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MOTU MIDI Time Piece

Mark of the Unicorn's first piece of hardware is a combined 8x8 MIDI interface/network and smpte synchroniser for the Apple Macintosh. Kendall Wrightson investigates.



When it was released in early 1985, Mark Of The Unicorn's Performer, for the Apple Macintosh, was the first fully working professionally featured MIDI sequencer for any computer. Performer set the Macintosh MIDI sequencing standard over the subsequent 18 months until the arrival of the first major competition, in the shape of Opcode's unimaginatively named Sequencer and Passport's graphically sophisticated Master Tracks Pro (now known as Pro 4). Last year. Opcode's Vision set new sequencing standards and the recent arrival of Dr.T's Beyond and Steinberg's Mac version of Cubase offer the Mac user a level of choice that Atari ST owners have enjoyed for several years.

THE MIDI BOTTLENECK



The Mac has always had the advantage of two bidirectional serial ports — the modem and printer ports — which Performer, like all good Mac sequencers, utilises by allowing each individual track to be assigned to either port (giving 32 MIDI channels). However, even a modest MIDI system can quickly succumb to the spectre of a MIDI bottleneck — the massive data traffic generated by the increased use of Controllers and MIDI mixing can be too much for even two MIDI ports to handle, resulting in anything from small timing jitters to a major chronological hiccup.

Although each Mac sequencer has its own unique features, a level of functionality has now been reached beyond which further innovation is limited by the Mac's MIDI interface, or rather the unwritten conventions that dictate its design. These conventions ignore two very salient facts. The first is that the Mac's serial ports are capable of operating much faster than the current (almost universal) 1 MHz 'standard'. The second is that the serial ports are running so much faster than MIDI itself, that even at 1Mhz, a MIDI interface has plenty of time in which to multiplex data to multiple independent MIDI ports.

MULTIPLEXED SERIAL PORTS



Imagine that you're stacking trays of fruit from a conveyor belt in a factory. If you are receiving trays at the rate of one every minute but a fork-lift only comes to collect them once every eight minutes, then you have three choices: [1] you can either ask production to slow down and send one tray every eight minutes; [2] you can do nothing and hang around wasting time for eight minutes; or [3] you can arrange for eight fork-lifts to come every minute. If you choose the latter option, you have effectively multiplexed your fruit (your data) eight ways.

This is exactly what Mark Of The Unicorn do with their MIDI Time Piece (MTP) — it takes MIDI data from a Mac's serial port and multiplexes it eight ways to give eight fully independent MIDI ports, each offering 16 MIDI channels, making 128 MIDI channels in total.

However it doesn't end there, because two MTPs can be connected to each Macintosh serial port, giving a grand total of four MTPs, 32 independent MIDI ports, and 512 MIDI channels!

The MTP also breaks the second unwritten convention and allows the Mac's serial port to run as fast as it will go; although, even at 1 MHz, the MTP has plenty of time in which to multiplex.

BUT...



The drawback to breaking these MIDI interface conventions, and indeed the reason why it hasn't happened before, is that all MIDI software has to be adapted to make use of it, since the software needs to know how to address 32 MIDI ports rather than just two. Thus the only MIDI sequencer that can currently make use of the MIDI Time Piece's networking abilities is... Performer (Version 3.4).

HARDWARE



Mindful of this not insignificant fact, MTPs can be connected to the Mac in such a way as to appear to normal software as two MIDI ports, whilst still making use of the MTP's eight MIDI Ins and eight MIDI Outs.

Regular MIDI software also requires that the MTP's central three-position front panel switch be set to '1 MHz' rather than 'Fast'. The middle position of the Fast/1 Mhz switch (identified by a modem/printer icon) routes data from the Macintosh's serial ports through to a rear panel DIN 8 socket (labelled with the same icon), and therefore allows a connected modem or printer to be switched in without having to disconnect any MTP cables.

The only other front panel switch is used to determine whether the MIDI Time Piece's eight outputs are numbered 1 to 8 (full left) or 9 to 16 (full right), the latter being the case when two MTPs are connected to one Macintosh serial port. The middle position switches the MTP off.

The rest of the front panel is occupied by activity LEDs for each MIDI In and Out (very useful) plus two further LEDs, one to indicate timecode lock and one for power on, which also blinks when a full frame message is received. Thoughtfully, Mark Of The Unicorn have also placed a MIDI In and Out socket on the front panel to allow a temporary connection to be made without having to grope around the rear panel, where the rest of the MIDI Ins and Outs live.

The rear panel also sports the mains adaptor socket (9V DC), SMPTE In and Out jacks, and three DIN 8 sockets labelled with Network, Mac, and Printer/Modem icons. (The printer/modem port is the through port, as mentioned earlier). The Mac and Network icons are best discussed in relation to the Cable Routing window, which we'll encounter shortly.

ROUTING CONFIGURATIONS



There are many different ways of configuring an MTP setup. The chosen method depends upon the following considerations:

How many MTPs you wish to connect.
Whether you are going to run regular or 'MTP compatible' software.
Whether you want to add a regular MIDI interface to the network.
Whether you want to network a second Macintosh.


Figure 1. Single MTP.


Figure 2. Two MTPs.


Figure 3. Four MTPs (end second Macintosh).


Figure 4. Incorporating a regular interface.


Figure 1 illustrates the connection of a single MIDI Time Piece. When using non-MTP compatible software, the dotted connection should be made and the interface speed switch set to 1 MHz.

Figure 2 shows how two MTPs should be connected, two being the maximum that can be connected to either serial port.

Figure 3 shows how to connect a second Macintosh to a four MTP setup. In fact, a two, three, or four MTP network can utilise a second Macintosh, with both computers able to access the network simultaneously (ie. both running MIDI software) which is a very useful facility for Macintosh-based studios.

Another very interesting MTP advantage for studios, and one which is not given much publicity, is that MIDI Time Piece network cables can be up to 1,000 feet long, whereas standard MIDI cables are limited to 15 metres.

Figure 4 shows one way of incorporating a 'conventional' Macintosh MIDI interface, which will offer a total of 17 MIDI Ins and Outs. Use of a conventional interface will also necessitate setting the speed switch to its '1 MHz' position.

MTP DESK ACCESSORY



Figure 5. MIDI Time Piece Desk Accessary Menu.

With only two front panel switches available, you have no doubt guessed that the MIDI Time Piece is software-controlled from a Macintosh Desk Accessory (DA) — see Figure 5.

The first MTP DA option, Network Configuration, calls up a window which shows how the MTP DA 'sees' the current serial port status, using MacPaint graphics similar to those in Figures 1-4.

Figure 6 shows the Cable Routing window, the MTP DA's second option, which is used to make source-to-destination connections. The window contains Macintosh serial port selector buttons, a 16x16 grid of check boxes for routing MTP MIDI Ins and Outs, an MTP Mac port input/output column/row, and an MTP Network port input/output column/row. There are also two extra boxes at the lower right-hand side of the matrix, which are used for routing data between the MTP's Mac and Network ports, a necessary operation when a conventional MIDI interface is to be connected.

Figure 6. Cable Routing Dialogue Box.


The 16x16 check box grid refers to an MTP's eight MIDI Ins and eight MIDI Outs. There are 16 because each Macintosh serial port can have up to two MTPs connected (MTP 1-8 and MTP 9-16). If only one MTP is connected, then In/Outs 9-16 are irrelevant.

MIDI 'CABLES'



For some reason, Mark Of The Unicorn have chosen to use the word 'cable' to describe what you and I would call a source/destination, or an In/Out. Unfortunately, this doesn't exactly help in understanding the already complicated Cable Routing window.

As both Mac serial ports can support two MTPs, the Macintosh serial port selector buttons select the current port, eg. the modem port in Figure 6. As the MTP's Mac port is always connected to a Macintosh serial port, the Mac icon for the MTP Mac port column/row has a Modem icon above it. (This icon would become a printer icon if the printer port was the currently selected port).

The MTP Network port column/row refers to devices connected to an MTP Network port. This port could be connected to a conventional (or 'regular') interface, as in Figure 4. In such a case, a printer icon would appear above the Network column/row icon.

If two MIDI Time Pieces are connected to a Macintosh serial port, then as you can see from Figures 2 and 3, the MTP's Network port is no longer available, and so its icon no longer appears in the Cable Routing window. In its place a second MTP Mac icon appears, labelled 'Mac 9-16', and the original MTP Mac icon changes to 'Mac 1-8', as shown in Figure 7.

Figure 7. The Cable Routing Dialogue Box changes when multiple MTPs are connected.


ROUTING BETWEEN CONNECTED DEVICES



Routing data between MIDI devices connected to an MTP's MIDI In and Out sockets is straight forward. For example, if a MIDI mother keyboard was connected to the MTP's MIDI In ('Input Cable 1' in Mark Of The Unicorn parlance) and an expander module was connected to MIDI Out ('Output Cable 8'), then the box in column 1, row 8 should be checked (highlighted).

To route one input to all outputs, as with Input Cable 6 in Figure 5, it is not necessary to individually check each box in the Input Cable 6 column. Simply clicking on the number '6' above the Input Cable column instantly checks all the boxes in that column. The same shortcut applies when merging inputs to outputs. For example, clicking the '12' to the left of the Output Cable column merges all inputs to Output 12, as shown in Figure 5 (16-way merging!).

MACINTOSH ROUTING



Apart from the MIDI devices connected to the MTP's MIDI Ins and Outs, there is also another MIDI source/destination connected to an MTP — the Macintosh itself, which, as you will see from Figures 1-4, is always connected to the MTP's Mac port.

Non-MTP compatible software can only 'see' the Macintosh's two serial ports, so it is necessary to make the dotted line connection shown in Figure 1. This allows both Macintosh serial ports to be used, giving 32 MIDI channels as found on most popular 'dual' interfaces.

The control of data flow between the Macintosh and connected MTPs is set up in the Cable Routing window. For non-MTP compatible software, the Mac and Network input/output row/columns route MIDI data from the Macintosh's modem and printer ports. Thus, if a sequencer track is routed to the modem port and you wanted to route that data to MTP MIDI Outs 2, 3, and 4, then boxes 2, 3, and 4 should be checked in the MTP Mac or Network column (depending on which was connected to the modem port). Similarly, to route a keyboard connected to MTP MIDI In 4 to the printer port, then box 4 of the MTP Printer row should be checked.

There isn't any 'MTP compatible' software yet, apart from Performer 3.4, so I'm not going to describe the extremely convoluted Cable Routing window possibilities, particularly as MTP compatible software can override Cable Routing settings, as is the case with Performer 3.4.

MTP AND PERFORMER 3.4



Performer Version 3.4 has been modified so that tracks can be assigned to any of the 17 'cables' on each serial port. To this end, Version 3.4 incorporates a new window called MIDI Channels (illustrated in Figure 8).

Figure 8.


Each Performer track can be assigned to any MIDI channel(s) on any of the 17 MTP output cables on either port. Cable 17 refers to the fact that a regular interface can be connected to the MTP's Network or Mac ports, as in Figure 4. Here the example is a dual interface: the modem port sees 17 cables and the printer port sees nine. As Performer assigns tracks from its own window (and automatically 'cable-ises' MIDI data), the last two columns in the Cable Routing window are overridden. This also allows the user to name MIDI instruments connected to the MTP(s) and refer to them by name, rather than having to remember the current channel, cable, and port status for up to 34 devices!

Although Performer takes over the routing of data to and from the Macintosh, the routing of data between connected MIDI devices is still decided from the MTP Desk Accessory. This can cause problems if Performer is patching through, or through-channelising data, because you might inadvertently route data from Device A to Device B in Performer as well as in the Cable Routing window. This will cause what the MTP user guide refers to as "a number of MIDI problems". We are not enlightened any further as to the nature of these problems, but 'crash' is one that immediately springs to mind!

Figure 9. Channel mapping.


CHANNEL MAPPING & EVENT MUTING



The Channel Mapping and Event Muting windows are, thankfully, much easier to understand. They utilise the familiar 16x16 check box grid (source MIDI channel x destination MIDI channel) and 16 cable buttons. So cable 1, source channel 1 can be mapped to destination channel 16 (see Figure 9).

The Event Muting window is similar, with the 16x16 matrix representing MIDI channel x MIDI cable, with radio buttons used to filter Channel and System messages.

The state of the Cable Routing, Channel Mapping, and Event Muting windows can be saved and loaded from the MTP Desk Accessory menu, with 'Save As Default' writing to battery-backed RAM in the MIDI Time Piece itself, which is automatically loaded when the MTP is switched on. If the MTP unit is not switched on for a few weeks, the default data will be lost, so it is also possible to save the default file to disk. Perhaps it might have been better if Mark Of The Unicorn had used an EEPROM (Electrically Erasable Programmable Read Only Memory) as employed in Emu Systems' Emax sampler, rather than battery-backed RAM.

SYNCHRONISATION



The synchronisation side of the MTP is controlled from the MIDI Sync, Stripe SMPTE, and SMPTE Reader windows.

The Stripe SMPTE window offers all four timecode rates and allows SMPTE/EBU timecode to be written from any of up to four connected MTPs. There are five SMPTE output levels available, from -9dB to +3dB (in 3dB steps) referenced to -10dB. For +4dB professional equipment, the signal will need to be boosted.

The SMPTE Reader window displays the current time, the frame rate/format, and which MTP unit is receiving it. Unfortunately, it is not possible to run Performer and view the SMPTE Reader window simultaneously.

The MIDI Sync window offers a choice between SMPTE-to-MTC or SMPTE-to-DTLe conversion. DTLe is an enhanced (hence the lowercase 'e' suffix) version of Mark Of The Unicorn's completely non-standard Direct Time Lock protocol, which sends four frame advance messages per frame compared to (MTC) MIDI Time Code's one. MTC or DTLe can then be routed to the required output cables and/or to the Mac itself.

THE GOOD, THE BAD...



The synchronisation side of the MTP is generally excellent, with very fast lock-up, the only negative point being the adoption of the semi-professional -10dB output level — an odd choice given that the MIDI Time Piece is aimed at the professional user.

The Cable Routing window is the most difficult part of MIDI Time Piece to understand, as the manufacturers readily admit in their user guide. The spurious use of the word 'cable' only makes matters worse. It would have been better to allow MIDI devices to be named from within the Cable Routing window, and for the MTP Desk Accessory to 'recognise' a device by name (once defined), as Performer can. Routing could then be a simple case of listing source devices and destination devices, highlighting a source device and double-clicking on the desired destination device. This would free the user (particularly infrequent users) from having to remember what device is connected to each port and cable, and on what MIDI channel.

CONCLUSION



In an industry which has proven again and again that compatibility is everything, Mark Of The Unicorn stand out as a company which still seems to believe it can sell products on the back of non-standard software and hardware. For example, since Version 2 of Performer Mark Of The Unicorn has used non-standard radio buttons, check boxes, and pushbuttons, which is off-putting to the new user and requires half a page of explanation in the MTP manual. More importantly, Performer still cannot read MIDI Time Code. Do they expect everyone else to adopt DTL, and now DTLe?

I don't think so. I believe they expect potential sequencer purchasers to buy Performer on the basis that DTLe is better than the standard MTC, and on the basis that Performer is now MTP compatible. However, I feel certain the consumer looks at it the other way around — who is going to buy a MIDI Time Piece when it is only compatible with Performer? After all, as stated in the opening paragraphs, there are now five major professional Macintosh MIDI sequencers to choose from, and brand switching is rare.

With MTP now available, however, the case for switching to Performer is very strong — particularly for professional Macintosh-based studios, who must surely find the ability to network up to four MTPs and two Macs extremely appealing. Add to this the extremely useful facility of 16-way merging, the improvements in MIDI data bottlenecks, and the ability to read/write SMPTE/EBU from any connected MIDI Time Piece, and Performer's professional appeal becomes clear.

For non-Performer users, an MTP can offer eight non-independent MIDI Ins and Outs (more than Passport's MIDI Transport or Opcode's Studio 3 interfaces offer), 8-way merging (which neither Passport nor Opcode offer), built-in synchronisation, and an unlimited number of matrix patches through the use of Desk Accessory control — all for £499 inc VAT.

On a more general note, the idea of multiplexing the Mac's serial ports is an excellent idea, and one can only hope that Mark Of The Unicorn's 'standard' is widely adopted and perhaps incorporated into Apple's own MIDI Manager.

One final point: it is important to point out that MIDI bottlenecks cannot be overcome with a multitimbral expander which offers only one MIDI In — manufacturers please note!

FURTHER INFORMATION

MIDI Time Piece £499 inc VAT.
Performer Version 3.4 £395 inc VAT.

MCMXCIX, (Contact Details).


Also featuring gear in this article



Previous Article in this issue

Adventures In Midiland

Next article in this issue

Software Support


Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.

 

Sound On Sound - Sep 1990

Donated by: Bert Jansch / Adam Jansch

Previous article in this issue:

> Adventures In Midiland

Next article in this issue:

> Software Support


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