Category Archives: Server

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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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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 -  netmask  Gateway 192. 168.60.1 (The server) Broadcast

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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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 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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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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