Audacity Forum

Hi everyone;

First time posting here (also my first time posting outside Spain where I am from, so excuse my english please).
I have been reading a lot about this matter but I still have some questions before continuing heavily ripping my vinyl collection. Also I could not find any post with my "problem".

My problem is that I record vinyl quite nicely and clearly ant 24Bit 96Khz with audacity exporting WAV 24Bit 96 direct with no dittering, but when I go to burn into a CD-Audio (using MAc os and Toast). I find out that the final CD-a recording has add backround noise and lose quality... The difference is clear (making blind test also my girlfriend cuold notice what sounds better). I have searched in internet and everybody more or less agree that there should be no losing quality (nor audible) in this process.

The I go with the questions:
(This maybe should be in another threat or even different forum so excuse ... but If I find an "expert" is maybe my only chance to clarify myself).

Obtaining CD-audio:
1-. Should I better record / export to WAV 16Bit 44Khz and then burn to avoid toast making conversion?
2-. Is there anyone that have a "refined" technique that can share with me or I have a hardware problem?


¿What could be the best way to get the music at 24bit 96Khz out of the computer an play it in an "only music system"? (without turning on a tv or a computer...):
1-. Can I burn data (DVD or CD) as 24bit 96Khz WAV and make it playable in a DVD player as it were a classic CD? Is there any method?
2-. If I have the right DVD player with (DVD-Audio reading features) and create DVD-audio (instead of data) can I play tracks (again without the tv..), does anyone have created a DVD-audio at 24bit 96khz and succesfully played as it were a normal CD?

Thank you very much in advance.

Normal audio CDs are always 16 bit, 4100 Hz stereo PCM. This is the standard for audio CDs http://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio

My advice would be:
1) Ensure that you are using the current version of Audacity (2.0.5). Look in the "Help menu > About Audacity" for the version number. If you have an older version, get the current version from here: http://audacityteam.org/download/ (this is important due to recent improvements).

2) Go to "Edit > Preferences > Quality" and set the options like this:


3) If you have separate settings for your sound card, try each of them to see which works best (Note: it is not always the highest settings that sound best).

4) Set your recording level so that the highest peaks come to around half the track height - it is OK if they go a little higher, but should never go all the way to the top or bottom of the track.

5) Before you export, Normalize to -0.5 or -1 dB.(most CD players add a little distortion as the signal gets very close to 0 dB - even really good CD players).

6) Trim the start and end of the recording very carefully to remove silence from the start and end of the recording. If you want a bit of silence between tracks, use your CD burning software to insert pauses. This will ensure that gaps between tracks are absolutely silent.

7) Export in 16-bit WAV format (the default export format).

Platform specific settings:
If you are on a Linux machine, use ALSA as host and the "hw" options for recording and playback devices in the device toolbar. This will avoid any unnecessary format conversions in PulseAudio.
There may be platform specific "best settings" for Windows and Mac OSX (I use Linux).

Hi Steve;

Many thanks for your help, it actually worked perfectly;
No more noisy sound in the backround.
It seems that downsamplig from 24bit 96Khz to cd audio via toast (I use Mac osx) added extra noise or " errors" ruining the recording...
What is the key point? I guess doing the shaped exporting via Audacity (not leaving any work to the burning program)... correct?

More questions Steve:
Dou you recommend me better this way that for example:
recording in 32bits 192Khz (my sound card supports 32bits 96Khz.) and then exporting to cd quality or even to 24bits 96Khz wav? Do you personally recommend me to forget about getting wav DVD-A at 24/96Khz? I have plenty of space in my hard drive, and very easily i could get a pioner dvd 24 bits...
But does it worth it? Does It make any difference?

Steve more help, I normalized to -0.5 but I dont knows how actually works / act on the "waves". less -0.5 is more normalizing?, anyway I trusted and followed your recomendation.

Thanks Again!

nachezman wrote:Dou you recommend me better this way that for example:
recording in 32bits 192Khz (my sound card supports 32bits 96Khz.) and then exporting to cd quality or even to 24bits 96Khz wav?

There is no point in recording higher than 96 kHz. Doing so will increase the file size but adds no additional audio information and data errors become more likely at higher sample rates.
You may find that there is a very subtle difference between recording 44100, 48000, or 96000 Hz, but higher does not necessarily mean better. You are most likely to find no audible difference at all.

A bit about the theory behind this.
The sample rate governs the highest frequency that can be represented. The absolute maximum frequency that can be represented is half of the sample rate (known as the "Nyquist frequency"). In practice, the highest frequency that can be represented is a little less than the Nyquist frequency, but with modern digital filtering technology they can get very close to the theoretical maximum. The highest frequency that human hearing is capable of is usually quoted as 20000 Hz, though this figure refers to "perfect" hearing for a person under 18. The upper limit declines with age, so a more realistic figure for an adult with good hearing is more likely to be 16000 Hz or less. Thus 44100 Hz sample rate is just enough for the full frequency range that young people with perfect hearing can hear, and is more than enough for the rest of us.

Analogue to digital converters generally have "native" sample rates that the hardware is designed to work at. This may be just one specific sample rate, or a few different sample rates. The most common "standard" sample rates for audio are 44100 Hz and 48000 Hz. Recording at a non-standard sample rate is achieved by converting the sample rate from that implemented in hardware to the required sample rate. Conversion is usually pretty good quality, but can be avoided altogether if everything is working at the same sample rate.

Audio CDs are always 44100 Hz, so if the recording is not 44100 Hz sample rate, then it has to be converted.
For best quality, the number of conversions should be kept to a minimum. Thus, if the hardware runs at 48000 Hz, then you can either record at 44100 Hz (one conversion) and stay at 44100 for the rest of the process, or record at 48000 Hz and convert once to 44100 Hz at some point before burning to CD. The sample rate conversion in Audacity 2.0.5 is very high quality, so if recording at 48000 it is generally best to export from Audacity as 44100 Hz (Audacity handling the conversion) rather than exporting at 48000 and using the CD burning software to do the conversion.

In theory there is no benefit to using sample rates greater than 44100 Hz. In practice, the best results are likely to be either, recording at 44100, or recording at 48000 or 96000 and changing the "Project Rate" (lower left corner of the main Audacity window) to 44100 before exporting. Most likely there will be no noticeable difference between these options other than file size, in which case recording at 44100 Hz is better (less demanding on computer resources).



Bit depth:
32 bit float is better for processing, so this should normally be the selected format for recording. The sound card will then supply the highest format that the system (as a whole) supports.
For CD, the exported file should be 16 bit as this is required for audio CDs.
For "perfect" quality back-up copies, the audio may be exported as 32 bit float WAV. Files in this format will be double the size of normal 16 bit WAV but will be very slightly "cleaner" in that it is an exact copy of the data in Audacity (not converted).
16 bit WAV (or Flac) is usually good enough for back-up copies, but 32 bit float gives a perfect copy. For this option you need to select "other uncompressed formats" as the file type. See these links:
http://manual.audacityteam.org/o/man/fi ... ialog.html
http://manual.audacityteam.org/o/man/wa ... tions.html

Hi Steve;

I am beggining to settle down my ideas (if that make sense in english), now I can proceed knowing what I am doing.

Many thanks for your help Steve!.

steve wrote:In theory there is no benefit to using sample rates greater than 44100 Hz.

This article might be interesting for nachezman to read: http://xiph.org/~xiphmont/demo/neil-young.html . Some people still claim though that they hear subtly better sound recording and storing at 192000 Hz.

Can we really believe though that $3 sound chips in a cheap laptop will transparently oversample? I wonder since most such chips claim to support 192000 Hz if they might not be better recording at that rate?


Gale

Gale Andrews wrote:Some people still claim though that they hear subtly better sound recording and storing at 192000 Hz.

As in my previous post, an audio device may perform better or worse at some other sample rate, though usually the difference in quality is undetectable unless the sample rate is so high that there are "dropouts" (bits of audio missing). Quality differences at sample rates of 44100 Hz or higher are a matter of implementation than any intrinsic benefit of one rate compared with another.

Gale Andrews wrote:Can we really believe though that $3 sound chips in a cheap laptop will transparently oversample? I wonder since most such chips claim to support 192000 Hz if they might not be better recording at that rate?

On my machine with the on-board sound card, the sound quality is noticeably worse at 192,000 Hz than at 44100 or 48000 Hz. At 192kHz there is a substantial amount of additional noise above 13 kHz which is not present at "more sensible" sample rates. Then again, the sound quality is pretty atrocious at any sample rate.

My 2c based on practical experience (hundred of LPs digitized)

I record and edit with Audacity set at it's default 32-bit float 44.1kHz

I export to 16-bit 44.1kHz PCM stereo (Red Book CD standard).

I have export dithering for down-sampling on export set to Triangular

I burn CDs for playing on my Rega Planet hi-fi CD deck - and I import the 16-bit WAVs into my Cocktail Audio X30 "jukebox" player.

I listen to these on high-end electrostatic speakers QUAD ESL-57 and on studio quality Sennheiser headphones. I find the sound produced truly excellent well more than acceptable for real-life hi-fi listening.

WC

P.S. I use third-party software to remove clicks and pops (ClickRepair - see: http://forum.audacityteam.org/viewtopic.php?f=28&t=1994) iy costs a little but produces excellent results for me.

waxcylinder wrote:I have export dithering for down-sampling on export set to Triangular

In the past I recommended using "Triangle" rather than the default "Shaped" dither. In old versions of Audacity the Triangle dither would produce better results for stereo tracks, However, there was recently (Audacity 2.0.4? somewhere around there) a significant improvement to the "Shaped" dither in Audacity. My recommendation for Audacity 2.0.5 (and later) is to use the default "Shaped" dither as this gives the best quality.

waxcylinder will be pleased to know that this does not mean that he needs to re-record his vinyl collection. Triangle dither worked pretty well in old versions of Audacity and is exactly the same in the current version. The difference is that the current version improves the shaped dither for stereo file export and gives (even) better quality than triangle dither. Note: the quality difference between different dither types, or even using no dither, is rather subtle - we are looking at the difference between "very good" and "best" where "shaped" is (now) "best".

steve wrote:there was recently (Audacity 2.0.4? somewhere around there) a significant improvement to the "Shaped" dither in Audacity. My recommendation for Audacity 2.0.5 (and later) is to use the default "Shaped" dither as this gives the best quality.

The fix was in 2.0.5 release (the bug did not affect FLAC or mono files in any formts):
http://wiki.audacityteam.org/wiki/Relea ... #Bug_fixes .


Gale