Well, how about it? Anyone have the HornResp models for the designs they posted?
The stadium horn looks good but it's the weight more so than the size that puts me off.
Sorry, so few that post here don't know what a power limited bass reflex [BR] response looks like that it didn't occur to me to describe the plots.
Anyway, the red trace is the BR and the grey one the TH, which shows significant power limited gains for the same net volume [Vb].
Hornresp doesn't account for any acoustic losses, so much/all of the peaks/dips are either much reduced or pretty much not there in reality. If you search the forum, you'll find quite a few sims Vs measurements to see how much.
The notch centered at ~56 Hz OTOH is due to the driver running out of Xmax right before its Fs, a characteristic of all point source drivers, ergo the major dip of the BR and scalloped dips of the TH are due to the driver not being able to handle full power.
Realistically, with a hi-pass, the BR can handle 200-300 W peaks whereas the TH up around 1 kW based on published specs.
That said, due to the acoustical HF inversion of the TH, it shouldn't be used much above its 3rd harmonic [the tap point], so for this alignment it's limited to a < ~ 140 Hz XO.
Anyway, import the files into HR to view/modify them.
GM
Not exactly sure what you're referring to, but in any case I would debate it's much of a flaw if the frequency response it yields is completely flat.
Jbell chose to build it in 3/4 ply" with no bracing. If you switched to 1/2" ply and used bracing effectively you could potentially drop the weight by a little less than 30%. The kappas certainly don't have enough grunt to give a reasonably braced 1/2" ply cab any trouble.
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See attached image. Look at the difference between the horn at point A and then at point B. That's a pretty big pinch. Yes, it may measure "flat", but there's no way to model that in HornResp, and I tend to have my doubts about claimed response curves that can't at least be effectively modelled before commencing a build.
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Here's my try at something for those Kappas - a 220L (net) TH (for each driver) with an Fb around 42 Hz and capable of ~123dB/1W/1M in its passband.
I used a spreadsheet to model the layout, so some tweaking can be done re panel sizes and thicknesses. I made a few assumptions in the design as well that need to be rechecked before committing this design to wood.
I used a spreadsheet to model the layout, so some tweaking can be done re panel sizes and thicknesses. I made a few assumptions in the design as well that need to be rechecked before committing this design to wood.
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Here's the sim for the SS15 with your driver. Keystone also sims good with your driver in terms of FR but poor in output. I'd stick to recommended drivers to give the KS justice. That said, I went with the LAB15-4 and made a Keystone "Lite" and am quite happy with it but I am not pro and it was my first DIY TH. I have not measured it yet but will say I think it is hits mid 30s well. You might be surprised how the SS15 does. I used EV MTL1's in the day and they are 50hz boxes like SS15 and rap and hip hop still sounded great.
Brian looks nice! Looks nice. Patiently waiting for POC3.
While I am at it. How hard is the woodworking on these cone correction designs? They look like a PITA to assemble.
Brian looks nice! Looks nice. Patiently waiting for POC3.
While I am at it. How hard is the woodworking on these cone correction designs? They look like a PITA to assemble.
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This was my process
1. Cut brace to proper shape
2. Cut panels roughly to proper size
3. Screw and glue panels to brace
4. Glue between panels
5. Put screws sideways between panels to pull them tight together
6. Add more PL
I was cutting everything with a circular saw so I didn't have the ability to make precise angle cuts. Liberal application of PL makes it not a problem. The end result has no leaks and is still ridiculously strong.
That plot looks pretty close to the SS15 plot posted by Zwiller.
I think I could live with a box aroud 24"x30"x36. 4' will fit between the wheel wells of my astro, and thos Dims I think are just a bit smaller that my old scoops. that comes out to about 354 L, but I suppose the internal bracing would subtract from that. Anyone care to try a design around those dimensions?
Thanks!
That's a Nice spreadsheet, is it availible to others or is it your secret weapon?
Thanks.
Here's one attempt. And not that this is for ONE driver.
Max SPL is still displacement-limited to 125dB around 50 Hz though. But you do get quite a bit more output between 50 Hz and 40 Hz, compared to the smaller designs.
All these are designs on paper and should really be cross-checked by someone else on this board who's "in the know" before you commit to wood
.Attachments
24x24x32 ~10.7 cubic feet - about the bulk and shape of Peavey FH1.
http://www.diyaudio.com/forums/subw...nterested-ppsl-enclosures-12.html#post2646368
port
http://www.diyaudio.com/forums/subw...nterested-ppsl-enclosures-12.html#post2646368
port
An externally hosted image should be here but it was not working when we last tested it.
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1. I haven't done a lot of these. I'm more a "spreadsheet warrior" than anything else these days. What I have built matches what I sim, but for the guys with the experience, check Art and DJK, amongst others.
2. Very big if you want 100dB @ 40 Hz
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