Lectrosonics Quadra (IEM) Wireless review

February 11, 2011 at 1:55 pm

Lectrosonics Quadra

Lectrosonics Quadra M4T Transmitter Pricing InformationLectrosonics M4R Receiver Pricing Information

Everyone loves a home run, and it looks like Lectro just knocked one out of the park with the new Quadra.

The Quadra by Lectrosonics is a digital, wireless, personal headphone monitor system capable of four discrete audio channels with a single transmitter and bodypack receiver. It delivers the range, fidelity, and build quality that Lectro is famous for.

With a transmitting power of 200mW, the Quadra uses a relatively vacant, no license required frequency band of 902mHz – 928mHz, allowing eight operating frequencies to choose from when in 2-channel mode, and four frequencies to choose from when in 4-channel mode. Doing the math reveals that up to eight transmitters can be used together (4 when in 4-channel mode, or 8 when in 2-channel mode), making it possible to send up to 16 discrete audio channels in a single location.

In Concert

Designed primarily with live music performance in mind as an IEM (in-ear monitor), the Quadra’s four channels give a performer the ability to adjust their own headphone mix with the 4-channel, custom-configurable, digital mixer in each compact receiver. During a stage performance a typical scenario might be to have a stereo mix on channels 1 and 2, with a performer’s voice on 3, and their guitar on 4. The performer has the ability to create and adjust their own personal balance of those channels to their liking. There is nothing else like this for the music industry. They’re going to love it.

There’s a lot to discuss about the operation and technical specs of the Quadra, which I’ll get into later in this article, but first…

On the Set

In a niche where ingenuity is required for success, film and video production sound professionals are in the habit of checking out cool gear not made for them and coming up with uses that may not have occurred to the manufacturer. It didn’t take me long with the Quadra to realize there are some very useful and unique applications for the Quadra on a film production set.

More and more production sound crews are relying on wireless boom mic rigs, which requires the boom operator to monitor with a wireless receiver. While the quality of traditional wireless monitors (those in the 72mHz and 216mHz band) is barely adequate for boom operators, the first plus for the Quadra is that its sound quality is nearly indistinguishable from a hardwired headphone connection. But an even more compelling reason for the Quadra on the film set is the same as it is on the concert stage–the ability for the person wearing it to control their own mix. For example, it is common for a boom operator to request that the sound mixer (their boss) change their headphone signal from a mono mix to only their boom mic, or maybe have both split to each ear, then back to mono mix, etc. Not only can this can tax the abilities of a portable mixer, it can also distract the focus of their boss. With only two channels of the Quadra, all three of these mix options (mix on ch-1 & boom prefader on ch-2; mixed and routed as desired) can happen at the discretion of the boom op, without bothering their boss. But wait, there are two more channels…

When a second boom operator enters the scene (which is becoming more and more common), things get more complex. The second boom op needs to be able to hear the same mono mix as the first boom op, but with the option of also hearing only their own boom mic. It is a simple matter to send the second boom signal to the third channel of the Quadra transmitter. Now the two boom operators can each listen to their choice of the mono mix, or their own mic, but also listen to each other’s mic, split (or not) in both ears however and whenever they like. Since each boom op can now listen to the other’s mic, prefader, when the mixer pulls their faders down they can also talk privately to each other to work out the upcoming scene. But wait, there’s still one more channel…

The above scenario uses just three channels (mix, boom 1, and boom 2), leaving the Quadra’s fourth channel up for grabs. Imagine that the director, script supervisor, producer, and other lucky people are using Quadra receivers for their on-set wireless monitoring. Now consider using the fourth channel as the “entertainment channel”, such as internet radio (Pandora), iTunes, the Laker’s final playoff game, etc., plugged directly into the fourth input of the Quadra transmitter. This channel could be brought in or out by the listener, whenever they want, without the danger of it going through the recording equipment. In this scenario, the director’s receiver could be configured to control the program volume with one knob, and the Laker’s game with the other. Don’t get it yet? A lot of people didn’t get Facebook at first.

The real world

From my walk tests using the supplied whip antenna on the transmitter, I can’t imagine a stage or auditorium interior too large for the range of the Quadra when using a relatively clear channel (they were all clear for me in downtown Los Angeles). But on a stage it’s easy; there is usually direct line of sight between the transmitter and receiver…

Let’s see a show of hands of everyone who’s worked on one floor, sweating it out with wireless because the camera and actors are on another floor. That’s what I thought…100%. So I did a test that may seem odd except to those who actually work in production. In a downtown concrete and steel high-rise building, while listening, in stereo, to a recording of the Berlin Philharmonic performing Beethoven’s 5th Symphony, I walked away from the transmitter, past a metal door, 25 feet down the hall to the elevator, and went down one floor at a time. I was able to go down five floors before experiencing a drop out. In this environment, just like in my line-of-site tests, the range of the Quadra was equal to or better than other established professional wireless monitoring systems in similar situations. By the way, even with the Quadra five floors down, Beethoven sounded exactly the same as when my phones were plugged directly into the player.

Digital latency: ultra low

All digital processing has a degree of “latency” (i.e. the lag time between input and output). Singers cannot tolerate any noticeable lag between their singing voice and what they hear in their monitors. Likewise, boom operators are similarly disturbed by lag in their headphones. With this in mind, Lectrosonics developed a system with ultra-low latency of less than 0.5ms (equal to about 6 inches of sound travel), which reduces it to a non-factor in this application.

Marketing latency: ultra low

The Quadra was shown for first time at the Los Angeles NAMM show in January, 2011, in finished, fully functional form. With that act, Lectrosonics joins an exclusive rank of manufactures who understand the need to reduce what I call “marketing latency” – the lag time between a product’s introduction and when it actually exists. The Quadra is brand new, with evaluation units tested, refined, and available, and the first production shipments for sale are promised mid-March. Yet it has the look, feel, and function of an established product, refined and debugged. Even the included operating manual is well laid out and color printed on high quality paper. So kudos to Lectrosonics for taking the needed time to develop the Quadra quietly, resisting the temptation of a premature introduction, waiting until it was ready.

Complete list of needed tweaks

1) The indicator lights are too bright. Since these receivers will normally be used in dark stages and sets, the ultra bright LEDs will be a common complaint, too often fixed with black tape. If a menu option to vary the brightness is too much to hope for, then I’d suggest turning them down a few clicks at the factory. [NOTE: Feb 14, 2011--Done. See Lectrosonics' Karl Winkler's reply below]

2) DC power option. While the internal 120VAC-240VAC mains only power supply is fine for stage shows, a 12VDC power option would go a long way for the location sound folks. [NOTE: Feb 14, 2011--It is now my understanding that Lectrosonics is writing Quadra-style menu options for the 12V powered D4 transmitter, which, essentially, satisfies this request.]

3) This space intentionally left blank.

New product confidence

Any reticence about the Quadra being a new product should be offset by the fact that it is largely based on the Lectrosonics D4–the four channel digital wireless system designed for TV broadcast and video production as a high quality, multi-channel “camera hop”. The D4 has been out several years, has been nicely refined, and is quite stable. The primary differences with the Quadra are that the transmitter is made to be a half–rackspace (mounting kit available), and the Quadra receiver is a pocket sized monitor/mixer. Also, menu options were written specifically for the Quadra to give it as much monitoring versatility as possible in terms of what the listener hears, how they hear it, and how they control what they hear.

Peanuts and Crackerjacks

You know that sound of a fast moving wooden club smacking into a hard leather-covered ball? I think I just heard it again.

Download the Quadra IEM System Technical Data Sheet (1.61MB PDF)

Download the Quadra IEM System Manual (6.46MB PDF)