Radio World Magazine - January 16, 2008
by Edward C. Dulaney
Feed Mixer Output Into JK Audio’s Wireless Interface, Connect with Cellphone to Ease Remotes
Every so often a device comes along that makes you want to say, “Why didn’t I think of that?” Joe Klinger at JK Audio has developed such a device.
Called Daptor Three, this little black box transmits audio over a Bluetooth link. What that means for the average user is that they can take the output of a mixer, feed it into the Daptor Three and connect with their wireless phone for a fast, easy remote broadcast.
I took the unit home with me, and connected it up to the output of my Autogram MiniMix-8 that I use for production at my house. I then took the audio from the Daptor Three and connected it to my external “Air Monitor” input. This gave me a good testing platform for evaluating the audio quality of the Daptor Three.
Connecting the Daptor Three with a cellphone is a pretty straightforward operation. Simply configure your cellphone to look for a Bluetooth adapter, and hold the silver button on the Daptor Three down for about five seconds. Doing so will signal the Daptor Three that you wish to sync it with another Bluetooth device. Within about 30 seconds my phone signalled that it had located the Daptor Three and was ready to connect.
I then started recording the audio from my home studio into a computer at my workplace. Oh, the marvels of modern technology.
From my home I could bring up a VNC connection to a production computer, start the recording and then listen to what I recorded as an MP3 file. What I heard on the recording that I made amazed me. The quality was much better than a typical cellphone call. There was a bit of digital “grunge” on the connection, but that has to be expected over any CDMA or GSM cellular connection.
Do not, however, expect to broadcast a music segment using this box. As is typical with cellphone calls, music does not transmit over the connection with any level of fidelity at all. Anyone who has listened to music-on-hold sources while on a cellphone knows how poorly music sounds.
That brings me to another small problem with the Daptor Three. If you are using the return channel as a simple IFB, then you should experience no problems whatsoever. If, however, you try and send music down the return channel it will cause some significant problems.
With most cellular providers, the bandwidth available on any given call is divided between the two connected parties. If the station is sending music down the IFB channel, the audio from the remote back to the studio will have significant audio degradation. This isn’t a limit of the Daptor Three, but a limitation of cellular providers.
The next test I tried was configuring the Daptor Three to talk to a USB Bluetooth interface on my PC. Just as with my cellular phone connection, the PC’s adapter easily synced with the Daptor Three. Unfortunately, my USB adapter would not permit me to send audio from the Daptor Three to the PC at full 20 kHz bandwidth. I was limited to 3.4 kHz. According to Klinger, the newer version of PC Bluetooth adapters will not have this limitation.
I could, however, send high-quality audio from my PC to the Daptor Three. While there were some slight artifacts on the audio, the quality was more than acceptable for general use. I can see this being used to get audio from laptop computers into a production board without having to run wires out of the laptop.
The only real downside I found with the Daptor Three was the lack of a miclevel input on the box. The audio must be fed into the unit at line level. This omission precludes its use as a man-on-the street interview box.
According to Klinger, “Adding a mic input means adding a mic pot ... and probably a decent headphone amp and level pot. We’ve learned from experience that it’s never as simple as you would hope.” Perhaps the folks at JK Audio will consider something like this in the future.
The Daptor Three started shipping in August and will likely still go through a refinement or two. Klinger already has indicated that an upgrade will be available when the Bluetooth technology for bidirectional Hi-Fi audio using a PC adapter is available.
He observes that the trend has been for PC manufacturers to support only a “headphone” mode with their USB and PCMCIA adapters, but he also has said, “We are working to reverse the trend by offering (at no cost) a software update that will allow either ‘cellphone’ emulation, or headset emulation.” It is clear to me that JK Audio is willing to do everything possible to stay one step ahead of the technology curve.
Overall I’d recommend this little box to anyone who needs another useful tool in their arsenal of remote gear. For those days when the sales guy sells a remote at the annual cow-herding festival in PawPaw County, this might just be the device you need to pull that remote together.
Daptor Three Wireless Audio Interface
Bluetooth link eases remote broadcasts
Audio quality trumps that of a typical cellphone call
Lack of a mic-level input on the box
Music does not transmit over the connection
Sending music down the return channel causes problems
Ed Dulaney is the chief engineer for Crawford Broadcasting in Denver.
For more information, including pricing, contact JK Audio in Illinois at (800) 552-8346 or visit www.jkaudio.com.