Question for Cab Theory Guys - Considering Schoeder Mod

bucephylus · #1 04-09-2011, 07:01 PM

For the Cab theory guys:

I have a pair of the Schroeder 1212BMF cabs. They sound excellent except that they are shy at the low end. This has been discussed already for these cabs, nothing new.

Thinking about some options, I was considering replacing the Celestion drivers with Eminence 3012HO's. But, I am also aware that cabs are tuned for particular drivers. No doubt, I would need to bounce this off Jorg; just wondering if this is so off the wall it is not worth considering. Any input?

Thanks!

will33 · #2 04-09-2011, 07:25 PM

If that's one of the cabs with angled speakers, that angle eats into a lot of internal volume inside the cab. Some drivers will model better than others but I doubt there's enough space in there to get much of an increase below say 80hz, just guessing.

dBPete · #3 04-09-2011, 07:29 PM

I've had no success trying drivers in cabs that weren't built to spec for them. Usually issues with undesired rolloff.

::::BASSIST:::: · #4 04-09-2011, 07:39 PM

Quote:

Originally Posted by will33

If that's one of the cabs with angled speakers, that angle eats into a lot of internal volume inside the cab. Some drivers will model better than others but I doubt there's enough space in there to get much of an increase below say 80hz, just guessing.

BMF cabs are front firing.

bucephylus · #5 04-09-2011, 07:43 PM

Quote:

Originally Posted by dBPete

I've had no success trying drivers in cabs that weren't built to spec for them. Usually issues with undesired rolloff.

No, I realize this is a long shot question. Just figured I'd ask.

bucephylus · #6 04-09-2011, 07:46 PM

Quote:

Originally Posted by will33

If that's one of the cabs with angled speakers, that angle eats into a lot of internal volume inside the cab. Some drivers will model better than others but I doubt there's enough space in there to get much of an increase below say 80hz, just guessing.

A bit off topic, but I do not personally think that the low end shyness Schro's are known for is entirely due to that angled cab design. Jorg pretty much borrowed that from some designs used by Tech Soundsystems (now Tecamp). I have two of the early Tech cabs, and they are not low end shy at all, to say the least.

Back to the question at hand...

will33 · #7 04-09-2011, 08:08 PM

Quote:

Originally Posted by ::::BASSIST::::

BMF cabs are front firing.

Well, that takes that theory out of the running. Next step is to measure how much room you have to work with and start modeling stuff.

craig.p · #8 04-09-2011, 08:11 PM

Trying to get a handle on that porting from the pic on their web site. Are there port tubes in that cab or did they simply cut five pieces out of the baffle board?

Measure the box's internal dimensions, and measure the port dimensions. If the ports are only baffle cutouts, then the port length will be the thickness of the baffle board. Also try to estimate how much volume the tweeter and cab bracing are occupying. That's where you need to start.

craig.p · #9 04-09-2011, 08:11 PM

Whoops, Will beat me to it.

will33 · #10 04-09-2011, 08:12 PM

Quote:

Originally Posted by bucephylus

A bit off topic, but I do not personally think that the low end shyness Schro's are known for is entirely due to that angled cab design. Jorg pretty much borrowed that from some designs used by Tech Soundsystems (now Tecamp). I have two of the early Tech cabs, and they are not low end shy at all, to say the least.

Back to the question at hand...

The Tech stuff then likely had enough room for the speakers they used to get lows. The angle kinda naturally filters out upper mids and highs from those speakers, sort of like building a lowmid response bump into the cab.

MuzikMan · #11 04-09-2011, 08:13 PM

From a scientific standpoint this could be interesting but from a practical standpoint it is not a good idea. If your cabs are working properly you should probably sell them and buy cabs that sound better to you. Your proposition would cause you to lose money. With that said, the Eminence 3012 HO driver do work well in smaller enclosures so there might be something to it. Why don't you post your cab's internal dimensions and port dimensions so we can get started?

bucephylus · #12 04-09-2011, 08:49 PM

Thanks.

Cab is 17 x 28 x 15. Inner dimensions are probably about 1" less. I'll have to go have a look at the ports. I'm not all that familiar with them.

Understand about the economics; but, I'm not likely to recoup my original cost, so the the extra $ for the drivers might be an even trade to going to different cabs. Plus, there aren't any other 2x12's that are this compact. I'd prefer to make these work.

bucephylus · #13 04-09-2011, 08:52 PM

Quote:

Originally Posted by will33

The Tech stuff then likely had enough room for the speakers they used to get lows. The angle kinda naturally filters out upper mids and highs from those speakers, sort of like building a lowmid response bump into the cab.

You would need to hear the original Tech Compact designs. They gave up very little. Gary Grainger and Kim Stone both gigged them to death.

bucephylus · #14 04-09-2011, 08:56 PM

The ports are simple cutouts in the front baffle. Two 4" triangles on top left and bottom right (= 16 sq") and one round 2 1/4" diameter cutout between the drivers on the right. Don't see anything more complicated going on.

Blues Bass 2 · #15 04-09-2011, 09:04 PM

Even if they would work in that cab the 3012HO's cost about $300 a piece now from Parts Express . Replacing all four would be about $1200 . That's a lot of dough just for a speaker upgrade that may or may not work .

bucephylus · #16 04-09-2011, 09:25 PM

Correct. If it won't work, its off the table.

will33 · #17 04-09-2011, 09:42 PM

Quote:

Originally Posted by bucephylus

Thanks.

Cab is 17 x 28 x 15. Inner dimensions are probably about 1" less. I'll have to go have a look at the ports. I'm not all that familiar with them.

Understand about the economics; but, I'm not likely to recoup my original cost, so the the extra $ for the drivers might be an even trade to going to different cabs. Plus, there aren't any other 2x12's that are this compact. I'd prefer to make these work.

The way the corner hardware looks on it, it may be 1/2" material. The baffle should be recessed about an inch too so say 16x27x13? Which measurement is the depth?

That comes to 3.25 before allowing for drivers, ports and bracing so approximately 3 cu.ft? Doesn't leave much to work with. 3012HO's, yeah. basslites2012's work well in smallish boxes as well and wouldn't be quite as "forward" in the mids and thus sounding a little bassier but you'd then have a 300watt, 4ohm cab and even those are up to $140 each now.

How deep do the ports go into the cab?

bucephylus · #18 04-09-2011, 09:54 PM

Quote:

Originally Posted by will33

The way the corner hardware looks on it, it may be 1/2" material. The baffle should be recessed about an inch too so say 16x27x13? Which measurement is the depth?

Correct. Depth is 15" on the enclosure; probably 13 1/12" interior.

Quote:

Originally Posted by will33

How deep do the ports go into the cab?

Ports are just cutouts in front baffle.

bucephylus · #19 04-09-2011, 09:57 PM

BTW, thanks for all the replies so far. Much appreciated.

will33 · #20 04-09-2011, 09:59 PM

Quote:

Originally Posted by bucephylus

Ports are just cutouts in front baffle.

Haven't figured it all up but that's going to be tuned pretty high. A speaker swap would likely require adding some amount of wood to make them go deeper into the cab.

Is there a bigass capacitor or anything in the cab that would constitute a filter in line with the woofers? I'd be worried about unloading below the tuning frequency if it's that high. Would certainly make a lot of boom.