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Powered speakers - gain structure question

bcahillbcahill Posts: 3
edited October 2007 in PA General Discussion
Thank you for this forum.

I need help setting the gain structure with the DPA and powered speakers. I have read the “Start here�, “FAQ’s� on this forum and Chuck McGregor’s white paper at PSW Study Hall.

Mixing console:
Allen & Heath GL2200-32channel

1 - dbx DriveRack PA (w/UPS battery backup)
2 – Alesis MidiVerb4
2 – dbx 266XL Compressor/Gate
6 – dbx 31 Band, 1/3 octave EQ’s
4 for monitor mix
2 for FOH
2 – Crown CE2000 Amps for monitors
3 – Furman Power Conditioners

Speakers FOH:
2 or 4 Mackie SA1232 Powered 3 way
-3 dB - 45 Hz-18kHz
-10 dB – 38Hz-20kHz
Crossover: 24dB octave at 700Hz and 3kHz
Sensitivity 103 dB 1W@1m
Max SPL long-term 130dB
Max SPL Peak 136 dB
HF 100 watts
MF 100 watts
LF 1100 watts

2 Mackie SWA 1801 Powered subs
-3dB – 45Hz-120Hz
-10dB – 35Hz-120Hz
Crossover: 12dB octave at 120Hz
Max SPL long-term 129dB
Max SPL Peak 135 dB
900 Watts continuous
1,200 Watts peak

Speakers Monitors:
8 - Peavey TLM5X
2 – Peavey TLM2
2 - HotSpot


I have set the System Set-Up for 2 X 4 configuration with everything custom.
Input-Stereo
GEQ-Stereo Linked
Main PA-Custom Passive
Subs-Custom Stereo
High Amplifier-Custom
Low Amplifier-Custom

XOVER
L
HP @ 45Hz BW24
LP @118Hz BW12
0.0dB
H
HP @ 118Hz BW12
0.0dB
This is where my cabinet’s crossover at factory specs. 120dB 12 octave. See equipment list.

I have been using the DPA for 2-3 years and am reasonably familiar with it. Since I found this forum I am much more comfortable with it. I believe I have read almost every post and some several times.

I have used the auto EQ Wizard in small rooms and bars and large ballrooms. I have even taken it out in a parking lot in a commercial area and played with it and run the Auto EQ Wizard. This was before I knew not to trust frequencies outside of 170 – 700Hz. Now that I have a little more knowledge I am going to set up again in the parking lot before the weather turns cold.

Now back to my question. My understanding is with powered speakers I need to go through the same procedure I would with non-powered speakers and find the clipping point and back off just a little bit. I can do this outside in a parking lot with pink noise at night. I just want to make sure I do it correctly this time because it is a lot of trouble to set up and tear down. The last time I was able to get the speakers to indicate clipping with a Phil Collins CD. At the time I was more interested in EQ’ing the speakers flat than adjusting the gain structure. I had already run the Auto EQ Wizard and had some time to drink a beer and play.

While I am set up and have some time what else should I test, check, adjust, set, limit, etc. in the DPA? I plan to EQ the speakers as flat as I can and save the setting. Can I set the DPA limiters with powered speakers and accomplish the same thing as having separate amplifiers and speakers? The Mackie’s have built in protection. I have the Blink Test CD and have used it to check some rooms as best I am able to with my ears. I also have a Phonic PAA3 RTA that I am learning to use and to help me troubleshoot some of the more difficult rooms. This has let me see the changes I have made in the PEQ in the DPA and to understand the functions more clearly.

We are a 9-piece band, over 50, with 3 horns, guitar, bass, keys, drums, percussion, lead vox, and me mixing FOH and monitors. Our music is 60’s, 70’s,and 80’s rock, Motown, and disco. We are weekend warriors and play in everything from 1,000 sq. ft. bars to 20, 000 sq. ft. ballrooms.

Thanks in advance for your help. This forum has answered many questions I have had about the DPA. When I have this problem solved I have a question about the delay.

Brian

Comments

  • Options
    DraDra Posts: 3,777
    My experience is that powered speakers typically work best in the 11 to 1 o'clock range. You are pretty much stuck with using the limiters in the speakers.

    I also recommend not using the DBX GEQ's and only use the EQ in the DRPA. You could find a good home for the 2 EQ's inserting them, either for feedback issues for vocals or possibly for tonal issues of your kick drum or some other instrament. Now if you only are using the DBX EQ's as a \"quick pull down\" devise, I guess that's OK.

    For the delay, just step through the settings 0 - 10 msec and when the bass gets tightest, you're there.

    If I might...
    consider changing the top to sub x-over point to 100 hz with LR 24 slope.
    Also change the 45 hz BW 24 to BW 18.

    DRA
  • Options
    DRA,

    Thanks for the reply.

    I also recommend not using the DBX GEQ's and only use the EQ in the DRPA.

    The DBX EQ's stay flat and are for quick fixes now that I understand the DRPA better. I also believe that the DRPA PEQ's are to be used to flatten the speakers and the settings stored while the GEQ's are to be used to adjust for each venue/room as necessary. Is this correct or do I have it backwards?

    consider changing the top to sub x-over point to 100 hz with LR 24 slope.

    May I respectfully ask why? I figured that Mackie had done some pretty extensive testing to come up with that number. I am always open to suggestions and will try almost anything once or twice. I will try it next time I set up the system and see if I can can tell a difference. What exactly should I be listening/looking for?

    Also change the 45 hz BW 24 to BW 18.

    Done.

    For the delay, just step through the settings 0 - 10 msec and when the bass gets tightest, you're there.

    Will also do this the the next time the system is set up. Is this setting a constant for the cabinets or is it a variable for each room? If I understand correctly this is cabinet specific and an additional delay is necessary to bring drums in time with the PA.

    Thanks again for your help.

    Brian
  • Options
    DraDra Posts: 3,777
    GEQ / PEQ - you are correct.

    X-over change - You actually have more power available in your top cabs than our subs. So this will give you a tad more available power in your subs. A good test is hook up the subs only and play some good full spectrum music then the filter at 200 hz or so then sweep it down until the \"trash\" goes away. By all means, try it both ways and go with what sounds best.

    Delay - Your tops components should be \"time aligned\" for itself. The subs will need to have the tops aligned to them. For horn loaded subs the sound has to travel the contour of the horn before it exits, so the tops have to be delayed to \"wait\" for this travel. Physical placement can be used to match this delay, but sometimes is not practical or quickly done. The room in general does not affect time, so if you stack your speakers exactly the same every time, then you should not have to fool with the delay.
    DRA
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