Need More Power?
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Posted on Jan 09, 2008 09:04 am
Kaiwios
Member Since: Jan 09, 2008
My problem is i'm running a peavey 16 channel board, a crown 602(down to 2 ohms)(840 watts) and 2 peavy speakers on each channel. The guitarists 100 watt cab. always drowns everything out. so i guess i have a couple questions. 1. Do i just not have enough power for a pa, i understand it takes alot to run a system, but i wouldn't think that the guitarist would walk all over it like that. at this point i don't eq any of the fronts, seem like i always lost more power that way. my second question is which would be louder 2spks @ 2ohms @840wtts(does it split the wattage) or 1spk @ 4ohms @ 600watts? Basically i need more power out of this system and any help would be apprciated!!!
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Jan 09, 2008 11:48 am Ok. You do have a couple of problems here. First. Your crown amp is only rated for a four ohm load. So by putting a two ohm load on it, you are allowing the current to flow at to high of a rate. This is clipping the amp at a lower wattage. Second. Yes, an EQ will limit the power going to the amp. But, it will remove the freqencies that are to high in level. Making the responce flatter. This translates to the horn not taking your head off at 2.5k or even 4k. Third. Gain structure. If having resloved all these other issues, and the gtr. is still to strong, lower the gain. If the gain is all the way down, and it is still to much, get a in-line -30DB pad to put on it. This will help tramendiously for your over level. Also, if you are recording from the board, this will give a better repersentation of what was happening in the room at the time.
TadpuiI am not a crook's headMember
Since: Mar 14, 2003
Jan 09, 2008 12:17 pm Ugh, the 100-watt guitar amp. The bane of sound guys everywhere.
Do everybody a favor and convince the guitarist to either buy a power attenuator or a lower wattage amp.
Jan 09, 2008 02:22 pm thanks so much for your answer, but it doesn't quite tell me everything. i have double checked my crown manual once again and it is stable down to 2ohms in stereo and 8ohms briged. it is in the recomended output load sectino in the specs. The two things i'm having the most trouble with is the vocals and kick drum. it didn't seem any better when i ran just one speaker on each channel at 4 ohms. i am an ametuer when it comes to sound, but not a newbie. in my earlier post i asked about splitting thwe wattage, in other words if i am putting out 840wtts. into 2 speakers is each speaker getting 420 watts or do they both get 840 watts. This is for a live application and we are a rock band, so my next questio is , is that just not enough power? we had a sound guy come in to do sound for us and he brought in 5000-7000 watts, not that was loud, i would think that 840 would put the vocal out there pretty good or am i just wrong!!! thanks for all your help
Jan 09, 2008 02:27 pm You need to do two things based on what I have read here:
1- smack your guitarist in the back of the head and tell him to grow up...
2- get an EQ to properly ring out the room and EQ will remove some power, but it'll also raise your headroom. Every now and then a ringing out can add LOTS of volume by simply getting rid of back frequencies so you can turn up louder before feeding back.
Jan 09, 2008 02:34 pm meant to say "now that was loud"... also this might help... i have a peavy 16fx i run compression on the lead vocal.. eq on the vocal sub group(4 mics).. crossover on the board crossing over at 80hrtz into a crown 602, from there one channel goes to 2 peavey 215 cabs(2-15's and horn 4ohms each) and 2 old peavey subs which are 2 12's in each(in very big boxes). all i am running through the board is vocals(4 mics), bass for deeper tone and kick drum. no feedback but can't get the vocals over the guitar and drums, the kick drum i get plenty of slap but no low end without clipping.. thanks again
Jan 09, 2008 02:43 pm on more thing... sorry guys... i am talking mostly in a practice situation also but i have played out with this gear and did'nt think it was loud enough not the chest pumping loud like i hear other bands play and they don't claim to have much more thatn me... i do ring out the sytem through the vocall subgroup... could this be the wrong way to do it?
Jan 09, 2008 02:46 pm I have always used a minimum 30 band EQ, had the main outs of the board going into it, then going out of the EQ into the amp. If you have fewer bands ringing out effectively is hard.
Jan 09, 2008 03:09 pm Ok, before I go on here, let me clear up on thing that I see in a lot of post. Wattage means nothing!!! Wattage is a measurement of electrical power not volume. SPL (Sound pressure level) is our big thing in the audio industry. I can throw 10,000 watts down the line and if my speakers are inafficant, then it will not get any louder. What you are having a porblem with is SPL. I looked on crown's web site before I reponded to your post. According to what they are saying, the amp has an 8 and 4 ohm rating. If on your booklet it says differant, well good. You can then put 2 ohms on it. And yes, if you are running bridge, then each speaker is seeing the 840 watts. From everthing I just read on your post, you are having an SPL problem. This can be fixed one of two ways. The first way is more expensive. This requires you to purchase more gear. Because, in order to double the SPL, you must double the amount of speakers. Therefore, if you have 2, then you must have 4 to double the SPL. If you have 8 then you must have 16 to doulbe the SPL. The second way is gain structure. Gain sturcture and stage volume is everything! You have no room left for you vocal, because the kick drum has sucked all of the head room out of your PA. Why? Because you are trying to get the low end up load enough for people to hear it from only 2 speakers on a stick. Wheather they are 12" or 15" won't matter. There are only 2. Trying to move 60hz or 80hz through 2 speakers in the air. Takes a lot of energy. The only way you are going to get the audiance to hear the vocal, is to lower the kick in the mix, and lower the stage volume. This means the kick will not be in your face. You need sub's and a few more speakers to do that.
Jan 09, 2008 04:18 pm thanks guys... thats a big help... onemore question if i may... to eliminate feedbackk is it better to have the monitors closer with less volume or farther with more volume... or is it both the same effect and for live sound " the kick drum"... better to mic it close to the batter head or farther away?
Jan 09, 2008 04:27 pm Well, for the monitors, a 31 band EQ will take out a lot of the feedback. With out one, move the monitors back some. That will help eliminate some feedback, not all. For the kick drum mic. Depends. I found a Beta 91 works better in the middle. A Beta 52 with just the wind screen just poking into the front head. And an M88 around the middle. General rule of thumb is, closer to the beater, the more attack (Click) the father away, more low end. But, no law saying that you can't use two.
Jan 09, 2008 10:42 pm Dude! I just looked up the rest of your system. The top boxes are rated at 123.5 db. So, you can get 127 db out of your system. And your running out of head room? I looked up your subs. Looks like they might be bass guitar cabs. Not sure on that. But, that could be part of the problem. Tops over rideing the bass. From what I am looking at here, I am not sure where you problem lies now. At 127 db, you should be killing the vocal. I see you mentioned a compressor. Where do you have the settings at?
Jan 10, 2008 09:15 pm Ok.. i'm getting some of this and have read your other posts. I appreciate you taking the time to look stuff up for me... I guess i just have got the "light bulb" over my head yet. have a couple quick questions and then i will get back to my system. I am still not understanding the relationship between wattage and how much you(or I) need to achieve the spl level of 127db. is that what the rms is for my speakers.They are 700 continuous 1400 peak ... When i first started on my pa sytem i had an amp that was 130 watts per channel. now... i think i am pushing 840 from the amp into two speakers... it is noticable louder. therefore the spl level between the two must be different, right?
Back two my pa... i'll tell some more about my board, before i ran the compressor i was having peak problems. we play on a 12x10 4" tall stage with the fronts facing us.. we can't here the vocals clearly over eerything else and the bass drum is not kicking like i think it should be.like i said i use a beringer 15fbeq for the vocal group... the vocals sound good... just not loud enough... could it be that i have rang out to many important freqs. for the voals... i have dropped 2khz and 4khz quite a bit for feedback. I run a compressor that is in the digital effects on the board in a patch through the lead vocal channel... with the output of the effect on unity(could it be that i should run it full open?) I am slamming the compreeor pretty hard to try to prevent clips, i'll have to check next practice but i think threshold=-3.5db knee=hard ratio=10/1 gives my a choice of some compressor types by name... haven't messed with it and output limiter at-2db. the kick drum run into the board looped into one side of the 15 band eq with everything from 120 down on flat and everything else dropped plenty os crack... no low end... mic'ed about halfway in the drum with a nady kick drum mic... the bass cab i'm usin are the bottoms from some old peavy mark IV's rated 117 db thanks again!!
Jan 10, 2008 09:29 pm oops.. i sad peavey markIV... they are acually the bottoms from EV Sentry IV A speakers
Jan 10, 2008 10:08 pm Wow. This system sounds vary filmiluar. You don't by chance live in N.J.? And may have bought the speakers from a guy by the name of Steve? Either way I think we are getting to heart of the problem. Using 15 band EQ's as an insert does limit the gain. By dropping frequencies, your also dropping voltage. So take that out of the kick and vocal channels. Next, 10:1 is a very hard raito. I know your trying to stop the clipping, but, that is very hard ratio. Try this, and see what happens. Take the thereshold to -10. Keep the hard knee. And move the ratio to 5:1. Now, turn the gain on the vocal channel down. Turn the attack on the compressor to around 60 ms. The release to around 150 ms. With all this in place, remove the insert for the compressor. Set the vocal gain to unity. Now reinsert the comp. Check the gain again. If it droped, raise the output gain of the comp until it reaches unity agian. Still run the vocal in the sub group. It adds noise, but it also adds a little gain. Moving on. Yes, you are running the speaker at 840 watts. This is a whole lot better than 150! Your speakers are rated at 700. This means that you need at least 300 just to move them. I noticed that you did not mention a crossover. Do you have one? If not, get one. If you are trying to run all the speakers on just one amp. Then we have found the problem. If you do have one, lower the level of the top boxes and raise the output at the board. For the kick, a gate will help with the sound. The parametric EQ should be enough to get the sound you want. Try all of this and let me know how you made out.
Jan 10, 2008 10:37 pm Ok, found the part where you said that you were crossing the speakers. One question. You using one on the board!?! Never heard of that one.
Jan 10, 2008 10:45 pm No... not from jersey...lol i will try everything you said... as far as the crossover... my board has one... i cross it over at 90hz i still want to get some bass out of the peavey 215's.. they ar not bi ampable. so it goes like this board----highs(90hz and above)--- channel one of the crown amp----- 2 peavey 215 cabs... lows(90hz and below)---channel 2 of the crown(xls 602)---2 EV Sentry IV( They are just like the EV eliminator cabs only with 2 12's in each)
Jan 10, 2008 10:48 pm peavey 16fx board has outgoing processor for daul mono, stereo,crossover... it also has delay(not used) feedback ferret (not used) and grphic or parametric eg(not used) all for outgoig signal only
Jan 10, 2008 10:48 pm I have never heard of a crossover on a board before. That is a definate new one on me. How many outputs does it have? And, does it have phase revers?
Jan 10, 2008 10:55 pm Just looked at it. Wow, that is differant. But, go ahead and raise the output to the bass. See if the board will let you slide the crossover point to 125 to the subs, and 75 to the tops. Get a little over lap in. See if it makes it a little more punchy.
Jan 10, 2008 11:03 pm its a fairly new board.. it has 2 digital effect processers and then the outgoing processor.. it also has usb to connect a hard drive and usb to connect to a computer... the drawback is the manual sucks.... doesn't tell you nothing about it really just the what the knob are and the specs. even on the peavey website... same manaul. i think i did see something on there about phase or polarity in the crossover... you edit everything on a little 2X2 screen the effects like delay and deessr for the vocals is nice but i don't know how well the compressor and the crossver reaooly work since its all digital
Jan 10, 2008 11:06 pm that is one of the bad things about it....only one reference point to crossover... but i will look again to make sure.... when i crossover at 125 it makes the EV"S rumble, but maybe i could take a little of the rumble out with an eq
Jan 10, 2008 11:23 pm Yeah, don't worrie about it. If it won't slide, then the tops are not going deep enough. Put it around 80hz. Let the tops get full range.
Jan 11, 2008 01:13 pm There is one more thing that just came to mind. Do you have a way of checking the individual phase of each speaker? It's a small chance. But, one of your speakers could be out of phase. If you can't phase check them, then open each bass bin. Look to make sure that the positive for each speaker has the same color on it.
