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Need a sub for a friend who's a DJ

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7K views 51 replies 10 participants last post by  StereoClarity 
#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.
 
#2 ·
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?
 
#3 ·
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.
 
#4 ·
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.
 
#6 ·
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.
 
#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 :(
 
#11 ·
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
 
#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.
 
#13 ·
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.
 
#15 ·
^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.
 
#23 ·
Ok, here's the deal. Pyle has lost my business since none of those bone heads find it important enough to respond back to my email concerning the TS specs and I can't find them online.

Elemental Designs doesn't get my vote as a company but I do enjoy some of their products and they are priced to compete as well. I own a 13Ov2 (not currently being used) and it was fantastic. I ran it HARD and it just keeps pounding away. I'm looking at their 16Ov2 sub and I think that might be the sub for the job.

efficient and good Xmax. The site says 21mm but I don't know if that's peak to peak or one way. I think it could be one way judging from the way my 13Ov2 performed. Do any of you know for certain? If it's 21mm one way that would be sick and it would model VERY well and it would be my choice no question. If it's 10.5mm one way that makes things a little different.
http://www.edesignaudio.com/product_info.php?t=2&products_id=36
 
#24 ·
Just saw in the specs that it's 21mm one way. Check my graphs and make sure my plotting is correct. I think I've found a winner. My only problem seems to be two things. 1) No round port of that magnitude will fit in that box. 2) What volume box does unibox give me? Does it give me the volume before port displacement or after? Meaning, if I wanted to know the volume needed to be seen by the sub is that VB in unibox? I was under the impression that VB was the size of the enclosure you stuck the appropriate sized port into.


 
#28 ·
He's doing the whole DJ thing so I think he's got a mixer/crossover at his disposal. Either way, I was thinking this dayton 1000 http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-808

Or the bash 500 http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-752


He and I are going to talk about it this morning. If he's got a crossover at his disposal then I'm not going to worry about getting an amp that has one. If not, he's strictly doing music and I can't think of a single song that has info below 20hz. Should I worry?
 
#36 ·
He and I are going to talk about it this morning. If he's got a crossover at his disposal then I'm not going to worry about getting an amp that has one. If not, he's strictly doing music and I can't think of a single song that has info below 20hz. Should I worry?
excellent question... when designing "music only" enclosures, recommendations and opinions are so very strong to keep tuning to no less than 30Hz, but 35Hz-40Hz even "better"

but yes, if there is SOME, you need to protect your driver...
 
#29 ·
Why not get the 190v2 18" if you are going ED? It's even a little bit more efficient. Tune it near 25hz and it should be do-able in a moderate sized enclosure. Some of the Eminence 18's are budget friendly will wang really hard off of little power. They usually do well tuned to 30-35hz. The Peavey Lo-Rider 18" is good too.

BTW Unibox does not count the ports own volume into Vb.
 
#32 ·
^That Peavy is cool but 5Cubic feet is waaaaay too big. Also, I found out he doesn't have an external crossover so I'm going to stick with the ED sub and run that 500watt bash amp. He won't be able to blow it up on that amp and it will go as low as he wants really. I'll keep you guys updated on the build.
 
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