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-   -   Single sheet TH challenge (http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge.html)

jbell 24th July 2010 06:59 PM

Single sheet TH challenge
 
Ok, so being 'never satisfied' I'm trying to better 'the cube' that I just built a few of.

Since there are several hornresp tapped horn quarterbacks that are better than I.... Here's the challenge.

1. Single 4x8 sheet of plywood. All panels, including bracing/reflectors, etc..
2. Most SPL 'area under the curve' from 40hz-140hz (minimum 100db average +-3db 1W1M)
3. Minimum 125db single cabinet from 'about' 40hz on up in 2pi space (understand, some designs in single cabinet won't 'quite' be able to hit 40hz, that's ok...)
4. Under $200 driver.

Bonus points for a better shape than a cube.

EDIT:

This section of the original post will be used for navigating this thread, and will be updated occasionally.
This sub was designed for the eminence series of drivers, 4015lf, 3015lf, Kappa Pro 15-LF2. Others work too.

cad drawing --http://www.diyaudio.com/forums/subwo...ml#post2278081
General Layout --http://www.diyaudio.com/forums/subwo...ml#post2273977
cut sheet --http://www.diyaudio.com/forums/subwo...ml#post2265677
note about using PL premium poly glue -- http://www.diyaudio.com/forums/subwo...ml#post2484469
High pass filters and excursion -- http://www.diyaudio.com/forums/subwo...ml#post2509736
First thoughts on 'cone correction' -- http://www.diyaudio.com/forums/subwo...ml#post2499741
Directivity Testing -- http://www.diyaudio.com/forums/subwo...ml#post2525499
Non US driver, (monacor) -- http://www.diyaudio.com/forums/subwo...ml#post2759432
US Drivers/PowerRatings -- http://www.diyaudio.com/forums/subwo...ml#post3193764
Nice little comparison chart -- http://www.diyaudio.com/forums/subwo...ml#post2836328
One of my favorite pics of FlipC's dozen -- http://www.diyaudio.com/forums/subwo...ml#post2528082
Quick post about construction technique -- http://www.diyaudio.com/forums/subwo...ml#post2470384

polviggen 24th July 2010 09:11 PM

the cubo15 seems to do that pretty ok.

Cubo 15

it's very easy to built, maybe try one and compare to your cube ? I built the extended version with an 3015LF and the output is pretty damn good for that size.

just remembered, the extended version can't be built out of one panel, had to use a leftover piece for that.

Brian Steele 25th July 2010 02:33 AM

Quote:

Originally Posted by polviggen (Post 2252955)
the cubo15 seems to do that pretty ok.

Cubo 15

it's very easy to built, maybe try one and compare to your cube ? I built the extended version with an 3015LF and the output is pretty damn good for that size.

just remembered, the extended version can't be built out of one panel, had to use a leftover piece for that.

Just curious - how would you go about simulating the "Cubo" design in HornResp?

djk 25th July 2010 01:56 PM

I don't buy the performance numbers presented.

http://i56.photobucket.com/albums/g1...sch/MTL-1X.gif

The larger EV MTL-1X with an 18 doesn't go as deep? Isn't as efficient?

Show me the sim !

tb46 25th July 2010 02:00 PM

Horn-vented bass reflex meets tapped horn.
 
Hi Brian,

Looks like a "horn vented bass reflex/tapped horn", see:

http://www.diyaudio.com/forums/subwo...reo-amp-6.html

Just take that Hornresp input (change to the respective numbers for driver, length and areas, if you like), and turn on TH.

Regards,

polviggen 25th July 2010 03:28 PM

1 Attachment(s)
hornresp is a bit negative on this type of enclosure. in reality it goes lower

here are the inputs i got

jbell 25th July 2010 07:49 PM

johan (rademakers) posted something VERY similar to the cubo in one of the TH threads way back.. I'm too lazy to look it up right at the moment. My problem with most of the hybrid cabinets are they are 50hz boxes, and it takes a pile of them to get to 40hz.

Because of that, I have kinda dismissed a hybrid... but maybe I should play around with a large chamber/short horn and see if there is something there I haven't seen in the past. I've also played around with compound horns at 3:1, and found something similar... Just hard to get to 40hz.

The folding is also the trick.. how to most efficiently fold with the fewest boards possible, while still having a good performing cabinet.

any creative thoughts?

polviggen 25th July 2010 09:40 PM

that probably was the cubo

Xoc1 25th July 2010 10:35 PM

3 Attachment(s)
My attempt
12mm Ply 1off 8' x 4' sheet Eminence 3015LF driver
Trouble is that as you tweek the bandwidth and efficiency you loose the low frequency extension. The only way I can see to get it back is to increase the size which would take more timber....
Maybe a longer path length would be possible if the width of the horn was reduced to 400mm:D
Spl response grey line is J Bell Mini TH for comparison.

djk 25th July 2010 10:49 PM

The 'iron law' still applies to a TH enclosure.

I don't think 40hz and 100dB are possible from a 2' cube.

50hz, yes, 40hz, no.

#9 is a good example of that at 90dB at 40hz.

"in reality it goes lower"

With room gain, I might buy that. In 2Pi or 4Pi, no way.


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