Scratching super fast is a skill that the vast majority of scratch dj's strive to acquire. Unfortunately, the typical approach you likely have taken for building extreme speed is severely ineffective. There are several things that must be considered if you want to build speed effectively. Missing any of it will prevent you from scratching at the most extreme speeds possible.
The Average Strategy is Tempo Boosting
While boosting the tempo has its benefits, it's not the sole way to build speed. Most people assume if they keep increasing the tempo and trying to scratch over it that they'll eventually be able to scratch faster. However, as already mentioned, a lot more must be considered and consciously worked on if you are to achieve any major results.
Think about it like driving at extreme speeds. If you are driving on a race track built for insane speed it doesn't guarantee that you will be able to drive extremely fast. You still need the right kind of vehicle and highly developed skills to fly through the race track at a lightning pace.
Efficiency of Movement is Crucial
If your record hand and fader hand are moving inefficiently then you will never scratch as fast as possible. Being efficient means achieving maximum results with minimum effort. Typical examples of inefficient movement are moving the record forward and back too far from the starting point, opening the fader too far from the cutoff and releasing your fingers too far away from the fader.
Clearly, the more movement you use in your scratching where it isn't needed, the longer it will take to do those things, thus the slower your cuts will be. What you want to do is identify where you're being inefficient, how inefficient you are in each area and how to become more efficient when you scratch.
Relaxation is at the Heart of Speed
One thing you may have noticed when scratching at faster tempos is it can be challenging to relax. What you must realize is that the more relaxed you are the more easily you can scratch efficiently. This is because when you tense up, you tend to overdo your motions even if you're consciously making an effort to move efficiently.
That's why it's very useful to scratch over more mellow tempos, such as 80 bpm and below, so you can focus on learning to scratch in a very relaxed manner while still attaining higher levels of speed. When you successfully do this it enables you to handle much higher tempos in a more relaxed mental and physical state.
While mellow bpm beats will help naturally put you in a state of relaxation, you still have to learn more aspects of the physical side. Learning to optimize your record hand pressure, fader hand tension and overall physical relaxation when scratching will greatly increase the fluidity of your movement which all leads to greater overall speed.
Good Timing Equals Further Relaxation
In addition, you need to time your fader movements well with what your record hand is doing. This will allow you the chance to rest between record movements, so that you are not building up unnecessary tension in your fader hand. The better you are at doing this, the more consistent your relaxation will be and the more you will scratch clean and fast, because you are learning to click the fader at the right moments.
Measuring Your Speed Leads to More Speed
It's essential that you also have some set parameters so that you're aware of how fast you're actually scratching. How many notes you execute per beat will determine how fast you are at the current tempo you're scratching over. 1 note per beat is quarter notes, 2 notes per beat is 8th notes, 3 notes per beat is 8th note triplets, 4 notes per beat is 16th notes, 6 notes per beat is 16th note triplets and so on. This is assuming you know basic counting over a 4/4 beat which is the typical time signature for most scratch beats.
It will be partially helpful to know how many notes there are for each scratch technique and combo you are working on, but you also have to keep in mind repetitions per beat. For example, if you are performing one technique per beat, then how many notes that technique is made up of will represent your speed. However, in order to increase your speed without increasing the tempo you have to add repetitions of that technique.
The more repetitions of a technique you can do per beat will represent your true speed of that technique at the chosen tempo. It is only when you have maximized your reps of a technique or combo per beat that boosting the tempo will be necessary to further gain speed. Remember though, it is all the areas of your scratching that I've discussed that will need to improve for you to actually gain speed. Boosting the tempo once you have maximized your speed at a lower tempo only puts you in a position to continue accurately measuring your speed.
Don't Underestimate Building Speed
While I have covered a lot about dramatically increasing your speed, there is much more detail that will need to be understood and applied to truly reach your full potential. Often times it isn't just the depth of each topic associated with speed building, but also your own personal weaknesses and strengths. These personal aspects of your scratching are best addressed by a high quality scratch instructor who knows from their own experience how to scratch at extremely fast speeds and has successfully taught others to do so as well. Bottom line, the fastest way to learn to scratch extremely fast is to seek help from a mentor who can and will help you reach your goals.