This is a device with a user interface allowing you to select music sources (servers), to browse their content and select songs to play.
The source could be internet radio stations or your own music collection on a server in your home network.
They are playback only. Maintaining your audio collection (ripping, tagging, etc.) is done on the PC'
In general they are quit as there are no moving parts inside like disk drives or cpu-coolers.
They rely on the (home) network to access the audio.
Some allow for local playback from a SD card or a USB thumb drive.
To browse and play the content on a server, both player and server must talk the same protocol.
In general UPnP AV / DLNA is used. If not, you are locked into a proprietary protocol.
The player must support the audio formats on the server or the server supports conversion on the fly (transcoding).
The player converts the audio stream to analogue. Digital out might also be supported.
You can connect it to an amplifier.
Some have a build in amplifier. You must supply the speakers.
Players with build in speakers are called internet radio.

Portable player with Airplay
Rechargeable battery
120 Watts digital Class D power amplifier system drives two 2” tweeters and a 4” woofer
EUR 699 / US$799

UPnP compliant network player
| DAC | Wolfson WM8728 24-bit/96kHz capable |
| THD+N | 0.003% @ 1kHz |
| Frequency Response: | 20Hz-20kHz +/- 0.2dB |
| Signal to Noise Ratio: | > 95dB |
| Total correlated jitter: | <200pS |
| Digital Outputs: | S/PDIF Co-axial and TOSLink Optical 16-24 Bits, 22.05-96kHz |
| Audio Formats | WAV containing uncompressed PCM 16-24 bit 32-96kHz, FLAC containing losslessly compressed PCM 16-24 bit 32-96kHz, AIFF containing uncompressed PCM 16 bit 32-48kHz, Microsoft® Windows MediaTM Audio (WMA 9 Standard) 32-320kbps, MP3 (CBR or VBR) 16-320kbps, AAC, HE AAC and AAC+ (CBR or VBR) 16-320kbps, Ogg Vorbis 32-320kbps |
| Streaming Protocols | RTSP (Real Time Streaming Protocol) MMS (Microsoft Media Server Protocol) HTTP (Hyper Text Transfer Protocol) |
| Wi-Fi | IEEE 802.11 b / g or n |
| Wi-Fi Encryption | WEP, WPA, WPA2 |
| Ethernet | IEEE 802.3,10 Base-T or 100 Base-T |
| USB | 2 x USB 1.1 current limited to 500mA each |

Wolfson WM8740 DACs in dual differential mode
24-bit/384kHz upsampling
Inputs
Wi-Fi / Ethernet
S/PDIF optical and electrical
24 /192 asynchronous USB (driver for Win)
Services: Aupeo!, BBC iPlayer Radio, Pandora, Rhapsody, Sirius/XM and MP3Tunes
Remote: Stream Magic Remote app for the iPhone, iPod Touch or iPad

Price: £700 / € 995.00
Due on sale in April 2012

| dlna 1.5 Certified (AUDIO ONLY) |
| Windows 7 Certified |
| Apple AirPlay Certified |
| USB iPod Direct/Flash/HDD |
| Made for iPod/Works with iPhone Certified |
| RadioDenon.com - access to over 12,000 Internet Radio Stations |
| Pandora Radio Streaming |
| Rhapsody and Napster Streaming |

DAC (digital-to-analogue converter), stereo preamplifier and stereo power amplifier in a single chassis.
WiFi
The initial release of the Devialet AIR Application works with:


Technical specifications
ternet radio 169,00 USD
Wireless digital internet radio and MP3 player
• Plays internet radio without the use of a computer
• Streams MP3 music from your computer or network
• Supports over 10.000 radio stations, including BBC 1,2,3,4 and 5Live
• Supports MP3, WAV & WMA
• Alarm clock functionality
• Live RSS feeds / Blog feeds in display
• Built-in speaker and WLAN antenna
• Stereo audio out (2 x cinch) to connect to amplifier set
• Line out (mini jack ) to connect to headphones or active
speakers
UPnP-streamer
Room correction
No moving parts
Supports up to 32bit and 192kHz
All common audio formats.
TouchPanel
Remote by Web-Browser (WLAN-Handy/iPod/iPhone...)


Linn’s first attempt at streaming audio players was the Klimax DS
Today they have a range of UPnP players:
| Klimax DS Player | $18,500. |
| Akurate DS Player | $6,850. |
| Majik DS Player | $3,500. |
| Sneaky Music DS Player | $2,000. |
Network: ethernet
Protocol: UPnP™ AV 2.0
Formats: up to 24-bit/192 kHz native sample rate, FLAC, WAV, MP3 & AIFF
Analogue audio outputs: RCA / XLR
OS: RTEMS
Open source: http://oss.linn.co.uk/


UPnP compliant media player
Pre-amp
Remote control
Inputs
Audio formats
Networking
WPL Windows Play List via UPnP media server
JPEG Still picture files
HTTP/1.1 Audio Transport
Shoutcast ICY Metadata support
WMA Streaming (including MMS and WMS)
RTSP/SDP (Real Time Streaming Protocols) over TCP
Connectivity
Ethernet - 10Base-T/100Base-T
Wireless-LAN - IEEE 802.11b/g
Module HW is IEEE 802.11n prepared, FW WiFi 802.11 compliant
WPA
WPS WiFi Protected Setup Pin and push button supported
Interface: Stream 700 by Stream Unlimited


Network: ethernet/Wlan (WEP/WPA)
Protocol: DLNA/UPnP
Output: 1x analog (RCA), 1x optical Toslink, 1x S/PDIF coaxial cinch
Audio format: WAV, FLAC, MP3 (128 to 320 bit/s)/ Internet radio
4.3" wide-aspect ratio, colour touch-screen(480 x 272 pixels)

Protocols:
Inputs:
Output:
iPhone and Android Control Application
Price: $699

• Audiophile grade 24bit/192hkHz highend audio streaming client
• Ethernet & WLAN
• UPnP & DLNA support
• USB input for flash memory and hard disk drives
• USB input for Apple devices using digital out
• Internetradio with automatic detection of local stations
• “Gapless“ playback for all formats
Wireless music system build on Open Source software.
Operating system is Linux with GStreamer multimedia foundation.
Network: WLAN 802.11g
Protocol: UPnP-AV/ DLNA with Raumfeld extensions.
Supported formats: MP3, WAV, FLAC, OGG Vorbis, ASF, WMA, AAC (containing AAC and apple lossless).

Controller € 398,-
Base € 279,-
Music server and access point.
160 GB HD
Extendable via USB 2.0 HD

Connector € 285,-
Wireless Digital-Analogue Converter:
Cirrus Logic™ DA Converter. 96 kHz, 24 Bit
Input:
Output: RCA (Cinch), Spdif / Toslink
USB 1.1

Speaker M € 749,-
Active speakers with ART tweeters and 5" Rohacell woofers supplied by ADAM Audio.
DAC:Cirrus Logic™ DA Converter. 96 kHz, 24 Bit
Cirrus Logic™ DA Converter. 96 kHz, 24 Bit
Input:
USB 1.1

Resolution |
24 bits, no sample rates specified |
Networking |
Ethernet 10/100, 200MB/s PowerLine Homeplug AV |
Interface |
Controller software for PC/Mac, iPhone, iPod Touch. |
Digital inputs |
network, USB port |
Digital out |
no |
Analog in |
RCA, 3.5 mm stereo jack |
Analog out |
RCA, , 3.5 mm stereo jack |
Operating system |
not specified |
Streaming protocol |
not specified |
| Audio formats | MP3, AAC, WAV, AIFF,FLAC ALAC |
Expected to be introduced fall 2011 starting at £500.


100 Watt amp
Protocol: UPnP/Internet radio/file sharing
Network: Ethernet/Wi-Fi


Also available with build in amplifier.
Network: ethernet/Wlan. First unit must be connected to router using a cable or you use a ZoneBridge for an all wireless setup.
Number of tracks limited to 65.000
Protocol: CIFS / SMB (file sharing) to access NAS/PC/Mac
Output: Analog (RCA) and digital out (Toslink/coax)
Audio format: MP3, WMA (WMA Lossless and WMA Pro are not supported), AAC (MPEG4), Ogg Vorbis, Audible (Format 4), Apple Lossless, FLAC, WAV, AIFF
Resolution: 16 bit / 48 kHz
Internet radio: RadioTimes, MP3 and WMA streaming audio formats

One of the first streaming audio players by Slimdevices.
Looks like Logitech stopped producing them but it is a classic indeed.
Squeezeboxes use their own proprietary protocol.
You need an computer in your home network running SlimServer/SqueezeCenter/Squeezebox Server /Squeezebox Server or what ever new name Logitech marketing department conjectured up to access your own music collection.
Often a NAS is used like the Vortex box

Soundcheck's - audio@vise for some serious tweaking.
Connecting a USB DAC by John Swenson
Measurement of the SPDIF out - Anedio

High end version of the SqueezeBox.
Protocol: proprietary streaming protocol, requires SqueezeCenter software to play your own music.

Network: ethernet/Wlan
Protocol: DLNA/UPnP
Output: Line out, headphones out, S/PDIF digital optical out 44.1/48 kHz
Audio format: MP3, OGG, WMA, WAV / Internet radio
Touchscreen 3.5" colour LC display for function and track information
(ID3 tags, album cover, file name etc.)

| Media Server | Twonky media manager (DNLA) & local playback via USB |
| Supported formats | AAC, MP3, OGG, WMA, WAV, FLAC up to 24Bit/96kHz Line-out up to 16Bit/48kHz |
| Other functions | Control via Remote of WAP-8600 or WAP-9500 |
| Integrated power adaptor | |
| Internet radio and podcast | |
| Internet radio station access by vTuner (Full version with more than 10 000 stations), favourite list and via USB storage contents | |
| Supports FAT32 and NTFS file systems | |
| Power adaptors with international plugs EU,GB,US, AUS (Typ A,C,G,I) | |
| Network connection | WLAN 802.11n (wireless) or LAN (ethernet cable), UPnP and DLNA compatible client |
| Ports | SATA, iPod-dock, headphones, Line-In, Bass/Treble/Level control, SPDIF, USBx2, RJ45, speaker, AC input |
| Line-out | active subwoofer, headphones out, S/PDIF digital, optical out 44.1/48kHz |
| Frequenzy range | 20-20.000 Hz |
| S/N | >95dB |
| Accessoiries, not included | iPod/iPhone-dock, USB stick for FM radio |
| Dimensions | 350 x 246 x 65 mm |
Also available with ICEpower amplifiers
Network: ethernet/Wlan
Protocol: UPnP
Formats: MP3, WMA, LPCM, WAV, FLAC, AAC, OGG-Vorbis
A box having both digital and analogue inputs sending the audio over ethernet or Wi-Fi to powered speakers.


THIEL SCS4 powered speaker with Wi-Fi and ethernet inputs only!

The zöet was announced in 2008 but as far as I know not on sale yet.
A partnership between THIEL en Olive was announced early 2010.
DLNA compliant audio player
DLNA software: TwonkyVision
Network: ethernet
Remote: yes +iPhone app.
| File Support | Type | WAV, WMA, FLAC, MP3, AAC |
| Audio Sample Rates | 96, 88.2, 64, 44.1, 32, 24, 22.05, 16, 12, 11.025, 8 (kHz) | |
| Word Deptth | 16, 24bit | |
| Support Services | Internet Radio | vTuner |
| Connection | Analog Output | RCA 2ch, XLR 2ch |
| Digital Audio Out | Yes (optical / coaxial) | |
| User Interface | Web Browser | Java Script - compatible browser (IE, Safari, etc.) |
| Play Back of iTunes Library | With TwonkyMedia server | |
| FL Display | Full Dot Matrix for English, German, French, Russian, Spanish, Japanese | |
| Certification | Windows7 | Yes |
| DLNA | Yes(Ver.1.5) | |
| Size (W x H x D) | 17−1/8″ x 2−3/4″ x 17−3/8″ | |
| Weight | 26.5 lbs. | |
| Digital Outputs | 1 AES/EBU, 1 Coaxial, 1 Optical |
Digital I/O |
1 LAN, 2 USB |
Control |
via iPad and front panel |
HDD Memory |
Up to 2 terabytes |
SSD Cache |
40G |
Formats |
WAV, FLAC, APE and others |
Power |
220V AC or 110V AC |
Dimensions |
430mm x 96mm x 353mm |
Weight |
13kg |