Thread: Tell me about Synths!!

Hi! Welcome to the wide world of synths. I am merely a dabbler but can answer some starters.

You are correct in thinking that a synthesizer is not like a MIDI controller. It's more like a digital piano keyboard where you can change the sound. Some do have MIDI input though.

To start, let's go to what a synthesizer does. It gets its name from the fact that it's synthesizing the sound electronically from the ground up. This starts with a sound wave (originally generated by circuitry in what are now known as analogue synthesizers, but more often generated by computers these days. Some people say analogue synths sound better in general). There are four basic flavours of analogue sound waves - sine, square, triangle, and sawtooth. These all have particular characters as well. Go and search each of them up on the web - I'd get links but I'm a little time poor currently.

After this sound is generated, the qualities of it are altered by various things.

Starting with filters - they are a synthesist's best friend. Hi-pass and low-pass like you referred to are types of filters. Additionally there's band-pass, band-cut, hi-shelf and low-shelf; but the first three are the only really important ones currently. What filters do is they filter off certain frequencies from the sound that you designate. I presume you know something about frequencies of sound (the human ear hearing up to 20,000hz, etc). An example would be if you set a low-pass filter at 2Khz. This would remove from the initial sound wave any part of the sound that went over 2khz, leaving you just with the bits that were 2khz and below - letting the low frequencies pass, hence the name. A high-pass would mirror this, only letting frequencies above 2khz past.

Filters generally do not cut off directly at the frequency you tell them to, however. They use a frequency-volume curve where frequencies above the one you set become quieter and quieter until they're inaudible. This can be an extremely shallow curve (still allowing plenty of volume at 3khz) or an extremely steep one (no more sound at 2.05khz). Band-pass filters work in this way - you set a frequency, and frequency-volume curves go off in both directions, only allowing midrange frequencies to get through.

Envelopes shape the sound, generally by tinkering with the volume; but envelopes can be applied to any element. You will probably come across the term ADSR. This stands for Attack-Decay-Sustain-Release, and is what envelope generators normally use. Let's imagine a theoretical envelope generator, set to:

Attack - 30 milliseconds
Decay - 2 seconds
Sustain - -6db
Release - 1 second

What this means:

Attack is how long the sound takes to go from zero to full volume. In this example, your synthesizer's sound will sweep up in volume from zero to full in 30 milliseconds after it recieves the signal to start.
Decay is how long the sound then takes to get from the highest point of Attack down to the set Sustain level. In this case, after the 30 millisecond sweep up, it will decline in volume for 2 seconds afterward until it reaches -6db.
After that, the sound will continue until you let go of the key. Release then designates how long it takes after the key is released for the sound to fade out into nothing - one second, in this case.

Envelopes can be applied to many things but I'll let you fiddle with that when the time comes. Volume and filters are the two most commonly done.

I'll explain more about oscillators, effects and basic synth patching, but right now I'm out of time. PM, if you wish.

Wow! Thanks a ton! You made that all really easy to understand. Now I'll be able to get a bit more fun out of my iPhone synths... 'cause I now actually know what some of the knobs do!! Haha.

I'd love to hear about oscillators and anything else that you think is important for a beginner whenever you have the time to. I won't be able to pick up a synth until well into may or june anyways.

Thanks a bunch!

Oscillators oscillate..

I'll try to lie to you as little as possible (you know, glossing over the sticky icky).

Synthesizers run on modules

modules have two categories: generators and processors
Generators CREATE a signal (a signal can be though of as a stream of numbers, or a stream of audio(NOT ALWAYS AUDIO)).
Processors take a signal in, DO SOMETHING to the signal, and send it along it's merry way.

Generator examples: oscillator, lfo, envelope(yes envelopes are generators).
Processor examples: filter, compressor, delay (think fx).

So, you normally start with some form of generator, pass it through some processors, and send it's final signal to the output (whatever that may be, but usually some speakers).

An oscillator is a generator.

ok, an oscillator just moves in a shape (sine wave, triangle wave, square wave, complex waves, noise, etc) between two numbers (usually -1 to 1 when producing audio) over and over again at a designated frequency. Generally an oscillator in a synthesizer is used to generate the audio. Hence the oscillator falls into the generators category. When the frequency is high enough (between 20Hz and 20kHz roughly) it will create hearable audio. Usually your MIDI input (if you're using one) will control the frequency of the oscillator(s) to control their perceived pitch.

an LFO is a generator. It stands for Low Frequency Oscillator.

in a perfect world an LFO is EXACTLY the same as an oscillator. In the real world though, an LFO usually is constrained to low frequencies (0 to 25Hz ish) and using a very high resolution wave form (since it's slower, it needs more numbers packed closer together in the digital/discrete world).

Let me go back over filters very quickly again. Lsea did a pretty good job explaining, but I'll give a bit more insight. How about the low pass filter in general. Low pass means "let low frequencies pass," so we can expect a low pass filter to greatly diminish the high frequencies (a filter can never truly remove frequencies completely). What this will mean is if you're looking at a wave form, the more high frequencies you cut, the "smoother" the wave form transitions will appear to be (a square wave will start to turn into a sine wave). So you can think of control signals. Say you recorded yourself twisting some knobs, but you think the knob transitions are too quick, or too jagged, not smooth enough. You could slap a low pass filter between the recorded control signal before it hits the actual parameter that it's trying to control. Barf, I just reread this filter shenanigans and it's strangely difficult to explain this without getting way too deep, so just remember that you can use a filter for more than just audio tone (a common practice is to low pass your midi keyboard input before it hits the oscillators which will give you the glide effect between notes (portamento)).

Also, hmm, envelopes. The important thing here to keep in mind is that an envelope is a generator just like an oscillator. It generates numbers between 0 and 1 over time (Lsea did a good job explaining the times). These numbers are then multiplied against another signal. *USUALLY* the env signal is multiplied with the audio signal (osc or otherwise) to create a sound that has a natural rise and fall. Think logically now, what happens when you multiply a number by 0. Now what happens when you multiply it by 1. Now what happens if you multiply somewhere in between there. Envelopes multiplied by a signal will give you that same signal scaled over time as if someone were turning the signal up and down. Envelope, nice name for it, don't you think?

anyway, hope some of this helps. I may also chime in again later with some more fun.

In the mean time, if you're super interested in learning what's going on from a fundamental level, do some searching around for the term "modular synthesis." This is basically the craft of piecing together various synth modules to make a specific sound (this is usually constrained quite a bit in most synthesizers, since truly modular synthesizers can be very very daunting to the beginner, but learning modular synthesis will help you better understand the parameters given in your synth of choice).

The Nord G2 Modular demo is free to download and will let you mess around in a modular environment. The interface is ugly as hell and the demo is limited to mono, but it gets the job done if you're just looking to learn.

Well I remembered I'd forgotten this and came back to explain but I think Artelis has done a good job in putting the other stuff up there.

you dont even need to buy a synth, so long as you have a computer, there are plenty of freeware synths available. For example, try searching for 'lmms'
it includes an array of synths that should keep you busy for a whille, and best of all, its free! I tend to use it alot for makeing electronic/dubstep type music. Hope my advice helped.

Originally Posted by coolking95

you dont even need to buy a synth, so long as you have a computer, there are plenty of freeware synths available. For example, try searching for 'lmms'
it includes an array of synths that should keep you busy for a whille, and best of all, its free! I tend to use it alot for makeing electronic/dubstep type music. Hope my advice helped.

no no, silly, this thread is about learning synth theory. How to manipulate a synth to your heart's content. But this is also true. Tons and tons of free softsynths out there, even some modular ones for learning the low level theory. I recommend the Nord G2 Modular "demo" from their web site for learning modular synthesis. It's "monophonic" (not really, but kinda, heh), and doesn't include all the modules, but pretty much everything you need to learn the basics is there. It's what I learned on, anyway. There are probably better. I'd recommend learning modular synthesis on Reaktor if you want to pay for something, and Max/MSP if you want to learn it from an electrical engineering point of view.

Haha don't even bother with the micron, save up another 150 and get a microkorg xl, I have one and it's great for me because I mostly try to make crazy whack sounds with it.

I have a friend with a micron. let me puut it this way, he's borrowing my microkorg.

Of course, being on the weirder more experimental side of synths, I am saving up for a circit bent keyboard, those things are the shit!!!

Just don't buy anything by Casio and you're gold. I was looking at getting a synth for my girlfriend's birthday under $300, and I got a few recommendations from Ultimate Guitar that I'll block quote here:

Originally Posted by Business

Owning a bunch of synths, I'ld recommend the Yamaha DX7, a synth from the 80's that has been used by everybody, and still is today.

Originally Posted by lan_the_fox

or a Roland SH-201.

This Casio actually looked good for the price. Do what you will:

Originally Posted by Mishakuz

I bought a Casio WK-200. They sell for around $200 here. It comes with lessons, simulates effect of weighed keys, has decent sound, has a large LED display onboard that shows you the note you're playing. It can also connect to a computer via USB.

Originally Posted by Business

Other interesting models in the price range:
Akai AX73 (Analog)
Korg M1 (Rompler)
Korg DW-6000 & DW-8000 (Digital Waveform)
Roland Alpha Juno 1 & 2 (Analog)
Roland D50 (Linear Synthesis / Rompler)
Roland JX3P & JX8P (Analog)

again, this thread is not about BUYING synths. It's about learning synthesis theory.

but while we're on the subject, I'll chime in here about the microKORG. I bought one for $500 new, a year later I sold it as quickly as possible for $150. It's a piece of shit. The programmability is limited, and it sounds like ass. I'll agree with the DX-7. It sounds pretty sweet, but it really only does FM (frequency modulation), so if you're thinking about purchasing one, I would look up FM theory, and examples of various FM sounds (they tend (emphasis on 'tend') to make more stringy (think violins), evolving timbres. It can do plenty of other sounds as well (and theoretically, any synthesis technique can make any sound imaginable), but with a basic understanding of FM, this is usually what you'll come up with. But on the whole, it sounds awesome, and you'll be making Daft Punk Tron Soundtrack synth sounds in no time!

Originally Posted by Artelis

again, this thread is not about BUYING synths. It's about learning synthesis theory.

The OP hinted that he was looking to buy one. I don't see why we can't give him a few recommendations.

Originally Posted by Artelis

again, this thread is not about BUYING synths. It's about learning synthesis theory.

but while we're on the subject, I'll chime in here about the microKORG. I bought one for $500 new, a year later I sold it as quickly as possible for $150. It's a piece of shit. The programmability is limited, and it sounds like ass. I'll agree with the DX-7. It sounds pretty sweet, but it really only does FM (frequency modulation), so if you're thinking about purchasing one, I would look up FM theory, and examples of various FM sounds (they tend (emphasis on 'tend') to make more stringy (think violins), evolving timbres. It can do plenty of other sounds as well (and theoretically, any synthesis technique can make any sound imaginable), but with a basic understanding of FM, this is usually what you'll come up with. But on the whole, it sounds awesome, and you'll be making Daft Punk Tron Soundtrack synth sounds in no time!

The Microkorg isn't that bad, It does sound cheesy sometimes but I got a sweet deal on mine. Craigslist and other deal sites are kind of rare to get here in hawaii because they either can't ship or have incredible shipping rates. I have never seen a synthesizer on A kauai Craigslist ad in my entire 2 years of using craigslist, so I was really lucky to get a 400 $ microkorg (with shipping too) from ebay.

That was like when it was new though, now you can get them for that price easily.

Originally Posted by celestialelixir

The OP hinted that he was looking to buy one. I don't see why we can't give him a few recommendations.

yeah, don't know why I got all snappy. Sorry about that.

Ok, well the channel vocoder on the microKORG can be pretty fun to fool around with. The interface is just sooooo obnoxious to use for modularity. Sometimes I have a hard time interpreting the three letter representations of words. Not exactly a good way for a beginner to learn synthesis if they can't even tell what the hell the words on the screen are

I figured as much, that's why I've heard something like the Roland SH-201 is good for beginners... 'cause every 'variable' has a nob or slider so it's easier to visual and use.