And yes, stick with an iron-based amplifier rather than a switch mode supply if you're on a generator. Unless you can spring for one that costs $4k
. If for no other reason than they are repairable if a surge does take it out. Class D on a 60 Hz toroid transformer would be nice from a current draw standpoint, but I don't think anybody makes those anymore.
"Construction grade" generators can be nasty, but good generators can provide equal or better quality AC than grid power.
Be aware that a good many EDM selections have LF content with only 3 dB crest factor (same as a sine wave). Although the B&C 18TBW100 has no problem with 3000+ watt peaks, you should limit the long term average to no more than 55-57 volts (750-800 watts at 4 ohms) to insure desert survival.
Art
I have a nice big toroid transformer from a scrapped Yamaha P2200 if you want to play around :^).
Would it make sense than to run a single FR2500 in each channel on a KS (about 750watts) or did I just defeat any headroom advantage?
You would be leaving about 5 dB of headroom behind (unless you only play droning bass lines with no kick), the subs will sound anemic by comparison. You would be more likely to clip the amp, and a clipped sine wave starts looking like a square wave, which has double the average power of a sine wave, burning sub at burning man.
For EDM you need DSP with both peak and RMS limiting (attack time set to about 200-800 milliseconds), the amp limiter alone won't "get er done". Besides, you want to have the delay and EQ the DSP has.
The DCX2496 ULTRADRIVE PRO from Behringer has great bang for the buck, and can do everything you need done, other than explain how to do it ;^).
I recommend buying it new so you have a warranty. Plug it in and run it as soon as you get it to make sure it is all working, leave it on for a week or so, and cycle it on off frequently during that time.
Cannot express enough to you the value of all your advice.
My goal at the end of the day is simple, help them create an unforgettable experience with all their DJ's.
It's been a long time since I have done anything worthwhile and I am excited to be able to contribute to them, but if I end up succeeding it's a result of your time and effort. (all of you).
I thank you.
Do yourself a favor and get familiar with that generator and how you are going to hookup. You may need subpanel/twistlocks/etc. Helped out at a school fundraiser (hey can you help us setup for a few beers) gig and I had to setup the generator from 3 phase to 220V and dial in voltage (thank God I brought a meter) then only 1 vendor had correct hookups.
So it's ordered, will be here next week.
Huge noob question. I assume the 8ms delay for the mains is based on the baffles also being on the same plane? If the mains are further back/forward this would effect the proper delay amount correct? If so, am I going to need some sort of RTA up there to properly set it up?
1) 8ms is roughly the path length of the horn. Without knowing the phase response of your top cabinets I can't give you an exact delay.
2) Yes, though if you are crossing at 100 Hz the top cabinet can be moved about 34 inches forward or back and still be within 1/4 wavelength. If the output of the two cabinets are within 1/4 wavelength they combine pretty much the same as if they are perfectly time aligned.
3) Yes, or REW (freeware) and a test mic and whatever interface needed for your computer.
If you really want to go basic, set both top & sub cabinet on the ground outdoors well away from any large objects, place a microphone laying on the ground about 2 meters in front equidistant from both. Plug the mic in to a channel of your mixer, send a 100 Hz (or whatever frequency the crossover is set between top & bottom) to both, bring up the gain on the mic so you see "0 VU" on the mixers output. Reverse polarity and the output should drop, in a perfect world there would be no output, usually about 15 dB drop is the maximum you will see. Adjust delay on the top cabinet for the least output, then put the polarity back to normal. Also realize that around 9ms is a 360 degree phase shift at 100 Hz, same as reversing polarity- close to the horn path length. The cabinets could be "in phase" with no delay, or around 8 ms, and then again with double that amount, tops lagging by one wavelength.
That said, depending on the top cabinet output phase at the crossover point (bass reflex is also known as "phase inversion"), I can't tell you which polarity will be "normal".
With a program like REW, you can see the phase curves and then align them, but an RTA (or dB meter, what a mic into the board is emulating) is phase blind.
Art
I use the RTA420 for my knockabout test mic.
Microphones
Note that it is pin 3 hot, while the convention is normally pin 2 hot, so it inverts polarity...
The used one I purchased is within a few dB of the B&K 4004 (which probably are well over $1000 with the 130volt power supply) mics I use when more precision is desired.
Attachments
http://www.amazon.com/BEHRINGER-MEA...=1438373394&sr=8-1&keywords=behringer+rta+mic
I think I read a comparison somewhere and this guy seemed to do incredibly well. I just cannot remember the specifics to know if it would apply to the application I am looking for now. Have you any experience with this model?
I think I read a comparison somewhere and this guy seemed to do incredibly well. I just cannot remember the specifics to know if it would apply to the application I am looking for now. Have you any experience with this model?
Hmm... I think a 180 degree phase shift is equivalent to a change in polarity. 360 degrees brings you right back around to where you started
.On the topic of measurement mics, anybody have experience with the minidsp UMIK?
UMIK-1 | miniDSP
I like the idea that it's just USB so I could eliminate the mixer board I use as a preamp with the mic I have from my driverack. Not that I'm really in the market for a new mic but I'm curious.
UMIK-1 | miniDSP
I like the idea that it's just USB so I could eliminate the mixer board I use as a preamp with the mic I have from my driverack. Not that I'm really in the market for a new mic but I'm curious.
Zettairyouiki, did you ever find more info on this? I checked it out after you posted and was waiting for a response myself. It seems the rta420, ecm8000, minidsp, a Dayton that escapes me are all similar rebrands. I found an interesting note from one place stating the ecm8000 has become so inconsistent it isn't worth them making a cal file anymore. However they were still making it for the similar other brands. The minidsp really presents an awesome lil package but are there times when having an xlr connection is required?
XLR connectors are far more robust than RCA.
XLR connectors are used for balanced line operation, +(pin 2) -(pin 3) surrounded by a shield (pin 1). Low impedance twisted pair balanced lines can be run hundreds (even thousands) of feet with noise immunity. DSP using XLRs generally can drive multiple amp sides with no problem.
RCA connectors are usually a higher impedance and 30 feet or so is about the limit of cabling before high frequency loss and noise problems. The higher impedance and generally lower drive level may not drive less sensitive (or multiple) amplifiers.
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