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Discussion Starter #1
My friend who's a DJ needs a sub built (in one week) so I'm trying to get something going quickly here.

Need a final load of 4ohms and though he doesn't have an amp yet I think we're going with 500RMS or a little more at 4ohms. This will be for music events that he DJ's so anything below 35-40hz is a non issue. Really, music doesn't have much info down there anyways so we're good as long as I can get a SOLID 40hz out of it. I need efficient, loud and budget....

I'm thinking either a 15" or an 18" in a ported enclosure. Good news is that we're not looking for low end response, just Xmax control.


Ideas? It's kinda a different goal than I'm used to so this is new territory for me.
 

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My friend who's a DJ needs a sub built (in one week)
Thats the question, can you build one in a week along with getting the parts/driver you need. What kind of budget?
 

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Discussion Starter #3
Thats the question, can you build one in a week along with getting the parts/driver you need. What kind of budget?
I can build anything....the drivers will likely be a drop in install once the cabinet is made. He just wants it carpeted so finishing will be a snap. I can build the cabinet while the stuff is in the mail. I'm thinking about running that Bash500watt plate amp that PE has. That's ultra cheap power. For the driver I'm thinking $150.
 

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That Bash amp should do fine particularly because hes only using it for music. I'm Hoping MikeP chimes in soon as he is one of the best guys to ask.
 

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Discussion Starter #5
I'm torn between using a legit subwoofer and a PA driver. He's had his mains playing down all the way but he just needs the low end. He needs 100Hz and below basically.
 

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I do recommend some sort of 30Hz HPF or he may run the risk of over loading the amp. Dont use a PA driver the quality will suffer.
 

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Discussion Starter #7
Also, ported and Tapped Horn are my only options since those will give us the best output. A tapped horn might work REALLY well considering that the tuning frequency could be very high and the box wouldn't be all that bit. That would help cut down on the path length.

One problem though....I've never designed a tapped horn :(
 

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Discussion Starter #8
I do recommend some sort of 30Hz HPF or he may run the risk of over loading the amp. Dont use a PA driver the quality will suffer.
Yeah, i'm wanting to stay away from the PA stuff but I want something with HIGH efficiency; as in 93db+
 

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I was going to suggest the mj-18, but on their website the price has gone up and most of the specs are missing so i'm not sure what is up with that.
 

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Discussion Starter #11
I was going to suggest the mj-18, but on their website the price has gone up and most of the specs are missing so i'm not sure what is up with that.
Nice suggestion. Here are the specs I was able to find on it. Same one?

Power Handling: 600 watts RMS
Sensitivity: 93.4db (2.83 volts)
Impedance: 4 or 8 Ohms (SVC)
Outside Diameter: 46cm (18 1/8")
Mounting Diameter: 41.9cm (16 1/2"")
Depth: 20.3cm (8")
Recommended Box Sizes
Sealed: 80 litres (2.8 cu. ft.)
Ported: 128 litres (4.5 cu. ft.) 30Hz tune
EBS: 250 litres (8.8 cu. ft.) 18Hz tuning

T/S Parameters - MJ-18 - 8/4 Ohm
Fs = 30.4 / 28 Hz
Re = 7.2 / 3.2 Ohms
Qes = 0.39 / 0.34
Qms = 3.41 / 4.99
Qts = 0.35 / 0.31
Mms = 219 / 229 grams
Rms = 12.3 / 8.1 kg/s
Cms = 0.100 / 0.14 mm/N
VAS = 243.8 / 208.4 litres
Sd = 1029.2 cm2
Xmax = 12 mm
Cone Diameter = 36.2 cm
 

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Discussion Starter #12
From the looks of things they have upgraded it a little and it's now the MJ-18M. Specs look good for what I'm wanting. I don't think 30hz would even make this thing breath hard. Looks like $175 evey where I've looked.


PS: I'd be modeling all these choices but I'm at work right now.
 

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I think those are out of stock anyway.

A Behringer EP2500 can usually be found used for about $225 and they have a 30 HPF built in. They are built for commercial use anyway.

With what you are doing... think car audio, which you do know, so it won't be that much of an issue for you, but the $150 driver might be.
 

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This might work... and at 101db sensitivity, you won't need an EP2500. It won't take much power at all to make it thump. This amp might work... or even that BASH amp you mentioned.
 

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Discussion Starter #15
This might work... and at 101db sensitivity, you won't need an EP2500. It won't take much power at all to make it thump. This amp might work... or even that BASH amp you mentioned.
^Yeah I was looking at that sub. REALLY efficient. I think that would do well even off the Bash amp at 250RMS (since it's 8ohms). With efficiency that high I could run lower power and be ok. I'd really like a plate amp I think only so it's simpler for him to bring in and setup. Less to deal with ya know? I'd imagine that thing can get loud off minimal power. I'm having trouble finding TS specs.
 
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