Author Archives: TedS

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Upgrading the New LTS version of Ubuntu-Studio

Ubuntu, has a versioning release sytem that accommodates bleeding edge users and users that are seeking stability.  Ubuntu-Studio follows this scheme.

The various releases are kept track of by a Major release number – the latest being 16, a minor release number, and a point release number in the format:  16.04.1  The major releases have a code name, 16. is Xenial Xerus, often just referred to Xenial.

There are generally substantial changes between major releases.  All the new stuff gets beta tested and tossed out into the world.  A release like 16.01.0 will likely have some hiccups because there are many things that have changed, and the changes do not always play nice with each other.

Because users who have production systems cannot track the “latest and greatest”, Ubuntu has established a “Long Term Release” based upon even major release numbers.  Major release 16 contains a Long Term Release.  Because the first several point releases are cleaning up incompatibilities, bugs and mistakes, it would be inadvisable to make an early major release with a low point release the LTS.  The Ubuntu folks have figured that by the fourth point release the new version has settled down enough to be stable.  So version 16.04  (and every .04 release of an even major release will become an LTS)  To see the support status of the Ubuntu-Studio operating system and applications simply enter
$ ubuntu-support-status at the comand line.  The end of life status for Ubuntu releases determines when they no longer get updates.

When Ubuntu and Ubuntu-Studio 16.04 (without the.1) was released, it was very cool, but as all sofware, it still had bugs that had not been found or completely squashed.  It may not have had the user interface completely resolved.  Only when  Ubuntu-Studio 16.04.1 came out does it become the LTS edition – Ubuntu-Studio 16.04.1 LTS.  Ubuntu-Studio 16.04.1 LTS was released July 21, 2016.  Updates to this version are intended to be focused on bug fixes, substantial performance improvements, etc.  There are rarely new applications or significant changes to the way it operates updated.  LTS versions are supported for five years, and other versions for only nine months.

LTS releases are what you build production machines from.  You want to turn off  automatic updates because you really don’t want to come in in the morning to find your workstation no longer works with the program you need to use because it was “updated” overnight. To update an LTS release, simply issue $ sudo apt-get update && sudo apt-get upgrade.

There are two other versions of “apt-get upgrade“,  the “dist-upgrade”, which is pretty safe in that it tries to upgrade every package in the package list, but will avoid any upgrades which require deleting a library or other possible dependency for another program.  There is also “full upgrade” which takes a more aggressive stance, and updates as many packages as possible without breaking dependencies.  In a production machine, I recommend only doing upgrades when you are physically at the machine where you can reboot it or fix whatever might stop working.

As I mentioned before, an LTS release will not get any new packages, but will upgrade all those that have been installed.  There is one notable exception.  This exception is “backports”.  Backports come in at least two groups.  Ubuntu backports are pretty well tested and you might consider using them to fix a broken or buggy driver, or to get something you really need working better.  By enabling the Ubuntu Backports repository (enabled by default) and installing from there opens you to some risk in a production environment, but it will probably work.

There are also manual backports where you build a package from a later edition of Ubuntu Studio to get some additional functionality.  Manual backports are for the daring and not for a production environment.

There are many different use conditions for Ubuntu-Studio, so you should plan carefully to determine what upgrade strategy to follow.  Do you want an appliance that will keep doing the same thing, year after year?  Is it your toolbox that needs to keep sharp?  It is a machine that lives on the internet and needs the latest security patches?  Is it on a closed network that is pretty safe from intrusion.  (Don’t forget flash drives, at my station we had a virus travel through several unconnected machines by the flashdrives in our “sneaker net”)

For anything you do with Rivendell, it is essential that you maintain a stable working environment.  Starting with a Ubuntu-Studio LTS distribution is an important place to start.  Locking down the upgrade process is one way to do that.  Opening it up only when prepared for a failure is a good strategy.  You really don’t want to have Rivendell go down without a plan to stay on the air.  Working out a plan to include security updates on a regular basis is also important.


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Nice demo of Rivendell with StereoTool

StereoTool is a very competent Jack enabled Audio Processor / FM stereo / RDS  Generator that runs on a decent 64Bit PC with a 192 kHz sample rate sound card.  Here is a YouTube demo of Rivendell feeding StereoTool through Jack. You can see the components working, and then the setup in KXstudio Catia patchbay.

RIVENDELL + STEREO TOOL

Nice! Where else can you get a complete radio station in a box?  Just add transmitter and antenna.


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Ubuntu-Studio vs DreamStudio

update! 3/2016

DreamStudio is no longer a complete distro.  It is now a package of applications available for Windows, Mac and Ubuntu and KXStudio.  It was last updated 10 months ago and is available on Sourceforge.  Dick MacInnes has let his domain names Celeum.com and dreamstudio.com expire.  I hope Dick is doing ok, with his, and his wife’s health issues.

 

Ubuntu-Studio is a very cool Linux distribution for folks who want to do audio, video, graphics, animation or other media production using open source software.  It uses a very utilitarian XFCE user interface.  This has the advantage of simplicity and lightweight overhead on processor chips, leaving muscle for DSP processes.  Ubuntu-Studio is a derivative of Ubuntu, a distribution for regular computing based upon  Debian, but much more user friendly.  Ubuntu-Studio is dependent only upon software with the same open source licenses that are available to regular Ubuntu.  As a result there are a bunch of programs, many of which are free, but not sufficiently liberally licensed, that are not natively included in the distribution, such as an .mp3 codec.  Many of these can be easily added, but are not available in the distribution itself Ubuntu-Studio

Ubuntu-Studio has the advantage of a large user base. Its release schedule is synchronized with its bigger brother Ubuntu.

DreamStudio from Celeum Technologies is a gorgeous media suite also based on Ubuntu, but it uses regular Ubuntu’s Unity user interface, which diehard Ubuntu users complain about, but once you learn the basics is incredibly intuitive, helping to get work done.

Dreamstudio was a complete operating system distribution or “distro”.  which you would install on a blank machine or set up as a dual boot.  The last version was based upon ubuntu 12.04LTS, which is quite old.  The new version is a suite of programs that you overlay on a regular Ubuntu installation. This makes some sense, as the low latency kernel is now standard in Ubuntu 14.04 and later, so there is no need to dicker with replacing the kernel.

I have not tried the new suite yet, and will try this out when I have another machine to set up.  There are applications in the suite that can be complicated to set up properly, and I am sure that it will be a lot easier to get them all playing together using DreamStudio than trying to install them one by one.  I am not sure what happens when you install DreamStudio on UbuntuStudio instead of Regular Ubuntu.DreamStudio

Celeum Technologies is a tiny company in Saskatchewan, Canada run by musician/technical guru Dick MacInnes.  DreamStudio has no open source rules, as does Ubuntu Studio including best of the pack open source, commercial and free or limited license software where it makes for a better workstation.

DreamStudio is not updated as often as Ubuntu and is intended to be installed on  Ubuntu Long Term Support (LTS) releases.  Sometimes the releases are delayed a bit from the Ubuntu LTS release.  This is because DreamStudio is a labor of love for Dick, and he works on it among other demands on his time (performance, family, running a small business).  The craft he does during the long Saskatchewan winter nights may very well be worth it if you need the additional features and pretty interface.

The audio workstations in Ubuntu-Studio includes Audacity, a fine basic audio editor without the fine graphic control of levels in other editors, and ease of time dragging program elements.  Ardour, a full featured recording editor is also included.  Many people are afraid of Ardour because it won’t work until set up with jack2.  Fortunately, both  Ubuntu-Studio and DreamStudio have it already set up, so those headaches are gone.  It is still complex and powerful in the same class as Pro-Tools.

DreamStudio also comes with a demo version (upgradable to full version for $80) of Harrison MixBus 3 DAW that has full professional analog simulation with everything that a recording studio would want.  (You need a high quality multi-channel audio card to use it to full effect)  This is a SERIOUS audio editor which does not support compressed audio file formats, so have a big hard disk.  DreamStudio also comes with a host of professional video, animation, 2d and 3d graphics, film post edit, web design and other tools.  The list is amazing, and most are free, and the rest are affordably priced like MixBus 3 and Lightworks NLE award winning video editor.

If your plan is to do a Rivendell – Jack installation for a radio station and Ardour (or Audacity) is suitable for your needs, Ubuntu Studio is the obvious choice.  If you are doing a wide range of  multimedia creations, then DreamStudio is your dream.


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Jack2 Audio Connection Kit

Jack2 is the connector for audio within and between computers.  It connects your audio soundcard to the guts of your computer using a simple to visualize jackfield, where you connect audio paths from one output to any number of inputs.  You can also connect several computers’ audio together over ethernet!  It is available for Linux (Ubuntu Studio), MacOS, and Windows!  It does not know multi-channel audio natively, so you have to hook up the left and the right ‘cables’ independently.

Jack Logo

 

 

My first exposure to Jack was back in Ubuntu 10.04 where I installed it manually in a system that had ALSA (Advanced Linux Sound Architecture) and an early version of Pulseaudio  installed.  It drove me crazy, no audio or audio that had dropouts.  Dozens of settings poorly documented.  AARRRRGH!

No longer! Ubuntu Studio comes with Jack2 already installed so all that grief is mostly behind you.  Many web sources tell you to get rid of Pulseaudio, but the case is not so compelling as it once was, but if low latency or several sound cards are in your plan, dump it.  Check out my article “Use Pulseaudio with Jack Audio Connection Kit?”

You should have your final soundcard(s) installed when you install Ubuntu-Studio so that it can pick up the cards automatically.  Jack comes with a little utility called qjackctl that lets you set all the necessary configuration that lets you correct much of what might not work right away.  No audio can usually be fixed with a command line utility called alsamixer because some sound card drivers set the volume to “0” not “11”.

There are packages from a site called KXStudio that make using Jack2 on Linux beautiful.  If you dive into KXStudio, you will not most of the Jack2 utilities like Patchage, qjackctl, etc.  I will have a script on this site soon that automates installing all these Uber Cool features.

Once you can hook up an audio editor like Audacity to the audio outputs and connect a parametric equalizer to the microphone inputs and the equalizer to Audacity inputs, along a  Jack meterbridge or spectrum analyzer you can see the power of this system. Jack can hook up Lapsda and .vst plugins for a multitude of effects.

NetJack is a way to hook up several computers’ audio  together via ethernetwith one master computer connecting to another, or several others.  This can work over a typical quiet office network, but the NetJack audio should be on its own network with no competing uses of the bandwidth.  If there is too much audio flying around even a 1 GB network can get overloaded.

So, the possibility of shipping audio around between workstations and a server is a real possibility, getting rid of lots of conventional cabling, and removing hundreds or thousands of places where the audio can get degraded.

 


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IP Addresses for LANs

Category : Uncategorized

There are currently two systems for IP addressing – IP version 4 and IP version 6.  Version 6 is important because the world is running out of IP version 4 addresses, as there are only a little more than 4.23 trillion addresses, and we have used most of them up. We are going to concern ourselves in this article with v4 because on a Local Area Network (LAN) there is a neat scheme called Network Address Translation (NAT) that lets us re-use some IPv4  addresses in different local networks, and because IPv4 is much simpler.

IP v4 addresses consist of four, (up to) three digit numbers separated by periods or “tacks” – nnn.nnn.nnn.nnn – where each nnn can be a number between 0 and 255 (that is as much as 8 bits can hold).  192.168.20.3 is an example of a IP v4 address, while 320.168.20.3 would not.  Since a network consists of a number of computers, printers, set top boxes, internet radios, etc. we need to define what IPv4 addresses (numbers) are in your piece of the network called a “subnet”.  This can be done by a construct called a netmask.

An example of a subnet designation would be 192.168.20.0\24 (8 bits x 3 =24 bits) or 192.168.20.0 netmask 255.255.255.0 (another way of saying 24 bits) which says that the last number in the address of a device can be anything from 1 to 254 (0 and 255 are for special purposes)and it is in the subnet.  This particular example is a “Class C” network with 254 addresses available for assignment.  A netmask of 255.255.255.254 would only include two addresses

There are several sets of network addresses that are set aside for LANs as they have been made “non-routable” and cannot be routed over the internet. Any of these can be used for LAN addressing behind a home or office router.

They consist of :

  • 192.168.0.0 – 192.168.255.255  – 255 contiguous Class C networks using 192.268.nnn.000 netmask 255.255.255.0
  • 10.0.0.0 – 10.255.255.255.255 – One Class A network using 10.0.0.0 netmask 255.0.0.0
  • 172.16.0.0 – 172.31.255.255 – 16 contiguous Class B network using 172.16.0.0 netmask 255.240.0.0

A small office LAN will normally be connected to a router that handles the administration of the LAN IP addresses and connects to the internet through a Network Address Translation where communication is done to the internet or your Wide Area Network (WAN) using the IP address(es) of the router, and the LAN computers “Masquerade” as the router address when communicating outside the LAN.

The router usually includes a service called Dynamic Host Configuration Protocol (DHCP), although some networks have this taken care of by a server computer on the network.  DHCP is insufficient for some network components like servers and printers because it is not a sure thing that a device will get the same address back each time it is turned on.  There are some technologies to get over this such as uPnP for printers and other devices.  There are two older techniques which work well but require manual intervention to set up.

Static addressing is the most straightforward.  The computer ethernet interface is setup to (a) specific address(es) within the subnet.  There are several limitations to this.  First, the IP  address must not be also assigned by the DHCP server on the network.  This can be accomplished by configuring the DHCP server so only a portion of the subnet addresses can be issued by the DHCP Server, and the static addresses are within the subnet address space, but not among those that the DHCP server will issue.  The second problem is that the addresses statically configured must be kept track of – manually, usually in a spreadsheet so they can be reached by other computers, and so you don’t assign the address to another statically configured computer.  Another consideration is that many routers keep track of the hostnames of the computers they assign DHCP addresses to.  Usually these office and home routers automatically enter this information into their Domain Name Servers (DNS) which translate www.google.com to an IP Address.  They do this for the computers on the LAN also.  The router has no knowledge of the statically assigned computers, and cannot provide this service for them.

A better solution is to have the DHCP server on the LAN to reserve certain IP addresses for the particular Media Access Connection (MAC) addresses of the ethernet interfaces on  computers and devices on the net that need to always have the same IP Address.  These addresses are printed on the devices, and can be displayed using the ifconfig command on Linux and ipconfig command on Windows. Most modern office and home routers have this function.  You usually have to dig through the DHCP connections list to find the menu item to do this.  The manufacturers think that this is a seriously advanced feature.  On some routers it can be tricky if the computer has already been issued an IP Address by the DHCP server.

If your router has the MAC reserved IP Address function (sometimes the menu calls it Static – Confusing isn’t it?) then it is generally the preferable method.  If your network has no DHCP server, then Static IP Addresses are the only route available.  The Music Networks described throughout this site generally are simple Static assigned networks, while the Office networks have DHCP assignments.


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Network Setup for Rivendell and NetJack

The physical connections between computers running Rivendell and/or NetJack should be done with a bit of thought.  There are some special considerations in any network that carries real time audio or files that must be served on an exact schedule.  This “real time” requirement is different than most computer needs where a document or web page can be served at some time in the future, as long as it is soon.   Audio streams and playout systems need their data NOW.

Rivendell requires Internet access for its rdcatch feature, as well as to access audio files, logs, ssh management, icecast servers. ftp servers and podcast servers, etc.  A Jack server should have access to the internet for the same reasons, plus network time, printers, sending email alerts, etc.  I will call this a connection to the “Office Network” since it includes mostly non-real time traffic.

The safest way (I have thought of) is to have the Rivendell Workstations and Rivendell Server(s) connect to two separate networks.  One network, the “Office Network” carries all the normal traffic, connection to the internet, uploading of logs, printing reports, VoIP, etc..  The other network I call the “Music Network” carries only NetJack traffic, NFS traffic for audio files, and MySQL traffic and some network management traffic.  Rivendell also requires that the Ethernet addresses for these purposes are STATIC, meaning that they are maintained permanently and  setup manually.  The “Office Network” could be automatically assigned using DHCP, or can be STATIC, although there are good reasons that the server interface to the “Office Network” should be STATIC also.

Below is a graphic showing a possible configuration of a Rivendell – NetJack system in  a small radio station, or station cluster.  It is not set up for redundancy to provide high reliability, but later additions will permit this:

Network Layout

Rivendell – NetJack Music and Office Networks

The “Music Network” should use Gigabyte Ethernet interfaces on the computers and switch.  It should use Cat-5e or Cat-6 cables in a unique color to distinguish it from the office network.  If patch panels are used, they should be separate panels from the office network to avoid confusion.  As you can see, only the machines that have real time functions are connected to this net.  There could be a Network Attached Storage device on this network also, but it should not be used for backups, etc.; only for music and playout traffic should be on this network.

In this installation I have arbitrarily assigned the “Music Network” to a class C non-routable set of addresses:

Parameters -192.168.60.0  netmask 255.255.255.0  Gateway 192. 168.60.1 (The server) Broadcast 192.168.60.255.

This means that any device on the “Music Network” assigned an address beginning with 192.168.60. will be a member of this network.  It does not require a router, just a switch since the knowledge of the members of this network and the needed data routes will be known by each of the computers involved.  This network could possibly have 254 devices attached, but you would never want that many.

The “Office Network” is a conventional internet connected network configured to be efficient for its size.  It carries all the regular business and computer traffic of the operation, in addition to providing audio file upload services and possibly streaming sources for Internet Streaming. Conventional network design considerations are appropriate here.  A small station could possibly use the firewall – router provided by the Internet Service Provider (ISP), or another solution with more than one ISP and a load balancing router, a router using DD-Wrt or other open source router software, or Cisco or other “heavy iron” solution.

Not shown here, but for radio stations that need to deliver programming to remote transmitters, there may be a third ethernet interface on the Rivendell Server for a “STL Network” whose exclusive purpose is program delivery, transmitter control and communications to the station transmitters.  The traffic on this network should be separated from the other networks. This network will interconnect using dedicated microwave channels, landline T-1, and/or other methods of data transport  requiring well thought out routing protocols for high reliability.

 


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Use PulseAudio with Jack Audio Connection Kit?

Ubuntu Studio 14.04 uses Pulseaudio -> Alsa -> Jack as the connection interface for audio devices.  Pulseaudio is a very simple interface, and with it most audio cards just “show up” and play with Jack as the pulseaudio-sink and pulseaudio-source devices on the Jack patchbay.

In the olden days (Ubuntu Studio 10.04 and before) Pulseaudio was  buggy and not worth the effort to deal with the bugs.  Pulseaudio is now much more mature, and for a single sound card machine makes it much more likely that you will have Jack working right away.  If you are using Debian or regular Ubuntu, you will need a Pulseaudio plugin to hook it up with Jack.  I have not used the plugin as it is all nicely done in Ubuntu Studio.

Alsa is perfectly capable of connecting sound cards to Jack, with infinitely more flexibility, and (unfortunately) with more complexity.  Remember to turn the volume controls up in alsamixer!

There still remain some reasons to dump Pulseaudio:

  • Pulseaudio works best with a single sound card – if you have an in-computer card and a USB card and want to use both, Pulseaudio is complicated at least and may not let you use the second card. (I have not been successful, but I didn’t try very hard)
  • Pulseaudio devices want to hook up to stuff in the patchbay, and I have not figured how to keep them from automatically doing so.
  • Pulseaudio adds latency to the audio chain.  If you are just recording and playing back stuff and “real time” audio is not important, this might be insignificant.
  • Pulseaudio and Rivendell get in the way of each other.  Rivendell wants to have multiple audio inputs and multiple outputs, and that can be a problem with Pulseaudio if they are on different cards.
  • Pulseaudio devices Pulseaudio-sink and Pulseaudio-source hide the names of the actual sound devices, so they can be confusing when patching.
  • Pulseaudio hides and plays with some sound card settings in Alsa, so special configurations might just get reset to the defaults at next boot.

The reasons to keep Pulseaudio:

  • Alsa can be tricky to get all your audio devices working right unless you are happy to use the command line.
  • Ubuntu Studio comes with Pulseaudio installed and working, and dumping it can cause your installation to stop working until you figure out what Alsa settings for your sound card are undone.
  • There are some tricks to getting Pulseaudio to uninstall or to disable it. (It keeps coming back)
  • Pulseaudio now keeps a simple setup simple (except for those crazy patchbay devices)

Assuming you want to remove Pulseaudio, here is what you do:

From hecticgeek.com:

1. First let’s remove PulseAudio from your Ubuntu OS. I don’t remember since when Ubuntu used to come installed it by default, but for the recent versions such as: 12.04 Precise Pangolin, 11.10 Oneiric Ocelot, 11.04 Natty Narwhal, 10.10 and 10.04 the below command should remove it.

sudo apt-get -y autoremove pulseaudio

2. Now do a reboot since PulseAudio daemon (system service) is also running from the background. So it’s better to let the OS update everything.

3. You need the package alsa-tools, but that is already installed in Ubuntu-Studio, but not in regular Ubuntu.

4.  The script I will be publishing later will do this all automagically.

If you just want to just disable PulseAudio, you can edit the config file

1.   Copy /etc/pulseaudio/client.conf for a backup

sudo cp /etc/pulseaudio/client.conf /etc/pulseaudio/client.conf.orig

2.  Modify /etc/pulse/client.conf  the line   ; autospawn = yes to autospawn=np

sudo sed  s/; autospawn = yes/autospawn = no/ /etc/pulseaudio/client.conf

3.  Reboot or kill the pulseaudio job.


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Where to get Ubuntu Studio

Ubuntu Studio 14.04.x is a distribution of Ubuntu that is available for download as a .iso file, which is a DVD image file.  You need to download the torrent or .iso from the UbuntuStudio.org download page.  A .iso is directly downloaded using Firefox, Chrome or IE.  A torrent will download a lot faster but you have to install and run a torrent client like uTorrent.  You can get uTorrent for Windows here.  There are two versions of Ubuntu Studio, the “i386” 32 bit processor version which will probably work ok, but I don’t recommend it, but if you have a 64 bit machine you REALLY want to load the  “amd64” 64 bit version.  (Yes it works on Intel processors)

Ubuntu Studio 14.04.x (at this time x is 2) is a Long Term Support (LTS) version.  This means that this version will have security and bug fixes coming out for a few years, but no new bells and whistles.  You want to use a LTS version because a high priority in a radio automation system is STABILITY.  The other releases of Ubuntu Studio have new stuff added (and subtracted) with each version coming out every nine months or so.  The way that a system that “used to work” could change, no longer providing the same controls and the people who use it can be confused.  You don’t want your everyday tool to break.

Ubuntu Studio 14.04 is designed as a workstation for audio, video, presentations, graphics, etc.  It has the bare bones of what you need for audio, the special part is that it has properly installed ALSA and Jack and mostly configured them.

Because it has Xfce (a very lightweight Graphical Interface) it also is a very good candidate as a server.  Many people don’t want any graphical interface on a server, but some of the things that are needed for an audio server (Like Jack and KXStudio) run in graphical mode only, so Ubuntu Server is not a good candidate because you would have to install a GUI that needs a lot of setup, and Ubuntu Desktop has just too many pretty gizmos clogging things up to hammer out audio production and automation.

As a server, you will have some work to do – putting in a webserver, samba file sharing, routing, etc., but that has to be set up for your configuration no matter what.  The installation part is simple.

After you download or torrent the file to your computer, it needs to burned to a bootable DVD or a 4 Gig or larger Flash Drive.  For DVDs, Windows 7 has this ability built in to Explorer, and for Ubuntu the instructions are here.  For flash drives, you can’t just copy the file over, it needs to be written as a bootable image.  There are lots of free programs out there to burn iso files to flash drives, but Google searching will bring up many listings for the utility that can only write Windows 7 or Windows 8 iso files.  Avoid that utility.

Some motherboards will not boot from a flash drive, and you need to play with the bios to get a DVD or Flash Drive to boot when there is an old operating system on the hard drive.  You will be making the machine a  Ubuntu Studio ONLY machine.  No dual boots or Virtual machines for audio!  You want to lock this machine into one mode only so it will be reliable and simple. Yes you can play with a virtual machine, but it will never be a real “workstation”, as would be the case with regular Ubuntu.

When the DVD or Flash Drive boots, make sure you check the disk before installing.  That is one of the selections on the first menu.  It would be really a shame to spend an hour or so setting up a Ubuntu Studio system only to find that half the stuff doesn’t work.

You will need to babysit the installation for a few minutes.  The machine needs to be connected to the Internet and a DHCP server.  I don’t install the photo finishing, graphics and presentations application installation, and you could drop the video apps if you are sure you will not be needing them.  If you are not going to use my script, let the system update all the files on installation.  You can walk away for a cup of coffee after the initial entries quiet down, then check back later when it is installing MySql for passwords and stuff.  It will stop and wait for the password entry.  When it is done –

Take out the DVD or Flashdrive and reboot – voila!  A fresh Ubuntu Studio installation.

 


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Don’t Edit /etc/security/limits.conf

There are a number of sites that say to edit /etc/security/limits.conf.

Ubuntu Studio 14.04.2 automatically makes the entries for Jack in

/etc/security/limits.d/audio.conf

on installation.

The debian.tryphon.eu  Rivendell package automatically sets them up in

/etc/security/limits.d/rivendell.conf

These files get read in by an include statement in /etc/security/limits.conf so all is good, don’t edit limits.conf.

The general philosophy with jack is to protect application’s priority by protecting the transport.  If you have a busy audio processor or something else that MUST run in realtime you might want to add a file for it in  /etc/security/limits.d/  reserving its necessary memory and a negative nice value closer to zero than that of Jack and Rivendell.   This is unnecessary unless you have overruns or gaps or frequency or time shifts that are otherwise unexplained.

Another source of problems can come from hard drive partitions that are filled up.  Beware of backup programs, log files, etc. in a partition that is pretty full.  Ubuntu studio hangs up waiting for disk writes to complete.


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Hardware for Audio – Server and Workstation

The Workstation

A Rivendell workstation with Jack2 and Netjack to work with a server needs a reliable motherboard with an X64 processor  with two to four cores, Several Gigs (3?) of Memory, and if to be used with a server for audio storage and database, probably 120 Gigs of SSD.     If the machine will be in a playout or editing environment, an SSD is important for fast boot  and fast loading of applications. The $50 a little SSD costs is well worth it.  An additional hard drive is needed to keep keep work files in the /home folder.  If you have a good server, you don’t need a big hard drive unless you want to duplicate the library and database on the workstation (this is tricky because they need to be kept sync’ed)

If you work with a server, you need a good quality Gigabit network card which you will set up for STATIC ADDRESSING.

You need a good sound card fully rated for ALSA compatibility.  I have used M-Audio hardware with good results, particularly the Delta 1010 cards and the all of the 17xx cards work well too.  Ubuntu studio 14.04 has also learned to play nice with M-Audio Fast Track 8R USB rack mounted box. (earlier versions did not)  Rivendell loves the Audio Sciences cards, but they are pricey.

If the workstation is in the studio, you also want high volume LOW NOISE fans. Bigger cabinets seem to have quieter fans because they use larger 120 mm fans that move more air with slower blades. You should also use a good quality power supply and UPS.  The UPS should be connected to the computer USB for graceful shutdown when the power goes out, and stays out.

The current version of Rivendell playout has a fixed window size so don’t go crazy on resolution or the control window will be too small.  (I have heard that this is likely to change in the next major revision).   Your video card does not need to be anything special, motherboard cards work fine.  rdAirplay will work with a touchscreen, and there are many that work with Ubuntu-Studio, but not all.  Your touchscreen mileage may vary.  You are looking for high reliability, not blazing performance. Do not overclock.

Rivendell works with audio switchers such as the Broadcast Tools SS 8.2, and with digital IO cards that talk by RS-232 serial ports.  It would be nice if the motherboard had an RS-232 port, but a high quality USB-RS-232 converter will work.  There are cheap converters that won’t work because they need a special driver that might not be available in Linux.  The machines that will be running RdCatch and RdAirplay will need this if you need these outputs to switch satellite receivers and such.  (Audio switchers may be unnecessary if you have enough inputs and outputs on your soundcards when running Jack2.)

The Server

A server for Rivendell should have similar computing  performance to the workstation, and should have a reasonable amount of memory on a multi-processor X64 chip, with four or more gigs of memory.  Hard drives should start with a 128 Gig SSD for the operating system, and about 2 TB or more of high quality hard drives for audio and database.

You should have two or three Gigabyte Ethernet ports on this machine.

It theoretically could be a “headless” machine, but some of the audio applications just really need GUI interfaces.  Sharing a monitor, mouse and keyboard with a KVM switch with another machine (such as a standby server) would be useful.   Be careful that the KVM switch and the motherboard have the same mouse and keyboard connectors.  USB to DIN adapters generally don’t work on KVM switches. No fancy video card is needed.

If this will be the “master control for audio” it will need a good ALSA compatible sound card with as many output channels as you will have outputs.  The server should have at least a 2 TB  USB removable drive or a Network Attached Storage device for backups.  You may have trouble finding servers that are quiet enough for the average station.  If you will be running the servers in a server closet, I recommend recently pulled 1U to 4u servers with dual power supplies. They will, however, be much too noisy for an office or studio environment.  You probably can’t afford them new, but used are inexpensive, just make sure you get multiprocessor X64 machines with enough memory

Your “music” ethernet network should be built with good Cat6 cables – any that go through the ceilings or floors should be ‘plenum’ rated.  Use high quality gigabit switches.  You probably can do without managed switches unless you have a lot of workstations, and then we have to tune things that I haven’t had to do yet.

It is possible to set up a server standby system for Rivendell, where you have two identical servers for Rivendell and the audio store or the database are kept up to date on both.  This way a failure will not put you off the air until a new server can be configured.  Similarly, you should keep your workstations as close to identical as possible  so you can switch over quickly in the case of an equipment failure.

If you are doing hot standby  servers, it would make sense to have two independent UPS systems – one for each server, and a ups for each workstation.  The idea is “no single point of failure”!  This is where the use of a real router (not bestbuy specials, but microtik or cisco) become important.

When you set up Ubuntu studio on these machines make sure you choose to add .mp3 codec and use LVM.  The account you use to setup will be the main “SUDOER” account.  Use a real password and require it to be entered.  It might make sense to encrypt the main account’s /home folder.

The server might be called on to do more than switch audio, serve the databases, and stream.  You may want to run the station’s phone system using freeswitch, or at least the phone interfaces to the studio.  It may make sense to put these into separate “boxes” using Oricle’s Virtualbox or the more sophisticated OpenStack. If you are thinking about using openstack, you will need at least one processor per “node” so a six or eight processor computer for the server makes sense, along with more memory, as each node has its “own” memory.


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