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Old 17th April 2008, 04:25 AM   #11
AJinFLA is offline AJinFLA  United States
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MJ-18

4.5 cu ft ported. A pair should do the trick.

cheers,

AJ
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Old 17th April 2008, 11:39 AM   #12
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Quote:
Originally posted by dangus
How about renting a sub or two first, and seeing how that helps, before committing money and sawdust?
Yes, do this first!

(I think you'll be a bit disappointed in how little effect one $300 cabinet has outdoors.)
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Old 18th April 2008, 11:15 AM   #13
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Default Bandpass Sub

Quote:
Originally posted by mrbobian

I was hoping to stay in the $300 price range as we still have to buy some power for whatever we end up going with.

Our croud ranges from 100 to 200 kids usually. A good night will bring in a few more.

Also, I have looked and though about some pre-built subs like the peveys or something similar, but I was thinking we could get a little better output and better sound with something I built. It would be way cooler to build something too, I love projects that are a bit beyond my skill! Thanks

Mike B.
Hi Mike,

Do you know how to work with WinISD (or other software) to design a 4th order bandpass sub. You can do this or upgrade your current speakers for a better quality system with better lower output (<250Hz), or just go with a standard sub or horn. What are you going to do?
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Old 18th April 2008, 03:12 PM   #14
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Well there is really no way for us to rent sound equipment. There is two minimalistic music shopes about 45min away from me, other than that it is a good 2hour drive to Grand Rapids where I could probably find some decent sound places. There are pros and cons to living in the great white north!

Anyway, I actually just downloaded WinISD the other day and strated playing around with but I'm not really sure what everything meant. I'm sure I could do alot with it if I was given some directin of what to look for. Does that make sense?

Im not sure we are ready to upgrade our mids, that is another huge financial deal and we are very happy with their performance thus far (except for the absence of lows.) Thanks,

Mike B.
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Old 18th April 2008, 03:27 PM   #15
GM is offline GM  United States
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Quote:
Originally posted by mrbobian

Our croud ranges from 100 to 200 kids usually. A good night will bring in a few more.
Hmm, to get an idea of what's required let's look at what JBL recommends as a minimum for the LFE channel in a 200 seat theater mounted in 1.0 pi (1/4) space (wall/floor position)........

One 18" driver with a minimum of ~97 dB/W/m eff. and ~400 W continuous power handling per channel (this implies a 4-8x greater published rating to minimize thermal power compression losses) or for every ~25,000 ft^3 of house volume, whichever is greater.

Due to the need to limit VLF output in multiplex cinemas, subs are tuned to -10 dB/25 Hz/2.0 pi (1/2) space, so your low B bass would be around -6 dB, ergo if you want to be ~flat this low once EQ'd you'll need a second sub+amp for every single sub system required to meet the minimum.

But this assumes a 4641 (or closely coupled multiples), so if using lower efficiency and/or lower continuous power handling drivers, then of course you'll need more drivers, amp power, though with the advent of DIY tapped horns, this appears to be the most cost effective way to go low/loud since driver, amp requirements are somewhat reduced in size/cost: http://www.jblpro.com/pub/cinema/4641.pdf

That said, with rare exception, live event prosound systems don't go low at all, instead pounding your eyeballs flat with powerful mid-bass, mids. According to prosound speaker designer Bill Fitzmaurice, peak SPL demand for rock acts is from 60 to 80 Hz, with requirements at 40 Hz down a full 25dB from that at 60 Hz, so slightly under-damped (ringing) alignments tuned to between 40-55 Hz to maximize the 60-80Hz BW and 'lift up' the efficiency to maintain it through 300Hz to cover kick drums, etc. is the norm for reflex bass systems. This considerably reduces the sub+amp requirements and especially total speaker bulk.

GM
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Old 20th April 2008, 02:20 AM   #16
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Seems like you really know your stuff. But I don't. So what does all of this mean?
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Old 20th April 2008, 03:23 AM   #17
DaveCan is offline DaveCan  Canada
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Read up and follow the link to the Labhorn plan and forums, the Labhorn cabs are highly regarded...... http://www.partsexpress.com/pe/pshow...0&ctab=10#Tabs
Dave
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Old 20th April 2008, 06:50 AM   #18
GM is offline GM  United States
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Quote:
Originally posted by mrbobian
Seems like you really know your stuff. But I don't. So what does all of this mean?
As Tosh implied and JBL's recommendations confirm, you barely have the budget to throw an adequate amount of mid-bass into a 200+ strong crowd outdoors, much less deep bass, so buy or clone as best you can as many prosound ducted port cabs as you can afford if you want to keep it simple, otherwise you'll have to build more woodwork intensive horns loaded with prosound drivers.

GM
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Old 20th April 2008, 08:21 AM   #19
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Yup, I agree. Find some boxes that will kick out the 60-80Hz range, unless you have tons of money there is no use whatever in trying to get below that. Have a look at Rog's site for some typical boxes.
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Old 6th May 2008, 02:58 AM   #20
hifiger is offline hifiger  Canada
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Personally, i would build one or two 18" cabs, tuned to 40-50 hz, and with focus on cheaper but still sensitive drivers. or buy some of the same (peaveys). Down to 40 hz is often just bass guitar, and you really can still reproduce bass guitar with 50 hz extension as a lot of people aren't used to hearing a strong fundamental of a bass guitar, 50 Hz is so low, that most people perceive it as "deep" bass.
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