MIKE900 Posted February 15, 2010 Share Posted February 15, 2010 My band are using Alessis multimix12 mixer, through a Yamaha P3500s power amp (crossover set at 125Khz) then 1 channel of amp to 12" tops(300w 8 ohm) other side to 18" subs (JBL 4 ohm 400w) Wer'e running kick, snare and 3 vocal mics. Find we need a bit more vocal power, but mixer fader has hardly any headroom left for lead vocalist. Would another amp be the answer then drive subs with one amp and tops with other. Any ideas or help will be greatly appreciated. Mike Link to comment Share on other sites More sharing options...
Kevin Ross Posted February 15, 2010 Share Posted February 15, 2010 Well into a 4ohm load your amp is putting out 590w or 295w per speaker. Given that they are 300w (rms?) you should be fine with a bigger amp or another amp that puts more power our.What size amp to use is a topic of hot debate but 1.5xRMS is not a bad guide line. First things first, when you say the channel fader is all the way up is the amp clipping as well? If not then the week link in the chain is not the amp and putting a bigger one in will not help. Go back and look at your gain structure of the system and most importantly the singer! With a modern dynamic microphone it is common to be right on top of the mic or a small gap of about an inch. If the singer is a foot away from the mic then you will have to run more gain to get the same output level. Link to comment Share on other sites More sharing options...
MIKE900 Posted February 15, 2010 Author Share Posted February 15, 2010 Well into a 4ohm load your amp is putting out 590w or 295w per speaker. Given that they are 300w (rms?) you should be fine with a bigger amp or another amp that puts more power our.What size amp to use is a topic of hot debate but 1.5xRMS is not a bad guide line. First things first, when you say the channel fader is all the way up is the amp clipping as well? If not then the week link in the chain is not the amp and putting a bigger one in will not help. Go back and look at your gain structure of the system and most importantly the singer! With a modern dynamic microphone it is common to be right on top of the mic or a small gap of about an inch. If the singer is a foot away from the mic then you will have to run more gain to get the same output level.The amp is just about clipping, so I can't turn it up anymore. The back of the amp is set as follows: channel B - Low cut switch activated, crossover freq 125. Channel A - Sub woofer activated, crossover freq 125. amp set to parallel. channel A - subs channel B - tops. Is this right? Am I right that if we did get a second amp then we would just use one amp for tops and one for subs. Link to comment Share on other sites More sharing options...
Shez Posted February 15, 2010 Share Posted February 15, 2010 Am I right that if we did get a second amp then we would just use one amp for tops and one for subs.That's generally the way it would work, yes.What top speakers are you using? Some speakers produce a much higher volume for a given input power than others. If the ones you currently have are somewhat inefficient, you could try swapping them out for some more efficient ones - that will get your vocals louder without having to change anything on the amp front. Although as already pointed out, a little more headroom there certainly wouldn't hurt. Link to comment Share on other sites More sharing options...
dbuckley Posted February 15, 2010 Share Posted February 15, 2010 (crossover set at 125Khz)So thats where I'm going wrong... I knew my system sounded a bit dull... Link to comment Share on other sites More sharing options...
johndenim Posted February 16, 2010 Share Posted February 16, 2010 Pedantic as always David! :huh: Link to comment Share on other sites More sharing options...
MIKE900 Posted February 18, 2010 Author Share Posted February 18, 2010 What top speakers are you using? Some speakers produce a much higher volume for a given input power than others. If the ones you currently have are somewhat inefficient, you could try swapping them out for some more efficient ones - that will get your vocals louder without having to change anything on the amp front. Although as already pointed out, a little more headroom there certainly wouldn't hurt. Wharefedales with 12" celestion 300W drivers in. If we did get a second amp how would chain of connection go from main out L & R on mixer, to connect both amps, and what about crossover? Link to comment Share on other sites More sharing options...
TomHoward Posted February 18, 2010 Share Posted February 18, 2010 Unless you got another matching amp with the same filtering circuitry built into the amplifier, the generally accepted way would be to add an external crossover - so a unit with two inputs (L&R) and four outputs (Mid/High L&R, Low L&R) which would then connect to the appropriate amplifiers. Link to comment Share on other sites More sharing options...
MIKE900 Posted February 18, 2010 Author Share Posted February 18, 2010 Unless you got another matching amp with the same filtering circuitry built into the amplifier, If I had matching amp, how would I connect them up from the mixer?? Sorry to sound so dumb Link to comment Share on other sites More sharing options...
NoiseboyBaldy Posted February 18, 2010 Share Posted February 18, 2010 You could always turn the band level down so that the vocals sit on the top, you can also try making the guitarists turn their cabs away to the side so you have less of them to fight against. If your able to do that, then you may find that your sound system suddenly becomes more defined Link to comment Share on other sites More sharing options...
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