Adjusting the let-off in a piano action is a crucial step in regulation, as it ensures that the hammer disengages from the string just before the note sounds, allowing for precise control over the piano’s touch and responsiveness. The let-off distance can influence the touch, tone, and overall playability of the piano. Here’s a step-by-step guide on how to adjust the let-off in a piano action:
Tools Needed:
- Regulation screwdriver
- Let-off distance gauge (optional, but helpful)
Steps:
- Prepare the Piano: Before adjusting the let-off, ensure the piano is on a level surface and properly tuned. It’s essential to have good lighting and a clean workspace to perform the adjustments accurately.
- Remove the Action: To access the action and the regulation screws, you’ll need to remove the piano action from the piano. If you’re not familiar with this process, consider seeking the help of a professional piano technician.
- Locate the Let-Off Regulating Screw: The let-off regulating screw is usually found near the back of the key, closer to the hammer butt. It may be accessible through a small hole in the action rail or a slot on the key.
- Set the Let-Off Distance: The ideal let-off distance is typically between 1.5mm to 2.5mm, depending on the piano model and personal preference. You can use a let-off distance gauge or a thin piece of cardboard to measure the distance between the back of the hammer and the string when the key is depressed. Adjust the regulating screw accordingly to achieve the desired let-off distance.
- Test and Adjust: After making the initial adjustment, replace the action in the piano and test the keys. Play each key slowly and observe the let-off point. If the let-off is too close to the string, the hammer may not fully engage with the string, resulting in a loss of volume and tone. If it’s too far, the hammer may remain engaged with the string too long, leading to unwanted sustain. Make small adjustments to the regulating screw as needed to achieve the optimal let-off distance.
- Check for Consistency: Regulate the let-off for all keys, ensuring consistency across the entire keyboard. Each key should have the same let-off distance to maintain uniform touch and responsiveness.
- Voicing (if required): During the regulation process, voicing the hammers might be necessary to ensure an even and balanced tone. Voicing involves shaping the hammer felts to achieve the desired sound.
- Tuning: Finally, tune the piano to ensure that the strings are at the correct pitch.
It’s essential to approach let-off adjustments with precision and caution, as improper regulation can affect the piano’s playability and tone. If you’re unsure about the process or lack experience in piano regulation, it’s best to seek the services of a qualified piano technician. A professional technician has the expertise and knowledge to adjust the let-off and perform other necessary actions regulation, ensuring your piano performs optimally and delivers a satisfying playing experience.