AP-16+ Q&A

[JonnyMac]

Q: Why the +?

A: Well, we actually created a product called the AP-16 but we so unhappy with it that we scrapped it and started over.  The problem was with the ISD1700 chip that has issues not acknowledged by the manufacturer (until the "evil" JonnyMac had a stern conversation with some of their engineers; then they came clean with problems they didn't think would affect anyone).  

Also, with the EOL of the SX chip we decided to go with the Propeller.  Doing that allowed us to move directly to stereo WAV files – we think that's a big "plus."  By playing WAV files from an SD card we moved from four minutes of audio (ISD17240) to virtually unlimited, and at much better quality.


Q: Why WAV?

A: WAVs are easy to produce and don't have any licensing issues.  We could have gone MP3, but that would have required another chip on the board (MP3 decoder) which only adds to cost.  Remember that the MP3 format was created several years ago when media (compact flash and SD cards) had limited storage space and were very expensive – things have flipped the other way now; media is huge and very inexpensive, so file size is really not an issue.

Another thing: MP3s are encoded and have to be decoded before playing; this can create a delay when starting the file – you won't see this with a WAV file.  Yes, it has a header, too, but it's very small (44 bytes) there is no delay.  When you say, "Go!" the AP-16+ does just that.

Note that for best performance we do require the WAV file to be PCM format, 16-bit, stereo.  If you file doesn't conform to standard this you can easily convert it with Audacity or any other audio editing program.


Q: Can I have a "backgound" file that plays when nothing else is happening?

A: Yes.  Simply put a file called AMBIENT.WAV onto your SD card and enable the background looping by setting the Ambient Loop option switch to ON.


Q: What if I want to change the background audio from time-to-time?

A: You can only do this if you're using an external prop controller (e.g., Prop-1 or Prop-2).  To put a file into infinite loop you would use a Play command with zero (0) loops.  In the Prop-1 you might do something like this:

 SEROUT Sio, Baud, ("AP16", %00, "PW", "WIND", 13, 0)

This will play the file, WIND.WAV, until an "X" command or another play command.  If you play another audio file later you'll need to run that above line again to restart the background.  You may want to put this into a subroutine so that it can be called easily.


Q: How many files can I play?

A: In manual mode: 24 (SFX00 - SFX15, AUX01 - AUX08); in remote control mode there is no limit (using the "PW" command).


Q: What kind of manual inputs are supported?

A: Dry-contact, optically-isolated 12-24VDC, PIR, and an on-board pushbutton for SFX files.  For AUX files the auxiliary header supports up to eight dry-contract inputs.


Q: What about volume controls?

A: Each channel has its own (maximum) volume potentiometer.  If you're using a controller you can set the volume in software using the "L" (levels) command.


Q: Can I change the playback speed/pitch?

A: With a controller, yes.  The AP-16+ has a "S" (speed) command that lets you set the playback speed from 50% to 200%.  Note that the maximum sample rate is 44.1kHz, so files with the setting can only be played more slowly.  If you want to be able to change the playback in both directions, re-sample the file to 22kHz (easy with Audacity).


Q: Can I stop audio that's playing?

A: Yes.  In manual mode you can stop any file by connecting a normally-open button between the 3V3 and IN8 terminals, and setting the audio stop enable (EN) option switch to on.  If you're using an controller the "X" command will stop the audio and reset everything.


Q: Can I use the standard 12V, 1A power supply that you carry?

A: Yes, BUT.... that supply is only capable of delivering 12W so you cannot assume to get 40W of audio power out of the AP-16+ when using it.  What you'll find is that if you turn the volume up to high (past about 20%) the 12W power supply will not be able to keep up with the demand for power and the sound will become distorted.

Note that we do have a part # (31317) that includes the AP-16+ and a 60W power supply.  The reason we don't sell this supply separately is that we don't want to be selling low-cost (low-margin) power supplies to folks that normally don't purchase other EFX-TEK products.  We charge $30 for the 60W power supply; you'd normally pay 2x to 3x that for a similar supply (e.g., for laptop computers).


Q: When I power up the status LED flashes red -- what's up?

A: On power up the AP-16+ takes inventory of the files it uses for stand-alone mode: ambient.wav, sfx00.wav - sfx15.wav, and aux01.wav - aux08.wav.  If none of these files is present or is not correctly formatted, the AP-16+ will not see them.  For review, the correct format for WAV files on the AP-16+ is: 16-bit, stereo, PCM-encoded WAV files with a sample rate of 44.1kHz or lower.  If you have files on your SD card that the AP-16+ is ignoring we suggest you open them in Audacity, re-sample (if necessary) and re-save with the correct settings.  It only takes a few seconds per file.


Q: Can I play mono files?

A: Yes.  As of version 1.7 the AP-16+ will play both stereo and mono files.  The files must still be 16-bit, PCM encoded.


Q: I'm not using the relay -- is there any way to deactivate it so that it doesn't "click" when a file plays?

A: Yes.  As of version 1.7 you can disable the relay activation by adding the file NORELAY.TXT to the SD card that holds your audio files.  The contents of the file do not matter; just the presence or absence of it.


Q: Can I control the relay through the serial link?

A: Yes, as of version 1.7 the AP-16+ has an "R" command for activating and deactivating the relay.  Since this is a user-controlled activity, the presence or absence of NORELAY.TXT does not matter.


Q: Why doesn't my wonderful brand SD card work?

A: All SD cards are not created equal.  They are, in fact, "smart" devices that have onboard intelligence that the AP-16+ has to interact with.  As of version 1.7 the playback buffer for the SD card has been quadrupled and this seems to help finicky SD cards play normally.  Do keep in mind that the AP-16+ does not have the same resources (processing power and memory) as your PC, so a card that works great on your PC may still not cooperate with the AP-16+.


Q: What happens if someone takes the SD card out of my AP-16+ that's embedded in a prop or display -- how will I know.

A: In version 1.7 we added an audible alert (beep-beep-beep, every 5 seconds) at power up if there is no SD card in the AP-16+.

[migman]

I wanted to know if the AP-16's that were delivered after Aug 30, 2010  (i.e. those that were shipped just before halloween) have the latest version of firmware loaded?  With an SX there is no way to display the response from a version command with just a blitz programming conection.  I guess I could just program up a prop 1 and use it to check or just download the latest version and program the AP-16 just to be sure!

[JonnyMac]

They should have 1.03 but you could guarantee it by dropping the file (AP16.PGM -- available as a download on the AP-16+ product page) onto an SD card and letting the update run its course -- it only takes about 15 seconds.

[migman]

Does the 1.7 firmware update include everything listed in the previous version numbers even if they were not released to the public i.e. +1.6 and +1.5?

[JonnyMac]

Does the 1.7 firmware update include everything listed in the previous version numbers even if they were not released to the public i.e. +1.6 and +1.5? 

Yes, of course. Version 1.7 includes all changes since the initial release.  Those versions that we didn't release (which mostly happened within the last couple weeks, we're internal and for testing discrete changes.

[haunter45]

I have a ap 16+ and Im curious if I have different audio files on the sd card can I have them playing at the same time but from different speakers

[JonnyMac]

No. The AP-16+ can only play one file at a time. This is why we make them "networkable" -- it allows a controller (like the Prop-1, Prop-2, or HC-8+) to control multiple sound FX at the same time.

[JackMan]

I have a ap 16+ and Im curious if I have different audio files on the sd card can I have them playing at the same time but from different speakers

Like Jon said, can't be done with one AP-16+ but there is a little trick you can do to play 2 different sound tracks at the same time. Use an audio editor to create a single sound file with different audio on the left and right channels. Use the appropriate left and right channel outputs of the AP-16+ to your different speakers. When the file plays you'll get 2 sound tracks playing at the same time but you'll only hear one from each channel. Of course the best thing is to use two AP-16+'s but this can work for certain situations.