I've just read the CP500 installation manual. Very interesting!
I've read that there is the possibility to cut off from surround channels frequencies under 50 or 100 Hz just changing an header.
My question is: what happened to the discarted sound? Dolby manual talk about a "separate bass frequencies unit" (subwoofer??). But where this bass unit can take the discarted frequencies? Is there on the CP500 a plug for this cut frequencies?
I also understand that on Dolby Cp500 is impossible to set "No-Cut" for surround, the minumal cut is 50, isnt' it? So I suppose that for my JBL 8340 the correct setting is "50Hz", right?

Second question: is it possible to set a Cp500 to cut off from LCR channels bass frequencies under, for example, 100Hz and send them to subwoofer?
I know that this is possible on a CP50. What about CP500 (without creating a custom format)?

Thanks to everyone and sorry foe eventual syntax errors!

If you have the Cat. 683 crossover card, you can augment your surrounds with bass speakers or equivalent for deeper bass. Their outputs show up on the bottom right connector (as facing the unit from the rear).

This leads to your second question of high-passing the stage channels at say 100Hz and feeding the rest to the subwoofer(s). You can do that, sort of, again using the Cat. 683 you set the the crossover to 100Hz for the stage channels. The signal below 100Hz will be present on the normal output connector. You will then need a summing amplifier to mix the stage channels in with the subwoofer (or I suppose an "on-the-cheap" way would be to just use resistors on the LF outputs and the S/W output, since you will have separate Hf and Lf trims on the CP-500).

It may be possible to remove the high-pass filter. Hopefully Ken is lurking out there. My guess is that if you remove the header you might get most of the bass. Since the header, no doubt, is switching resistor values to create the different frequencies, there are bound to be capacitors near by to complete filter. Since they didn't use a simple link, I'll wager it is at least a two-pole filter.

Steve

However I understand that it is not a "common" operation, there isn't just to change a "jumper" for obtaining that result.

I know a thetare that have an old CP50 with all three front speaker cut at 100Hz to subwoofer. Once, their subwoofer gone and I realize that all bass and midlle-bass frequencies were made by subwoofer. But middle-bass frequencies made by subwoofer sounds different than the same frequencies made by a front speaker. The result was that "enemy of the state" sound very very different than another theater with middle-bass frequencies made by speakers.

Yes the "stage channels" are Left Center and Right. To set those frequencies, you MUST have the Cat. 683 crossover card installed. There are several pre-made crossovers that come with the card and instructions on how to make your own with the desired frequency.

As to the CP-50 being able to handle "bass-management" as it is sometimes termed. This is NOT a standard function of the processor. Left/Center and Right have no crossover or bass management in their signal path. If you have a subwoofer connected to say a Cat. 160, then you can simulate what you mention to some degree. To do this, turn the bass controls down on the L, C and R Cat. 64 equalizers and use the Cat. 160 to fill-in the bass. This isn't perfect since the Cat. 160 uses a downward expander with the presumption that any "bass-extension" films would have compression on the bass so that non-Dolby (ie Mono) theatres would not see an exaggerated bass track that it would not be able to handle.

In the early 80s, often a subwoofer, if the theatre was so equipped, was turned off if the film wasn't recorded with "bass-enhancement" in mind since the bass would seem excessive and unatural.

If this is the type of bass-management you are looking for then the CP-500 can also accomodate....When tuning the CP-500 you can set the optical subwoofer to work at either 50Hz or 100Hz...Select 100Hz and as with the CP-50, turn down the Bass levels for L, C and R in the equalizing section.

Steve

The theater I'm talking about seems not to have any particular device to put stage's bass on subwoofer channels... Very strange. The tech (not my tech!) told me that Cp50 and 500 has an internal crossover to set how much frequencies from stage channels has to be delivered to subwoofer channel...

The Cat. 160 as used in the CP-50 for the subwoofer, low passes the subwoofer at 120Hz (or there abouts) and there is a suitcase link to high pass the subwoofer at either 22 or 100Hz. That is about the limit of the tuning. Obviously digital wasn't a consideration of the CP-50.

With the Cat. 560, the CP-50 can have the now standard choice of either 50Hz or 100Hz low pass filter for Optical Only!

The only way you can accomplish the "bass-management" you seem to indicate you want would be to use the optional Cat. 683 crossover card as I said if you want to do it strictly with the CP-500. Using external crossovers and such will let you do it with any processor. QSC is planning or has implimented a bass-management feature in their DCM-2 and DCM-3 monitor/crossovers with an optional card. John Gordon, who looks in here from time to time, can give you a better update.

Steve