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Chris Durfy

Overview/Review of the Lectrosonics Duet IEM System

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I've spent the last few months putting Lectrosonics's latest IEM/IFB system, called the Duet, through the paces here on my current show. The system is hands-down the BEST sounding in-ear monitor I've ever come across. It has a very good range in our studio and is nearly impervious to an incredible amount of wireless signals that are being used on our set.

It is fully digital, scalable and it's also one of the most configurable and flexible cart-based systems on the market.

The M2T Transmitter:

The transmitter is 1RU tall and the width is ½ of a rack. Each transmitter comes with a hardware kit that covers half of what is needed to rack mount two units together as 1RU. There is also a kit available for mounting one M2T in a single rack-space. It boasts a large screen with easy to read, logically laid out status information. It has four levels of brightness control.

In addition, the front panel layout has a headphone jack & volume control, Menu/Select & Back buttons, factory reset button, four channel buttons, menu navigation up/down buttons, USB Port, IR Port and power switch. The USB port is for updates and connectivity to Wireless Designer. The IR Port is for transferring settings to the M2R Receiver (including frequency, name, limiter, mix mode, etc).There are also plugs that can be easily removed to have external antennas front mounted on either side of the front panel if mounting a single M2T with the optional rack kit.


The rear panel has two antenna output BNC connectors, power jack, dual Dante ports, four XLR/TRS inputs and an ethernet port for use with Wireless Designer.


The transmission system is fully digital, and not a hybrid like some other Lectrosonics products. It has two separate transmitter carriers that each contain two audio signals. I'll talk more about the advantages later in the review.


In addition to the four different analog inputs, the M2T features full Dante Connectivity – which means if you are running Dante, you can easily route ANY channel to the transmitter using Dante Controller via your computer.


The menu system is logically laid out. You can adjust the Audio Level/Trim, Audio Input > XLR1-4 and Digital (Dante), Polarity, Custom Headphone monitoring setups, Brightness, Panel Lock, and editing of the names for tracks, signals and the individual M2R's name.


With the Duet System, you can also set up a “FlexList” for creating up to 16 user profiles to quickly access your personal mixes on any of the receivers.


The Duet system is wide-band and runs 470-608 Mhz for the US version, and 470-614 MHz for the export version. Both versions of the transmitter offer RF power output settings at 10, 25 or 50 mW.

The M2R Receiver:

The M2R is enclosed in a very solid milled aluminum case with the Lectrosonics “EbNi” finish - just like the current LT & SM series.

The front of the M2R has a easy to read, square 1” x 1” screen. By default, it shows Name, signal strength & antenna diversity status, battery level percentage and audio levels (L & R). Under the screen there are four buttons: Menu/Select, Back, Up and Down. To the left of the screen is a battery LED showing battery strength (Green, Yellow & Red). This is useful when the screen backlight is set up to sleep after 30 seconds.


The top of the unit has two fixed antennas, on/off & volume control pot, IR port, headphone jack and RF Link status LED.

The left side has the battery door (dual AA). The right side has a USB port. There is a socket on the left and right side for mounting the wire belt clip.


The rear has the model number / serial number plate and the battery installation guide.


The M2R menu system is feature rich, especially compared to most currently used systems on sets. From the menu, you can do Frequency Scans, access FlexLists, Frequency, L/R Balance adjustment, Mixer Mode (choosing a given audio output to L/R/Mono), Limiter functions, HF Boost, Meter Mode, Clear Scan Data, Backlight Level, Battery Type, Lock Settings and set the Compatibility Mode (Duet Digital or FM IFB).

Range / RF Immunity:

The Duet system is limited to a 50mw transmission. Even so, we get a range that easily covers our entire large studio floor. This is considering that the amount of other wireless devices on our set is more than I've ever seen - by a large factor.


In fact, we're using a Clearcom Freespeak II system that sends up to 32 channels of audio out to the comms systems of our puppeteers. We tried the most common forms of IEM/IFB being used (Lectrosonics R1As, Comtek 216s and Sennheiser G3s) next to the Freespeak II transmitters. In each case the receiver got a nasty proximity buzzing sound... all except for the M2R, which was ROCK SOLID right up against the Freespeak II transmitter.

Battery Life:

Using Eneloop Pro rechargeable batteries, we easily made it to lunch (6+ hours), especially with the backlight set to 30 seconds on before going to sleep.


(Update) I’ve gotten reports from another crew who are using the Duet System with Energizer AA Lithiums. They’ve been getting a full day on one set of batteries.


Advantages in the real world:


The Duet system is ideal for use as a PL and IFB for Boom Operators. A BoomOp has the independent ability to switch between Program Mix and Boom ISO Mix using the Mixer or Flexlist menu.


The system is also ideal for directors and executives. Keep in mind, the menu controls can be locked in the menu.

How We've Been Using It:

We've been using it two ways on our set:


1: BoomOp IFB/PL - Our Boom Operators can switch between a Program Mix/Private Line Feed and an Isolated Boom Feed/Private Line Feed at a couple of button presses. The ability to use an isolated feed is great for finding noises and checking for strange reflections / phase issues.


2: Director's Comms / PL to Puppeteers - Our director is also operating a steadicam. We have a belt worn Comm/PL kit that consists of a M2R receiving a custom mix (Program + Performers). We are using a Lectro SMV with a Lectro Mute Switch (Referee-style) and lavalier so the director can then give instructions directly into the comm system to our puppeteers.

Costs (MSRP):

  • M2TND (no Dante): $2150.00 US
  • M2T (With Dante):   $2335.00 US
  • M2R:                        $1080.00 US

Take note:

Only a cart-based transmitter is available currently. There is a plan for a bag transmitter in the near future, but no definitive date set.

We've had the blue volume control knob come loose over time. No worries, just keep a 0.5mm hex wrench on hand and give it a good tighten now and then.

Be warned: once you've given the M2R to your director to listen to, they will never want to listen to another “inferior” IEM/IFB again. ;-)

In Conclusion:

The Duet is a powerful system offering crystal clear audio, great range and high RF immunity. Along with it's amazing routing options and also coupled with full  Dante connectivity, the Lectrosonics Duet IEM Monitoring System is a prime choice for on set use.


Lectrosonics Duet System Page


DUET Manuals:



Full Review and Pictures on my blog:



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Great review Chris, of a great product. I tried a unit at Everything Audio a few months ago - it was clearly the best of the crop, even in a swift demo. sb

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Seems like a great system, thanks for the review. Chris, can you elaborate on the “FM IFB compatibility mode” it is very glossed over in the manual. I had not heard about this feature, I’m assuming that means you could use the receiver with any Lectro transmitter in IFB mode or a T4. Obviously without any of the digital benefits. But still, you’d have a better RF front end, better headphone amp (with limiter) and display compared to an R1a. 


Lectro, when is the M2R 400 mode compatibility update coming?? 


Also, when are the digital SMs coming? I’m assuming some time shortly after I buy SMWBs. 


Ha ha. Kind of. 


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Derek, thanks for your questions. The IFB mode operates basically as you describe: it works very much like an R1a but with diversity and a better headphone amp. We don't have a lot of user feedback on that feature yet, but in our tests here, it walks fairly similarly to an R1a. Sound is about the same, limited by the transmitter audio processing/companding and the narrow FM deviation.


With the current M2R hardware, it doesn't have the resources to do a 400 Hybrid mode - takes too much processing. 


No comment on digital SMs. Our standard answer to such questions is: if we were to design a digital SM transmitter series, what features are most important to you?

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Thanks for your comments Karl. 


What would I want in a digital SM? Really just more of the same, but with better RF characteristics. Wireless remote control would also be a good thing to shoot for. 

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Good review Chris. Corresponds to my experience using the Duet for the last few months. I'll add that I use lithium AA's in my receivers and get a full day plus out of them. 


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On 1/23/2018 at 3:04 AM, Chris Durfy said:

We've had the blue volume control knob come loose over time. No worries, just keep a 0.5mm hex wrench on hand and give it a good tighten now and then.

We are going to a two set screw volume knob on future M2R's in place of the current single set screw. We mill the volume control knob out of aluminum. The mill doesn't care if it has to spend 5 seconds more tapping in a second hole at 120 degrees from the first one. A second set screw causes the knob to have three contact points on the control shaft; the two set screws plus the side opposite  the set screws. This three contact setup is a dozen times more stable than a single set screw  since tripods don't wobble. If you have one of the single set screw units, I'm sure Lectro will send you a replacement knob at NC. You all have better things to do than re-tighten set screws. 

Best Regards,

Larry Fisher


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3 hours ago, Chris Durfy said:

Good stuff Larry! Thanks!

Thank you, for the in depth review.


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