Re: Eight subwoofers
It's basically an 8' x 8' platform that's about 8" tall. My couch rests on it. If you've seen the blueprints for the th-spud, it's basically the same idea.
It's not a tapped horn though; there are five subwoofers built into the platform.
In addition to that I have two bandpass subs and a tapped horn in the room.
I use a single plate amp. The power is weighted so that the platform gets a third, the TH gets a third, and the bandpass sub gets a third.
Believe it or not, the five subs run out of excursion before the tapped horn does. That's why they get the least power.
j.michael droke said:
It's basically an 8' x 8' platform that's about 8" tall. My couch rests on it. If you've seen the blueprints for the th-spud, it's basically the same idea.
It's not a tapped horn though; there are five subwoofers built into the platform.
In addition to that I have two bandpass subs and a tapped horn in the room.
I use a single plate amp. The power is weighted so that the platform gets a third, the TH gets a third, and the bandpass sub gets a third.
Believe it or not, the five subs run out of excursion before the tapped horn does. That's why they get the least power.
Has anyone created an Akabak model for dual woofers?
I threw one together this evening. It's quite an eye opener! The dual woofer design increased efficiency by almost double over the passband, and reduces third order distortion.
It's no wonder that Danley has released two tapped horns with dual woofers, and is about to release a TH with *eight* woofers. Multiple woofers work a heck of a lot better than one.
I posted the plans here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=129226&perpage=25&pagenumber=3
It might be worth creating a model with three or four woofers too.
Since modeling these is complex, this is what I do:
#1 - I create a design in horn response.
#2 - I transfer the design to Xara (a 2d design program. You can use whatever you prefer.)
#3 - Once I have a 2d model that works, I go back to horn response and change the parameters so that they agree with the 2D drawing from Xara.
#4 - Re-simulate in Horn Response, to be sure that it still looks alright.
Now the tricky part...
You have to put the segments into Excel, so that you can figure out where the taps go. It's a simple spreadsheet really.
Once you have the new segment lenghts and volumes from Excel, put them into Akabak, and check out your new Tapped Horn!
If these measure half as good as they model, I think we're going to see a lot of people using multiple wooofers...
I threw one together this evening. It's quite an eye opener! The dual woofer design increased efficiency by almost double over the passband, and reduces third order distortion.
It's no wonder that Danley has released two tapped horns with dual woofers, and is about to release a TH with *eight* woofers. Multiple woofers work a heck of a lot better than one.
I posted the plans here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=129226&perpage=25&pagenumber=3
It might be worth creating a model with three or four woofers too.
Since modeling these is complex, this is what I do:
#1 - I create a design in horn response.
#2 - I transfer the design to Xara (a 2d design program. You can use whatever you prefer.)
#3 - Once I have a 2d model that works, I go back to horn response and change the parameters so that they agree with the 2D drawing from Xara.
#4 - Re-simulate in Horn Response, to be sure that it still looks alright.
Now the tricky part...
You have to put the segments into Excel, so that you can figure out where the taps go. It's a simple spreadsheet really.
Once you have the new segment lenghts and volumes from Excel, put them into Akabak, and check out your new Tapped Horn!
If these measure half as good as they model, I think we're going to see a lot of people using multiple wooofers...
Patrick Bateman said:
I created a model for a tapped horn with four woofers. Like the dual woofer version, it seems to flatten out response at the low end and reduce sensitivity at the high end. It should be a real distortion killer. The severity of the peaks and dips is reduced also. Here's a pic from Akabak. The image at the top is a single woofer TH, the one at the bottom uses four of the same woofer. The excursion plot is at the left, and it's a bit wonky (since the minimums occur at various frequencies.)
I have a pair of Aura 10000RPM subwoofers , is it possible to make use of them in a TH? They will be used in a small room(16sq.m/~172sq.ft) so I don't need much output. I would like to use them below 60-80Hz.
Frode
Frode
Patrick Bateman said:
I have Hornresp, but I have to admit that I struggle a bit with the TH-simulations. I guess I just have to read the whole thread properly.
Anyways, I've made a simulation(probably stole it somewhere in the thread):
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.
It seems like it should be possible to get a decent result, so I'll just have to play around with Hornresp. I'm open to any suggestions.
Frode
A reverse taper seems to work well with that driver.
Not sure how it would work in reality though.
450 to 100 seems impressive. But then I'd be worried about "port" noise.
A total of 3m length.
Construction might be a problem.
Juggle it a little more and you might find a compromise you are happy with.
Not sure how it would work in reality though.
450 to 100 seems impressive. But then I'd be worried about "port" noise.
A total of 3m length.
Construction might be a problem.
Juggle it a little more and you might find a compromise you are happy with.
Assuming your specs are correct, here's a starter , .. probably want to play with a true reverse taper vs. a combination taper.Frode said:
ALso, watch for excursion.
Reverse THs work ok and can go deeper at relatively smaller sizes, at the expense of efficiency. What else is new ?
Attachments
B & C driver, PE or PS
Hi there JLH: You posted (#3338) one of the flattest responses for a TH on the thread, how's the construction comming on the version II? I looked up the spec's for the 8PE21 to see how it compared to drivers generally being used by others and found it to be a mid range driver with Xmax of 1mm (fs 87.5 hz), or are you using the woofer version 8PS21 with Xmax 5mm (fs73hz)? ... regards Michael
JLH said:
Hi there JLH: You posted (#3338) one of the flattest responses for a TH on the thread, how's the construction comming on the version II? I looked up the spec's for the 8PE21 to see how it compared to drivers generally being used by others and found it to be a mid range driver with Xmax of 1mm (fs 87.5 hz), or are you using the woofer version 8PS21 with Xmax 5mm (fs73hz)? ... regards Michael
I'm very interested in the tapped horn concept tp partner with some rear-loaded horns. (Thanks William and others for their great ideas....)
I can build the larger 2.2m version - but wanted to ask about the 'musicality' of the bigger TH verses, say, a 30Hz version?
If 'musicality' is more important than Home Theatre depth, should I err towards a 10-inch/12-inch model, vs a larger 15-inch model?
Do you get the drift of what I'm asking? I guess I'm talking about a bass horn that is fast and can suiatbly match the Lowther/Fostex upper horns.
Desired upper frequency roll-off is about 70Hz.
Kind regards.
Andrew Tilsley.
Sydney.
I can build the larger 2.2m version - but wanted to ask about the 'musicality' of the bigger TH verses, say, a 30Hz version?
If 'musicality' is more important than Home Theatre depth, should I err towards a 10-inch/12-inch model, vs a larger 15-inch model?
Do you get the drift of what I'm asking? I guess I'm talking about a bass horn that is fast and can suiatbly match the Lowther/Fostex upper horns.
Desired upper frequency roll-off is about 70Hz.
Kind regards.
Andrew Tilsley.
Sydney.
Sorry about that, I can't keep up with all that I get. Most that I do get related to audio I feel should be addressed on-line in case others might be interested.
Anyway, pretty much like the kit SD Contrabasses I used for awhile, only with apparently a lot more headroom considering they were driving into a fairly large warehouse space Vs the CBs being corner loaded in only a small fraction of it. In short, a very 'dry'/'fast' bass line easily capable of keeping up with horns while delivering gut wrenching LF SPLs.
Frankly, I was so mesmerized by the three way Unity's ability to reproduce the lightning strikes in Spider-man 2 with no discernible phase error that I didn't pay much attention to the subs other than to experience them, which is the way it should be.
Considering how badly the two CBs wrecked my house without 'breaking a sweat', I imagine just a single DTS-20 would probably be gross overkill in a typical HIFI/HT app.
All that said, the Diana Krall music DVD was virtually un-listenable it was so 'muddy', but the DVD looked fine/clean, so cut it short.
Unfortunately, the day I was at DSL Gainesville to see and hopefully 'experience', the 'MatterHorn' before it shipped out was behind on a very tight schedule, so there was no one qualified available to spend any time with me in what was obviously a prosound oriented demo 'room' (actually just some warehouse floor space defined by dark drapes to dim it for watching the huge video screen) with enough electronics and large mixing board to fill a small cube van that neither me nor Mike had a clue where to look because for sure the movie suffered no such problems and AFAIK the same DVD player was used.
WRT the movie/overall sound performance, my only complaint was the overly bright/harsh HF, but the three way mains weren't in their finished cases and we weren't sure if whatever EQ they might have was enabled, so may be fine once buttoned up, etc..
GM
Anyway, pretty much like the kit SD Contrabasses I used for awhile, only with apparently a lot more headroom considering they were driving into a fairly large warehouse space Vs the CBs being corner loaded in only a small fraction of it. In short, a very 'dry'/'fast' bass line easily capable of keeping up with horns while delivering gut wrenching LF SPLs.
Frankly, I was so mesmerized by the three way Unity's ability to reproduce the lightning strikes in Spider-man 2 with no discernible phase error that I didn't pay much attention to the subs other than to experience them, which is the way it should be.
Considering how badly the two CBs wrecked my house without 'breaking a sweat', I imagine just a single DTS-20 would probably be gross overkill in a typical HIFI/HT app.
All that said, the Diana Krall music DVD was virtually un-listenable it was so 'muddy', but the DVD looked fine/clean, so cut it short.
Unfortunately, the day I was at DSL Gainesville to see and hopefully 'experience', the 'MatterHorn' before it shipped out was behind on a very tight schedule, so there was no one qualified available to spend any time with me in what was obviously a prosound oriented demo 'room' (actually just some warehouse floor space defined by dark drapes to dim it for watching the huge video screen) with enough electronics and large mixing board to fill a small cube van that neither me nor Mike had a clue where to look because for sure the movie suffered no such problems and AFAIK the same DVD player was used.
WRT the movie/overall sound performance, my only complaint was the overly bright/harsh HF, but the three way mains weren't in their finished cases and we weren't sure if whatever EQ they might have was enabled, so may be fine once buttoned up, etc..
GM
GM said:
Sorry.
1. I want to tapped horn at 30Hz.
2. I have a speaker Ivolga 10c (Xmax 9.5mm).
3. I use hornresp but I can not build an optimal design. If you get a flat SPL is designed more like a maze or the inverse of TP. In this pulse characteristic is always bad
.Perhaps the speaker is not suitable for TP?
