunes to a full octave below Fs [Fs/2] or whatever frequency you input, so for instance if you wanted to tune it to Fs, then you need to input [2x Fs].
Ideally need very stiff [high MOE] no void plywood such as 3/4" [18-19 mm] Baltic Birch, Apple ply, some grades of marine ply [what I've used], though with small, weak motor [high Qts'] drivers, 3/4" MDF is OK, though with low tunings its sheer weight can make it a two person job.
Much thinner no void ply/MDF can be used if very well braced for the former and massive [removable] exterior panels are attached to stiffen/mass load them [After learning the hard way not to use long runs of Industrial rated Velcro, switched to spaced out short tabs].
GM
Last edited:
Technically? It's a [TL] horn alignment, ergo any EBP can be made to work, so really depends on the intended app, i.e. how low does it need to go to blend with the room's gain curve at the desired in room location, etc., then reverse engineer what it is once you know the optimal driver's [Fs].
GM
GM
So, here’s my BIB story. It’s a bit long - feel free to skip it or whatever, but I thought at least I would share my experience with this thread in the event anyone wants to banter or ask questions about my journey with a BIB build in 2020.
In December of 2019 I discovered the BIB speaker design, this thread, and webpages from EJ Jordan and Zilla. It was at a time where I was questioning my speaker purchases and seeing more and more DIY alternatives. I found a captivating YouTube video about the Voigt Tubes and that put me over the edge. “Can DIY really be that good and compete with off the shelf products?” I was smitten with the idea of a big sound from a small driver that the BIB promised as well as the perceived simplicity and inexpensive aspect of a build. As a handy guy with a basement full of tools who’s done my fair share of woodworking, I knew I was already half-way there. Fast forward to May. I was furloughed due to Covid and found myself with an abundance of time. I decided it was time to stop reading and start building.
The Build
My research for a driver that would qualify for a BIB enclosure led me to the Dynavox LY401F from Parts Express at $20 each. Being frugal became a necessity and I was treating this as an experiment just to get a sense of how the drivers would work and how a BIB speaker would sound. The driver specs checked all the boxes, especially the low qts according to my research and the advice from the Interwebs. Going into this, my expectations were low because I had just watched a video from Paul McGowan and he was really dissing the horn sound. (In contrast, Steve Guttenburg LOVES horns…I was so conflicted. I’d never personally heard a horn speaker before.) Using the ZIlla calculators made the planning easy enough, and I got to work. My BIBs were made with the LY401F drivers, one sheet of ¾ plywood made the enclosures while two additional ¾ ply strips that were needed for the inner diagonal were found in my scrap pile. The cabinets were assembled using PL Premium polyurethane construction adhesive and screws. Overkill perhaps, but it was what I had on my shelf and my wood glue was pretty old, so I decided I would rather be safe than sorry. I also opted for woodgrain contact paper for the appearance that I ordered from Amazon. DO NOT USE THIS STUFF! From a few feet away it looks okay, but the paper broke on the corners even though they were eased considerably with sanding. It’s very weird brittle stuff. It was cheap, but in this case, I went too cheap. It has since bubbled in places even though I meticulously applied it and rolled it with no bubbles. I had filled and sanded the wood boxes beforehand thinking I was going to paint them, so the surface was flawless and fully prepped. The product is just total crap. I plan to peel this off and go with an actual vinyl wrap or real wood veneer. The inner slopes of the middle construction needed to be arched a bit to accommodate the driver depth. During a side-off test fit, the back of the driver was so close that I felt adding an additional ½” behind the driver by bowing the wall would be easy enough to do and a good idea to ensure a problem-free fit. (I saw in the EJ Jordan designs that they actually cut this piece in two to make the fit work for their drivers.)
Tuning
After assembly I gave them a listen completely empty inside with no stuffing or damping, Yuck. Hollow, echoes, resonances, megaphone-like. Using the driver hole for access I packed bats of fill from the top peak down the channel to about 4” below the driver. At that lower end, I hot glued a piece of plastic net that I cut out of an onion bag to ensure the fill didn’t fall down over time. This took the speaker to the other extreme. Muffled, lifeless, and flat. No bueno. I removed the large amount of stuffing and went with about 1/3 as much. (I really packed it in there initially.) Now it was just lightly filled with fluffy clouds. With that, the tone was actually acceptable. Highs were there, bass was there, but some funky midrange stuff remained and had to change if I would listen to these. I found that when I draped a dish towel over the front and allowed it to flow down the slope into each speaker that an improvement was made. To make that fix permanent, I cut two 3/4” x 24” foam strips and glued them down in the throat there from about an inch below the top on back of the slope down the 24”. Yup. Almost there. Finally I dropped a single piece of craft felt that was cut to the size to the bottom of the speaker that just sits there in the bottom. In terms of what I would call listenability for tone and frequency balance, they seemed to be there. I don’t have any technical measuring devices, but to my ear they sounded flat and balanced, with nothing really stuck out.
From Meh... to OMG!
I’ve listened to the speakers for four months. They are positioned in the corners of my 12x16 living room. I was not impressed with what I was hearing at all. I employed a sub to make up for the lack of bass. The BIBs had good ‘presence’ and definitely didn’t sound like small 4” drivers... and heck, they seemed to image fine when the volume was up a bit. I got a ‘bigger’ room-filling sound than I had with my Ascend CBM170’s in the space, but… I missed some sense of separation and “sparkle.” There was like absolutely no heft or definition. Just lots of mud honestly, with a lack of dynamics. The initial period of telling myself “they just need to break in” led into a long phase of tinkering with positioning or the dampening with no discernible change. I became certain this project was just a misstep and waste of time. Even though I tried to keep my expectations low, you go into these things hoping to be surprised and that it actually works out. Well, I was about done and ready to ditch them and go back to my bookshelf speakers. Then, last week I got to pondering and wondering where I went wrong. I questioned that maybe it was the driver and I should have just used the proven Fostex units? Was it my room? I started re-reading BIB info and then it dawned on me. Maybe it isn’t the speakers at all. All along I was using a pair of 200 watt class D monoblocks that up until this point, had worked well with various speakers I own. I guess I totally forgot the point that these BIBs are highly sensitive and very easy to drive with minimal power. Well, the world of my BIB experience changed 180 degrees when I pulled a 1970’s 15 watt Kenwood receiver out of the closet and put that between my Lounge phono preamp and the BIBs. Oh. My. God. The bass! The everything! What the actual heck! Everything became unbelievably good, instantly. So much low end that you would be hard pressed to believe that I don’t have a sub sitting in the room. The mids are so clear and strong… breathtaking - and the highs are… acceptable. There is now separation and low end rumble and punch, all fullness and sparkle that I was missing. These speakers went from disappointing to absolutely freaking amazing just like that. I’m absolutely astounded. I’ve never had an experience where amplification makes this much of a crazy difference. I’m enamored with the sound I'm getting from these in the last few days. Classical rumbles with an openness, soundstage and detail that make me swear the entire orchestra is right here. Country has depth and twang, while rock has the punch and quickness that make me giggle.
I built these for a total of $110 bucks and they now knock my socks off. Now that I know these can sound so good, I have a couple more vintage receivers upstairs that I’m going to experiment with. I also want to start looking at some tube amps. I’m happy to report that this is one satisfied DIYer and want to thank all those that contributed to this thread and the BIB calculator. Hearing is believing!
In December of 2019 I discovered the BIB speaker design, this thread, and webpages from EJ Jordan and Zilla. It was at a time where I was questioning my speaker purchases and seeing more and more DIY alternatives. I found a captivating YouTube video about the Voigt Tubes and that put me over the edge. “Can DIY really be that good and compete with off the shelf products?” I was smitten with the idea of a big sound from a small driver that the BIB promised as well as the perceived simplicity and inexpensive aspect of a build. As a handy guy with a basement full of tools who’s done my fair share of woodworking, I knew I was already half-way there. Fast forward to May. I was furloughed due to Covid and found myself with an abundance of time. I decided it was time to stop reading and start building.
The Build
My research for a driver that would qualify for a BIB enclosure led me to the Dynavox LY401F from Parts Express at $20 each. Being frugal became a necessity and I was treating this as an experiment just to get a sense of how the drivers would work and how a BIB speaker would sound. The driver specs checked all the boxes, especially the low qts according to my research and the advice from the Interwebs. Going into this, my expectations were low because I had just watched a video from Paul McGowan and he was really dissing the horn sound. (In contrast, Steve Guttenburg LOVES horns…I was so conflicted. I’d never personally heard a horn speaker before.) Using the ZIlla calculators made the planning easy enough, and I got to work. My BIBs were made with the LY401F drivers, one sheet of ¾ plywood made the enclosures while two additional ¾ ply strips that were needed for the inner diagonal were found in my scrap pile. The cabinets were assembled using PL Premium polyurethane construction adhesive and screws. Overkill perhaps, but it was what I had on my shelf and my wood glue was pretty old, so I decided I would rather be safe than sorry. I also opted for woodgrain contact paper for the appearance that I ordered from Amazon. DO NOT USE THIS STUFF! From a few feet away it looks okay, but the paper broke on the corners even though they were eased considerably with sanding. It’s very weird brittle stuff. It was cheap, but in this case, I went too cheap. It has since bubbled in places even though I meticulously applied it and rolled it with no bubbles. I had filled and sanded the wood boxes beforehand thinking I was going to paint them, so the surface was flawless and fully prepped. The product is just total crap. I plan to peel this off and go with an actual vinyl wrap or real wood veneer. The inner slopes of the middle construction needed to be arched a bit to accommodate the driver depth. During a side-off test fit, the back of the driver was so close that I felt adding an additional ½” behind the driver by bowing the wall would be easy enough to do and a good idea to ensure a problem-free fit. (I saw in the EJ Jordan designs that they actually cut this piece in two to make the fit work for their drivers.)
Tuning
After assembly I gave them a listen completely empty inside with no stuffing or damping, Yuck. Hollow, echoes, resonances, megaphone-like. Using the driver hole for access I packed bats of fill from the top peak down the channel to about 4” below the driver. At that lower end, I hot glued a piece of plastic net that I cut out of an onion bag to ensure the fill didn’t fall down over time. This took the speaker to the other extreme. Muffled, lifeless, and flat. No bueno. I removed the large amount of stuffing and went with about 1/3 as much. (I really packed it in there initially.) Now it was just lightly filled with fluffy clouds. With that, the tone was actually acceptable. Highs were there, bass was there, but some funky midrange stuff remained and had to change if I would listen to these. I found that when I draped a dish towel over the front and allowed it to flow down the slope into each speaker that an improvement was made. To make that fix permanent, I cut two 3/4” x 24” foam strips and glued them down in the throat there from about an inch below the top on back of the slope down the 24”. Yup. Almost there. Finally I dropped a single piece of craft felt that was cut to the size to the bottom of the speaker that just sits there in the bottom. In terms of what I would call listenability for tone and frequency balance, they seemed to be there. I don’t have any technical measuring devices, but to my ear they sounded flat and balanced, with nothing really stuck out.
From Meh... to OMG!
I’ve listened to the speakers for four months. They are positioned in the corners of my 12x16 living room. I was not impressed with what I was hearing at all. I employed a sub to make up for the lack of bass. The BIBs had good ‘presence’ and definitely didn’t sound like small 4” drivers... and heck, they seemed to image fine when the volume was up a bit. I got a ‘bigger’ room-filling sound than I had with my Ascend CBM170’s in the space, but… I missed some sense of separation and “sparkle.” There was like absolutely no heft or definition. Just lots of mud honestly, with a lack of dynamics. The initial period of telling myself “they just need to break in” led into a long phase of tinkering with positioning or the dampening with no discernible change. I became certain this project was just a misstep and waste of time. Even though I tried to keep my expectations low, you go into these things hoping to be surprised and that it actually works out. Well, I was about done and ready to ditch them and go back to my bookshelf speakers. Then, last week I got to pondering and wondering where I went wrong. I questioned that maybe it was the driver and I should have just used the proven Fostex units? Was it my room? I started re-reading BIB info and then it dawned on me. Maybe it isn’t the speakers at all. All along I was using a pair of 200 watt class D monoblocks that up until this point, had worked well with various speakers I own. I guess I totally forgot the point that these BIBs are highly sensitive and very easy to drive with minimal power. Well, the world of my BIB experience changed 180 degrees when I pulled a 1970’s 15 watt Kenwood receiver out of the closet and put that between my Lounge phono preamp and the BIBs. Oh. My. God. The bass! The everything! What the actual heck! Everything became unbelievably good, instantly. So much low end that you would be hard pressed to believe that I don’t have a sub sitting in the room. The mids are so clear and strong… breathtaking - and the highs are… acceptable. There is now separation and low end rumble and punch, all fullness and sparkle that I was missing. These speakers went from disappointing to absolutely freaking amazing just like that. I’m absolutely astounded. I’ve never had an experience where amplification makes this much of a crazy difference. I’m enamored with the sound I'm getting from these in the last few days. Classical rumbles with an openness, soundstage and detail that make me swear the entire orchestra is right here. Country has depth and twang, while rock has the punch and quickness that make me giggle.
I built these for a total of $110 bucks and they now knock my socks off. Now that I know these can sound so good, I have a couple more vintage receivers upstairs that I’m going to experiment with. I also want to start looking at some tube amps. I’m happy to report that this is one satisfied DIYer and want to thank all those that contributed to this thread and the BIB calculator. Hearing is believing!
Congrats! Thanks for sharing! You've gotten to the entry level of BIB/pipe horn 'goodness' .FWIW, built a lot of 'el cheapo' speakers and when they needed to be other than painted, always used wallpaper, even when a wood veneer was desired [usually bamboo], though this type doesn't come cheap, but much easier to apply/repair.
Considering the driver's low Qt specs, a matching or even 8 ohm, impedance SET amp is in theory the logical match-up, but assume this wasn't accounted for in the design/build, so one with the more common 2-2.5 ohms should yield an acceptable amount of SET 'bloom'/'lushness'.
GM
Congratulations to Scottmoose and all those who have made this the longest continually running thread on DiyAudio.
This thread began 15 years ago today and has been a great source of information and a showcase of many fun BIB builds. Keep up the good work and best wishes for many more years to come.
This thread began 15 years ago today and has been a great source of information and a showcase of many fun BIB builds. Keep up the good work and best wishes for many more years to come.
While similar in threory a BLH like the BIB is quite distinct from the horn systems they are tslkin gabout which have direct radiating woofers and mid/tweet or midTweet horn loaded on the top.
A BLH works at the lowest frequencies where the long wavelengths typicaly make for a different kind of colouration. In each case in a really well designed horn these colourations will be minimized.
In each case the range of the horn is typically less than half of the 20-20k bandwidth people often strive for.
So what Paul & Steve have to sy about horns is not applicable.
I have still yet to hear a system i enjoyed with horns on the top, but many people i respect have such systems each day.
dave
Not too shabby considering how it was received back on the original 'FR' Forum.Sheesh! From a child's birth to driver learner's permit! No wonder I feel so old!
GM
Forgot to mention that one of my most used tuning tools are a pair of cheap RadioShack [RIP] 25 ohm pots I put in series to 'dial in' the optimum 'in situ' speaker Qt @ the LP and once found, make a high SQ resistor grid with however many small ones it takes to get the desired power handling to replace them.
A lot cheaper than a SET tube amp, but retains most of the big amp's ability to accurately track the signal [transient response] Vs the SET's [mid] bass 'bloom' ['warmth'] and if nothing else will tell you how much SET output impedance you'll need.
GM
........adding a bit more WRT how all this affects the critical speech BW: EQ: Warm a Voice and Improve Clarity | Larry Jordan
GM
GM
Hi Again! I wanted to post a quick update since my last post. First, thanks for the advice and info. The wallpaper idea is a great one and I'm excited to give that a try. Replacing the failing and bad contact paper "finish" is a priority for me. Also, regarding the horn comments - I appreciate the insights. I also wonder if the "experts" comments were regarding horn drivers as well, so you cleared up some points for me. Thanks!
So... my amplification journey continues. With the comments provided, I started in earnest looking at small tube amps. Ultimately, I found the TubeCube 7 from TubeDepot.com. The price was right, the reviews were great, and I had the itch for a new piece of gear that just wouldn't go away.
It was ordered with a set of Sovtek EL84M tubes. Most every review I read or watched on that little amp mentioned how well it performed with the better tubes; so with the help of a 15% off coupon code, I went that route and installed them without even bothering with the standard ones. (maybe I'll roll them in some day this winter and see if I can hear the difference.) Anyway, I've been listening to this little amp for about a week now. I'm happy to report that it's truly magical with the Dynavox BIBs I built. As I said, the class D amp I started with was a terrible mate. A solid state vintage receiver sounded way way way better, but in comparison to this little tube amp, it is muddy and bloated. With the Tubecube 7 I get a much more open and clear experience. The bass is a little less intense, but is so perfect for these speakers. I'm getting great separation in the tracks and am hearing wonderful detail. This is absolutely a great option for this speaker. It's a wonderfully sweet combination and I highly recommend. These speakers are just so impressive - they fill our room and sound in a way that no bookshelf size ever did. It's a big, open sound that just wows!
If curious, my current chain is Technics SL-1700 (w/ AT VM95ML) > Lounge Phono Pre > TubeCube7 (with Sino 12AX7B pre & Sovtek EL84M power)> BiBs w/Dynavox LY401F.
So... my amplification journey continues. With the comments provided, I started in earnest looking at small tube amps. Ultimately, I found the TubeCube 7 from TubeDepot.com. The price was right, the reviews were great, and I had the itch for a new piece of gear that just wouldn't go away.
It was ordered with a set of Sovtek EL84M tubes. Most every review I read or watched on that little amp mentioned how well it performed with the better tubes; so with the help of a 15% off coupon code, I went that route and installed them without even bothering with the standard ones. (maybe I'll roll them in some day this winter and see if I can hear the difference.) Anyway, I've been listening to this little amp for about a week now. I'm happy to report that it's truly magical with the Dynavox BIBs I built. As I said, the class D amp I started with was a terrible mate. A solid state vintage receiver sounded way way way better, but in comparison to this little tube amp, it is muddy and bloated. With the Tubecube 7 I get a much more open and clear experience. The bass is a little less intense, but is so perfect for these speakers. I'm getting great separation in the tracks and am hearing wonderful detail. This is absolutely a great option for this speaker. It's a wonderfully sweet combination and I highly recommend. These speakers are just so impressive - they fill our room and sound in a way that no bookshelf size ever did. It's a big, open sound that just wows!
If curious, my current chain is Technics SL-1700 (w/ AT VM95ML) > Lounge Phono Pre > TubeCube7 (with Sino 12AX7B pre & Sovtek EL84M power)> BiBs w/Dynavox LY401F.
