~50 lb tapped horn, woofer under $100, high efficiency, low power?

[turbodawg]

Thanks, that sound just about perfect! Looks like it will end up being powered off a class-d car audio amp capable of 200w bridged into 4-8 ohms. Is that a free field sim? Should be plenty of bass for outdoor use with a reasonable sized group of people.

[bitSmasher]

Originally Posted by jwmbro

both of those drivers perform well in a Horn, both in the SS15 design and in the THAM12 design.

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!

[tb46]

Hi jbell,

What would the throat details be for the SS15slim?

Regards,

[turbodawg]

My update - have been modeling a few 4ohm 12" subs in hornresp, the eminence eminator 12" jbell suggests in post #6 works real nice in smaller boxes. Tried a delta-12c with no luck. I'm now trying to cram something into 3.5 cubes overall or 20x20x15....which may not be possible.

[Shadydave]

Originally Posted by turbodawg

Thanks, that sound just about perfect! Looks like it will end up being powered off a class-d car audio amp capable of 200w bridged into 4-8 ohms. Is that a free field sim? Should be plenty of bass for outdoor use with a reasonable sized group of people.

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

[1audiohack]

AGM batteries. If you can have one in the passenger compartment of an airplane it should be Ok in the house. :^)

[turbodawg]

What about deep cycle marine batteries?

[1audiohack]

I wouldn't unless it's an Absorbed Glass Mat type. These don't gas when charging or disscharging (within there design limits) and are nonspillable.

[turbodawg]

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?

[col]

Do you have WinISD? You could try a 6th order bandpass. The boxes usually turn out to be quite compact and robust. You just need something to do impedance sweeps to tune the ports.

col.