<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">There isn’t much at the low-end of the DSP market, so your options are limited.<div class=""><br class=""></div><div class="">There’s the FXCore, which can deal with 4 ins/4 outs, but needs external codecs (but that lets you choose for best quality or lowest price)</div><div class=""><br class=""></div><div class=""><a href="http://www.experimentalnoize.com/product_FXCore.php" class="">http://www.experimentalnoize.com/product_FXCore.php</a></div><div class=""><br class=""></div><div class="">Otherwise, you might be best moving to a bigger, faster chip and then expecting the one device to process 16 channels of audio for you. You’d still need a multi-channel codec, and the hardware is going to be all throughly modern and SMD-tiny!</div><div class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 21 Mar 2021, at 14:34, cheater cheater <<a href="mailto:cheater00social@gmail.com" class="">cheater00social@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">It's 2-4x too expensive, but I'll check the youtube demos anyways -<br class="">thanks a lot.<br class=""><br class="">On Sun, Mar 21, 2021 at 3:23 PM Tom Wiltshire <<a href="mailto:tom@electricdruid.net" class="">tom@electricdruid.net</a>> wrote:<br class=""><blockquote type="cite" class=""><br class="">I don’t know that it fits your definition of cheap in small volumes, but the Spin FV-1 chip is about your best option, I’d say. It’s a simple-to-use almost all-in-one option and there are loads of good reverb algorithms for it freely available.<br class=""><br class="">The standard application uses a cheap watch crystal (so 32KHz sampling) but you can run the chip faster if you need a little bit more hi-fi. Honestly, I doubt this is necessary for reverb. The high end is absorbed most quickly and hardly appears in any reverb signal. But it’s easy to do if required. I think the chip is specced up to 50KHz or so, and people have overclocked them faster than that - Spin left themselves a good safety margin.<br class=""><br class="">The algorithms are stored on an external EEPROM, but there are also 8 internal programs, including several reverbs, so if you use those you can do without the external EEPROM, at which point it really is a one-chip solution.<br class=""><br class="">Check out a few FV-1 effects pedals on Youtube and see what you think.<br class=""><br class="">HTH,<br class="">Tom<br class=""><br class=""><blockquote type="cite" class="">On 21 Mar 2021, at 13:19, cheater cheater <<a href="mailto:cheater00social@gmail.com" class="">cheater00social@gmail.com</a>> wrote:<br class=""><br class="">I have been thinking recently about whether it would be feasible to<br class="">have a simple reverb of some sort per voice, and so I wonder if anyone<br class="">had any suggestions on a cheap algorithm that could be executed on<br class="">inexpensive chips.<br class=""><br class="">what I need from the reverb: exponential decay of ~0.5 second, flat<br class="">frequency spectrum @ 22 Hz...22 kHz<br class=""><br class="">instrument: 16-voice<br class=""><br class="">architecture: vcos -> filters -> vca1 -> possibly vca2 (all stages analog)<br class=""><br class="">I'd like to be able to insert reverb after the filter but before the last vca:<br class=""><br class="">vcos -> filters -> vca1 -> rev -> vca2<br class=""><br class="">or possibly after the vco:<br class=""><br class="">vcos -> rev -> filters -> vca<br class=""><br class="">or after the filter:<br class=""><br class="">vcos -> filters -> rev -> vca<br class=""><br class="">or even:<br class=""><br class="">vcos -> rev1 -> filters -> rev2 -> vca -> rev3 -> vca2 -> rev4<br class=""><br class="">The reverb is meant to only "sweeten up" the sound by giving filter<br class="">sweeps, transients, and vco sweeps some more substance in the time<br class="">domain. I think this sort of thing could easily add a unique sound to<br class="">the synthesizer. I know some of you will mention the DSI Evolver, but<br class="">honestly I did not think that the digital part in that synth was of<br class="">high enough quality. So what I'm looking for is an inexpensive "hi fi"<br class="">reverb.<br class=""><br class="">The considerations are either:<br class="">A) a single chip per voice/stage which only processes one stage in one<br class="">voice. this chip would have to have high audio quality AD/DA, work<br class="">without a lot of additional circuitry, just enough processing power to<br class="">perform the reverb, and be relatively inexpensive (up to ~5 per chip<br class="">at low volumes)<br class="">B) one global chip with a bunch of AD/DA. this chip would need to be<br class="">able to read from 64 AD and write to 64 DA, each at 16 bit.<br class=""><br class="">personally I prefer A because 1. it does not carry a bunch of digital<br class="">stuff around an otherwise analog board which can be a royal pain and<br class="">2. drifting clocks (or ones shifted on purpose) will add variety to<br class="">the sound. So those two kind of kill B for me.<br class=""><br class="">What sort of chip would you all suggest for version A?<br class=""><br class="">What algorithm would you suggest to run on it?<br class=""><br class="">Thanks.<br class="">_______________________________________________<br class="">Synth-diy mailing list<br class=""><a href="mailto:Synth-diy@synth-diy.org" class="">Synth-diy@synth-diy.org</a><br class="">http://synth-diy.org/mailman/listinfo/synth-diy<br class="">Selling or trading? Use marketplace@synth-diy.org<br class=""></blockquote><br class=""></blockquote></div></div></blockquote></div><br class=""></div></body></html>