Clarky Posted February 26, 2012 Share Posted February 26, 2012 (edited) I have an Acme 8 ohm 2x10 cab that I have been trying to sell unsuccessfully. Its fabulous sounding (studio quality, a la Euphonic Audio) but not very loud and apparently needs a good 600W through it to push any serious air. The 4 ohm version I am told is plenty loud and is what I should have bought. Question for you more technically minded - is is possible to convert an 8 ohm cab to 4 ohms simply and at relatively low expense (obviously via an electrical specialist not by an idiot like me!)? I am sure I could get it done if I sent back to the manufacturer but thats not an option as Acme are in the US. Edited February 26, 2012 by Clarky Quote Link to comment Share on other sites More sharing options...
Dave Tipping Posted February 26, 2012 Share Posted February 26, 2012 Pull one of the speakers out and find out if it's 8ohm or 16ohm .. if it's 16 then the answer is no. If it's 8ohm then yes you could. To find out you'll need a meter if it doesn't have it printed on it. Quote Link to comment Share on other sites More sharing options...
Mr. Foxen Posted February 26, 2012 Share Posted February 26, 2012 With the Acme cab, definitely can't The speakers are custom so you can't swap them out, and the crossover is complicate and specific tot he speakers. Also an 8ohm 2x10 with 8ohm speakers isn't possible. Quote Link to comment Share on other sites More sharing options...
Clarky Posted February 26, 2012 Author Share Posted February 26, 2012 OK thanks Mr F, sounds like a no-no. Thanks gents for your replies Quote Link to comment Share on other sites More sharing options...
Dave Tipping Posted February 26, 2012 Share Posted February 26, 2012 it is if it's a passive radiator design Quote Link to comment Share on other sites More sharing options...
obbm Posted February 26, 2012 Share Posted February 26, 2012 It will either be 2 x 4-ohm speakers in series to make 8-ohms or 2 x 16-ohm speakers in parallel to make 8-ohms. Either way you can't rewire it to be 4-ohms. The Laws of Physics won't let you. Quote Link to comment Share on other sites More sharing options...
Clarky Posted February 26, 2012 Author Share Posted February 26, 2012 Thanks Dave, ho hum. Looks like a great sounding practice (as opposed to gigging) cab on my hands for the foreseeable future then! Quote Link to comment Share on other sites More sharing options...
obbm Posted February 26, 2012 Share Posted February 26, 2012 [quote name='Clarky' timestamp='1330297590' post='1555500'] Thanks Dave, ho hum. Looks like a great sounding practice (as opposed to gigging) cab on my hands for the foreseeable future then! [/quote] if you can't take the impedance down then take the watts up and drive it from a bridged power amp that will deliver oodles of watts into 8-ohms. Quote Link to comment Share on other sites More sharing options...
Mr. Foxen Posted February 26, 2012 Share Posted February 26, 2012 Getting back to the actual problem, dropping the impedance probably won't help you as much as you might think anyway. Quote Link to comment Share on other sites More sharing options...
bigjohn Posted February 27, 2012 Share Posted February 27, 2012 (edited) I agree with the Foxen... I had 2 4 Ohm Acme Low B2s and actually rewired them so they were 16 Ohm. Even that didn't change perceived volume. Though it did stop me blowing fuses and melting transistors in my amp. They just aren't particularly efficient cabs. They sound great, go low and do go dead loud when pushed with the right juice, but they do need the right juice. I much prefer 8 Ohm cabs now. Not sure I'd ever consider a 4 Ohm one again. Edited February 27, 2012 by bigjohn Quote Link to comment Share on other sites More sharing options...
Ed_S Posted February 27, 2012 Share Posted February 27, 2012 Maybe something like [url="http://www.glockenklang.de/en/products/bass_systems/impedance-transformer.htm"]this[/url] would do what you want? Don't know what effect it'd have in practical terms or how much it'd cost to try, but I saw it when I was reading up on onboard pre-amps the other day, so thought I'd mention it. Quote Link to comment Share on other sites More sharing options...
bigjohn Posted February 27, 2012 Share Posted February 27, 2012 (edited) [quote name='Ed_S' timestamp='1330353830' post='1556030'] Maybe something like [url="http://www.glockenklang.de/en/products/bass_systems/impedance-transformer.htm"]this[/url] would do what you want? Don't know what effect it'd have in practical terms or how much it'd cost to try, but I saw it when I was reading up on onboard pre-amps the other day, so thought I'd mention it. [/quote] The function of that box is allow you to connect speakers or arrays of speakers into amps with different impedances without causing damage isn't it? What I'd be doing with 2 4Ohm Acmes is doing what I did with them. Turn them into 2 16 Ohm cabs. Then do what I should have done with them and run them in parallel using a nice powerful bridged power amp at 8 Ohm. Or singly @ 16 Ohm. The problem I found with them @ 4 Ohm (even without a low B ) is the strain they put on the power transistors. Even amps that should be able to run them get very hot! This is because you have to give them plenty of power because of their relative inefficiency and their proficiency at reproducing low end which draws even more power than you think you are hearing. Didn't have a problem at all after they were required. Amps ran noticeably cooler at higher gain. Edited February 27, 2012 by bigjohn Quote Link to comment Share on other sites More sharing options...
Ed_S Posted February 27, 2012 Share Posted February 27, 2012 [quote name='bigjohn' timestamp='1330355787' post='1556082'] The function of that box is allow you to connect speakers or arrays of speakers into amps with different impedances without causing damage isn't it? [/quote] Yeah, appears to be just a matching transformer, so will turn 8 to 4 or vice versa for whatever reason you like. I was more replying to the OP than commenting on your setup, though. Sorry for the confusion - I should have quoted! Quote Link to comment Share on other sites More sharing options...
Happy Jack Posted February 27, 2012 Share Posted February 27, 2012 http://www.soundindustry.co.uk/acatalog/W-Audio-1100W-1U-Amplifier-Horizon1100-47.html I have one of these Clarky - in fact, you played through it for a while on Saturday. If you want to bring your cab round here, you're welcome to fire it up and see what you think as a means of pumping through enough wattage. Quote Link to comment Share on other sites More sharing options...
Clarky Posted February 27, 2012 Author Share Posted February 27, 2012 [quote name='Happy Jack' timestamp='1330357508' post='1556128'] [url="http://www.soundindustry.co.uk/acatalog/W-Audio-1100W-1U-Amplifier-Horizon1100-47.html"]http://www.soundindu...zon1100-47.html[/url] I have one of these Clarky - in fact, you played through it for a while on Saturday. If you want to bring your cab round here, you're welcome to fire it up and see what you think as a means of pumping through enough wattage. [/quote] Thanks Jack, kind offer but I'm not looking to buy another amp. Already got two perfectly decent amps (Markbass F1 and AI Clarus) and was hoping there's a quick/easy/cheap way of converting my cab. It appears not, in which case it remians for sale until such time someone moseys along wanting a clear cab for double bass or for studio use Quote Link to comment Share on other sites More sharing options...
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