Sunday, March 25, 2012

Sanken CS-1 Short Shotgun -- But Is It A Shotgun??


Sanken CS-1e
The Sanken CS-1, and for that matter the Sanken CS-3, were both modified shortly after they came out. The new versions are the CS-1e and CS-3e. It's been some time, but I recall the modification had to do with lowering the noise figure on each mic.

This is a review of the original Sanken CS-1 I wrote shortly after it came out.  As I get more information from Sanken, I will modify this article.

The Sanken CS-1 short shotgun (now about $850) is aimed at the professional ENG and EFP markets. On the outside, it looks like any other interference tube shotgun mic. Shotguns traditionally have a small capsule at the rear end of an interference tube. Slotted ports down the side interfere with sound entering from the side in a calculated way, allowing sound, especially high frequency sound, to enter only from the front.

Most shotguns are surpisingly more omni directional at mid and low frequencies. This limits their effectiveness in slappy interior spaces and even in exteriors when the mic is on or near a large, flat, hard surface such as a macadam (asphalt) parking lot.

BREAKING THE RULES
The Sanken CS-1 appears to be a short shotgun. It's even called a short shotgun and although it looks like one from the outside, It's not. When I saw the first version of this mic at NAB 2003, I was struck by the fact that there was no opening at the end of the tube. Regardless, when you waved the mic at a source, its pattern of reception behaved very similarly to that of a traditional shotgun. There also appeared to be fewer mids and lows coming in from the side.

When the latest version arrived for this review, an open grille had been added to the front end. I took a peek inside. To my surprise, the usually empty interference tube was completely stuffed with circuit boards and several thin rectangular diaphragms. The phasing of the diaphragms is used to create a supercardioid pattern similar to that of a shotgun.

My own kit includes a Sennheiser MKH416 (mostly for exteriors and acoustically treated soundstages) and a Schoeps CMC641 (for interiors and exteriors when reach is not a factor). The task, then, was to determine what the three mics had in common, and how they differed.

The Sennheiser MKH416 lists for $1,275, the Schoeps CMC641 with clamp and B5 pop filter for $1,180 (1n 2012, about $1800 USD). The Sanken CS-1 lists for $795. That certainly makes it more attractive. At a length of just over seven inches, the Sanken CS-1 is shorter than an MKH416 and a few inches longer than a CMC641. If you're running with a camera mounted shotgun, you may be attracted to the CS-1's shorter tube. The CS-1 and CMC641 each weigh about four ounces, the MKH416 just under six ounces. Only you can decide if carrying two more ounces around all day makes a difference.

My first sound comparisons were done in my studio; a very quiet space with a balance of absorptive and diffusive treatments that result in a tight, but not dead environment. Head on and at very close range (less than a foot) the CS-1 exhibited a slight dip and return in high frequency response as I moved from directly on axis to the edge of the mic's hot spot. At edge of frame closeups of a foot or more, however, the dip is not apparent. The mid and far patterns remain fairly constant at about two feet wide, outside of which, a noticeable roll-off occurs.

The CS-1 had more selfnoise than the MKH416. Not as much as my Countryman EMW lavalier or Sony ECM 88, but still more than the MKH416. The MKH416 is about 2.5 dB more sensitive than the CS-1. When I adjusted my preamps to make both mics equally loud, the selfnoise of the CS-1 was even more apparent.

Some people use the MKH416 as a voiceover mic, working it at a distance of one to three inches. At distances of a foot or less, the MKH416 had more upper bass/lower mid chest tone which made voices sound bigger and closer. At a distance of a foot of more, in my acoustically-controlled space, the width and reach of the patterns and the frequency response of the two mics were similar. Both mics got roomy at about the same distance. At ninety degrees off axis, the CS-1 had much less high frequency response than the
MKH416. Off the back, the CS-1 had more high frequency response than the MKH416.

I'm not a big fan of camera mounted mics. As a sound guy, most of the cameras I've been near are just too noisey for me to even think about mounting a mic. I'm sure there are some relatively quiet cameras out there. I just haven't heard them yet. In this test, the CS-1 didn't do quite as well as the MKH416. Probably because the capsules are mounted along the side of the CS-1 shaft.

The CS-1 also had more selfnoise than the Schoeps CMC641. Up in the acoustic of my relatively average living room, at a working distance of two feet, the CS-1 had more room ring than the CMC641 and even with the Sound Devices 442 mixer adjusted to the first (80 Hz) high pass position, the CMC641 exhibited more low end.

UNHAPPY TOGETHER
I ran into an unusual problem when I fired up my Sound Devices 442 mixer and plugged in the mics. The CS-1 and 442 were not happy together. The mic and/or mixer went into oscillation. I contacted Sound Devices and Plus24, the distributors for Sanken, and was told this was something they were working on and they suggested engaging the high pass filter would solve the problem. It did. Apparently this problem is specific to the 442. The problem never evidenced itself with any other preamp I tried, including an old, noisy Shure FP31. (I believe this was one of the problems addressed and fixed in the Sanken CS-1e.)

In the living room, as a hand-held mic, with a working distance of six inches to a foot, the MKH416 provided more chest tone, less room and slightly less high frequency response. At a distance of two feet the MKH416 sounded a little more focused than the CS-1. At four feet, they were very similar.

HEADING OUT
Outside, in suburban Baltimore County, the differences between the the CS-1 and MKH416 became less noticeable. The distant din of automobiles on I-695 and I-83 covered up most of the selfnoise. Because I knew it was there, and because the frequency of the CS-1 selfnoise was higher in pitch, I could pick it out. In town, I probably wouldn't have been able to hear any selfnoise at all. Beam widths of the two mics were very similar as was their reach.

IN CONCLUSION
I give the Sanken engineering team a lot of credit for coming up with an extremely unique product. They have, in effect, redesigned the shotgun mic. Although I doubt that anyone who owns an MKH416 will stop using it in favor of the CS-1, Sanken will probably pick up support from those who don't have $1,275 to spend on a MKH416, especially if they record in noisy locations like "media circus" press conferences.

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