FlipC said:
Hi FlipC and others,
I am experimenting TH with PA drivers myself (my "adventures" starts here with a Beyma 10G40 in the main TH thread, but I am having bad time getting the predicted response and impedance, so I am using this opportunity to try to pick your brains
.So, are you using manufacturer T&S parameter or did you measure them ?
I never got around measuring the actual driver and I am wondering if it is this that bit me in the ar*e.
I have not been able to find details of your build, have made your design public yet ?
Have you measured your build and is it coming close to your simulation ?
Finally, I am trying to go down to 30Hz (home HT and hifi use), yours does not seem to go this low, does it?
Finally, finally, if you can point at a good proven design (ideally one that was measured) for a TH based on a "reasonably priced" PA drivers that would go down to 30Hz that would be really great (really really).
Many thanks in advance for your answers.
myn said:
Unfortunately I doubt it can be found in Europe, but mainly, as I have been bitten in the arese a bit by a driver that would not react at all as simulated, I would really like to go for a design that is supported by measures... No offence, but I was lucky I did not buy this driver for the purpose of that horn.
brsanko - Post #44
Quote:...Try designing a TH with Tang Band's 6.5" subwoofer. You can get response flat down to 30hz and output well in exess of 120db in a box less than 1cuft!...
Would you mind sharing that design, so far nobody has gotten even remotely close to anything like that with a "Tang Band 6.5"".
Regards,
Quote:...Try designing a TH with Tang Band's 6.5" subwoofer. You can get response flat down to 30hz and output well in exess of 120db in a box less than 1cuft!...
Would you mind sharing that design, so far nobody has gotten even remotely close to anything like that with a "Tang Band 6.5"".
Regards,
I agree with brsanko - the most interesting tapped horns are the ones which use miniature drivers. I'll take three or four tapped horns with 8" or 6.5" drivers over a single tapped horn with a twelve or a ten any day.
While a 6.5" tapped horn won't shake the house, four of them will, and deliver flatter response.
I am currently using a tapped horn with an eight, two bandpass subs, and five sealed subs (a total of eight subs.)
Here's the response of a tapped horn with the TB 6.5" driver:
http://www.diyaudio.com/forums/showthread.php?postid=1787188#post1787188
Look for more posts by that author, he posted dimensions, predicted response, etc...
Very nice work I'd say!
While a 6.5" tapped horn won't shake the house, four of them will, and deliver flatter response.
I am currently using a tapped horn with an eight, two bandpass subs, and five sealed subs (a total of eight subs.)
Here's the response of a tapped horn with the TB 6.5" driver:
http://www.diyaudio.com/forums/showthread.php?postid=1787188#post1787188
Look for more posts by that author, he posted dimensions, predicted response, etc...
Very nice work I'd say!
I wasn't "blown away" by the first tapped horn that I built. While it plays very VERY low, it doesn't offer the huge efficiency I'd hoped for. It led to an interesting debate of the design's merits here:
tapped horns vs bandpass boxes
Here's a pic of the tapped horn in question:
I ran some tests on it, and found that it's not behaving like the model would predict. I did some thinking about this, and I think it's because the mouth is so small. In a 'normal' horn you can get away with this to some extent, but in a tapped horn you have the woofer itself sitting in the mouth, so it's a good idea to use a dramatic flare at the mouth.
Does that make sense? Tapped horns can still be made very VERY small, but you need to compensate for that big hunk of steel and iron that's taking up bunch of space at the mouth.
I've designed a new box that incorporates a humongous mouth. In addition, it's explicitly designed for corner loading. In fact the computer simulation assumes that the mouth extends over a foot into the room.
Here's a thumbnail of the design:
download blueprint here
All the dimensions are in the pic. The simulations were performed with the exact same box, and two different woofers. The first is a P-Audio SN-12MB which costs about $150 from Loudspeakers Plus. The second simulation is a quad of MCM 55-2421s. You can get four of them for about $120 from MCM. The MCM offers a lot more output, but the box will be a lot heavier too. The B&C 12" that's used in the TH-Mini will probably work too. Out of respect for Tom's business, I didn't offer any plans for that.
I really wasn't trying to clone the TH-Mini with this design, even though it looks *very* similar. I was just trying to improve on the design that I offered here a year ago. I've noticed that there's a lot of tapped horn designs floating around that look cool on paper, but won't actually work in the real world. It's fun to play with horn response, the tricky part is actually folding the horn and cramming it into a box. I intentionally chose dimensions that are pleasing, as the tapped horn I'm using now is ugly as sin. I'm hoping this one won't look as ridiculous as the last one!
tapped horns vs bandpass boxes
Here's a pic of the tapped horn in question:
I ran some tests on it, and found that it's not behaving like the model would predict. I did some thinking about this, and I think it's because the mouth is so small. In a 'normal' horn you can get away with this to some extent, but in a tapped horn you have the woofer itself sitting in the mouth, so it's a good idea to use a dramatic flare at the mouth.
Does that make sense? Tapped horns can still be made very VERY small, but you need to compensate for that big hunk of steel and iron that's taking up bunch of space at the mouth.
I've designed a new box that incorporates a humongous mouth. In addition, it's explicitly designed for corner loading. In fact the computer simulation assumes that the mouth extends over a foot into the room.
Here's a thumbnail of the design:
download blueprint here
All the dimensions are in the pic. The simulations were performed with the exact same box, and two different woofers. The first is a P-Audio SN-12MB which costs about $150 from Loudspeakers Plus. The second simulation is a quad of MCM 55-2421s. You can get four of them for about $120 from MCM. The MCM offers a lot more output, but the box will be a lot heavier too. The B&C 12" that's used in the TH-Mini will probably work too. Out of respect for Tom's business, I didn't offer any plans for that.
I really wasn't trying to clone the TH-Mini with this design, even though it looks *very* similar. I was just trying to improve on the design that I offered here a year ago. I've noticed that there's a lot of tapped horn designs floating around that look cool on paper, but won't actually work in the real world. It's fun to play with horn response, the tricky part is actually folding the horn and cramming it into a box. I intentionally chose dimensions that are pleasing, as the tapped horn I'm using now is ugly as sin. I'm hoping this one won't look as ridiculous as the last one!
MaVo said:
Hey Mavo,
I just tried modeling it in hornresponse, and it didn't "sync up" with what I measured. I reduced the volume of a tapped horn at the point where the woofer is, to simulate the volume it takes up, and the response barely changed.
Here's a pic of the throat of my tapped horn, you can see the woofer itself takes up a LOT of space in the mouth. And there's no mouth flare whatsoever.
I'm not convinced horn response is capable of modeling this.
Not saying that I've proved anything; it's possible that the issues with the measured response were due to something else.
Having said that, Tom Danley himself has mentioned a number of times that the "real" response of a tapped horn can vary dramatically from the modeled response.
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Well here's some pis of a very small tapped horn I designed and had built from a 5" driver from a JVC HTIB system. I will post the design I came up with for the TB 6.5 as soon as I draw it up again. I sell my computers and I have lost a few HDDs lately so I will have to model it again. As soon as I have the $50 for one of those drivers I will build it up for sure.
Attachments
If anyone wants to build a REAL monster, try using the box design I posted, but with *two* MCM woofers instead of four. Reduce the width of the box to 8.5", just wide enough to fit the drivers. Then wire them in parallel.
If you can find another sub box that can deliver that much SPL with $50 worth of woofers, I'd love to know about it.
That MCM woofer is ridiculously great in a horn. Honestly the only reason I'm going with P-Audio is to save weight. (This sub box is going into my girlfriend's car, and the only way she'd agree to a 4cf sub box was if it could be removed easily!)
http://www.mcmelectronics.com/product/55-2421
If you can find another sub box that can deliver that much SPL with $50 worth of woofers, I'd love to know about it.
That MCM woofer is ridiculously great in a horn. Honestly the only reason I'm going with P-Audio is to save weight. (This sub box is going into my girlfriend's car, and the only way she'd agree to a 4cf sub box was if it could be removed easily!)
http://www.mcmelectronics.com/product/55-2421
brsanko said:
I'd really love to find a woofer that can handle a couple of thousand watts and works in a horn. B&C has a couple of good candidates, but I keep coming back to the MCM 55-2421. Amplifiers are ridiculously cheap, and it would be fun to have a boomin' system in the car. I cloned an autotuba a few years back and fed it with an 800 watt amp, that was a lot of fun until I got sick of the sheer size of the box.
I have eight subs in my home theater, but they can't compare to the "impact" you get with a big sub in a car. It's just a whole different experience.
Post #50
Hi Patrick,
I have wondered about the end effect of the TH mouth for a while, but I always come back to the assumption, that Hornresp already accounts for end effects, and the corner loading effect as well. If it does than adding an additional spherical mouth as you illustrated would lead to an incorrect model. Bye the way, I could not read the Hornresp input screens, and the "download blueprint" link didn't work. I do like the general concept of increasing the flare rate at the mouth, that gives another degreee of freedom in the layout, and usually an increase in output level.
As to the Danley TH-Mini, the driver is mounted at the bottom of the mouth flare, this would indicate a folding scheme more along the lines of the SPUD (?). I have tried a number of different foldings, and I just cannot tame the peakiness in the response of the MCM 55-2421 unless I increase the compression beyond 3:1. I like the basically 2'*2'*set-width-to-match-sectional-areas box format for its good use of wood, and easy portability.
The task of converting a model into an enclosure drawing is made a lot easier if one has a CAD program with the ability to insert and manipulate blocks (e.g.: speakers), make multiple copies without having to redraw, rotate items, measure, etc.. I'm just using an old copy of ACAD, and cannot imagine to build anything without a CAD program anymore (did we actually do that?).
Thanks for all the inspiraton, attached a 1cft version of the TH with MCM 55-2421, not the smallest TH, but came out better than I thought it would (on paper that is).
Regards,
Hi Patrick,
I have wondered about the end effect of the TH mouth for a while, but I always come back to the assumption, that Hornresp already accounts for end effects, and the corner loading effect as well. If it does than adding an additional spherical mouth as you illustrated would lead to an incorrect model. Bye the way, I could not read the Hornresp input screens, and the "download blueprint" link didn't work. I do like the general concept of increasing the flare rate at the mouth, that gives another degreee of freedom in the layout, and usually an increase in output level.
As to the Danley TH-Mini, the driver is mounted at the bottom of the mouth flare, this would indicate a folding scheme more along the lines of the SPUD (?). I have tried a number of different foldings, and I just cannot tame the peakiness in the response of the MCM 55-2421 unless I increase the compression beyond 3:1. I like the basically 2'*2'*set-width-to-match-sectional-areas box format for its good use of wood, and easy portability.
The task of converting a model into an enclosure drawing is made a lot easier if one has a CAD program with the ability to insert and manipulate blocks (e.g.: speakers), make multiple copies without having to redraw, rotate items, measure, etc.. I'm just using an old copy of ACAD, and cannot imagine to build anything without a CAD program anymore (did we actually do that?
).Thanks for all the inspiraton, attached a 1cft version of the TH with MCM 55-2421, not the smallest TH, but came out better than I thought it would (on paper that is).
Regards,
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