Mp3 dB volume question

2007-03-21 02:41:52

What does the decibel volume related to mp3's mean? I normalized mp3's with Mp3gain and noticed this. I know the volume is SPL for something, but what? A maximum volume that they can be played at?

Thanks.

Mp3 dB volume question

Reply #1 – 2007-03-21 05:04:22

As you have your own volume control and play the music as loud as you want, it's a bit arbitrary. SPL is Sound Pressure Level and 0dB is very roughly the threshold of hearing. A typical chainsaw or pneumatic drill operator without ear defender receives around 110-113 dBa, for comparison.

89 dB is actually pretty loud so you'd tend to play back quieter than this most of the time. The original Replaygain proposal (see www.replaygain.org) refers to pink noise used to calibrate Movie Theatres for Dolby, which was designed to average 83 dB SPL on a particular kind of sound meter when properly calibrated.

Play back at any volume you're comfortable with. No maximum or minimum. 89 dB SPL was chosen as a target simply to be fairly similar to other computer sounds that you may not have adjusted using ReplayGain (such as system bleeps and clicks and non-adjusted music files, internet broadcasts or video clip soundtracks)

Mp3 dB volume question

Reply #2 – 2007-03-21 23:34:03

Yes, but isn't there any simple definition for dB level related to every mp3? In which Mp3gain program has nothing to do with (unless the dB level is some own calculation of Mp3gain).

Thanks.

Mp3 dB volume question

Reply #3 – 2007-03-22 01:32:03

89 dB is considered a "correct" amount of loudness for a wav 
Going below from it isn't a trouble, the problem is above.  You can read more information in the search of forum and more specifically in this page:
http://www.digido.com/modules.php?name=New...ticle&sid=9
An example of excessive "amount of loudness" in a wav, just downlad and listen this sample, sounds terrible:
http://rapidshare.com/files/22172870/Hellraiser.flac

Mp3 dB volume question

Reply #4 – 2007-03-22 19:15:40

I think what the Original Poster is trying to convey is this:

dB (decibel) is a relative logarithmic measurement.

For instance, dBW is the relative logarithmic of measured instantaneous power against 1 W, i.e. [dBW] = 10 x log ( P / 1 W ). dBm is relative to 1 mW.

In the case of audio... relative to what? And what actually is being measured?

Mp3 dB volume question

Reply #5 – 2007-03-22 21:29:19

dbSPL measures relative to the 20 µPa reference - the minimun level of human audability.

Mp3 dB volume question

Reply #6 – 2007-03-23 09:34:05

Ah, thanks Killes.

I always wonder about that myself