i don't see much talk around other forums about Bill's designs. I have never been able to find negative feedback or actual comparisons. I have always wondered about the T39 design. I have never seen actual measurements or an AB comparison. I have seen the T48 measurements tho. there is a lot of praise on his forum in the review section, but i know everyone has their own ideas about what sounds good. i've always found good info here, so thought i would ask if anyone has experienced some of his designs, for example the T39. I've had the plans for many years, but became discouraged to build them after reading his forum. too good to be true IMO maybe. i did see that the eminence lab 12 and 15 are being installed in his sub designs now. i guess my question is Why don't we hear more about his designs?
A guy by the username MKTheater on AVS has a couple for sale very cheap. Not cause he was unhappy with them, he just moved on to 16-18" sealed subs.
If you use a block of four they are still 12dB down at 40hz with respect to 100hz.
If that is what you think you want, be my guest.
http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(1976-05%20AES%20Preprint)%20-%20Efficiency,%20Horns%20vs%20DR.pdf
Evaluation of the efficiency constant for exponential horns reveals that the horn is quite wasteful in its use of enclosed volume when compared to direct-radiator systems. The main advantage of horns lies in the realizability of rather high efficiencies in the 10% to 40% range which is beyond the capabilities of most direct radiators. Use of direct radiators in arrays increases the low frequency efficiency but not without a decrease of high frequency bandwidth. The areas discussed in this paper are illustrated by comparative experimental measurements on three low frequency systems: 1) A dual driver front loaded folded horn, 2) a single driver direct radiator vented-box system, and 3) a four-driver vented-box system consisting of a 2x2 array of a single driver system of item #2.
If that is what you think you want, be my guest.
http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(1976-05%20AES%20Preprint)%20-%20Efficiency,%20Horns%20vs%20DR.pdf
Evaluation of the efficiency constant for exponential horns reveals that the horn is quite wasteful in its use of enclosed volume when compared to direct-radiator systems. The main advantage of horns lies in the realizability of rather high efficiencies in the 10% to 40% range which is beyond the capabilities of most direct radiators. Use of direct radiators in arrays increases the low frequency efficiency but not without a decrease of high frequency bandwidth. The areas discussed in this paper are illustrated by comparative experimental measurements on three low frequency systems: 1) A dual driver front loaded folded horn, 2) a single driver direct radiator vented-box system, and 3) a four-driver vented-box system consisting of a 2x2 array of a single driver system of item #2.
The bottom folded horn speakers of this stack are the EV TL5050, as described in the above JAES article by DB Keele.
Look at that paint, just bubbling out of the wood !!!
Can't you just feel the heat ???
Look at that paint, just bubbling out of the wood !!!
Can't you just feel the heat ???
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embarrassed.... but no..... the only other pic is after the fire trucks left.
I think I put too much gasoline/used oil on them as my way of venting my frustration....
All I have is the burn marks, where it almost got out of control... now you know the rest of the story....
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Hi!
Made some of BF designs: Table Tuba (ok in the corner), snail, DR10 (good), DR12 (good but big), DR8 (-), Davids (ok but big for what you earn), Tuba 24 (ok in corner gift for a friend), 2 Tubas 36 (see pictures bellow self explanatory).
Beside mistakes very satisfied with TLAH threeway variation using 8 x 6", 8 x cone tweeters, + 2 alnico Selenium horn tweeters TS10A
Regards,
Made some of BF designs: Table Tuba (ok in the corner), snail, DR10 (good), DR12 (good but big), DR8 (-), Davids (ok but big for what you earn), Tuba 24 (ok in corner gift for a friend), 2 Tubas 36 (see pictures bellow self explanatory).
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Beside mistakes very satisfied with TLAH threeway variation using 8 x 6", 8 x cone tweeters, + 2 alnico Selenium horn tweeters TS10A
An externally hosted image should be here but it was not working when we last tested it.
Regards,
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I say this at the risk of being the biggest grave robber of threads. I do have a BFM background and built a couple of his tops (OT12), but I'm not here to say BILL IS GOD! DON'T DISS! like a few people have done on different threads and forums.
I haven't heard either the Tuba 24 or Tuba 30, but from my trawling the web and looking on the SPL charts, it seems like they are built to get the longest possible horn into a small box. I wasn't all that impressed with the graph for the Tuba 24 dipping down to 90dB in the lower region. An 8 cubic foot vented box could be at least 98dB to 40Hz. I have however worked out what Bill was trying to do with the design. The Tuba 30 was built for extension to nearly 30Hz, but be 'small' for a horn. This requires a long horn, and at the end of the Tuba 30 is a sudden flare, which I doubt the sound wave follows round properly. BUT, I'm sure you're familiar with the V-Coupler. I believe the box was designed to be used with it, as it takes care of the 'sudden flare' problem. From that perspective it's actually quite genius, WHY BUILD THE BIG MOUTH INTO THE HORN WHEN YOU CAN FLAT PACK IT!? Beat that Hoffman Iron. But yeah, don't bother with the Tubas if you only build one.
JBell, the SPL chart for the widest Titan 48 (36 inch) with a 3015lf does what your giant tapped horns do by the looks of it, with a limit of 60V, and with extra sensitivity up top that you could always EQ down. The Tuba 36 which I'm not familiar with was not built for maximum sensitivity above 40Hz. It's another design to be used in groups with a V-Plate to get down to the upper 20s. (even though I believe you looked at an SPL chart on the forum which was wrong at the time.)
Making a Titan too narrow with the 3015lf can restrict the middle of the pass band. They like a lot of room. Although the plans say you could build them as narrow as 18, with 24 being a popular width I'd recommend at least 30 inches. Simulations with vented boxes dictate you give them the same room as a lot of 18s! The Titans don't roll off as much as the Tubas with only one box.
And lastly front loaded horns just DO roll off down low. They are actually optimized for a higher pass band. They might not be the most efficient low bass producers for their size. There's a reason the Tapped Horn was invented. I wouldn't recommend the Tuba 24, when I believe a vented box of the same size is more efficient. A 6.6 cubic foot vented box with a Kappalite 3015lf tuned to 40Hz sims on Hornresp is 98-99dB efficient throughout the pass band! Displacement limit is in the upper 40s Voltage, which you'd need a pretty decent 10 or pair to keep up. Mention that on the forum though and I'm sure they'll say you're in David McBean's fantasy land. (I don't know whether the Tuba 24s will win when you use lots of them, 4-8 or V-Plate.)
According to my plans though, a 20 inch Titan 39 with an 18Sound NLW9300 is 101dB flat to 50Hz with a 70V limit. Start adding extra cabs, V-Plates and corners and things begin to get interesting.
Unfortunately I have to say most of this from a theory and internet review stand point. I have heard Titan 39s V-Plated front stage in conjunction with a Tuba 60 crossed at 60Hz in the corner. This worked quite well, resonating the club bathroom at fairly low levels, but I don't know what power levels they were at or what EQ so that's not very useful. They did sound very clean, but the concrete resonant room let down the 'punchiness' compared to listening in a grass tent.
Lastly, quite a bit of the advertising on the site is exaggerated and misleading - like the Tuba with 800 watts outpowering a vented 18 box with 100 watts.
********! (Paul Klipsch), although a group of V-Plated Titans might do the claim.
You can't get the efficiency unless you have a bigger cab, so if you think that a single Tuba 24 is going to be some 8 cubic foot 108dB 40Hz to 100Hz bass monster from that claim, you'll be sorely disappointed.
I haven't heard either the Tuba 24 or Tuba 30, but from my trawling the web and looking on the SPL charts, it seems like they are built to get the longest possible horn into a small box. I wasn't all that impressed with the graph for the Tuba 24 dipping down to 90dB in the lower region. An 8 cubic foot vented box could be at least 98dB to 40Hz. I have however worked out what Bill was trying to do with the design. The Tuba 30 was built for extension to nearly 30Hz, but be 'small' for a horn. This requires a long horn, and at the end of the Tuba 30 is a sudden flare, which I doubt the sound wave follows round properly. BUT, I'm sure you're familiar with the V-Coupler. I believe the box was designed to be used with it, as it takes care of the 'sudden flare' problem. From that perspective it's actually quite genius, WHY BUILD THE BIG MOUTH INTO THE HORN WHEN YOU CAN FLAT PACK IT!? Beat that Hoffman Iron. But yeah, don't bother with the Tubas if you only build one.
JBell, the SPL chart for the widest Titan 48 (36 inch) with a 3015lf does what your giant tapped horns do by the looks of it, with a limit of 60V, and with extra sensitivity up top that you could always EQ down. The Tuba 36 which I'm not familiar with was not built for maximum sensitivity above 40Hz. It's another design to be used in groups with a V-Plate to get down to the upper 20s. (even though I believe you looked at an SPL chart on the forum which was wrong at the time.)
Making a Titan too narrow with the 3015lf can restrict the middle of the pass band. They like a lot of room. Although the plans say you could build them as narrow as 18, with 24 being a popular width I'd recommend at least 30 inches. Simulations with vented boxes dictate you give them the same room as a lot of 18s! The Titans don't roll off as much as the Tubas with only one box.
And lastly front loaded horns just DO roll off down low. They are actually optimized for a higher pass band. They might not be the most efficient low bass producers for their size. There's a reason the Tapped Horn was invented. I wouldn't recommend the Tuba 24, when I believe a vented box of the same size is more efficient. A 6.6 cubic foot vented box with a Kappalite 3015lf tuned to 40Hz sims on Hornresp is 98-99dB efficient throughout the pass band! Displacement limit is in the upper 40s Voltage, which you'd need a pretty decent 10 or pair to keep up. Mention that on the forum though and I'm sure they'll say you're in David McBean's fantasy land. (I don't know whether the Tuba 24s will win when you use lots of them, 4-8 or V-Plate.)
According to my plans though, a 20 inch Titan 39 with an 18Sound NLW9300 is 101dB flat to 50Hz with a 70V limit. Start adding extra cabs, V-Plates and corners and things begin to get interesting.
Unfortunately I have to say most of this from a theory and internet review stand point. I have heard Titan 39s V-Plated front stage in conjunction with a Tuba 60 crossed at 60Hz in the corner. This worked quite well, resonating the club bathroom at fairly low levels, but I don't know what power levels they were at or what EQ so that's not very useful. They did sound very clean, but the concrete resonant room let down the 'punchiness' compared to listening in a grass tent.
Lastly, quite a bit of the advertising on the site is exaggerated and misleading - like the Tuba with 800 watts outpowering a vented 18 box with 100 watts.
********! (Paul Klipsch), although a group of V-Plated Titans might do the claim.
You can't get the efficiency unless you have a bigger cab, so if you think that a single Tuba 24 is going to be some 8 cubic foot 108dB 40Hz to 100Hz bass monster from that claim, you'll be sorely disappointed.
Djk I read your link, it confirms what I got with the Tuba 24 vs Vented Box comparison. Some designs definitely get closer to Hoffman Iron Law limits than others. The Cerwin Vega L36 seems like an even bigger space waster in this regard, just going on the forum to look up T24 charts, but it also seems like the Yamaha and Mackie cabs aren't that efficient either, compared to what's possible with vented boxes.
I believe this is the reason Tom Danley built the tapped horn. I read his white paper. He claims it's the same efficiency to space ratio as a vented box with an optimal driver, but that he can use a driver with higher power handling because it doesn't have to be so big and lightweight. An 8 cubic foot compact vented 18 I designed might be limited to about 126dB (displacement calculated with 10mm Xmax on an average correct spec 18). Imagine being able to put a bigger amp on the cab without blowing it so you could get to 130+dB out of the same sized cab!
The charts for the Simplexx series are out now too, but I believe the falling off response of the Simplexx 15 Sub (similar to the horns) is the mark of a vented box that is too small. Same with the Simplexx 18 Sub. It also seems the JBL subs in the comparison aren't very efficient compared to what I've been able to at least model in Hornresp. I built a 3.3 Cu ft box with a 3012lf tuned to 41Hz that was 95-96dB flat to 40Hz, compared to the JBL 15 which doesn't go as low (but probably handles more power).
As Bill's been designing speakers far longer than I have, I'm not sure what's to be gained from that, higher displacement limit? although he may be more used to designing horns? His Omni 15 sub though doesn't roll off like that though, so it's evidenced he can design vented boxes just fine.
Whenever I design a vented box, I make it slightly LOUDER at the tuning frequency with a larger box, and also a strong enough motor on the driver to push the velocity minima at tuning, and be reactant enough to reduce the excursion peak (which would otherwise be the limiting factor). I'm basically making the most of output where there's room to spend a bit of displacement, and reducing it where it would be the limiting factor.
That's a tragic flaw of the vented box, not being able to get much more output/extension without more displacement. This is where horn designs win, getting the most out of a driver, space no object of course. Also that you need a large lightweight driver to get close to the efficiency potential, especially in the upper bass. Try making a VB for a Lab 15 if you don't know what I mean.
I believe this is the reason Tom Danley built the tapped horn. I read his white paper. He claims it's the same efficiency to space ratio as a vented box with an optimal driver, but that he can use a driver with higher power handling because it doesn't have to be so big and lightweight. An 8 cubic foot compact vented 18 I designed might be limited to about 126dB (displacement calculated with 10mm Xmax on an average correct spec 18). Imagine being able to put a bigger amp on the cab without blowing it so you could get to 130+dB out of the same sized cab!
The charts for the Simplexx series are out now too, but I believe the falling off response of the Simplexx 15 Sub (similar to the horns) is the mark of a vented box that is too small. Same with the Simplexx 18 Sub. It also seems the JBL subs in the comparison aren't very efficient compared to what I've been able to at least model in Hornresp. I built a 3.3 Cu ft box with a 3012lf tuned to 41Hz that was 95-96dB flat to 40Hz, compared to the JBL 15 which doesn't go as low (but probably handles more power).
As Bill's been designing speakers far longer than I have, I'm not sure what's to be gained from that, higher displacement limit? although he may be more used to designing horns? His Omni 15 sub though doesn't roll off like that though, so it's evidenced he can design vented boxes just fine.
Whenever I design a vented box, I make it slightly LOUDER at the tuning frequency with a larger box, and also a strong enough motor on the driver to push the velocity minima at tuning, and be reactant enough to reduce the excursion peak (which would otherwise be the limiting factor). I'm basically making the most of output where there's room to spend a bit of displacement, and reducing it where it would be the limiting factor.
That's a tragic flaw of the vented box, not being able to get much more output/extension without more displacement. This is where horn designs win, getting the most out of a driver, space no object of course. Also that you need a large lightweight driver to get close to the efficiency potential, especially in the upper bass. Try making a VB for a Lab 15 if you don't know what I mean.
At least once every two years we need to be inspired to roast some hot dogs. Nathan's are best. Hebrew National a close second. One day, maybe one two, four or six years there will be a great big bonfire which can be seen from space when I decommission 8 lab horns. Some time when I have time to build the eight slightly larger 4x4x28" FLH boxes loaded with TBW18's that it would take to 'upgrade'. When space really IS no object things can get quite flat, and not have the +12dB honk. I found this single box sim to be quite compelling, maybe enough to go slap something together out of OSB this spring.
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What horn/voltage input is that?
BTW my opinion on the BFM subwoofers is that the V-Plate should be treated as part of the horn ESPECIALLY with the 'box' Tuba cabs. I think the reason the T36 got decommissioned is because it is such a big cab that not everyone has the room for 2 and a V-Plate, whereas the T60 and Titans will work better alone, although they'll still have the roll off. If you have room for only one Tuba 30/24 you'd be better served with a design that doesn't have the 'home theatre subwoofer + kick bin' response.
The failure to get completely flat even in large groups could be something to do with:
A: Not using the V-Plate
B: Like most designs they are quarter wave horns instead of enormous half wave horns.
C: Too narrow a cab for the 3015lf to breathe - it is a 'large box' driver not a high compression horn driver, thus wide low compression horns are its forte. Think JBell's set of 4 tapped horns. Low compression means this driver blooms, unlike a Lab 12 which I'd say is a fairly poor vented box driver outside of say a car or living room.
The thread may be old but the designs haven't changed much and there are a few new ones. There seems to be a lack of up to date threads in this forum anyway.
BTW my opinion on the BFM subwoofers is that the V-Plate should be treated as part of the horn ESPECIALLY with the 'box' Tuba cabs. I think the reason the T36 got decommissioned is because it is such a big cab that not everyone has the room for 2 and a V-Plate, whereas the T60 and Titans will work better alone, although they'll still have the roll off. If you have room for only one Tuba 30/24 you'd be better served with a design that doesn't have the 'home theatre subwoofer + kick bin' response.
The failure to get completely flat even in large groups could be something to do with:
A: Not using the V-Plate
B: Like most designs they are quarter wave horns instead of enormous half wave horns.
C: Too narrow a cab for the 3015lf to breathe - it is a 'large box' driver not a high compression horn driver, thus wide low compression horns are its forte. Think JBell's set of 4 tapped horns. Low compression means this driver blooms, unlike a Lab 12 which I'd say is a fairly poor vented box driver outside of say a car or living room.
The thread may be old but the designs haven't changed much and there are a few new ones. There seems to be a lack of up to date threads in this forum anyway.
I did a THEORETICAL comparison on 3 x 190 litre total internal volume Vented boxes tuned to 41.5Hz vs a 36 inch wide T48. Each box had a Kappalite 3015lf.
With 1.63 Volts to each of the vented boxes and 2.83 V to the Titan 48, the Titan came out on top in the upper bass, and similar performance in the lower bass.
The Titan can take 60 Volts, whereas the Vented boxes are each displacement limited to 48, or a power equivalent of 83 Volts for 3 cabs. Using an 18 Sound 15LW9300, the Titan could take 80 Volts, and is slightly more sensitive by 1dB. (Not sure in a wider cab).
With the premium driver that would give the Titan the same lower bass output with more upper bass. It is more expensive, but still way cheaper than 3 x 3015LF. Using a V-Plate with the widest width T48s could still be quite good even when it comes to pack space.
With 1.63 Volts to each of the vented boxes and 2.83 V to the Titan 48, the Titan came out on top in the upper bass, and similar performance in the lower bass.
The Titan can take 60 Volts, whereas the Vented boxes are each displacement limited to 48, or a power equivalent of 83 Volts for 3 cabs. Using an 18 Sound 15LW9300, the Titan could take 80 Volts, and is slightly more sensitive by 1dB. (Not sure in a wider cab).
With the premium driver that would give the Titan the same lower bass output with more upper bass. It is more expensive, but still way cheaper than 3 x 3015LF. Using a V-Plate with the widest width T48s could still be quite good even when it comes to pack space.
Hornresp adds low frequency sensitivity to ALL designs whe using the "multiple speaker" function. In reality this only happens with FLHs, thus comparing multiple vented boxes to a single horn results in an unfair advantage to the vented enclosure.
" In reality this only happens with FLHs, "
Incorrect.
JBL measures in an anechoic chamber and publishes the data comparing 4pi vs 2Pi on several models. The transition is smooth and ramps up to about 5dB of difference going down from 200hz to 100hz.
Incorrect.
JBL measures in an anechoic chamber and publishes the data comparing 4pi vs 2Pi on several models. The transition is smooth and ramps up to about 5dB of difference going down from 200hz to 100hz.
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