KENTON electronics

MidiStream

MidiStreamMidiStream

MidiStream

UHF Wireless MIDI System

Operating Manual

Introduction

Congratulations on your purchase of the

MidiStream

UHF wireless MIDI system. The

MidiStream

system is very easy to use, but please take a few moments to read through the manual to avoid any

operational difficulties.

MidiStream

has been designed specifically to address the problems unique to MIDI data transfer. It

combines a high data rate with extremely low latency and low dropout rate. Should dropouts occur due

to going out of range or interference from other sources,

MidiStream

is designed to handle these

events without leaving notes stuck on.

The

MidiStream

system works in the 868 to 870MHz pan European licence free band. At the present it

is available with one frequency of 869.85MHz which means that you cannot use two

MidiStream

units

close to one another, however we plan to make other frequencies available in the future to enable

multiple units to be used in the same vicinity.

About the Transmitter Unit

MIDI In socket

Connect your keyboard, wind controller or other MIDI device to this input socket using a standard MIDI

cable.

Antenna

The antenna fitted on the

MidiStream

transmitter is not removable, do not attempt to unscrew it! Try to

ensure that the antenna is straight when operational and if possible is placed away from other solid

objects, particularly metal ones

On/Off switch

When this switch is on, the

MidiStream

transmitter is operational and waiting for MIDI data.

LED

This LED has four functions:

1) The LED will give a steady glow when the

MidiStream

transmitter is on,

2) When MIDI data is received the led will flicker in response to the incoming MIDI signal.

3) If the battery voltage is low (6.5 volts or less), this LED will flash regularly on and off

4) If the unit enters power save state, the led will blink briefly every two seconds

Changing the battery:

When the LED indicates that the battery voltage is low, it is time to change the battery.

Unscrew the knurled knob on the bottom of the unit and open the flap. Turn the unit so that the battery

falls out under it’s own weight, but try to catch it so as not to stress the connecting wires.

If the battery voltage falls below about 4.5 volts the

MidiStream

transmitter will no longer work.

About the Receiver Unit

Power on/off switch

Push this switch

to turn the unit on.

DC IN 9-12V

Plug the supplied power adapter into here. The unit will take an adapter with an output in the range of

9-12V either regulated or unregulated. The socket is a 2.1mm type with centre positive. Do not use an

adaptor with an output voltage higher than 12V, and the

MidiStream

must not share an adaptor with

any other device. Failure to observe this will invalidate your warranty, and will probably damage the

other device, the

MidiStream

and/or the power supply

MIDI Out

This output gives a copy of the MIDI data which was sent to the transmitter. Connect a MIDI lead from

here to the MIDI In of your sound module, computer or other MIDI equipment

Antennas A & B

The

MidiStream

receiver is what is known as a diversity system. This means that it has two complete

receivers, each with their own antenna, plus a system which arbitrates between the two incoming data

streams, so that if one antenna is not receiving the signal from the transmitter, the chances are that the

other one will be.

The antenna connections are via BNC type connectors. To attach the supplied antennas, push them

onto the BNC plugs attached to the

MidiStream

receiver and then turn the knurled outer ring clockwise

until a click is felt. Ensure that when operating the

MidiStream

receiver, the antennas have as much

free space around them as possible, preferably keeping them away from metal objects. It is suggested

that, rather than mounting the

MidiStream

receiver inside a rack system, the receiver is placed on top

of the rack during operation. If the

MidiStream

receiver must be mounted in a rack, then external

antennas

must

be used and placed on top of the rack, or other suitable place away from interference

sources, during operation. Under

circumstances should the antennas be inside the rack, even with

the receiver turned back to front, as reception will still be severely impaired due to reflections from

other metalwork and the general high background noise level typical of a rack.

Status LEDs

MidiStream

has four status LEDs which have the following functions:

ON (Blue) Indicates that power is on. Flashing means

transmitter

battery is low.

MIDI (Orange) Indicates that MIDI data is being received.

RF-A (Green) Indicates that valid data is being received by Antenna A

RF-B (Green) Indicates that valid data is being received by Antenna B

Ideally both RF-A and RF-B should be constantly lit while the transmitter unit is on. Try to position the

receiver where you get RF-A and B lit constantly in normal operation. Don’t worry too much about the

occasional flicker of one or other, but if both go out at the same time, you have lost your link.

If the transmitter is turned off (or power save is active) then the RF-A and B LEDs will go out.

Getting the best out of the MidiStream system

Optimal placing of the receiver and transmitter

Ideally aim for line-of-sight communication between transmitter and receiver. Try and get the receiver

as high as reasonably possible (put it on top of your rack, not in it) and away from other objects,

particularly metal ones. If you can keep the transmitter away from your body, so much the better,

ideally mount the transmitter on your instrument or carry strap.

Range

The

MidiStream

system has a range of up to 100 metres in open space or about 30 metres indoors,

although this can be reduced by solid objects in the way. As the receiver uses BNC connectors for the

antennas, you can use external / remote antennas if circumstances require. Speak to Kenton if you

want to do this as we can advise.

Using in a rack system

Don’t mount the

MidiStream

receiver inside a rack unless you use antennas placed outside the rack.

Kenton can advise on suitable antennas for use with a rack mounted receiver. Kenton intend to

produce a rackmount kit for the receiver in the future, which will include suitable external antennas.

Exposure to radio frequency energy and potential harmful effects

The transmitter operates at an extremely low power of 5 milliwatts or less, (somewhat less than a

typical mobile phone) however you should be aware that the effects of radio frequency energy on the

human body are not fully known at this time and exposure should be minimised wherever possible. As

mentioned above, if you can keep the transmitter away from your body, so much the better.

Rechargeable batteries

You may find it more economical to use rechargeable batteries in the transmitter. Kenton recommend

that you have two rechargeable batteries, one inside the transmitter, and one on charge. Kenton can

supply high capacity rechargeable batteries and chargers suitable for use with the

MidiStream

transmitter.

The rechargeable batteries we supply have a capacity of 250mAH (most are 150mAH) which means

that you can operate the transmitter for about 5 hours continuously on one charge. Contact us for more

details.

Power save mode

If the system is likely to be used in a situation where there are long idle times between MIDI messages

(many minutes), you can enable power save mode in the transmitter to increase battery life. To control

power save mode, you need to send one of the following SysEx messages to the transmitter :

To enable power save mode and set timeout, send F0 00 20 13 0B 00 00

To disable power save mode (always on), send F0 00 20 13 0B 00 00 00 F7

Where the strings given above are in hexadecimal and

is the time in minutes before the unit turns

itself off – values 1 to 127 minutes are valid times until turn off, and 0 means the unit stays on all the

time.

must never be more than 127 decimal (7Fh). For example F0 00 20 13 0B 00 00 3C F7 will

set the timeout to 60 minutes (3C is the hexadecimal representation of 60). See the next page for more

examples and a decimal to hex conversion chart. Any setting is stored in non-volatile memory, factory

default value is ‘always on’)

When power save mode is enabled, the transmitter will stop transmitting RF (radio frequency) if no

MIDI message has been received for a pre-determined time (set as

above). You will know that the

transmitter has stopped because the two LEDs, RF-A and RF-B on the receiver, will go out and the led

on the transmitter unit will blink briefly every two seconds. As soon as a new MIDI message is received

the transmitter will turn back on, but be aware that the turn-on and re-synchronisation process takes a

few milliseconds so the first message will be delayed very slightly, although probably not noticeably.

Although the unit uses less power when the transmitter is stopped, it doesn’t reduce power

consumption to zero. Typically power consumption is reduced to one third of normal when the

transmitter RF section is shut down. Power consumption is

only

reduced when the timeout has

occurred and the RF section has shut down, otherwise power consumption is normal.

For the unit to shut down the transmitter RF section in power save mode, it must receive

no MIDI

messages of any kind

during the timeout period. If your MIDI instrument constantly sends active

sensing messages then the transmitter RF section will never shut down and no power will be saved.

Uses for the MidiStream system

Although the

MidiStream

system was originally designed with instruments such as the AX-1 in mind,

many other uses have been suggested since. The main other instruments are wind controllers such as

the WX-5 and MIDI accordions. As well as those uses,

MidiStream

can be used in theatres or other

venues to couple a front-of-house MIDI sound or lighting desk to slave units on stage.

MIDI throughput

MidiStream

has a very low latency and high MIDI throughput. It handles all MIDI messages including

Clock and SysEx messages, however, try to avoid very large SysEx dumps (1k or more). If you need to

send very large dumps, try to split them up into blocks with a few milliseconds between each block.

MIDIOX can do this. MIDIOX is an extremely useful utility and you can download it for free from

www.midiox.com

Note hangs & controller updates

MidiStream

has been especially designed to make note hangs extremely unlikely. If you go out of

range of the receiver or the signal gets interrupted, all current notes will be turned off.

When the transmitter is back in range, the current value for major controllers, such as MIDI volume,

modulation wheel, pitch-bend, breath control & program change will be re-synchronised with the most

recent values which were sent to the transmitter. Notes however will not be turned back on again.

More about power save mode

Example strings for a selection of times

5 minutes F0 00 20 13 0B 00 00 05 F7

10 minutes F0 00 20 13 0B 00 00 0A F7

15 minutes F0 00 20 13 0B 00 00 0F F7

20 minutes F0 00 20 13 0B 00 00 14 F7

25 minutes F0 00 20 13 0B 00 00 19 F7

30 minutes F0 00 20 13 0B 00 00 1E F7

40 minutes F0 00 20 13 0B 00 00 28 F7

50 minutes F0 00 20 13 0B 00 00 32 F7

60 minutes F0 00 20 13 0B 00 00 3C F7

70 minutes F0 00 20 13 0B 00 00 46 F7

80 minutes F0 00 20 13 0B 00 00 50 F7

90 minutes F0 00 20 13 0B 00 00 5A F7

100 minutes F0 00 20 13 0B 00 00 64 F7

110 minutes F0 00 20 13 0B 00 00 6E F7

120 minutes F0 00 20 13 0B 00 00 78 F7

127 minutes F0 00 20 13 0B 00 00 7F F7 maximum timeout period permissible

Always on F0 00 20 13 0B 00 00 00 F7 never times out

Decimal to Hex conversion chart

Decimal Hex

0 00

1 01

2 02

3 03

4 04

5 05

6 06

7 07

8 08

9 09

10 0A

11 0B

12 0C

13 0D

14 0E

15 0F

16 10 numbers then continues in a similar fashion

17 11 etc.

Details of the MidiStream SysEx messages

SysEx messages exclusive to the

MidiStream

system are made up as follows:

[1]

- Begin SysEx command

[2]

- Company ident first byte

[3]

- Company ident second byte

[4]

- Company ident third byte

[5]

- Product code –

MidiStream

System

[6]

- Address byte – where address 00 is for setting timeout (no other addresses valid at this time)

[7]

- Data byte – where data values of 00 – 7Fh (0 – 127 decimal) are valid values

[8]

- End of SysEx

Transmitter Specifications

Power 9 volt battery. PP3 type (also known as 6F22 or MN1604 or S-006P)

Power consumption Typically 55mA in normal use or 17mA when power saving

Battery life 4 – 5 hours with a full battery.

Transmit frequency 869.85MHz

MIDI In only

LED Indicates power on, low battery, power save & MIDI activity

Weight 285 grams

Dimensions 100 x 70 x 30 mm (not including antenna)

Non-volatile memory EEPROM (no back-up battery required)

Receiver Specifications

Power Input 9-12V DC 120mA, 2.1mm plug centre +ve (Mains adaptor supplied)

Receive frequency 869.85MHz

MIDI Out only

Display Four status LEDs indicate Power on (TX low batt), MIDI, RF-A & RF-B

Weight Receiver 850 grams – Power adaptor 300 grams

Dimensions 241 x 115 x 32 mm (not including antennas)

Non-volatile memory EEPROM (no back-up battery required)

WARRANTY

MidiStream

comes with a 12 month (from purchase date) back to base warranty, (i.e. customer must

arrange and pay for carriage to and from Kenton Electronics).

Brookfarm House, Station Road, South Wimbledon, London, SW19 2LP, UK

Tel: +44 (0)20 8544 9200 Fax: +44 (0)20 8544 9300

e-mail:[email protected] www.kentonuk.com

rev# 1116 e. & o. e.



December 2003