change dither to none? in quality settings?

Audacity Help Forum Windows
21

I don’t know how to explain more clearly than I already have…
And I’ve just had the same happen with a completely different file…

Open the original 16bit/44.1 file.
Highlight the file with the cursor and increase speed +0.1%, go to export and select FLAC…
Dither is SHAPED.
Repeat this except on export save as WAV…
Both exported WAV and FLAC are 16bit / 44.1.
WAV has louder hiss than the FLAC in the silence before the music…
I can hear it in the 3 different programmes I listened with…

22

How? Drag it into an open project? Open Audacity and select “File > Import > Audio”? Some other way?

When the audio has been imported, in the panel on the left side of the track, does it say that it is 16 bit, 24 bit or 32 bit float?
Is it a mono or stereo track?

How? Using the Change Speed effect? or the Transcription Toolbar? or the “Sliding Time Scale / Pitch Shift” effect? Some other way?

What file name are you entering? Is it a new unique file name or are you overwriting an existing file?

That’s in “Edit > Preferences > Quality” ?

With the same file that you imported in step 1? (what was “step 1”?)

When played how? In what program?

If you import the files back into Audacity, do they sound the same?

What programs?

I can’t see your computer or what you are pressing, so “step by step” really does need to be click by click and key by key if I am to be able to reproduce the same result.

23

*Open Audacity - File - Open - Double click track
Left panel says Stereo 32 bit float.

*Highlight track with cursor from right to left - select Effect - Change speed - in box make % change 0.1 and standard vinyl RPM n/a and n/a, click OK and speed changes…
*File - Export (doesn’t matter what name you make it same results, even if you leave the original name and just add.wav) eg. I just used the name “+0.1 increase.wav”, then click save, file will save…
*yes Dither is still set to Shaped in Edit - Preferences - Quality.

Repeat exactly as above but save as FLAC not WAV. Both outputs are definitely 2stereo 16bit/44.1.

Playback in Audacity, Adobe Audition 1.5 and GoldWave all have the louder hiss in the WAV.

24

Try this:

  1. Open Audacity.
  2. Generate menu > Silence. Generate 6 seconds of silence.
  3. Export as silence1.flac (Click the “Options” button to ensure that the FLAC exporter is set to 16 bit).
  4. Export as silence2.wav (16 bit Microsoft PCM WAV)
  5. Play the exported files - do you hear a difference in the amount of hiss?
  6. Close and restart Audacity.
  7. Import silence1.flac and silence2.wav into Audacity.
  8. Ctrl+A (select all)
  9. Effect > Amplify. Apply the “Amplify” effect with the default settings.
    Do both tracks show the same amount of noise?
25

Hi,

Going through the process you listed produces 2 files which seem to have the same amount of hiss to me…, the WAV and FLAC seem to be the same…

However I just downloaded Audacity on a completely different computer (PC not my laptop), and doing the exact process’ I have previously described
also produced the WAV with more hiss than the FLAC.
I have notcied the hiss in the WAV doesn’t seem quite as loud on the PC as my laptop, it’s definitely quiter on the PC, however still more than the FLAC, I then transferred the files made on my PC to my laptop and when played on my laptop the hiss in the WAV produced on my PC is exactly as loud as the WAV produced on my laptop, so the loudness of the hiss seems different whether played on my laptop or PC, however on both PC and laptop the WAV hiss is still louder than the FLAC.

I’m listening full volume with earphones…
Here’s the first 3 seconds of the FLAC:
http://www.4shared.com/file/eyy4msHP/01speed_increase_exported_SHAP.html

Here’s the first 3 seconds of the WAV:
http://www.4shared.com/music/JW_0dyqh/01_speed_increase_exported_SHA.html

26

So it’s over to you. Tell me how to reproduce the difference that you are hearing,
If it requires importing a file, please upload that file somewhere on the Internet so that I can download it and reproduce your results.

27

Hi,
The process is as I posted 2 posts ago, I think I have included every detail…
I got the same results with 2 other songs I saved from an album, seems to be that as long as there is silence before the track the WAV will have louder hiss…
For example, it happens with this original file:
http://www.sendspace.com/file/xxwkqs

*Open Audacity - File - Open - Double click track
Left panel says Stereo 32 bit float.

*Highlight track with cursor from right to left - select Effect - Change speed - in box make % change 0.1 and standard vinyl RPM n/a and n/a, click OK and speed changes…
*File - Export (doesn’t matter what name you make it same results, even if you leave the original name and just add.wav) eg. I just used the name “+0.1 increase.wav”, then click save, file will save…
*yes Dither is still set to Shaped in Edit - Preferences - Quality.

Repeat exactly as above but save as FLAC not WAV. Both outputs are definitely 2stereo 16bit/44.1.

Playback in Audacity, Adobe Audition 1.5 and GoldWave all have the louder hiss in the WAV.

28

I don’t have an account with 4shared but it won’t let me download the file without.
Could you upload the file somewhere that registering is not required (for example sendspace.com) or alternatively is it possible to reproduce the problem using generated tones?

29

Hi,
I’ve replaced the link with a SendSpace link.

30

Thanks. Got it.

Steps:

  1. Launch Audacity (new project)
  2. Preferences > Quality:
    Default sample rate: 44100
    Default sample format: 32 bit float
    High quality conversion: High quality / shaped.
  3. Preferences > Import export:
    Read uncompressed directly … (faster)
  4. File > Import > Audio: The Cure - 01 - Pictures of You.flac
  5. Ctrl+A (select all)
  6. Effect > Change Speed: Percent change = 0.1
  7. File > Export: File format Flac (16 bit, level 5), Name: “flack-test”
  8. File > Export: File format WAV (Microsoft PCM signed 16 bit), Name: “wav-test”
  9. File > Close: Save Changes = No (Project closes and a new project window opens.
  10. File > Import > Audio: Select “flac-test.flac” and “wav-test.wav” (the two files are imported).
  11. Select the first 2 seconds in both tracks.
  12. Ctrl+T (trim)
  13. Select the flac-test track and “Export Selection” as: File type: other uncompressed format, WAV (Microsoft), 32 bit float, name: “flack-test-export.wav”
  14. Select the wav-test track and “Export Selection” as: File type: other uncompressed format, WAV (Microsoft), 32 bit float, name: “wav-test-export.wav”
    (32 bit float export is bit for bit identical to the data in the Audacity project).

These are the two files:


As expected, they are not bit-for-bit identical (because dither includes a random element), but as far as I can tell they are otherwise the same - no difference in the amount of hiss. The peak level for the first 0.5 seconds in both tracks is -72.2 dB (as expected for 16 bit shaped dither).

So what did I do different? How do I reproduce your results?

31

Hi,
Well…
I just downloaded your 2 files, and the WAV has a lot more hiss than the FLAC!, played in Audacity, Adobe 1.5 and GoldWave… (earphones with volume right up), the FLAC has NO hiss, the WAV has VERY CLEAR hiss…
I wonder what this could be? It’s only happening with the dither shaped WAV’s, the exact same process with dither set to NONE leaves NO hiss - so it’s not that this happens with every WAV file I play… I just converted the original FLAC to WAV with dbpoweramp, and there’s no hiss in the WAV… I have other WAV’s on my HD and no hiss…
All I can say is I’m only finding hiss with WAV’s that have been through Dither Shaped Audacity…
I really don’t know where to go from here!, because I have no idea what it could be! (I’m sure you’ve tried earphones with volume right up???)

32

How very peculiar. :open_mouth:

  1. Import both files into Audacity.
  2. Select the first 1 second in both tracks.
  3. Apply the “Amplify” effect with default settings. (Obviously the first 1 second in both tracks is being amplified by exactly the same amount, which in this case will be +50 dB.
  4. Compare the level in the first 1 second - do you agree that it is the same in both tracks?
33

Hi,
When I go to File-Import your FLAC Audacity says it can not find FFMPEG, however your FLAC will open with File-Open.
My other FLACS will open with File-Import, just having the problem with the one you sent me…

34

After solving the case of the odd Aiff file, the next thrilling adventure looms ahead, the “strange case of Mr Flac”.
I must admit that I am baffled too.
It seems that the wave file isn’t shaped at all - just plain white noise.
The two files have apparently the same sample values but differently distributed.

35

Weird indeed.
The exported WAV file has got “Triangle” dither when it should have “Shaped” dither.
I wonder when that bug crept in.

I’ll raise this with the developers.

36

It’s only happening when exporting stereo WAV files, not mono WAV files.

37

I’ve reported the issue to the developers.

This bug has been present since at least the 2.0.0 release. Obviously not many people listen to silence with volume cranked all the way up :wink:

38

Most definitely not required to listen to silence with the volume all the way up to notice it…
I can hear that the WAV has more hiss than the FLAC with headphones and my laptop volume not even half way up, in fact probably less than 1/3 way up, below even average listening volume…

39

You’re right, the dither noise in 16 bit stereo WAV files is much noisier than it should be.

40

Good news - one of the developers has found the cause of the problem and has created a fix for it.
The bad news is that the fix may be too late to get into the Audacity 2.0.4 release, but if not it will certainly be in 2.0.5.
If the fix does not make it into 2.0.4 then I’d highly recommend changing the dither setting to “Triangle”, which is almost as quiet as “Shaped” and is equally good at preventing harmonic distortion.

Thanks bomber1978 for reporting this problem and for your persistence (in spite of me telling you that it was nothing to worry about :blush: )

Surprisingly this problem has existed for at least 4 years. I’ve looked at this before, but it is easily missed when testing because it does not occur with mono files, it does not occur when dither is applied within a project, it does not occur with FLAC export, it does not occur with other types of dither. Also it is expected that “some” noise should be created by dither, and when testing with “real world” audio recordings it is difficult to tell that the wrong type of noise is being added. It only occurs when exporting stereo files , but that is of course a common case, so is very important.