Neumann TLM50

Neumann's versatile TLM50 omni‑pattern mic combines transparency with a subtle high‑end lift.

If you've had any experience of Neumann microphones before, you'll know that when Neumann set their minds to something, they do it properly. Not only are their microphones beautifully engineered, but this latest model also comes in a nice hardwood case with a custom‑moulded foam interior and a cable that terminates in a combined XLR and swivel‑mount stand adaptor. A further adaptor is provided, designed to clamp to the mic's own cable and allowing it to be hung from the cable in an auditorium. The full shockmount is an optional extra.

What's unusual about the TLM50 is that it's a fixed‑pattern omni (omni‑directional, picking up sound equally well from all directions) microphone. While omni mics have the most natural, open sound, most people still tend to use cardioid‑pattern mics (which pick up sound best from one direction) to achieve the best possible separation. However, as I've pointed out on many occasions, the difference in spill from off‑axis sources isn't nearly so great as you might imagine, especially in a room with reflective surfaces, so unless you're working in a really difficult situation, an omni mic may well give you noticeably better results.

Design

Styled along the lines of other Neumann studio mics, the TLM50 is a transformerless design (hence the TLM prefix), but the 50 in the model number is a nod in the direction of an older Neumann tube mic that used the same design of capsule. The capsule itself is a medium‑diameter 12mm device flush‑mounted into the surface of a 40mm‑diameter sphere, in order to preserve the best omni response possible across the frequency range. The spherical shape helps eliminate diffraction and offers less of an obstacle to sounds coming from behind the mic.

This is a mic designed to be used on‑axis, where it produces a transparent, open sound that is also solid at the low end.

To achieve a wide frequency response, the diaphragm mass has been kept low by using nickel, 2.25 microns thick, rather than the more usual materials. The diaphragm is manufactured by a galvanic process, which I assume is related to electro‑plating. A dual‑layer mesh basket protects the capsule and helps dissipate breath blasts that might cause popping, but there is no internal foam shield that might affect the high‑frequency response of the microphone. Neumann have created what they term an 'active capsule', in that the impedance‑converting stage is built into the capsule housing, so that the majority of the signal path is low impedance, to prevent hum pickup on the vulnerable high‑impedance section of the circuit.

Though this is a single‑pattern mic, switches are fitted to bring in a 10dB pad and to activate a low‑cut filter that rolls off below 100Hz. In the linear position, an active filter comes in at 30Hz to prevent very low‑frequency sounds from producing sub‑audible signals that might compromise the performance of other equipment later in the signal chain. The pad isn't just a resistive attenuator, but works by reducing the capsule voltage. Because of the very small air gap inside the capsule, changing the voltage alters the acoustic impedance of the capsule slightly, resulting in a marginal top‑end lift.

Power for both the capsule and the amplifier comes from an internal DC‑to‑DC converter, which means that there may be a slight noise when the mic is powered up or down. Likewise, because the pad operates by changing the capsule voltage, the mic may take a few seconds to stabilise once the pad has been switched in or out. Phantom power to the 48V standard is required to operate the microphone, though if standard phantom power isn't available, Neumann produce a battery‑powered phantom supply that may be used with the TLM50.

When Neumann set their minds to something, they do it properly.

Testing Times

In my tests with vocals and instruments, the TLM50 behaved much as I expected, though the off‑axis high‑end loss was a little more pronounced than I had anticipated. This is a mic clearly designed to be used on‑axis, where it produces a transparent, open sound that is also reassuringly solid at the low end. As with all omni mics, you don't get the proximity bass boost that cardioid mics exhibit, but I still found the sound warmed up slightly when the mic was used very close up. The TLM50 is actually a very nice vocal mic, and it makes a nice change from using cardioids all the time, but you do need to work in a room that doesn't have an adverse acoustic character, otherwise some of this will be picked up by the mic. The best vocal sound is achieved by using the mic just a few inches from the mouth, though an additional pop shield is necessary to guarantee freedom from popping on 'plosive' B and P sounds.

Checked out with acoustic guitar, the TLM50 produces a very natural result, partly because the acoustic guitar radiates sound from all parts of its body and neck, and having an omni mic helps render these off‑axis sounds more accurately. The noise level from the TLM50 is reassuringly low, as you'd expect from a mic in this class, and because it can handle high SPLs, applications such as percussion recording and drum overhead work are also easily within this mic's capabilities. Indeed, if you have a reasonably benign room to work in and you want one high‑quality mic that can handle just about any job, this might well be it.