I have JBL 15s and 18s...want to add more...what do?

djrob

I have a mobile DJ company, I'm looking to get two more speakers.

I have a pair of JBL MP215s (http://www.jblpro.com/mpro/PDF/MP215.pdf) and a pair of JBL MP418S (http://www.sonorizarenunta.ro/MP418S.pdf). I also have a pair of Bose L1s, but I think that's not pertinent to this discussion.

These are both passive speakers.

What I'd like to do, is add two additional speakers to the system for larger events. Do you have any recommendations?

Can I mix in powered speakers (I don't see why not since I'm using a PA+)? What makes the most sense from a mobile DJ perspective?

Thanks!

Gadget

BAD idea to use dissimilar speakers in close proximity.. also bad idea to overlap horn patterns.. and I believe the JBL MP215's are 70X70... which gives a bit more coverage (laterally) then needed... so, MP215's or sell them and get something you CAN find 4 of...

G

djrob

Thanks, Gadget.

Spreading out single 15s probably doesn't make a lot of sense for many of the venues I work...what about a pair of JBL JRX125s? (http://www.jblpro.com/catalog/support/g ... &docid=839)

I could get a pair used for $500.

Is it unwise to add the jbl mpro18s subs with those? (i.e. for smaller gigs either use the pair of jrx125s only?)

OR

I could get a powered pair, PRX 635 (http://www.jblpro.com/catalog/support/g ... docid=1548)

Dennis

Like Gadget says, get 4 of something

djrob

Correct me if I'm wrong, but with 4 of the JBL MP215s (or something else), I need to keep them far enough apart that they don't really overlap on their sound projection...

Perhaps this will help me out...why would a person use a double 15" cabinet as opposed to 4 single 15 cabinets?

Dra

A single horn can keep up with quite a few low/mid drivers.

DRA

Gadget

Look, there isn't a really easy way to look at this... because low frequencies are omnidirectional... as the frequencies get higher and higher they begin to get more and more directional...until they are laser beam like in nature. The horns, which are more efficient and generally require FAR less power are the devices that disseminate the most of these frequencies...

Hi frequencies are by nature more related to clarity and detail and so when they are messed up or missing.. it is VERY OBVIOUS. As the horn patterns overlap there are frequencies that arrive at your ear anywhere from slightly out of phase to 90 degrees out of phase will become more and more inaudible until they are TOTALLY erased... thats right GONE... as you move through the field of a pair of near proximity horns that are overlapping in coverage you will hear phasing.. cancellations.. and all manor of sonic chaos

So, the lower frequencies are interacting as well, but are NOT as audible as the high frequencies... and thus not as critical to the "message". When 2 drivers of the same make and the same size/make are placed within a certain number of wavelengths (usually one or a very small number) they couple and are additive to the point of 3dB of additional output... however... the lowest frequencies will cause some problems so the second woofer is hipassed.. like the Peavey SP4 which is considered a ~quasi 3 way speaker, even though they have 2 identical BW 15 speakers. It's generally accepted that if your going to put 2 horn loaded speakers together to cover the same area, or have big groups of trap boxes, that you would stack the speakers with the horns together... the next row up would be woofers together and horns up.. next row... horns down.. so they are together, and so on...

That it where line arrays come into play, horns together with only a few degrees of vertical coverage so as to not have horn interaction ...

As I mentioned above, dissimilar speakers placed side by side can REALLY step up the interaction.. and is generally considered to be a BAD deal...

The JRX 125's are a budget speaker with poor characteristics and a 90x50 pattern... these are a 1 per side speaker ... and a budget solution at best...

Gadget