Looking for a wireless system for your musical instrument, but don’t know how to separate the wheat from the chaff? Keep reading for an overview of the most important specs to pay attention to when choosing the best wireless audio solution for your needs.
Already know the basics and just want to see some recommendations? See our list of the best wireless guitar and bass systems.
What to look for in a wireless audio transmitter/receiver system
1. Analog or digital?
Wireless instrument systems come in two basic types: analog and digital. As in anything, analog is older technology and therefore more limited in some aspects, but also more battle-tested than digital. As a result, budget and mid-priced analog systems usually offer poorer quality than similarly priced digital systems, while in higher price brackets, the two can be more equally matched.
1.1 Companding and digital conversion
In order to transmit audio over a radio wave, analog wireless systems need to compress the input signal at the transmitter and then expand it again at the receiver (known as “companding”). In this process, some of the original audio signal is lost, resulting in the wireless system eating away at the natural tone of your instrument compared to wired setups and producing sound artifacts known as “breathing” or “pumping”.
Digital wireless systems do away with companding by converting the analog audio to digital data, which is then captured by the receiver and reconverted to an analog signal, thus avoiding radio-frequency interference and preserving the complete dynamic range of the original signal. Simply put, digital wireless systems generally offer better audio quality.
1.2 Frequency bands
Analog wireless systems operate in the VHF (Very High Frequency – 30 to 300 MHz) and UHF (Ultra-high frequency – 300 MHz to 3 GHz) frequency bands used by TV and radio channels. UHF, with its wider choice of frequencies and less TV and radio interference, is more common in professional quality analog wireless systems. Both bands, however, are becoming more and more congested every day as well as requiring a license to use in many countries.
Many producers of digital wireless systems are trying to get past these limitations by turning to the 900 MHz (not available outside the US and Canada) and especially 2.4 GHz ISM (industrial, scientific and medical) radio bands not available to analog systems. The 2.4 GHz band is most common as it is license-free worldwide and generally less prone to interference, although nearby Wi-Fi and Bluetooth signals, which utilize the same frequencies, can sometimes cause problems – increasingly so with the advent of smartphones.
Meanwhile the 900 MHz band is free from the latter as well as most TV and radio signals, though also used by amateur radio, walkie-talkies, cordless phones, and other short-range consumer wireless devices, as well as being relatively narrow. Wireless systems operating in either of these bands also have a smaller choice of available channels compared to UHF systems – normally around 4 to 6 – so if you need to use a large number of them simultaneously (e.g. for a full setup in a larger band), you might need to turn to UHF-based devices.
At the same time, the future of UHF wireless microphones is currently deeply uncertain as the FCC is looking to auction off a good chunk of frequencies in the 600 MHz band. The extent and time of this is still unknown, though when it does happen, TV broadcasters and wireless microphone operators and manufacturers working in this spectrum will be given 39 months to free those frequencies. So not only will many UHF wireless systems be ousted from their homes, the rest of the spectrum is bound to get even more cramped from the switchover. This means that if you’re looking for the most future-proof solution, the 900 MHz and 2.4 GHz bands are still your best bet.
The downside of digital wireless systems is that the digital conversion process introduces latency, which is not there in analog systems. For live music performances, you might start noticing this at around 8–10 ms of latency. While lower is obviously better and you should keep an eye on latency specifications when choosing a digital wireless instrument system, however, most of today’s digital wireless systems have managed to bring latency down to entirely negligible levels, where, for most applications, it should never be an issue.
To top it all off, digital wireless systems can also use encrypted data transmission, protecting the audio signal from hijackers and eavesdroppers.
Analog or digital: Conclusion
Based on both user reports and the above, then, we must conclude that when it comes wireless instrument systems, there is no real reason to prefer analog to digital outside of the need for more available channels. Even then, there are digital UHF-based systems out there with the same capabilities as analog ones (or even better). For the most part, modern digital wireless systems have simply proven to be the more reliable and cost-effective option, which is why our list of the best wireless guitar/bass systems only features digital models. This is not to say that there aren’t good analog systems out there, but we’ll take any edge we can get.
2. Frequency agility and channel auto-select
A wireless system with frequency agility, as opposed to fixed frequency, can switch between multiple channels to avoid interference. It will cost you more, but unless you’re using a single wireless system in a fixed location – and, as conditions can change, sometimes even then –, frequency agility should be considered a must-have. Pricier models can also select the best suitable channel automatically and instantly switch between frequencies as necessary, freeing you from the hassle of manual tweaking and adjusting.
3. Diversity features
In signal transmission, diversity refers to the use of several different communication channels to protect the system from unwanted interference and/or signal dropouts and dead spots. This can be achieved by using multiple sending/receiving antennae (reception diversity), with the system monitoring signal strength at each one and picking the best signal; by transmitting the signal at different time intervals (time diversity); sending the same signal simultaneously over multiple frequencies/channels (frequency diversity), etc. While no method can completely remove the threat of wireless audio dropouts, they do reduce the likelihood of their occurrence by severalfold and are thus a staple in higher end systems.
4. Operating range
As the operating range of wireless instrument systems depends on a variety of factors, including objects/walls in the signal’s path, other signals in the vicinity, etc., most manufacturers only give a typical operating range for their products. This generally falls between 50 feet (15 meters) and 300 feet (90 meters), depending on the price range, but even so, in practice, your mileage may vary. Therefore, if you want to be sure you’ll be getting the range you need, choose a system with stated operating range to spare.
5. Frequency response and dynamic range
Frequency response and dynamic range are two basic measurements of sound quality. Frequency response refers to the range of frequencies a system can reproduce. As human hearing covers the range from 20 Hz to 20 kHz, a system that can reproduce those frequencies, should, in theory, sound “natural”, while more limited ranges would mean that some frequencies are getting cut. Wider frequency ranges, especially in the lower end, won’t hurt – in fact, sounds outside our hearing have been shown to affect sound perception –, but will cost more, while shorter ranges will be noticeable to an extent. This is especially important to keep in mind when choosing a wireless system for a bass guitar (or other lower range instrument), as a more limited lower end will manifest in a thinner tone.
To get the full picture, however, frequency response should be given with volume/amplitude variation at said frequency range – generally acceptable at +/- 3 dB. This means that within said frequency range, sound levels do not vary by more than 3 dB in either direction, providing a so-called “flat” frequency response, meaning the system does not color your tone.
Dynamic range, in turn, refers to the ratio between the noise floor and the loudest undistorted sound and is thus a measure of sound quality. The higher the dynamic range, the less noise there is in a system at higher volumes. Generally, 100 dB is considered the minimum for high-quality audio. When dynamic range is measured in relation to the human ear (which has an uneven response to different frequencies), it is marked as A-weighted – an indication of better accuracy.
6. Battery type and life
Most wireless transmitters work best with single-use alkaline or lithium batteries and many manufacturers advise against using rechargeable batteries with their products. Sadly, this is not a battery manufacturing conspiracy. Single-use batteries simply provide a more stable power output than, for example, nickel-cadmium rechargeables, which drain faster (in a mere 2–3 hours) and will not display their charge levels accurately, so you might not get much warning before your batteries give out on you. For higher end products, though, many manufacturers have begun to supply proprietary rechargeable batteries.
You will also want to pay attention to battery life, which can range anywhere between 2 or 3 hours to around 12, more typically 6 to 8. Though this should be enough for most applications, it is a good idea to get a backup set just in case.
7. Cable tone simulation
In wired instrument systems, one of the many factors that can affect sound is the type and length of cables. Longer cables mean higher capacitance, which leads to reduced higher frequencies and vice versa. Some musicians choose their cables specifically for the tone they impart on their sound. Recently, some wireless instrument system manufacturers, such as Line 6, have begun implementing cable tone simulation features in their wireless systems, allowing you to choose from a variety of cable tone settings. If cable tone is something you care about and don’t want to lose when transitioning to wireless, be sure to keep an eye out for these solutions.