Review: Shure TwinPlex TL46 and TH53

Subminiature, Dual-Diaphragm Condenser Headset and Lavalier Microphones

Despite their small size, lavalier microphones are used in some pretty big spots. News reporting, interviews and film, television and theatrical productions are all applications that require a unique combination of intelligibility, rejection of unwanted sound, robust construction, unobtrusive size and resistance to moisture. Shure’s TwinPlex line of subminiature condenser microphones are designed to address all of these issues and then some.

Comprising four lavalier and one headset model, the TwinPlex line of mics was a “from-the-ground-up” project for Shure. The mics are built in a dedicated facility using a combination of automation and hand-crafted construction, with many of the manufacturing steps developed specifically for TwinPlex technology. The result is a range of subminiature microphones that maximize capsule surface area while reducing size and providing exceptional audio performance.

Sbure Twinplex

At the heart of all TwinPlex microphones is Shure’s patent-pending TwinPlex omnidirectional capsule, which employs dual-diaphragm construction with independent backplates for each. The diaphragms are arranged parallel in a side-address configuration, as opposed to the more typical single-diaphragm, end-address configuration. This essentially doubles the diaphragm surface area within the same amount of space and is said to yield improved low-frequency response, consistent off-axis response and lower self-noise. Overall length of the capsule has been reduced to 5mm by locating the electronics PCB in between the two diaphragms. Very clever.

The TwinPlex line consists of the TL45, TL46, TL47 and TL48 lavaliers (which offer a variety of sensitivity and response curves), and the TH53 headset. Shure sent Mix the TL46 lavalier in black and a TH53 headset in tan. Both mics can be ordered with a choice of connector, including LEMO, Microdot and TA4; we requested TA4 connectors so that we could use the mics with the Shure Axient Digital wireless system (AD1 bodypack). Each mic is packaged in a semi-hardshell case with a variety of accessories, including extra caps (flat and presence), windscreens and tie and vampire clips (T46 only).

The first thing I noticed about the TwinPlex mics was the cable: it’s very pliable and thin (1.6 mm diameter), yet does not feel flimsy. Shure engineers took a great deal of care in developing this medical-grade cable, employing dual redundant grounds for secondary shielding and cable longevity. The cable is said to have no memory effect, and the paintable jacket resists drying or cracking while remaining extremely flexible. Shure labs actually have cable flex machines designed to break cable, and TwinPlex cable reportedly lasts 100 times longer under duress than any cable they’ve ever tested.

TwinPlex mics are furnished with two different removable plastic capsule caps: there’s a flat frequency response cap and a presence peak cap. Initially, I couldn’t tell the difference between the caps by looking at them, but closer examination revealed that the vents on the flat cap are longer than those on the presence cap.

In addition to their effect on the frequency response, the caps serve another important function: they have a hydrophobic coating that repels sweat and moisture, providing longer “sweat out” time (sweat resistance) than an uncoated cap. That might not sound like a big deal, but when you consider the fact that theater performers are under hot lights, and that subminiature mics are often concealed in clothing or hair, it becomes apparent why resistance to moisture is crucial. Shure actually developed a sweat ‘bot to test and improve capsule performance under simulated sweat drip conditions; the research enabled the company to extend the sweat out performance of the TwinPlex mics tenfold.

TL46 Lavalier Mic

The TL46 was designed for high-sensitivity and medium-SPL applications (the TL45 is available for low-sensitivity, high-SPL applications). I used the TL46 with the Axient Digital system for speech reproduction, and, after a bit of tweaking of the mic position, the results were excellent.

Initially, I used the supplied tie clip to place the mic on the lapel of the speaker’s shirt, a few inches under his chin. This placement sounded a bit muffled, even with the presence cap installed. Moving the mic down a few inches to the button placket made a big difference in clarity, and his voice sounded natural and clear. Rejection of off-axis sound was generally very good, though we did experience a bit of feedback when he turned and faced the speakers (good grief).

I preferred to use the mic without the windscreen because it’s visually less obtrusive, but I noticed that if the talent spoke while looking down in the direction of the mic he could occasionally produce a plosive sound. The windscreen cured this, and truth be told, the mic is so small that it disappeared on his shirt even with the windscreen installed (it was a black mic on a dark blue shirt). When the talent moved his head—which he did often—I could detect no difference in timbre from the TL46.

I next used the TL46 to record audio for a video on drum tuning, using both the Axient Digital wireless system and a custom-built preamp that enabled me to connect both TwinPlex mics via wire into an external mic preamp (a Grace 201). Dynamic range of this recording was huge because you have a person speaking in a conversational voice, and then the sound of a snare drum being whacked, both being captured by a mic that’s about 18 inches away from the drum. The TL46 handled it effortlessly, as did the TH53 headset. Background noise was never an issue, and the mics handled the SPL from the drum without distortion.

TH53 Headset Mic

I used the TH53 in similar applications, including the drum tuning video. The TH53 seemed to capture a bit less of the room ambience than did the TL46, which enhanced the clarity of the vocal while keeping the snare sound focused.

When I first saw the TH53’s headset, I thought it looked delicate and had my doubts that it would stay put; but once set in position, it did not move at all. The headset has separate adjustments for headband width, ear hook angle and boom angle. A pivoting clutch with an easy-to-grab thumbwheel sits behind the ear and is used to adjust boom height and boom arm length. Once this is tightened—you don’t have to use much force—it remains in place. There’s a clutch on both sides of the headset so you can mount the boom on either side. Some folks may feel the clutch knobs are a bit on the large side (about a half-inch in diameter), but I did not.

Provided that I placed the headset as suggested in the manual, I never heard a plosive sound, nor did I experience any issues with “t” or “s” sounds. The headset has wonderful fidelity and seemed to produce a more extended low-frequency response than that of the TL46. Using the presence cap on either model produced a very subtle difference, more adding a sense of air or space as opposed to creating a pronounced peak in the response. I thought I might have heard a bit more emphasis on “s” or “t” sounds with the presence cap. The caps don’t require a lot of pressure to pull off or push on, yet remain in place securely.

Shure’s efforts regarding the TwinPlex cable have paid off: I never heard any noise generated by clothing rubbing or rustling against the cables, or even when handling the cables. The flexibility of the cable along with the supplied accessory clips made easy work of dressing the cable through clothing without it being annoying.

I found that the SH53 and TL46 produced excellent-sounding vocals, though I think I’d prefer the extended LF response of the TH53 for theater applications where the talent would be singing as well as speaking.

As you would hope for a lav or head-worn mic, the capsules are small enough to be hidden easily in clothing or hair, yet produce a full frequency response. Capsule self-noise was never evident in quiet applications, and both microphones demonstrated the ability to handle a wide dynamic range. At one point I even gave the TL46 a spray or two with water, and it didn’t seem to affect the operation or produce any audible noises.

The TwinPlex performance, combined with excellent sound, robust construction and resistance to moisture, add up to a line of microphones that will undoubtedly have a formidable presence in theater, film and TV applications. 

Product Summary

Company: Shure

Product Name: TL46 Lavalier and TH53 Headset Subminiature Microphones


Price: TL46: $399; TH53: $599 (prices vary depending upon connector)

Pros: Great intelligibility; extremely low handling noise; available in a variety of colors, including black, cocoa, tan (TL46 also available in white); headset is very stable

Cons: Difficult to identify various caps