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RTA Mic and Pink Noise Volume

mgh1196mgh1196 Posts: 4
edited December 2015 in DriveRack PX
I have been unable to get the Auto EQ to give the "performance level" message and move to the next step. I have done the method in the manuel, the outside method, and the new inside method. I have set the speakers (JBL Eon15/with two Eon subs run mono) to different levels and cannot get a RTA reading no matter what I do. Have gone all the way up to the point to where the guy who owns the speakers has ordered me to shut it down. Yes the RTA button is engaged. How load does it have to be to get it to work???????
Thanks,
Mike

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    GadgetGadget Posts: 4,915
    DRPA, or PX?
    1. Enter Wizard, select "Auto eq"
    2. Follow the prompts..."press the mic button next to the mic input to enter the Auto eq sequence...
    3. turn the rotory encoder clockwise to set the desired level (LOUD)
    4. if you cannot get the Auto eq to indicate "TURN DOWN LEVEL" you need to check the mic cable...
    5. once the desired level is set, press the [next] button and the sequence will begin
    have you experienced this?
    G
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    mgh1196mgh1196 Posts: 4
    It is the PX.....
    I have done all you have said.... entered the wizard, followed the prompts, pushed the RTA button, used two different RTA mics, different cables and still have not experienced a "turn down level" message and have not been able to proceed with the sequence.
    The manuel says, "0db-6db typical," the picture in the manuel shows 18db, and I have turned mine up to 20db. REALLY load! Will this high volume of pink noise damage the speakers? Should it need to be this load? What is TOO load?
    Thanks for your help,
    M
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    DraDra Posts: 3,777
    Pink noise definately can kill drivers (especially horns) and x-over components.
    As far as "how loud"? Just like the manual recommends... 0-6 is plenty (I've done much less).
    2 RTA mics? What are they? Are they condensors? Do they work (when spoken into)?

    DRA
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    GadgetGadget Posts: 4,915
    Definitely don't exceed the amps clip point of the amps! Try and get an assumed parity with the system volume you will be using for shows.
    G
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    mgh1196mgh1196 Posts: 4
    The two mics are the one that came with the PX and the dbx one that I ordered. When setting up for an outside gig the original mic stand fell over onto concrete with the mic in it. OUCH! Couldn't get a reading so thought maybe the fall damaged it. Ordered a replacement (another dbx RTA) and got the same result, no reading....
    Maybe the PX itself is not working properly cause I have tried multiple variations of mic placement and volumes with no success. ????????????
    Will give it another go and if nothing happens will return unit for exchange.
    Thanks again,,,,
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    DennisDennis Posts: 801
    Did you try plugging your two mics into your mixer, engaging phantom power, and speaking into the mics just to see if they worked?

    Dennis
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    markfer6markfer6 Posts: 3
    I just purchased a driverack px via ebay and am experiencing the exact same problem Mike posted here. When running the setup wizard, and playing pink noise through the speakers, I can't get the DR to get to the "set to performance level" no matter how loud I turn the pink noise up. I've had it much louder than the intended playing volume with still no result. I've checked the RTA mic and it is working. I noticed there was no solution posted to Mike's problem way back in '09. Anyone have an answer?
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    DraDra Posts: 3,777
    Without his follow-up, we really can't know.

    He has an e-mail link. If it has not changed you might try that to see what the conclusion was.

    DRA

    A thought. Could be that the mic input is not passing phantom power. You might check that. How much did you pay for the PX? If cheap enough a repair may still be warrented. Is it returnable?
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    markfer6markfer6 Posts: 3
    Thanks Dra,
    I did send an email to Mike. As far as the mic input not passing phantom power, you are referring to the driverack mic input right? How could I check to see if it's passing phantom power?
    Mark
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    GadgetGadget Posts: 4,915
    Did you press the >next button to engage the Auto EQ mode?
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    markfer6markfer6 Posts: 3
    Yep, I did press the next button.
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    DraDra Posts: 3,777
    markfer6 wrote:
    Thanks Dra,
    you are referring to the driverack mic input right? How could I check to see if it's passing phantom power?
    Mark

    Yes.
    You'll need a volt meter.
    This is from Shure. Is should be useful. The voltage may be different, just make sure that the voltage meets the minimum required to operate the mic. DBX specs 9-52 vdc.




    QUESTION:


    I have a Shure MX392 that works OK on one input of a mixer, but not on another input of the same mixer. I suspect the phantom power supply of the mixer, or the mic cable run that leads to the mixer. How do I test the phantom power voltage and current?






    ANSWER:


    For this example, we will assume the phantom power voltage is rated at 48 Vdc and the maximum phantom power current is rated at 7 mA, i.e., 48 Vdc supplied through a 6.8 kOhm resistor as per the DIN Specifcation 45 595, dated August 31, 1976.



    First, measure the phantom power voltage:
    1.Disconnect the mic cable from the mixer.
    2.Set the Volt/Ohm/Amp meter to read from 0 to 50 volts DC.
    3.Measure from XLR pin 2 to XLR pin 1. Note the voltage.
    4.Measure from XLR pin 3 to XLR pin 1. Note the voltage. The DC voltages measured should be exactly the same - to the tenth of a volt.
    5.Measure from pin 2 to pin 3. The DC voltage should be zero or nearly zero.
    6.Reconnect the mic cable and make the same measurements at the microphone location, BUT with the microphone disconnected. The voltage results should be nearly identical to the readings at the mixer.

    Second, measure the phantom power current:
    1.Make these measurements at the microphone location, but with the microphone disconnected.
    2.Set the Volt/Ohm/Amp meter to read from 0 to 100mA DC.
    3.Measure current by connecting the positive meter lead to XLR pin 2 and the negative lead to XLR pin 1. The reading should be > 7mA.
    4.Repeat the previous step using XLR pin 3 and XLR pin 1. The reading should be > 7mA.

    If the voltage measurements and current measurements are not as described above, the mic cabling could be defective or the phantom power supply circuit in the mixer could be defective. In either case, the phantom powered microphone will not operate properly.



    If screw terminals are used:

    XLR pin 1 = ground

    XLR pin 2 = audio positive/send

    XLR pin 3 = audio negative/return

    DRA

    PS - please report back any and all info regarding the solution to your problem.
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    Krazy BKrazy B Posts: 51
    I dont need to do teh Auto EQ much these days as my regular venues are now stored. BUt the last time I used the auto EQ mode, I found I was not registering any response from tthe TRA mic.

    By plugging the RTA Mic into my mixer with the same lead I was using for the Auto EQ Wizard and applying power feed to the relavent channel, I quickly proved the RTA mic was OK by simply talking into it.

    I then went back to the PX rack and started the the Auto EQ wizard again with no response from the MIc again.

    However by pushing the RTA mic plug a little more firmly into the PX Rack RTA socket I was then able to complete the wizard. So I suspect a little wear and tear is the issue.
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