Playing back music in a commercial sound install has changed since the days that CD players, cassettes, and FM radios ruled the world. Alternatives include multi-format CDs, Bluetooth for playback from a computer or smartphone playlist, SD cards, USB memory sticks, and even the web, thanks to streaming services like Pandora and Spotify.
So with all these choices, what do you choose for an install? Well…why not all, or at least most, of them? Ideally, you want a playback device that can handle a variety of CD formats as well as different Bluetooth protocols and solid-state memory, but of course, more functionality raises the price. In any event, whether for bars, restaurants, houses of worship, fitness studios, corporate A/V, theaters, hotels, dance schools, or anyplace else you need audio playback, this family of devices delivers a variety of options.
Beyond Conventional CDs
Any CD player designed for a sound install can play standard audio CDs (officially called CD-DA, for Compact Disc Digital Audio). The main limitation with audio CDs is that they’re limited to 79 minutes of playback time—and you don’t always want to have to change media every 79 minutes. CD players that support data CDs can play back MP3 files, which with a standard 670 MB (74 minute) CD, can do almost 12 hours of unattended playback (assuming MP3 files recorded at 128 kbps). That bit rate is more than suitable for background music, but for music that’s more in the foreground, doubling the bit rate to 256 kbps provides a significant quality increase yet still gives close to 6 hours of uninterrupted playback time.
Other formats supported by some CD players include WAV files, although these generally don’t save space compared to standard audio CD files. However, an advantage of data formats like WAV and MP3 compared to audio CDs is that you can prepare a folder structure of audio files within a computer, and transfer these to a data CD. Then if supported by the player, you can play only files within a certain folder. For example, you could have a folder of background music for lunch, another for dinner, and another for late-night at a bar, and playback music only from within a specific folder.
Cut the Cord with Bluetooth
The big advantage of Bluetooth is being able to connect wirelessly to devices that generate Bluetooth audio, like smartphones, tablets, and computers. However, as soon as you choose to go wireless, it’s necessary to set up the gear in a way that prevents dropped connections. You can usually count on 30 feet for a reliable line-of-sight connection, but any kind of obstacles (walls, people, etc.) between the transmitter and receiver will likely reduce this. Electromagnetic interference can also affect the range.
There are two main Bluetooth “profiles.” A2DP (Advanced Audio Distribution Profile) is universal and required for a transmitting device to transmit audio over Bluetooth. The less-common AVRCP (Audio/Video Remote Control Profile) adds playback control over Bluetooth.
Three common Bluetooth codecs are compatible with the A2DP profile. SBC (Sub-Band Coding) is the most universal Bluetooth codec, and delivers acceptable-to-good audio quality. The aptX codec is a proprietary format designed for higher audio quality. It has two variations, aptX Low Latency for reducing the latency of Bluetooth connections, and aptX HD, which prioritizes audio fidelity. It also includes error correction to maintain good connections, even with the occasional dropout. However, being proprietary, it’s less common and to take advantage of it, both the Bluetooth transmitter and receiver need to incorporate the same aptX codec.
Another codec, AAC, delivers somewhat better sound quality than the default SBC codec. However being mostly associated with Apple-based products, it’s not as common as SBC.
Whether latency is important or not depends on the application. SBC’s latency is around 100 ms, whereas the aptX low-latency connection boasts 35 ms. If you’re streaming Bluetooth audio from a TV in a sports bar, 100 ms of latency can degrade the experience, because the sound will lag the video by a noticeable amount. 35 ms will be acceptable for most people. On the other hand for background music, latency doesn’t really matter if the audio is playing back 100 ms later than what’s being transmitted from a smartphone.
Also, check whether a unit can pair with more than one Bluetooth device. In many cases, you’ll pair to a specific device, and leave it at that. But you might want to pair to a big-screen TV during sporting events, a playlist that you carry around with you that’s stored in your smartphone, and a web radio streaming service playing back on a tablet or computer that’s housed in the facility. Although you can always cancel a pairing and pair to a different device, being able to remember pairing information for multiple devices and having a unit that can switch among these, can save time and offer a more seamless playback experience.
Solid State and Other Options
We’re seeing slots for USB memory sticks or SD cards in a lot of automobiles, and now they’re in install playback units as well. Pay attention to card type and memory capacities. For example, although USB drives routinely go up to 128 GB and more, a playback unit may have a 32 or 64 GB limitation; and there may be different limitations for standard SD compared to SDHC cards. There may also be limits on the number of files and folders a unit will recognize—a typical number is 999 files and 8 folders. Also, note that although Microsoft itself seems to have lost interest in the WMA (Windows Media Audio) format, it’s still alive in many cars, and that format may be supported as well.
Now we have something providing an audio input, but the audio needs to go to your sound system. The usual choices for physical connections are RCA unbalanced or XLR b alanced line out jacks, and possibly S/PDIF digital (coaxial or optical). As to control, a remote can be very handy if the unit is tucked away, out of sight of visitors or customers.
What’s the Right Playback Device for You?
Let’s look at some typical products. Most fall in the $200 to $400 range; it’s a competitive field, so most of the time you’ll be making any purchasing decisions on the feature set more than the price.
TASCAM CD-200BT. This rack-mount unit supports audio and data CDs, as well as the SBC, aptX, and AAC codecs. It also has a front-panel 1.8″ jack for accepting the analog output from portable music players and smartphones. The CD options are particularly well-developed; you can play back from folders, create program selections, do random playback, repeat all tracks within a folder, enable continuous play for audio CDs, and the like. You’ll also find “accessory” features like a pitch control for CDs to speed up or slow down the audio (which also changes pitch), and an “Intro Check” function that cycles through the first 10 seconds of each track to confirm the songs and playing order.
TASCAM CD-200iL. A variation on the CD-200BT, this trades the Bluetooth receiver for a Lightning and 30-pin dock to accommodate both newer and older iOS devices. The CD-200iL also charges a connected device, and does iPod control (album skip, repeat, and playback mode) from the transport. For non-iOS devices, a stereo minijack connects to analog headphone outputs.
Denon DN-F350. This unit drops the CD player to create a playback device with no moving parts: it’s all about Bluetooth, SD cards, and USB memory sticks. The DN-F350 also has a front-panel, XLR connector (with optional phantom power) for applications requiring a mic input like fitness centers and gyms, which can also benefit from a pitch/tempo control of ±15% when it’s important to match a particular exercise rhythm. Outputs include balanced XLR and unbalanced RCA jacks, and because there are no moving parts, the DN-F350 is ideal for situations where the unit would be subject to vibrations that would cause skipping with CDs (although note that many CD players for commercial install have anti-skip buffers, which help mitigate this issue). Omitting the CD player also results in the lowest price tag of the various units listed here.
TASCAM CD-400U. The bottom line on this unit is that it will play back basically anything you throw at it—CD, Bluetooth, SD card, USB thumb drive, and yes, even radio waves thanks to an AM/FM tuner. What’s more, there’s the unique feature of being able to record from a CD or the AM/FM tuner to the SD or USB media. It also ups the ante for connections, with balanced XLR outputs, RCA outs, and a dedicated set of RCA outputs for the AM/FM tuner. For integration into more complex systems, there’s an RS-232C, nine-pin serial port.
Yamaha CD-600BL. This unit emphasizes CD playback, and provides a five-disc CD changer with Yamaha’s patented PlayXchange function for uninterrupted music. However, it also has a port to accommodate USB memory for MP3 and WMA file compatibility, as well as iPod compatibility and an RS-232C interface for custom installations.
Denon DN-500CB. Here’s another unit that plays back CDs (both audio and data types for MP3 files), solid-state, and Bluetooth. There’s a slot-loading CD transport with the expected options (various repeat and random modes), a stereo minijack input to accommodate analog outputs from smartphones and personal music players, and a USB port for memory sticks. With CDs and USB, a ±15% pitch/tempo control allows variable speed. Outputs include XLR balanced and RCA unbalanced line outputs, and there’s an RS-232C port for control via a host in more complex setups.
These summaries include the main features, but of course, all these units have other, specific features that may or may not be important to you. At Full Compass, we’re happy to help guide you toward making the right decision for your needs—feel free to call, and take advantage of our 40-plus years of experience serving the sound contracting business.