Linux DAW - January 2008 roundup

[Oren]

As far as the selection of Linux tools for digital audio work is concerned, my Athlon/Asus machine with Ubuntu Studio as the operating system tends to favour the more full-featured offerings.
Ardour, Rosegarden, Jamin, ZynAddSubFX, and Hydrogen will interface reliably with JACK and work together seamlessly in all the various possible combinations. These are the applications I'll use for writing, sound synthesis, audio manipulation, mixing, and mastering.

The other (less capable) applications seem to have a funkier vibe and are more interesting to me, but their performance, at least on Ubuntu Studio, is quirky and unreliable, particularly when used in combination with JACK.

What I need to find now is: 1. a tool that will measure the RMS levels of a recording (Meterbridge will 
                                                not do this)               
                                                 
                                      2. an application that will convert audio files from/to the various formats the
                                                    way winLAME does in Windows.

[kara]

Converting audio formats under linux is mainly a question of having the codecs installed on your machine for the different formats.
Once you have those, a couple of scripts can help you
Here you have some examples : http://wiki.linuxquestions.org/wiki/Audio_conversion

k

As far as the selection of Linux tools for digital audio work is concerned, my Athlon/Asus machine with Ubuntu Studio as the operating system tends to favour the more full-featured offerings.
Ardour, Rosegarden, Jamin, ZynAddSubFX, and Hydrogen will interface reliably with JACK and work together seamlessly in all the various possible combinations. These are the applications I'll use for writing, sound synthesis, audio manipulation, mixing, and mastering.

The other (less capable) applications seem to have a funkier vibe and are more interesting to me, but their performance, at least on Ubuntu Studio, is quirky and unreliable, particularly when used in combination with JACK.

What I need to find now is: 1. a tool that will measure the RMS levels of a recording (Meterbridge will 
                                                not do this)               
                                                
                                      2. an application that will convert audio files from/to the various formats the
                                                    way winLAME does in Windows.

[folderol]

@Oren
What do you mean by 'measure' and what do you mean by 'RMS' ?

Meterbridge has quite a number of different display options. The one I use is VU, which as it suggests give a very good approximation of real analog VU meters. You can also send it a 'sensitivity' value to change what it regards as 0dB.

[Oren]

RMS is a term I normally associate with wattage output to speakers, and have never encountered its use in audio production until Martin and rharv began using it as a measure of functional "loudness" in a mastered audio file.

Being old-school, I just boost the levels until sound degradation occurs, then back off a notch. But I can't talk numbers with these technically advanced dudes - until I get me a tried-and-true RMS meter.

 

[folderol]

Ah yes. I think R.M.S. in audio terms is often used interchangably with VU (volume units). In theory you can't have an RMS value for a varying amplitude signal If I remember my electronics correctly VU measurement systems were developed to get a mean figure that corresponds to the loudness. If a maximum non-clipping signal is referenced as 0dB then you should be able to get relative RMS values from that.


... of course it's quite possible the other guys are talking about something completely different

[kara]

The exact description of RMS is : The RMS term expresses what value an existing AC-signal should have - had it been a DC-signal - to develop the same amount of energy as the DC-signal would for the given configuration. In other words, the RMS value is a special kind of mathematical average value which is directly related to the energy contents of the sound.

So, basicly when you use a compressor on your tracks, you're not only handling the peak levels of your track but you're allso augmenting the RMS of the track.
Why are compressors so popular in modern music ?
The perceived loudness is a function of the frequency and the sound level, but also a function of the sound duration. Sounds of short duration are perceived to be of a lower level than steady continuous sound of the same level.
Now there are 2 wyas of express this.
1. The LEQ : to keep it simple and not playing with maths, the LEQ is the linear average of the measured levels.
2. The RMS : RMS value expresses a weighted average where more recent events have more weight than older events.

As you can see , they express allmost the same thing but in a different way. When I explain to non-musician I allways describe it as, the LEQ is what you hear, the RMS is what you feel...




k

[Oren]

Thanks Kara! Sounds about right 

Now for a meter in Linux that will measure RMS so I can communicate a number to my more technically adept brothers and sisters. I'm sure one will show up eventually...

[Oren]

Converting audio formats under linux is mainly a question of having the codecs installed on your machine for the different formats.
Once you have those, a couple of scripts can help you
Here you have some examples : http://wiki.linuxquestions.org/wiki/Audio_conversion
k

What I need to find now is an application that will convert audio files from/to the various formats the way winLAME does in Windows.

"Sound Converter" is the all-in-one Linux audio file format converter.
 Reads all formats. Writes .wav .flac .ogg .mp3 - constant bit-rate and variable bit-rate.

http://soundconverter.berlios.de/              c'est ca

[kara]

A litle link to the side, perhaps 

k

[Oren]

Good news!

Audacity will work effectively in Ubuntu studio in two ways:
...........with JACK turned off, it interfaces with ALSA nicely
...........or with JACK's realtime mode switched off.

Because Audacity was designed as a cross-platform tool, its JACK connection must be through a device called the "portaudio-v19" interface, and is consequently not a full-featured JACK client.

It's a pleasure to have Audacity back in service because it's the only open-source software with which I'm really familiar.

[kara]

Good News Oren 

I've updates my system yesterday to the latest release of Debian, called 'Etch' or version 4.0r3. The update went smooth with out any problem.
On application level there are no big updates but there is a new alsa and jack package included.
I've noticed that with the new version, jack with freebob and my m-audio firewire box takes 5% less CPU ! Propably due at optimisation they've done.

Since I'm completly up to date and operational, it's 'end of technology' and 'back to music' now 

k

[Oren]

I've updates my system yesterday to the latest release of Debian, called 'Etch' or version 4.0r3.
....there is a new alsa and jack package included.
I've noticed that with the new version, jack with freebob and my m-audio firewire box takes 5% less CPU !  ....'back to music' now 

Kara,

Good job of the Linux O/S and DAW.

I'm hoping Ubuntu will use the  Debian "Etch" version to include the new ALSA and JACK package in an upgrade to the current release "Gutsy Gibbon".

In many ways the Linux audio system reminds me of Buzz Machines, with JACK/ALSA being the "Master", and all of the applications being the "machines". Anything done to improve JACK/ALSA will enhance the performance of all the applications.

Looking forward to your next song,

Oren.

[Wyatt]

Good news!

I'm glad to hear things are smoothing out some for you.

You really took on something here. Keep up the good work.

Wyatt

[kara]

I've updates my system yesterday to the latest release of Debian, called 'Etch' or version 4.0r3.
....there is a new alsa and jack package included.
I've noticed that with the new version, jack with freebob and my m-audio firewire box takes 5% less CPU !  ....'back to music' now 

Kara,

Good job of the Linux O/S and DAW.

I'm hoping Ubuntu will use the  Debian "Etch" version to include the new ALSA and JACK package in an upgrade to the current release "Gutsy Gibbon".

In many ways the Linux audio system reminds me of Buzz Machines, with JACK/ALSA being the "Master", and all of the applications being the "machines". Anything done to improve JACK/ALSA will enhance the performance of all the applications.

Looking forward to your next song,

Oren.

Well, to upgrade to Etch, you'll have to modify the package resource of synaptic.
I guess that it is set to ubuntu at the moment like mine was set to 64studio.
Ubuntu, 64 studio and a couple of other distros decide themself when they integrate the new debian modules. 64studio for example is at the moment been frozen at version 2.0.
By changing the repository for the package, you actually accept to upgrade to the latest official debian version, which is the core of a lot of other distros.

The choice is not without risk as explained on the debian site.
SInce i have a good backup of a working system, I decided to take the risk, and it went without any problems

and BTW we are working on that new song

k

[folderol]

The only thing you really need to watch out for when using the etch repositories is to make sure you don't upgrade the kernel with a non-RT one