Subwoofer! - PeachParts Mercedes-Benz Forum

JamesDean · #1 09-30-2010, 12:39 AM

http://imgur.com/a/LNNqE/1

Recently commissioned for my dj business. Still a work in progress, trying to seal the box up better than it currently is, it was built by a cabinet builder, so the speaker details were left to me.

Running a Beyma 18G50 18" driver.

Doesnt sound too bad, except for the non-sealed places...

Eventually will be finished with Duratex speaker paint and have a black foam grill to cover the ports.

cmbdiesel · #2 09-30-2010, 02:32 AM

Why three ports?? What kind of extrusion does the speaker have? Is that why there are so many ports? Is the box really plywood? Seems like awfully resonant cabinet. Think I would really make an effort to isolate the frame of the speaker from the box. Got a picture with the driver in it?

JamesDean · #3 09-30-2010, 02:39 AM

http://www.speakerplans.com/index.php?id=184sub

13 ply birch wood. Ill get more pics tmr.

http://www.usspeaker.com/beyma%2018G50-1.htm

BobK · #4 09-30-2010, 08:34 AM

Bah, 18"? How about a 30inch woofer? Remember these big guys?
http://www.pa-anlagen.ch/Manuals/Electro_Voice/Speakers/EDS/30W%20EDS.pdf.

Trying to find the specs from later versions in the 70's. As I recall, they kept improving the things and finished up with a bigger, more efficient voice coil.

Biggest speakes on my own system are 15s. Still, if ya want to reproduce those reallllly low notes, ya gotta have big woofers

JamesDean · #5 09-30-2010, 12:46 PM

Quote:

Originally Posted by cmbdiesel

Why three ports?? What kind of extrusion does the speaker have? Is that why there are so many ports? Is the box really plywood? Seems like awfully resonant cabinet. Think I would really make an effort to isolate the frame of the speaker from the box. Got a picture with the driver in it?

Yes it has three ports, the basic design called for it. I found it on that speakerplans.com website linked above.

The box is 13-ply birchwood as all of my speaker cabinets are made of it.

Elaborate on isolating the frame of the speaker from the box..not quite following you.

I'll have it apart today when I get home from work to do some more sealing work on it.

There were some design changes for ease-of-access that have compromised the air seal between the back panels and upper chamber..so I've gotta work on that. I'm also going to switch to a t-nut system for the back panel. Should work MUCH better than the drywall screws..just as long as i dont strip the stupid things out.

loepke72 · #6 09-30-2010, 01:01 PM

Wonder what the T/S parameters are on that 30" EV driver. Can't imagine Xmax being very large, though it really doesn't have to be with such a large cone.

mgburg · #7 09-30-2010, 01:28 PM

Quote:

Originally Posted by JamesDean

... Should work MUCH better than the drywall screws..just as long as i dont strip the stupid things out.

If you strip the wood, just dip a few toothpicks in wood-glue and hammer them into the hole...let it dry overnight, re-drill the hole (pilot-drill) and re-screw. You're good as gold.

JamesDean · #8 09-30-2010, 01:36 PM

thanks for the tip, but I think t-nuts would be the best way to go for this guy. they'll allow me to tighen down real tight. I'll throw some washers on the heads the of the screws and pull that back panel in nice and snug.