Home dbx User Forum dbx Archive Threads DriveRack PX

QSC + PX, application specific from soon-to-be owner...

KentOnDrumsKentOnDrums Posts: 30
edited September 2012 in DriveRack PX
Please be kind, I’m the drummer / most technical in the group, so I’m doing the best I can…

I play in several bands in a large community. We play several times a month to crowds of 165 – 170 people (mostly dances). My newest group – and possibly best musically – does not want to use our normal sound man (who is extremely good), so the lead singer / keyboard man will be running sound from the stage.

We did our first gig – sans sound man – a couple weeks ago. While the crowd loved the performance, feedback was a problem (at a very high frequency), thus I just ordered a PX from Musician’s Friend due to arrive any day now.

Given I’m the drummer / lead guy for sound, my goals are modest:

- Eliminate feedback
- Get good to adequate sound
- Keep setup time to a minimum, like maybe 15 minutes on the PX?

What follows is an overview if our specific situation along with application specific questions. Any answers or tips you can provide are greatly appreciated.

Equipment

(2) QSC K-10s
(1) QSC K-Sub
Yamaha MX Series Passive Mixer
[I will probably start doing a sub-mix for drums via a small Alesis passive mixer, fed mono to Yamaha]
DBX PX
Several powered monitors: Small Yamahas, Behringer and one QSC K10

Room

• 30’ x 90’ (Ceiling: Not sure, but maybe 15+’)
• Play on temporary stage from middle of long wall, facing the short distance
• Hardwood floor
• Glass on back wall (10’?), and partial glass (20 percent) on one side – glass covered by blackout shades
• Dance floor in center (in front of stage), tables holding about 160 – 170 people split on either side of dance floor

Music

Moderate volume
Genres range from Crooners like Frank Sinatra, to Motown & oldies Rock ‘n Roll

Setup

• 4-piece band on stage
• Keyboard player (lead vocalist) does mixing
• Myself (the drummer) sets up most of the sound gear
• Speakers placed on back corners of 16’ wide by 12’ deep stage (admittedly, an unconventional setup) – placement driven by leader’s desire to hear what the crowd hears via the mains
• Sub normally under one speaker placed by my drum kit so I can hear my kick
• Because of wall-cabinets / room shape, etc., speakers are approximately 4 to 5 feet from back wall
• Fabric backdrop behind band
• Speakers set “square� to back wall (ie no toe-in/out). We’ve used this config before, the crowd loved our performance, but naturally feedback – especially at a very high frequency – was a problem when singers stepped away from their mics. Friends in the audience reported sound quality from good to ok, but obviously feedback was the major gremlin in this set up.
• Carpets on the stage

Wiring Configuration

• Plan to run mono FOH via K-10s in series and use second channel to run powered monitors via Aux-out (so the PX will eliminate feedback from both). Sub to be run in mono from PX Left sub out.

MY CUSTOM SET UP PROCEDURE

STEP 1 – Quickstart Page 2-6

1. Wire electronics / speakers
2. Use Wizard to select our QSC configuration

Question: We plan to run the PX in stereo, with left being FOH and right being monitors. Does this change RTA?

Question: We will be running mono, with speakers behind the band, and close to each other (mono). Should RTA mic be placed as specified – 25� in front of speakers and centered on both speakers? What about monitors?

STEP 2 – Run the RTA pink noise process to EQ system to the room as defined in pages 7-9 of the quick reference guide.

STEP 3 – Following Quick Start pages 7-13, set AFS wizard to have 6 preset and 6 live settings to control feedback.

Question: Again with one channel for FOH and the other for monitors, will this work?

Comments and suggestions welcomed. Thank you in advance. Kent the drummer and part-time sound man (I do posters and promo too!).

Comments

  • DraDra Posts: 3,777
    Welcome!

    If you plan to run FOH and monitors through the PX, you can not have separate EQs. You are asking for problems there. You'll need to step up to the DRPA (used) or DRPA+ to be able to do that. Of course the 260 also fits the bill for more $.

    I don't quite get how having the mains firing through the stage (for the leader to hear FOH) does any good if you are also going to have a monitor mix. That skews the heard results. Seems that to get the resulting benefit of being able to hear the FOH that he could just have a "FOH monitor" at his position and move the mains to where they should be, out front.

    Auto EQ - Be very careful with it's use. Read everything you can in the forum about the pitfalls and assumptions that can wreck your sound.

    Your current set-up is not unique, but your results are typical. It requires a lot of concessions to implement. You mentioned nothing about currently used EQs for house or monitors.

    You implied that the feedback problem is in the FOH speakers. Do you also have any in the monitors?


    DRA

    Edit - Tear out the page in the manual regarding using the Auto-EQ function / mic. Use the method(s) described here. Search and read... then read some more. Also, tear out the page about setting up the gain structure.
  • Thank you Dra. Your note on not doing monitors and FOA as stereo channels is a huge discovery, so this forum has already been a big help to me. I will answer your other questions when I have more time. Thanks, thanks, thanks! Kent
  • DraDra Posts: 3,777
    FYI.
    The PX is MARKETED to powered speakers. It works and fills a niche, but it is business driven. All platforms of the Driverack line can be used for powered or passive systems... hence the PX is MARKETED to you, but is nothing more than a scaled down version of the PA (+). DBX believes that since you bought powered speakers you wouldn't consider buying a more advanced model, so they created the PX to suck you in... because" it is for powered speakers".

    DRA
  • Thanks Dra...

    Yes, I know mains belong out front. But the musical lead for this group (who is an extremely good singer / entertainer) wants it this way. And so it shall be.

    Monitors

    1. In lieu of dedicated keyboard monitor
    2. Option to boost vocals for front line (likely used in moderation)
    3. For me on back line (drums), mostly to hear guitar and keys

    Thanks for the heads up on Auto EQ. I'll do more reading.

    Current EQ

    I play this venue with four different bands. Three use a very good sound man with a snake / Presonus digital mixer. So I don't know what he does for settings.

    The group in question here, is new. First time out we used my regular sound guy, but he had the date mixed up, showed up late and things did not go well on stage. So for our second performance we did it the way the musical lead wanted -- speakers behind the band, and no sound man. In terms of EQ, very little was done for this second performance.

    Feedback from Monitors vs Mains

    Due to room availability, we only have 30 minutes for soundcheck. Even so, we thought things were OK. But after walking away from the mics, a minute or so later a very high frequency noise started. Turns out as long as vocalist were in front of their mics, no feedback. But when they moved their head away from mic for more than a few seconds, the very high frequency feedback came back. Monitors were not real loud, so I assume the feedback was caused by mains.

    PX is MARKETED to powered speakers

    Is the setup speaker wizard BS, or does it help? Given our limited time for soundcheck, if the wizard does more good than bad, this is a plus.

    From the first round of comments, I have more homework to do on auto-EQ, and the PX will be dedicated to FOH.

    Assuming the set up wizard is a plus, I will use this too.

    Thank you again! Kent
  • DraDra Posts: 3,777
    I don't own a PX, so can't speak to the filter settings for given set-up,but in the other platforms they are totally generic and many times are just wrong. Not damage wrong, just not as good as they should be. Maybe Gadget can pipe in for the accuracy of plug-n-play.

    DRA
  • …Ok, I’ve now read a lot about Auto-EQ. I had skimmed many of these posts prior to registering, but this time I read them carefully and looked up the meaning of unknown acronyms.

    Looking at Gadget’s newer Indoor Auto-EQ method seems like a good way to get the PX and QSC mains in sync, at least for basic EQ.

    One of my small bedrooms has been converted to a dedicated listening room, with many bass traps, front wall floor-to-ceiling, tri-corner traps, etc. So even though the room is small, reflected sound is tame for an indoor space.

    Question: Gadget uses a piece of plywood below the mic. Given this is emulating a PZM setup, I assume plywood or particle board is better than a carpeted floor?

    Thanks for all of the help. The UPS man just dropped off the box, so the fun begins!
  • GadgetGadget Posts: 4,915
    The picture is misleading and we have found that lying the mic ON the carpet or a towel works better, that pic was because I didn't have a short stand at the time...
Sign In or Register to comment.