I'm interested in building a ~50 lb man-portable sub to be run off a battery powered amp, around 50-100w. What is the sweet spot between extension and efficiency here? For outdoor use.
I'm curious if using an efficient 12" pro audio (non-sub) woofer in a tapped horn is reasonable, considering the lower power and excursion.
Would probably be made from 1/2" cheap birch plywood.
I need to get horn resonse software and learn it.
You thoughts? Thanks!
I'm curious if using an efficient 12" pro audio (non-sub) woofer in a tapped horn is reasonable, considering the lower power and excursion.
Would probably be made from 1/2" cheap birch plywood.
I need to get horn resonse software and learn it.
You thoughts? Thanks!
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Cool, thanks! Would something like an Eminence Delta-12LFA 12" be workable in a scaled down version...?
Eminence Delta-12LFA 12" Low Frequency Driver 290-416
I have a design for an eminence 2512 eminator... It's half the cubic volume of the ss15.
I use this design in dance studio's. The 4ohm driver works well with HTIB's and/or mobile amps that are typically voltage challenged and want 4ohm or lower loads.
I still say the ss15 with the kappa pro 15lf2 is the ticket....
I use this design in dance studio's. The 4ohm driver works well with HTIB's and/or mobile amps that are typically voltage challenged and want 4ohm or lower loads.
I still say the ss15 with the kappa pro 15lf2 is the ticket....
Attachments
Light and LOUD
You could always get the 2Ω JBL 265F-1 15" to get the power up, also happens to be very light weight...
And possibly a small class D amp with adjustable subsonic filter...
You could always get the 2Ω JBL 265F-1 15" to get the power up, also happens to be very light weight...
An externally hosted image should be here but it was not working when we last tested it.
And possibly a small class D amp with adjustable subsonic filter...
Except for his 50lb weight limit!
My SS15 with the Kappa-Pro-LF2 weighs 34kg - that's a solid 50% over weight budget. After using the KPLF2, my personal conclusion is: definitely go Neo, it's worth the money. But your own conclusion may vary depending on the situation
Hi turbodawg,
both of those drivers perform well in a Horn, both in the SS15 design and in the THAM12 design.
If you use the SS15 design, unshrunk, in its original size, you are looking at about 117dB, down flat to 40Hz, xmax limited at 20V (50W into a nominal 8Ohm load).
You can easily shrink the width of the SS15 by about a quarter, for a 16" external width, this hardly affects performance, you are losing maybe 1dB of output, and a couple Hz of low end.
If you use the THAM12 design with either of these woofers (Warning: the THAM12 is a very tight design, before purchasing, make sure the magnet assembly of your chosen woofer even fits!), you can hit it with 28V (100W of power at 8Ohm) and are looking at nearly 120dB, but definitely not to 40Hz, more like 55Hz. and if you are using any kind of electronic music with deep frequencies, you'll probably want a protective high pass, as excursion goes up rapidly below 40Hz.
Have a look
All 4 these designs should comply with your airline-like weight restriction, however the slim SS15 with Dayton PA310 only barely - the driver is cheap, but it's heeeaaavy. If you can stretch your budget a little, consider this B&C driver:
B&C 12CL64 12" Neodymium Woofer 294-694
at less than 2kg it is super light thanks to Neo magnet, and works well in the horn designs.
I also agree with the other posters here, that for mobile usage, there is some advantage to using a lower impedance driver, as with batteries you are typically limited by the voltage your amp can supply. If you are running off mains AC, disregard that.
Wow that's awesome and amazingly helpful. I like the airline luggage analogy..."I'd like to check this please..."
This is to be part of a battery powered PA, to be transported in the back of a sedan. Just took some measurements, and it appears that 16" is too thick to fit in the trunk. 32x30x14 is about the absolute max, and 30x24x14 by looks like it would be optimal - would you say that decreasing the width by those 2" would have minimal effect on performance, while slightly increasing power handling?
The dayton pro 12" seems like a good fit, this is a budget project and has already far overgrown it's original scope, so cost containment is good. 40hz extension is just about right, and the output is plenty - is that sim'd in free space or against a wall? I'm calculating that the width decrease reduces the wood used by about 8 square ft, so that should put the total weight of the box itself around 30lb, plus the driver?
I'm starting to get excited here, thanks again!
This is to be part of a battery powered PA, to be transported in the back of a sedan. Just took some measurements, and it appears that 16" is too thick to fit in the trunk. 32x30x14 is about the absolute max, and 30x24x14 by looks like it would be optimal - would you say that decreasing the width by those 2" would have minimal effect on performance, while slightly increasing power handling?
The dayton pro 12" seems like a good fit, this is a budget project and has already far overgrown it's original scope, so cost containment is good. 40hz extension is just about right, and the output is plenty - is that sim'd in free space or against a wall? I'm calculating that the width decrease reduces the wood used by about 8 square ft, so that should put the total weight of the box itself around 30lb, plus the driver?
I'm starting to get excited here, thanks again!
Well if 24x30x14 is your ideal -- build that.
As it happens -- a ss15 is 24x30, and if you build it 14" wide and put a Dayton Audio ST305-8 12" Series II Woofer in it... you can get 120db at 100watts with just about the exact same response profile (just lower total output) as the full size ss15 version.
You are good up through 200 watts so you've got plenty of headroom available on that driver. Highpass at 30hz.
(wonder if that config should be added to the singlesheet thread as a SS15slim)
As it happens -- a ss15 is 24x30, and if you build it 14" wide and put a Dayton Audio ST305-8 12" Series II Woofer in it... you can get 120db at 100watts with just about the exact same response profile (just lower total output) as the full size ss15 version.
You are good up through 200 watts so you've got plenty of headroom available on that driver. Highpass at 30hz.
(wonder if that config should be added to the singlesheet thread as a SS15slim)
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Would you care to sim the Delta 12LFA?
Coincidentally, I'm looking to build a battery powered system and have a bunch of D12LFA on hand to build subs with. The SS15 slim sounds appealing, as portability is important... and given I'm being realistic about what to expect from a 12V system outdoors I'm not too fussed about "sub" bass so don't need anything below 60hz.
Hopefully the Eminence will be as usable!
Going to try it out inside?
If you are ever tempted to set that up inside your house, Don't bring a car battery inside.
I did just that, and one day I realized that the battery was split right in half and acid had sprayed in a line all the way up both walls and across the ceiling.
It ruined a big section of industrial tile which is now covered with a throw rug.
.
It must have made quite a thump when it blew up, but I guess I wasn't home.
.
Anyway, just don't bring batteries inside.
Dave
If you are ever tempted to set that up inside your house, Don't bring a car battery inside.
I did just that, and one day I realized that the battery was split right in half and acid had sprayed in a line all the way up both walls and across the ceiling.
It ruined a big section of industrial tile which is now covered with a throw rug.
.
It must have made quite a thump when it blew up, but I guess I wasn't home.
.
Anyway, just don't bring batteries inside.
Dave
Sooo......I ran a bunch of sims and ended up with what I thought was a pretty neat and buildable design of a folded T-TQWT in about 65L with the 12" 2512 eminator, with good extension to below 40hz, however efficiency was around 93 db/w/m (1.85v on 4ohm driver) in 2pi space. Problem is, I ran a bass-reflex sim of the same size and got shockingly identical response. OOPS.
I was also able to sim a Delta-12LFC in 85L ported completely flat to 45hz @ 95 db/w/m (1.85v). It did run out of xmax pretty quick but has huge xmech.
Granted, these are the only 4ohm drivers I was able to model that hit that kind of flat response and efficiency in 2-3 cube ported boxes. Most others were around 90 db/w/m or less.
It seems that all the compact tapped horn designs I see or model are slightly bigger and/or cut out around 55-60hz, but do hit roughly 97 db/w/m. It looks like if you want to hit 40hz in 2pi with good efficency, you pretty much have to step to something like the SS15 in a slim profile as discussed previously, but that will be around 130-140L, and efficiency will be around 97db I think? That's not that much of a gain over a Delta-12LFC.
So in a nutshell, I'm just not seeing anything that says that a TH is really the way to go given my current design goals - flat 2pi response to 40hz, modest power handling and reasonably good efficiency, size 20"x20"x15" or less (3.5 cubes overall).
I'm leaning pretty heavily towards the ported eminator right now because it will end up as a nice compact 18x18x15 box, and if built with two ports, can have one plugged for indoor use and ~25hz extension with room gain.
Is there a huge difference in a sub that maxes at 115db vs. 120db @ 1m, for modest outdoor use?
Your thoughts? Or have I missed something?
I was also able to sim a Delta-12LFC in 85L ported completely flat to 45hz @ 95 db/w/m (1.85v). It did run out of xmax pretty quick but has huge xmech.
Granted, these are the only 4ohm drivers I was able to model that hit that kind of flat response and efficiency in 2-3 cube ported boxes. Most others were around 90 db/w/m or less.
It seems that all the compact tapped horn designs I see or model are slightly bigger and/or cut out around 55-60hz, but do hit roughly 97 db/w/m. It looks like if you want to hit 40hz in 2pi with good efficency, you pretty much have to step to something like the SS15 in a slim profile as discussed previously, but that will be around 130-140L, and efficiency will be around 97db I think? That's not that much of a gain over a Delta-12LFC.
So in a nutshell, I'm just not seeing anything that says that a TH is really the way to go given my current design goals - flat 2pi response to 40hz, modest power handling and reasonably good efficiency, size 20"x20"x15" or less (3.5 cubes overall).
I'm leaning pretty heavily towards the ported eminator right now because it will end up as a nice compact 18x18x15 box, and if built with two ports, can have one plugged for indoor use and ~25hz extension with room gain.
Is there a huge difference in a sub that maxes at 115db vs. 120db @ 1m, for modest outdoor use?
Your thoughts? Or have I missed something?
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