PX and EV force iE speakers

tp3366

I am a newbie. spent a lot of time reading your posts. But still need some guidance.

We recently bought a DRPX. Intention was to get better EQ, avoid feedback (we pass a wireless mic among the audience sometimes) and use compression when occasional spirited preachers blare out. Our 2 speakers are EV Force iE passive (15"woofer and horn) driven through a Samson 2400 amp. No Subs on the main system. A bass guitarist may be added in the future and we are thinking of giving him a separate sub/amp.

Our hall is about 40' wide 100 long and 10 feet high, but we use only half of it toward one end.

I am totally lost trying to set the PX.:
1.AUTO EQ:
First I tried to follow the guideline in the dbx quick guide keeping the RTA mic about 25' in the middle of the speakers, but even after increasing the levels to a ear blasting level the auto EQ did not work.
I saw your instructions of keeping the RTA mic very close to the speakers to do auto EQ. Is that what I should do? keeping the mic pointed to the floor? Should I do that for both speakers or one will do since both are of the same model?
2. Compression:
How can I use PX to turn compression ON/OFF as and when I need it? (depending on who speaks the day and whether his levels are too dynamic to adjust with the faders?
3. Speakers:
Which equivalent speaker should I use for EV Force iE ?( if I use custom, is there anything I have to set?)
4. How to set AFS:
I know that my questions may sound dump :oops: to you. Please help me out.

Thanks Tom

Gadget

Hi Tom,

If your familiar with Douglas Adams books you know the best thing to do in any situation is "Don't Panic!"

Sorry.. attempt at levity there...

Ok, lets get started...

1.AUTO EQ:
First I tried to follow the guideline in the dbx quick guide keeping the RTA mic about 25' in the middle of the speakers, but even after increasing the levels to a ear blasting level the auto EQ did not work.
I saw your instructions of keeping the RTA mic very close to the speakers to do auto EQ. Is that what I should do? keeping the mic pointed to the floor? Should I do that for both speakers or one will do since both are of the same model?

First off that "Quick start" guide isn't going to be successful simply because it's not duplicate-able in most situations....New theory is that if you are running stereo, and want to measure the "whole system" then you need 2 separate sources of pink noise. One for the right channel, and one for the left...the reason is, even though you may be using the EXACT same signal in both left and right speakers...the random nature of two separate sources would help eliminate some of the multiple paths to the mic problem...

That said "Houston... we have a problem!" the DRPX generates the PINK NOISE signal, so we CAN'T use two separate sources... therefore we cannot place the mic in the center between 2 speakers and get away from the multiple paths problem. (which is, if two (and usually more) identical frequency signals arrive at the mic 90 degrees out of phase ...one direct one reflected...they will cancel...move the mic a few inches and that problem goes away, but is replaced by those of a different set of frequencies)

Second, the close method (new indoor method) is designed for flattening speaker response, but has the inherent problem of ground plane bass response, and no off axis interaction...(oh and we have modified the process too, placing the speaker on its side and the mic on the floor...) Pretty good results can be achieved by this method as long as you re-consider the response plot below 200hz (listen to it with your ears and modify to taste) and check off axis response and also determine if that needs some adjustment/compromise.

So what is the best method? The one proposed by the original engineer on the design team? Place the speaker on a stand if possible, (this gets the speaker into a free field position, where there is no HF or LF boundary interaction) place the mic far enough from the speaker to allow it's sound to develop fully.. 20-25 feet. Start with the mic STRAIT out from the speaker, with the mic on the floor (where there aren't multiple bounce paths added to the measurement mic by it being on a stand)
on a soft surface (towel, carpet...) lying down, aimed at the speaker (yes it's an omni mic, but lets not add the body of the mic and unnecessary reflected energy to the mix here).

Store that preset as ON axis...Next do the same 15-20 degrees off axis \^/ store that as OFF axis now compare the two...what needs to be done here is look for the differences...make a note of those and then, with spoken word and music, play with those frequencies to reach a happy "medium", if you will...

This should give you your best bet for a more balanced overall system... Make sure your using the FLAT response, and hi precision if your doing it with no one around (it compromises less)

2. Compression:
How can I use PX to turn compression ON/OFF as and when I need it? (depending on who speaks the day and whether his levels are too dynamic to adjust with the faders?

Compression of the whole mix can be a double edged sword....it can actually CAUSE feedback...Compression is best left to a per channel basis , on the mixer...especially in this case, where you can target a specific threshold, where soft spoken passages will be boosted and LOUD passages can be LIMITED/squashed.. (consider getting the church to spring for a Presonus studio live 16:4:2 which is a WONDERFUL miser with everything you will need to solve the problems you are having...

other than that you'll need to have the DRPX right there close to turn the compressor on and off and adjust as required from one person to the next...

3. Speakers:
Which equivalent speaker should I use for EV Force iE ?( if I use custom, is there anything I have to set?)

None, and none are needed since a preset only provides a blank slate with a HPF... and even then the HPF frequency is debatable...HOWEVER, if you have speakers that are Bi-amplified, and in the list you WILL have tunings in the preset...otherwise they are simply starting points...

I would use "custom", and set the HPF @ no lower than 50hz BW18... probably closer to 60 or 70hz...

4. How to set AFS:
I know that my questions may sound dump :oops: to you. Please help me out.

The AFS needs to be understood and the system set up properly for it to be successful...Yes it will work without anything being done but you'll be expecting more than it will likely be able to provide...

FIRST get the system FLAT as possible with the above methods...next, have ALL mics, monitors and speakers on, tuned and at "show" volume (those that will be used for the service) engage the AFS with :
Muisic = medium
Live
6 fixed and 6 roaming filters
follow the instructions.. raise the master fader/s till the first frequency sets, then the second and so forth, IF your system is properly tuned you may not get more than a few to set till the master gains a re STUPID loud/high (note even if there is no sound you KNOW that if there was music playing .. at the location the faders are.. it would be STUPID loud...

Finally, the reason the auto EQ fails is your not paying attention...NOTE, when the PX clips the input signal it will begin flashing "TURN DOWN" this means turn the pink noise DOWN it's clipping the input!

The other thing that will cause the "NOT FINISHED" indication is if more than 4 frequency bands are FULLY boosted or cut...

One other suggestion, If the channels have HPF, engage those, and TURN the LF eq knob on the vocal channels DOWN maybe even off (or slightly on maybe) this will help clarity, and LF buildup in the room...

Go to the "Start Here" thread:
viewtopic.php?f=61&t=959

Sounds like you have been trying to do your homework, but missed the obvious? This thread will take you through the setup and gain structure for your setup, but use the tips above as they have not been added to that thread as of yet...

Then note these threads:
viewforum.php?f=60

For a subject by subject more in depth coverage of issues...

Gadget