csound-sampler alternatives and similar packages
Based on the "csound" category
Do you think we are missing an alternative of csound-sampler or a related project?
A csound-sampler is an easy to use sampler based on csound-expression library.
We can load and play audio files. We can play them back in loops, in reverse, at random segments with different pitch, apply any effects available in Csound. We can arrange them in sequences. We can easily create patterns of audio snippets.
How to install
The library is available on Hackage. So we can install it with cabal-install:
> cabal update > cabal install csound-sampler
Also we need to install the Csound compiler. It's software synth. It's going
to be our audio engine. When it's properly installed it should be possible to run the csound
at the command line. Open up your terminal and type in
csound. On windows sometimes csound
complains on missing
python27.dll. If it has happened with you download the dll from the web
and drop it in the folder
Let's review the main functions of the library.
How to load files and sounds
Let me introduce you to
Sam (Sam nods). He is the main guy in
the library. He can sing samples for you. All samples are in stereo.
We can listen to the audio file:
module Main where import Csound.Base import Csound.Sam audio = wav "samples/song.wav" bpm = 120 * 4 main = dac $ runSam bpm audio
Let's load the module in the ghci and invoke the main function.
ghci Main > main ... and the Sam sings ...
Ctrl+C to stop the program. Note that it's the best way to work
with csound libs. We can create module with common functions and imports then
we load it in the ghci and we can start messing around with samples right in the
We load the lossless audio files with function
If our audio file is mono we should use the function
wav creates a sample out of file name:
wav :: String -> Sam
To hear the sample we should run the
runSam :: D -> Sam -> SE (Sig, Sig) runSam bpm sample = ...
The first argument of the
runSam is the Beats Per Minute measure.
It's the tempo of the sample playback.
When the sample is converted to stereo signal we can hear the result
dac. It's a standard function form csound-expression library.
Ok, we can hear a sample. How can we loop it? There is a function
loop :: Sam -> Sam
To make things more easy let's create a couple of shortcuts:
module Main where import Csound.Base import Csound.Sam run = dac . runSam (120 * 4) song = wav "samples/song.wav" beat = wav "samples/beat.wav"
Let's save it as Main.hs. From nowon we are going to load the
Main.hs in the interpreter. So let's loop over beat:
ghci Main.hs > run $ loop beat
Let's add the voice on top of it:
> run $ loop beat + song
Sam behaves just like a simple number. We can add samples or
take a mean of samples:
> run $ mean [loop beat, song]
Changing the volume of the sample
But the beat is too loud we can not hear the voice properly. Let's fix that:
> run $ mean [mul 0.5 $ loop beat, song]
mul comes with library
It happens that the
Sam is the instance of
We can use the the function
mapSig to apply any signal transforms to it:
mapSig :: (SigSapce a) => (Sig -> Sig) -> a -> a
mul is just a multiplication by a signal.
mul :: (SigSpace a) => Sig -> a -> a mul k = mapSig (* k)
Playing parts of the sample
What if we don't want to hear the whole song but only
8 beats of it. We can use
> run $ mean [mul 0.5 $ loop beat, lim 8 song]
We can hear only a part of the song. But now we can hear a nasty clipping. The sound jumps at the and of the sample.
We can fix it with envelope:
> run $ mean [mul 0.5 $ loop beat, linEnv 1 1 $ lim 8 song]
linEnv takes rise and decay times in BPM and applies
a trapezoid envelope to the sample.
There are many more envelopes to explore:
-- | Exponential trapezoid expEnv :: D -> D -> Sam -> Sam expEnv rise dec = ... -- | Parabolic envelope hatEnv :: Sam -> Sam -- | Linear rise and decay envelopes riseEnv, decEnv :: Sam -> Sam -- | Exponential rise and decay envelopes eriseEnv, edecEnv :: Sam -> Sam
Playing samples in reverse
It's cool to reverse audio. The sound becomes mystic and SigurRos'y. We can play audio files in reverse:
> let revSong = wavr "samples/song.wav" run revSong
Notice the suffix
r in the function
Playing one sample after another
Let's play song in two modes. the first time forth and then backwards:
> let songLoop = let env = (linEnv 1 1 . lim 8) in loop $ flow [env song, env revSong] > let beatLoop = mul 0.5 $ loop beat > run $ mean [beatLoop, songLoop]
Notice the function
flow. It plays a list of samples in sequence.
If we want to put some silence between the song samples, we can use
rest. It creates a silent sample:
> flow [env song, rest 4, env revSong]
Delaying the samples
We want beat's to enter the song first and then after 4 beats delay comes the voice:
> run $ mean [beatLoop, del 4 songLoop]
We can use the function
Playing samples at random
What if we want to make our voice track more alive. We can introduce randomness in the choice of the sample:
pick :: Sig -> [Sam] -> Sam pick period sample =
pick plays one sample from the list with the given period:
> pick 8 [env song, rest 8, env revSong]
That's how we can play song back and forth with random playback modes. There is a function
pickBy :: Sig -> [(D, Sam)] -> Sam
pickBy plays samples with given frequencies of occurrence.
The sum of the frequencies should be equal to 1.
Playing patterns samples
We can play sample in the loop. But what's about more complex patterns?
we can create them with function
pat (short for pattern):
pat :: [D] -> Sam -> Sam
The first argument is the list of time length for sequence of loops. It's the drum-like pattern:
> pat [3, 3, 2] beat
It means play the sample
beat in the loop. The loop spans for 8 beats and
it contains three segments. The length of each segments is given in the list.
The pat plays the whole sample. When samples overlap it mixes them together.
If we want to play just a parts of the sample we can use the function
rep (short for repeat).
With it we can create complex drum patterns out of simple samples:
> rep [3, 3, 1, 2, 1] beat
Changing the tempo
We can speed up or slow down the sample playback with
str, wide :: D -> Sam -> Sam str speedUpRate = ... wide slowDownRate = ...
It doesn't changes the rate of playback. It changes the BPM measure. The looping or limiting functions will respond to the changes.
Changing the pitch and panning
We can change the pitch of the sample with function:
atPch :: D -> Sam -> Sam
It lowers (if negative) or heightens the pitch in semitones:
> let songLoop = atPch 2 $ loop song
We can change the pan with the function
atPan :: Sig -> Sam -> Sam
The first argument is the panning level. The zero is all left and the one is all right. We can easily create the spinning pan:
> let songLoop = atPan (uosc 0.1) $ loop song
Playing segments of the audio file
What if we like just one specific spot in the audio file and we want to loop only over it. we can read the segment with function:
seg :: D -> D -> String -> Sam seg startTime endTime fileName = sample
The times are measured in seconds. To play the segment in reverse
we can use the function
segr. There are mono variants:
Playing random segments of the audio file
We can create complex sound out of the simple one if we play segments of it at random:
rndSeg :: D -> D -> D -> String -> Sam rndSeg segLength startTime endTime fileName = sample
The first argument is the length of the segment. If we want to read segments from the entire audio file we can use the function:
rndWav :: D -> String -> Sam rndWav segLength fileName = sample
Sam is a synonym for generic type:
type Sig2 = (Sig, Sig) type Sam = Sampler Sig2
Sampler is applicative and function. We can easily apply
an effect with
> dac $ fmap magicCave2 $ loop song
We applied a reverb (
magicCave2 :: Sig2 -> Sig2). It's taken from the
If our effect produces side effects we can use one of the lifting functions:
liftSam :: Sample (SE a) -> Sample a bindSam :: (Sig2 -> SE Sig2) -> Sam -> Sam
If we want to now the current BPM we can use functions:
mapBpm :: (Bpm -> Sig2 -> Sig2) -> Sam -> Sam bindBpm :: (Bpm -> Sig2 -> SE Sig2) -> Sam -> Sam
And many more
There are many other functions. We can find them all in the docs. Happy sampling!