Concerns regarding Acme cabs

[calmb4tehpwn]

I'm about to become the new owner of my first Acme cab, a low B4. This wont change, I'm getting the cab, because it's the most beautiful thing I've ever encountered (beside my beautiful wife, and I just have to have them both under the same roof). So, this being said, what do I need to do to protect the cones?

I've read a few forums today in search of issues with these cabs, and having a preliminary idea, I want to ensure what I plan on using wont destroy my new pretty.

I know I must embrace the 30 - 50 Hz range, and avoid overpowering the 60 - 80 Hz range.

Now, I'm still a nub, so let's walk through my rig, so I know how to do this properly. Ohms are still new information to me, Hz are still a bit outside my grasp. I get the idea, just haven't placed where they all sit, yet.

So! We'll start from the top. My bass.
I have a Lotus Steinberger style headless bass with EMG pickups. I'm not entirely sure what my 3 knobs do, but I sure know not a one is volume. As well as I can tell, it's bass, mid and high, but it could blend between the pickups. This said, my bass has a hot output (so I've been told by a friend and neighbor who has gotten me this far), which led me to my next choice: Preamp
GK 2001RBP. I just bought new, it's arriving in the mail sometime next week. I wanted something reasonably priced ($270 new and shipped, FFS) that sounded good (got to try one out thanks to the very same friend and neighbor) and that included an onboard -10db pad, which it does.
This will be going through a power amp. I don't own one yet, but on my next show I'll be borrowing a friend's Crest. I don't know the model, he may very well throw his hat into this thread and inform us shortly, but I plan on using a QSC RMX 1450, or 1850, maybe a Crown Drivecore 1000 or 1500 if I can find a good price.

So. Don't push the mids and embrace the lows, is what I'm hearing, but I don't have an EQ beside what's onboard the preamp, and what my knobs might very well do. How do I use the para eq on my GK to avoid this terrible amp-destroying range of 60 - 80 Hz? Also, is there something else I should be concerned with?

I plan on running power bridged through my Acme Low B4 into my Eden 210XLT. Should I just go stereo instead, to avoid giving my Eden too much power, in an attempt to feed my power hungry Acme? I really, desperately enjoy the way they sound together, and am willing to build my amp section around keeping this pair. So what do I need to do to ensure I don't blow up my cabs?

I would like a power conditioner (once I track down exactly what it does, beside the basic idea I lay claim to currently.) and an EQ, maybe some effects.

I know there was an Alex who seems entirely too knowledgable on the subject, so I hope through our powers combined, we might summon him to answer our tiny questions with his mighty brain.

Note: I have not purchased a power amp, EQ, or power conditioner yet, so any -specific- brands more suited to this setup, would be appreciated, otherwise general knowledge on how to avoid damage is desperately wanted.

[KAOSBass]

Don't have any answers for you, but I'm in the same boat, I have a PAIR of B4s being delivered today....


will be watching to see what advice you get

[calmb4tehpwn]

Awesome! Have to gotten a chance yet to play through Acmes?

[billfitzmaurice]

The only way to absolutely positively protect drivers is to high-pass at or just below the box frequency, and to limit the power amp output to a specific voltage with a brick-wall limiter, the voltage determined by the maximum safe excursion of the drivers. This is SOP with high end PA, rarely seen with electric bass. The alternative is simple enough: if you hear the woofers strain and begin to fart out, turn it down.

[calmb4tehpwn]

How much do limiters run? I would rather run too much power limited, then an insufficient power and miss the potential of the cabs. I would have to look up the max safe wattage, but that's no problem. I've heard terms like "hi-pass" but I don't know what they mean, or how to accomplish them.

[kai_ski]

Originally Posted by calmb4tehpwn

I plan on using a QSC RMX 1450, or 1850, maybe a Crown Drivecore 1000 or 1500 if I can find a good price.

So. Don't push the mids and embrace the lows, is what I'm hearing, but I don't have an EQ beside what's onboard the preamp, and what my knobs might very well do. How do I use the para eq on my GK to avoid this terrible amp-destroying range of 60 - 80 Hz? Also, is there something else I should be concerned with?

I plan on running power bridged through my Acme Low B4 into my Eden 210XLT. Should I just go stereo instead, to avoid giving my Eden too much power, in an attempt to feed my power hungry Acme? I really, desperately enjoy the way they sound together, and am willing to build my amp section around keeping this pair. So what do I need to do to ensure I don't blow up my cabs?

I would like a power conditioner (once I track down exactly what it does, beside the basic idea I lay claim to currently.) and an EQ, maybe some effects.

Note: I have not purchased a power amp, EQ, or power conditioner yet, so any -specific- brands more suited to this setup, would be appreciated, otherwise general knowledge on how to avoid damage is desperately wanted.

Here's the thing about "pushing the mids". In my opinion Acme makes a very balanced sounding cab, meaning the lows are present as well as the highs and mids. I actually would eq more mids on my head when using the low b2. Then dial back the volume. Mid frequencies cut a lot better through the mix, so basically you can be more efficient. When you scoop the mids, you have to use a lot more power to be heard, and that can also be detrimental to your cab.

Power conditioners are really just a fancy rackmount power strip. Nothing wrong with them, but I would try to find a used one.... they're also not that expensive new. I have one I got a good deal on, but it's just the most basic furman.

Before purchasing a power amp, you'll need to determine how many ohms your acme cab is. If it's 8 ohms, get an amp that will do 700 w at 8 ohms. If you want to run the Eden at the same time, do not bridge the amp into both cabinets. Run them on separate channels. So in that case, if the acme is 8 ohms, you will want a power amp that will do 700 w @ 8 ohms per channel to achieve the full potential of the Acme. You will definitely have to be more careful with the Eden than the Acme.

I use a Face Audio F500TS power amp. I always run it bridged, it does 700 W @ 8 ohms and 1000 @ 4 ohms. I run it through my Goliath III, and I have never had a situation where I'm close to full volume with my 5 piece band (solid hitting drums, keys, 2 guitars,) playing soul, funk, blues, and pop. I even play 200 person halls with no PA support on a regular basis. Crest and Crown make good amps too. I chose Face because it had the largest toroidal power supply of the bunch.

[chucko58]

Originally Posted by calmb4tehpwn

I know I must embrace the 30 - 50 Hz range, and avoid overpowering the 60 - 80 Hz range.

Uh... where did you read this? Link please??

[bassman1185]

I would echo most of what has already been said. You probably don't need to worry too much about the "amp destroying 60-80hz range." I'm an audio tech, and I have never once heard anything like that. Any frequency, if boosted enough, can kill a speaker, but no frequencies that I am aware of will harm the amp itself.

In terms of hooking up both of your cabinets, here is what I would do:

Find power amp that can put out about what your cabinet can handle OUT OF ONE CHANNEL. Your cabinet will handle 700 watts, so you'll want something that can do roughly 700 watts (if not a bit more) into whatever your cabinet is rated at. If you've got a four-ohm cab, that will make your life a bit easier, because to get an amp that puts out 700 watts per channel at 8 ohms means forking out a lot of money.

From there, run from your preamp into your power amp, and set the power amp to combine both channels. You will want it set for "mono," NOT BRIDGED. You'll probably want to assign channel one on your power amp to the Acme, and channel two to your Eden. Set channel one at a medium/high level, and turn channel two all the way down. Try starting channel one at about 75%, but keep the volume on your preamp DOWN. Carefully bring up the volume on your preamp till it's at a functional level. Once you get a good sound dialed in with that cab, slowly turn up channel two on your power amp to start blending in the Eden. You obviously won't be getting as much volume out of the Eden as you will the Acme, but you should be able to suppliment the Acme a little bit.

At least, that is what I would do. I believe that your preamp will allow for biamping, but it seems like that would miss the point of the Acme's full range sound.

[calmb4tehpwn]

What to Do With Creased Acme Drivers?

on pages 2 and 3 AlexClaber speaks in length on the capabilities of acme cabs, and what frequencies they are sensitive to, and those it is built to take. He mentions that the 30-50 range is what it was made to support, but it shows serious weakness against the 60-80 range. I didn't mean I was going to push an unecessary amount of that range through the cabs, but only that I wasn't going to restrict that range, as is one's want to do, when attemping to keep bass from destroying it's respective cabs.

I didn't mean to misrepresent his words, and apologize if I have. If I have not, however, and he is indeed mistaken, then please enlighten me.

[billfitzmaurice]

Originally Posted by calmb4tehpwn

How much do limiters run?

http://www.zzounds.com/item--BEHMDX1600

I've heard terms like "hi-pass" but I don't know what they mean, or how to accomplish them.

Proper Application Of High Pass Filters

[ToneMonkey]

What makes you think you need the Eden cab? Have you spoken with Andy? He spent a lot of time walking me through how much power/SPL volume to expect from certain configurations.

Unless you're playing huge rooms or huge outdoor events, one B4 and 800-1000 Watts of power should be a really good match. I'd try that first. Maybe keep your Eden cab for smaller gigs.

I'm still struggling a bit after switching to a B2. Acme cabs are so darned linear that the first gig really pinpointed some goofy pickup height adjustments I had. I'm hoping to verify that I got that ironed out at this weekend's gig.

[dmusic148]

You are over-thinking things a bit. It really comes down to listening to your rig for signs of stress. If your speakers are straining, you'll hear it.

Next, combining the two cabs you have: we need to know what Ohm rating each cab has, because this will determine if it will work well or not at all in bridge mode. You can certainly run them in stereo and adjust the output to each, but in bridge mode you can run into trouble, as the combined load of the two cabs may be too low for your amp to handle.

Finally, the controls on your bass are almost certainly Volume, Volume, Tone. If not, something is screwy with your bass.

[BassmanPaul]

Am I imagining it but did you not just ask these same questions in another thread???

Use the B4 by itself and don't try to improve how it sounds with an inferior additional cabinet!

[rpsands]

Depending on the tuning frequency of the Acmes it is distinctly possible that the saddle frequency could pop these woofers.

If the tuning frequency is 30hz, the point of maximum excursion will be about 51hz actually, not 60-80hz.

I really have no idea what the tuning frequency is of the Acmes though. If it's around 40hz, that would make 60hz closer to the point of maximum excursion above the tuning frequency.

Hint: In order to use EQ to limit your ability to do damage you would need to know the tuning frequency of the cabinet, and have a precise method of EQ such as a semiparametric eq pedal.

[chucko58]

Originally Posted by calmb4tehpwn

What to Do With Creased Acme Drivers?

on pages 2 and 3 AlexClaber speaks in length on the capabilities of acme cabs, and what frequencies they are sensitive to, and those it is built to take. He mentions that the 30-50 range is what it was made to support, but it shows serious weakness against the 60-80 range.

I just skimmed that whole thread. I read Alex's comments as: it is a bad idea to roll off the 30-50 Hz region AND THEN go heavy on the 60-80 Hz to make up for the lack of bass. Doing so discounts the Acmes' strengths in the low bass and stresses them in the mid-bass where they are closer to their mechanical limits.

I don't consider Acmes "weak" in the 60-80 Hz region, and I've been using a pair of Low B-2 cabs in my main gig rig for 8 years now without a problem.

I am not familiar with the sound of your Eden cab, but if it is tuned like most bass cabs, with maximum output in the mid-bass, I suspect it will complement the Low B-4's low bass output quite nicely.

[alexclaber]

Originally Posted by chucko58

I just skimmed that whole thread. I read Alex's comments as: it is a bad idea to roll off the 30-50 Hz region AND THEN go heavy on the 60-80 Hz to make up for the lack of bass. Doing so discounts the Acmes' strengths in the low bass and stresses them in the mid-bass where they are closer to their mechanical limits.

I don't consider Acmes "weak" in the 60-80 Hz region...

Exactly! Although mine have been gone a few years they'd more than proved their mettle in producing awesome fat loud bass. What I was getting at was that I kept reading about people using highpass filters way above the tuning frequency and it didn't make sense - so I tried it with the switchable 30/50Hz filter on my QSC and with similarly fat bottom you could see the cones jumping more with the 50Hz filter and hear them complain sooner with the 900W/cab that the QSC could provide.

Don't worry about it, just don't crank the bass tons when using a very powerful amp in a band that's so loud you can't hear the warning signs.

[kai_ski]

The Eden might make a good reference cab for large stages if you put it on top of your rig and adjust volume for your ears only. I have seen those Eden 2x10's used for that purpose somewhat often. Other than that, I don't see you needing it in addition to the b4 for small spaces.

[Zooberwerx]

I'm somewhat involved with this project and just wanted to point out that the OP is drop-tuning to low G#. Please feel free to discuss.

Riis

[ToneMonkey]

Goodness. That's a horse of a different color, isn't it. What is that note value ~15Hz.

Originally Posted by Zooberwerx

I'm somewhat involved with this project and just wanted to point out that the OP is drop-tuning to low G#. Please feel free to discuss.

Riis

[calmb4tehpwn]

Oh, forgot to mention that. It's the reason for my inquiry. I'm new in the band, and we have a show NEXT weekend, so I don't have time to learn the songs, transcribe the songs, and learn the songs again. My only course for this show is to play them as is, in the tuning desired by the band.

@bassmanpaul I have asked very different questions regarding the same cabs in my search for a pre-amp that would suit my needs.

@everyone They are both 8ohm cabs, and I am painfully in love with they way they sound TOGETHER. I know popular opinion demands I do not mix these cabs, and I understand that going in. That being said, how can I mix them without breaking my cabs, and without breaking the bank. I will look into the recommended/max wattage for each amp and get back to you. I get the stereo/bridged concern, and I would love to go stereo on this. Completely happy to do it, except that it means I need some serious wattage, which I am in fact okay with.

So, push stereo. Got it. I can safely assume the max wattage for the eden is significantly less than the acme. So, could I run bridged, and take the amp to twice the max wattage of the eden? Am I right in this math? I've been told that the math in such a science doesn't work out to 4/2=2 exactly, so what would be considered outside of -safe- territory?

If I missed any questions, I apologize. I'll run through the responses again and post anything I missed.

Thank you for the valuable resources and information. It's why I've come here.