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Topic: Componet Engineering THX Clone Cards

Glenn Conatser
Film Handler

Posts: 73
From: Northern California
Registered: Aug 2001

posted 05-08-2002 10:10 PM

Hello Everyone,

Our tech is going to be installing THX clone cards in my THX 3417 booth monitors to replace some Ultra Stereo crossovers that are being used. Will these improve the sound in the houses compared to the Ultra Stereo crosovers.
These houses where built to THX spec back in 88 when the theatre was built but THX never granted certification due to some railroad tracks being near by that caused to much noise.

Thanks,
Glenn

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 05-09-2002 12:08 AM

I've never used the CE cards, but CE is the company that made the cards for that monitor, so I would assume they are virtually identical. That being assumed, the answer is YES! I personally do not like the Ultra Stereo crossover cards at all.

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Glenn Conatser
Film Handler

Posts: 73
From: Northern California
Registered: Aug 2001

posted 05-09-2002 12:42 AM

Hi Brad,

I was thinking of using these crossovers after there pulled and talking to my tech about bi amping some of my other houses. The USL crossovers being used look like they where attached to cards using screws. Can these crossovers be used with QSC1400 amp and be plugged into the back like ive seen at some other locations. Im looking at economical and effective ways to upgrade our sound systems. They tend to sound somewhat harsh and compressed.
Granted they probably havent been EQ'd in ages and that would help a good bit . But im looking to get that big open sound with alot of punch that you get with bi amping.

Glenn

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 05-09-2002 01:43 AM

I really wouldn't know, as I've never even considered it. I'm sure someone else will chime in here soon with a definitive answer.

You wouldn't be running your films in analog with only Dolby A noise reduction, would you?

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Ken Layton
Phenomenal Film Handler

Posts: 1452
From: Olympia, Wash. USA
Registered: Sep 1999

posted 05-09-2002 09:25 AM

The CE THX clone cards for the monitor are excellent and worth the money. There were some hum problems on the early cards, but CE took care of it pronto (all it needed was to remove one part and add a jumper wire). When installing the new cards, you will have to reset the SPL levels in the auditorium.

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Glenn Conatser
Film Handler

Posts: 73
From: Northern California
Registered: Aug 2001

posted 05-09-2002 10:02 AM

Brad,
Dolby A is our back up format on these houses being that CP55's our the processor in use along with the digital unit.

Glenn

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Bill Purdy
Expert Film Handler

Posts: 139
From: Seattle, WA
Registered: Oct 1999

posted 05-09-2002 11:12 AM

Just a quick correction, we never made the original cross-over cards. These were made by THX themselves to the original Tom Holman design. Our replacement version has been made to emulate as closely as possible the original so that installation is quick and easy. As the replacement cards were designed nearly twenty years later than the originals we had the advantage of better parts and therefore the new cards might even be better than the old ones. (A quick anecdote; Tom Holman recently told me that we could have copied his circuit as it was never part of the THX patent.)

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Bill Purdy
Component Engineering

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 05-09-2002 04:26 PM

Hmmm, what am I confusing here Bill? Did you make the chassis and THX put the cards in it?

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 05-09-2002 09:30 PM

FWIW,

The Ultra Stereo XTA-1 and XTA-2 crossover modules (not aware of the "cards") are fine. They clearly were based on using JBL speakers (4675 or 4670, respectively)....if you use those, they practically need no eq. The XTA-300 system is actually quite nice for what it is. The passive bypass the XTA-300 uses should be studied by anyone designing cinema crossovers. The passive bypass has a rather good response that most active crossovers wish they had!

That being said, I have no experience with the CE crossovers.

Steve

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"Old projectionists never die, they just changeover!"

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Bill Purdy
Expert Film Handler

Posts: 139
From: Seattle, WA
Registered: Oct 1999

posted 05-10-2002 10:25 AM

Brad, you are now correct. As the cards have always been leased it has been necessary for THX to maintain that part of the deal. We built the box for the primary purpose of powering the cross-over cards, but adding the monitoring function made it better and something to carry the THX logo. If your experience goes back to the beginning of THX you will remember that the first ones used a sort of generic card frame already being made by "dbx". "dbx" however, wouldn't get the necessary electrical approvals nor modify their box to better suit THX's needs and so the whole 3417 project began.

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Bill Purdy
Component Engineering

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