my buddy that is gonna be helping me this weekend now wants to build a th for himself. he has two mtx 9500 15's collecting dust. wanted to see what y'alls input is on these drivers for a th.
Fs: 31.90 Hz
Qms: 3.78
Cms: 0.066 mm/N
Mms: 375.20 g
Rms: 19.89 kg/s
Vas: 2.474 ft³ (70.04 liters)
Xmax: 1.010 in (25.65 mm)
D: 13.082 in (332.28 mm)
Sd: 134.41 in² (867.15 cm²)
Vd: 135.77 in³ (2.22 liters)
Qes: 0.79
Re: 1.71 Ω
Bl: 12.74 Tm
Prms: 1000 Watts
Qts: 0.655
ηο: 0.277 %
SPLo: 87.10 dB
SPL 2.83V/1m: 93.80 dB
Fs: 31.90 Hz
Qms: 3.78
Cms: 0.066 mm/N
Mms: 375.20 g
Rms: 19.89 kg/s
Vas: 2.474 ft³ (70.04 liters)
Xmax: 1.010 in (25.65 mm)
D: 13.082 in (332.28 mm)
Sd: 134.41 in² (867.15 cm²)
Vd: 135.77 in³ (2.22 liters)
Qes: 0.79
Re: 1.71 Ω
Bl: 12.74 Tm
Prms: 1000 Watts
Qts: 0.655
ηο: 0.277 %
SPLo: 87.10 dB
SPL 2.83V/1m: 93.80 dB
Post #80
Hi again,
Your buddy is correct, the taper @ the horn throat (right after S2) has a restriction. The opening from the chamber to the horn is centered towards the chamber, particularly if you use a 6" wide slot as shown in the drawing. I have modelled the transition into the horn with a number of different dimensions in Hornresp (changing alone and/or together S1/S2/L12/Ap1/Lpt/Vtc/Atc), and the frequency response hardly changes at all (actually, the restriction seems to improve it ever so slightly).
To get a more accurate model you would need the help of somebody who is good at Akabak (maybe MaVo, or soho54).
Cowan made a suggestion for the MTX9515 in the collaborative thread, if you were to stuff the MTX into this box S2 would be too large, it should be about 425cm^2, and then the taper from S2 to S3 would have to be reset (i.e.: same S3, same L23, different S2, different taper).
Back to work,
Regards,
Hi again,
Your buddy is correct, the taper @ the horn throat (right after S2) has a restriction. The opening from the chamber to the horn is centered towards the chamber, particularly if you use a 6" wide slot as shown in the drawing. I have modelled the transition into the horn with a number of different dimensions in Hornresp (changing alone and/or together S1/S2/L12/Ap1/Lpt/Vtc/Atc), and the frequency response hardly changes at all (actually, the restriction seems to improve it ever so slightly).
To get a more accurate model you would need the help of somebody who is good at Akabak (maybe MaVo, or soho54).
Cowan made a suggestion for the MTX9515 in the collaborative thread, if you were to stuff the MTX into this box S2 would be too large, it should be about 425cm^2, and then the taper from S2 to S3 would have to be reset (i.e.: same S3, same L23, different S2, different taper).
Back to work,
Regards,
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Throat taper/restriction
Hi nephylum,
I have tried the box in AkAbak, and the throat area seems to be fine. By the way, you may have noticed the typo in the last drawing, the spacer does not have two I.D.s, obviously it has I.D. and O.D..
If you have the time, measure the driver's T/S prior to installation to have a baseline. When the driver is installed deviations of the impedance from the model can indicate air leaks.
Let me repeat: "Take care with the woodwork, gaps and air leaks kill tapped horns. Use plenty of premium PL glue. And make large and well sealed access panel(s) for the driver. Also, add braces to suit."
Regards,
Hi nephylum,
I have tried the box in AkAbak, and the throat area seems to be fine. By the way, you may have noticed the typo in the last drawing, the spacer does not have two I.D.s, obviously it has I.D. and O.D..
If you have the time, measure the driver's T/S prior to installation to have a baseline. When the driver is installed deviations of the impedance from the model can indicate air leaks.
Let me repeat: "Take care with the woodwork, gaps and air leaks kill tapped horns. Use plenty of premium PL glue. And make large and well sealed access panel(s) for the driver. Also, add braces to suit."
Regards,
update: i had planned on going to atlanta this weekend to visit family and get my buddy to help with the th build. was unable to do soo because of difficulties with my wife's pregnancy... she's been very nauseous. anyways... plan on getting this started very soon. still gonna use tb46's design. i have a guy over at elemental design that has built 2 th's using the ed 190.v2 sub. he doesnt use hornresp... not really sure how he design the enclosure. here's a design he made for me. all i got is a pic and some cut sheets. here you go...
2 - 64" x 21 1/2"
1- 52 1/2" x 18 1/2"
1 - 49 1/4" x 20"
2 - 65 1/2" x 23"
1 - 65 1/2" x 20"
1 - 64" x 18 1/2"
2 - 23" x 21 1/2"
2 - 21 1/2" x 20"
2 - 53" x 18 1/2"
1 - 18 1/2" x 8 1/2"
1 - 18 1/2" x 8 1/8"
1 - 18 1/2" x 7"
1 - 18 1/2" x 6 5/8"
those last four pieces are the corner guides. those will get paired together and cut with 45 degree angles. the two 53" x 18 1/2" pieces are the inner baffles. those aren't going to be exactly 53" long, but they'll be pretty close once the top end is radiused. these pictures will make more sense of it. if not, i'll stay in touch with you.
2 - 64" x 21 1/2"
1- 52 1/2" x 18 1/2"
1 - 49 1/4" x 20"
2 - 65 1/2" x 23"
1 - 65 1/2" x 20"
1 - 64" x 18 1/2"
2 - 23" x 21 1/2"
2 - 21 1/2" x 20"
2 - 53" x 18 1/2"
1 - 18 1/2" x 8 1/2"
1 - 18 1/2" x 8 1/8"
1 - 18 1/2" x 7"
1 - 18 1/2" x 6 5/8"
those last four pieces are the corner guides. those will get paired together and cut with 45 degree angles. the two 53" x 18 1/2" pieces are the inner baffles. those aren't going to be exactly 53" long, but they'll be pretty close once the top end is radiused. these pictures will make more sense of it. if not, i'll stay in touch with you.
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Hi,
On a quick try in Hornresp it doesn't look too bad, better than the first one from the ED forum. The F3 is about 28Hz, below that the response falls like a rock and the excursion takes off (pretty typical for a tapped horn), the first big dip (-11dB) starts @ 87Hz, so about 1.5 octave usable range.
In Hornresp a minor improvement could be had by reducing S1, decreasing L12 and increasing the mouth area, but then that's "just" in Hornresp.
Be careful with the dimensions when cutting the wood, nominal 3/4" may be quite a bit different. I would use the extra wood for braces instead of double walls, less weight, possibly better performance. For double wall construction I like to use 1/2" thick material, and different kinds of material for inside and outside.
Regards,
On a quick try in Hornresp it doesn't look too bad, better than the first one from the ED forum. The F3 is about 28Hz, below that the response falls like a rock and the excursion takes off (pretty typical for a tapped horn), the first big dip (-11dB) starts @ 87Hz, so about 1.5 octave usable range.
In Hornresp a minor improvement could be had by reducing S1, decreasing L12 and increasing the mouth area, but then that's "just" in Hornresp.
Be careful with the dimensions when cutting the wood, nominal 3/4" may be quite a bit different. I would use the extra wood for braces instead of double walls, less weight, possibly better performance. For double wall construction I like to use 1/2" thick material, and different kinds of material for inside and outside.
Regards,
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well... no worries here. gonna use your design. you put some work in with this... i think i can trust you
For what purpose are you going to use this TH? HT subwoofer? Pro audio bass? This needs to be taken into consideration as well.
for ht and music... im about 60% music, 40% ht. im starting to think you cant have the best of both worlds with one application
What to do?
Hi nephylum,
For HT I would recommend a sub that can reach down to below 20Hz with authority. For most music that is just not necessary. What are your actual listening levels, e.g.: from a SPL meter?
It's a battle to define what is the best (?) or even what is sufficient to create the illusion. Often I have to take a step back and redefine what my goals actually are. I'm designing my "media room" right now, and hope to at least move some speakers into it before the next year has passed. I have already decided on multiple subs, to this end I just started reading the thread on the Geddes multiple small sub approach:
http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html
See the link in Post #5 for a quick practical run-down. I'm only to page 45 right now, and my head hurts. But, once you get past the semantics, there are some answers here.
I know you don't have a lot of time right now, but take a look at the link in Post #5 anyway.
Regards,
Hi nephylum,
For HT I would recommend a sub that can reach down to below 20Hz with authority. For most music that is just not necessary. What are your actual listening levels, e.g.: from a SPL meter?
It's a battle to define what is the best (?) or even what is sufficient to create the illusion. Often I have to take a step back and redefine what my goals actually are. I'm designing my "media room" right now, and hope to at least move some speakers into it before the next year has passed. I have already decided on multiple subs, to this end I just started reading the thread on the Geddes multiple small sub approach:
http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html
See the link in Post #5 for a quick practical run-down. I'm only to page 45 right now, and my head hurts. But, once you get past the semantics, there are some answers here.
I know you don't have a lot of time right now, but take a look at the link in Post #5 anyway.
Regards,
good point... i kinda figured i was gonna have to go that route. those tham15 th's look pretty nice for hifi.... 2 of those and your design for the ed driver would probably get me where i need to be. thanx for the help buddy
wow.... that looks almost identical to the design buddy at ed came up with for me. would you elaborate a little on this particular design please? driver used, specs... thanx
Early effort using HornResp v.16 and 3015LF to build a Tapped Horn for PA. For it's size and weight, it holds its own, but I like JBell's big horn better.
It doesn't need any more bracing than the four pieces in the photo. Doubling up on panels or adding bracing is not needed.
It doesn't need any more bracing than the four pieces in the photo. Doubling up on panels or adding bracing is not needed.
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The double fold that Chris/Tony built is overkill in a HT setting but not loud enough in a large hall. Tony placed it on a stage and it needed a little help.
If placed on the dance floor in front of the stage, it would have worked. I made a second version with a rotated mouth to work better in front of a
stage.
If placed on the dance floor in front of the stage, it would have worked. I made a second version with a rotated mouth to work better in front of a
stage.
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