Building my own frfr cab, maybe

R

rknrollo

Member
So I scored an empty crate 4x12 cab today on craigs for 25.00, Basically for backline just to stick my pair of behringer b212d speakers inside of as well as FOH, Then I decided to take apart the behringer speakers and to my surprise the 550 watt class d amps,crossover, eq,level and jacks are all housed in a neat little box, it got me thinking why not just gut them and install the drivers and mount the amps/panels neatly to the back, my only problem is where to get some type of a horn to disperse the HF driver? Can I make them from wood? I know I will have to make some proper baffling as well, The behringers actually sound very good for the 200.00 each I paid, I figure in a birch plywood cab they may sound better. I am planning on buying some higher end frfr speakers anyways so I thought what the heck just for fun and on the cheap. 102_0043.jpg102_0044.jpg

I dont plan on using it except for larger gigs or when I want a stack behind me, I have to remove the "crate" Logo and make my own "FAS" logo to go on the front.
 
I love Frankenstein mod's like this. Keep us updated and share pics of the process and the result.
 
If is looks you are looking for then why not just make a new baffle or cut a rectangle on the one you have and just put the speakers behind it just the way the picture is.
 
the handles will have to be cut to fit both inside and I could have one unit with wheels with everything in it.
 
well I got the 12" waveguides to screw the HF drivers into today and completely disassembled one of my B212D speakers, looks like everything will work as planned, I am shooting pics and video of my "frankenstein" project as I do it, I am going to install one side first and A/B them to the original B212D speakers, from what I can tell by weight the whole stereo dual 550 watt (Looking)4x12 cabinet will weigh much less than a standard 4x12 cab, I am no sound engineer but I think when this is done it will sound awesome, 25.00 cabinet, 400.00 for 2 behringer B212D's, 30.00 for two 12" tweeter waveguides, a bit of plywood I have sitting around, some dynomat I have sitting around and a bit of studio foam I have sitting around, we will see................
 
I'd suggest wiring the AC receptacle on the power modules together internally if possible, to allow for one cable to power both. You may need to play with the internal volume of the box, though if the 4x12 remains sealed it may not be an issue. The Behringer cabs are probably ported. You can use styrofoam blocks to decrease the chamber size.
 
decidied to do one side of the cab over the weekend and A/B the cab vs powered speaker, sounds really good but a bit boomy on the bass, the 12" round waveguides for the tweeters are perfect really smooths out the highs over a wider range, question? I have a bunch of acoustic foam left over from my studio, I was thinking of lining the interior of the cab with it to reduce the standing waves thus getting rid of the boominess am I correct in my assumption?
 
Well I put the cab into play tonight, I had some egg crate foam in the garage so played a cd through the one side of the cab and the powered speaker and added foam and polyester batting until I got them almost the same (by my ears) sound then I gutted the other speaker and went to town, still slightly boomy on the bass but way more controllable with the onboard 2 band EQ and great cab in the room feel and did not change a thing on the axe fx, total weight is 74 lbs. I am going to experiment with boxing the woofers in and using some different damping material also need to add some mass to the back side of the 12" plastic waveguides on the HF drivers. I have pretty much acomplished what I set out to do, build a 4x12 looking cab that sounds as good or better than my active speakers that I was using, so far 400 bucks for 2 behringer B212D active speakers, 25 bucks for an empty crate cab, 30 bucks for two 12" waveguides, 15 bucks for some plywood, 5 bucks for some polyester batting, egg crate foam left over from my RV, some spray glue I had, some screws I had and about two hours of my time, I'm no sound engineer (I'm a plumber by day) I have no test equipment but my ears. I will test the cab at practice This Thursday. 102_0096.jpg102_0098.jpg
 
I have used the cab twice so far, surprisingly it sounds great! When I play it loud no one knows it is a stereo PA in a cab, the 12" round waveguides around the tweeters are the hot ticket real even, wide and smooth dispersion. I have made no changes to the patch settings on the axe, basically I can fine tune it with the built in 2 band eq, I find that I can now use more high end without being harsh and more low end without being boomey as before in the Behringer plastic boxes.

Over the weekend I got my pair of EV ELX 112p active speakers, although I did not try them in a "Band" setting or high volume but side by side just A-B ing them I think my cab sounds better. I am going to experiment with some different damping material, add some mass to the backs of the plastic wave guides and possibly experiment with boxing in the woofers. I have read you cant just stick full range speakers in a guitar cab and get a good result, yes you can. Heres a couple more pics102_0097.jpg102_0067.jpg102_0060.jpg102_0095.jpg
 
used my home made cab tonight, opened up for Michael Schenker and the sound was incredible, before the show earlier in the day I went back and forth with my cab and my EV ELX 112p's and hands down my homemade cab sounds way better and louder for some reason, my cab has behringer 550 watt amps, my EV's have 1000 watt amps my cab is louder, I dont get it. Michael Schenker actually told me he liked my sound tonight and his tone is incredible.
 
Wow, that turned out really nice! One other thing you might look at if it's possible is to front load the speakers and lenses on the baffle, it might give you a bit more side coverage. I know it a lot more work but the results could be worth it.

It would be interesting to see what the response of the cab is.
 
I didn't want to rip off the grill cloth and originally planned to do it that way, basically just an experiment because I knew I was getting the elx 112p's, how would I go about measuring the response? I have seen some free frequency anylizer software out there, all I know is my ears and after 30ish years of playing and recording and engineering other bands it sounds really good, I do use the eq on the back of the amps, cut the low end about -3 and and about 7.5 on the high I had to do that when they were in their original enclosures low end about the same but not as much high, so not truly flat, I am guessing because of switching to round 12" wave guides on the tweeters vs rectangular what ever they were smoothed out the high end. I can say where ever I stand the cab projects just like a regular guitar cab, the high freq's are consistant wherever you stand.
 
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