SW under a dj booth

I'm building a home studio with a dj booth. the room dimensions are 32 feet by 12 feet. the ceiling is 9 feet high.

i want to construct a subwoofer under the dj booth. the booth dimensions are 12 feet wide (the width of the room) & 6-7 feet deep. it can only be elevated 2-2 1/2 feet off the ground otherwise i'll be scraping the ceiling with my head. we're talking about 150 cubic feet of space.

first question is how do i avoid reverberation issues & secondly can i use the whole space to construct a horn loaded enclosure. i want to build a bertha unit, the old richard long design but can't find any plans on them. someone told me the bertha was based on the old jensen imperial design but in the jensen the drivers are mounted externally.

is this concept possible or am i just wasting my time.

also can i use jbl double bottoms as subs by reversing the driver to face inward? if so do i need to cover the back of the driver? thanks for any help on this.
 
Re: Re: SW under a dj booth

jneutron said:
Scratch or no-scratch?

Vinyl or cd or mp3?

Sources suspended from ceiling, or active/passive source stabilization?

Cheers, John


hanks for the quick response. i'll be using vinyl & cd. tt's & cdplayers will probably be suspened but not from ceiling. thought about cinder blocks too. what do you mean by active/passive source stabilization? i can also isolate the floor of the booth from the top of the speaker enclosure.

any insight into my other questions? thanks.
 
Re: Re: Re: SW under a dj booth

Andrew S said:
hanks for the quick response. i'll be using vinyl & cd. tt's & cdplayers will probably be suspened but not from ceiling. thought about cinder blocks too. what do you mean by active/passive source stabilization? i can also isolate the floor of the booth from the top of the speaker enclosure.

any insight into my other questions? thanks.

Passive source stabilization: putting a 16 by 16 inch 1 inch thick slab of slate over a three inch thick slab of foam. (it doesn't work on the second floor of a nightclub when the dancers jump up and down..like during "Rock Lobster" by the B-52's..)
Or an inner tube.

For passive, you have to set the resonance frequency of the structure to below the lowest freq you wish to attenuate. gross floor movement, like my example above, requires exceedingly long time constants and low frequency resonance, hence my question about scratching..in forcing the vinyl back and forth, a very low resonance structure will go through large excursions..not pretty..or useable...you'd hafta set tracking way over 5 grams..record life would be very limited.

Active: supporting a surface via active electronics pushing magnetic actuators..seen nowadays in some cars, from what I recall. Choices are: pushing against a reference surface, or pushing against a reaction mass..depending on the forces required and the available travel for the mass, the low freq performance can be determined. But, not a system that is easily built.

Cd's are just a tad more difficult to force "feedback" into, I have done that with a 10 inch reel to reel though.

Cheers, John
 
Andrew S said:
I'm building a home studio with a dj booth. the room dimensions are 32 feet by 12 feet. the ceiling is 9 feet high.

i want to construct a subwoofer under the dj booth. the booth dimensions are 12 feet wide (the width of the room) & 6-7 feet deep. it can only be elevated 2-2 1/2 feet off the ground otherwise i'll be scraping the ceiling with my head. we're talking about 150 cubic feet of space.

first question is how do i avoid reverberation issues & secondly can i use the whole space to construct a horn loaded enclosure. i want to build a bertha unit, the old richard long design but can't find any plans on them. someone told me the bertha was based on the old jensen imperial design but in the jensen the drivers are mounted externally.

is this concept possible or am i just wasting my time.

also can i use jbl double bottoms as subs by reversing the driver to face inward? if so do i need to cover the back of the driver? thanks for any help on this.


Yes you could put a horn in there.
What can you afford driver wise?
Can you use wood?
Do you require 130dB at 32hz?
etc etc.

You could either
a) get one designed specifically for this purpose
b) find one already,which fits the bill(tricky as many are for prosound)Eg WSX horn/SL36 do loud kick but not 32hz.


http://www.geocities.com/xobt/index2.html
 
Wow those are some sick looking horns!!! Those are a bit much. I need to build an enclosure that's max. 22 inches in height. The depth could be as much as 6 feet & the width about 12 feet.

Driver wise I was looking at Eminence. Yes I can use wood. 130 db at 32hz sounds about right. :D

I was told that 4 Emerald" WALDORF HORNS would do the trick. I actually started a new thread searching for the plans. Thanks again for the help.
 

synergy

Member
2004-01-13 12:23 pm
here
dead easy, tried and trusted method for your decks (installed it into a local club with previously unlistenable levels of feedback!)

get some 4" soil pipe and cut it into 1.5" sections and wrap a load of thick rubber bands across it forming something akin to a drum skin

place one under each foot and hey presto no feedback at all (we've even put a deck directly on top of an 18" scoop with 1Kw through it with no problems!)

you might even try building a board with feet to place your cd's on

with a bit of practice scratching isn't a problem either you can practically shake the decks without the needle jumping so if you find they do you're just being too ham fisted!
 
Nice horns. however they look exactly like the old FH1 peavey folded horns. much love though for the peavey look. as for an under booth sub @ the last nightclub we cleaned out we pulled a pair of 115hd's single driver subs. last week with 2 of them driven by a 4C we did a football field concert, at which you could feel the bass at 50 yards in open space


the overall dimensions are roughly 36w * 48h * 21d