IPB

Welcome Guest ( Log In | Register )

16 bit, 24 bit and Noise Floor
botface
post Feb 28 2012, 20:13
Post #1





Group: Members
Posts: 354
Joined: 14-January 08
Member No.: 50483



I'm involved in a discussion on a home recording forum. We are not discussing post processing, mixing or mastering just the simple capture of a single acoustic instrument.

I'm suggesting that with a recording environment that yields a noise floor of -60dbfs it makes no difference at whether you capture in 16 bit or 24 bit as you effectively only have 10 bits to work with and so any theoretical benefits of using 24 bit are lost

I'm getting arguments back like :
QUOTE
Specifically 24 bit capture files will still provide the widest range of dynamic and the greatest resolution for capturing anything


QUOTE
With 16 bit you have that many steps and with 24 you have that many more ... which means the more bits you have, the less grainy your resolution is


QUOTE
To give an example: You have a scale of 0 to 100. If you print it on a 10cm piece of metall you barely have enough place to distinguish 1mm distances. If you print it onto a 1m bar, you can have plenty more subdivisions. Of course 100 is still 100 and zero is still zero, but you have many more subdivisions. Same with digital signal. Say you would use a 2 db resolution: then you would have just four different levels to represent the different signal levels which would have to be somehow digitalized onto these four steps.
With 16 bit you have 2^16 possible steps (65536) and with 24 bits 2^24 possible steps (16777216, quite a bit more...). Whether you believe them to be more useful to represent an audio signal I leave to your own ears.I'm not claming that the perceived distance between noise level and maximum level is bigger with 24 bits than with 16 bits. It's just that you have many more subdivisions in between, and that is audible.


QUOTE
If the full theoretically possible dynamical span gets more quantizing levels per dB so must also the same dynamical span of let's say 60dB gain above recorded noise floor. I' can't see where this argument is wrong ... Maybe we're talking about different things?


QUOTE
16 bit recordings have a theoretical dynamic span of 96dB; 24 bit recordings one of 144 dB. If I take the number of possible representations of level with 16 bit, then I have 2^16/96 = 682,7 (rounded) steps per 1dB. WIth a 24 bit recording I have 2^24/144 = 116508,4 (again rounded) steps per 1 dB. So it seems that the dynamical resolution is much finer with 24 bit.


QUOTE
The scale is the same, but with 24 bits we get bigger number of smaller steps than with 16 bit at any part of the scale which allows for better resolution.
You can want to increase the dynamic range by cutting off the noise, and stretching what is left down to the negative infinity level to fill the whole range, and higher resolution of 24 bit will become very handy compared to 16 bit.


I've given examples, I've worked through the arithmetic, I've provided analogies but nobody seems to think the noise floor of the recording environment has any impact on the ability of 24 bit to capture more detail. Can any of you provide any examples or analogies that you've found to work in the past.
Go to the top of the page
+Quote Post
 
Start new topic
Replies
Wombat
post Mar 5 2012, 21:15
Post #2





Group: Members
Posts: 950
Joined: 7-October 01
Member No.: 235



What about a simple experiment? Create a silent 16bit file and turn up the volume of your system until you can barely hear the noisefloor. Now press play with an average loud song.
Go to the top of the page
+Quote Post

Posts in this topic
- botface   16 bit, 24 bit and Noise Floor   Feb 28 2012, 20:13
- - saratoga   You are correct and those people you quoted do not...   Feb 28 2012, 20:17
- - greynol   As a simple experiment, you can create a pure tone...   Feb 28 2012, 20:18
|- - Ethan Winer   QUOTE (greynol @ Feb 28 2012, 14:18) As a...   Mar 1 2012, 19:59
|- - Glenn Gundlach   QUOTE (greynol @ Feb 28 2012, 11:18) As a...   Mar 2 2012, 07:36
|- - Garf   QUOTE (Glenn Gundlach @ Mar 2 2012, 07:36...   Mar 2 2012, 12:07
|- - Arnold B. Krueger   This is another one of those situations where your...   Mar 2 2012, 14:02
|- - 2Bdecided   QUOTE (Arnold B. Krueger @ Mar 2 2012, 13...   Mar 3 2012, 19:56
- - hlloyge   Oh, just work in 24 bits so you can have more prec...   Feb 28 2012, 20:21
- - DVDdoug   Let's look at the "ruler" example - ...   Feb 28 2012, 20:26
- - greynol   Please, before submitting any more abject analogie...   Feb 28 2012, 20:43
|- - saratoga   QUOTE (greynol @ Feb 28 2012, 14:43) Plea...   Feb 28 2012, 20:51
|- - Garf   QUOTE (greynol @ Feb 28 2012, 20:43) Plea...   Feb 29 2012, 15:48
- - KMD   greynol is right, sounds below the noise floor are...   Feb 28 2012, 20:46
- - greynol   You're right. Case in point: create a 1k tone...   Feb 28 2012, 21:22
|- - saratoga   QUOTE (greynol @ Feb 28 2012, 15:22) You...   Feb 28 2012, 21:30
- - mjb2006   Most explanations—even those for technical audienc...   Feb 28 2012, 21:22
|- - spindle   QUOTE (mjb2006 @ Feb 28 2012, 20:22) Most...   Mar 4 2012, 12:12
|- - saratoga   QUOTE (spindle @ Mar 4 2012, 06:12) Forgi...   Mar 5 2012, 07:53
|- - Arnold B. Krueger   QUOTE (spindle @ Mar 4 2012, 06:12) Forgi...   Mar 5 2012, 13:27
||- - spindle   QUOTE (Arnold B. Krueger @ Mar 5 2012, 12...   Mar 6 2012, 13:36
|- - 2Bdecided   QUOTE (spindle @ Mar 4 2012, 11:12) Forgi...   Mar 7 2012, 11:41
- - greynol   I should have led with my second example.   Feb 28 2012, 21:39
- - WernerO   QUOTE (botface @ Feb 28 2012, 20:13) I...   Feb 29 2012, 08:36
|- - knutinh   QUOTE (WernerO @ Feb 29 2012, 09:36) That...   Feb 29 2012, 11:00
|- - Arnold B. Krueger   QUOTE (knutinh @ Feb 29 2012, 05:00) QUOT...   Mar 2 2012, 01:24
- - icstm   your point about single tones vs white noise is al...   Feb 29 2012, 18:56
|- - Garf   QUOTE (icstm @ Feb 29 2012, 18:56) your p...   Mar 1 2012, 08:40
|- - botface   QUOTE (Garf @ Mar 1 2012, 07:40) The orig...   Mar 1 2012, 10:13
- - 2Bdecided   Try lossyWAV with --bitdist to see how many bits i...   Mar 1 2012, 10:51
|- - Garf   QUOTE (2Bdecided @ Mar 1 2012, 10:51) Try...   Mar 1 2012, 11:19
- - googlebot   A noise floor can be considered part of the signal...   Mar 2 2012, 20:59
|- - knutinh   QUOTE (googlebot @ Mar 2 2012, 21:59) A n...   Mar 2 2012, 21:09
|- - googlebot   As discussed earlier in the thread it is not trivi...   Mar 2 2012, 21:18
|- - Garf   QUOTE (knutinh @ Mar 2 2012, 21:09) QUOTE...   Mar 4 2012, 10:12
- - Notat   I wish I knew of such a reference. I'll take a...   Mar 5 2012, 05:45
- - bandpass   Here's a wood-working analogy Suppose that y...   Mar 5 2012, 15:16
|- - icstm   QUOTE (bandpass @ Mar 5 2012, 14:16) Here...   Mar 6 2012, 11:05
- - icstm   QUOTE (Garf @ Mar 2 2012, 11:07) As far a...   Mar 5 2012, 16:51
|- - Arnold B. Krueger   QUOTE (icstm @ Mar 5 2012, 10:51) QUOTE (...   Mar 5 2012, 17:34
|- - Arnold B. Krueger   QUOTE (icstm @ Mar 5 2012, 10:51) QUOTE (...   Mar 5 2012, 17:45
|- - googlebot   QUOTE (Arnold B. Krueger @ Mar 5 2012, 17...   Mar 5 2012, 20:52
|- - icstm   QUOTE (Arnold B. Krueger @ Mar 5 2012, 16...   Mar 6 2012, 10:53
|- - Arnold B. Krueger   QUOTE (icstm @ Mar 6 2012, 04:53) QUOTE (...   Mar 6 2012, 14:12
|- - 2Bdecided   QUOTE (icstm @ Mar 6 2012, 09:53) OK, but...   Mar 7 2012, 11:55
- - Wombat   What about a simple experiment? Create a silent 16...   Mar 5 2012, 21:15
|- - googlebot   QUOTE (Wombat @ Mar 5 2012, 21:15) What a...   Mar 5 2012, 21:18
- - Wombat   QUOTE (googlebot @ Mar 5 2012, 21:18) Tha...   Mar 5 2012, 21:22
- - icstm   I understand that. So I guess the problem is with ...   Mar 7 2012, 13:46
- - KMD   Noise "floor" is an bad phrase as signal...   Mar 7 2012, 13:53


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 19th April 2014 - 05:30