Review: Household wireless audio transmitters

With the homogenization of radio stations, wouldn’t it be nice to take back the airwaves? With all your music loaded on your iPod—or your computer—why not broadcast your own tunes, even if it’s only from the office to the living room? A variety of wireless technologies will get your audio from point A to point B and each method offers unique trade-offs. I recently tested four systems designed to do just that by wirelessly transmitting audio around the house.

Whole House Transmitter

One of the most popular methods of wireless audio transmission is to use FM radio frequencies. Like the products in our recent roundup of FM transmitters for the iPod, TAW Global’s $90 Whole House Transmitter’s signal can be received on a common FM radio, eliminating the need for a specialized receiver unit. The Whole House Transmitter is roughly the size of a deck of playing cards at 3.4-by-2.5-by-0.75 inches. The unit is versatile in terms of power sources, with the ability to run on three AA batteries or any of three included adapters: A/C, USB, or car accessory (“cigarette lighter”) jack.

A stereo minijack audio input at the top of the unit is used to connect your audio source. A retractable male-to-male miniplug cable ships with the unit and can be used to connect an iPod or any other audio device with a minijack output. An RCA adapter cable is also included, so the unit can be used to transmit the audio from home stereo components, as well.

Three sliding switches on the side of the Whole House Transmitter are used to set the FM channel. The unit offers a limited selection of only 7 pre-defined broadcast frequencies, ranging from 106.7 to 107.9.

The Whole House Transmitter was disappointing in terms of audio quality. The sound exhibited a good deal of hiss over each of the unit’s possible broadcast frequencies. The limitations of the unit’s FM audio quality were especially apparent when compared side-by-side with the clearer and fuller sound of the Bluetooth and 2.4 GHz units, below.

TAW Global offered some troubleshooting tips and even sent out a second transmitter to test, but the sound quality of the second unit was comparable to the first. Interference may be blame: TAW Global told Playlist that “hiss is [usually] from interference generated by electrical noise in the building [or] other transmitters near by.” Unfortunately, today’s houses are more likely than ever to have such electrical and radio noise. Fortunately, TAW Global offers a “30 day no reason needed return guarantee.”

iHiFi Receiver and Transmitters

Similar to the Logitech Wireless Audio System for iPod and the Belkin TuneStage we’ve reviewed previously, Zoom’s $200 iHiFi transmits audio using the Bluetooth wireless standard. The iHiFi Receiver can be purchased alone or bundled with one of several transmitters. I tested both the universal transmitter—which works with any iPod or any device with a 1/8-inch stereo headphone jack—and one designed to work with either third- or fourth-generation iPods . (An iPod mini transmitter is also available.) The universal transmitter is powered by a built-in rechargeable battery; the 3G/4G iPod model is powered by the iPod’s remote/headphone jack, which means it reduces your iPod’s battery somewhat.

The iHiFi receiver has a round base—slightly smaller than the diameter of a CD—with a fixed antenna in the center. The power switch is located on the back of the unit, along with both minijack and RCA outputs for connecting the receiver to a home stereo or powered speaker system. A splitter is included to allow the receiver’s power cable to double as a charger for the universal transmitter.

Since the iHiFi transmitters are small and do not need to be tethered to A/C power, they are ideally suited for moving around the house. Because you can easily carry your iPod around, you can use the iPod’s familiar user interface as a “remote control” to control the music playing on your home stereo.

Zoom claims the range of the transmitters is up to 70 feet. Although the universal transmitter performed well throughout my house, the iPod transmitter began to drop out in as little as 15 to 20 feet from the receiver when obstructed by walls. Additionally, both transmitters tended to drop out due to interference when a microwave oven was used nearby. However, when located in range, and away from interference, the iHiFi system produces a clean sound, far superior to the FM signal of the Whole House Transmitter.

MP3 AirLink

StarTech’s $109 MP3 AirLink system transmits audio using the 2.4 GHz frequency spectrum, similar to some cordless phones and wireless network devices. The transmitter and receiver are almost identical, each measuring 3.15-by-3.15-by-0.91 inches, and each hosting a power-input jack on the back along with a single stereo minijack as their respective input and output jacks. The transmitter also has a single button on the top for switching between eight available channels. Like the Whole House Transmitter, the MP3 AirLink is designed to be used with any audio device with either minijack or RCA stereo outputs. Using the included cables, you connect the transmitter to your audio source—an iPod, a computer, or the like—and connect the receiver to your stereo system or powered speakers.

StarTech claims a range of up to 100 feet. Although the system performed as advertised in terms of range, interference was a problem. Running a microwave oven nearby caused the signal to drop out. In addition, several of the MP3 AirLink’s channels interfered with my laptop’s 802.11g wireless connection, sometimes causing it to drop completely. The system’s simplified design compounded the problem, since there’s no way to tell what channel the unit is on. In addition, there’s no power switch on either the transmitter or receiver, meaning both units consume power regardless of whether they are in use or not. That said, when I did get an interference-free connection, the MP3 AirLink produced clear sound.

The AirLink system also supports multiple receivers; you can purchase additional receivers and connect them to additional stereo systems in order to listen to the same music in multiple rooms/locations (provided each is in range of the transmitter, of course).

iCast System

The transmitter and receiver units of Soundcast’s $299 iCast System are the largest of the units reviewed here, each roughly 6.75 inches wide, 3.5 inches deep, and 2.1 inches high at the center. The top of the transmitter unit has a power indicator light and an iPod dock cradle; six different dock adapters are included to accommodate 3G, mini, 4G, color/photo, nano, and fifth-generation iPod models. The back of the transmitter features a power input jack, a three-position channel switch, a 1/8-inch headphone jack, and a power input. The headphone jack doubles as an audio input when no iPod is docked, so the unit can actually be used, with the right cable, to transmit from any audio device with stereo output.

When an iPod is docked in the transmitter, the iPod’s controls function normally, except for the volume level; the iCast system grabs the line-level audio from the iPod’s dock-connector port. The transmitter also charges your iPod while the player is docked, but lacks any data connection, so it does not have the ability to sync your iPod with your computer.

The iCast receiver has a power indicator light along with three buttons for play/pause, forward, and back. Unfortunately, as with many other iPod-dock accessories, you can’t navigate your iPod’s menus, so navigating within large playlists can be a hassle; you’ll want to use the iPod’s own controls for that. The back of the receiver provides stereo RCA outputs, a three-channel selector to match the one on the receiver, and a power input.

Like the MP3 AirLink, the iCast System uses a 2.4 GHz signal to transmit, but the iCast transmitter and receiver employ a technique called direct-sequence spread spectrum (DSSS), designed to avoid interference. And in fact the iCast exhibited none of the interference problems of the other systems reviewed here, while offering up top-notch sound. Despite plenty of equipment that might create interference, the system transmitted clear audio—from the far corners of the house, supporting Soundcast’s claims of a 350-foot signal range.

The lowdown

With iPod-specific features, the iHiFi and the iCast have the most to offer those looking to transmit iPod-hosted audio. The small, untethered design of the iHiFi transmitters are well suited for roaming around the house while using the iPod itself to control your listening experience. On the other hand, the iHiFi’s limited range, especially through walls, may keep you from roaming very far. If you need to transmit your music between two fixed points and each point can remain tethered to an A/C outlet, the iCast is more for you—its clear sound and resistance to interference provide a quality listening experience over a significantly longer range. (It’s noteworthy that these two products were also the most expensive.) If you need to use FM-radio technology, the Whole House Transmitter will do the job, although its performance in my testing wasn’t encouraging. Similarly, StarTech’s MP3 AirLink is much less expensive than the better-performing systems, but in this case, you apparently get what you pay for.

[ Matt Vance is a technology consultant, Web developer, and freelance writer living in Austin, Texas. ]