Shure's SM product range needs no introduction. When someone talks about a 57 or a 58, everybody knows what they mean. Those mics are probably two of the most widely used in history, both in the studio and live. And no wonder, given that they are absolutely reliable, rugged and excellent value for money. Shure also has three other microphone lines: PG, BETA and KSM. These product families are also widely known and, of them all, the KSM includes the manufacturer's most select mics. They are characterized by a finish that is usually silver/gold (champagne), with models such as the KSM44A, KSM42 or KSM32/SL at the top of the line.

The mic at hand, the SM27 model, is the successor to the KSM27 (now discontinued), a microphone that belonged to Shure's premium product range and has been redesigned so it can proudly bear the "SM" badge. It is a one-inch-diaphragm condenser microphone, side-address cardioid, which is meant to offer the strengths of the KSM line while providing the ruggedness expected of an SM.

The model has swapped the silver finish for matte black (to make it easier to use in live applications), and becomes the first large-diaphragm condenser in the legendary product range.

Features
The color change is not the only transformation the 27 has undergone. For the new model, Shure wanted to keep the technical characteristics of the KSM version while improving other aspects in the move to the SM. Compared with the KSM27, the SM27 offers a wider dynamic range (123.5 dB, almost 6 dB more), a higher maximum SPL (148 dB with the pad) and a self-noise of 9.5 dBA, which gives it a signal-to-noise ratio of 84.5 dB (see Table 1 for a comparison of both models).

The SM27's frequency response is initially identical to that of its predecessor (see Figure 1): it has a linear response across the entire spectrum (20 Hz-20 kHz), with three boosts located around 60 Hz, 6 kHz and 12 kHz.

The measurements in Figure 1 correspond to a distance of 60 cm.

During testing it was clear that the mic lets you play comfortably with the proximity effect, since the bass boost naturally increases as you get closer to the mic (remember that the pattern is cardioid), but not in an exaggerated way. Speaking of the pattern, it is the result (see Figure 2) of combining the signal from two Mylar diaphragms, one inch in diameter and 2.5 microns thick. Polarization is done with 48V phantom power, and is made possible by the gold sputtering of the diaphragm.

The electronics are Class A and transformerless, and include a subsonic filter to remove frequencies below 17 Hz.

The mic also has a 15 dB attenuation pad and a three-position high-pass filter, operated by two small switches. The first filter position turns it off, the second is called "cut" and gives -18 dB/octave below 80 Hz, and the third is "Roll-Off," with -6 dB/octave below 115 Hz.

Finish and Accessories
The SM27's finish is black/charcoal gray, and it offers the ruggedness expected of an SM mic. The Shure logo and the cardioid symbol mark the mic's most sensitive side, and at the opposite end are the switches for the pad and high-pass filter.

To make general use of the mic easier, the SM27 has a triple-grille system around the diaphragm, designed to help effectively reduce plosives. Indeed, during testing the system could even save the session if there were no pop filter, though for some more troublesome voices one would still be needed.

Inside the case the mic comes in (Shure's classic heavily padded case), the mic stand mount is also included. It's a metal clip (in the same dark gray color) that attaches to the microphone with a threaded ring and lets you position the SM27 in different positions solidly and comfortably.

It doesn't come with a shock mount, but the manufacturer states that the mic's internal shock-mount system is very effective, and again during testing this proved to be the case. For applications that do need an additional shock-mount system, the A27SM clip is sold separately.

In Action
Part of the testing took place while recording a punk-rock-style song. Initially, the mic was placed as a mono overhead on the drums, centered over the kit about 90 cm away. The treble boost in the frequency response was immediately noticeable. Because the style of the song called for rough drumming with lots of cymbals, the SM27's boost made them sound somewhat harsh in the solid-state position of the preamp. The SM27 had been connected to a Universal Audio 4-710, which has a solid-state and tube position on each of its four channels, as well as a compressor inspired by the legendary 1176. When switching to tube mode and "pushing" the preamp a bit harder, the apparent harshness of the cymbals disappeared, giving way to a warmer sound that was still well detailed and balanced in lows and highs.

The next step was to try the mic at the front of the kit, as a mono room mic. Again, the boost seemed a bit harsh, but switching to the tube preamp gave a balanced, clear and defined room sound. That particular frequency response means the SM27 can also be used as a single (outside) kick drum mic, since it provides a round sound with attack.

When recording electric guitars, the mic didn't stand out especially, again because the already harsh guitars needed a different type of mic (in the end a combination of dynamic and ribbon was used). However, the SM27 could very well be a great fit for clean guitar sounds, placed somewhat away from the cone to capture a blend of room and amp.

Where this microphone stood out again was on the vocal take, since the treble boost, combined with a marked but not exaggerated proximity effect, gave the provocative character the voice needed on this song.

As for the mechanical features, throughout all the tests it was clear that the internal shock-mount system did its job perfectly. For its part, the clip let you lock the mic firmly in different positions without too much fuss, which is always appreciated. The pad proved useful in some of the tests, and the high-pass filter option in two different positions is a detail that lets you tailor the mic's response well to different situations.

Conclusions
The SM27 earns the right to carry the SM initials. You only have to pick it up to feel the solidity it conveys, without a doubt one of the characteristics that define this product line. Solid in terms of finish, but also in terms of sound, handling and accessories. The switches operate quietly, and the clip that comes with the mic lets you position it and forget about it.

One thing missing is the ability to switch the cardioid polar pattern to omni / figure-eight, which would expand the mic's possibilities. It seems that option is reserved for the higher product lines.

The frequency response is flat, and the treble boosts it provides give what is sometimes called "transparency" to the mic, though on certain occasions it can result in a slightly harsh sound. Nothing that can't be fixed by pairing the mic with the right preamp, but it has to be kept in mind if you want to buy an all-purpose mic, since in some applications the SM27's character may not be the most suitable. What I mean is that it may not be the best mic if you want to buy your first and only large-diaphragm condenser for your studio for the time being, but it is without a doubt a very valuable tool to reach for to provide certain colors immediately. In that sense, if you have other mics in the drawer, adding an SM27 to the arsenal is highly advisable.

Thought of from a live perspective, the microphone is rugged, and the aforementioned character can be a great help in those situations. If you also work both live and in the studio, the SM27 seems ideal, since it will certainly let you operate comfortably in both fields.

In short, a great mic (as could not be otherwise coming from Shure) that perhaps lacks the versatility of others in terms of character, but that on the other hand can double up in studio and live applications thanks to its ruggedness, options and good sound.

Technical Specifications
Polar pattern
Cardioid
Impedance
150 Ohms
Sensitivity (1 kHz, open circuit)
-37 dBV/Pa (1 Pascal = 94 dB SPL)
Maximum SPL (1 kHz at 1% THD)
1000 Ohm load: 133 dB (147 dB, Pad on)
2500 Ohm load: 138 dB (152 dB, Pad on)
Signal-to-noise ratio (referenced to 94 dB SPL at 1 kHz)
84.5 dB
Dynamic range (1 kHz)
1000 Ohm load: 123 dB
2500 Ohm load: 128 dB
Common Mode Rejection (20 Hz - 20 kHz)
> 50 dB
Clipping Level (20Hz-20 kHz at 1% THD)
1000 Ohm load: 1 dBV
2500 Ohm load: 7 dBV
Self-noise (typical, equivalent SPL, A-weighted)
9.5 dB
Net weight
642 g
Switch
Attenuator: -15 dB
Three-position high-pass: flat, -6 dB/octave below 115 Hz or -18 dB/octave below 80 Hz.
Power
48 Vdc phantom, 5.4 mA