IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
Applying Gain to 16-bit Recordings
Engelsstaub
post Jul 18 2012, 11:07
Post #1





Group: Members
Posts: 545
Joined: 16-February 10
Member No.: 78200



I have a few questions regarding some 16/44.1 recordings I have that could be a bit louder. I wanted to boost the gain to somewhere around the point where peaks will be around -1dB without clipping. (It seems that typically the peaks are around -3dB and the meat of the recording is around 6dB and often lower.)

The files will first be upsampled to 32-bit(float)/44.1 and edited in iZotope RX2 Advanced. (Editing consists of light declicking, some possible noise removal between tracks, etc. and then resampling/dithering back.) My questions are these:

1. Is there any reason why applying gain would effect the quality of the original recording in the resulting product? (Would it have just been better to get the level set closer in the first place tongue.gif ?) I know that reducing the volume is "losing bit depth," as I've read this from members in older threads while searching earlier. Is there a reduction in bit depth (or perceivable sound quality) when increasing the volume when using a quality program at the upsampled bit rate?

2. Should the gain be applied before or after the editing (or does it even matter) assuming that number one isn't a boneheaded way to approach this with respect to quality?

Basically I believe it would be ideal to make this...



...look about like this. (About 3dB louder.)



(Sorry if these questions are a bit noobish. I've been reading my ass off through the archives and still can't quite get a grasp.)


--------------------
The Loudness War is over. Now it's a hopeless occupation.
Go to the top of the page
+Quote Post
Porcus
post Jul 18 2012, 11:48
Post #2





Group: Members
Posts: 1779
Joined: 30-November 06
Member No.: 38207



Doesn't ReplayGain solve the problem?


--------------------
One day in the Year of the Fox came a time remembered well
Go to the top of the page
+Quote Post
Engelsstaub
post Jul 18 2012, 11:50
Post #3





Group: Members
Posts: 545
Joined: 16-February 10
Member No.: 78200



The target is a FLAC image that will be burned to CD-R.

It's my understanding that RG is destructive and I'm looking for a permanent solution to archive the rip and discard the original.


--------------------
The Loudness War is over. Now it's a hopeless occupation.
Go to the top of the page
+Quote Post
skamp
post Jul 18 2012, 12:16
Post #4





Group: Developer
Posts: 1343
Joined: 4-May 04
From: France
Member No.: 13875



It's rather the opposite. Permanently applying gain is "destructive", while Replaygain is not: it only applies gain during playback, on the fly, and you can change the gain value any time, losslessly.


--------------------
caudec.net
Go to the top of the page
+Quote Post
DonP
post Jul 18 2012, 12:32
Post #5





Group: Members (Donating)
Posts: 1469
Joined: 11-February 03
From: Vermont
Member No.: 4955



QUOTE (Engelsstaub @ Jul 18 2012, 06:07) *
Is there a reduction in bit depth (or perceivable sound quality) when increasing the volume when using a quality program at the upsampled bit rate?


That ship already sailed when you made the recording, That is to say anything you lost is already gone whether or not you increase the level, but 16 bits has more than enough extra range compared to the S/N ratio of vinyl that you are really ok.

Go to the top of the page
+Quote Post
Engelsstaub
post Jul 18 2012, 13:00
Post #6





Group: Members
Posts: 545
Joined: 16-February 10
Member No.: 78200



skamp: of course you're correct in the sense as you've stated it. I know it doesn't destroy the file it's applied to. -But- if I were to use RG and then finalize the recording, rather than specialized tools, it would be imprecise and perhaps destructive to peaks and such. IOW it's not a solution to my particular needs. It's rather a solution for people who want to normalize or boost the volume of music files on their DAPs and the like.

I apologize for not wording things properly.

DonP: so its fine to be imprecise with levels as long as it's not too low and obviously not so loud as to be clipped? IOW: increasing the gain, through the steps I've outlined, is not going to be perceivably destructive or detrimental to the source? (I don't understand the concept of "losing bits" as I've read it here in other threads.)


--------------------
The Loudness War is over. Now it's a hopeless occupation.
Go to the top of the page
+Quote Post
2Bdecided
post Jul 18 2012, 14:34
Post #7


ReplayGain developer


Group: Developer
Posts: 4945
Joined: 5-November 01
From: Yorkshire, UK
Member No.: 409



Your question is thoroughly discussed and answered in this thread...

http://www.hydrogenaudio.org/forums/index....showtopic=81660

The short answer is that while some people will claim it can make an audible difference (such people who claim anything makes an audible difference, but wouldn't dream of trying an ABX test to verify the claim), the change is at about -90dB FS and therefore completely inaudible in vinyl rips. (Completely inaudible in anything unless it has quiet passages where you choose to increase the volume).

Hope this helps.

David.

P.S. ReplayGain is not destructive (except WaveGain - and that's no more destructive than any other change of gain), but it's not particularly useful or relevant if your aim is to peak normalise (or -1dB FS normalise) a CD-R.
Go to the top of the page
+Quote Post
Engelsstaub
post Jul 18 2012, 14:46
Post #8





Group: Members
Posts: 545
Joined: 16-February 10
Member No.: 78200



QUOTE (2Bdecided @ Jul 18 2012, 08:34) *
Your question is thoroughly discussed and answered in this thread...


That actually does help, David. Thanks for the link. My search-skills are seemingly lacking lately laugh.gif

EDIT: I actually didn't have to get much farther than DVDdoug's initial response to find the answer I needed, but I'm going to read the rest of the thread anyway. There's plenty I could stand to learn. Thanks again.

This post has been edited by Engelsstaub: Jul 18 2012, 15:04


--------------------
The Loudness War is over. Now it's a hopeless occupation.
Go to the top of the page
+Quote Post
db1989
post Jul 18 2012, 15:30
Post #9





Group: Super Moderator
Posts: 5157
Joined: 23-June 06
Member No.: 32180



Please note that some in that thread appear to be quite confused. Examples: Right from the outset, it is stated authoritatively that destructive normalisation is lossless, which it is not: any alteration to data is lossy, irrespective of the probability that it will be audible and of some people wanting to play redefinition by claiming that something can be effectively lossless.* Then later, someone implies that RG cannot normalise an album while maintaining dynamic differences among tracks, despite numerous posts immediately prior discussing Album Gain, which exists for precisely that purpose.

There are probably others, but I got put off quickly by (what I saw as) the concentration of misguided/ing information and the general lack of direction.

* Nick.C appreciates this and accordingly is honest with words, as shown by lossyWAV et al.
Go to the top of the page
+Quote Post
Engelsstaub
post Jul 18 2012, 16:49
Post #10





Group: Members
Posts: 545
Joined: 16-February 10
Member No.: 78200



I appreciate that honesty in wording and efforts to maintain honest wording and precision. I'm often sloppy in my wording (as I've demonstrated in this thread alone!) but I don't mind correction. I just remind myself that this forum must strive to maintain certain standards that seem to be regrettably absent elsewhere in cyberspace.

...but anyway: I was under the impression that some of my previous vinyl rips were in need of being re-recorded at closer to peak levels to obtain "better" or "optimal" quality. If I (or a younger person with better ears) can not discern a loss in quality then it should be satisfactory and "just as good" for my purposes.


--------------------
The Loudness War is over. Now it's a hopeless occupation.
Go to the top of the page
+Quote Post
AndyH-ha
post Jul 18 2012, 20:37
Post #11





Group: Members
Posts: 2192
Joined: 31-August 05
Member No.: 24222



Various "editing" changes can make differences in the peak level. That could result in peaks going above 0dBfs. If you are working in floating point this isn't too awful, it will be taken care of when you normalize. However, if you've already normalized, before the other changes, you will just have to do it again to bring the level back down. Normalizing is best done immediately before converting to 16 bit.
Go to the top of the page
+Quote Post
Porcus
post Jul 18 2012, 23:11
Post #12





Group: Members
Posts: 1779
Joined: 30-November 06
Member No.: 38207



QUOTE (Engelsstaub @ Jul 18 2012, 17:49) *
I was under the impression that some of my previous vinyl rips were in need of being re-recorded at closer to peak levels to obtain "better" or "optimal" quality. If I (or a younger person with better ears) can not discern a loss in quality then it should be satisfactory and "just as good" for my purposes.


You report peaks at -3 dB. Which is about half a bit wasted, and that half a bit is probably filled with noise anyway. http://en.wikipedia.org/wiki/Dynamic_range#cite_ref-18 suggests you won't get more than 70 dB dynamics into (and thus, not out of) an LP groove, and that's about 12 bits. So if they sound like you need to re-record them, then this isn't the reason why.

Now if it wasn't for the noise that makes the following a bit superfluous: The 'right thing to do', would be to record into somewhat more than 16 bits. Like, 24: eight more bits means that you have plus/minus four bits' worth of margin of error if you think you record at an album peak of about -24 dB. Then you do all the processing (crackle/pop removal and whatnot) in the digital domain, and then afterwards scan for peak and apply peak normalization to 0 dB. Probably there is nothing in the lowest 4-ish except noise introduced by your processing. Dither it down to 16 bits, et voilą.

You could very well be within 1 bit of that, and that's not much if that one and three more are basically noise.


Anyway, a ReplayGain scanner like foobar2000, writes ReplayGain tags only (no re-encoding). If you use e.g. dBpoweramp Music Converter, then there is a 'ReplayGain' which scans and tags, and a 'ReplayGain Apply' which applies the volume gain to the file (re-encoding your FLACs ... are you using lossless). If you are unsure how your application of choice does this, then just make a copy of a sample file, scan ReplayGain, and click OK if it asks you to commit the change; then use e.g. foobar2000 with foo_bitcompare to compare the audio of the original and the processed file. If whatever you used is merely a tagger, they will come out as bit-identical.

When fb2k has tagged a file (well, scan an album as an album, not individual tracks), you can view the RG values. What is Album Peak in your case?



(... that fraction-of-1 is digital amplitude, right? So 0.71 is about -3dB? Anyone?)


--------------------
One day in the Year of the Fox came a time remembered well
Go to the top of the page
+Quote Post
Engelsstaub
post Jul 19 2012, 09:39
Post #13





Group: Members
Posts: 545
Joined: 16-February 10
Member No.: 78200



Andy: Thanks. I guess I should have known that its best to normalize last. Especially when I need to declick and do other stuff to the files.

Porcus: I would have ideally liked to have recorded at 24 bits but my preamp's USB out is USB 1.1 protocol. (Pro-Ject Debut III USB) I plan to make necessary changes to my hardware in the near future but until I do I'm stuck with 16 bit...I wish I had known that before I purchased that TT. (I can use a RCA to headphone jack cable directly to my MacBook Pro's soundcard @ 24 bits but I have a feeling USB would be much "cleaner.")

Also I'm using iZotope RX 2 on OS X so Foobar's out for me. (I do have a Windows PC but it has issues that preclude me from wanting to use it for much.) If you're wondering about the album peak in the case of the album in my illustration, I scanned all of the tracks in iZotope RX and found it to be exactly -3dB. There was something closer to FS but upon inspection it turned out to be a "pop."


--------------------
The Loudness War is over. Now it's a hopeless occupation.
Go to the top of the page
+Quote Post
bandpass
post Jul 19 2012, 10:21
Post #14





Group: Members
Posts: 321
Joined: 3-August 08
From: UK
Member No.: 56644



Here's the first track of the "Black Triangle" 1983 Toshiba CD release of the Beatles' Abbey Road album, long regarded by some as the 'holy grail' version of the album. Note the levels, over 6dB down on the left channel:



In fact, many albums in the 80s were mastered at these sorts of levels and no-one complained. So I don't think you've much to worry about.
Go to the top of the page
+Quote Post
Porcus
post Jul 19 2012, 12:13
Post #15





Group: Members
Posts: 1779
Joined: 30-November 06
Member No.: 38207



QUOTE (Engelsstaub @ Jul 19 2012, 10:39) *
my preamp's USB out is USB 1.1 protocol. (Pro-Ject Debut III USB)


The turntable-with-preamp? It has a decent reputation at the price mark.

Your postings indicate that you have not done any volume adjustment at all, in which case the ProJect recorded your LPs with a peak at about -3 dB. That sounds to me like it has employed a reasonable volume for its ADC. No reason to change that, really.

I read that the ProJect's RIAA preamplification cannot be bypassed; that means that if you record by soundcard, it is only the (presumably) “easiest part” of the groove-to-digital processing that you replace. You cannot expect much improvement then. You might of course record through both and perform a listening test, but I would be (mildly) surprised if you get any “wow!” experience at equal volume. (Can the ProJect output to both RCA and USB simultaneously? Then you could timing-align them and ABX.)

The Ortofon OM5 is an entry-level pickup, so unless the sound clearly indicates that you should do the process over again, then I wouldn't re-record unless I had replaced the OM5 with something better. However ... the following is due to my lack of knowledge on the ProJect's internals, but I would be careful: as the ADC seems to process at a reasonable volume with the OM5, then how would it perform with a different pickup with a different output level? If it adjusts volume (... which I doubt, as I think it is a bad idea to implement), then nothing would change. But if it is simply set at the OM5's max out, then you don't want a pickup with higher output level (it could cause clipping). Your initial position was that 3 dB is wrong; actually, I'd guess that those 3 dB are really the ProJect's healthy margin of error.


I'd say ReplayGain it smile.gif

This post has been edited by Porcus: Jul 19 2012, 12:18


--------------------
One day in the Year of the Fox came a time remembered well
Go to the top of the page
+Quote Post
Engelsstaub
post Jul 19 2012, 14:28
Post #16





Group: Members
Posts: 545
Joined: 16-February 10
Member No.: 78200



bandpass: I guess I never really thought of it that way. I've seen/heard plenty of examples of CDs mastered like that and find them far preferable to what they are doing to modern pressings on the format now. If it's too low we can always reach for the volume, but we can't fix this clipped/0 dBFS stuff that's getting pressed today.

Porcus: Yeah, that's the one. It's overall a decent TT. It sacrifices some flexibility for convenience. If the wow and flutter stays low I may just keep it around and upgrade the cart to a Ortofon Blue or something not too expensive. The cartridge that comes with it sounds decent to my ears but it's possible I just don't know any better.

I've never tried to output from the RCAs and the USB simultaneously. Most of my records range from approximately -3 to minus -6 down from FS. There's a few, especially 2xLPs that are cut a little louder and can't be decently recorded until I acquire some additional analog hardware to go between the pre and the computer. ...but that's life.


--------------------
The Loudness War is over. Now it's a hopeless occupation.
Go to the top of the page
+Quote Post
Arnold B. Kruege...
post Jul 27 2012, 17:19
Post #17





Group: Members
Posts: 3536
Joined: 29-October 08
From: USA, 48236
Member No.: 61311



QUOTE (Engelsstaub @ Jul 18 2012, 06:07) *
1. Is there any reason why applying gain would effect the quality of the original recording in the resulting product? (Would it have just been better to get the level set closer in the first place tongue.gif ?) I know that reducing the volume is "losing bit depth," as I've read this from members in older threads while searching earlier.


Consider the context. The source object (vinyl) has about 12 bits of resolution. Your editing environment has from 16 to 24 bits of resolution. The weakest link is obvious. As a rule of thumb, if there are about 3 bits of difference, the difference is less than a tenth of a dB which is deep into audibly negligible.

QUOTE
Is there a reduction in bit depth (or perceivable sound quality) when increasing the volume when using a quality program at the upsampled bit rate?


As long as you haven't lost usable resolution by recording the track at too low of a volume originally, no. If you are adding more than 20 dB of gain, you really should redo the origional transcription.

QUOTE
2. Should the gain be applied before or after the editing (or does it even matter) assuming that number one isn't a boneheaded way to approach this with respect to quality?


In general, if anything makes a difference and it usually doesn't, the most important thing is getting the signal levels up, but not so far up that anything you subsequently do causes digital clipping. I like to see peaks within 3 to 10 dB of FS at any step in the processing.

It appears that you are concerned about gain changes on the order of 3 dB which should always end up being moot, even with average software.
Go to the top of the page
+Quote Post
Engelsstaub
post Jul 27 2012, 22:29
Post #18





Group: Members
Posts: 545
Joined: 16-February 10
Member No.: 78200



Thanks, Arnold. Your reply was valuably helpful and informative to me. smile.gif

I plan on acquiring a bit more advanced hardware in the future...so I'll likely just do recordings at a higher bit-depth then (probably 24/88.2 but IDK.) I'm however convinced that 16-bit is sufficient and am comfortable with it currently (since CD-R's the target anyway regardless of what I archive as.)


--------------------
The Loudness War is over. Now it's a hopeless occupation.
Go to the top of the page
+Quote Post

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: 20th April 2014 - 08:10