alexclaber Posted June 13, 2003 Share Posted June 13, 2003 I've sold my trusty (but excessively heavy) Mackie M1400 and I'm planning on getting something lighter to replace it. The question is how much power is safe - I was thinking about a QSC PLX 2402 which would push 700W into each B2, but then I noticed that BenLoy drives his B2 with 1200W!!! Has anyone out there tried the Acmes with a variety of power amps and found they reach a point where the extra power makes no difference, i.e. the cabs have reached their maximum acoustic output? If so, what is that point? BenLoy - how hard do you push the Acmes with the Stewart, does the clip light over come on? How would you describe your live sound - are you a more midrangey Stingray player or more bottom heavy? And that SansAmp you have - what sort of distortions do you get from it, any incidences of the mid/high protection lighting up? Questions, questions, questions... Alex Barefaced Ltd - ultra lightweight, high ouput, toneful bass cabs Link to comment Share on other sites More sharing options...
BenLoy Posted June 13, 2003 Share Posted June 13, 2003 If the clip light ever came on, it would be after my cabinet had exploded! I use 1200 Watts because of the headroom it provides. The Stewart doesn't weigh that much and there's no danger of me hitting a note really hard and having the amp "fart out". How many Acmes do you have, so I can answer your question better? Link to comment Share on other sites More sharing options...
rumpelstiltskin. Posted June 13, 2003 Share Posted June 13, 2003 c'mon, alex. we've been thru this together already. you can put 700W to each cabinet fairly safely. i mean, the manufacturer recommends at least 500W for the 350W rated speakers. honestly, you'd probably be safe putting up to 1kW or more as long as you were careful about the amount of low bass you had in your sound. but you'd be fine with 500W to 700W. i wouldn't worry at all. my carvin 1x15 cabinet is rated for 300W at 4Ohms. i powered it with one side of my former crown K2. that's 800W. and i never heard it fart, distort, or complain. ever. if a carvin can take that, you know an acme can take it, too. robb. because i like people. Link to comment Share on other sites More sharing options...
alexclaber Posted June 13, 2003 Author Share Posted June 13, 2003 Originally posted by robb.: c'mon, alex. we've been thru this together already. you can put 700W to each cabinet fairly safely.I know we'd concluded that 700W would be fine, but as a PLX 3002 is no heavier and similarly priced to the 2402 I've been wondering whether that would be a wiser long term choice. That would put 900W into the Acmes, but would it sound any louder or better? That's the question. At some point I expect I'll replace the Acmes, probably with the most powerful, lightest, most hifi cabs around at that point (eg. if I had the money to upgrade later this year I'd get a pair of EA NL210 cabs). As the power handling of cabs is still going up it seems wise to get as much power as possible. Also, I'd quite like to have an amp that can drive a lone B2 to sufficient volume for smaller gigs. As it would be completely crazy to bridge a 2402 into one B2 (2400W is definitely too much) I'd just run it off one channel, so I'd like enough power to achieve that volume level. BTW BenLoy, I have two Low-B2 cabs and I've always used them as a pair, but it'd be nice to leave one at home sometimes. Alex Barefaced Ltd - ultra lightweight, high ouput, toneful bass cabs Link to comment Share on other sites More sharing options...
rumpelstiltskin. Posted June 13, 2003 Share Posted June 13, 2003 Originally posted by C.Alexander Claber: I know we'd concluded that 700W would be fine, but as a PLX 3002 is no heavier and similarly priced to the 2402 I've been wondering whether that would be a wiser long term choice. That would put 900W into the Acmes, but would it sound any louder or better? That's the question.louder? no. you pretty well have to double the wattage to increase the volume noticeably. but more power means more headroom, which is always nice. that translates to better sound at the same volume levels, and maybe just a little bit more at the high end of the power spectrum. PLX amps are a little weird, but either way, i think you'd be happier with the 3002. but that means i'd be happier if you ran in dual mono instead of bridged mono. [qb]At some point I expect I'll replace the Acmes, probably with the most powerful, lightest, most hifi cabs around at that point (eg. if I had the money to upgrade later this year I'd get a pair of EA NL210 cabs). As the power handling of cabs is still going up it seems wise to get as much power as possible.most hi-fi cabs seem to be rated fairly low in power compared to SWR's 700W ratings. i think you'd be fine with whatever amp you get, as long as it's in the realm you're already talking about with your acme. robb. because i like people. Link to comment Share on other sites More sharing options...
alexclaber Posted June 13, 2003 Author Share Posted June 13, 2003 Just been thinking about how one defines power handling. My possibility some way off the mark ramblings commence here! The LF peak power handling is determined by the excursion of the speaker (Xmax) and the RMS power handling is determined by the ability of the voice coils to dissipate heat. As the rate of heat transfer from the voice coil increases proportionally with the difference between ambient temperature and voice coil temperature then the hotter the voice coil can get without melting, the more power it can handle. The larger the voice coil area (i.e. voice coil diameter x voice coil length x pi) the greater the rate of heat transfer from the voice coil. The important factor when determining how much power a bass cab can handle is the type of signal going into it, because that determines how high the average power level is. With PA speakers playing typical music it's deemed safe to put twice the RMS power into them, hence the 'program' power rating of speakers. However it's pretty unlikely that a bass signal of the same peak power would exhibit the same average power as music, it's much more likely have a much more varied signal level. With slap bass playing this is much more extreme. Now with my Mackie I have played gigs where I had my compressor pedal cranked (8:1), my whole signal chain cranked, the bass boosted and the Mackie has been riding the limiters all gig - if I'm not mistaken that kind of signal would have a much much higher average level compared to peak level than a typical bass signal. Assuming one channel of the Mackie (500W RMS, 1000W peak into 4 ohms) puts out 75W average with a bass signal (though at these gigs I swear the level meter spends it's whole time at -10dB or above), compressing the signal 8:1 should raise the signal level by 9dB, riding the limiter should add another 3dB, thus the average power should go by 12dB, i.e. up to about 800W - that can't be right, that's scary. Even so, it's got to be well above the rating of the cabs. Anyway, the point of this rambling is to say that as long as I don't do the same thing with a much more powerful amp that I did with the Mackie, then the Acmes should handle it. That's in terms of heat dispersion. And I do believe that's less likely to happen because the louder peak power that the amp and hence the cab is putting out should allow the bass to cut through the mix better at a lower average power level. The only other risk is one of over-excursion and lots of people seem to drive a single B2 with 1000W+, i.e. 2000W+ peak and I haven't heard of an Acme driver blowing through over-excursion, only from voice coils melting and I can only think of one incident of that IIRC. Bring on the power, these suckers are going to get near 1000W each. As long as I don't letany neanderthals borrow my rig that should be fine and dandy! Alex P.S. Y'know, I often get the feeling I'm talking to myself on here. Ah well, better than trying to explain this to my girlfriend... Barefaced Ltd - ultra lightweight, high ouput, toneful bass cabs Link to comment Share on other sites More sharing options...
BenLoy Posted June 13, 2003 Share Posted June 13, 2003 P.S. Y'know, I often get the feeling I'm talking to myself on here. Ah well, better than trying to explain this to my girlfriend...She'd be bored to tears, I'm sure...almost as much as mine is. Link to comment Share on other sites More sharing options...
rumpelstiltskin. Posted June 14, 2003 Share Posted June 14, 2003 Originally posted by C.Alexander Claber: Bring on the power, these suckers are going to get near 1000W each.woo! that's what i'm talking about! robb. ps...my wife is very polite in that she actually listens, but i notice she doesn't ask many questions... because i like people. Link to comment Share on other sites More sharing options...
getz out Posted June 14, 2003 Share Posted June 14, 2003 I have two Acme B-2's (4 ohms), and I throw a Stewart World 2.1 at them. 650 watts at each of those puppies, usually with the level on the Stewart about half way up. They sound juicy. Clips when I go apeshit, but that's my fault. I've seen the limiter bulb a couple of times, usually when I'm slapping without a compressor (duh). Notice, I use MINIMAL equalization. I plug my Thumb 5 into my Demeter preamp; I use no EQ on the Thumb bass, and VERY minimal EQ on the Demeter (bass flat, mid at 10:30-ish, and hi at 1:00-ish). I also cut the mid and tweeter slightly on the cabinets attenuator, nothing drastic. Simple, but JUICY. Only an observation, and maybe BenLoy or other Acme users can chime in here, but boosting the bass on your preamp makes the Acme cabs sound like microwaved shit tastes (assumption, not from experience). If you're throwing 500 - 1000 watts at the Acme cab, and not boosting the bass EQ, you should be fine. If you want a more "bassy" sound, you're better of CUTTING, and not boosting, the EQ (ie, cut the mids or the highs). Me personally, I've fallen in love with that "cut-through flat responding sizzle" I get with a minor mid dip and a mild high-end boost, leaving the bass flat. Maury Spadoto Hoboken, NJ Link to comment Share on other sites More sharing options...
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