TheSlowGrowth Posted May 6, 2014 Report Posted May 6, 2014 Hi! I'm looking for a digitally controllable multi fx board to fit into a synth. I'm looking for something with: at least two independent fx channels mono in, stereo out per channel high quality reverb, delay, + some more effects completely controllable via MIDI or any other protocol that can be connected to a MIDIbox small form factor I could go for a general purpose rack mounted fx processor and remove the case+ui. But it seems impossible to find something that can be completely controlled without touching its user interface. Any ideas? Johannes Quote
EsotericLabs Posted May 6, 2014 Report Posted May 6, 2014 Check http://dream.fr/ they have DSP IC's, including FX processors. Why not take a look? Quote
Shuriken Posted May 6, 2014 Report Posted May 6, 2014 A couple of years ago Elektor developed a board around the SpinSemi FV1. That is controllable via MIDI. But not sure if you can do it without touch the UI. The ideal situation would be a FX chip which is controlled through MIOS. Quote
TheSlowGrowth Posted May 6, 2014 Author Report Posted May 6, 2014 SpinSemi FV1 looks great, but also very limited - I see no way of controlling this thing digitally. What a pity... dream.fr looks like a good choice. The SAM3703 costs about 9€ and offers all I could ever need. Cool! Seems like I can simply connect an I2S codec and i'm ready go go. I'm just afraid of the complexity... Thanks for your suggestions! I'll dive into that dream.fr stuff and what I can do with it Quote
EsotericLabs Posted May 6, 2014 Report Posted May 6, 2014 (edited) They have example applications and evaluation /development boards http://dream.fr/pdf/Serie3000/Boards_Datasheets/3703FX-EK.pdf I wanted to take a closer look too, especially at the guitar amp stuff with the 3703 or the 3416. But I also dreamed away building a midibox controlled mixer with the 3816. I have toyed around with one of their GM sound board chips, see Most of the controlling could be implemented with MBNG I think. Edited May 6, 2014 by EsotericLabs Quote
Shuriken Posted May 7, 2014 Report Posted May 7, 2014 Don't forget that these are just DSP chips. So without a firmware you don't have anything. It looks like the different eval boards include firmware, but that will probably be reflected in the price. Quote
EsotericLabs Posted May 7, 2014 Report Posted May 7, 2014 (edited) Yes the boardz need warez. I 've asked them for price info. Edited May 8, 2014 by EsotericLabs Quote
TheSlowGrowth Posted May 9, 2014 Author Report Posted May 9, 2014 I'm afraid, this is not gonna be cheap... Quote
EsotericLabs Posted May 9, 2014 Report Posted May 9, 2014 We'll see. Price info should be free. Quote
TheSlowGrowth Posted May 14, 2014 Author Report Posted May 14, 2014 Just found this: http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=RA-FX1V Just like the SPIN chip it's not controllable digitally... but it seems bo offer higher quality at a price of 21€ Quote
Shuriken Posted May 14, 2014 Report Posted May 14, 2014 The Spin Semi chip is perfectly controllable through an MCU (see this design). Not sure why you conclude it is higher quality. Both have similar specs if not the same (i couldn't find any difference reading both datasheets). I did not mention this before, but it comes with free IDE. So you can program your own effects. Your module is ofcourse plug and play. So if you want a quick fix, that's the way to go. Quote
niklasni1 Posted May 14, 2014 Report Posted May 14, 2014 Are you sure that RA board isn't based on the Spin chip? Quote
niklasni1 Posted May 14, 2014 Report Posted May 14, 2014 (edited) As for the Spin, it only has three inputs for control, and they're all analogue. You can control the selected program from an MCU, but not advanced digital control of parameters. (Unless you emulate an external ROM for it and change the code on the fly, I don't know how hard that'd be to get to work?) Edited May 14, 2014 by niklasni1 Quote
EsotericLabs Posted May 15, 2014 Report Posted May 15, 2014 Great find! Profusion has also the dream chips on evaluation boards. Overview and Price info here: http://www.profusionplc.com/pro/gex/prodGen.html?prdtyp=Evaluation%20boards Quote
TheSlowGrowth Posted May 18, 2014 Author Report Posted May 18, 2014 @niklasni1: You're right, and that's the problem. Analog outputs are relatively expensive and the chip digitalizes its analog inputs anyway. So IMHO that the least elegant way of controlling the Spin. Unfortunately the problem is the same for the RA-FX1V. @shuriken: I don't know if the RA-FX1V is higher quality than the Spin... But it offers many different reverb algorithms - whereas the spin only has two distinct reverbs. Also, the RA-FX1V has 16 programs and the Spin has only 7. Still, that's no proof of higher quality, but it fits my usecase a lot better. And it makes me think its better.... Actually you're right, they might even offer the same quality.... Okay, you can programm your own algorithms for the Spin. But I have absolutely no clue on programming good reverbs - and reverbs are the most important fx in a synth (at least for me). The RA-FX1V has so many of them, I have better chances finding a usefull one among them. What really bothers me, is that none of the above solutions offer a synced delay. Quote
niklasni1 Posted May 18, 2014 Report Posted May 18, 2014 There's no audio in module for MIDIBox yet, of course, but sync'd delay should be a piece of piss on a STM32F4 board.. Quote
niklasni1 Posted May 18, 2014 Report Posted May 18, 2014 There's no audio in module for MIDIBox yet, of course, but sync'd delay should be a piece of piss on a STM32F4 board.. Quote
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