A bassline is used in many kinds of electronic music.
It can be as simple as a single soundfile of a square or sawtooth or sine wave- if the bassline will not change much in pitch this is a good technique for a tight, clean sound.

example 1: make a sawtooth wave in Sound Forge- use the same frequency as your kick drum or at least be aware of their pitch in relation to each other...Make a sound and then load it into an audio track in your sequencer... use the envelopes (fade in and out) in your sequencer to control the time response. I usually use some eq like a high shelf above 180hz to reduce the high frequency components of the sound and make it seem more bassy.

Create new file.



Select Tools -> Synthesis -> Simple



It can be a synthesizer, hardware or software, that is making the bassline sound- this is good when you want to play different notes with the bassline...
This is the usual way producers make basslines. A person uses a low pass filter and uses the amplitude and filter envelopes of the synth to control the frequency response over time.

example 2: use Steinberg CS-40 to program a bassline...

Here is an example of a straight monotonic psytrance bassline...



Here is an example of a groovy "full-on" trance bassline:



Here is an example of a "progressive" bassline:



You will note that in these examples the bassline is NOT at the same time as the kick. this keeps the bass frequencies of each from bothering each other. This results in cleaner sound. For many styles of music this is not possible. Think of house music for example. You might have a bassline like this:



You will notice that the bassline sometimes hits at the same time as the kick and the two interfere with each other and create uneven levels... The solution? a compressor on the bassline that is "sidechained" from the kick channel. This means that when the kick is kicking it will lower the volume of the bassline until the kick goes away... this allows you to control the bassline. for this you will need a compressor that is capable of accepting another audio input as the "sidechain" trigger. I am using a sequencer called Orion by Synapse Audio for this example as a sidechainable compressor is a built-in plugin in this application.



Anyway- the sky is the limit with Bassline- but remember- what bassline you use determines the general genre or category of music in most peoples minds...

Have fun and good luck!