volume level question

[ryanshaw3ball]

i have a pioneer vsx-919ahk receiver and like most receivers it read out volumer starting at -70db and goes up to + 10 or 12 db. i was just wondering what exactly those numbers mean or correspond to and whats usually a safe level to operate it at?

 

[tcarcio]

Yahoo had a good answer from Paul...........

db is decibels, and it's a standard unit of measure for electronic signals or sound pressure level.

For sound pressure level, db is an absolute unit of measurement. That is, if you have a certain amount of deciblels of sound pressure level, it's a certain volume (0 db is the threshold of hearing for a healthy youth, 60 db is an average conversation 1 foot away, 125 db is a jackhammer,etc. - see the following link: http://www.coolmath.com/decibels1.htm).

For electronic signals and for differences in db of sound pressure level, db is a relative unit. Since it's based on a logarithmic scale, it works out that an increase in sound pressure level of 3 db equals a doubling of the sound pressure level, while an increase of 10 db results in 10 times the sound pressure level, and +20 db results in 100 times the sound pressure level.

For electronic signals that are based on a db scale (dbmW - decibels related to one milliwatt, or dbmV - decibels related to one millivolt, for example), the same relationship in signal increase versus db increase applies. 0 dbmV is 1 millivolt, +3 dbmV is 2 millivolts, +10 dbmV is 10 millivolts, etc.

Basically, what that control is telling you is that you can increase or decrease the signal going to the selected speaker by plus or minus 12 db, as necessary to balance out your speaker outputs (depending on where the speakers are placed, if you have more or less efficient surround speakers, or where you are sitting in the room when listening to the system).

 

[Josuah]

It's possible -0dB means there is zero voltage attenuation going on, but there's no guarantee that is true for your specific model.

Figuring out a safe level depends on what your maximum input voltage is (usually described as sensitivity) on your amp, although you probably don't have an external amp. In which case a safe level corresponds to:

Figuring out the maximum sustained power handling of your speakers. If you overdrive your speakers, you can damage them. I'm not referring to clipping, which is when you overdrive your amplifier, but just to pushing too much power through the speaker electronics.

Then of course there's what's safe for you to listen to. Extended periods of high volume sound will cause permanent hearing damage. For a few hours of music listening, I'd recommend about 75dB average at your ears. But you can find lots of places online that document dB levels, duration, and likelihood of hearing damage.

 

[edmcanuck]

You use the speaker-levelling of your receiver so that at a volume reading of 0dB, a full-scale pink noise signal produces 85dB in your room. Your receiver is then set up to produce "reference" levels according to the Dolby mixing / THX rules. On a Dolby reference/THX-mixed disc, you will then hear in your living room exactly what the engineer intended. Of course, extremely few discs follow these volume rules so it's utterly useless to set your receiver up this way. For further reading, check here.

 

[highfigh]

Volume controls act by atttenuating the signal but if they called it that, nobody would understand what they mean. 0dB is their reference output level and any -xxdB is that many decibels below the reference level. They have +dB range because some sources don't have the same output level as others. Think of the 0dB point as the red line on a tachometer- you can exceed it but it may not be pretty.

 

[Jack Hammer]

Highfigh pretty well summed it up, it is the manufacturers reference point. What that point (0db) means, in terms of how loud it is, also varies from manufacturer to manufacturer and even among the different models. In other words, -10 on a Denon 3808 is not necessarily the same loudness as -10 on a Denon 2808. It's 10db below the rated max output of that unit.

I think the tachometer comparison is probably the best description I've ever heard of what the numbers mean. 0db is just hitting redline, +10db is over revving.

 

[MidnightSensi]

Where it is safe to set your receiver greatly depends on how far away you are from your speakers, how powerful your receiver is, how sensitive your speakers are and how loud the source is recorded.

You can look at OSHA guidelines for what is safe, and then use an SPL for some tests to get an idea what a safe level is and for how long. However, I'd say you can use your head and stay pretty close.

A good tip is finding ways to lower the noise floor in your room. Things like A/C units, noisy vents, refrigerators, fountains outside, pool pumps, street noise and so forth all cause you to turn up the volume more to compensate. A quieter room allows you to run your system at a lower level while still feeling the dynamics of the track. This is especially important with dialog, because of the wide swings in the dynamics of tracks in modern movies, the voices may be pretty soft compared to the action. To understand the dialog, you turn up your system, and then when action comes it is too loud. Room decay time also influences speech intelligibility a lot.

Just some thoughts.

it works out that an increase in sound pressure level of 3 db equals a doubling of the sound pressure level, while an increase of 10 db results in 10 times the sound pressure level

It's actually 6dB is double the perceived loudness, depending on the study (I've heard 10dB places also).

 

[mtrycrafts]

...
It's actually 6dB is double the perceived loudness, depending on the study (I've heard 10dB places also).

Yes, but that is not what he was saying
Pressures double not the perceived sound level.

 

[3db]

Yes, but that is not what he was saying
Pressures double not the perceived sound level.

What?? I can't hear what your saying!! Somebody, turn it down.