la bam Posted December 29, 2011 Share Posted December 29, 2011 [color=#606060][font=tahoma, arial, verdana, sans-serif][size=3] Evening all, Just getting together a larger rig, tops and subs for band and dj, and was wondering if anyone can help with this: I have x2 4ohm tops, x2 4ohm subs and x2 power amps that run at 8,4 and 2 ohm. I want to run all speakers off one amp with the second amp as backup. (i really dont want to use a separate crossover) Ie amp to bass bin with crossover built in, bass bins to tops. Question is: Whats the best way to run the amps to get the maximum 2 ohm? ie bridge, parallel, stereo etc - does it do it itself or do i have to adjust the switches on the back. kit is: Behringer EP2500 - this will be the main amp. Samson SX1800 Peavey UL15 Cerwin Vega 15 SUB In time i'll be getting some 18 subs or 12 tops to balance the system a bit better, but for now this will do nicely. thanks again, [/size][/font][/color] Quote Link to comment Share on other sites More sharing options...
crez5150 Posted December 29, 2011 Share Posted December 29, 2011 To be honest..... I wouldn't run those cabs off of one Behringer power amp..... you are teasing it to trip up. Run two amps.... one for full range and one for subs Quote Link to comment Share on other sites More sharing options...
thepurpleblob Posted December 29, 2011 Share Posted December 29, 2011 well you could using passive crossovers (I assume you are saying that the subs have passive crossovers built in?). However, it seems a bit daft to have the two amps and not use them. Even if you don't crank them up it will give you better quality AND you will have more control because you will be using active crossovers. Your mixing desk may well have the necessary crossovers built in. Quote Link to comment Share on other sites More sharing options...
icastle Posted December 29, 2011 Share Posted December 29, 2011 You can't use the Samson as a backup amp if you want to run all those cabs - it'll only work down to 4Ω and you'll be trying to stick a 2Ω load across it if your speakers are all 4Ω. My inclination would be to get hold of another Samson plus an active crossover and ditch the Behringer. Quote Link to comment Share on other sites More sharing options...
thepurpleblob Posted December 29, 2011 Share Posted December 29, 2011 [quote name='icastle' timestamp='1325198124' post='1480965'] You can't use the Samson as a backup amp if you want to run all those cabs - it'll only work down to 4Ω and you'll be trying to stick a 2Ω load across it if your speakers are all 4Ω. My inclination would be to get hold of another Samson plus an active crossover and ditch the Behringer. [/quote] Well, in theory you could with a properly set up passive crossover (as the signal is split between the cabs for different frequencies) but it's a lot of faff for no (or negative) benefit. Quote Link to comment Share on other sites More sharing options...
la bam Posted December 29, 2011 Author Share Posted December 29, 2011 Thanks everyone, theres so much differing opinion on the net. Some opinions are that the Behringer stats are a bit false and running at 2 ohm is a bit of a lie? Also, theres debate to whether the cv sub and crossover / high pass would in fact spread the load to 4ohm across 2 speakers and not make 2ohm. Even the Samson amp, some places quote in runs to 2ohm. Anyway, to be on the safe side, im going to add an active crossover and use one amp for the tops and one for the sub. Thanks for your help though. Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted December 29, 2011 Share Posted December 29, 2011 Wise, 'sound' decision, imho (pun intended...). Classic setup, should work just dandy and no messing about. Well done (tried sending pat on the back by pm; it didn't work..:-)) Quote Link to comment Share on other sites More sharing options...
Monckyman Posted December 29, 2011 Share Posted December 29, 2011 The crossover and 2 amps setup is def the best choice. You get to balance out the volume of each cab either on the xover outputs, or the amps themselves,making it much easier to get a more tonally balanced rig before EQing. Quote Link to comment Share on other sites More sharing options...
la bam Posted December 29, 2011 Author Share Posted December 29, 2011 I think its the best route, but just a bit disappointing to find out that what these manufacturers claim (ie will handle 2ohm loads etc) isnt exactly 100% true. On the plus side once i get it up and running it should be easy reaching max power with them being 4ohm cabs. Just need a bigger amp rack now - the one i have has no room for an external crossover! Quote Link to comment Share on other sites More sharing options...
la bam Posted December 29, 2011 Author Share Posted December 29, 2011 Just one last thing! The EP2500 is second hand, and has 10 dipswitches on the back. As i dont know in what configuration he used the amp for - what configuration is best for me in the set up mentioned above (ie to power the subs) [url="http://www.retrevo.com/pdf/23214dj390/9/Rear+panel#q=Behringer+EP2500"]http://www.retrevo.com/pdf/23214dj390/9/Rear+panel#q=Behringer+EP2500[/url] Thanks Quote Link to comment Share on other sites More sharing options...
icastle Posted December 29, 2011 Share Posted December 29, 2011 [quote name='la bam' timestamp='1325202099' post='1481019'] I think its the best route, but just a bit disappointing to find out that what these manufacturers claim (ie will handle 2ohm loads etc) isnt exactly 100% true. [/quote] Manufacturer claims about loads are, misprints aside, totally spot on. Where the confusion starts to creep in is where wattage is concerned as there are different ways of working it out. 100W from manufacturer A may actually be louder than 200W from manufacturer B for example. Unfortunately, the maker of your chosen 'main' power amp is a frequently cited example of what I shall politely call 'optimistic specifications'. Quote Link to comment Share on other sites More sharing options...
icastle Posted December 30, 2011 Share Posted December 30, 2011 [quote name='la bam' timestamp='1325202404' post='1481024'] Just one last thing! The EP2500 is second hand, and has 10 dipswitches on the back. As i dont know in what configuration he used the amp for - what configuration is best for me in the set up mentioned above (ie to power the subs) [url="http://www.retrevo.com/pdf/23214dj390/9/Rear+panel#q=Behringer+EP2500"]http://www.retrevo.c...ehringer+EP2500[/url] Thanks [/quote] This should do it: 1= LEFT 2= RIGHT 3= LEFT 4= RIGHT 5= RIGHT 6= LEFT 7= LEFT 8= LEFT 9= RIGHT 10= LEFT I started doing this using 'ON' and 'OFF' but they've fitted some of the DIP switches back to front so that 'OFF' is sometimes 'ON'... Quote Link to comment Share on other sites More sharing options...
la bam Posted December 30, 2011 Author Share Posted December 30, 2011 Thanks very much for your help. Its much appreciated. Good job you mentioned the left/right - on/off - i was just thinking the same!! Thanks again. Quote Link to comment Share on other sites More sharing options...
thepurpleblob Posted December 30, 2011 Share Posted December 30, 2011 Some manufacturers claim that an amplifier will drive the equivalent of a rusty nail but it doesn't mean it will sound any good. You don't get something for free. If you're driving very low impedances then (and this is a gross generalisation) you are looking at a much hotter amplifier and greater distortion. Again, probably best avoided. Quote Link to comment Share on other sites More sharing options...
Monckyman Posted December 30, 2011 Share Posted December 30, 2011 (edited) Just in case you`re interested, in a shameless promotional moment, I have a Furman stereo 4 way or mono 3 way single unit crossover with a few nice features, that `m selling. If you`re interested I could post a few pictures and details? Ad here.. [url="http://basschat.co.uk/topic/163650-furman-active-crossoverstereomono-fs/"]http://basschat.co.uk/topic/163650-furman-active-crossoverstereomono-fs/[/url] Edited December 30, 2011 by Monckyman Quote Link to comment Share on other sites More sharing options...
la bam Posted December 30, 2011 Author Share Posted December 30, 2011 Thanks, but I have got an active crossover in the lock up somewhere, if i have any trouble with it i'll give you a shout. Thanks. Quote Link to comment Share on other sites More sharing options...
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