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[Samuel Rees]

I'm going to set it up as discussed and experiment a bit. Clarification of my last 2 questions would be awesome thoughts

I'll bring this post up this weekend when I work on this rig again. I've got some other troubleshooting to do with other gear, cables, drivers and etc as well. Thanks everyone!

[AllenDeneau]

I'm going to set it up as discussed and experiment a bit. Clarification of my last 2 questions would be awesome thoughts

Hi Samuel, I simply use the pass band output gain attenuators to fine tune after all others parameters are set. If after everything is done and I still seem like one pass band or another isn't "in line" I'll adjust within the DSP on the output gain.

I'm still learning how to maximize the use of DSP and as I've said before, my way isn't necessarily the best, or even right, but it's how I was taught.

As far as gain knobs being accidentally adjusted you can cover them with security panels since you won't be adjusting them anyway.. My thought is, if someone adjusts the gain knobs on the amps, you'll know, especially if you're loud enough to be near or in the limiters. If you're playing background music, you may not and it won't matter as much anyway, but at "show" volumes, I'd suspect you'll notice a difference, especially if it's only 1 knob.

As weird as it is to say, I don't know much about the Crowns as I've never used them... But for easy identification, you can use a paint pen or nail polish or anything to "mark" the knob location to easily verify at any time.

To be honest, I was taught to set all amps to the same voltage gain setting but Matthews suggestion is a possibility as well. Here's another PSW thread that may shed some light on the attenuation question: http://forums.prosoundweb.com/index.php?topic=1864.0

Here's another article with a bit more depth: http://www.prosoundweb.com/article/print/straightforward_approach_to_setting_an_optimized_audio_system_gain_structur

Hope that helps...

[Matthew Knischewsky]

That said what calculations should I be running to configure the attenuators (as trim in DR)?:

1) For the QSC I can pull it back to match the sensitivity to the Macro-Techs. Seems like I understand how to do that so, check.

Do you have the suggested tunings from JBL? I looked and could only find 4732a and 4732x. the X version is probably closest but both lack settings for the tweeter. So let's those settings as an example:
http://www.jblpro.com/BackOffice/ProductAttachments/srx_dsc260.pdf
since you're using a modern processor instead of the JBL DSC260 I would bring the gain settings closer to zero :Sub +1, Low 0, High -10.5. If you run all of the amps at 26dB sensitivity then those are the numbers to plug into the drive rack.

I also looked up the gain settings in dB for the crowns in their respective manual:
Macrotech 1200 @1.4v = 31dB
macro tech 2402 @1.4v = 33dB (2400 is the same)
macro tech 3600vz @1.4 = 36.8 dB
Macrotech 5002vz @1.4 = 37db

So if you used a 3600 for Sub, 2402 for LF, and 1200 for HF your settings would be Sub -2.8, LF 0, HF -8.5. All I'm doing is compensating for the gain or attenuation applied by the amplifier when running in 1.4v mode. I used the middle band pass (in this case the LF) as the reference and compensated for the HF amp which is 2dB less sensitive and the Sub amp which is 3.8dB more sensitive. In general when system tuning I like to keep the midrange band pass is at 0 in the processor. If you're planning to use the 3600 on LF, the 2400 on HF and the QSC 1500 on VHF here's your settings:
LF: 0
HF: -6.7
VHF Unknown.

2) Power handling on drivers. Should I be using just limiters in the DR to account for the fact that the amps are a little overpowered, or is there additional attenuation I can do to consider this?

Ivan Beaver has some good posts about setting limiters. I don't have time to get into the specifics but the best way is to calculate whet the amp's output voltage should be for the driver's wattage and impedance ratings, then use a load bank to make the settings. Your amps are probably really close to where they should be power wise, overpowering by 1.5 to 2 times is generally accepted.

Matt

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