Werner, I would look at an OKI chip (MSM5202) that does 4 bit ADPCM encoded speech. at 8 khz it sounds really good. and don't forget that's only 4 bits so each byte is 2 samples. record your message with a PC into a WAV file and OKI has software that will translate that to 4 bit ADPCM. Stuff that file in EPROM and it would be easy for the PIC to feed it to the OKI chip at 8khz. the OKI chip provides an interrupt to ask for another sample. I did a similar design many years ago.... good luck. Jason Wolfson Lipidex Corp -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Werner Terreblanche Sent: Monday, April 20, 1998 6:35 AM To: PICLIST@MITVMA.MIT.EDU Subject: Generating Digital Speech cheaply I would like to hear some opinions from other people that have already done the same thing I plan to do.... Basically I want to make a very cheap voice playback device capable of playing back a fixed set number of short pre-recorded voice messages. I know you get special IC's and CODECS that does exactly this, but they are still slightly too expensive for what I had in mind. EPROM IC's are very inexpensive these days, and I thought that maybe if store my messages as raw digitized speech on a large EPROM and play it back through a resistor ladder network A/D and filter, I would be able to regenerate speech messages at a relatively low cost. If I then use a PIC to address the EPROM and add a serial interface to it, this could become a very cheap speech messaging system that is addressable via the serial bus from my target microcontroller. Now, my questions are this: 1. Is it a feasible way of doing this? 2. What sampling rate would I need? (I was thinking 8KHz @ 8 bits resolution) Is this good enough? 3. Has anybody perhaps done something like this already? Was the sound reasonably clear? One final question.... Some time ago, someone on the Piclist mentioned a stand-alone text-to-speech synthesizer available for as low a cost as $49.95. I can not remember the details anymore. Do anybody where I can buy one of these? I made a search on the web, but all I could come up with is a device from RC systems http://members.aol.com/rcsys which costs about $150, and is thus a bit too expensive for what I had in mind. Have anybody reading this ever used these text-to-speech modules and do they work well? Rgds Werner -- Werner Terreblanche Tel : (021) 7102251 (office hours)