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Function Junction

MIDI Patchbay

Audio Architecture's Function Junction range of MIDI patchbays offers up to 16 x 64 MIDI routing with MIDI merging, sophisticated MIDI processing and mother keyboard emulation. Kendall Wrightson investigates.

Audio Architecture is a British company set up by Executive Audio - distributors of sound libraries and the like - with the sole aim of manufacturing a new range of MIDI patchbay/processors. The devices in question bear the name 'Function Junction' and their designer is one Bill Marshal, well known to many pro musicians for his excellent customisation services.

In designing the Function Junction range, Bill has addressed a gap in the market which the big three Japanese companies seem reluctant to fill. Both Akai and Roland offer no-nonsense MIDI patchbays (the 4x6 ME30P and 8x8 A880 respectively), leaving the market for more sophisticated devices to the German company MIDITemp (the 8x8 PMM88) and the American Digital Music Corporation (the 6x8 DMX8).

With FX units, mixers and now multitrack machines sporting MIDI sockets, Audio Architecture wisely offer both an 8 x 8 and a 16 x 16 configuration (the Function Junction and Function Junction Plus respectively). The latter can be expanded further by adding up to three Plus 16 expanders which each provide an extra 16 MIDI Outs, giving a maximum configuration of 16 x 64.

In this respect, the Function Junction Plus is very similar to the discontinued Sycologic Ml6, which also offered 16 x 64 capability. However, unlike the M16 the Function Junction offers MIDI merging, mother keyboard emulation and a wealth of processing facilities which make it an invaluable tool both on stage and in the studio.


The 1U rackmount Function Junction and 2U Function Junction Plus are unusually heavy due to their 2.5 mm thick metal cases - a wise precaution which provides real protection from the inevitable knocks of life on the road.

The light grey casing is tastefully offset by red lettering to match the unusual blood red 16 x 2 character electroluminescent display (32 x 2 on the Plus). The three keys to the right of the display - Enter and two cursor buttons - offer display navigation and data entry. Next come four mode buttons (with corresponding LEDs) and two rows of eight numbered keys (16 on the Plus) which make and break connections or provide parameter selection depending on which mode is currently selected.

A single red button labelled Reset transmits an All Notes Off message to each output and, if held for longer than three seconds, sends individual Note Off commands for every note on every MIDI channel on every output (a facility intended for older synths which do not recognise the All Notes Off command). In addition to the power switch and footswitch socket, the Function Junction Plus front panel also provides a socket labelled Remote, for which Audio Architecture intend to supply a remote control "if there is enough demand".

The rear panel is dominated by eight MIDI In and eight MIDI Out sockets (16x16 on the Plus). The Function Junction Plus also features an RS232 connector to accommodate a Plus 16 expander. The rear panel mains Eurosocket offers both 110V and 240V AC operation.


There are five operation modes. Patch Select is the normal operating mode, and the editing modes (Connect, Solo, Process and System) are available from front panel buttons. The Function Junction has 64 Patches in which to store routing/processing configurations, which should be plenty for even the most demanding of live sets. The last Patch used is automatically recalled at power up - handy for studio use.

Each Function Junction Patch can be selected by scrolling the display, via a footswitch, or from an external MIDI device (particularly useful for performance). In the latter case the Function Junction can be set to receive a program change message on any input/channel.

Figure 1. Function Junction Patch Select mode display

The Patch Select mode display shows the current patch number and name. The other half of the display lists the eight (or 16) outputs on the top line with the eight (or 16) inputs underneath. Thus in the example in Figure 1, input 2 is routed to output 1, input 5 is routed to output 3 and input 4 is routed to output 5. The 'm' under output 8 denotes that several inputs are merged to output 8.

The terminology here is a little unfortunate - it would have been better to refer to the Function Junction's inputs and outputs as 'sources' and 'destinations', since the former convention can lead to confusion with the MIDI Ins and Outs of connected devices. For example, say you wanted your D50 to play a DX7. In the latter case the thought process would be "source D50, destination DX7"; easy. With the Function Junction's system you have to think, "right I want the D50 Out to go to the Function Junction In, then the Function Junction Out to go to the DX7 In".

Pressing the Enter key in Patch Select mode reveals two further displays - the MIDI Activity and System Loading displays. Any data which is to be processed in some way (merged, transposed, etc) has to go via the Function Junction's microprocessor which then performs the necessary number crunching. Clearly there is a limit to the amount of information that the Function Junction can process at any moment, and the System Loading screen displays this 'loading factor' as a percentage. Anything above 80% will result in possible MIDI logjam and/or data corruption.

Full marks to Audio Architecture here - no other manufacturer provides such a display, which means that owners of other systems have no real idea what their system can actually cope with, and no way of verifying suspected MIDI logjam. It's difficult to give typical system loading figures, but as a rough guide I found that a MIDI sequencer transmitting 12 tracks of dense information including several controllers (with a little Function Junction filtering on two inputs) gave an average 20% reading on the display. At the other extreme, the Function Junction definitely can't handle more than one input of system exclusive data.


Routing Ins to Outs is performed in the Connect mode, where the display lists the Outs on the top line and the Ins below. The desired output (destination) is selected by pressing one of the eight (16) Out keys. Pressing an input key makes the connection, pressing it again breaks the connection. As on the Patch Select display, connecting more than one source to any destination changes the display to an 'm'. To check exactly which inputs are merged, it's necessary to enter Solo mode, which not only displays the answer but also solos MIDI data. Flanging notes are therefore a distinct possibility if you are unlucky enough to press solo between a Note On and its corresponding Note Off.

Although selecting outputs before inputs is not an ideal way of working, making connections is no easier on any of the Function Junction's major competitors (without the aid of editor/librarian software), and in any case once you've actually made and stored the desired connections, the Function Junction's non-volatile memory and memory protect facility should keep it safe.

The Function Junction is limited to 12 connections in any one Patch, which in practice doesn't impose any operational restrictions. For example, say you had the following eight pieces of kit: a sequencer, three keyboards, two modules, a drum machine and a MIDIpad. A complicated Patch might see the three keyboards, drum machine and MIDIpad all merged to the sequencer's MIDI In (five connections), while the sequencer's MIDI Out is connected to the three keyboards, the drum machine and the two modules (six connections), making 11 links in total. The Function Junction Plus allows 16 connections, and a Plus 16 adds a further 16 connections up to a maximum of 64.


MIDI merging, as above, allows several musicians to access a single multi-timbral module, and is a great live performance feature. Another is the Function Junction's ability to store up to 16 Cues with each Patch. A Cue consists of a MIDI program change and a MIDI volume value. When a Function Junction Patch is recalled, the Cues are transmitted, configuring connected MIDI gear with the correct sounds and volume. Each Function Junction Patch can also transmit MIDI clocks (at a user defined tempo) from any combination of outputs. The clock begins immediately a patch is recalled, or can be started with a footswitch.

As I mentioned earlier, Function Junction Patches can be recalled by pressing the footswitch, over MIDI, or by scrolling through the display. Great care must be taken in the latter case because if a Patch is accidentally recalled by scrolling too far, the Function Junction will transmit its Cues, and if the MIDI clock facility is used, that could set off your drum machine or sequencer. This is bad enough, but imagine if your accidental patch change set off a lengthy hard disk load! It might be a good idea if Audio Architecture were to update their software so that a front panel Patch selection is not completed until the Enter button is pressed. In the meantime, these problems can be avoided by selecting Function Junction Patches via MIDI.


Unlike other systems where processing is applied to the input or output, the Function Junction deals with 'multiple connections' and 'single selections'. The former mode is only available when a Patch contains merged inputs, and effectively applies processing to a single Function Junction MIDI In, and the latter mode applies processing to a single 'connection' (ie. In2 to Out1) where no merging is involved. Connections are assigned the letters A to L, so in the Patch in Figure 1, connection A would be In2 - Out1, B would be In5 - Out3, C would be In4 - Out5. This system is rather complicated, because although the display may read "filter/transpose/delay (etc.) on Conn C", you then have to remember what connection C is. Can you remember without reading back? No, neither can I. The other problem is that 'connection C' is not the same in each Function Junction Patch, nor will it necessarily remain the same within a Patch if you make any new connections.


Anyway, having sorted out your connections, you'll find that the Function Junction has a wealth of processing delights to apply to them. The Zone facility emulates a mother keyboard by allowing any input to be split 12 ways (16 in the Plus) for split keyboard work, each zone playing a separate MIDI output and/or channel. This means, for example, that the bottom octave of any keyboard could address a DX7, the next three octaves a D50 and the rest of the keyboard a Proteus piano. Zones can also overlap to provide layering, so in our above example we could add another Zone to play a Proteus string sound over the entire keyboard. By setting no note limits, Zones can also be used to channelise data - useful for routing data to an old synth which can only receive in Omni mode.

Other performance facilities include transposition (useful in building layered patches), velocity switching/cross fading (ditto) and velocity compression, the latter being ideal for matching different keyboard responses (if you doubt the usefulness of this facility, just try playing a DX7 from an Emulator 2).


The Function Junction's Delay effects processor can be thought of a full bandwidth echo unit for MIDI devices, or as a way of building more complex synth patches by delaying the MIDI data to several connected synths. A delay of up to 2.5 seconds is possible, defined in milliseconds, or as a tempo in bpm (40 to 240). Echo parameters include repeats (0 to 15), velocity offset (to set up an echo decay or gain) and transpose. Any transposition can be set to increase or decrease in pitch with each repeat, providing Lexicon PCM70 type effects.

Further 'Delay Special FX' parameters offer three more facilities: Delay Auxiliary Output, which sends the delayed signal to an alternate output/channel. Bounce Main Output To Auxiliary, which sends the echo to both main and auxiliary outputs; Channel Increment, which sends each repeat to a progressively incrementing MIDI channel. There's lots of fun to be had here, and with 64 patches, there's plenty of room for experimentation.

Further processing facilities include filtering and controller conversion. The latter is a very useful facility allowing, for example, a DX breath controller to control a parameter on any synth.


In the world of MIDI patchbays, besides the £449 PMM88 (reviewed SOS May 90) and the £339 DMC MX8 (reviewed Aug 88), Macintosh and Atari owners can choose from a wide variety of MIDI patchbays which all offer various special features including multiple independent MIDI Outs, higher throughput and built in SMPTE synchronisation.

However the computer-based units are not designed for a life on the road, and none offer the advanced processing or mother keyboard emulation found in stand alone units like the £429 Function Junction. The PMM88 and Function Junction cost roughly the same, and offer more or less equal functionality. The PMM88 has 128 patches, and the ability to change its patches from two independent sources, giving two musicians the ability to control it in live performance. On the other hand it doesn't provide the Function Junction's sophisticated MIDI delay, or its facility to map one controller to another.

One of the Sycologic M16's most useful facilities was its ability to name connected instruments. This is impossible on both the Function Junction and the PMM88, though the Function Junction does at least offer a decent display rather than the PMM88's 3-character LED. DMC offer a £70 Atari editor/librarian for their DMX8 which allows instruments to be named, and Audio Architecture say something similar is in the pipeline for the Function Junction.

Of the two versions of the Function Junction, the 16 x 16 Plus is certainly the more interesting unit, particularly as it is further expandable to 16 x 64. Waldorf (of Microwave fame) recently announced a 15 x 15 patchbay with two way merging called the MB 15, but it doesn't begin to compete with the Function Junction because it offers no processing or mother keyboard emulation facilities.

In conclusion, it's great to see a British music product competing so well against American and European competition, and there's no doubt in my mind that the Function Junction (particularly the Plus) is a winner.


Function Junction £429 inc VAT.
Function Junction Plus £699 inc VAT.

Executive Audio Ltd, (Contact Details).

Also featuring gear in this article

Previous Article in this issue

Shape Of Things To Come

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Dave Stewart's Music Seminar

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 - Dec 1990

Previous article in this issue:

> Shape Of Things To Come

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