MacFi-mp · MP3 digital audio record/play system, 99 messages

Overview

The MacFi-mp is an MP3 digital audio record/play system with up to 99 messages and 40 minutes of audio (MacFi-mp 40), stored in non-volatile flash memory (FLASH EPROM, 32 MB) 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. All 99 messages can be recorded and played from the unit’s top panel; the first 8 also have remote start inputs on terminals.

• Records MPEG 1 Layer 3 (MP3), variable bit rate; 50 Hz to 15 kHz, 80 dB dynamic range and signal to noise, THD below 0.5% at 1 kHz, typical.
• Built-in 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-mp mounts on a wall or a table (rubber feet included for table top use); an optional 1U rack mount adapter is available. It needs 12 VDC, 1 A with the power amplifier in use or 250 mA without, such as the optional power pack (115 V, 50/60 Hz) on a standard, non-switched outlet.

• 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.
• Set the DIP switches, then connect the audio inputs and outputs and the control inputs and outputs.
• Connect and apply power, and test the operation. After power up the unit runs a self test (about 2 seconds) and goes idle.

Connections

• POWER: two terminal pluggable connector; terminal 1, +12 VDC at 1 A; terminal 2, ground. The green POWER LED is on when power is supplied and the system is OK.
• 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 contact that closes while playing.
• Inputs are activated by a mechanical contact or an open collector driver, 3 mA activation current; 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 on Connector 1 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, low impedance, for most consumer grade 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 or 6 W into 4 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 settings are read only at power up; to change them, disconnect power, set the switches and reapply power. Number of plays and pause are global settings for all messages started through the remote activation connector.

• 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, pause 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 pause between plays.

• Standard operation: a momentary contact closure on a start input 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 sequences 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. With several inputs held, only the active message of the highest priority plays. 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; simultaneous activations play only the lower numbered message of the highest priority. No queuing.

Controls and indicators

The push buttons, LEDs and a two digit, seven segment message number and status display are on the top of the unit.

• OVERDRIVE (red): on when the recording input overdrives the system and the audio clips; reduce the AUDIO IN LEVEL and set it just below overdrive.
• AUDIO SENSE (green): on when a signal is present at an optimum level; off when the audio is low or absent. 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 numbers; in play mode it skips empty locations. Holding it steps by tens, to move quickly through the 99 messages.
• Message display: 1 to 99, message selected, playing or recording; all segments cycling, no messages to select; both decimal points blinking, the location already holds a message; FC, bad block memory test running.

Recording messages

Locally, from the top panel:

• Press RECORD SETUP; the RECORD LED blinks.
• Press SELECT to choose the message location on the display; both decimal points blink if it already holds a message.
• Listen to the source through the audio output and check the AUDIO SENSE and OVERDRIVE LEDs to set the level.
• Press START/STOP and start the source; the message number and RECORD LED stay on while recording.
• Press START/STOP to end the recording. Record setup times out after 1 minute of inactivity.
• Remotely, for messages 1 to 8: hold the RECORD input (Connector 2, terminal 1) to common, so that the RECORD LED blinks; hold the START input of the message (Connector 1, terminals 2 to 9) to common 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 default is the first valid location), press START/STOP to play, and press it again to stop. The selection times out after 1 minute of inactivity.
• Remotely, for messages 1 to 8: a momentary or maintained closure between a START input (Connector 1, terminals 2 to 9) and common plays that message with the set repeat and pause, its number on the display; 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 clear/test, to clear the recorded messages or to test the memory for bad blocks: remove power, hold RECORD SETUP while power is restored until the RECORD indicator stays on, then release it. The display reads FC during the check, up to 20 minutes on the MacFi-mp 40; 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 1 second into its location.

Troubleshooting

• 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.
• Display cycles through all segments when SELECT is pressed → no messages are recorded.
• A changed DIP switch has no effect → remove and reapply power; the switches are read only at power up.