Four Ascendant Audio Havoc 15's

[reedal]

Hey guys!

So, I think i mentioned before in my build log that i wanted to do four 15's when i come home from deployment, and i think (not sure, too lazy to check) that i mentioned the Ascendant Audio Havoc as the choice. Four of them, powered by two SoundQubed Q1-3500.1D's. And that's the plan. So i've been tinkering with some different slot port designs and tunings between 28 and 33hz as recommended by AA and some other builds by members on here, and i feel like i finally found the sweet spot for what i am going for. So here it is:

Dimensions are 26H x 48W x 41.5D, Port is 6H x 45W x 34D. Brings me out to 18.43ft^3, with a torres tuning of 27.94. I didn't factor in the window bracing, so that should drop it down in size to about 18, and raise the tuning a smidge, putting me to where i modeled it at in winISD, which is 18 and 28. now for some pictures.

Port velocity

http://i1372.photobucket.com/albums/ag321/reedal931/Port%20velocity_zps9zawcza6.png~original

Excursion

http://i1372.photobucket.com/albums/ag321/reedal931/Cone%20Excursion_zpsmxc5iect.png~original

TFM

http://i1372.photobucket.com/albums/ag321/reedal931/TFM_zpsrhgcu48r.png~original

and how i plan to make it look. Hopefully with some much better cuts than i did with my box for the 12's. I cut a few pieces with my saw at a 15-ish degree angle before i realized it, so stupid. oh well.

http://i1372.photobucket.com/albums/ag321/reedal931/enclosure%20screenshot_zpszovtnroz.png~original

for some reason, no matter what, i can't embed my photobucket pictures when i'm on PC. I do everything the same exact way on mobile and it works just fine, but not PC. So, sorry for the direct links, but SMD keeps telling me i'm "not allowed to use that image extension on this community."

let me know what you guys think, any changes you may recommend, etc. I will make roundovers on the enclosure of course, but my sketchup skills just aint that great..... and i can't figure out how to do it :/

Thanks!

[Triticum Agricolam]

Looks good to me.

[reedal]

Thanks Triticum!

I just did the math for the bracing displacement, and it comes out to .26, bringing the Net volume to 18.18, and Torres tuning to 28.13. I think even after cabin gain and the tahoe's natural peak around 38, it should still be a pretty flat bandwidth.

[Triticum Agricolam]

Yeah I would think so. I wouldn't be surprised if your tuning comes out a little lower than what Torres predicts, which should further flatten out the response.

[reedal]

I remember you mentioning that when you helped me with my enclosure for the two 12's.

So my question with that is, if the Fs of the sub is higher than the enclosure tuning, that just means that the sub won't be performing as optimally as it would if you tuned to Fs? Or does Fs kind of just get tossed out of the window once you put the sub in the enclosure, since it's a free-air measurement?

I bought the Loudspeaker Design Cookbook, thinking it would give me a better understanding of enclosure design, and while it touched up on it, I didn't really get much out of that aspect. I learned a lot about driver's themselves, but there wasn't a whole lot about determining the specs of the enclosure for optimal performance, other than high and low QTS. Do you have any recommendations for other books and literature that put more information on how to match drivers with enclosures? The internet is a fountain, but knowing which to believe and which not is a hard bargain.

[Triticum Agricolam]

There is nothing magical about Fs or its relationship to the tuning frequency Fb. For some drivers and alignments the correct Fb will be below Fs and and for others it will be above Fs. I wouldn't worry about it too much.

[ShadeTreeMechanic]

The 3db down point on the bottom roll off is calculated directly from Fs. It is possible to end up with tuning below the -3db point. If done correctly it can give a "flat" curve.

[reedal]

Thank you.

One more question for the knowledge bank.. when I was trying to work out the volume and tuning, obviously the lower I tuned the flatter the response got, but the smaller the enclosure was the peakier it got, which I thought was odd, since a larger enclosure should be peakier around tuning, but the peak disappeared as volume went up.

any thought's on that?