• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

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

#64
alexclaber said:
Those who've had problems with Acmes in the past might want to keep an eye out for the forthcoming 12" models. Tone should be very similar but the woofers will have higher Xlim and thus be much harder to damage. Lighter too.

Alex
Click to expand...

I will be VERY interested in hearing more about these.

Maybe Andy will even update his site more often than every couple of years....;)
 
#65
bongomania said:
So, why suggest it if it won't help his problem?

Turning down the preamp output does not limit the power amp's output (directly) any more than turning down the power amp's attenuators. Both controls are just passive attenuators in series, there is no cleanliness benefit to using one over the other, unless the preamp output is clipping the power amp input.

Right--no harm, and no difference either! Six of one, half dozen of the other, again with the exception of avoiding clipping at the power amp's input, for which the preamp volume knob really is important. Acme's statement is totally accurate, but it has no bearing on the question of preamp versus power amp attenuators.
Click to expand...

1) Power amp on full and use the controls on the preamp is IMO the correct way to do this. Some power amps don't even have level controls.

2) Neither the pre-amp levels nor the power amp levels turn down the wattage of the amp. Agreed, that's power amp 101.

3) avoiding clipping of the power amps input stage is the whole point of the exercise!

Paul
 
#66
BassmanPaul said:
1) Power amp on full and use the controls on the preamp is IMO the correct way to do this. Some power amps don't even have level controls.

2) Neither the pre-amp levels nor the power amp levels turn down the wattage of the amp. Agreed, that's power amp 101.

3) avoiding clipping of the power amps input stage is the whole point of the exercise!

Paul
Click to expand...


while you do want to avoid clipping your power amp, clipping isn't going to be the cause of speaker damage. Power amp damage yes, but not speaker damage.

Anyhoo, I'm 95% sure that the OP's issue of blown drivers is from the power level to the speakers.

So there are 2 options to correct the issue.

#1. Fix your drivers and add more speakers for more volume (you have more than enough wattage to put a grown elephant into a coma).

#2. Sell the acme and get something else.

I believe it really boils down to that.
 
#67
Bongo, I have read your posts on this site and the vast majority of them are well thought out and helpful. I have no intention of arguing with you over semantics. I firmly believe you post what you consider to be true. However what is true for you is not necessarily true for every one else. I do the same. I've been using a pre/power rig a lot longer than you have and I post what I have learned using those rigs. If what I have learned is different from what you have learned so be it.

Paul
 
#68
jokerjkny said:
as i,

but it's easy in the heat of the moment to take the acmes from "dammit that sounds great" to "holy crap! what is that weird fluttering sound".
Click to expand...

And therein lies the problem. Not a good feeling to have in the back of your mind when you should be concentrating on PLAYING. Which is why I eventually ditched them.

Lonnybass
 
#69
BassmanPaul said:
Bongo, I have read your posts on this site and the vast majority of them are well thought out and helpful. I have no intention of arguing with you over semantics. I firmly believe you post what you consider to be true. However what is true for you is not necessarily true for every one else. I do the same. I've been using a pre/power rig a lot longer than you have and I post what I have learned using those rigs. If what I have learned is different from what you have learned so be it.

Paul
Click to expand...


I'm not arguing about how to setup a power amp.

I'm just stating that we know that his gain setup vs. his volume setup on the CA-9 isn't what caused the speaker damage.

It's that the acme couldn't handle the 1900watts.
 
#71
jeremyr said:
while you do want to avoid clipping your power amp, clipping isn't going to be the cause of speaker damage. Power amp damage yes, but not speaker damage.

Anyhoo, I'm 95% sure that the OP's issue of blown drivers is from the power level to the speakers.

So there are 2 options to correct the issue.

#1. Fix your drivers and add more speakers for more volume (you have more than enough wattage to put a grown elephant into a coma).

#2. Sell the acme and get something else.

I believe it really boils down to that.
Click to expand...

Good grief! Is nobody understanding what I wrote today! I did not even mention clipping being the OP's problem! It IS absolutely too much power that has caused his problem - I already said that!

#1) I alredy SAID that too!

#2) I said that as well - pretty much.

Paul
 
#75
Besides the amount of potential power that was involved, the Acme drivers are a custom OEM mod, derived from a stock Em design, but that had longer XMAX - excursion - than the stocker. Unfortunately when a custom driver like this is spec'd, the XLIM stays the same. The physical limit can't be changed short of a new design entirely. So the distance from xmax to xlim has been shortened. That means the onset of obvious speaker distortion happens at a travel distance is just not that far from the backplate.

...Now that the Kappalites are around with their generous xmax, and a lot more safety zone to xlim, the Acme/Em 10" driver looks like a less desirable choice for a three-way design.
 
#76
Not to slight the Acme LF section either. If one desires more performance below 100 Hz, they are a great choice, pretty far ahead of the pack in that regard. But when shoveling ridiculously huge amounts of power to the woofers one needs to have some safeguards in place if judgment/listening isn't keeping handle on where the limits might be.

Yep - as mentioned, steeper HPF is a solution. As is not expecting a woofer to do more than it is capable of.
 
#77
jokerjkny said:
but it's easy in the heat of the moment to take the acmes from "dammit that sounds great" to "holy crap! what is that weird fluttering sound".
Click to expand...

Heh heh, +1 on that. Was having my best tone moment ever, then... ka-plooey :eek: :mad:

I don't know exactly what I did but one of the woofers would ohm out at zero and send the amp into protect mode. (Guess I fried that sucker real good!! :D)

Life seems simpler with a nice efficient conventional cab w/ the low mid bump. It's not quite the same w/o those ultra-lows, though - they sure were addictive. (Just have to take it one day at a time...)
 
#78
Lonnybass said:
And therein lies the problem. Not a good feeling to have in the back of your mind when you should be concentrating on PLAYING. Which is why I eventually ditched them.

Lonnybass
Click to expand...

oh,

i'm saying this for any number of cabs i own. course, i fixed my particular acme issue by OWNING MORE ACMES. :D but seriously, there was a point where i gigged w/ a B2 / B4 setup. hip hop emcees... yahmean?
 
#79
Jefenator said:
Heh heh, +1 on that. Was having my best tone moment ever, then... ka-plooey :eek: :mad:

I don't know exactly what I did but one of the woofers would ohm out at zero and send the amp into protect mode. (Guess I fried that sucker real good!! :D)

Life seems simpler with a nice efficient conventional cab w/ the low mid bump. It's not quite the same w/o those ultra-lows, though - they sure were addictive. (Just have to take it one day at a time...)
Click to expand...


I wish this would have happened to me a week or so ago so I could have bought your S1 B2

There is a clown on eBay who wants $140 + $70 S&H for a S1 B2 with blown drivers:hmm:. After you spend the the $160 to get new drivers from Acme, you would have around $350 sunk in to the cab......might as well wait for used S2 B2 to pop up.

:eek:12" Acme's........that sounds cool:eek:
 

Latest posts

Top Bottom
Back