A fader scratch test checks the speed, smoothness and silence of a fader when you cut a sound. It requires neither a rare dubplate nor a big sound system. All you need is a clean rhythm track, a pair of headphones and a few minutes.
Scratching quickly reveals what your ears might miss during a long mix. A fader that cuts too late weakens every chirp. A crossfader that crackles turns a simple phrase into a struggle. At home, this test helps you set up your kit for playing, not to compensate for its behaviour.
Why carry out a scratch fader test at home?
Scratching relies on the precise moment the sound kicks in. This point is often called the ‘cut-in’. If there’s too much travel left before the sound kicks in, your hand is working for nothing. You have to move the fader further, so your cuts lose speed.
Conversely, a very short trigger requires a more precise hand. This is great for quick transitions or sharp cuts. But a DJ who mainly plays roots records might prefer a slightly longer travel. The right setting depends on your technique, not on a universal value.
The test also helps distinguish between a setting issue and a mechanical problem. An irregular cut on just one side isn’t down to a poorly chosen curve. Hiss that remains even when the fader is closed may be due to the gain or the source. Always start by observing before adjusting the settings.
The equipment needed to test the fader
Choose a track with a clear attack. A drum break, an isolated snare drum or a percussive loop works well. Avoid pad sounds or busy intros. They mask the actual moment of the cut.
Set your listening volume to a steady level. You need to be able to hear minor flaws without straining your ears. Place a source on each side if you want to test the crossfader. For a channel fader, a single source is sufficient.
Rane’s technical guides on crossfader settings highlight a useful point: the curve alters the relationship between the physical travel of the fader and the sound level. This explains why a fader may seem slow, even when it is working perfectly.
Crossfader test chart
| What you’re playing | What you’re listening to | What this indicates |
|---|---|---|
| Slow opening from the centre towards one side | The sound comes in gradually or all at once | The curve is gentle or steep |
| Small back-and-forth movements near the edge | The sound appears from the very first movement | The cut-in is short or long |
| Rapid cuts on a crisp beat | Each attack remains crisp and consistent | The fader follows your movement |
| Fader closed, source playing | Silence, slight leakage or noise | Possible level adjustment or wear and tear |
| Same movement on both sides | Identical response on the left and right | Balanced travel or localised fault |
How to carry out the test without beating about the bush
Play your loop, then close the crossfader completely. Open it very slowly from the edge. Listen for the first moment when the beat comes through. Repeat this movement five times at the same point. If the sound comes through at different positions, don’t jump to conclusions. First, check that your source level remains constant.
Next, move on to short cuts. Do simple taps, then regular transitions. Don’t worry about performance. Your aim is to hear whether the fader cuts cleanly on every pass. A cut that disappears once in ten goes is worth checking.
Test both ends of the crossfader. Some DJs only use one side, then discover a discrepancy the day they switch directions. This comparison takes less than a minute. It prevents you from having to adjust your technique to compensate for a subtle fault.
Finally, experiment with the curve. Start with a fairly tight curve if you’re looking for crisp cuts. Gradually open it up until you feel a more expressive response. Play the same phrase again after each adjustment. Changing just one variable at a time gives a clear result.
Linear fader or scratch crossfader: what are you testing?
The linear fader is the vertical slider for each channel. You move it up to bring a track in, and down to fade it out. It controls the volume of the relevant channel without affecting the other source.
The crossfader is the horizontal slider positioned between two channels. On the left, you hear channel A. On the right, you hear channel B. In the centre, both can be heard simultaneously, depending on the selected curve.
A channel fader allows you to control a long, gradual fade-in. This is the natural way to let a bass line breathe, introduce an instrumental version or bring a vocal back in. The movement remains precise, but the travel distance requires a greater range of movement.
A scratch crossfader is designed for an immediate response. With a steep curve, just a few millimetres are enough to open or close the sound. This is what enables sharp cuts, chirps and rhythmic accents on a vocal phrase.
Table: track faders and crossfaders in practice
| Control | What it controls | Natural gesture | Use in a dub set |
|---|---|---|---|
| Linear fader | The level of a single channel | Raise, hold, lower gradually | Fade in a riddim or fade out a vocal without breaking the flow |
| Scratch crossfader | The transition between track A and track B | Switching, cutting, and quickly restarting | Cut a vocal, drop a beat or alternate between two sources |
| Crossfader curve | The speed at which the sound fades in | Adjust to suit your touch | Go from a smooth fade to a sharp cut |
| Trigger threshold | The distance before full opening | Reduce or widen the dead zone | Achieve short cuts without straining your wrist |
The choice isn’t necessarily mutually exclusive. In a live session, the linear fader sets the scene and the crossfader sets the action in motion. You can adjust your track levels before the track starts, then use the crossfader for playing with the interplay between the two sources.
This method avoids a common pitfall: trying to do everything with the crossfader. If the track gains and faders are set incorrectly, your cuts might be clean, but the overall level will spike. Scratching starts with a well-prepared source.
Adjusting the curve and the trigger threshold
The curve controls the speed at which the volume rises during the run. A gentle curve is suitable for fades and transitions. A steep curve concentrates the level near the edge. This is the one many players look for when scratching.
The trigger threshold acts even closer to the end. It defines the distance your fader travels before allowing the signal through. A short threshold gives an immediate response. A longer threshold leaves a comfortable margin if your fingers still lack precision.
Here’s a practical and simple setting to try at home. Set a closed curve, then reduce the threshold until you can hear the beat from the very first few millimetres of travel. Do ten slow transitions. If you accidentally let the sound through between two movements, lengthen the threshold slightly. You’re looking for a stable balance, not the shortest possible trigger.
On the KLEMENTZ Dub Mixer, the scratch-optimised crossfader allows you to adjust the curve and the trigger threshold. This means you can switch from a sharp cut to a more gradual transition without adding an external unit. The mixer also retains its isolator filters, siren and delay in the same portable format.
This is useful when you need to keep your set-up simple. You’ll have fewer cables to plug in, you’ll find your settings more quickly, and you’ll spend more time playing. The Dub Mixer remains in stereo, which keeps your two sources in place during cuts and drops.
Issues the test may reveal
A crackling sound during movement isn’t the same issue as a slow fade-in. The former manifests as small audible glitches. The latter results in a fade-in that’s too gradual, but remains clean. Don’t adjust the curve to mask mechanical noise.
Sound leakage when the fader is closed also needs to be put into context. If a source level is set too high, you may hear residual sound that isn’t related to the fader. Lower the source gain, maintain a similar listening volume, then repeat the test. This step prevents false diagnoses.
If the behaviour remains erratic after these checks, note down precisely what you can hear. Is it always the same side? Is it linked to a particular fader position? Does it occur with another source? These details make communication easier if you need to contact the person looking after your machine.
KLEMENTZ crafts each Dub Mixer, hand-designed in France, with this type of use in mind. The brand produces small, carefully controlled batches and monitors its units over time. Over 360 users have left a review, with an average rating of 4.9 out of 5.
FAQ on testing scratch faders
What sound should you choose to test a scratch fader?
Choose a dry beat with a clear, repeated snare drum. A short loop allows you to compare each opening without changing your reference point. An isolated vocal track can also help, as consonants quickly reveal any soft cuts.
Do you need to test the crossfader with two sources?
No, a single source is enough to check the trigger and cut-off. Two sources come in handy if you want to control both sides in a situation that closely resembles your usual playing style.
Is a very steep curve suitable for all styles?
No. It favours quick cuts, but makes short fades less gradual. If you alternate between dub selection, transitions and scratching, look for a middle ground that you can easily return to.
Can you scratch with a linear fader?
Yes, but it will feel less natural. The vertical travel is longer and the channel fader is primarily designed to control volume levels. For frequent cuts, a crossfader set to a short travel responds better to the movement.
Why does my fader sound different through headphones?
Headphones make slight bleed and background noise more audible. That’s precisely why they’re useful during testing. Then check on your speakers to see if the issue remains noticeable in real-world use.
Repeat this test after every adjustment, then stick with the setting that really suits your style. A well-adjusted fader almost disappears into the mix: it lets you place the cut, trigger the siren or bring the delay back at just the right moment.
