I am in no hurry, I am currently using a couple JBL JRX "subs" now and getting by. Just have the bug to build something better for outdoor stuff in the future.
I personally like GoNest 2D a lot. You can keep on using it for free, only printing and exporting is blocked (i just make print-screens). It is reasonably easy te work with, has all features needed.
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WTH?! For some odd reason I go back and start comparing sims THAM15, SS15, and this design and there's not much difference at all. I mostly used the PA385 but tried a few others. Basically all are 95db @ 40Hz. WTH? Maybe HR updates? Prior to this, Don's design clearly reached lower the THAM15 or SS15... It's clear by his post that Don's intent was to go lower than SS15/cubo too and my memory matches Brian's comparison in post 12 (4 pack 10db more at 40Hz) Am I losing it, can some one check this out?
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JRX118s. I picked them up at a garage sale. The carpet and corners were beat up and one looked like a drunk puked on it but they functioned good. A few cab corners and black dye and they look good enough to flip for a buck once I have new cabinets ready to go.
Not laughing at ya, laughing because you used quotes calling them "subs". $100 a pair was a good deal. These are pretty much what I see locally and the band guys think 4 is a big rig.
Ya, I used to run 4 of the JRX118s and the 2x15 jrx top. What a big heavy dog of a system that was. I got the whole system for under $900 but got tired of moving it around every weekend. I built a couple BFM SLA Pros and they perform better down to 100 than those 2x15 beasts.
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That's not too surprising - LF efficiency is primarily a function of the box volume.
What you've got to look at also is the delta between the 40 Hz point and the passband, and also where Fb lies, as that defines the usable low-frequency limit of the design.
I don't think the SS15 can be correctly sim'd in HornResp anyway. It's got two expansions between S3 and S4, according to the PDF of the layout. HornResp allows for only one.
This thread is awesome, just wanted to let you know!
I love how you keep developing more!
Wish I had the time to contribute more, but have to get up tomorrow and built another weltersys 21" keystone sub, lovely monster.
I did some speadsheets for calculating groundcoupling having a tapped horn on a cargo bike, where I could plot in bike box dimensions & height, unfortunately it's hard to use in hornresp as it haven't got enought S-values for all that steps.
I also did my own take on a Tham12, to go deeper & smoothen out the upper end, with more compression like the "Brian" version for the rcf lf12n401 as I had it, I also have the fane 12xb probably more suited for a tapped horn, but didn't try that yet, did you?
For the bike I ended up with a classic single folded tapped horn covering 74-250hz, sims fine, but I think it need some cone correction as the upper end isn't as nice as it sims.
I designed a version of this that is a bit more exponential with a wider mouth and it sims better in the upper & lower end.
The design layouts on here also seems slightly exponential, not conical, is it for the same benefit?
Sorry for rushing in without reading all, couldn't keep my mouth shut, great work guys (as I suppose we're still waiting for the girls?)
I love how you keep developing more!
Wish I had the time to contribute more, but have to get up tomorrow and built another weltersys 21" keystone sub, lovely monster.
I did some speadsheets for calculating groundcoupling having a tapped horn on a cargo bike, where I could plot in bike box dimensions & height, unfortunately it's hard to use in hornresp as it haven't got enought S-values for all that steps.
I also did my own take on a Tham12, to go deeper & smoothen out the upper end, with more compression like the "Brian" version for the rcf lf12n401 as I had it, I also have the fane 12xb probably more suited for a tapped horn, but didn't try that yet, did you?
For the bike I ended up with a classic single folded tapped horn covering 74-250hz, sims fine, but I think it need some cone correction as the upper end isn't as nice as it sims.
I designed a version of this that is a bit more exponential with a wider mouth and it sims better in the upper & lower end.
The design layouts on here also seems slightly exponential, not conical, is it for the same benefit?
Sorry for rushing in without reading all, couldn't keep my mouth shut, great work guys (as I suppose we're still waiting for the girls?)
Hmm.. 100dB passband, but 4 ohms, and those things start dropping off below 60 Hz and are almost 10dB down @ 40 Hz. The low end could probably be brought up a bit with a bit of EQ at Fb, but those ports are bit too small for the response to remain linear at high SPL.
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The designs are probably best described as dual-expansion parabolic 🙂.
And yes, this layout tends to provide a smoother passband and reduce if not eliminate the notch in the FR that can occur around the upper end of the passband.
I experienced the same in hornresp wizard, but possibilities are limited in hornresp, I don't know what you mean by dual expansion parabolic? -a joke? parabolic curves has negative expansion, look at this from bottom up:
https://upload.wikimedia.org/wikipe..._features.svg/450px-Parabola_features.svg.png
https://upload.wikimedia.org/wikipe..._features.svg/450px-Parabola_features.svg.png
So it might be the other two sides of the curve that is inside? (making it expand progressively)
Nope - no joke. Parabolic expansion is the best match for what happens when you 2D fold a horn up into a box (two sides parallel, two sides at an angle, at any point along the expansion). That's why most of the sims here are set to use PAR (for parabolic) expansion.
Yep, I normally eq up a bit below 50. They do "OK" for what I am doing in smaller venues when they aren't pushed. This is why I was thinking I would be happy enough with the SS15, especially considering the low cost and weight.
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They look completely opposite:
Look at you own 2d bottom right:
http://www.diyaudio.com/forums/atta...rse-engineering-sim-tham15ds-20150909-th2.gif
The compare to parabolic:
https://upload.wikimedia.org/wikipe..._features.svg/450px-Parabola_features.svg.png
They are the complete opposite see?
But if you mirror the parabolic curve sides around the y-axis center you get closer to your box in 2d, is this what you mean?
Look at you own 2d bottom right:
http://www.diyaudio.com/forums/atta...rse-engineering-sim-tham15ds-20150909-th2.gif
The compare to parabolic:
https://upload.wikimedia.org/wikipe..._features.svg/450px-Parabola_features.svg.png
They are the complete opposite see?
But if you mirror the parabolic curve sides around the y-axis center you get closer to your box in 2d, is this what you mean?
Yup. In any case, because of the dimensions involved, the parabolic curvature is very slight, and look almost like straight lines in the sim.
... and here we go - 190L in total.
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