By Full Compass LivePlaying back music in a commercial sound install has changed since the days that CDDefinition:
CD (Compact Disc): An optical-based, disc-shaped digital recording and playback medium. players, cassettes, and FMDefinition:
FM (Frequency Modulation): A method of transmitting audio with minimal noise. The waveform being modulated is called the carrier and the modulating waveform, the modulator. radios ruled the world. Alternatives include multi-format CDs, BluetoothDefinition:
A short distance (less than 33 feet) wireless data transfer standard. for playback from a computer or smartphone playlistDefinition:
1. A list of what programming is in rotation at a radio station. 2. A sequence of songs created by consumers for playback. 3. A feature of some DAWs that allows playing songs created in the DAW sequentially., SD cards, USBDefinition:
(Universal Serial Bus) A standard, bi-directional serial connection between computers and peripheral devices. memory sticks, and even the web, thanks to streamingDefinition:
A method of sending a continuous flow of digital content over IP (Internet Protocol) networks, and often, tailors itself to the user's receiving capability. services like 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-DAD, for Compact Disc DigitalDefinition:
A signal or data expressed as series of the digits 0 and 1, typically represented by values of a physical quantity such as voltage or magnetic polarization. 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 dataDefinition:
Information used by a computer in order to arrive at a decision. Although this is a plural term, it's often treated in the singular. CDs can play back MP3Definition:
A lossy digital compression coding format for audio, derived from the MPEG-1 and MPEG-2 formats. Audio compression can range from a data reduction ratio of 200:1 to broadcast quality (i.e., no noticeable audio degradation for the vast majority of listeners). MP3 streaming rates vary from 16 kilobit per second to 320 kilobits per second for stereo. Audio stored digitally in the MP3 format will have the .mp3 file extension. 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 rateDefinition:
The number of bits (pieces of data) that passes per second, usually Mbit/s. is more than suitable for background music, but for music that's more in the foreground, doublingDefinition:
In recording, the effect created by playing a part and then overdubbing a part over the first part, with the second played as similarly as possible to the first part. This effect is also simulated with delay lines (see DDL or Digital Delay Line). 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 WAVDefinition:
(Waveform Audio File) Audio bit stream file format developed by IBM and Microsoft. 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 gearDefinition:
Musical or performance equipment. 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 transmitterDefinition:
Any device that sends an electrical signal, typically radio waves or by wire. 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 RemoteDefinition:
A broadcast from the field, not from the studio. A Remote Control. Control Profile) adds playback control over Bluetooth.
Three common Bluetooth codecs are compatibleDefinition:
Capable of operating with a particular selection of hardware or software. with the A2DP profile. SBC (Sub-BandDefinition:
A grouped range of frequencies, usually with a commonly used designation. Coding) is the most universal Bluetooth codecDefinition:
Codec (COder-DECoder): A hardware device or software routine that digitally encodes audio or video signals for transmission or recording, then decodes them on reception or playback., and delivers acceptable-to-good audio quality. The aptXDefinition:
aptX (audio processing technology X): A Qualcomm codec used for wireless audio primarily with Bluetooth typically between smartphones and sound and automotive accessories. codec is a proprietary format designed for higher audio quality. It has two variations, aptX Low LatencyDefinition:
The amount of delay a signal, data, sound, video, or control signal acquires within a device, system, or long-distance connection. 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 dropoutDefinition:
Momentary loss of a signal in a recording, wireless transmission, or stream.. 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, AACDefinition:
(Advanced Audio Coding): An audio coding standard for lossy digital audio compression, standardized by ISO and IEC., delivers somewhat better sound quality than the defaultDefinition:
A value assumed initially by a device, particularly a computer-based device, until changed. 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 cardDefinition:
(slang) A circuit board that contains circuitry and plugs into an edge connector. 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 RCADefinition:
(Radio Corporation of America) Known for the (RCA) phono plug and jack, among many other inventions. See Phone Plug. See Phono Jack. unbalancedDefinition:
A two-conductor signal connection where one wire connects to ground. Unbalanced connections are prone to ground loop hum if equipment is not in close proximity. or XLR balanced lineDefinition:
A pair of wires, usually twisted with equal and opposite signals, and designed to cancel noise and crosstalk. See Balanced Line. out jacks, and possibly S/PDIFDefinition:
(Sony/Philips Digital Interconnect Format) A protocol for a stereo digital audio connection, based on AES3, that uses coaxial cable or TOSlink optical cables. 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. 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.
Denon DN-300Z. Combining the best of discDefinition:
A storage medium, typically applied to optical-based media (CD-ROM, DVD-ROM, Blu-Ray, etc.)., wireless, and solid stateDefinition:
In electronics, making use of semiconductors like integrated circuits, transistors, diodes, Ices, and the like instead of vacuum tubes. media playback, the Denon Professional DN-300Z is an all-in-one audio player you can count on when the whole room is listening. Ideal for front-of-house, education, music and rehearsal studios, houses of worship, restaurants, and more, it has an answer to every request—all consolidated into a compact 1RU design. Front-loading media slots (CD with single-play mode, USB, SD/SDHC) deliver intuitive playback of today’s familiar mass-storage mediums or go wireless with long-range Bluetooth® audio connectivity (up to 100ft) and instant recall of up to 8 devices such as smartphones and tablets.
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 dedicatedDefinition:
Designed or used to do a specific task or set of tasks. set of RCA outputs for the AM/FM tuner. For integration into more complex systems, there’s an RS-232C, nine-pin serial port.
Tascam SS-CDR250N. A 2-channelDefinition:
1. In radio, television, citizen's band radio, and other wireless communications modes, a specific frequency for communication. 2. In mixers and video, an input or output signal path with controls. 3. In MIDI, one of 16 data paths. solid state/CD recorder/player that comes with a variety of remote control options, designed for network applications. It's the ideal SD card recorder/player, having a variety of features with extensive terminal equipment applications and business applications. An FTPDefinition:
(File Transfer Protocol) A method of transferring large files over a network. client function is added which enables the exchanges of sound source data with others via server communication. You can also keep the starting time accurate for recording and playback based on time management via SNTP. An optional IF-DA2 Dante® card (sold separately) allows the unit to operate on a DanteDefinition:
Dante™ (Digital Audio Network Through Ethernet): The audio-over-IP standard created by Audinate (layer 3). audio network.
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 (800-356-5844, M-F, 7-5:30 CT), and take advantage of our 40-plus years of experience serving the sound contracting business.
