Shruthi-Synthesizer and my "WAVE 1"

#1

Hallo Mutable Instruments and User

I would like to formally express my thanks to the Olivier Gillert and his Shruthi-Team.

One year ago I started to develop my Stereo Synthesizer “Wave 1”. At the beginning of the 90s i want building a digital synthesizer.
My first project was a 8Bit soundsampler from DOEPFER Musikelektronik GmbH in germany. My next step was a digital
synthesizer on the basis of a digital sound chip SAM9203 from dream company. But I could not finish the project, because
my development tools was not not professional enough.

Now I have found many good ideas and tools for the construction of a synthesizer on the internet. Great help was the hardware
of opichenettes shruthi-synthesizers. My “WAVE 1” Synth is a Stereo-Version of an Hybrid-Synthesizer and have two analog Filtes (SSM2044) and
VCA-Chips (SSM2164). For sound editing is a small built-in touch-scree.

On yotube you can watch and listen to my first sound test. Youtube: http://www.youtube.com/watch?v=iwUUhr8rD48

My Synthi-Pic’s:

AVR_synth_10.jpg1296×972 557 KB

Synthi_Block_02a.jpg1588×2245 164 KB

Project-Site in german: http://www.cczwei-forum.de/cc2/thread.php?postid=79905#post79905

My Projekt-Site has a lot of information for musicelectronics and DIY synthesizers.

Geetings from old germany Rolf

PS: The new forum is very nice :slight_smile: But in my old posts are no more pictures. For this reason I have saved my old mutable posts from 4 years on my google cloud. Its free for everyone. Here is the link: https://drive.google.com/open?id=0BxbpDqwYdkvEMVBfd29JS1pTUk0

Say hello to a brand new forum!
#2

I’m guessing that you will be moving away from the devboard?
I would personally add 4 potentiometers or encoders for editing of on-screen parameters, since tactile feedback is nice, and more precise… Then again, that might just be me? :slight_smile:

#3

Hallo V’cent

I have one encode on my synth for change parameters. My idea is later, the sound of editing via midi controller.

Geetings Rolf

#4

Hallo shruthi-fans

I have make a Musikvideo for my AVR-Synth “WAVE 1”. Its new Stereo-Sound. The sound is only from synth stereo out without effect units.

Link: http://www.youtube.com/watch?v=B1hQOvVLosQ

SoundCloud: https://soundcloud.com/rolfdegen/avr-synthesizer-wave-1-stereo

Greetings Rolf

#5

Hallo shruthi users

I forgot the pictures of my synth in the post. Here they are…

In the next time i’m working on an sd-card interface for my synth.

Greetings from germany

#6

I have just one question : why wouldn’t you use 2nd order filters for PWM filtering?

#7

Hallo MicMicMan

The PWM-Frequency is verry high and you can’t listening on the audioout of my synth. In the new Software-Update for my Synth, i have change the pwm-Signal to 8Bit and 125KHz.

#8

Sounding good!

#9

As it has been discussed here before the Problem with high frequency PWM carriers may occur when redigitizin the signal. Try running your signal thru a (decent - not a Behringer…) compressor and you will see what i mean, it will compress even if theres no audible signal. On my old MX-8000 console i can just see those signals on the VU-Meter. Maybe you take a measurement and eventually think about filtering a bit more…

#10

The most sensitive point is the VCA CV (you’re already using a DAC for the oscillators, good!).

Here, you have a generous amount of filtering in place: 100k / 33n (cutoff at 48 Hz) ; vs a 125kHz carrier, so about 60dB of attenuation. However, I am unsure about the 100k / 33n combination for the RC filter - to me it looks like this would lead to excessive smoothing of the VCA modulation (and hence a lack of punch in the envelopes).

#11

Hallo

Thanks for your tips. I’ll think about it and make a few tests. I make scope pics from envelopesignal here.

See you and geeetings from germany

#12

Hallo shruthi-fans

I have test the envelope-time from my synth “WAVE-1” withe my scope (see pics).

Bild 1: Attack-Level = 0 / Attack-Level = 20
Bild 2: Attack-Level = 64

The shortest time for attack-phase is 4msec and for release-phase is 2msec.
The longest attack-time is 20sec with attack-level 127.
The interrupt-timer in my Xmega-Prozessor for ADSR-Signals is 1msec.

I think is good ?

Best greetings from germany

#13

Some people prefer snappier attacks for bass and percussive sounds.

#14

Hallo shruthi-users

I have looking for a simple and practical storage solution for the wave files and
Sound parameters in my AVR-Synth. I found the “ALFAT OEM Board” from
GHI Electronics (see pic 1).

Link: http://www.ghielectronics.com/catalog/product/337

By ALFAT board you can transfer datas on the XMEGA spi interface to SD & MMC cards and USB flash drives.
The maximum data transfer rate is up to 4 Mbytes per second specified.

ALFAT-concepts
A FAT file system for an SD card or USB stick requires a lot of resources on the microcontroller
in my synth. The SoC processor on the ALFAT module allows a fast and easy access storage via
UART, SPI or I2C interface.

Some features

  • Built-in 2-port USB Host controller.
  • FAT16 and FAT32 File system.
  • No limits on media size, file size or file/folder count.
  • LFN (Long File Name), licensed by Microsoft.
  • Friendly user interface through UART,SPI or I2C.
  • Programmable UART baud-rate.
  • Up to 8 simultaneous file access.
  • SD/SDHC card support, no 2GB limit. GHI electronics is an SD association member.
  • High speed 4-bit SD card interface.
  • Up to 4000 KBytes/sec file access speed SD cards/USB.
  • Single 3.3V power source.

Bild 1: ALFAT OEM Board
Bild 2: ALFAT concept

Greetings from germany

#15

@ pichenettes

Hallo pichenettes. Do you mean attack-time even shorter ?

#16

On Ambika I use ChaN’s FatFS code (I rolled my own FAT reader for the bootloader, though, because it has to fit in 4k) - it was very easy to adapt it to my project.

#17

Yes, shorter attacks, lower than 1ms ideally.

#18

Attack-Time: Thanks for your information. I think i can do that in my programmcode. How long is your longest Attack- and Release-Time.

#19

a synth should have envelopes so fast the click - if you are unshure take a google trip with the waldorf click

#20

Hallo shruthi users

I have change the adsr-circuit in my synth “WAVE 1”. My shortest attack-time is now < 1msec.