Posted by zdw 9/13/2025
https://www.w3.org/TR/audio-eq-cookbook/
By chaining various combinations of EQ and non-linear distortion (lots of ways to implement this, probably involving more FMAs) and you can build very good simulations of common analog synth signal paths.
Note that gsliepen's example sample rate of 96 kHz is perfectly reasonable in this context; it's more than you need to exceed the limits of human hearing, but it's common to oversample your signal for processing to avoid problems with aliasing.
Now, processors are so fast and cheap, that the need for dsp is way down. I personally ported the firmware for a popular pedal where the chip used was no longer available at quantity, and while it was tricky to get the same performance on a dual core 240mhz processor with floating point coprocessor, as the 96Mhz processor it was replacing, I just had so much compute, that I was able to port all but the gnarliest simultaneous effects on a chip that cost $6 cheaper but also came with enough ram to not need that $3 component either. And I can tell you, saving $9 dollars off a BOM means the product can retail at least $50 cheaper in an industry where volume matters a lot (no pun intended).
We have passed the inflection point where dsp chips are generally not worth the cost in most audio equipment. I’m not sure I’d use a raspberry pi, their reliability is not what I’d want in my products, but a similar single board computer? maybe. I’m not sure where linux realtime kernals are at the moment, ignoring the added complexity of a full linux running to process audio, audio requires hard deadlines. You will hear pops and other artifacts if you miss these deadlines, and buffering audio is also not something you can do for long, artists can feel delays in the ms. But, a single board computer running at ghz speed, gives an awful lot of compute so long as the OS can gaurantee your audio thread won’t get starved.
I work in the field and clunky, shit software is the norm. In particular, radiology information systems (RIS) just kill me. How are they so crap?
1. Accurately dose the required ingredients based on a setting selected.
2. Do so in a repeatable manner. 5mg is microscopic and likely well beyond the margin of error for a small dose pump. So you'll need to get creative in how you manage your product dosages. Perhaps a "reel" of pre-measured 1mg doses? You say it's not for Nicotine, so I assume it's for harder drugs. What will the risk of a double digit % overshoot be?
3. Be small enough to fit into a handheld vape module.
People also use this to make unique pedals.
[Note: and the amount of tutorial videos on YouTube is huge.]
It's not just iOS.
Zynthian and Monome provide an AMAZING ecosystem for audio exploration. If you haven't checked that out as well, here's the links:
That said - I could easily just get another iPad, throw away the room full of synths, wire up my iPads and the Zynthian and Monome systems, and be quite satisfied.
And it doesn't hurt that when need more power/features you can upgrade to its big brother Logic Pro X which offers a very similar interface.
What complications do you run into outside of garage band, or you imagine you would run into?
I have at various points in my life used Garage Band, Logic, or various Linux software.
1. Mac Core Audio (Works out of box)
2. Windows ASIO (ASIO4ALL or just plugin a Scarlett/MOTU audio interface)
3. Linux Pipewire
Alchemy in GarageBand has many presets with adjustable filter envelopes (sometimes multiple) and volume envelopes, so it can work as a subtractive synth stand-in. However since it's based on Alchemy Player you don't seem to get the full patch creation power of Alchemy in Logic Pro.
GarageBand's "synth" (named) presets that I've tried appear to be subtractive, and sound great, but seem to limit user controls to filter cutoff and a single envelope for both volume and filter (possibly with configurable envelope amount). Some presets have slightly different controls though (for example an FM amount.)
Fortunately there are lots of great AUs, including free ones, for traditional virtual analog subtractive synthesis (and FM, and everything else.)
The iPad is a great choice for music - you get the variety of hardware synths with none of the annoying setup (power, midi, audio routing), at a cheaper price, but it still feels more immersive than sitting at a desktop PC and a daw.
There are things you can do to make computers more suitable for this stuff but it gets expensive fast and less convenient quickly. Toughbooks are tempting, but expensive, rackmount computer can be managed for not much and keeps the computer safe in its rack but now you more and bigger stuff to haul. Taking a disposable approach with rpi or the like is tempting but not exactly ideal. Computers/tablets are great and have their uses but are not a replacement for hardware yet.
The big problem for me with all things touch screen is that they get confused by water on the screen, which is an issue when it is hot and you are sweating or on a stage with bright lights cooking you. Not an issue if you just want to tap out beats but a serious headache if you want to adjust parameters. Connectors on tablets are also an issue, USB is not a very secure connection and the wireless options are not great. Give me a tablet with a plastic screen, 1/4" ins/outs, can run PureData and will not get confused by water on the screen and I will probably give up my hardware.
On the other hand, my Blofeld had wonky unresponsive knobs after just a couple of months, not that they were very good at the first place, who thought having knobs with no tactile feeling of grip was good idea?!
Personally the biggest win for actual hardware is that it's just more fun to play and use. I've tried various music apps for mobile/tablets and while it's fun for some minutes, that's pretty much it. But then I feel the same with DAWs, it's just not as fun as playing with an hardware drum machine + synth + sampler all hooked together.
No joke? I was sure it was a hardware issue, but guess I should give that a look, still have my Blofeld around here somewhere, thanks for sharing the "news" :)
> love the detentless encoders
I have no issues with them being detentless, makes a lot of sense. What I do have issues with, is using the smoothest material they could find for the knobs instead of something you can "grip", sometimes it just slipped between my fingers when trying to turn them, unless I make my fingers slightly humid first.
I get why you dislike the knobs, but they don't bother me. Many dislike them and I have seen various fixes like shrink tubing, tape and rubber bands as well as just replacing them. I just learned to pinch the knob a little tighter. Skipping their traditional coating on the knobs was probably one of the corners they cut to get the price down while keeping the same quality overall.
It's also not entirely uncommon for an App Store synth to offer both an iOS and a native Mac version so always check the store description to see if its universal. The ability to seamlessly bring your tracks over to a more full-fledged DAW on your Mac is really nice.
Example: Minimoog Model D Synthesizer
https://apps.apple.com/us/app/minimoog-model-d-synthesizer/i...
Do iDevices not support hardware (USB) MIDI?
Now that I understand most of it, I am really considering buying a ARP 2600 replica.
So yes, the switch from software to hardware comes with time. But, at least for me, the first step is cheap apps on my already-owned tablet.
Small comments/interrogations regarding hardware vs software in this post:
https://news.ycombinator.com/item?id=45235398
May be you have some opinion regarding these.
And something like VCVRack is heaven to learn, experiment and understand what one can do with synthesis, step by step.
Experiences vary but sliding a slider on a screen is worth the benefits.
I mean, it's terrific to have an affordable replica, especially for discovery, I'm not debating the price-point advantage (for both acquisition and maintenance), but this is not an on-par replacement.
In an analog (less so in digital, but still somehow) synth, the controls are the instrument itself: they are in a specific place, react in a specific way, and physically part of the device that outputs the sound, and they stay there: you cannot move one without the other. The instrument has its own character. It's still more abstract than a classical instrument like the violin or the piano where the physical action alone is done and felt in real time, of course. It's significantly more incarnated than software + generic (in a good way) controllers.
The good side of this is that after having software replicas or original synthetisers, there's room to build new exciting embodiments/physical instruments.
Conversely, the likelihood of making it big just by making some good damn music was never lower than it is now. Makes for a fine hobby though.
Is that statement backed by any facts? Otherwise it sounds like a soundbite that sounds good, but I'm not sure how true it is. Maybe what "making it big" has changed more compared to how many people make their living making music, which for me would be enough to be considered "making it big".
[but when you simply ignore the marketing , and are a bit picky in your choices, the current offer is 10000% more qualitative than it has ever been. And BIG THINGS happen behind the curtain of mass marketing]
I believe so: in an aging softsynth community I still mingle with occasionally, everybody who is still actively involved with music seems to have either moved on to genAI, or to soft-on-Rpi for better integration with real instruments (including synths of all kinds).
The beauty of a hobby is that you do it for yourself, not for others.
So even in a (terrible) world where 100% of commercial music was AI-composed, someone's hobby of writing music by hand would likely remain unaffected.
Disappeared from where? In terms of units moved I'm guessing there's an order of magnitude more sold today than in the 90's or 80's.
Pretty well, I believe. The joy of playing is largely the act itself, becoming one with your instrument and stepping into a world outside of time. Composition is an adjacent pastime.
https://www.arturia.com/products/hardware-synths/astrolab/as...
This is without even referencing the huge cross-pollination and massive influx of development in the Modular Synthesis scene spurred on by things like vcv rack and its EuroRack ports.
In short, it has never been a better time in history to be a hardware synth enthusiast, and it's mainly down to soft-synths popularising the unique sonic qualities of historic hardware synths.
I mention this to make a point: you can't transform synths just by running some generic DSP code on a Pi and putting it in a box. Sound processing is also being transformed, and whether it's something like Hydrasynth generating poly aftertouch (but aliasing and not sounding that different from a VST) or Novation Peak/Summit receiving poly aftertouch (not generating :D ) but generating sound using custom hardware, sitting a VST on a Pi isn't going to get you a transformative synth.
Thing is, if you're able to dig into stuff like my DSP codebase that is actively under development AND plunk a VST synth onto a Pi AND do something interesting with the physical controls to direct the synth engine, that's starting to look transformative again. But just knowing about Pi isn't enough, you'll have to have a deep background in soundmaking and the ability to instrument-make in an interesting way.
If you have those things… game on. You can begin work FAR more cheaply than ever before, and that is how the Pi could be transforming synths.
I'm waiting for 24/96 audio hats to be common before I dig into this, even for stompboxes. I'm given to understand Electrosmith Daisy already has this, and that's a similar class of 'system on tiny board' that should be considered an audio Pi-like.
And you're absolutely right about the documentation.
You can use the Pi 2/3/3a/Zero 2 to build things like an mt32 or DX7 emulator almost trivially, and they make for great DAWless modules.
https://github.com/seclorum/simdsynth
Its an 8-voice polyphonic synth with 1 oscillator per voice, a filter, an LFO, and EG's for the Osc and Filter.
I've been extremely happy with the performance I'm getting, running on the Raspberry Pi - in both Monome and Zynthian systems!
Monome and Zynthian are both game-changers for FOSS audio hackers. I have both running side by side and they are just a pure inspiration for audio exploration. It's very rewarding also, to be able to put my own code alongside all the other great stuff from both communities.