Film-Tech Forum ARCHIVE: DTS Sub Level Adjustment

This is topic DTS Sub Level Adjustment in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jeremy Weigel (Member # 4208) on 05-16-2007, 07:20 PM:

Is there not seperate gain controls for analogue and digital sub levels as with Dolby or the DFP-3000?

Posted by Monte L Fullmer (Member # 2797) on 05-16-2007, 07:26 PM:

Depends on which player/processor you have..6 and 6D's the panel over the 4 LED display has trimpots for outputs, the 6AD is setup in the programming.

Posted by Jeremy Weigel (Member # 4208) on 05-16-2007, 08:05 PM:

Oops. 6AD. It has the trim pots on the D744 board and there is also a level adjustment screen on the audio set up menu. The setup instructions say to use the D744 controls for setting all levels throughout with internal pink noise, but these control both analog and digital sub levels as do the level adjustments on the audio set up menu. Basically I'm not getting the 10db in-band gain for digital, but when I adjust the trimpot on the D744 it also increases the analogue level which then way too much gain. What am I missing?

Posted by Monte L Fullmer (Member # 2797) on 05-16-2007, 08:40 PM:

Basically with any "A" chain adjustments: you do optical first then digital comes behind it.

Optical SPL's are 85dB for left, center, right, - 82dB for surrounds, and 91dB for Subbass.

Get you a RatShack SPL meter for less than 40 bucks, set the weight to "C" and to slow response. Stand in the back 3d of the house and a bit to either side to do these readings with pink noise loop running in the projector..(if you already have all of these items, then please disregard above comment..)

Posted by Darryl Spicer (Member # 711) on 05-16-2007, 08:54 PM:

Set the analog sub to 80db if you want the digital to be 90db on the DTS.

Posted by Gordon McLeod (Member # 33) on 05-16-2007, 09:15 PM:

Monte said "Get you a RatShack SPL meter for less than 40 bucks, set the weight to "C" and to slow response. Stand in the back 3d of the house and a bit to either side to do these readings with pink noise loop running in the projector..(if you already have all of these items, then please disregard above comment..) "
2 things are incorrect
1 A sub cannot be set with a SPL meter it requires a RTA
2 Pink noise loops are not recorded at the 50% reference level except on the older USL film

Posted by Monte L Fullmer (Member # 2797) on 05-16-2007, 10:19 PM:

thx Gord on the corrections. - Monte

Posted by Jeremy Weigel (Member # 4208) on 05-17-2007, 12:39 AM:

Darryl, so are you saying that the DTS automatically "boosts" the sub level rather than setting it manually as with a CP65/DA20 combo or the SDDS sub gain on the DFP-3000?

Monte/Gordon, I'm using a Goldline DSP-30 RTA with an USL multiplexer.

Posted by Steve Guttag (Member # 268) on 05-17-2007, 03:30 AM:

Since the digital subwoofer level is exactly 10dB above analog, some systems just add 10dB of boost, period. A notable prociessor that does this is Panastereo's CSP1200 and I guess the DTS6AD. Personally, I like the separate trims.

Posted by Darryl Spicer (Member # 711) on 05-17-2007, 10:13 AM:

Yes, if your processor does not have separate trims for the analog and digital subs it will boost the signal by 10db on the digital. The XD-10 has it's own digital adjustment for subs if the processor does not have separate adjustments.

Posted by Jeremy Weigel (Member # 4208) on 05-17-2007, 02:23 PM:

Ah OK. I just wanted to make sure that I wasn't over looking something in the DTS setup guide. In fact, they don't even go into setting up the sub other than setting the SPL on the D744 board to 85db in section 5.3 .

Posted by Tristan Lane (Member # 1169) on 05-17-2007, 02:49 PM:

Make sure to check the menu option for the 10db offset on the 6AD. The offset can be enabled or disabled via the menu.

Posted by Jeremy Weigel (Member # 4208) on 05-17-2007, 04:59 PM:

Called and spoke with DTS tech support. The manual I received with the unit and the one in the manuals section is out of date. They added parametric EQ'ing to the firmware.

Posted by Cameron Glendinning (Member # 3516) on 05-17-2007, 10:19 PM:

One interesting point. There seems to be no standardised approach for sound mixers re addition of sub bass. Some seem to be adding it both to the combined stage channels and the LFE, not either or!!!!! Producing some very inconsistant results between movies.