Dual Channel Wireless Audio With Your iPhone or iPad

Wireless Audio For Mobile Is Catching On

These days, more and more people are using their smartphones and tablets for video production. And why not? The cameras are getting better and better, and just about everybody has one.

Shooting video with your iPhone is easy, but getting good audio is a little trickier. That’s why Azden started their i-Coustics® line of audio products, compatible with smartphones and tablets, so even mobile device users had an option to improve their video’s audio quality at an affordable price.

But one of the most common questions Azden gets from end users about the i-Coustics® products goes something like this: “So if I buy a second transmitter I can record two people at the same time in an interview?”

Unfortunately, the answer is no. To record two transmitters simultaneously you’d need a dual channel receiver. Azden does make a dual channel receiver for PRO Series transmitters, but using it with a mobile device requires a bit of a work-around.

Azden’s Dual Channel VHF Wireless Systems

Azden currently offers two complete dual-channel VHF wireless kits: the WDL-PRO, which comes with 2 belt-pack transmitters and lavalier microphones, and the WDM-PRO, which comes with one belt-pack/lavalier and one handheld transmitter. The key to the dual channel feature is Azden’s WR32-PRO dual-channel receiver which comes with both of the previously mentioned kits but is available for separate purchase.

The nice thing about the  WR32-PRO is that is compatible with all other PRO Series transmitters. So if you already own a WLX-PRO, WMS-PRO or WHX-PRO kit, then you have one compatible transmitter. You could then pick up the WR32-PRO and a second PRO Series transmitter (WL/T-PRO or WM/T-PRO) and make your own dual-channel kit for a little less money.

Once you have the WR32-PRO and two PRO Series transmitters you’ll be ready to record dual-channel audio to a camera, but there’s one more challenge to overcome in order to record dual-channel audio into a mobile device.

The Challenge With Dual Channel Audio Into A Smartphone

You can think of a dual channel wireless receiver as two single channel receivers crammed into one. Each receiving frequency needs its own audio output. That’s why all of Azden’s dual channel receivers use a stereo output cable: the signal from one transmitter is output on the left side and the other on the right side.

If you were to listen with headphones you’d hear one microphone in each ear. In a video recording, this allows for each microphone to be recorded separately on its own “track,” facilitating audio editing of each speaking subject in post production.

This works great when plugging into a camera’s microphone input (which are usually stereo inputs) but the problem with mobile devices is that they only have a mono microphone input. If you plug a stereo audio output into a mono input you’ll only be able to hear audio on the left channel. That means channel 2 (right) will not be recorded!

To make matters even more complicated, smartphone and tablet manufactures usually integrate the microphone input with the headphone output jack, which means you also need a specialty connecter to hook up an external microphone (or wireless unit).

The Solution

The solution to this problem is actually very simple and inexpensive. All you need to do is purchase an audio cable and an adapter cable.

The audio cable you’ll need is called the STM Cable and it will take the two channels of audio from the WR32-PRO and sum them to mono for use with a smartphone or tablet. The cable will need to replace the stereo audio output cable that came with your dual-channel receiver.

The adapter cable you need is called the HX-Mi TRRS Mic/Headphone Cable. This will allow you to tap into the microphone input of your mobile device.

Here’s how to hook everything up.

(1) Plug the straight end of your STM Cable (with 2 black stripes on the tip) into the “MIC OUT” jack of the WR32-PRO.
(2) Plug the right-angle end of your STM Cable (with 1 black stripe on the tip) into the “ECM” jack of the HX-Mi adapter.
(3) Plug the male end of the HX-Mi (three black stripes) into the headset input of your mobile device.

And that’s it! Now when you record video with your iPhone or iPad you’ll be able to hear both transmitters. This will work with most Android phones too, including the Samsung Galaxy, Tab and Note models.

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