DIYVS Low-Cost Virtual Studio Device

Assemble your own JackTrip Virtual Studio and save money

Note: The JackTrip Virtual Studio software has been updated so that this project will work with most USB audio interfaces and audio adapters. There is no longer any need to modify or update this software yourself.

Introduction

Until recently, solutions for playing music together remotely have primarily been software-based. Initially, groups of telemusicians tried to use video conferencing applications such as Zoom, but that didn’t work out very well because of excessive audio delays.

Purpose-built applications, such as Jamulus, JamKazam, and JackTrip have become popular, running on general-purpose computers (Macintosh, Windows, or Linux). However, these computers still create audio delay problems because they are constantly interrupting themselves to do other things — downloading email, performing backups, beeping when notifications arrive, checking social media, and updating software — which disrupts the music. Also, such programs are difficult to install and set up for good results. Running these applications on a dedicated computer (such as a Raspberry Pi) solves many of these problems, but it requires technical skills for audio, and for computer hardware and software.

The JackTrip Foundation reduces the need for deep technical skills by creating and selling a dedicated computer appliance, called the JackTrip Virtual Studio device, combining a fast but inexpensive Raspberry Pi computer with a low latency audio interface, with all the software pre-installed and automatically updated. This device has a friendly user interface, and is configured to connect to servers managed by the JackTrip Foundation (and others).

Because of its low latency and ease of use, the JackTrip Virtual Studio is fast becoming the method of choice for telemusicians — it is already used by groups containing hundreds of players and singers. The current stock JackTrip Virtual Studio device (the “device”) is an amazing piece of hardware. Its benefits include:

  • Extremely low latency, less than 1mS (millisecond) delay. Tested against audio interfaces costing much more, and it has demonstrated superior latency and jitter specs, both of which can be extremely important when musicians want to create professional-quality music over the internet.

The stock device costs $150 on Amazon, which is surprisingly low compared to most high quality audio equipment. For example, commercial audio interfaces can cost hundreds of dollars, and yet this affordable device contains both an audio interface and a powerful computer with a gigabit internet connection.

At the same time, the key software that runs on the Virtual Studio device, JackTrip, is open source, and it has always been possible for advanced technical hobbyists to build their own device. In fact, the JackTrip documentation provides information about how to do just that. But as the Virtual Studio has started to become popular, we have noticed a substantial gap between professional musicians (who want the highest quality), and the technological hobbyists who have the skills to build the hardware and software they want at lower cost. This gap includes:

  • Amateur musicians, who don’t necessarily need the absolute highest quality of sound. They just want to be able to sing and play together, or jam with other musicians for fun, but don’t want to spend hundreds of dollars on the necessary equipment.

With the pandemic, this gap has become huge. There is strong demand for a lower cost, but still good solution that is accessible to people who are not necessarily technically sophisticated.

DIYVS

The solution is to take advantage of audio components that have mostly been created for other markets (like computer gaming) that are relatively inexpensive but are of sufficient quality. Alternatively, utilize audio interfaces, which many musicians already have and like. These allow different audio equipment to be combined with the inexpensive but powerful computer board already used in the high-end device, and meet the needs of the users in the gap.

Users will do final assembly themselves, so it will qualify as a hobbyist device and thus avoid FCC (and other countries’) compliance testing, which would be prohibitively expensive because of the myriad permutations of audio equipment that would need to be tested. The individual components are FCC compliant, so there should not be any interference problems.

DIYVS can also be less expensive because it does not include commercial-level support. As with many new products, support is being done by the existing, fast-growing community of users who have already built their own Virtual Studio, and who are already well-connected with other musicians, both professional and amateur. (I know this because I am one of the many unpaid volunteers who are helping to support the Virtual Studio).

This project is named DIYVS (for “Do It Yourself Virtual Studio” (pronounced DYE-vis). This article tells you how to build one yourself. The parts are all off-the-shelf and can be purchased online. Assembling the parts takes an hour or less, even for people with only basic computer skills.

Parts List

These parts are suggested examples. You can purchase from other vendors (for example, Sweetwater and Monoprice), or even other brands. Prices quoted are in US dollars, not including any sales taxes or shipping costs. It should be easy to find everything you need almost anywhere in the world.

Raspberry Pi 4 Model B, with 2GB of RAM

You can buy this for $35, from one of the vendors listed on raspberrypi.org. Amazon has them too, but at higher prices.

Metal Case

A metal case is recommended for keeping your audio free of hum and noise. Amazon carries an aluminum case made by GeeekPi for $15.99 that also includes a power supply with an on/off switch, some stick-on heatsinks, a fan (which you don’t need to use), a small screwdriver for the screws, and instructions on how to assemble it:

Amazon also has a similar package from Vilros that includes the Raspberry Pi, plus a monitor cable, all for $66.99. Most of the vendors recommended on raspberrypi.org also sell Raspberry Pi starter packages.

Power Supply

If not included with your case, you can buy a power supply by itself for around $8 (not including an on/off switch). You should not skimp by using a power supply meant for a phone (even if you have a spare one lying around).

Alternatively, Canakit sells an approved power supply with slightly higher power and a convenient on/off switch for $10.99 on Amazon.

Micro SD card

Note that the JackTrip Foundation is about to start selling Micro SD cards already containing the needed software. They will look something like the following image, with the JackTrip logo. I will update this article when that happens. Until then, you will need to get a blank card and add the software to it yourself. Or you might want to do it yourself if you have a spare Micro SD card. This article explains how to do that.

You need at least 2GB, but the smallest ones for sale nowadays seem to be 8GB, and 16GB cards are now generally less expensive than 8GB ones. You can also use 32GB cards, but if you want to use anything 64GB or larger you will have to reformat it, so stick with something smaller if you can (probably 16GB or 32GB).

Your card should be at least Class 10 (a measure of the speed of the card), as shown by the 10 placed inside the letter C, shown on the SanDisk card in the figure below. Cards like the Samsung, below, which instead have a number placed inside a letter U, are at least Class 10 and will be slightly faster to boot up. Here’s a comparison of various Micro SD cards, including their speed on a Raspberry Pi 4B (for this project, you will be most concerned about boot times).

You should buy a brand of card that is known to be good, as there have been lots of substandard cards sold. SanDisk, Samsung, Micro Center, Kingston, Patriot, Pioneer, and Transcend are good brands. The card shown above by SanDisk can be bought from Amazon for $6.19, and it even includes an adapter card, which you might need. The Samsung card has twice the capacity, is faster, and lasts longer, and Amazon sells it for $8.99 (also including an adapter).

USB Audio Adapter or Audio Interface

A big advantage of building your own Virtual Studio device is that you can use other audio interfaces and adapters, possibly including ones you already have. Here is a list of audio adapter and audio interfaces that have been tested by the JackTrip Foundation to work with the Virtual Studio software. For this project we are focusing on those with a USB connector. Even when limited to audio interfaces that use USB connectors, there are literally hundreds of them out there. If you find one that works, please send a message to me about it.

These audio devices are divided into several kinds: Audio Adapters (sometimes called external sound cards), Audio Interfaces (more expensive), and USB mixers (also expensive).

Audio Adapters

Audio adapters are designed as external sound cards for computers. These are meant for gaming and listening to music, and are quite popular, so they are relatively inexpensive (around $5 to $30). I’ve compiled data on latency and noise floor for these adapters.

On most of these, the microphone input is strictly mono, but using a (stereo) TRS jack. Unless otherwise noted, the input and output volumes are adjusted using the JackTrip web app, and the adapter supplies bias power, so it can be used with condenser microphones.

A. Sabrent Aluminum USB External Stereo Sound Adapter

Pros: low cost — $7.99 on Amazon, metal case (assuming you buy the aluminum version, which is the same price as the plastic case), reasonable latency, and includes a USB extension cable. I have one and it works just fine. Cons: some people complain that it sounds scratchy. I think this might be because it has high gain on the microphone, which can cause it to overload and clip the JackTrip server. Try turning down the “Input Volume” on the web app to around 50 to 60 and see if that solves the problem.

B. UGREEN USB Audio Adapter External Stereo Sound Card

$13.99 on Amazon. Lower noise, can set Input Volume on the web app to around 80.

C. Syba external USB Stereo Sound Adapter

$8.99 on Amazon. Works OK.

D. DuKabel USB Audio Adapter for Gaming Headset

$9.99 on Amazon, metal case, cloth braided cables. Has high gain and poor noise floor, so try setting the Input Volume on the web app to around 60. If you turn it up higher, you will hear noise (hiss).

E. StarTech.com USB Sound Card w/SPDIF Digital Audio & Stereo Mic

$30 on Amazon. Has multiple sample rates (44.1/48/96 KHz), SPDIF digital output, a simple equalizer and the mic input is true stereo. It also has a physical output volume control (and the output volume can also be adjusted from the JackTrip web app).

Audio Interfaces

High quality audio interfaces typically include XLR microphone connectors, phantom power (so you can use condenser mics), clipping indicators, and level controls for both the microphone inputs and headphone output. Most audio interfaces include multiple inputs; for example, if you want an input for a musical instrument pickup in addition to a microphone input for your voice. These run from $50 on up to more than a thousand dollars. If you use one of these, you will set your volume levels on the interface, not using the JackTrip web app.

F. Focusrite Scarlett 2i2

A very popular audio interface. It is currently selling for $159.99 on Amazon (the price has gone up due to heavy demand during the pandemic).

G. Presonus AudioBox USB 96

$99.95 on Amazon.

H. Behringer UM2

Around $47 on Amazon. Handles one mic and one instrument pickup.

USB Mixers

Mixers that connect to a computer using USB. I haven’t tested any of these yet, but if you have, let me know.

Estimated Cost

You can build this Virtual Studio device yourself with the Sabrent audio adapter for around $65. For comparison, the existing JackTrip Virtual Studio device sold on Amazon costs $159.98, (including the power supply). That’s significantly less than half the cost. And it can be even less if you already have some parts (like an audio interface or adapter). And you don’t need to buy the adapter cable to convert the two RCA jacks to a stereo TRS connector for headphones (saving you an additional $5), because the Sabrent audio adapter has a TRS headphone jack.

Another advantage of DIYVS is that you can customize it to your needs. For example, if you just want to practice together, or jam with friends, the low-cost Sabrent audio adapter will work just fine. Or later, if you need higher quality, you can upgrade to a powerful audio interface.

Other Accessories

Like the existing JackTrip Virtual Studio device, you will need some additional things before you can play music together remotely. The recommended accessories for the existing Virtual Studio device are listed in the JackTrip documentation. This article mainly explains a few differences, and suggestions for low-cost but good quality alternative accessories.

I’ve also written another article that is more detailed about possible accessories. You should read it for more information.

Ethernet Cable

You will need an Ethernet cable. It needs to be long enough to reach your Internet modem and router. Do not use WiFi.

Headphones

Do not use wireless (e.g., Bluetooth) headphones. As mentioned, you will not need the adapter cable.

If you use the Sabrent audio adapter, then headphones with a 3.5mm TRS plug will plug in directly. If you use an audio interface, most of them use a ¼ inch (6.35mm) TRS jack, so you will need an inexpensive adapter.

Alternatively, you can use wired earbuds, not wireless, and preferably ones that do not include a built-in microphone.

Microphone

You can use (less expensive but good sounding) microphones meant for use with video cameras. These mics have the advantage that they are generally designed to work with more distant sounds, so they are more sensitive. They also generally use the same 3.5mm TRS plug used by the Sabrent, and many other audio adapters, so they can just be plugged in, with no adapter needed.

For example, I just bought a MouKey video microphone from Amazon for $17.42 (it is on sale for 30% off), which includes a foam cover, so it can be used for singing. It also includes a deadcat windscreen (to avoid wind noise when used outdoors), and a shock mount that can fit onto the hot shoe of a camera or onto a standard tripod. I use an inexpensive desktop camera tripod to hold it. It sounds amazingly good for its size and price.

Note that this mic will not work with the existing Virtual Studio device, because it requires bias power. But it will work fine with most Audio Adapters discussed in this article.

I also have a Sony stereo microphone, which plugs directly into the Sabrent (in mono), and sounds very good. Using the StarTech.com USB Sound Card, it works in true stereo! However, I don’t think Sony makes this mic anymore (I’ve had it for many years). But there are other stereo video camera microphones available if you want.

One downside of microphones meant for cameras is that they tend to have very short cables. But you can use longer, inexpensive 3.5mm TRS cables instead.

Of course, you can also use many other styles and brands of microphones. Depending on their connector, you might need an adapter cable. And if you are using an audio interface (like the Focusrite or Presonus), those have a balanced XLR jack for the microphone, so you might want to use a microphone with an XLR connector.

Building your Virtual Studio device

Building your own Virtual Studio device is actually surprisingly easy, even if you don’t have many technical skills. The only somewhat difficult thing is downloading the JackTrip Virtual Studio software and installing it on the Micro SD card and then inserting the card into the Raspberry Pi. If you need help, you can find a technical person who will do it for you (typically in exchange for some flat food, such as pizza).

Note that soon it will be possible to purchase a Micro SD card with the Virtual Studio software already installed. At that point, assembling a DIYVS will be even simpler.

Tools you will need

If you purchase the Micro SD card with the Virtual Studio software already installed, you don’t need the last two tools. And you may not need a screwdriver if you buy the case mentioned earlier, because it includes the needed screwdriver).

  • If your case has screws (some don’t) and doesn’t come with a screwdriver, you may need a relatively small one.

Steps

If you purchase the Micro SD card with the Virtual Studio software already installed, you don’t need to perform the first two steps.

  • Install Balena Etcher onto your computer.

Setting Audio Levels

An important thing in getting various USB audio devices to work well is to set your audio levels correctly. This is normally done using the JackTrip web app, accessed at app.jacktrip.org.

The Input Volume controls the mic input of your audio adapter, and thus the volume of your microphone. Different microphones will have different output levels. For example, the MouKey microphone suggested earlier has a fairly high output, and if the Input Volume control is set too high it can overload the signal, causing scratching or popping sounds. If this happens, using the web app, turn down the Input Volume and/or turn off the Boost switch.

The Output Volume controls the headphone output of your audio adapter, and thus the volume you hear in your headphones. If you need more volume, using the web app, turn up the Output Volume and/or turn on the Boost switch.

Depending on your audio adapter and your headphones, you may still need more volume, in which case you have a couple of options. You can use a different audio adapter, including switching to an audio interface which has its own input and output volume controls (in which case you will not use the web app to set these levels).

Alternatively, you can buy a headphone amplifier (around $20 or so). Most headphone amplifiers can drive more than one set of headphones, in case you want to have more than one person playing or listening to music over the internet. The Behringer HA400 can drive up to four headphones with individual volume controls, and sells for $24 on Amazon. It uses 6.35mm (¼ inch) TRS connectors instead of 3.5mm, so you will probably need some inexpensive adapters.

Setting proper levels is especially important when you have people playing together who are using different USB audio devices, different microphones, or are standing at different distances from their microphones. Each player will need to set their own Input volume so everyone can be heard equally.

Further Reading

JackTrip Virtual Studio overview.

JackTrip documentation for Virtual Studio.

JackTrip website.

Virtual Studio online app.

Information about latency, lag, and jitter.

JackTrip users email list.

If you are confused about connector types (like TRS, XLR, RCA, etc.) Sweetwater has a nice guide to the common ones. Also see this article about balanced versus unbalanced cables.

Musician, computer scientist, artist.

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