Members tlbonehead Posted July 16, 2009 Members Share Posted July 16, 2009 I'm not into the power amp game but I've been bit by this bug. Would matching the sensitivity according to power, gain, etc, blah, blah, blah make them identical in richness, warmth, clarity and all the other words he mentioned about the Crest?Did you somehow skip over all the posts that said to run the gains higher on the PLX to match input sensitivity? Link to comment Share on other sites More sharing options...
Members Unalaska Posted July 16, 2009 Members Share Posted July 16, 2009 I seriously doubt you could tell which amp was which in a double blind test. Amps sound the same when driven in thier normal operating range (non-clip) but they do exibit different characteristics when pushed to limiting and their limiters sound different. p Link to comment Share on other sites More sharing options...
Members Crownman Posted July 16, 2009 Members Share Posted July 16, 2009 How about this as a suggestion. Turn the gains for the highs and lows all the down on the crossover. Run the input of the amps at 100% wide open. Set everything up like you normally would on the mixer and all outboard gear. Board volume out at unity. Turn the system on and then slowly bring up the low & high gains on the crossover until you have the highs and lows balanced like you want at the volume you want to acheive. This should get things where you want them. The crossover should have plenty of tweak room to get the system balanced like you want it. Run the lowest gains you can on the board channels and make up for the extra gain needed in other spots. This can go a long way in helping to reduce feedback problems. Your system has the adjustability to get what you want with the amps wide open. It's starting to adjust things in the proper order that'll make all the difference. Link to comment Share on other sites More sharing options...
Members agedhorse Posted July 16, 2009 Members Share Posted July 16, 2009 Run the lowest gains you can on the board channels and make up for the extra gain needed in other spots. This can go a long way in helping to reduce feedback problems. This has absoluetly no effect on feedback potential of a system. None. Link to comment Share on other sites More sharing options...
Members Crownman Posted July 16, 2009 Members Share Posted July 16, 2009 This has absoluetly no effect on feedback potential of a system. None. After thinking more about it though I see what you're saying. I've had luck though in reducing mic gain on the channel then getting that gain back down the chain. At least for FOH. If I can run a lower gain on a vocal mic or any mic it'll pick up les stage noise. I'll then boost the gain a little on the main eq to get the gain back before going to the DR. Less stage noise in the mics makes a cleaner mix for FOH and monitors since there's not extra stage noise mixed in there. The cleaner the monitor mix the less volume I usually need to run in them, and I have less feedback problems. That was my thinking. It's worked well for me but am I completely wrong with that line of thought? Link to comment Share on other sites More sharing options...
Members MrJoshua Posted July 16, 2009 Members Share Posted July 16, 2009 How does turning down a knob or fader change what the mic is picking up? It changes how much you're amplifying what the mic is picking up, yes, but then if you turn it up again later ... what's different? Link to comment Share on other sites More sharing options...
Members kevinnem Posted July 16, 2009 Members Share Posted July 16, 2009 After thinking more about it though I see what you're saying. I've had luck though in reducing mic gain on the channel then getting that gain back down the chain. At least for FOH. If I can run a lower gain on a vocal mic or any mic it'll pick up les stage noise. I'll then boost the gain a little on the main eq to get the gain back before going to the DR. Less stage noise in the mics makes a cleaner mix for FOH and monitors since there's not extra stage noise mixed in there. The cleaner the monitor mix the less volume I usually need to run in them, and I have less feedback problems. That was my thinking. It's worked well for me but am I completely wrong with that line of thought? where you runnign a dynamics prosessor on the channel in question? RE the gain issue ...... gain is gain, regardless where you put it.... what makes you think the that pre amp gain does anything different then the other gain stages (ch fader, mst fader, "input and output" knobs ... attenuators on amps .... ect) Link to comment Share on other sites More sharing options...
Members Crownman Posted July 16, 2009 Members Share Posted July 16, 2009 How does turning down a knob or fader change what the mic is picking up? It changes how much you're amplifying what the mic is picking up, yes, but then if you turn it up again later ... what's different? If you have a vocal mic gain set on the channel where you get the vocals needed but don't get any stage noise into it. Cool. So you have a clean vocal signal going out of the board with no noise on it. If you then bump up the mixer output on the main out fader does the mic now start picking up drum noise from the stage? It shouldn't because you're now boosting the clean signal, not the sensitivity of the mic itself. I'm not trying to argue here. But if there's some physics info that I just dont know then tell me. Link to comment Share on other sites More sharing options...
Members dboomer Posted July 16, 2009 Members Share Posted July 16, 2009 I've had luck though in reducing mic gain on the channel then getting that gain back down the chain. ... That was my thinking. It's worked well for me but am I completely wrong with that line of thought? Whatever the ratio of intended to unintended sound in you mic is won't get better or worse no matter where you apply the gain ... but ... your overall signal to noise ratio will get worse by adding it later rather than earlier. Best to correctly set your mic trims as they affect everything that comes later. Link to comment Share on other sites More sharing options...
Members MrJoshua Posted July 16, 2009 Members Share Posted July 16, 2009 If you have a vocal mic gain set on the channel where you get the vocals needed but don't get any stage noise into it. Cool. So you have a clean vocal signal going out of the board with no noise on it. If you then bump up the mixer output on the main out fader does the mic now start picking up drum noise from the stage? It shouldn't because you're now boosting the clean signal, not the sensitivity of the mic itself.I'm not trying to argue here. But if there's some physics info that I just dont know then tell me. What's the difference between turning up the channel fader or turning it up later on? You're not altering what's coming into the mic, right? Link to comment Share on other sites More sharing options...
Members Crownman Posted July 16, 2009 Members Share Posted July 16, 2009 What's the difference between turning up the channel fader or turning it up later on? You're not altering what's coming into the mic, right? I agree you're not. I'm referring to the gain trim on the channel itself. There is a difference between turning up the channel gain trim and turning up the fader or something down the line. Same as people boost the output just a tad on a compressor to help get back a tad of gain on a vocal line. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted July 16, 2009 CMS Author Share Posted July 16, 2009 I agree you're not. I'm referring to the gain trim on the channel itself. There is a difference between turning up the channel gain trim and turning up the fader or something down the line. Same as people boost the output just a tad on a compressor to help get back a tad of gain on a vocal line. If you do the makeup gain thing on a compressed mic channel, you will indeed have better gain before feedback if you then reduce gain at the channel trim.....because you're reducing the signal into the compressor, and effectively increasing the compressor threshold. The effect is to lessen compression (the signal doesn't reach threshold until it's hotter. Compressed signals are more likely to feed back because they have more average power than the equivalent uncompressed signal It would be easier to simply keep the channel gain adjusted correctly and raise the compressor threshold. Now to address your thinking on this topic; Gain is gain. A preamp increases voltage. An amplifier increases voltage. These two basic devices exist in several places in the average PA system. Your argument is that increasing voltage (gain) early on is different than increasing it later in the signal chain. In terms of how much output voltage the amplifier ultimately produces (how loud the speakers get), it doesn't matter where you take your gain. In terms of having the best signal to noise ratio, it matters a lot...as dboomer wrote earlier, you should set gain properly at the channel gain. Remember that the mixer, EQ, compressor, crossover all insert a little bit of noise in the signal. The hotter the signal is early on, the more signal there is for a given amount of noise....hence better signal:noise ratio, and a quieter system. Link to comment Share on other sites More sharing options...
Members Crownman Posted July 16, 2009 Members Share Posted July 16, 2009 Yea, I pretty much see it the same way you guys do. I'm just not explaining it in words worth a damn. I apologize for that, I haven't been to sleep since about 9am yesterday. I also didn't realize how old this thread is, haha. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted July 17, 2009 CMS Author Share Posted July 17, 2009 I also didn't realize how old this thread is, haha. Link to comment Share on other sites More sharing options...
Members dboomer Posted July 17, 2009 Members Share Posted July 17, 2009 There is a difference between turning up the channel gain trim and turning up the fader or something down the line. Same as people boost the output just a tad on a compressor to help get back a tad of gain on a vocal line. There is NO difference in the amount of stage wash in your mic no matter where you do it. If you are using a compressor you are almost certainly making the wash a bigger problem and again it doesn't matter whether you apply makeup gain at the compressor or further down the line. Link to comment Share on other sites More sharing options...
Members Crownman Posted July 17, 2009 Members Share Posted July 17, 2009 I'm not doing that, it was just a bad example. Like I said, I'm sleep deprived right now. I shouldn't have been trying to think about this and posting right now anyway, LOL. Link to comment Share on other sites More sharing options...
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