MacFi · Eight-message digital audio record/play system

Overview

The MacFi is a solid state digital audio record/play system with 8 randomly and instantly accessible messages, stored in non-volatile flash memory (FLASH EEPROM) without battery backup. Dynamic Message Length (DML) lets each message have its own duration, and a replacement message may differ in length from the original. Messages are recorded on the unit from a microphone or line source, and played locally from the top panel or remotely through parallel start inputs.

• MacFi 8, 8 messages, 8 minutes; MacFi 16, 8 messages, 16 minutes.
• ADPCM coding, 12 bit, 16 kHz sample rate; 100 Hz to 6.5 kHz frequency response, 60 dB dynamic range and signal to noise, THD below 1%.
• Built-in 4 W power amplifier for direct to speaker applications, plus a transformer isolated line output.
• No moving parts, for automatic unattended operation in harsh environmental or mobile conditions.

Installation

The MacFi mounts on a wall or a table (rubber feet included for table top use); an optional 1U rack mount adapter is available. Power comes from 12 VDC at 1 A, such as the optional MacFi-PS power pack (115 V, 50/60 Hz).

• Allow about 6″ in front of and 6″ above the unit for access to the controls and wiring.
• Keep the wiring at least 18″ away from power supplies and other equipment that generates electrical noise.
• Connect the audio inputs and outputs, then the control inputs and outputs.
• Set the DIP switches, connect and apply power, and test the operation.

Connections

• POWER: two terminal pluggable connector; terminal 1, +12 VDC at 1 A; terminal 2, ground.
• CONNECTOR 1 (12 position pluggable terminal strip): 1, common ground for all inputs; 2 to 9, START 1 to START 8, connect to common to play messages 1 to 8; 10, STOP, connect to common to stop playback or recording; 11 and 12, PLAY RELAY, Form A normally open contact, closed while playing.
• Control inputs are optically coupled and activate at 12 VDC, 5 mA; the play relay is a dry contact rated 1 A at 24 VDC, non-inductive load.
• CONNECTOR 2 (3 position terminal): 1, RECORD input, connect to common to enter record setup mode; 2 and 3, future use.
• AUDIO IN LEVEL: potentiometer for the record level, +4 dBm maximum input.
• AUDIO IN MIC: mono 1/8″ mini jack, up to 1.5 kΩ, for most consumer grade (low impedance) microphones.
• AUDIO IN LINE: mono RCA, 10 kΩ, for the unbalanced outputs of tape decks, CD players, DAT players and similar sources. The mic and line inputs cannot be used at the same time: disconnect the one not in use.
• AUDIO OUT LEVEL: potentiometer for the playback level, continuous from −∞ to +4 dBm.
• AUDIO OUT LINE: mono RCA, 600 Ω, transformer isolated, for the unbalanced inputs of most audio equipment.
• AUDIO OUT SPKR: bridged mono speaker output, 2 position terminal, 4 W into 8 Ω. Never reference either speaker terminal to ground: connect the speaker directly across the two terminals.

Configuration switches

An 8 position DIP switch sets the operation (up is OFF, down is ON). The system reads it only at power up; only Memory Protect takes effect without a restart. Number of plays and delay are global settings for all messages.

• Switches 1 and 2, number of plays per activation: OFF OFF, once; OFF ON, twice; ON OFF, three times; ON ON, four times.
• Switches 3 and 4, delay between plays: OFF OFF, 1 second; OFF ON, 5 seconds; ON OFF, 10 seconds; ON ON, 30 seconds.
• Switches 5 and 6, play method: OFF OFF, standard operation; OFF ON, play one sequence per closure; ON OFF, play while active; ON ON, re-trigger.
• Switch 7, Play Next: ON lets the START 8 input (Connector 1, terminal 9) play the next valid message sequence, starting with message 1 after power up; inputs START 1 to 7 are then disabled. All play methods are supported.
• Switch 8, Memory Protect: OFF enables recording; ON locks the message memory against accidental overwriting.

Playback modes

A message sequence is the message played the set number of times with the set delay between plays.

• Standard operation: a momentary contact closure plays one sequence of that message; a maintained closure repeats the sequence until it is released, and the current sequence is finished. Several maintained inputs play in the order they were activated (the lower input number wins a tie); a momentary closure released during a play is ignored.
• Play one sequence per closure: a maintained input plays the sequence only once; the input must be inactive for 100 ms before it is recognized again. Momentary activations are queued and played in the order received, up to 16 including the one playing, and a message may be queued more than once. STOP ends the current message and the next one in the queue then plays.
• Play while active: the message plays only while the input is held, and stops at once when it is released; a sustained input starts another sequence. No queuing.
• Re-trigger: a new activation, of another message or the same one, interrupts the message playing and starts the new one. A maintained activation plays the sequence once. No queuing.

Controls and indicators

The push buttons and LEDs are on the top of the unit, in a status section and a message section.

• POWER LED (green): off, no power; on, power on and system OK; blinking, system malfunction (see the memory test).
• OVERDRIVE (red): on when the recording input overdrives the system and the audio clips; set the input level just below overdrive.
• AUDIO SENSE (green): on when the input audio level is optimum; it is not an absolute indication of audio presence.
• RECORD (red): blinking in record setup mode; on while recording.
• RECORD SETUP button: enters and leaves record setup mode.
• START/STOP button: starts or stops the selected message, in record or play mode, and returns the system to idle.
• SELECT button: steps through the message positions; in play mode it skips empty locations.
• Message LEDs (green), with the RECORD LED: message LED blinking, message selected for play; on, message playing; all scanning, no messages recorded; blinking with RECORD blinking, the selected record location already holds a message; on with RECORD blinking, the location is empty; both on, recording in progress.

Recording messages

Locally, from the top panel:

• Press RECORD SETUP; the RECORD LED blinks.
• Press SELECT to choose the message location; its LED is solid if the location is empty and blinks if it holds a message.
• Monitor the source and check the OVERDRIVE LED to set the level, then cue the material.
• Press START/STOP and start the source; the message and RECORD LEDs stay on while recording.
• Press START/STOP to end the recording and leave record setup. Record setup times out after 1 minute of inactivity.
• Remotely, through the terminals: hold the RECORD input (Connector 2, terminal 1) active, so that the RECORD LED blinks; hold the START input of the message (Connector 1, terminals 2 to 9) active and start the source; release the START input to stop recording, then release the RECORD input to leave record mode.

Playing messages

• Locally: press SELECT to choose among the recorded messages (the LED blinks), press START/STOP to play, and press it again to stop. The selection times out after 1 minute of inactivity.
• Remotely: a momentary or maintained closure on a START input (Connector 1, terminals 2 to 9) plays that message with the set repeat and delay; a momentary closure on STOP (terminal 10) stops it, or the system returns to idle at the end.
• Inputs for empty or corrupt message locations are ignored.
• The play relay stays closed for the whole play sequence and opens for about 100 ms between queued or repeated sequences.

Memory test and erasing messages

• Memory test, to clear the recorded messages or to test the memory: remove power, hold RECORD SETUP while power is restored until the RECORD indicator stays on, then release it. The message LEDs cycle while the audio memory is checked, up to 15 minutes on the MacFi 8 and 30 minutes on the MacFi 16; the unit resumes normal operation when the RECORD indicator goes off. Removing and reapplying power skips the test.
• To erase a single message, record less than 250 ms into its location.

Troubleshooting

• POWER LED blinking → system malfunction; run the memory test.
• Recording does not start → check that Memory Protect (switch 8) is OFF.
• Microphone not recorded → disconnect the line input; mic and line cannot be used together.
• OVERDRIVE LED on, distorted recording → turn down the AUDIO IN LEVEL.
• A changed DIP switch has no effect → remove and reapply power; the switches are read only at power up.