22 resolution September 2017

We looked at the ground-breaking Schertler Arthur modular mixer in Resolution V15.7 October 2016, but the Swiss company’s reputation was originally

built on Stephan Schertler’s quest in the early 1980s to improve on the typically nasal-sounding piezo pickups used for amplifying stringed instruments. Schertler is a double bass player so the motivation was obvious. He developed the STAT Series of contact microphones. There are variants of these for different instruments: double bass, cello, violin/viola and gypsy guitar. And these are available in bundles with different preamps. Requiring 10V “phantom” power supplied on an unbalanced cable, there are three possible options: the basic STAT Pre powered by 9V battery, the two channel YELLOW Single, and the one supplied in this package, the three channel YELLOW Blender.

The bundle comes in a fabric zipped holdall. Inside are two sections: in the larger part is the YELLOW (blue coloured) “Acoustic Class A Blender” — the preamp unit. In the smaller sections is a PSU for that, the contact microphone with a short cable to the clip and phono socket. Also in the larger section is a cable to run to the preamp, the paperwork, and a nice blue retractable ballpoint pen labelled with the Schertler website link and the motto “this colour is YELLOW”.

I bought an electric Yamaha Silent Cello for live use on noisy stages in order to hear myself without feedback, so was interested to try this with my acoustic cello. The first job is to grind the cork “stopper” mounted onto the contact mic to the correct curve to fit in the near-circular gap in the bridge underneath the top (A) string of the cello. There are all kinds of shapes of blanks for bridges, which are then fettled to taste by a luthier for a particular cello. My two cellos have vastly different sized holes in their bridges, so naturally I shaped this to fit the larger hole which happened to be on the better cello. However, for gigging I might be more tempted to take the slightly more battered instrument! I squidged it in and left it as a fairly tight fit — you wouldn’t want it to fall out mid-gig, but it’s tricky to judge how much pressure you should force on mic cork or bridge. Having said that, this is all vastly quicker, simpler and less potentially problematic on a valuable instrument than

any pickups that mount under the bridge feet. The gold plated phono is attached to a half-moon shaped sprung clip designed to attach to the tailpiece — this fitted well to my cello. Inserting the (also gold-plated) plug on the fancy braided lead is a bit tricky as it is a tight fit, but again, you don’t want things pinging off mid-set, and a quarter-inch jack plug/socket arrangement would be bulkier. At the other end of the cable, an angled jack plug goes into the YELLOW Acoustic Class A Blender II. This is the top-end luxury preamp option, with a Mic channel, Instrument channel, a Send on both channels and a third Return input. About the size of a VHS tape (if you remember those) the Mic XLR, Instrument jack and Return jack inputs, Send and minijack headphone outputs are mounted at one end, with PSU input (a little blue LED comes on adjacent when power is fed in), DI (-20dB) and Master Balanced XLR and Unbalanced jack outputs at the other end. With four rubber feet this can be placed anywhere convenient. The PSU is a transformer plug (an annoying 2-pin Euro shaver type) with flying lead to a fairly large DC barrel plug. To use the pickup, you need to press the +10V button which sends phantom power to activate the contact mic. Next to this button is a Warm button which is a low pass filter, and a -12dB pad. There is a Gain knob, and four fixed-frequency sweep EQ bands. A high pass filter is also provided (120Hz), and there is a Send knob and a Volume fader, before the signal joins the Mic channel and Return at the Master Volume knob.

Plugging the balanced output into my audio interface I found that with Gain and Volume on the channel and the Master Volume output all to be cranked up fairly high, there was impressively enough level for a Line input rather than Mic. But there was a fairly high level of background noise coming from the mic. Not intolerable, but louder than I expected. Turning up my monitors, the sound was big and warm, if a tiny bit fuzzy. After consulting with Schertler, it seemed that my installation was incorrect as the mic was touching the bridge wing and needed rotating. On doing this, things improved with more signal to noise and a better defined high end. However, I discovered that rotating it too far away from the wing things went

thinner and quieter. So it seems positioning is super-critical, and experimentation is required. Edging the monitor level higher, I was astonished at the lack of any hint of feedback. At maximum volume, the A string would start to vibrate and feed back, but this was soon stopped by touching it, and I simply couldn’t get anything nasty, howling or boomy to happen. With a touch of reverb, the sound was inspiring, and it’s exciting to think I could use my main instrument onstage without fear of feedback. The Warm filter might be handy for mellower tones. And some useful shaping could be achieved with the EQ. The high pass filter seemed a touch too drastic up at 120Hz and might have been better at say 75Hz, but the Low EQ band is a 60Hz shelf so you can roll off some very low end there. The other frequencies are nicely chosen — 300Hz peaking for body, 1.3kHz peak for nasal or mid punch, and 12kHz shelf for some sheen.

Plumbing in my Yamaha Silent Cello for comparison, the dedicated electric instrument’s output was generally more nasal and somewhat bass-light. I find that rolling off the high end and boosting the low end of the Yamaha’s output helps me hear my tuning better when using in-ear monitors. The STAT contact mic’s warmth and rounded yet open tone is certainly more desirable.

The Return is a useful extra input, handy for injecting an effect or any line source back in. I was slightly disappointed it was mono (balanced), because stereo would have been better for use as an auxiliary onstage monitor input to balance other sources with the cello.

Overall this is probably the best solution on the market for live cello amplification, and I’m sure the same goes for the Schertler’s instrument versions of the STAT. If you’re on a budget and want to be free of mains hook-up, I’m sure the STAT Pre will serve you well, but the YELLOW preamp is superb. n

ContactSCHERTLER GROUP, SWITZERLANDWeb: www.schertler.com

PROS Incredible lack of feedback, much warmer and more natural sound compared to piezo pickups, great preamp with useful EQ.

Installation position critical, some background noise, Euro shaver plug, mono Return input.

CONS

REVIEW

Schertler Stat-C RoadProducer, engineer — and cellist — GEORGE SHILLING tests an innovative contact microphone.