db scale on digital volume controls

[RX-V2400]

<font color='#000000'>The digital volume scale on my RX-V2400 goes from -91db up to 0db, which is about as loud as anyone would want, and then carries on in the positive db's.

Why are digital scales marked this way? What is the significance of the numbers. I might guess that 0db is the half way point where the amp gives 50% of its power and the numbers relate to volume levels below this but my manual is silent on this scale.</font>

 

[zumbo]

<font color='#000000'>0db is half volume, but full rated power output. I agree that this is as loud as it needs to get, and if you get into the +, you get into the distortion and can damage speakers. Play it safe &amp; stay in the -. I am not sure why they do it this way, my guess is so you will know exactly where your peak volume is and where you get into the distortion level. I love this feature.</font>

 

[micb]

<font color='#000000'>A SPL meter is a device which measures sound (vibrations) and gives you a reading in decibels.

All cinema setups from cheapy HTIB's to fully fledged multimillion pound theaters should always calibrated to balence the sound for movies.



Home Theater Calibration.

Why do we calibrate our home theaters? We do this so we can get a balance between the level of speech and all the effects out of the individual speakers

AV Receivers have a DB counter.

Having a db counter on an AV receiver is for calibration and balencing to Dolby reference level, this is acheived buy using a SPL meter and special test noise/tones.

This is mainly done for balancing movie sound.

You can calibrate with a DVD such as AVIA or use the internal test noise from a AV receiver/Processor.

The test tones/noise are recorded at a lower level than full reference, the reason the tones are recorded at a lower level is so you can balance you Home theater with out going deaf in the process.

The tones/noise are recorded at -20db below reference for a AVIA DVD and -30 db below ref for internal tones from an AV Receiver.

Both DVD and internal receiver/processor test tones methods usually give the same calibration results (although not always).

The basic method is to the the Receiver/Processor set to 00 and the tone/noise is played through each channel, you then balance all speaker channels levels to 75db or 85db on the SPL meter depending on which source the tone/noise is from.

1)The point of putting the amp on 0 and calibrating is then you can play movies at -10 and be 10 below dolby reference level or play at -40 and be 40 below dolby reference.

2)Full dolby reference is usualy peaks of 105db per channel and 115db for LFE (bass).

IF you use bass management and run speakers set to small then the LFE and sound below 80hz is passed to the subwoofer and the peak bass level is bumped up from 115 to 121 db.

This shows most subwoofers are not up to full dolby reference level.

Full dolby refenence is very loud and can be damaging to you AV kit.

Once calibrated there is no real correct volume level you should listen to, just enjoy the movie at your confortable level.

Movies do seem to be recorded at different volumes so you may have to turn up some moves more than others.

Personally I watch most movies between -25db below reference at night time and -15/20db below reference in the day, full reference is way too loud for me, I want to keep some hearing for the next 50 years.</font>