Thank you Mr. Bateman,
I had not yet looked at the displacement, something I usually do.
That driver would indeed need a filter if used, or a redesign.
I'm still looking to construct several small, inexpensive TH for use in a distributed multi-sub setup.
I'll have to tinker with the design, or try another driver.
John
I had not yet looked at the displacement, something I usually do.
That driver would indeed need a filter if used, or a redesign.
I'm still looking to construct several small, inexpensive TH for use in a distributed multi-sub setup.
I'll have to tinker with the design, or try another driver.
John
Attachments
Greets!
Except for the driver hanging off the end of the mouth (a no-no AFAIK), I see nothing fundamentally wrong with it IF its HF peak isn't nearly as pronounced as it is.
WRT the other HF 'spikes', builders say it's not nearly as bad as it sims and of course damping around the driver on the throat side will lower it even more, so combined with the XO slope it's a non-issue.
WRT impedance, as long as the amp is rated for a nominal 4 ohms at whatever power you want, then it shouldn't be a problem.
WRT the ~300 L sim, this driver's theoretical usable band-pass BW based on the specs you used is only ~30-122 Hz (conic TH referenced to your 'shadow' TP), so don't have a clue if it will perform close enough to the sim. Only one way to know for sure.
All that said, I promoted tapped pipes (TP) way back in this thread and only one person AFAIK tried one and it was a dismal performer, but he 'vanished' without updating us on whether or not it leaked (even a tiny one can potentially ruin a pipe's/horn's performance) or if the published specs were off much. WRT the latter, if the specs you used are just published ones, then considering the brand, odds are you'll have to heavily damp the pipe (or horn), potentially severely reducing peak output (dynamic headroom) to flatten it out, so Caveat Emptor applies.
Please keep us updated as time permits as we can't have too much documented 'hands on' experience.
GM
Except for the driver hanging off the end of the mouth (a no-no AFAIK), I see nothing fundamentally wrong with it IF its HF peak isn't nearly as pronounced as it is.
WRT the other HF 'spikes', builders say it's not nearly as bad as it sims and of course damping around the driver on the throat side will lower it even more, so combined with the XO slope it's a non-issue.
WRT impedance, as long as the amp is rated for a nominal 4 ohms at whatever power you want, then it shouldn't be a problem.
WRT the ~300 L sim, this driver's theoretical usable band-pass BW based on the specs you used is only ~30-122 Hz (conic TH referenced to your 'shadow' TP), so don't have a clue if it will perform close enough to the sim. Only one way to know for sure.
All that said, I promoted tapped pipes (TP) way back in this thread and only one person AFAIK tried one and it was a dismal performer, but he 'vanished' without updating us on whether or not it leaked (even a tiny one can potentially ruin a pipe's/horn's performance) or if the published specs were off much. WRT the latter, if the specs you used are just published ones, then considering the brand, odds are you'll have to heavily damp the pipe (or horn), potentially severely reducing peak output (dynamic headroom) to flatten it out, so Caveat Emptor applies.
Please keep us updated as time permits as we can't have too much documented 'hands on' experience.
GM
Attachments
I searched this mega-thread but didn't see anything about using a 15" LMS-Ultra in a TH. Horn subs are a new thing to me, and Hornresp beat me like a rented mule. Is this driver suitable with the following parameters(dual 2 ohm VC)? I am looking for the lowest possible frequencies with decent output. I have the higher bass frequencies covered if need be.
Qts .341
Qes .367
Qms 4.786
Fs 22.951
Res 3.9
Ls 2.252
Lp 4.459
Rp 2.727
Vas 107.3L
mms 460g
cms 104.5
bl 26.55
n0 340
Sens 87.31
Sd .082m^2
Xmax 38mm
power handling 5000W
Qts .341
Qes .367
Qms 4.786
Fs 22.951
Res 3.9
Ls 2.252
Lp 4.459
Rp 2.727
Vas 107.3L
mms 460g
cms 104.5
bl 26.55
n0 340
Sens 87.31
Sd .082m^2
Xmax 38mm
power handling 5000W
Idea for experimental tapped horn
Hello, gentlemen! If I may impose upon you for a moment to look at my design, and see if it's practical. You see, before I try my hand at a larger tapped horn, I want to make sure I understand the principals by building this miniscule experimental project. If I like the results, I may add an amp like this one and use it as a computer subwoofer. I do realize that it leaves something to be desired, but it should suffice as proof of concept; my main concern is the negative flare in section 1, but I can live with it if it works.
Hello, gentlemen! If I may impose upon you for a moment to look at my design, and see if it's practical. You see, before I try my hand at a larger tapped horn, I want to make sure I understand the principals by building this miniscule experimental project. If I like the results, I may add an amp like this one and use it as a computer subwoofer. I do realize that it leaves something to be desired, but it should suffice as proof of concept; my main concern is the negative flare in section 1, but I can live with it if it works.
Attachments
Fatawan said:
Now that's a heck of a whooping!
Well, it has a theoretical 4.25 Hz LF corner frequency, but I doubt you want to build such a room size TH. Anyway, if the specs are reasonably accurate and assuming series VC, 4 mH of inductance, 2 pi space, 1 W, then just 'running the numbers', the low tuned one is 11.48 Hz Fp/518.66 L net and in shadow is the small one at 16.22 Hz Fp/265.6 L net. Tune higher to further shrink its bulk/increase efficiency and vice versa:
GM
Attachments
GM said:
Now that's a heck of a whooping!
Well, it has a theoretical 4.25 Hz LF corner frequency, but I doubt you want to build such a room size TH. Anyway, if the specs are reasonably accurate and assuming series VC, 4 mH of inductance, 2 pi space, 1 W, then just 'running the numbers', the low tuned one is 11.48 Hz Fp/518.66 L net and in shadow is the small one at 16.22 Hz Fp/265.6 L net. Tune higher to further shrink its bulk/increase efficiency and vice versa:
GM
Thank you GM. That actually looks quite interesting to do an 18.3 cu. ft box. The specs are Praxis measured for this particular driver that I have in hand. I will now have to go and read up on what all those parameter inputs mean, and what I would end up with. Would a typical home theater pre/pro crossover at 80Hz or so be a good or bad thing with a tapped horn? How about the actual build--Hornresp gives me a Swiss Mountain horn-looking picture. Is there something that would give a folded horn model that could be built in a reasonable size? As you can tell, I am as green as green can be.
GM said:
Now that's a heck of a whooping!
Well, it has a theoretical 4.25 Hz LF corner frequency, but I doubt you want to build such a room size TH. Anyway, if the specs are reasonably accurate and assuming series VC, 4 mH of inductance, 2 pi space, 1 W, then just 'running the numbers', the low tuned one is 11.48 Hz Fp/518.66 L net and in shadow is the small one at 16.22 Hz Fp/265.6 L net. Tune higher to further shrink its bulk/increase efficiency and vice versa:
GM
Hi GM-
I'm still getting my mind around TH's as well, but are there concerns about the compression ratio being that high (~ 4.5:1) when using a driver with as much displacement as this one?
Fatawan said:
Given that you see the first peaks in the 60 - 80 Hz range (large - small), I assume you'd have to use a lower crossover with a pretty high slope. While the conventional wisdom says that the peaks aren't as large as shown in HornResp, it seems like they'd still be pretty objectionable.
Volvotreter's folding guide is here:
http://www.volvotreter.de/downloads/Folding_a_Tapped_Horn.pdf
Also, having pondered the notion of building a dedicated, high output 15 - 50 Hz TH, the MTX Thunder T9515-04 is worth a look as well. It seems to perform well in Danley's TH-50, and there are HornResp suggestions from Bill Cowan in post #699.
Keith
For the car...
Testing my tapped horn in my car gave me a real taste for bass and I miss it so now I need a sub for the car. I want to use the same driver (tang band w6-1139si) and the car is only really capable of putting out enough power for 1 of them.
I found it impossible to get a rising response w/ high(ish) tuning for this driver in a tapped horn, the fs is just way too low. The only way I could get ~6db rising response with my desired tuning was to put it in a FLH, shown below in .5 pi (which should be conservative in the trunk of a car), a couple mil short of xmax with 300w, 75L. I'm not at all scared to try to tackle an expo flare.
Compression ratio is 4:1 but I think this driver is pretty rugged. Besides, my tapped horn is already loud enough, this horn promises an extra 10 db at least due to the much higher tuning and massive (for a 6.5 inch driver) Vb. 300w is a lot more than this driver is rated for but it won't be cranked much at all, and not for very long, and if the motor is on the throat side it should stay plenty cool for above normal (but not prolonged max) usage. 75L is pretty big for this driver, but on paper it looks like this thing would spank the average ported 12.
My intent is not to discuss FLH's here, but I'm interested to see if anyone can beat this with a tapped horn - same driver, 80L limit. If so please post it here. I couldn't even come close, especially up near 80 hz.
OTOH, since I am not a wise FLH designer, PLEASE pm me if you see any major problems with this design, or if you can do better, or better yet, show me how to make it better.
Testing my tapped horn in my car gave me a real taste for bass and I miss it so now I need a sub for the car. I want to use the same driver (tang band w6-1139si) and the car is only really capable of putting out enough power for 1 of them.
I found it impossible to get a rising response w/ high(ish) tuning for this driver in a tapped horn, the fs is just way too low. The only way I could get ~6db rising response with my desired tuning was to put it in a FLH, shown below in .5 pi (which should be conservative in the trunk of a car), a couple mil short of xmax with 300w, 75L. I'm not at all scared to try to tackle an expo flare.
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.
Compression ratio is 4:1 but I think this driver is pretty rugged. Besides, my tapped horn is already loud enough, this horn promises an extra 10 db at least due to the much higher tuning and massive (for a 6.5 inch driver) Vb. 300w is a lot more than this driver is rated for but it won't be cranked much at all, and not for very long, and if the motor is on the throat side it should stay plenty cool for above normal (but not prolonged max) usage. 75L is pretty big for this driver, but on paper it looks like this thing would spank the average ported 12.
My intent is not to discuss FLH's here, but I'm interested to see if anyone can beat this with a tapped horn - same driver, 80L limit. If so please post it here. I couldn't even come close, especially up near 80 hz.
OTOH, since I am not a wise FLH designer, PLEASE pm me if you see any major problems with this design, or if you can do better, or better yet, show me how to make it better.
Fatawan said:
You're welcome!
Thanks for the data. Can't have too many measured specs.
Yes, this driver and the sims I did have enough gain BW to handle an 80 Hz with at least a 2nd order XO, so it's just a matter of getting the in-room response flat enough using acoustic and/or electronic EQ.
Sorry, I don't do complete designs, but there's been a number of TH fold designs posted that can be adapted to suit your needs or if you know someone with 3D Cad experience, then a technically optimum one can be calculated.
GM
HornsKeith said:
Greets!
Don't have a clue since I've yet to build/test any THs other than a driver-in-mouth compound horn several decades ago and since I used a compression driver, its gain was so high I didn't need to worry about over-excursion in a HIFI app.
For prosound compression horns, Tom Danley recommends around 3:1 max, so I assume the same holds for a TH, but until someone proves otherwise, IMO somewhat higher CRs can be used in HIFI apps, though with really high excursion drivers its non-linearity with increasing excursion may become audible and/or shorten its life-span if pushed to its limits on a regular basis.Depends on the damping used. Check out gietmans' 'adventures in TH damping' starting here: http://www.diyaudio.com/forums/showthread.php?postid=1788175#post1788175
GM
Just a guy:
I just built something you may like, It's a FLH, but the drivers are in the bottom/back of the cabinet. The access panel is the mouth, so... remove the access cover and it's a TH, put the cover on, and it's a FLH. (thought it was clever) However, being designed as a FLH, response is lacking in the 80hz range when measured as a TH... putting the cover on cures that.
Anyway, I built it with some scraps, so I couldn't build it as tall/long of a path as I had simm'd, so it has the rising response you are looking for in car. Overall dimension is 21x24x31, in a 'M' fold.
Here's my outdoor (2pi) measurements, pair of mcm 55-2421's in series (8 ohm) with 2.83 volts input, sine wave, 1M.
I'm thinking of calling it a van halen sub... would be great for 80's music, ran it up to 40volts with no issues so far. 1/8th space would be downright impressive...
40 95
43 96.5
46 97
50 97.5
53 98.5
57 99.5
62 102.5
66 105
71 106.5
76 105.5
82 104
88 102.5
95 101.5
102 101
109 107
117 109
126 109
135 105
145 101
156 97
I just built something you may like, It's a FLH, but the drivers are in the bottom/back of the cabinet. The access panel is the mouth, so... remove the access cover and it's a TH, put the cover on, and it's a FLH. (thought it was clever) However, being designed as a FLH, response is lacking in the 80hz range when measured as a TH... putting the cover on cures that.
Anyway, I built it with some scraps, so I couldn't build it as tall/long of a path as I had simm'd, so it has the rising response you are looking for in car. Overall dimension is 21x24x31, in a 'M' fold.
Here's my outdoor (2pi) measurements, pair of mcm 55-2421's in series (8 ohm) with 2.83 volts input, sine wave, 1M.
I'm thinking of calling it a van halen sub... would be great for 80's music, ran it up to 40volts with no issues so far. 1/8th space would be downright impressive...
40 95
43 96.5
46 97
50 97.5
53 98.5
57 99.5
62 102.5
66 105
71 106.5
76 105.5
82 104
88 102.5
95 101.5
102 101
109 107
117 109
126 109
135 105
145 101
156 97
Rademakers said:
Yes, I tried. You can improve the 80 hz range by about 2 or maybe even 3 db at most, but nothing even close to the FLH I posted. But I encourage you to try for yourself.
jbell said:
Yeah, the infamous 80 hz range - aka the area right before the first of the 2 large TH peaks. This is the main reason I don't think a TH is appropriate for this application.