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Acme B4 woes.....keep it, replace it, or add to it

g4string

g4string

Gold Supporting Member
Sep 19, 2002
4,069
2,585
49
Melissa, TX
#1
I think I blew a driver (maybe two or three) last night. I am positive that bridging the CA9 is what lead to this......from now on I will run it non-bridged. Now, I have a distorted sound coming from what I thought was the mid-driver or possibly the tweeter. To my surprise, I pulled the grill off the cab and three out of the four drivers are slightly creased, some are worse than the others. I disconnected the bulb tweeter circuit and totally removed the mid-driver. At this point, I am 90% certain I have some speaker damage. This has happened once before with a DB728. I spent about $300 to replace all of the drivers. I really do not feel like spending that kind of cash again, although at this point I have to. I, at a minimum, need to get the cab operational. The problem I am having is that I really dig the sound of this cab. Nothing compares to the massive-tight bottom end of this cab, nothing!!!! But, I pay the price for the tone in efficiency:bawl: However, money doesn't go on trees and I can not afford to replace drivers all of the time, so......This leads me to my question........

Should I ditch the B4 and move on to something with a more efficient design, like maybe a Dr. Bass or Accugroove cab -or- get another B2 or B4 for more volume. Maybe adding another cab will help keep my fingers off the gain knob:smug:

What do you guys think???
 
#2
You have a cab rated at 700W RMS. Bridge into 8Ω your amp gives 1800W, into 4Ω 2000W. What ever impedance your cab is you are giving it close to three times its rated power. I own four B2s but I have only ever needed two to gig with. I cannot imagine needing more than that. I have available 350W for each of the cabinets, 700W total availability. I don't bridge and I have never needed more indoors or out.

First you need to replace the four drivers in the B4. Keep or sell the cabinet has to work. In order to get the level that you think you need you have to get a second cabinet. That much is obvious if you are blowing speakers all the time. I think a second B4 should do the job. If you like the Acme sound then nothing else will do. Does the Crest have a high pass filter? if so is it engaged? Are you using effects? Piezos on the bass?

Paul
 
#5
I've used a bridged CA-9 into an Epifani UL410 in the past. I didn't have one problem putting that kind of power to the cab. I think there may be something else in play here that is causing your speakers to blow. I'm curious if there is an issue with your gain structure that is causing the signal to clip, which in turn with that kind of power would cause your speakers to blow.
 
#6
Tony G said:
I've used a bridged CA-9 into an Epifani UL410 in the past. I didn't have one problem putting that kind of power to the cab. I think there may be something else in play here that is causing your speakers to blow. I'm curious if there is an issue with your gain structure that is causing the signal to clip, which in turn with that kind of power would cause your speakers to blow.
Click to expand...


I agree, I think it was a gain structure deal.......I had the CA9 at about 60% or in the 2-o-clock position and the Demeter, I can't recall.....my bass was at 80% (Lakland 55-94). I would see the red clip light flicker on the CA9 off and on through out the night. Keep in mind this is a loud band. How should I set the gain on the Demeter and CA9 to prevent this again??
 
#7
g4string said:
I agree, I think it was a gain structure deal.......I had the CA9 at about 60% or in the 2-o-clock position and the Demeter, I can't recall.....my bass was at 80% (Lakland 55-94). I would see the red clip light flicker on the CA9 off and on through out the night. Keep in mind this is a loud band. How should I set the gain on the Demeter and CA9 to prevent this again??
Click to expand...

How was your eq set? You definitely shouldn't be seeing the clip light flickering constantly. That is a problem. You should set your gain and eq so that at your absolute very loudest you just might see the clip light come on. I would run both channels of the CA-9 at almost full, just slightly backed off from full, and adjust the gain and eq of my preamp so that I wasn't clipping. This will give you the most useable headroom without blowing your speakers.

If I'm wrong, somebody please correct me. However, I ran my CA-9 and preamp like this for many gigs and never had a single issue. That was with a loud 7 piece classic rock cover band.
 
#8
Tony G said:
How was your eq set? You definitely shouldn't be seeing the clip light flickering constantly. That is a problem. You should set your gain and eq so that at your absolute very loudest you just might see the clip light come on. I would run both channels of the CA-9 at almost full, just slightly backed off from full, and adjust the gain and eq of my preamp so that I wasn't clipping. This will give you the most useable headroom without blowing your speakers.

If I'm wrong, somebody please correct me. However, I ran my CA-9 and preamp like this for many gigs and never had a single issue. That was with a loud 7 piece classic rock cover band.
Click to expand...


EQ was almost flat......maybe a tad, and I mean a tad, of treble and bass boost. I am wondering if the signal from the Demeter is too hot. Is there an internal potentiometer in the Demeter for signal adjustment?? The clip light wasn't a constant, nor was it fully lit. It would ever so slightly come on and go off..........I used to operate my amps that way........full on and pre to adjust volume.
 
#10
I agree with the feller who says, "if you like the sound of the ACME's, fix the broken one and add another one".
They do sound great....
Too bad you didn't add another sooner, you wouldn't have had to push yours beyond it's limits. :bawl:
 
#11
jeff7bass said:
I agree with the feller who says, "if you like the sound of the ACME's, fix the broken one and add another one".
They do sound great....
Too bad you didn't add another sooner, you wouldn't have had to push yours beyond it's limits. :bawl:
Click to expand...


I agree..........stupid guitar players, why do they have to play so loud:scowl:!!!!

I think adding a B2 is what I need (in addition to fixing my drivers)
 
#12
You may want to consider looking into a steep high pass filter if you have not already (or if your preamp doesn't have some low end rolloff built in, lots of them do).

Me, I'd consider going to 3015Lf style cabinets. They're going to handle as much power at a lot less weight (two 3015Lfs can swallow 900 watts of 4-string signal and my cab weighs around 70lbs). Also, it's a good deal more sensitive than the Acme IIRC, maybe 4-6db.
 
#13
You're running into the same problems I did when running Acme's with a loud band.

They CAN work, but sometimes they just aren't right for a particular situation.

If you need to cut through the loud guitars, IMO, Acme's aren't really built for that.

I switched from Acmes to a Berg NV610 and immediately cut through the mix...and used much less power to do it.

Your options are to either replace the drivers and keep using the cab...but work on your eq a bit more and your gain settings...or you can sell the empty cabinet. If it would cost more for you to replace the drivers, that might be your only option.
 
#15
Mo'Phat said:
You're running into the same problems I did when running Acme's with a loud band.

They CAN work, but sometimes they just aren't right for a particular situation.

If you need to cut through the loud guitars, IMO, Acme's aren't really built for that.

I switched from Acmes to a Berg NV610 and immediately cut through the mix...and used much less power to do it.

Your options are to either replace the drivers and keep using the cab...but work on your eq a bit more and your gain settings...or you can sell the empty cabinet. If it would cost more for you to replace the drivers, that might be your only option.
Click to expand...

The problem is the cabs sound soooooo good:bassist: But, +1 with the loud band thing. I really dont know what else to do with the EQ. I mean I am running a relatively flat and wide 3 way cabinet with a flat eq on my bass and preamp. I should cut through relatively easily. My problem is volume.....I need more!!!!



jeff7bass said:
With all the power he's got he'll literally double his sound by adding another ACME, although the Berg NV610 is smoking.
Click to expand...

I think that this would be the best option.....although I would lean towards adding a B2 instead of another B4.....unless a used B4 popped up a great price!! I have done the NV610 thing.....not really a fan. Although, I would love to try a NV215. Still, there is a size issue with the 215. Not saying I wouldn't try one......buy they are PITA to lug around. I really like the modular idea if a B4 and a B2
 
#17
I'm not advising to ditch the Acme's and go with the NV610...but it was what worked for me in my band that went from ethereal funk/reggae to punkabilly pretty much overnight. Both guitarists went from Fender Twins to Mesa Dual Rectifier 2x12's (or some kind of beast) and my wonderful Acme sound was relegated to the background. I didn't get any cut at all, and turning up too much drew too much current and popped breakers. Good thing, too, because I didn't blow any speakers or crossover bulbs.

To be honest, the NV610 was not a great bedroom tone cabinet for me, but killed in a loud band setting. Solo'd, all by my lonesome in the studio, it was pretty soulless with my preamp/poweramp setup (at the time, a Bass PODxt Pro and the PLX 3402) so I went with a Mesa 400+, and it still lacked the depth and tonality I really dug when I solo'd my Acme's.
 
#18
You are not alone! I am on my second set of replacement drivers in my B2. I am getting hypersensitive to using it anymore. And, yes, I have been very careful with it power-wise. If I crease another driver, I don't want to replace it again. Then I have a cab I can't really do anything with.
 
#19
If you're set on the B4, I think that maybe adding a B2 would help with the added mid and tweeter. You still may find yourself not being able to cut through the guitars, though.

As for what to do with EQ, you might have to look to the guitarists for help. Chances are, they're playing with their perfect bedroom tone in a band situation...meaning they're compensating for no bass guitar by turning up the bass knob. When they get into a band situation, they keep their bass knob pegged, then turn up their volume, and bogart all the frequencies that you're supposed to be covering. You can approach it by blaming them for your speakers blowing.

As for you, you might realize that your bedroom tone doesn't work either. Up the mids more than you think you need to, drop the bass frequencies, and turn up. Solo'd, you might sound like a honky, midrange-y mess, but when the band kicks in, it'll sound like a good mix.

Anyway, just food for thought.
 
#20
I blew out my B-2, briding a Stewart World 1.2, 1200 watts into 4 ohms, bit much for a 2x10. :rollno: oops...

Andy was cool to deal with on the phone, I was able to get replacement drivers for a pretty reasonable price ($50 per woofer a few years back). So it's definitely worth fixing!

AFAIC it was my own fault for trying to get a 2x10 to do the work of a 4x10. Sounds like in your case you need even more than that.

If you think you might like to try the cab with a different impedence rating, this would be a good time to make the change. (I know Andy offers that option - $280 for the B4 which I think covers new woofers & crossover.)
 

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