Hi all,

Heres a synth I've put together using many different sources. I created this as part of a uni project. It still needs a lot of work on it, and is quite messy in some places.

As it is, I would like some user feedback. Would you be kind enough to have a play with it for 5mins and provide me with some feedback.

About the synth:

Oscillators - each Osc has four saw waves each with a pitch decrepancy of 2.5 cents to cause a slight phasing, each voice is fixed at a different postion within the stereo field.

Envelope - standard ADSR, still has problems: the release is being triggered every time it receives a velocity of 0, so when playing in a legato fashion it can cause glitches or stuttering.

State Variable Filter - uses [svf~]. Toggle selection of filters enable you to layer several different types. Also uses an LFO to modulate signal. LFO Stereo Offset adds a delay of up to 1.5 seconds to the right outlet.

Modulated Band Pass Filter - uses [bp~]. also uses [random] and [metro] to modulate the frequency cutoff.

Sub Bass Oscillator - This is meant to be a sub harmonic synthesiser. For the purposes of a prototype, this is outputting a two sine waves, one fixed at 55hz the other controlled by user input.

Velocity Controlled Filter - a low pass filter controlled by velocity to differentiate between soft and hard notes.

Feedback:
Please can you consider the following points:
Your initial thoughts, ergonomics and user ability, layout of the GUI and quality of the sound outputted.

Would you find it a useful tool in your compostions?
What would you like to see improved in the future?

Future Developments:
Here are a few ideas I would like to implement in future development.

Saving Presets -
Currently a user has to note down any settings and manually recall them; this can be inaccurate and prone to human error. An ideal solution would be to have a feature where users could save their presets of sounds created and digitally recall them.

Portamento-
This would give the user control over the amount of time in which note pitches, crossover or glide between each other.

Pitch discrepancy
Another idea to give voices further separation would be to constantly modulate the pitch discrepancy within a very small and limited range. This would be governed by a slow oscillating sine wave. Experiments would have to be carried out to find if a single oscillator, modulating all the voices pitch discrepancies in order to keep all the voices synchronised. Would this be the best option or would it be better to have separate non synchronised oscillators at various speeds?

Routing Matrix-
This would be an easy-to-use interface as part of the Graphical User Interface (GUI) to enable the user to choose in what order the signal path flows to each module, also giving options to run signal paths through modules in series or in parallel.

Frequency Crossover-
Primarily this module would give the user choice of several variable frequency bands and their type of output, ie; mono or stereo. An interesting feature to add would be to tie this into the proposed routing matrix module to allow the routing of different frequency bands to different destinations. This would be useful in routing different frequencies bands to certain effect modules.

Stereo widening-
This would place the sound by varying degrees into the negative phase to simulate a widening of the sound within the stereo field. The user would control the amount via a slider or rotary in the GUI. This would be connected to or use features from the proposed frequency crossover module to control which band of frequencies were affected, ie; it would be useful to keep the sub bass frequencies in mono and only widen the mid and high frequencies.

Equalisation-
This module would be a five band equaliser featuring a High Pass and Low Pass filter along with three variable bell equalisers. It would also be useful to tie this in with the proposed Routing Matrix so that the user could insert this into different destinations within the signal path.

Effects
There is a long list of useful effects that could be implemented into this project, including: Reverb, Delay with tempo sync options, Unison, and Bit Crusher. All would be separate modules and would give the user several parameters to control the effected signal.

Creative Waveforms.
This uses arrays to allow the user to draw in different shapes as waveforms for each main oscillator. This feature would give the user an extra layer of creative freedom, however it could cause problems so would have to include some preset waveforms for the user to initialise, such as sine, square and sawtooth waves. This would also make an interesting addition as a means of controlling the LFO oscillation.

The project is attached below. Please note: the Synthgui.pd file is the main window.

Greatly appreciated, Student Sound Designer.

http://www.pdpatchrepo.info/hurleur/PD_SYNTH_FINAL_SUBMISSION_(1).zip

here's a little pattern generator. If you add something like this, it makes things more immediate.

also might be a good idea to set your volume at a reasonable level to start with, and i think the filter bypass should be switched off at first too.

I always loadbang DSP as well, but others disagree with me on that.

anyway, the more you can do to make it work 'out of the box' without people having to switch things on and off, the better.

my quick impressions:

pd-wise:

you're quite organized and tidy which is nice to see. patching is logical and easy to follow.
one thing I'd advise against though, is using unnecessary GUI objects inside subpatches. You have quite a few toggles and numberboxes, ect which are not used in the main GUI. it's best to get rid of them, as they waste computer resources.
Also, something to consider, is that you're using a few non-vanilla externals ([spigot~], [overdrive~] etc...), which could be quite easily replaced by vanilla pd objects. If you end up doing pd to be used in commercial projects, this is quite vital, as the licensing and loading of externals is a lot trickier than vanilla pd, which is under a very free license (BSD)

synth-wise:

the layered phasor~s give quite a nice thick sound. pretty cool. Also i quite liked the random modulated bandpass filter, which reminded me of the trigger vcf mod on my old jupiter 4.
the overdrive adds a bit of punch too, which is nice.
oh, and the velocity controlled filter, separate to the main filter, is a cool idea. works pretty well.

one thing that's missing is the ability to modulate the main filter with the envelope. that is pretty much THE main character of most old analogue synths, and it really does liven things up. You already have an envelope and a filter, so it's just a simple [send] [receive] pair and a slider to control the depth, and you're sorted.

also, the subbass seems to need a bit of work. it was quite clicky for me, and i'm not sure why you have a fixed wave at 55hz. not sure if that's the best idea. hmm...

one other control i'd add, would be a slider to control the slew time of the modulated bandpass filter. also, if you could retrigger it from noteon messages, i think it might be a bit more usable.

anyway mate, nice work, and keep at it. there's some good ideas in there.

oh, and the way you're building stereo into the synth from the ground up is really cool too.

http://www.pdpatchrepo.info/hurleur/patgen.pd

Yeah, its fun to hack that thing!
I'am going to follow your progress.