Note: Last month, we discussed the basics of Bluetooth. This month, we look at how Bluetooth technology is being used in some pro audio applications.
The most common consumer application for Bluetooth is probably the use of “earpods” for streaming audio from a smart device (i.e., your phone). Just about every smart phone can stream music and voice for phone calls, making wired headphones unnecessary. At this point in time, however, Bluetooth is probably not the best way to stream audio for critical pro audio applications. First, BT can’t stream high-res (or even normal-resolution) audio. Second, a BT connection is not particularly secure, and third, BT connections can be interrupted or dropped fairly easily (sometimes due to static pops). For those reasons, it’s probably not a good idea to stream backing tracks for your band via BT.
The convenience of Bluetooth, however, is undeniable. It’s definitely the easiest way to stream background or break music, especially since headphone jacks are becoming increasingly scarce on smart phones and laptop computers, and adapters are clumsy at best. How do you incorporate BT streaming into your audio system?
BT Speakers
Bluetooth-enabled speakers are popping up like weeds in both the pro and consumer audio markets. A portable wireless speaker that can play music from your phone while you’re lounging at the beach or on the patio is an attractive proposition. Pro users will need more than just the ability to stream music, and there are plenty of sound reinforcement loudspeakers with a built-in Bluetooth audio input. One such speaker is Yorkville Sound’s 200-watt EXM-Mobile-8, a portable speaker that can be powered via AC or battery (up to 12 hours). It has a three-channel mixer, with input #3 being Bluetooth streaming enabled.
Mixers
A fair amount of mid-level mixers provide a Bluetooth input to help make audio streaming painless. The PreSonus StudioLive AR16c has 16 analog mic/line inputs, as well as a stereo “Super Channel” that can play audio via RCA inputs, 1/8-inch stereo TRS input, SD/USB playback or BT 5.0. Moving this idea in a slightly different direction, RØDE Microphones’ RØDECaster Pro II not only provides a Bluetooth audio input, but allows audio from phone calls to be streamed for podcasting. Very clever.
You won’t find many high-end mixers with built-in Bluetooth capability, but that doesn’t mean you can’t take advantage of the technology. A variety of BT “direct boxes” are available that help integrate Bluetooth with existing analog or digital mixers. Radial Engineering’s BT-Pro V2 from is a stereo BT receiver that provides balanced XLR outputs with level control, a reception range of up to 100 feet, and is powerable via phantom or USB-C. The chassis is constructed from 14-gauge steel but employs a plastic insert that allows wireless signals to pass without obstruction.
We could fill an entire issue of FOH telling you about gear that can stream audio via Bluetooth, but here are a few possibilities before we get off the topic of audio streaming: A number of studio monitors feature a BT audio input in addition to the typical RCA/TRS/XLR inputs — a real convenience for situations when a client wants to play audio from their phone in the control room. You’ll find guitar and keyboard amps with a Bluetooth input to facilitate streaming for practice or track playback. And there are plenty of DJ mixers that support Bluetooth audio streaming.
Bluetooth Control
Bluetooth technology becomes a lot more interesting when you look at the ways that manufacturers have used it for remote control of their devices. Some apps allow the same control via BT as is available from the device control panel, while other apps offer access to parameters or functions that are unavailable on the device itself. Across the board, the screen of a smart device is capable of providing far more information and is easier to read than a small LCD screen on a wireless transmitter.
Consider Austrian Audio’s OC818 multi-pattern condenser microphone. The mic has the usual switches on the body for selecting pattern, HPF and pad. The pattern switch has an additional setting ( • ) that sets the mic to “Preset Mode,” and a mini-XLR jack on the mic’s backside accepts an optional BT dongle. Austrian Audio offers a free app that allows remote control over the pattern, HPF and pad from your smart device, so you can adjust parameters while listening to the mic on the source. Further, there are intermediate pattern settings between the “big three” (omni, figure-8 and cardioid) accessible only from the app itself.
JBL’s PRX900 Series of powered loudspeakers employ Bluetooth LE for use with its Pro Connect app that can control DSP for up to ten loudspeakers. Pro Connect can manage speaker names, 12-band parametric EQ, system presets, feedback suppression, and — in case a millisecond resolution is not fine enough for you — speaker delay in 100 µS increments. Pro Connect also provides additional functions that that are only accessible via the app, such as speaker snapshots and groupings.
Sennheiser Evolution Wireless Digital systems can be managed via the company’s Smart Assist app running on iOS or Android devices. Smart Assist provides automated setup of EW-D transmitters and receivers, and can manage frequency allocation, channel naming, audio muting, signal status and battery status. The app monitors RF and audio levels, and can also be used to manually set RF channel of the transmitter and receiver. You can even remotely enable or disable the transmitter mute switch, avoiding the issue of talent accidentally muting their own mic!
Just for the cool factor, Heritage Audio’s BT-500 is a 500-series module that streams audio from a mobile device via Bluetooth and provides a fully balanced stereo output. The BT-500 supports codecs including aptX (aptX LL and aptX HD), AAC and SBC to facilitate streaming at the highest possible level of quality. And it solves the age-old problem of “where did I put that 1/8-inch dongle?”
An emerging use of Bluetooth technology is Auracast Broadcast Audio. Auracast is a method of audio streaming that supports an infinite number of listeners on one stream and can be used for hearing accessibility in applications such as movie theaters, house of worship, conference centers, etc. It allows any receiver to receive an audio signal without connecting and pairing, which means you can share music from your smart device to a number of people located nearby. Auracast would enable people to hear audio from a silent TV in (e.g.) an airline terminal, reducing some of the annoying background noise we’ve all come to expect in such situations. That’s smart.
Steve “Woody” La Cerra is the tour manager and Front of House engineer for Blue Öyster Cult.
