Digital Multitrack In North Wales
David Mellor takes a day trip to the University College of North Wales in Bangor to visit the first studio in Britain to take delivery of an Akai DR1200 digital multitrack recorder.
In the major studios around the world, two manufacturers are slugging it out to be top dog in the field of digital multitrack tape recorders - Sony and Mitsubishi. But they had better watch out because a third Japanese company is sneaking up behind them with a completely new product at a very attractive (for digital multitrack) price.
Akai's DR1200 is a 12-track digital recorder based around the Video 8 cassette format. The Video 8 format was, a few years ago, Sony's attempt to upturn the lead of the VHS format in the domestic video world. I don't think it is unfair to say that it failed, not because of any intrinsic problem, but because it did not offer enough extra over VHS to overcome market inertia. But the Video 8 format lives on in compact video 'camcorders', and the Video 8 cassette has proved useful in other fields such as data storage and now multitrack audio recording.
The DR1200 uses Akai's proprietary ADAM 16-bit format. ADAM, rather predictably, stands for Akai Digital Audio Multitrack. Like a video recorder (and like DAT), the ADAM format uses a rotary head, rather than the stationary heads used by the Sony and Mitsubishi reel-to-reel digital multitracks. The head drum has three record and three playback heads which scan diagonally across the width of the tape, as shown in Figure 1. The data from the 12 audio channels is split up and distributed in such a way that the system can correct for errors caused by dropouts on the tape. Correction is possible even if one playback head is completely dogged and picks up nothing, or if up to half of the tape's width is unreadable. As well as 12 digital tracks, there are two analogue tracks recorded by a separate stationary head for control pulses and for timecode. Figure 2 shows the internal layout.
The complete DR1200 system comes in three units: the main recorder section, the DL1200 autolocator, and the DM1200 meter unit, all of which are necessary for operation. The DR1200 itself is a hefty unit, taking up 7U of rack space and weighing 79 pounds! The manual doesn't suggest that the unit needs rear support in the rack, but at this weight I would certainly recommend it. It is suggested, however, that the rack is bolted to the wall and that a ventilation fan is installed at the top of the rack. It is necessary to have access to the top of the machine as well as the front for the regular head cleaning that is essential, so a few empty units of rack space above the DR1200 will come in handy.
The front panel of the recorder itself has few controls: OPEN/CLOSE to insert or remove a cassette in the cassette compartment; TAPE VIEW to illuminate the compartment; INT, EXT1 and EXT2 to select the sync mode (the DR1200 can operate alone or sync to another DR1200 or to an external synchroniser). There are also a number of indicator LEDs.
Around the back of the machine are 24 XLR connectors for input and output to the digital tracks, and two jacks for input and output to the auxiliary (timecode) track. As this is intended to be a fully professional machine, there are of course no phono sockets. Also on the rear panel are 'D' connectors for digital input/output, synchroniser, digital level meter, autolocator, and error rate counter. Mains input is via a standard IEC connector.
To operate the DR1200, it must first be connected to the DL1200 autolocator and DM1200 meter unit. A mixing console will come in handy too, but you need to know a few things about the level at which the DR1200 works.
As you probably know, an analogue tape recorder produces more distortion as the level on tape increases. There is no hard and fast limit to where this distortion is too much, it's up to the recording engineer. The recorder and mixing console are usually aligned so that the console has plenty of voltage headroom in its output stages, no matter how hard - within reasonable limits - the engineer wants to push the tape. Often, the system is set up so that the peak level will be +8dBu, or 1.95 volts RMS.
A digital recorder, however, produces very little distortion when driven right up to its limit - but go a fraction of a dB over and you will get harsh-sounding clipping. What Akai have done is to align the maximum input level of the DR1200 close to the maximum output level of many mixing consoles. In other words, there is little or no headroom in the console output stages. Peak level on the DR1200 is reached at +19dBu, or 6.9 volts RMS, which is very high by analogue tape recorder standards. This has three ramifications:
- The noise performance of the mixing console is optimised, because you are working at such a high level.
- You will have to learn not to worry about the console meters hitting their end stops when you drive the DR1200 hard (VU meters are normally set up so that 0VU represents a mere +4dBu).
- If your console can't manage output levels as high as +19dBu, you will have to be content with a reduced signal-to-noise ratio on the DR1200.
Though some users may quibble at such high input levels, I think Akai have got it right because they have gone for the best sound quality, rather than compromise by fitting in with conventional practice.
Before making a recording on the DR1200 the cassette tape must be formatted, in much the same way as a floppy disk is formatted before use in a sampler or computer. To do this, a Video 8 cassette of the correct specifications is inserted (since the tape is too thin on long playing Video 8 cassettes, they will be spotted and rejected by the machine) and the formatting function selected. At this point you have a choice of sampling rates, either 44.1 or 48kHz. As you are probably aware, 44.1 kHz is the Compact Disc sampling frequency and 48kHz is the sampling frequency adopted by other digital multitracks. Here, the 44.1kHz rate offers the advantages of a slightly longer playing time and the possibility of +/—6% varispeed being used.
During formatting, a Table Of Contents area is created at the head of the tape which can be used to save autolocator data, and also the track pattern is recorded throughout the full length of the tape. Pulses are also recorded onto the Control track at this time. Once the tape is formatted, we can get down to some digital multitracking.
The DL1200 autolocator is fairly simple to use and can control up to three DR1200 units without recourse to an external synchroniser. This brings the system up to 36 tracks at a rather lower price than the reel-to-reel competition can offer. Along the top of the DL1200 are the status indicators showing which tracks are in Record Ready mode, which are in Play, and which have been digitally delayed. The DR1200 offers independent digital delay on each channel, up to 66 milliseconds. (For orchestral recording, this could offer the interesting possibility of time-aligning separately tracked spot microphones with the overall stereo pair).
Below these status indicators are, naturally, the status buttons. These are nice and big, and are aligned physically with the indicators. There are 12 sets of buttons and indicators, but if more than one DR1200 is being used, they can be switched to control tracks 1-12, 13-24 or 25-36 as necessary. There are two time displays in the centre of the unit. The left-hand display indicates tape time, the right-hand one is multipurpose, showing locate points, pre/post roll memories, punch-in/out points, offset values, etc.
The usual autolocate functions are available, such as search to a stored time reference, automatic punch-in/out, punch-in rehearsal, pre and post roll, etc. The punch-in function is particularly good, with a choice of four crossfade times between 11.6 and 92.8 milliseconds (at 44.1kHz sampling rate). Spot erase is, in theory, possible by programming punch-in/out points which are very close together. In practice, it takes some time to find the correct point on the tape and is more difficult than with an analogue recorder.
Someone has to be the first customer for any new piece of equipment, perhaps taking a bit of a risk, but also being first in line to receive the potential commercial benefits on offer. In a studio situated amongst the buildings of the University College of North Wales in Bangor, there operates a company called Cantor Cyf (Welsh for Cantor Ltd), the first UK owners of an Akai DR1200.
Like many Universities, the University College of North Wales has a music department. As music becomes increasingly technology orientated, students of all kinds of music need to know how to use this technology to artistic advantage. Rather than set up their own music studio, the University has rented space on the campus to Cantor, who in turn hire their services - both technological and educational - to the University. A symbiosis, if you like.
Cantor is run by a team of two, Bryn Jones and Tony Biggin. They work alongside the staff of the University's music department, who are basically pure musicians, and take care of instruction on the technical and computer side of things. Rather than offer courses on recording engineering, the work is music-based, with recording techniques as a necessary adjunct.
Bryn Jones: "Cantor is a professional recording facility with an educational facility as well. We don't actually give detailed technical instruction as such. We are more concerned with the production side of running a studio rather than how the desk works and how the machines work. We leave that to the electronics department.
"We run a course within the Bachelor of Music degree. We give an hour's instruction every week for the first-year students, which introduces them to the technical side of things. In the second year we give instruction in how to use music computers, MIDI, multitrack recording, different kinds of recordings... all the facilities that are available for musicians.
"The second-years spend a day in here every week, which is quite a large part of their teaching. There is also a little studio, which belongs to the University, which has a downmarket version of what we have here, with the same software on the computers. Students can book that in the evenings or whenever for projects, compositions, whatever they want to do.
"We also run a diploma course, which is a full 30-week course for music postgraduates, but we do consider non-qualified musicians who are electronics graduates. Then we run a commercial studio for the rest of the time."
Two things that Cantor can offer - both to students and paying customers such as the BBC and S4C - that most studios can't, is the use of two concert halls, one of them rather grand, which are located close by among the University buildings. There are 16 microphone lines and video links into both halls. There is at least one concert every week, which the students can use to practice their recording techniques. If Cantor's studio is not available, due to an outside booking perhaps, then recordings can be made in the University's own smaller studio. The halls are also used by Cantor as part of their commercial venture, for recording choirs, quartets, and small orchestras.
Cantor's studio is built in a large, high-ceilinged, room in the University. Compared to the old-world charm of the buildings, it looks very modern. The room design is Cantor's own. One consideration they had, besides the budget, was the fact that they were not able to alter any of the structure of the building, which is listed. The studio had to be built so that it could, at some later date, be removed without trace.
Bryn Jones: "I have worked on the principle of 'treat it until it sounds right to me', because I'm the one who has to be here most of the time. What we have here is a very large room. We designed the shell that we have put in the room itself. We designed it so that we have a nice back reflection, but far enough back not to be annoying. We have a nice soft area which doesn't give too many early reflections, though we have made sure that we get a reflection off the ceiling. Although you can't see it, the floor and the roof aren't exactly parallel, there's a slight drift on the roof going up towards the back.
"All the walls are treated so that with the doors shut we can have a concert in there (the hall next door) going full blast with a full orchestra, and with the doors shut you can't hear it. The room is completely soundproofed. We have built a separate inside wall using neoprene rubber to separate it from the floor and ceiling. So we have got two walls, with an air gap, with solid slabs of Rockwool in the wall. The floor is built on Rockwool as well. We put solid slabs of Rockwool on the ground, cut channels in it for cabling, and just laid chipboard on top. Above the suspended ceiling there is a six foot cavity up to the real ceiling."
Cantor's equipment is separated into two areas, which composer Tony Biggin likes to call the 'creative' area and the 'recreative' area. The creative area contains an imposing piece of woodwork which supports an Elka master keyboard, Akai S1000 sampler, other sound producing items, and a couple of Atari STs running Steinberg software.
Bryn Jones: "On this side we've got all the paraphernalia that you would find in a studio. We haven't got lots of the same things, because what we have tried to do is spread our budget out thinly so that we have got a good cross section of everything - especially seeing that we are trying to teach here as well. We are trying to show people as many things as we can."
Centrally located in the recording-orientated area is a TAC Matchless mixing console, which Bryn Jones appreciates for its lack of gimmicks, its clarity, the fact that mix automation can be retro-fitted and, importantly, that it fitted the budget. Monitoring is via a pair of the ubiquitous Yamaha NS10s and also on Bryn Jones designed main speakers.
The multitrack recorder is, of course, the Akai DR1200. But why was digital multitrack necessary, why not analogue?
Bryn Jones: "I have always found analogue to be a restriction in sound quality and, having worked for some years recording digitally in stereo using several formats like the Sony F1, I could always get sounds on two tracks on an F1 that I couldn't achieve on an analogue machine, using whatever noise reduction. Because of that I was absolutely convinced that I had to have a digital multitrack."
And why an Akai DR1200?
"The whole studio has been worked around a budget. The desk had to come up to a certain aural specification that I wanted. We have to record everything, be it multitrack or stereo, digitally. Obviously, when you are working within a budget, there isn't all that much to choose from where digital multitrack recording is concerned. We got the idea of buying something like an AMS AudioFile (a hard disk system). Then we priced the AudioFile and decided that we would hang on and wait and see what happened. We ran for the first three or four months with no multitrack at all. When this one [the DR1200] came along we were initially quite impressed with its performance. Then we got it in and we are still very impressed. If we can get the reliability out of it, we will be buying another one as soon as we have the money, because we want to make it a 24-track system."
Trying out the Akai DR1200 in Cantor's studio was a rewarding experience, although I didn't have chance to record any live music. Still, I had taken along my favourite test CD and I recorded a track onto the DR1200. At a first listening I certainly couldn't discern any significant difference between CD and recording. The operation of the DL1200 autolocator was straightforward, and the DM1200 bargraph meters were nice and clear.
If I were in the market for a digital multitrack, I would definitely be looking at the Akai DR1200, although I would want to give it some rigourous testing in my own studio with equipment that I know. I would also want to see two DR1200's working together in sync, to see how fast the lock-up is. The sound quality is indeed very good, and the facilities perfectly adequate. In fact, the only major drawback I can see is that the running time of a Video 8 cassette on this machine is only 17 minutes maximum (with a P6-90 NTSC standard Video 8 cassette). This is definitely on the short side and could prove a limitation for certain users.
Apart from that, the Akai DR1200 seems to have a lot of potential, bringing digital multitrack down to a level that more studios and perhaps individuals can afford. The sound quality is distinctly better than analogue tape without noise reduction. Comparative tests with reel-to-reel digital multitracks are definitely called for.
Akai UK Ltd, (Contact Details).
Feature by David Mellor
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