Calibrated- vol. at “0” channel levels are all set at (-) “negative “ #s is that OK? (1 Viewer)

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Roger Dressler
Dolby Laboratories

My Yamaha internal test tone REF Calibration Mark is nearly identical to my ...

1) Video Essentials* @ 75 dB

2) AVIA @ 85 dB

3) Sound&Vision HT Tune-up @ 85 dB

4) Dolby Labs Explore Our World DVD @ 75 dB

5) Delos DVD Spectacular* DD-5.1 tones @ 75 dB
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*Dolby Labs Consultant Roger Dressler (also HTF member) named is in the Credits.

Phil

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The AV Receiver's internal test tones are -30dBFS tones, so if you're going to use that, the correct SPL = 75 dB.

Phil:

That is supposed to be the case. But with my 3803, with the Master Volume set to 00 and all speaker levels adjusted for 75 dB all around, when I pop in the Avia disc, the tones are only 5 dB louder (i.e., 80 dB).

If the Denon test tones really were -30, then the Avia disc would have provided an 85 dB reading at the same exact settings.

That means one of two scenarios are correct:

1) The Denon test tones are "correct" at 30 dB below Reference Level and the Avia test tones are "incorrect" and only 25 dB below Reference Level.

Or

2) The Denon test tones are "incorrect" at 25 dB below Reference Level and the Avia test tones are "correct" at 20 dB below Reference Level.

FWIW, I tend to side with Scenario #2 since Avia specializes in HT calibration and it's playing through the DVD player.

Kevin:

Just to be sure you understand - you can use the Avia tones at any volume to balance all the speakers. But the combination of individual speaker settings (which I prefer at 0 or less) and Master Volume setting which gives you 85 dB on the meter will be true Reference Level on playback.

If you elect to keep your individual speaker settings at 0 or less, it is likely you will not hit 85 dB with Avia unless you crank Master Volume up to around +5 (or so).

Also, Reference Level is simply a benchmark by which we can all compare playback volumes. Depending on the DVD, I'm at anywhere from 5-15 dB below Reference Level for comfortable (and safe) HT playback.

Regards,

Ed

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... I'm at anywhere from 5-15 dB below Reference Level for comfortable (and safe) HT playback.

Like you Edward, my usual once or twice a month Friday NITE DVD w/family and friends HT SPL Level = -10 dB below REF Level**. Loud enough to move the floor, couch, air, wall, pant legs when the DVD sub-sonic LFE calls for it and still audible enough to hear the dialog tracks during the quieter / whispering moments of the DVD movie!!

**I only know that I'm @ -10 dB below REF Level because I know where my REFERENCE Calibration Mark is.

Phil

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A comment was made to keep levels at 0 and below. Is that more a preference or benefit? All I know is that after calibrating at 00 / 85 db my ears were starting to ring. Should I go back and raise the volume to bring the channels below 0?

Good question, and it brings up a very valid point..

If you calibrate to 0 on your volume knob at a reference of 85 dB, thats all well and good, but in most domestic environments, LISTENING at that level is way too loud.

And I am not sure I grasp the importance of keeping your channel level trims at 0 or below. I should think that any level between the min and max should be fine. Its all a function of the sensitivity of your amp, the level of your preamp outputs, the sensitivity of your speakers, the length of cable, etc. etc..

In my rig, I typically have them set between 0 and +3, depending on the channel. And the sub level will depend on the level of your sub amp, I do have mine set for +1 at 85dB, but I don't see this as an absolute.

I forget what 85dB equates to in terms of peak levels, but I want to say calibrating for 85dB gives you 20dB or head room, which means peaks at 105 dB at peak source level.

And you think 85dB during calibration is loud?

As was previously stated, -10 to -20 on the knob is normally what most people run....-20 when my wife is in the room, -10 when I am alone

As long as your channels are equal, I think you are OK.

BGL

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I adjusted my speakers last night to 85db using the AVIA. Receiver volume was at 00 and channel levels were between 0 and +3.

Kevin:

Again, I prefer keeping the individual speaker levels at 0 or below to minimize pre-out voltage distortion, but your highest value is +3, and you should really be just fine here and I wouldn't fret over it.

You are now getting 85 dB on Avia from all speakers at the listening position with Master Volume 00. Therefore, Master Volume setting 00 IS Reference Level for your system, in your HT room.

As Phil states, the relative channel balance is far more important that the absolute SPL at which you choose to calibrate. Nonetheless, you have now accomplished two things: 1) Your channels are all balanced, and 2) your Master Volume setting of 00 represents Reference Level. I would leave everything set exactly the way it is.

As you can see, listening to Gladiator at 15 clicks under Reference Level is plenty loud, and most people find themselves at anywhere from -15 to -5 clicks under Reference Level for comfortably loud playback.

Remember, the Avia test tones are mastered at 20 dB BELOW Reference Level, so actually spinning a DVD at Reference Level (Master Volume 00 for you) would result in SPL bass peaks of 105 dB from any given surround channel and 115 dB bass peaks from the LFE channel. If your speakers are high passed and the subwoofer is handling both the low passed bass and the LFE channel, your sub could be expected to generate upwards of a 120+ dB bass peak in the event of a simultaneous bass hit in a surround channel and the LFE channel. As you can see, Reference Level is simply too damn loud for nearly all enthusiasts.

To give you an idea of what I find comfortable for DVD playback, dialogue averages in the 70-80 dB range, and bass peaks will hit 110-112 dB. I think Phil and I are very close here in our playback level preferences.

Remember, some DVDs are mastered "cool" or "hot", so your Master Volume will vary considerably to achieve these levels. For example, I can hit 112 dB bass peaks on the DTS version of The Haunting - Creaking Pipes at 13 clicks under Reference Level. I can also hit 112 dB bass peaks on Star Wars Episode I - Pod Race at 3 clicks under Reference Level. Clearly, The Haunting in DTS is mastered MUCH hotter than SW Episode I.

So caution is the order of the day when spinning supposedly bass heavy DVDs for the first time. Don't automatically assume that all DVDs are mastered at the same level - they aren't and you can wreck an expensive subwoofer by inadvertently wicking up the volume too high the first time. I always have my SPL meter on a tripod when I'm pushing a bass heavy DVD and I keep a record of the Master Volume setting which gives me 112 dB bass peaks. That way a quick check of my "Maximum Safe Master Volume DVD" spreadsheet is all I need when doing demo's, etc.

Regards,

Ed

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I always have my SPL meter on a tripod when I'm pushing a bass heavy DVD and I keep a record of the Master Volume setting which gives me 112 dB bass peaks. That way a quick check of my "Maximum Safe Master Volume DVD" spreadsheet is all I need when doing demo's, etc.

Great idea Ed! Having a spreadsheet record w/109-110 dB glorious FAST DD/DTS LFE SPL bass peaks vs. favorite blockbuster DVD's (& Demo's), ... would certainly expedite the speed in setting the DVD watching/listening volume!!!

Phil

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Forgive me as I change the topic of this thread but when I take readings from my sub the SPL meter ( Radio Shack) flies off the scale.

In my system, I too have always fought with jumpy readings of bass frequencies, requiring way too much interpolation. What I found was the test tracks make a big difference in getting good readings.

While YMMV, I have settled on the Bass Mekanik CD's (5.0 I think). It has discrete frequencies in 1/2 Hertz increments from 20 to 99 Hz.

Also, I have purchased an Infinity RABOS kit (CD and SPL Meter). While I have used the CD to take and graph my measurements, I found the combo of the RABOS meter AND the Bass Mekanik dics gave me the best, most accurate results.

I used thuis combo to EQ my sub from 80 Hz on down with a 1/6 Octave EQ (Audio Control Bijou). It produced the best bass (by best I mean smooth, low, and free of boomy-ness) that I have ever had in my room with ny gear.

BGL

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