Engineering for live music question[views:3662][posts:14]_______________________________ [Jan 5,2012 9:01am - xmikex ""] I have this job that pops up once a year at work. It's basically a bunch of live performances from students/faculty in this big study lounge where they remix pop songs with lyrics about their professors, whatevs. A handful of the performing acts over the last year or two have started asking for monitors since it's this big high ceiling-ed room and they're usually playing out of combo amps, and they're convinced that it shouldn't sound like combo amps in a study lounge. Anyone who has seen any of my bands over the years should know that technical nuances of live music are not my specialty, and monitors are for destroying. So my success trying to get the monitors to work has been limited. I've been working with a Behringer Europower PMP5000 (specs and manual available here: http://www.behringer.com/EN/Products/PMP5000.aspx). I thought I had it figured out where it has a mode where the main outputs turn into mono signals where one goes to the main speakers, and the other goes to the monitors. The client always insists on 4 main speakers though and there just isn't enough power to make that work. Do I need a separate powered amplifier for the monitors? I have a another smaller PA head and enough cable/speakers to make just about anything work. Any help/suggestions would be appreciated. |
| _____________________________________ [Jan 5,2012 9:36am - the_reverend ""] the monitors don't have amps built into them? |
| _________________________________________ [Jan 5,2012 9:59am - largefreakatzero ""] I have a cheaper version of that Behringer -- that mono/main/stereo horseshit can be confusing. I think you'll need another amp to run your monitors properly. You should be able to run your main outputs into your main speakers, then do a preamp output to a power amp to your monitors. Take this with a grain of salt, I haven't dicked with that head in awhile. |
| ________________________________ [Jan 5,2012 10:28am - xmikex ""] the_reverend said:the monitors don't have amps built into them? I should have clarified. This is not a thread about taking photos of monitors. |
| ______________________________________ [Jan 5,2012 10:57am - the_reverend ""] The only monitors that I used either had an amp built in or were headphones. |
| __________________________________________ [Jan 5,2012 11:01am - joeyvsdavidlopan ""] How much power are your main speakers needing? You could potentially just hook up two speakers, one running into the other, from each main output. For monitors, you can run from the Monitor outs (I think the manual says there are two on the 5000) into your PA head and then run your monitors off that, reserving the rest of your power for the mains. |
| __________________________________________ [Jan 5,2012 11:02am - joeyvsdavidlopan ""] Not that that would use any power, since the Monitor outs are unpowered. Mleh. |
| ________________________________ [Jan 5,2012 11:06am - xmikex ""] the_reverend said:The only monitors that I used either had an amp built in or were headphones. I don't have active monitors available. Just passive speakers that I'm using as monitors. |
| ________________________________ [Jan 5,2012 11:11am - xmikex ""] joeyvsdavidlopan said:How much power are your main speakers needing? You could potentially just hook up two speakers, one running into the other, from each main output. For monitors, you can run from the Monitor outs (I think the manual says there are two on the 5000) into your PA head and then run your monitors off that, reserving the rest of your power for the mains. I usually run each main to a speaker, and then daisy chain each of those speakers to an additional one. I keep one pair at the front of the stage, and another one towards the middle of the room (it's a big room) that way if someone thinks they're Tom Jones and does something stupid I can kill the front speakers and try to avoid feedback. |
| __________________________________________ [Jan 5,2012 11:15am - joeyvsdavidlopan ""] That'll work for the mains, so just use the Monitor send (it looked like they were 1/4" jacks) to send to your smaller head, and run monitors off that. It looks like each channel has a separate level control for what's going to the monitors, so you can even make a half-assed mix if you feel so inclined. |
| _______________________________________ [Jan 5,2012 1:05pm - josh_hates_you ""] You listed the specs for the amp but not the speakers. This is important. That amp is only 300 watts left and right @ 8 ohms and 600@ 4 ohms. Sounds like you are chaining the 4 speakers so you are getting 300 watts @ 4 ohms per speaker. For a large room that isn't much. You would need a second amp to power monitors. unless you have 2 mains and 2 monitors. then you could run 2 off each side. you would need to run you mixer in stereo, not mono to acheive that. you can use the monitor send or the aux sends to feed your second amp with the monitor mix. |
| _______________________________________ [Jan 5,2012 1:08pm - josh_hates_you ""] also, you might already be aware but do not run 3 speakers off one side of the amp. it will create a 2.66 ohm load. 4 speakers would be ok if that amp supports a 2ohm load but i dont think it does. |
| _______________________________ [Jan 5,2012 1:20pm - xmikex ""] Thanks Josh. The speakers are EV Sx100's 8 ohms 200 watts. |
| _______________________________________ [Jan 5,2012 1:22pm - WarriorOfMetal ""] josh_hates_you said:also, you might already be aware but do not run 3 speakers off one side of the amp. it will create a 2.66 ohm load. 4 speakers would be ok if that amp supports a 2ohm load but i dont think it does. With a solid state amplifier, the difference between 3 speakers and 4 speakers is negligible in terms of impedance, as long as the amp can handle a 2Ω load. |
| _______________________________________ [Jan 5,2012 1:28pm - josh_hates_you ""] I missed the part about you having another pa head. those speakers peak at 800 so the want anywhere from 200-400 watts. 400 being ideal. Assuming your other head is at least 200 watts left and right or at least 400 watts mono it should be fine to power those same speakers as monitors. |