Feedback Forum - Tight Packin' stacks

Tight Packin' stacks

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URL: https://forum.speakerplans.com/forum_posts.asp?TID=92648
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Topic: Tight Packin' stacks

Posted By: jmorken
Subject: Tight Packin' stacks
Date Posted: 10 July 2015 at 6:02am

Project Objectives:

Ground stack system - 2 stacks minimum, 1 per side for rock-n-roll, combined for dance.
Fit in my pickup truck (under the truck cap) - 47"w / 70"d / 39"h between the wells.
Usage - small rock and dance shows, 100-200 people.
Modular - separate tops and mid-bass for easy setup and flexibility

About Myself:

I'm new here so I thought I should introduce myself. I've been doing production professionally for ten years: first for a production company, now as a technical director. Building speakers has been a hobby and passion of mine since high school. My most well documented project would be

http://www.diyaudio.com/forums/multi-way/195955-unity-horn-budget-drivers-active-x-over

- here, though I've built everything from little boom boxes to a pretty massive bass horn. This system is mostly for my own fun. It'll be used for gigs for my band, as well as private parties and events.

Project Overview:

Tops: I got the tops recently from a decommissioned installation and that was the impetus for this project. I've got four JBL AM4200/64 boxes
http://https://www.google.com/?sa=t&rct=j&q=&e=s&source=web&cd=1&cad=rja&uact=8&ved=0CB8QFjAA&=http%3A%2F%2Fwww.jblpro.com%2FProductAttachments%2FAM4200_64%2520.pdf&ei=9EKfVcq-FIP8-AHqi6WIBQ&usg=AFQjCNGvegHBulMe0pf7N8Oq2EBSPw9FKA&sig2=ohs_QYCfoG5i1wkbNGct2A&bvm=bv.96952980,d.cWw The cabinets are massively oversized for the horns, so I'll be ditching those and building smaller ones. They need to be crossed at 400.
Mid-bass: Dayton http://https://www.parts-express.com/dayton-audio-pa310-8-12-pro-woofer--295-032 - PA310-8 in a ported offset horn. I'm thinking 2-high per stack gives me a very nice bandpass response from 100-400 or so.
Subs: http://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers. - Keystones by Art Welter. These seem to fit the bill: solid to 40hz (can be tuned lower by covering the mouth), work well in singles, efficient, and fit well in the truck.

The general Idea:

Close up of the Kick bin:

Horn Resp Sim for the Midbass:

One and Two Cabs at Max output:

All the possibilities:

So, I wanted to share all this because I have some apprehensions about the plan and wanted to run some questions by you folks with a lot more experience in this field.

How does the Hornresp sim look?
Any subjective opinions on this style of ported horn? I'm a little worried about the high Q alignment and respective group delay. The efficiency is pretty terrific though. Would I be happier with a lower tuning or maybe just a direct radiator 15"?
System balance? I've got the two midbass matched pretty well to one top for average output (127db). One sub will do 130db. I'm wondering if I would be happier scaling back the tops to make room for more subs. Thoughts?

Thanks everyone for the great community! I'm hoping I can contribute something worthwhile.

Edit: I can't get the damn hyperlinks to work.

Replies:

Posted By: djkrusada
Date Posted: 10 July 2015 at 1:16pm

I cant help with your questions but two thumbs up for a really nice modular design :) bump!

Posted By: Meat
Date Posted: 12 July 2015 at 10:44am

Looks very nice. The constant directivity plot from Hornresp might be useful to look at the predicted dispersion although with that kind of design I'm not sure how accurate it'd be. Also, it seems that the upper extension of the mid horn isn't that extended so it gives you little room for manoeuvre to fiddle with crossover frequencies.

I'd probably want a 15" reflex to do the same job but then again that's a bit boring!

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Don't test the champignon sound

Posted By: Dutchman
Date Posted: 30 October 2015 at 8:45pm

Very nice!!

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We need more SPL!

Posted By: 4AC
Date Posted: 13 March 2018 at 11:00am

So what's up with this project?

I like the tight-packing idea :D

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