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Studios And Recording

Studios And Recording; Instruments And Equipment; Etcetera.

New Dimensions In Sound Recording

HAVE you ever wished that you'd placed a complex mic setup somewhere else, but didn't realise until after you'd done the session? Practically everyone suffers from this problem, whether it's caused by a drooping mic stand in the studio or a broken string on your coincident pair 300ft up in the Albert Hall.

Now, thanks to the combined efforts of Calrec, the UK microphone manufacturers, and the mathematical wizards under Michael Gerzon at Oxford's Mathematical Institute, there's a mic that you can point in any direction, up, down or around, and change the polar diagram — after you've actually got the thing on tape.

The Calrec Soundfield microphone, unveiled at AES Hamburg, is now available and offers all this and more. It was developed as a result of NRDC-financed research by Gerzon and Co into methods of 'surround-sound' or 'Ambisonic' reproduction. As you're probably aware, most of the so-called 'Quadraphonic' recording techniques previously developed (the correct term, by the way, is 'Quadrisonic') are pretty abysmal, and restrict the creative scope of the engineer in many nasty ways, by virtue of their inefficiency. One big cause of this is the numerous attempts to squeeze four channels into two: which just isn't on. But the Gerzon system, code-named 45J, gets round all this by mathematically reducing the number of channels required for true 'surround-sound' reproduction to 2½ (the half being a band-limited channel). This makes it far easier to matrix for disc and radio applications, with none of the problems associated with previous techniques.

Although the full replay system for Ambisonic reproduction still requires the regulation four speakers minimum for horizontal surround-sound reproduction, you only need three channels on tape to provide all the information, plus, of course, an encoder and decoder. The addition of a fourth tape (or whatever) channel makes full Periphony ('sound-around-the-edge') including height information, possible. It is this B-Format signal (consisting of mono, plus x, y, and z-axis signals) that is used in the Calrec Soundfield mic.

The mic itself consists of four capsules mounted in a tetrahedral array, electronically corrected to give true coincidence rather than the approximations suffered with discrete microphones. Mathematically, the mic is similar to a coincident pair, but in three dimensions. The signals from the capsules are matrixed into the full B-Format, which is then recorded. On playback, a control unit enables the engineer to adjust the directional positioning of the recorded signal, change its polar diagram, and even 'raise' or 'lower' the apparent mic position. This latter function will enable classical recording engineers to eliminate the disturbing tendency of crossed-pair recordings to make the listener feel as if he/she is suspended like a bat from the concert-hall rafters, even if that's where the microphone actually was. A knob enables the engineer to aurally 'lower the mic into the audience' after the event. Surprisingly, the equations involved in providing this facility are closely related to relativistic physics!

In the rock field, this mic opens up all kinds of possibilities for recording a band on four tracks with one mic, then remixing on to the remaining tracks a decoded version of the original recording in which the mic is 'aimed' successively at the different instruments, in mono or stereo.

But apart from these applications, the 45J system opens up wide possibilities for Ambisonic recording and replay. At last there is a system which gives true 'surround-sound' reproduction. It relates closely to the already-successful BBC ambi system Matrix H. Decoders are already on the market offering full B-format reproduction and 45J matrix inputs, along with BBC Matrix H for as little as £45. We will be examining 45J in detail at a later date, along with a report on practical research that is going on at the moment to make it available.

The system is remarkable to hear, and, with good publicity, it will certainly take its place in the music business as 'the system we've all been waiting for'. Objections from the manufacturers of other, inferior systems can only be regarded as rearguard actions.

KPM Update

KPM Studios, in the heart of London's Denmark Street, has recently refitted and reopened. The studio has been completely redesigned and incorporates a custom Helios Electronics 32/24 desk, designed by the studio's engineering staff under the direction of technical manager George Chkiantz. The desk interfaces with a Studer A80, currently 16-track, but soon to be upgraded to 24. The studio has been substantially re-designed acoustically by Keith Slaughter and incorporates special bass-absorbers and other acoustic treatment. The reconstruction of the studio itself, co-ordinated by admin manager Phil Sharp, incorporates a drum-booth, vocal-booth and listening room, and includes rebuilt screens and a substantially 'dead' sound for maximum separation. Monitoring remains with Tannoy Lockwoods and Leak TL50's with smaller Tannoys for studio playback and the listening room.

The desk incorporates a number of innovations including an automatic overdub facility which self-selects appropriate foldback and monitoring sources for tracks being worked on. It also enables record monitoring functions to be controlled solely by the multitrack remote status.

We'll be looking at the studio in greater detail in the future. KPM Sound Studios, (Contact Details).

High Speed Revox

THE renowned Revox B77 is now available from the UK distributors, FWO Bauch Ltd, in a high speed (7½/15 in/s) format in both IEC and NAB equalised versions. British rrp is £575.

MSS 8-Track Mobile

MOBILE Sound Services, Claygate, Surrey have set up a new 8-track mobile recording unit, with Scully 1in 8-track, Soundcraft 16/8 console, Revox mastering machines, Quad/Tannoy monitoring and a good number of ancillary goodies, with microphones by AKG and Shure. The mobile costs just £9 per hour, with cheaper rates for multiday bookings. The facility carries its own screens, and offers a full CCTV setup.

MSS was set up by Paul Friend and Charles Griffin to bring the advantages of recording in any environment financially within the reach of every creative individual concerned with music production. MSS, (Contact Details).

New AKG Mic

A BETTER general purpose mic than the good old D202 would be hard to imagine. We've been using them for years for everything, from outdoor coincident-pair effects-recording to studio drum mikes. But now AKG have surpassed themselves with the D222, which is no doubt to follow the 202 into the realms of recording near-legend.

The new mic looks just like the 202, but is more advanced internally. It includes separate high- and low-frequency transducers, an acoustic tube for the LF end and rear-entry slots. The bass-cut switch from the 202 has been carried over, and gives 0, -6, -12dB cut at 50Hz. The D222 is available in DIN or XLR-connector terminations and also includes a preset crossover adjustment. The mic capsule can be changed very quickly and has built-in popshield. The most obvious difference is the size: the D222 is only two-thirds the size of the 202. Price is about £80.

AKG have also announced a new compact modular mixer for mobile recording use. The SM 2000 is a basic 6/2 unit, but it can be expanded to up to 16 inputs. Standard fittings include phantom power (12/48v) two-band eq, two monitor outputs, one echo send and two echo-returns. Inputs are low-impedance balanced and floating. They can take either standard dynamic or condenser mics and include switchable attenuator and rumble filter, plus RF suppression. Output metering is via two illuminated VUs. Outputs are unbalanced, as are the monitor outs which can look at the desk outputs or PFL.

The SM 2000 can be driven from AC or batteries and incorporates DIN or XLR sockets for inputs and IEC power input socket.

UK: AKG Acoustics Ltd, (Contact Details).

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