Pointers for Finding the Best Wireless Audio Transmitter Product for Whole-Home Audio Streaming

Recently more and more wireless audio transmitter devices have emerged which promise to deliver the ultimate freedom of broadcasting music throughout the house. We will have a look at numerous products and technologies to find out in how far these products are practical for whole-house audio uses and what to look out for when buying a wireless system.

Getting audio from your living room to your bedroom can be quite a problem in particular in homes which are not wired for audio. There are several technologies solving this problem. These include infrared wireless, RF wireless, wireless LAN (WLAN) and powerline.

Infrared is limited to line of sight since the audio signal is broadcast as lightwaves and therefore products using this technology, such as infrared wireless surround sound products, are restricted to a single room.

RF wireless products broadcast the music as RF waves - either by using FM transmission or digital transmission - and can as a result easily transmit through walls. FM transmitters are the cheapest alternative. They offer good range but the music signal is prone to audio distortion and hiss and is extremely susceptible to interference from other wireless transmitters.

Digital wireless audio transmitter products, such as products from Amphony, make use of a digital protocol. The audio is first converted to digital data before being broadcast. Some wireless audio transmitters will use audio compression, such as Bluetooth transmitters which will lower the audio quality to some degree. Digital wireless audio transmitters which broadcast the audio uncompressed offer the highest audio fidelity.

Products using wireless LAN are useful when streaming audio from a PC. Their downside is that they typically have some fairly high latency, i.e. the signal will be delayed by some amount since wireless LAN was not specifically designed for real-time audio streaming. WLAN receivers often do not have built-in network access. As a result, such devices often require purchasing separate LAN cards. These cards are then plugged into each receiver.

Powerline products broadcast the audio via the power mains and provide large range. They run into trouble in houses where there are individual mains circuits in terms of being able to cross over into another circuit. Another challenge confronting powerline products are strong power surges and spikes. Such surges can cause dropouts in the audio due to errors in the transmission. To safeguard against these errors, powerline products normally build a delay of several seconds into the transmission.

Here are some suggestions for picking the optimum wireless audio system: Try to find a system that can run several wireless receivers from a single transmitter. Ideally an unlimited number of receivers should be supported. That way you don't need to purchase additional transmitters when you begin adding receivers in different rooms of your house. Some products have some form of error correction built in which will help guard against dropouts in case of strong wireless interference. Choose a digital RF audio transmitter to make sure that the audio quality is preserved. Make sure the audio delay is smaller than 10 ms if you have a real-time application such as video.

Pick a transmitter that has all the audio inputs you need, such as speaker inputs, line-level RCA inputs etc. Make sure that you can buy additional receivers later on as you expand your system. Check that you can get receivers with speaker outputs for connecting regular loudspeakers as well as receivers with line-level RCA outputs. Because you may want to connect the transmitter to several sources, you should select a transmitter that can be adjusted to different signal volume levels to prevent clipping of the audio signal inside the transmitter converter stage.

Make sure that the amplified wireless receivers have built-in digital amplifiers with low distortion figures. This will keep the receiver cool due to high amplifier power efficiency and offer optimum sound quality. Choose a system which provides receivers that can drive speakers with the desired Ohm rating. Make sure the receivers have a small form factor and are easily mountable. This will help during the installation. Devices which operate in the 5.8 GHz frequency band will have less problems with wireless interference than products utilizing the crowded 900 MHz or 2.4 GHz frequency band.