BillFitzmaurice.info

So I've done a handful of gigs now with the newly built rig and feel like I just haven't quite found the sweet spot for this system. I'll admit right off the bat that while I've been running sound for many years I've never run something this large and haven't ever quite gotten a true handle on understanding voltage limits, and how to be sure of where I am based on the settings on my limiter and compressor. I've been digging through the forum and learned some tid bits but haven't been able to put it all together.

My set up is as follows -

From the mixer it goes into a BBE 882i sonic maximizer --> DBX Driverack PA+ -----> Behringer inuke6000 -----> cabs

I'm running 8x 24'' wide T48s loaded with 3015LF's and 4x Omnitop15s loaded with 3015's.

My main concern is that I blew out some drivers during a gig and couldn't really determine why exactly. I was running the system exactly as I had previously a few times and hadn't had any issues and from a bit of reading on the limiters, thought I had them set at a safe level.

I run the limiters at +9-13dB with the "over easy" set to about 4-7. Compression is set to about 3dB. I'm playing recorded electronic music for the most part.

I'd greatly appreciate anyone willing to give me the run down on what voltage limits are on the drivers, and how the driverack and amps are impacting that voltage output, how to read the voltage output, and ways to maximize the sound while keeping the system safe by using the limiter and compressor. I realize this is seemingly basic but please have patience with me.... lol

Ok, here's the down and dirty...

Riflefeet wrote:
From the mixer it goes into a BBE 882i sonic maximizer --> DBX Driverack PA+ -----> Behringer inuke6000 -----> cabs

If you are recording, mixing, or mastering records - move the BBE to the studio and play with it there. If not, sell it and take your wife out to dinner - the money is better spent in that endeavor that using it in a live situation.

I'm running 8x 24'' wide T48s loaded with 3015LF's and 4x Omnitop15s loaded with 3015's.

Excellent choice of drivers

My main concern is that I blew out some drivers during a gig and couldn't really determine why exactly. I was running the system exactly as I had previously a few times and hadn't had any issues and from a bit of reading on the limiters, thought I had them set at a safe level.

You must use a voltmeter to set the limiters - period. There is no other way to do it.

I run the limiters at +9-13dB with the "over easy" set to about 4-7. Compression is set to about 3dB.

There is no "over easy" on the limiter section - that's a compressor function....that tells me you don't have the limiters set properly. The limiters are not there as a tool to make the music sound better in any way shape or form...they are there to protect your gear.

I'm playing recorded electronic music for the most part.

There is no reason to run compression on the system when playing recorded music - it's already had the hell compressed out of it. Turn it off and let the music sound the way the artist intended it...

I'd greatly appreciate anyone willing to give me the run down on what voltage limits are on the drivers,

The voltage limits are in the plans. Current plans call for 60 volts on a 3015LF. You've got 4 of 'em - peel 'em back to 55 for some extra safety....won't make hardly any difference in output.

Another consideration is your high pass filter. According to the plans, a stack of 4 can go to 35hz. But, if you are splitting 'em and trying to hit 'em really hard - then keep the high pass at 40. No need in putting undue pressure on the drivers for very little gain.

and how the driverack and amps are impacting that voltage output, how to read the voltage output, and ways to maximize the sound while keeping the system safe by using the limiter and compressor.

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The driverack controls the amount of signal going to the amp. The amp should be turned up all the way - that way you know that the amp can't be turned up any louder. The driverack clamps down on the amount of signal that is being amplified - thus, if the amp is all the way up and the limiter determines how much input the amp gets - it can't go over that limit.

Again - compressors do NOT protect your system. They are sound shapers. With the music you are using, there is no reason to use 'em. All it does it remove what little dynamics are in the music to start with.

The limiter is set by turning your mixer up to unity with a 60hz test tone running through it. Now, put a volt meter on the outputs of the amp without the speakers being plugged in. In the limiter section of the Driverack, you lower the output until the volt meter reads the proper voltage. To test if it's correct - slam the master fader on the mixer all the way up while watching the meter. It should stay at the voltage that you set.

Thanks for the response bruce, a couple follow ups...

Bruce Weldy wrote: There is no "over easy" on the limiter section - that's a compressor function....that tells me you don't have the limiters set properly. The limiters are not there as a tool to make the music sound better in any way shape or form...they are there to protect your gear.

I'm aware of how compressors and limiters work and how they effect dynamics and hear what you're saying about not compressing electronic music which has been compressed already. However I'm fairly positive that the "overeasy" function on the driverack pa+ is on the limiters. as I understand it, it just curves the attack of the limiter to reduce the sharp cut off effect when you hit your ceiling.

Bruce Weldy wrote: Another consideration is your high pass filter. According to the plans, a stack of 4 can go to 35hz. But, if you are splitting 'em and trying to hit 'em really hard - then keep the high pass at 40. No need in putting undue pressure on the drivers for very little gain.

I've been running my highpass at 35hz as per the plans, but are you saying that the extra 5hz extension is putting a great deal of excesses strain on the drivers? If so running at 40hz makes a lot more sense, does it require more voltage to output the lower frequencies?

Bruce Weldy wrote: The driverack controls the amount of signal going to the amp. The amp should be turned up all the way - that way you know that the amp can't be turned up any louder. The driverack clamps down on the amount of signal that is being amplified - thus, if the amp is all the way up and the limiter determines how much input the amp gets - it can't go over that limit.

I guess that make sense to run the amps all the way up to prevent output spikes (I do the same usually with the master on the mixer) but haven't heard of doing so before. will this not make the amps heat up more? or will simply putting in the proper signal strength from the driverack be all I should be concerned with. It seems I'm always juggling this balance between the driverack output and the amp output and this probably plays a big role in not getting the system into its sweet spot.

so with the amp all the way up, I should adjust the output from the driverack, until I read around 55v from the outputs.

when adjusting the output is voltage affected by the dB of the outputs (for example, in the crossover menu it allows you to either boost or subtract dB from any channel H/M/L)

Bruce Weldy wrote: The limiter is set by turning your mixer up to unity with a 60hz test tone running through it. Now, put a volt meter on the outputs of the amp without the speakers being plugged in. In the limiter section of the Driverack, you lower the output until the volt meter reads the proper voltage. To test if it's correct - slam the master fader on the mixer all the way up while watching the meter. It should stay at the voltage that you set.

When you say turn the mixer up to "unity" what exactly do you mean by "unity"?

Also, I'm familiar with using Volt meters, but with a speakon out I'm less sure of where to place the prongs... just left and right sides of the output jack?


Thanks again for your help!

I'm aware of how compressors and limiters work and how they effect dynamics and hear what you're saying about not compressing electronic music which has been compressed already. However I'm fairly positive that the "overeasy" function on the driverack pa+ is on the limiters. as I understand it, it just curves the attack of the limiter to reduce the sharp cut off effect when you hit your ceiling.

My mistake, there is an over easy on compressor and limiter. You should NOT use it on the limiter. The over easy allows you to go past your limit point - that's not good. It's something you might use for the tops if you are limiting them as it might be more "musical"....but, if you are hitting the limiter, it's best to hear it and turn down.

I've been running my highpass at 35hz as per the plans, but are you saying that the extra 5hz extension is putting a great deal of excesses strain on the drivers? If so running at 40hz makes a lot more sense, does it require more voltage to output the lower frequencies?

The lower you go, the further the cone has to travel to produce the tone.... the louder you go, the further the cone has to travel. So, raising the highpass and lowering the limit some will protect your drivers better.

I guess that make sense to run the amps all the way up to prevent output spikes (I do the same usually with the master on the mixer) but haven't heard of doing so before. will this not make the amps heat up more?

They heat up based on output.....if it's turned all the way up, but there's no signal - it won't overheat. If it's it's all the way up and you hammer the input - it will heat up and it will distort like hell. So, you want it turned up and let the input determine how much goes through the amp.

or will simply putting in the proper signal strength from the driverack be all I should be concerned with.

Yes

It seems I'm always juggling this balance between the driverack output and the amp output and this probably plays a big role in not getting the system into its sweet spot.

Yep

so with the amp all the way up, I should adjust the output from the driverack, until I read around 55v from the outputs.

No, the output of the driverack lives in the crossover section when you can adjust the gain of the highs and lows. Those should be used for getting the system balanced between the tops and subs. I occasionally have to juice the subs a little on outside gigs to keep it in balance....other wise they both stay at -0-.

The limiting is achieved by the limiter, not the outputs in the crossover.

When you say turn the mixer up to "unity" what exactly do you mean by "unity"?

Thats -0- on the fader. There's a mark on every mixer at -0-.... anything above that is + and anything below that is -.

Also, I'm familiar with using Volt meters, but with a speakon out I'm less sure of where to place the prongs... just left and right sides of the output jack?

If your amp has binding posts - use those for hooking up the meter. They are the same as the speakon. If your amp has only speakon, you'll need to build a cable. Take a piece of speaker cable a few feet long and put a speakon on one end. You'll use the bare wires on the other end to attach the volt meter. Or, just take a speakon off one of you speaker cables.

Sweet, this just really cleared up a lot for me. I had no idea overeasy allowed me to surpass my limiter... I thought it was all rounding below the ceiling. This is very likely what led to the blown drivers because I noticed the driverack showing a clip light and dialed the limiters way back but then it clipped again when a dumbass dj cranked the master on the mixer out of the blue.

One final question would be that I'm still a little iffy on exactly what is creating a varying amount of voltage going into the drivers.

I'm following you on adjusting the output from the crossover section of the driverack but then also that controlling the voltage is done solely with the limiter. If that's the case then what if having H/M/L all at 0 leads me to having a really low volume output from the cabs? At that point I figure going to the mixer and turning up the master would be the next step, but would that then lead me to having higher voltage output? If I've tuned the limiters to be correct at "unity" then wouldn't I need to then change their settings?

What I'm getting at here is how to know exactly what settings on what components in the system are creating a varying voltage output so I can get it just right and then then set the limiter.

Conceptually what I'm taking from your explaination is that by setting the master on the mixer to "unity" I've set the master to where it should be as an ideal position in order not to distort or clip which will be outputting some range of voltage yet to be determined. So, say I then read the voltage coming out of the amp and its either too high, or too low. If its too high, and then I set the limiter in place to correct it, wont the sound be terribly smashed at the current settings? If the voltage is too low, don't I want to turn it up in order to get the system up to its full potential? Is voltage completely unrelated to these dB output levels and I'm totally missing the point? ....lol thanks for you patience here.

Riflefeet wrote: I'm following you on adjusting the output from the crossover section of the driverack but then also that controlling the voltage is done solely with the limiter. If that's the case then what if having H/M/L all at 0 leads me to having a really low volume output from the cabs?

That should only happen if the amp is way underpowered to start with. That amp claims 3000 watts at 4 ohms...that's 110 volts. So, if you are putting two subs on one side and two on the other - there's more than enough power and you definitely need to limit them.

At that point I figure going to the mixer and turning up the master would be the next step, but would that then lead me to having higher voltage output? .

That's the point of the limiter - it won't allow more than the voltage you've set for it.

If I've tuned the limiters to be correct at "unity" then wouldn't I need to then change their settings?

No, you have set a limit on what comes out of the driverack. You can set it with the fader at unity or at the first yellow light on your mixer - whatever you want to be the spot that you know you are going to hit the limiter. If you go past that point, the limiter will kick in.

That's the point of testing the limiter after setting it. Set it at whatever point you want, then slam the fader all the way up into the red. If the voltage reading stays put - then the limiter is working properly.

What I'm getting at here is how to know exactly what settings on what components in the system are creating a varying voltage output so I can get it just right and then then set the limiter.

That's why you set the limiter with the fader at a point where you'll know that you are going to hit the limiter if you go any further. The other gains on the driverack are at unity and stay there (unless you need to do some massaging in order to balance the system).

Conceptually what I'm taking from your explaination is that by setting the master on the mixer to "unity" I've set the master to where it should be as an ideal position in order not to distort or clip which will be outputting some range of voltage yet to be determined. So, say I then read the voltage coming out of the amp and its either too high, or too low. If its too high, and then I set the limiter in place to correct it, wont the sound be terribly smashed at the current settings?

The only way it will be too low is if the amp isn't powerful enough to get up to 60 volts - since we know it will do 110 volts, the point is moot. If you ever switch to an amp that can't get up to your voltage, then buy a new amp.

No, the sound will not be smashed unless you exceed the voltage - and if you do exceed the voltage, that EXACTLY what you want it to do......that's the point of the limiter - keep you from blowing up your drivers. So, you can either have the system sound absolutely great right up to the minute that it explodes, or you clamp it down, hear the limiter kicking in, then turn it down....thus saving the speakers.

If the voltage is too low, don't I want to turn it up in order to get the system up to its full potential? Is voltage completely unrelated to these dB output levels and I'm totally missing the point? ....lol thanks for you patience her

See above on the issue of too low......your system is at it's full potential when the limiter is engaged. It sounds like you are confusing a limiter with a compressor and you think it's on all the time pumping and breathing like a compressor does if hit too often......the limiter (if set correctly - NOT using that Easy Over function) only engages when you hit the wall....it is essentially off until you hit the limit.

Hope that helps.

Bruce Weldy wrote:
Hope that helps.

massively. thank you!

I think that your amp is too small for all 8 T48s because the specs are inflated.

Lifted from a forum:
Behringer:
1.37kW into 8 Ohms, 2.05kW into 4 Ohms for full-range or mid-top duty
1.16kW into 8 Ohms, 1.80kW into 4 Ohms for Bass duty


......from this thread: http://forum.speakerplans.com/behringer ... 69202.html


You may be able to get the proper voltage but the amplifier will not supply enough current. (volts x amps = watts)

Tom Smit wrote:I think that your amp is too small for all 8 T48s because the specs are inflated.

Lifted from a forum:
Behringer:
1.37kW into 8 Ohms, 2.05kW into 4 Ohms for full-range or mid-top duty
1.16kW into 8 Ohms, 1.80kW into 4 Ohms for Bass duty


......from this thread: http://forum.speakerplans.com/behringer ... 69202.html


You may be able to get the proper voltage but the amplifier will not supply enough current. (volts x amps = watts)

Oh geez.....can't believe I missed this.....I thought there were only 4 subs. The iNuke6000 is a two channel amp and is not 2ohm capable. There shouldn't be more than 4 total subs on it. Two per side.

The iNuke NU4-6000 is a 4 channel amp that could handle all 8, but would be short on power to run it to the limit of the 3015LF...(most likely based on their published 2 ohm rating).