I can go from 81dB to 84dB, but nothing in between. The other player like this one gave me a smooth increase/decrease in all levels.

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~Manny.

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Clarification: The other DTS-6 unit in this theatre is installed in a different auditorium.

Steve: I was indeed trying to check the level with an SPL meter to do a quick check of the levels. Curious as to why it doesn't work..?

I have an RTA on order, but it has not arrived from Miami yet, so I guess I'll just have to wait until then.

This player was installed about two years ago and as far as I can tell (just by asking around) they haven't used it. As it turns out, this system needs a new timecode reader. It's been turned on everyday for the past two years or so, even though wasn't being used. I guess they killed the LED?

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~Manny.

Now...where was I ?
Leonard Shelby, MEMENTO.

Did you try a dry contact cleaner on the pot? I had to clean my offset switch and now they work perfectly.

Bye
Antonio

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For SPL to have any meaning, one has to know over what range the frequency is being measured. That is why there are weightings and specified range. It works for setting the stage channels since they are wide band, we limit the SPL meter's response to the "C" weighting and we have a very uniform criteria for setting frequencies over the operating range (the ISO 2969 curve). The wild card in this is the typical inaccurate Radio Shack meter that most seem to use. The microphone in it is notoriously not flat and different readings can be had based on how it is aimed, and just which frequencies it thinks deserve emphasis.

But with a subwoofer, we have an inherently band limited frequency range. Particularly for DTS where the subwoofer rolls in at 80 Hz. With bass frequencies, you often can get resonances that can exaggerate particular frequences in a non linear fashion. So say you have a resonance situation, turning up the sub level a small amount might have a big affect on one frequency and show up on the SPL meter but it isn't representitive of the whole subwoofer spectrum.

Steve

If you are having this same problem, then it is the pot for the subwoofer adjustment. Cleaning the pot did nothing, so in our case either the pot or the entire board was bad. I didn't stick around long enough to find out.

Steve

To calibrate the DTS subwoofer, you should use the DS3 setup and set all levels for 300mV RMS using tone. Then, use the RTA to set CP EQ.

If you have only a SPL meter, use a DTS setup disc and play subwoofer pink noise. When that plays, turn off the surround amplifiers and adjust the DTS subwoofer level trimpot until you get about 88dB SPL in the audirorium (subwoofer speaker). That will get you by until you can adjust properly using tone and the RTA / CP.

I'm asking because I'm getting like 0mV using a multimeter, even though I'm hearing the tone nice and loud. Is that the wrong tool for this?

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~Manny.

I understood that Subwoofer channel is not full-range so that measuring the SW is not the same as measuring a stage channel.

But when you set the SW level with an SPL at the DTS unit the CP is already equalized and so there should be no resonances in the auditorium that can change the SPL meter's read.

I thought that since SW is limited 20-80 (or 20-150 with Dolby) and each subwoofer (despite the EQ) has a different frequency response, SPL is not so accurate.

A quasi-OT question: if I'm setting the SW channels with and SPL (instead with a RTA), DTS SW level is 91, and what about Dolby Level using CP500 built-in generator?

Karen,

88dB? Wasn't it with old setup disk? Is it not 91dB now???

Bye
Antonio

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Setting subwoofer level with an SPL meter is just plain wrong; it doesn't work! As Karen said, you can do a quicky level set to get you by but it has no real bearing in real life. If you don't have the proper tools, don't do the job.

Steve

Thanks to you all for being such a big help.

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~Manny.