Why would the booth monitor contain crossovers?

Aren't they usually in the processor or the loudspeakers? I've also seen them as add-ons for the amps.

But...in the monitor? What gives?
 

Could you please post some recommendations for rack-mounted crossover networks?

I am using JBL 4675-8LF speakers and QSC 1400 amplifiers.

I do not like the little boxes that plug into the back of the amps. They are ugly and they can be bumped out by accident.

~Manny.
 

Ultra Stereo's XTA-300s are VERY tough to beat in terms of matching to a JBL 4675C or equivalent...their passive bypass mode is better than most people regular crossovers.
http://www.uslinc.com/products/xta.htm

I also use RANE crossovers (2-way and 3-way)
http://www.rane.com/

Below is the rear view of a pair of RANE 3-way (AC23B) crossovers wired into a rack we recently assembled

Next is the front of the rack (with a Dolby CP-650 w/EX)...the AC-23 does has it's share of knobs! Continiously adjustable delay on any two of the three sections is a tough one to beat for fast accurate alignment.

Lastly, is a picture of the rear of the rack...at the bottom is a QSC SF-3 (sub filter) that is similar to their rear mounted crossovers (the XC-3) which are also quite good.

Personally, I don't like having the crossover in the processor...it makes the wiring of the monitor unecessarily cumbersome. Furthermore, not all crossovers are made equal. Just because you like a processor doesn't mean they make a good crossover.

I like crossovers on the amplifier or in the monitor...no extra work is involved. If I were you, I'd problably just get the USL XTA-1s and be done with it...never had one fall out and who is looking the back of your racks to judge prettiness?

And since DIGITAL is in...there are DSP solutions available too. Items like QSC's DSP-3 and DSP-4 which will also go on the back of the DCA amplifiers. (though they can work standalone). DSPs clearly offer the most flexibility in terms of features and customizing the crossover (and other functions).

Check out the DSP-4 at
http://216.149.53.76/products/amps/dsp/dsp4.htm

Or the less expensive (though a bit noisier but has phoenix connectors) DSP-3.
http://www.qscaudio.com/products/amps/dsp/dsp.htm

Steve

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"Old projectionists never die, they just changeover!"

The only need for a booth monitor is to monitor....nothing more other than it can be a good troubleshooting device to check for audio distortion, and to see if you have a clean signal coming out of the processor and/or power amps.

Hey, Steve....did you wire those racks? A real beautiful top-notched job! Wow! I am very impressed by the quality of wiring and workmanship in those pictures!

As to the booth monitor, I agree as to it's funcion. However, you are already running a set of low-level lines to it for minitoring anyway...as such it is an acceptable area to have the crossover. (likewise on the amplifier).

I tend to not like combining components since a good monitor maker may not be a good crossover maker and if a single piece dies, it shouldn't take down the system. Then again, I'm normally wiring racks in bulk so saving time is also a concern.

Steve

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"Old projectionists never die, they just changeover!"

Thanks for those GORGEOUS photos. I'm fastidious about wiring but that is an awesome example of what to shoot for in terms of tidiness.

Thanks also to you and Richard for the info and the links.

~Manny.

"Who would have thought that when it came time to cash in your chips, this old "diseased maniac" would be your banker?" -- Lex Luthor in Superman: The Movie.
 

These racks use my favorite crossover the Component Engineering and the the processor in one is a CP65 the other is a Mod6 and the crossovers are Smart

This is during construction of the Fairview Complex in toronto and both these booths are 70mm equiped

P.S. Hey Gordon, Didn't mean to leave you out man. Your systems looks great as well!

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Samuel Hunter Sr.

Death to DLP (Video)

I have found that hums and noises are funciton of what you use and how you install them.

Steve

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"Old projectionists never die, they just changeover!"
 

Steve,

Your racks look great! What kind of wire are you using, especially the different colors of wire?

Also, how are you labeling the wires? Are you using a label under transluscent heat shrink in various colors? Are these computer generated labels, p-touch labels or what. I have been trying to find a cheap, very easy, and flexible labeling system. Anyone got any favorite labeling methods?

Gordon,

Your racks look great, too! I really like the open frame racks, although that is not what we offer here at SMART. If I were doing racks for my own use, I would use the open frame variety.

Sam said, "Its refreshing to see quality work like this. Believe me I have seen many a rats nest as I'm sure all you guys have."

Yeah, Sam, I agree.

I would like to see a topic with pictures like this to show how it SHOULD be done. If anyone has a picture of their favorite rack wiring job, please post it, or maybe better, just provide a link to it so we don't clog up too much of Brad's bandwidth.

I am sure "normal" people would think I am crazy, but to me this kind of job quality is like a work of art, and is something I enjoy seeing in a way similar to my enjoyment of a nice painting or sculpture.
 

Also, how are you labeling the wires? Are you using a label under transluscent heat shrink in various
colors? Are these computer generated labels, p-touch labels or what. I have been trying to find a
cheap, very easy, and flexible labeling system. Anyone got any favorite labeling methods?"<<

Once again thanks...

The different color wire is a mixture of Belden and West Penn wire. I use "snake" cable to come out of Dsubs (6-jacketed, shielded pairs). West Penn wire #291 comes in all of the colors. Belden #9451 also come in all of the colors...I much prefer Belden over West Penn.

As to labling...I am a minimalist. The colors speak for themselves...

Left = Red
Center = Blue
Right = Green
Ls = White
Rs = Yellow
S/W = Brown

I didn't invent them...Dolby has been using those colors since the CP-50 and onwards on their test points (with red and green on each and every forward scan solar cell).

The additional channels...
BSl = Violet
BSr = Orange

Left-Center = Grey
Right-Center = Black

The colors are used thoughout from cell to speaker. Makes things easy to trace.

The speaker wire gauges will determine what section of the speaker it feeds...larger going to the more LF section.

When it comes to labels...I tend to use 3-M's label tape. Also P-touch for the fronts of the equipment. Depending on the job, sometimes cables are tagged too.

I'll probably give Brady's and Panduit's label makers a bit more of a closer look.

I generally wire my racks so things are self-explanitory and adequate service loops (though I don't make them loops to avoid potential inductance) are "stashed" thoughout to allow for future changes (really helped out when "EX" happened a few years ago.

Steve

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"Old projectionists never die, they just changeover!"
 

Please use the upload feature of this forum. That is what it is there for.

My compliments too! A wonderful job!

A question: is it a three amped system? If so, are the first three amps a three channel ones? If yes, I didn't know that they exist.

Just for my curiosity, how big is the theater where you installed that rack?

Bye

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Antonio Marcheselli
Florence, Italy
 

Were you referring to my links? If so, they are all to pages, not pictures.

Antonio,

Those amps were QSC 4-channel amps. Channels 1 and 2 were bridged mono to feed the LF section. Channel 3 feeds the MF section and Channel 4 feeds the HF section. Thus you can put the power where you need it.

The theatre has a screen about 40-feet wide and the theatre is about 65 feet deep.

Steve

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"Old projectionists never die, they just changeover!"
 

Not to speak for Brad, but I think he was referring to my idea of posting pictures as links to outside servers. I was not aware until this evening about Brad wanting us to upload pictures to the film-tech site to prevent possible future broken links and for archival purposes. Now I know.
 

Steve

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"Old projectionists never die, they just changeover!"
 

As a for instance...most manuals will identify each connector and control on a unit...Rane is no exception. On the AC23 (3-way crossover) manual...when it comes to the power switch...the description is "two guesses"

The manuals are available for download from the site. There is also some very good general information contianed in their manuals and technical notes.

Rane also has the infamous PI-14 Psudoacoustic Infector...I suggest you all look it up to see this company has a sense of humor. http://www.rane.com/pdf/old/pi14dat.pdf

Steve

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"Old projectionists never die, they just changeover!"

I saw the QSC web: they are switching ones! I didn't know that there were multichannel professional amps and I can't imagine a non-switching 4 channel amplifier...

Bye
Antonio
 

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