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October 1988

by Paul Crowther

NZM Is 30 Years To The Good! #2 – Sound Check

by Paul Crowther

NZM Is 30 Years To The Good! #2 – Sound Check

The second published New Zealand Musician issue (with an orange-suited Dave Dobbyn gracing the cover in recognition of the release of his ‘Loyal’ album) was published back in October 1988 – 30 years ago!

Aside from a 12-year DD career highlights package that included some well interesting facts (like that among his first jobs were pumping gas and selling paintings door-to-door!) the 32-page October 1988 issue included reviews of the headless Steinberger TransTrem guitar alongside Maton’s M-325 acoustic, a profile of Rotorua’s Metro Music (which coincidentally closed its doors for the final time just this month), an interview with the perennial Rodger Fox and the first column of a series entitled Sound Check, written by Paul Crowther.

What a coup! Over the three decades since Paul has come to be regarded as right up there among this country’s finest live sound engineers and, of course, gained considerable international acclaim as the brains behind the famed Hot Cake guitar distortion pedal. He’s a legend.

In a follow up to the premiere Zen Guitar article repeated from NZM’s first ever issue, we very proudly present the first Paul Crowther Sound Check column, as a memorial to the magazine’s second issue. Thanks all for 30 years of fond Kiwi music memories, successes and achievements.
Richard Thorne – Publisher

Through this column I hope to help musicians, sound people etc. with various technical and not-so-technical aspects of their instruments and associated electronic equipment, both by relating various problems that I have experienced, or heard about your sound system, keyboard set up, or whatever. If I can’t help, no doubt I can ask someone who can. Remember that if you’re having trouble with something, then no doubt other people are having a similar problem.

I would like to start the ball rolling by telling you about a rather interesting problem we had on the recent Koko Taylor tour. We supplied the sound system for the North Island gigs, and I was looking after the front-of-house mix. Everything had been going fine until we got to the Baycourt Theatre in Tauranga. We set up the equipment as usual and had the PA and foldback going, but when Koko’s band The Blues Machine arrived for soundcheck and plugged in their guitars, which they preferred to carry with them, our problems started!

As soon as an amp was turned up a little way, this rather strange, whistle-like, high-pitched feedback would occur. Well, I can tell you, we tried everything we could think of to fix the trouble. Both the lead and bass guitars were affected, but not Eddie King’s guitar, which interestingly had humbucking pickups.

Darren Watson, the singer-guitarist with support act Chicago Smoke Shop had real hassles. His guitar was feeding back with hardly any volume at all! The poor bloke was beside himself. Dale, the technician from the theatre, couldn’t suggest any reason for the feedback either. Note that switching off the main PA and foldback system made little difference. All we needed was a guitar plugged into its amp, turn it up a bit, and “Squeeeeeeeeeee … !”

Mystified, we went for what was left of our tea break. As they say, the show must go on, and so it did, complete with the occasional burst of high-pitched feedback. In spite of this everyone seemed to enjoy the concert. Koko’s bass player had the most problems, and he was using a very trebly amp setting, which didn’t help either. I managed to alleviate the problem slightly by cutting some hi-mid, around 4kHz, on the bass channel of the mixer…

I wondered whether I might have found the problem if I had stayed behind instead of going back to the hotel after soundcheck. For me, it was like a bad dream… why was this happening?

At the end of the night, while further discussing the problem with Dale, I insisted that somehow the sound was being induced directly back into the guitar pickups. At this stage, he mentioned that the theatre was fitted with… wait for it… a ‘hearing aid loop’. In case you don’t know, a hearing aid loop is a large coil of wire used to magnetically induce audio into a tiny pickup coil which is fitted to most hearing aids. This allows the hearing aid wearer to hear the program without picking up excessive audience noise, room reverberation, etc.

Such loops are often found in movie theatres and are driven from the theatre sound system, or by an auxiliary amplifier that is connected to the system. This particular loop was driven from its own amplifier alright, but instead of being driven from the main theatre system, which we weren’t using, it had its own special microphone.

The mic involved was hanging surreptitiously from the ceiling, about six metres above the front of the stage! This meant that any sound picked up by the mic was being turned into a powerful magnetic signal by its amplifier and the loop, and was induced straight back into the guitar pickups and re-amplified by the guitar amp!

This explained why Eddie King’s Gibson-style guitar with its humbucking pickups wasn’t affected – humbucking pickups have two out-of-phase windings which make them immune to external magnetic interference, such as may be caused by light dimmers, mains transformers and, of course, hearing aid loops!

Chances are, you’ll never meet a similar fate, although I’ve since heard of a couple of other previous instances of this mysterious problem occurring. This one I shall never forget.