Rap and rap music has been around the for nearly 40 years now, all of it started with travelling musicians who spoke poems to a playing melody. Also it did sound quite like the hip hop music made today. Should you hear a rap beat minus the vocals, which is called an instrumental, frequency higher certain patterns playing over and over again. These are called loops. So, a rap beat includes different loops, which each is slightly different from the other person. In a loop you will find the drums, the baseline, the melody and the effects. - Ice Cube type Instrumental
Let's start with all the drums. Here we have the kick, the snare or clap and the hi-hat. Compare a house beat having a hip hop beat, and you will probably hear the difference. In dance music, like house and techno, a kick or snare hits on every beat, therefore the time distance involving the drum sounds is always exactly the same. In hip hop, the sounds are slightly off of the beat, which makes the beat sound laid back and slower. The hi-hat completes the sound array of the drums. We now have the kick on the low frequency, the snare on the middle and the hi-hat on the high one.
The base line shouldn't be too complicated in rap, it just fills the low frequency, but it should sound good though. For me, the sound-quality is more important than the melody itself, but people have his own style. Make absolutely certain it hits on some of the same notes since the main melody.
Ok, now let's discuss the melody. Here, the sounding and the melody itself are essential. Many producers focus on the melody prior to the drums. And there's a valid reason: the melody will be the part people remember most when they heard the song. Make sure you have a middle frequency melodic sound along with a high frequency one. Like with the drums, the beds base and melody should fill in the whole frequency range. In that case your beat will sound complete.
Last but not least, the effects. Many people underestimate the effectiveness of good effects. Producers use their particular special sound effects to perfect their beats, and if you hear those, you know exactly who it was. Timbaland, for instance uses his background singing and Lil'John shouts "yeah!". It's not exactly a sound effect but meets exactly the same purpose.
I hope you are in possession of a good overview of the dwelling of hip hop beats. It's much easier to explain this on an example when you can hear it. I recommend you viewing tutorials online and listening to some good hip hop instrumentals to fully understand this. And don't forget: simplicity is key. Don't overdo it to make your beats too complicated. - Ice Cube type Instrumental