Many FlexRadio users love to use "studio" or "professional" microphones to operate their Flex Radios.
These microphones are available from multiple suppliers, such as Audio Technica, Behringer, Electro Voice, Heil, Rode, Sennheiser, Shure, and others.
The common feature of most of them is that they use the industry standard 3-pin XLR Connector and Balanced cable. This provides RF Shielding and electrical noise rejection for the microphone input. A desired feature in an RF-rich environment.
Connecting these microphones to the FlexRadio is a simple matter: It requires one of three cable options:
The 6400/6600/8400/8600/Aurora-510/Aurora-520 radios (and their "M-Model" counterparts) ALL have a "Pseudo-Balanced 1/8-inch TRS MIC jack.
The 6500/6600/6700/8600/Autora-520 radios ALL have a 1/4-inch BALANCED Mic Jack.
The 6500/6700 have a dual-use XLR/TRS (1/4 inch) Connector on the back of the radio.
Here is how to connect an XLR Microphone to these radios:
Connecting to the 1/8-inch TRS "Pseudo-Balanced" Jack.
(6400/6600/8400/8600/Aurora-510/Aurora-520 radios)
You will need to purchase or build a BALANCED 3-Pin XLR Female to 1/8-inch (3.5 mm) TRS Cable.
The Cable will need to be wired like this:
XLR > > > > > TRS
Pin 1 (GND) > > > SLEEVE
Pin 2 (Mic+) > > > TIP
Pin 3 (Mic-) > > > RING
These can be purchased from Online sellers and suppliers such as Sweetwater.com GuitarCenter.com or the
Big-box mail order houses.
CAUTION: You MUST be sure the cable is wired as above, and is TRULY BALANCED. Many of the cheap ones made overseas are designed for use by podcasters with computers, not with professional audio equipment, and are not balanced. They often short Pin 1 and Pin 3, which negates the noise rejection of the balanced Mic, or will simply not work properly.
Connect the XLR Female end of the cable to your Microphone.
Plug the 1/8-inch TRS Plug into the MIC Input of the radio.
In SmartSDR, Select "MIC" for the Radio's Microphone Input.
PTT: You will need to provide your own Foot-Switch or Thumb-Switch for PTT. Connect that to the RCA PTT Jack on the back of the radio.
Connecting to the 1/4-inch TRS Balanced Jack.
(6500/6600/6700/8600/Autora-520 radios)
You will need to purchase or build a BALANCED 3-Pin XLR Female to 1/4-inch TRS Cable.
The Cable will need to be wired like this:
XLR > > > > > TRS
Pin 1 (GND) > > > SLEEVE
Pin 2 (Mic+) > > > TIP
Pin 3 (Mic-) > > > RING
These can be purchased from Online sellers and suppliers such as Sweetwater.com GuitarCenter.com or the
Big-box mail order houses.
CAUTION: You MUST be sure the cable is wired as above, and is TRULY BALANCED. Many of the cheap ones made overseas are designed for other purposes, have poor quality control, and are not balanced. They often short Pin 1 and Pin 3, which negates the noise rejection of the balanced Mic, or will simply not work properly.
Connect the XLR Female end of the cable to your Microphone.
Plug the 1/4-inch TRS Plug into the BAL Input of the radio.
In SmartSDR, Select "BAL" for the Radio's Microphone Input.
PTT: You will need to provide your own Foot-Switch or Thumb-Switch for PTT. Connect that to the RCA PTT Jack on the back of the radio.
Connecting to the Balanced Input on 6500 / 6700 Radios:
The 6500 and 6700 radios have a "Dual-Purpose" Balanced Jack that accepts either a XLR Male or a 1/4 inch TRS Plug.
You can use either a XLR to 1/4 inch TRS BALANCED Cable
or
You can use a standard professional XLR Female to XLR Male cable.
Connect the Mic Cable to the Balanced Jack on the back of the radio.
In SmartSDR, Select "BAL" for the Radio's Microphone Input.
PTT: You will need to provide your own Foot-Switch or Thumb-Switch for PTT. Connect that to the RCA PTT Jack on the back of the radio.
What If Your Microphone uses a 4-Pin XLR Connector?
There are some microphones produced by popular companies that use a 4-Pin XLR connector on the mic, and use one of the four pins for a PTT Button on the Mic. You will most likely need to wire your own adapter cable for these mics. Obtain the Pin-out from the Microphone Manufacturer and wire the PTT Pin to the Center Pin of an RCA Connector. Wire the other three to the 1/8 or 1/4 inch TRS Plug as indicated above.
Using Professional "Condenser" Mics:
Professional Condenser Mics require a special 48 Volt "Phantom" power to be provided on the Mic Cable.
The FlexRadio does not provide this voltage on the BAL Line.
This is very different from the 3.3 Volt to 5 Volt "BIAS" that is provided on the 1/8 inch MIC connector to bias "Electret" mics like the FHM-3 handmic and many electret headset / computer mics.
If you wish to use one of these Professional Condenser Mics, you will need to use an external "Phantom Power" injection boxes or an external mixer that has Phantom Power available for this purpose.
Adjusting your Mic for Best Audio:
This article contains a lot of suggestions and links to other resources that will help you get the best possible audio from your microphone and FlexRadio.
Adjusting your Microphone Settings for Best TX Audio – FlexRadio
Using a quality microphone, properly configured, can provide your station with excellent, clear, articulate audio.