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help with pa speaker build?

B

Billhead

New Member
I have a pair of EVM 15L series II drivers,

http://www.bassreflex.de/index/ev/ev.htm

and I would like to build some basic pa cabs. I just can't seem to make heads or tails of the information I am finding on the web. I am a carpenter not a technician. Was wondering if anyone would care to use some of their knowledge and give me some laymens term ideas on what to use for highs? what kind of cabinet to build, what crossover I might use ( I wouldn't mind trying my hand at building the crossovers, I can solder a bit!) Or if in reality I am just plain wasting my time and I should S#!t can the whole idea.

Sorry if I was supposed to post in the DIY section, I just thought musician types might have a firmer grasp on what it is I am trying to do, use up some old drivers, build something new and hopefully end up with a serviceable pair of pa speakers and not go broke doing it.

By the way the band plays older rock, blues and my favorite :banana: boogie woogie! (sorry I had to use the bannana)

Look forward to any ideas...

Thanks,
Billhead
 
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Sounds like a fun project ahead!Not sure about what budget you wanna stick with,so I can only point in a direction I've been.If you do a search on the specs of the cabs and links mentioned,ya got an idea already.EV makes a good driver for about $130 + horn +crossover.For recorded music my ears like the EV CD horn like the model S-152 uses.I have them,and a pair of SH-1512ER's.(wider dispersion for live music crowd coverage)Parts Express has Eminence drivers and horns,Radian,JBL,and Peavey,plus imports I know nothing about.
I wouldn't try to push them hard below about 55-60hz without a sub.I'd keep the bass guitar and the kick out of them without a sub,too.I use a decent EQ and a comp/limiter.(well,10 channel's worth altogether-keeps the feedback down and protects the whole speaker system,and everyones ears,too)For the money,the Eminence top end looks pretty decent.I wouldn't be afraid to try a cheaper horn,either.If ya don't like it,use 'em in garage speakers!But I'd use good drivers and Xovers,just 'cause at 1 am,failure is NOT an option when your audience has alcohol!!! Terry
 
I have built a LOT of PA and MI gear over the years.

The Eminence H290 horn lens (or "flare) with Eminence PSD2002 is excellent.

Your EV woofers have very high efficiency. The Peavey RX22 horn drivers are also very good, and might be even better with these woofers.

If you can find for me, Qes, Qms, I'll get cabinet size and port for you. I will also need Le (voice coil inductiance) and Re (voice coil resistance) to work out the crossover.

For basic cab construction tecniques see:

http://colomar.com/Shavano/pa_page.html

http://colomar.com/Shavano/pa_speaker_project.html

I like to round off the edges with a router before covering with carpet. You can get Ozite carpet in 2' x 8' rolls in the automotive section of Walmart. Adhere with 3M77 spray on contact cement. Cab hardware (plastic corners, terminals, etc,) Partsexpress.com.
 
Thanks guys for the info, I'm short on time right now, but later this evening I'll sit down for some reading. As far as budget...well...depends what I can come up with, the $23 in my pocket... Oh wait, I found another .63 in my front pocket! I'm gonna try to figure out the cabinets for right now, I have access to lots of wood for free! So I guess my first priority is figuring out which horns I'm gonna use and cab dimensions so I can get that under way. And I'll start the scrounge for monies for the parts as I'm going. Here are links to specs I found...
Pg1
http://forums.klipsch.com/forums/storage/6/738387/EVM15L Spec Sheet 1.jpg
Pg 2
http://forums.klipsch.com/forums/storage/6/738393/EVM15L%20Spec%20Sheet%202.jpg

Thanks again and I'll get back later


Billhead
 
Billhead said:
Thanks guys for the info, I'm short on time right now, but later this evening I'll sit down for some reading. As far as budget...well...depends what I can come up with, the $23 in my pocket... Oh wait, I found another .63 in my front pocket! I'm gonna try to figure out the cabinets for right now, I have access to lots of wood for free! So I guess my first priority is figuring out which horns I'm gonna use and cab dimensions so I can get that under way. And I'll start the scrounge for monies for the parts as I'm going. Here are links to specs I found...
Pg1
http://forums.klipsch.com/forums/storage/6/738387/EVM15L Spec Sheet 1.jpg
Pg 2
http://forums.klipsch.com/forums/storage/6/738393/EVM15L%20Spec%20Sheet%202.jpg

Thanks again and I'll get back later

Billhead
Click to expand...

Bill, these woofers need a good horn to keep up with them. The Eminence PSD2002 will work well. Use the Eminence H290 horn. There are cheaper horns available, but they are thin walled and will not support this very heavy horn driver. This horn driver has a magnet bigger than many 12" and 15" woofers. Hitting a bump with the van on the way to a gig might break a ligher horn. This Eminence horn is not only designed especially for this driver, but is very thick, and has a lot of reinforcement around the mounting flange.

So, if you will plan on using these with your woofers let me know and I'll draw up a cabinet, port, and crossover for you.
 
Bill, here they are in the Driver Database

http://www.thielesmall.com/database.asp#

Enter 15", Electrovoice, Woofer, PA, and click Go. Click on your woofer.

There is enough there to design a good crossover.


15"

VAS 245 L or 8.66 cft

Qts .238

Qes .25

Qms 4.96

Fs 43 Hz

SPL 101 db

P 200 w

Xmax 3.3mm

Re 5.2 ohms

Le 1.24 mH
 
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OK, Billhead, fs is 43 hz, around and below which you will get distortion. So put this in a practical 5 cubic ft cabinet (actual 5.5 cft, allowing .5 cft for volume taken by braces, woofer, horn). Port tuning 57 hz.

For this just cut two holes each 3.7" dia. in the two lower corners. No tube, the thickness of the panel is good. If you want to make it pretty, you can get two ready made plastic ports 4" dia. and make them 1 1/8" long.

I'll attach a crossover later.
 
I tried to attach a Boxplot of the low end. Not too bad for PA! It's about -1db to -2db down to about f3 = 56 hz. And the box is not too big. You could get lower, but only with a much larger box (8 cft for f3 = 45hz) that YOU have to move in and out of the truck for gigs, if you can even fit it in.

Sealed is just not an option, must be ported for this woofer.

Black trace is the response.

Red trace is maximum output as limited by the power limits of the woofer.

Green trace is power limit. The drop in the low end is due to the cone travel limitations of power vs freq. So, don't expect them to be subs that drive at full power. Use a low cut filter if possible.
 

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Here's a crossover from Wayne Parham of Pi Speakers designed for use with the Eminence PSD2002 horn driver and H290 horn lens ("flare"). This is a sophisticated crossover, 12 db/oct plus zobel for the woofer, and 18 db/oct with padding and top end compensation for the tweeter/horn.

For your use (10 db cut):

R1 = 16 ohms
R2 = 16 ohms
C1 = .47 uf

For your woofer (calculated from specs in the driver database), the Zobel is

R3 = 8 ohms
C5 = 30 uf

Parts List from Parts Express

R1 16 ohms 10 w non inductive 004-16
R2 16 ohms 10 w non inductive 004-16
R3 8 ohms 20 w 017-8
C1 .47 uf 250v poly 027-406
C2 8.2 uf 250 v poly 027-426 (close enough to 8.0)
C3 22 uf 400 v Jansen film 027-940
C4 10 uf 250v poly 027-428
C5 30 uf 250v poly 027-440
L1 .6 mH 20 ga 255-040
L2 1.0 mH 250w 266-550
 

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WOW paul, you've been busy!

I just went through parts express and lined up the order, came out to about $330.00 W/shipping. It's gonna take me a while to scrounge funds. I am going to start the hunt for plywood and get going on the cabinets. We have large pieces of 3/4" 10 ply birch plywood left over all the time. That should work nicely for the cabinets.

I am going to use the 4" port tubes, will look much nicer.

As far as the crossovers, I might just take you up on your offer...I guess I have a bit before I decide.

I will get back and post pictures when I get the cabs started.



Thanks again paul for all your help.

Billhead
 
We have large pieces of 3/4" 10 ply birch plywood left over all the time. That should work nicely for the cabinets.

I'd be building a LOT of speakers... and divorced.

Remember, when you build musical inst speakers, make the box 2" deeper than calculated for the require volume. Then set the baffle back 2" into it so there is a nice protective lip. This gives protection to the woofer, woofer grill, and horn.

I would round all edges with a router (1/4" - 3/8" radius) and paint with truck bed liner. That is the quickest and easiest, toughest coating these days. Better than carpet in that it is easy and fast to apply, easy to repair. Also, you can easily wipe clean with a damp cloth.

Don't forget to put steel "top hats" in the bottom for mounting on speaker stands. PE has some excellent stands, a pair in a carry bag, for $30. They are under the Dayton label at Parts Express. I like these because they have holes in the telescoping pole and there is a safety pin to put in there to keep it from accidently collapsing. Also, the legs have a LOT of spread for a nice stable base. They have a 1 3/8" pole, so you need a 1 3/8" steel top hat. (NEVER plastic for a top hat).

Decide if you are going to use 1/4" or Speakon jacks. You can get terminal plates for both. You can even mount a Speakon jack AND 1/4". I advise always using two parallel 1/4" jacks ("in/out") so you can jumper to other speakers.

You can get a set of 16 plastic chevron stacking corners for about $4, enough for a pair of speakers, from PE.

And a 15" waffle grill and mounting lugs. You need 8 ea 1/4"-20 screws and T-nuts for mounting the woofer.

Anytime, Billhead!
 
As far as X-overs go, I'd skip the 'passive' ones completely and go with 2 amplifiers...a BIG one for bass, and a very modest one for horns, and use an electronic x-over. You'll have better sound and TONS more headroom, efficiency and volume up front. Your amps will be loafing at room volume instead of working their butts off. You'll have more money for amps and horns...an electronic x-over can be had for around 100 bucks, new.

Also, run in mono. You want those woofers working in unison, which will give you tighter bass presentation and that "THUMP" on the kick drum that gets the ladies dancing. No one in a bar or club gives a rat's petuti about stereo imaging. And most amps have a 'run in mono' mode that couples both channels together, in effect doubling your power. If the speakers in question are 8 ohm speaks, then running a pair of them in mono will drive your amp at 4 ohms, giving you even more bang for your buck.

This isn't about high fidelity, this is about playing gigs in bars and 'sounding good', right? :)

Feel free to PM me for some recommendations on good PA amps and Electronic X-overs on the cheap, I've been at the live sound thing for quite a while.
 
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