Jamulus
Hardware you will need:
1. Computer. A Windows or Mac computer (not a smartphone). The computer doesn't really need to be seriously state-of-the-art or particularly new.
2. Music Equipment. To get the sound into the computer, you cannot really use the mic that may be built into the computer - the quality will be too low. A singer or someone using an open-air instrument (as opposed to, say, a keyboard or electric guitar/bass), should use a condenser USB mic (like the Blue Yeti or Blue Yeti X or AT 2020USB+). Folks who play an electric instrument like a keyboard or electric guitar/bass should add a USB mixer to their setup, like the Behringer Q302USB or Behringer Q502USB, so they can connect both their instrument and a microphone (for talking / singing) to the computer. In my case, I use a Behringer Q502USB (John Payne uses the Q302USB). I have an AT2020+ standard (not USB) condenser mic that I plug into one channel (that has a phantom power supply) on the mixer via an XLR cable. I connect my keyboard to another mixer channel via a standard 1/4" patch cord. I then connect my mixer to the computer via the USB cable. You need to make sure the mixer can supply phantom power if you're going to use a condenser mic in this sort of setup; if you're connecting a USB mic directly to the computer you don't need to worry about phantom power - the computer will supply it through the USB cable.
3. Headphones. To listen to the sound coming from Jamulus, you need a set of *wired* (Bluetooth adds unacceptable delays) over-the-ear headphones (I like the Cowin E7, which you can use wired or wirelessly and has a really good battery life). I plug my headphones right into the computer's headphone jack. One key point - to avoid feedback you don't want any of the Jamulus sound spilling into the open air (say, using your computer's speakers). Another key point is that you don't want to monitor your sound - you want to monitor everyone's sound. Finally - the cables that typically come with headphones tend to be a bit short - but most good headphones, including the Cowin E7, let you replace the cable, and it is pretty inexpensive to buy a longer one (typically a decent 10' male-to-male 3.5mm cable would cost less than $10).
4. Ethernet Connection. Finally, to share your and your bandmates' sound, you will want to use an Ethernet cable to connect your computer to your router / Internet access point. Avoid WiFi if at all possible - even if you have a fast WiFi Internet connection overall, there will be musically significant delays if you try to use WiFi. If the computer has no Ethernet port, there are plenty of cheap gigabit Ethernet (RJ45) to USB dongles that can be used. Ethernet cables can be really long and still be super-fast. In fact, I'm typing this email on a computer connected to my router using a 75' cable.
Software you will need:
1. You can download Jamulus, itself, at https://sourceforge.net/projects/llcon/. The download is free. Install it after downloading it.
2. If you're using a PC (but not a Mac), you should also download and install a separate piece of free software that helps Jamulus communicate with minimal delay called ASIO4ALL (currently version 2.14), at http://www.asio4all.org/. If you use a Mac, though, you don’t need ASIO4ALL.
Using Jamulus
Once you have all the hardware set up and all the software installed, you can start Jamulus.
Sound Setup. The first thing you need to do once you start it up is to make sure Jamulus is set up to use the right sound inputs and outputs. First, open Jamulus's "Settings" window by clicking on the "Settings" button in the main Jamulus window (on the left side). If you are using a Mac, select the device you want using the Mac's System Preferences / Sound. If you are using a PC (not a Mac), make sure the "Device" listed in the upper left corner of the Settings window is "ASIO4All v2". Then, if you have multiple sound input and output devices, you can control which one is active by clicking on the "ASIO Setup" button on the lower left side of the settings menu. This is the trickiest part. A device is selected when the little "power" icon to the left of its name is selected and the light blue "pointer" triangle is lit. Make sure that just one sound input (your USB mic or mixer) and one sound output (your headphones) are selected.
Name and Instrument Setup. Set up your name (and instrument, if you want) in Jamulus so folks know who you are. In the PC version, you can do that by clicking "View" (in the menu bar at the top) and then "My Profile".
Testing Your Setup. You can check your setup using my remote server (which is sort of slow, but good for testing), 3.213.11.133, or using the server at John Payne Music Center, 73.114.128.124. Click "Connect" in the main Jamulus window, then fill in that number in the "Server Name/Address" field at the bottom of the "Connection Setup" window that comes up, and then click "Connect" in that Connection Setup window. When you're done, click "Disconnect" in the main Jamulus window.
Adjusting Your Sound Mix. Once you and your bandmates are connected, you can adjust your personal sound mix by moving the volume sliders up and down over everyone's names where they appear in the main Jamulus window. Note that adjusting the sliders only affects your mix - it doesn't change what your bandmates here. Next to everyone's volume slider are a set of level indicator lights. You should all strive to have your mic / mixer settings such that each of you has an appropriate sound level, with sounds maxing out somewhere around the top of the green / bottom of the white, and that you avoid triggering the red sound level lights.
Jamulus Performance / Delays. You can monitor lag time / delay in the "Settings" window, on the lower right hand side. Any "Overall Delay" of 60-65 ms or lower should be pretty manageable for playing together.