Home dbx User Forum dbx Archive Threads DriverRack PA & DriveRack PA+ PA General Discussion

DRA's Super Duper Limiter Procedure

maddogmaddog Posts: 21
edited February 2010 in PA General Discussion
I PM'd DRA about his procedure and had a few questions, he thought it may be helpful to post it in case someone has the same issue. Not that theirs loop holes in his article, but maybe a few things beginners may overlook. You'll see that my MAIN ISSUE was the mixer was just to hot going out, and a few other things I had to learn and figure out. If you have not read the START HERE post I must say you should, great info and the following are questions I had after reading that thread, and a set up attempt.

maddog
I must be missing something but I can adjust the threshold on the drpa+ and the amps stop clipping but the TH on the drpa+ is still reading red all the time. I have the pink noise going through the yamaha mg 2414fx and has the pfl and afl so everything is up to par.
guess I'm just missing something or is that normal? :?
I guess i better clarify at this point, forgot that you don't even know what the heck I got going on, I am setting up a smaller system for smaller places.
At this point it's;
2x3 system
jbl jrx 115 mains with crown xls 802 stereo
jbl jrx 118 subs with carvin dcm 2500 stereo, parallel input from drpa+.
Under powered but don't need much here.

I have the TH red lights flickering at this point on the limiter section.

Highs limiter on- over easy 1- thesh 7db- 802 at about 1 o'clock.
Lows limiter on- over easy 2- thresh 15bd and the dcm2500 at about 10 o'clock
Maybe this is OK but I don't know and asking a pro.
So far the lows are what I had to turn down more after initial gain structure, they were at about 2 o'clock before setting limiters, guess I'm confused again.

Thanks Dra for helping all us analogers find the digital world slowly.



Dra
That means that you are beyond the threshold. I'll assume that your mixer is in or near red line.
Let's back up a bit.
After setting the gain structure, so that everything clips at the same time (and the amps dialed back to stop clipping), you'll have the "non-limited" max position for the amp.
Then do the limiter set-up (with amp back at the barely clipping point), after which you'll return the amp to the non-limited setting.
Now, balance the system by turning down the louder amp(s) while playing music.

If the limiters on the DRPA are engaging, the input is too high for the output you are trying to achieve.


maddog
I'm using my laptop out to the rca input of stereo channel 23/24. The gain nob has to be up to about 9 before channel clipping starts, then i backed it down to about 6. The channel and the main faders are at unity and the meters are a strong yellow almost in the red, Maybe that's the problem (high). I have to pull the master down to about 30 before the low TH lights go off on the drpa.

I'm confused here and cant find where it is on the drpa.
9. With the DriveWare GUI open the DriveRack panel meter and then one of the mixer input dialogs (click on the \"M\")........................
10. Click on the other channel’s mixer input dialog (click on the “M�), set the master fader at “unity� and put the input fader at the very same location as the previous channel.

How do I open the DriveWare GUI?


Dra
From your laptop...
what sound source are you sending to the input channel of the mixer?

The GUI is not available for the DRPA.


maddog
Track 58 pink noise 20 min. running it through media player with volume up all the way.
Laptop volume at about 7 through the headphone jack.
Input gain at 6. unity on channel and main. Now I adjusted the input volume from before so the meters are not so close to the red. Here is what I have so far at the drpa.
High over easy 3... thresh 6 db
Low 3 14db
Thats the point I could get the TH limiters out of the red and the amps are now up to 3 o'clock on both.
Where should I be shooting for on the limiters?


Dra
You want to be sending -0- to the masters. PFL the channel and turn the input gain up until the master meters are -0-. Leave it. (Though that channel gain is set ONLY for this source and will change for different sources, like mics, or DI's.)
Now, turn off the PFL and bring the input channel fader to -0-. Bring the master fader up to -0-.
The meters should read -0- also.
Bring the MASTER faders (only) up to your max / clip / red line point.
The input meters on the DRPA should not be hitting +20 at all. If they are, the will have to use self control and NEVER run your mixer that hot. If this is the case you'll need to see where the mixer is when +15 on the DRPA is just less than solid lit.
What to shoot for on the limiters?
The amps not clipping when board is. Bearing in mind that the DRPA is not brick wall and will pass signal. For example, if the mixer sends a +18 signal and the DRPA is set to limit starting at +16, then 2db will (depending on the ratio and knee) squash the extra 2db, But if the mixer is pushed more and sends a +20 db signal, then the DRPA will only grab 2db but allow the other 2db thru, allowing +18 on to the amps... and so on. More limiting offers more protection, but may not give you the volume you need, or may kill your dynamics, or both. If this is the case you need more rig, or you have to run your rig MORE to the edge. As you see, there are trade=offs, when talking limiters.


maddog
Thanks
Your last mail summed it up good and a light bulb popped up over my head, so I have that done and every things looking good now. :D
On to a another simple question that I have not read about anywhere. The drpa+ manual sais this;
"You can also use the full time RTA feature to monitor levels and make adjustments yourself."
Can you point me in the right direction for that.

Thank you for your help.


Dra
Glad to help. I have a 260 and DRPA's, but no +, so I can't help with the RTA question.
Since we actually solved your "disconnect" AND because others can learn from our back and forth, it would be a good idea to copy this PM and post it as a topic in the forum. Then Gadget can help you with the RTA.

Comments

  • GadgetGadget Posts: 4,915
    Dra old Buddie I took the liberty of modifying your response a bit.. I took out the word "UN" limited, since that could be "misconstrued" as meaning "other things".. and replaced it with "non" limited indicating that we were NOT limiting (unlimited can mean we have MORE than we need)

    As for the "realtime" RTA .. it is the exact same as the 260. It gives you the ability to look at whatever the mic is "seeing" in the position it's in. Including all the reflections that arrive at different degrees of out of phase paths up to and including totally out of phase... which means it is completely inaudible (silent) to the mic! move the mic a few inches and what WAS out of phase is back in and something TOTALLY different is now totally silent. This happens for EVERY different location you pick in the room over (EXCEPT) when the mic is used in PZM fashion. (as in the "new indoor method, and " Auto eq, how it's supposed to work") from the FAQ section, and where the patterns either intersect, or have completely separate paths... I got very predictable results as posted in the "how it's supposed to work", and the "new indoor method".

    Put the mic on a stand and place it "oh lets see ... how a bout here"... and you add CHAOS to the equation. (We're thinking " We need to eliminate the reflected energy...
    G
Sign In or Register to comment.