By Hannah Beckett, RPT
Pitch Correction: A method of tuning that compensates for excessive pitch variances.
If you have been a technician for any length of time, you’ve probably already discovered that pitch correction is a very subjective term, and opinions on when and how a pitch correction should be performed vary from technician to technician. This is likely due to the broadness of the term, and the varying circumstances in which it applies. A piano that is at 436 Hertz (Hz) would qualify for a pitch correction. A piano that is at 428 Hz also qualifies for a pitch correction, but you might want to consider different methods for different extremes.
This article will teach several different techniques and when it might be appropriate to use them. This article also assumes that the pitch correction is being performed on an in-home piano that was manufactured post-1980. Margins on what might be considered a pitch correction in an institutional or concert setting are far narrower than on an in-home piano.
Pitch corrections on spinets or other poor-quality old pianos are not advised as these pianos are at risk of structural or string failure.
Before the Tuning Lever Comes Out
While we technicians love our expensive tools, we must remember that attention to detail is the most powerful tool we carry. We must keep this tool sharp by exercising it frequently, particularly in regards to pitch correction. A thorough examination of the piano is critical before beginning a pitch correction. Before your tuning lever comes out, you must first determine if there are any conditions that would make the pitch correction impossible.
Examine the structural integrity of the piano. Are there any cracked bridges? Separated ribs? Is the pinblock capable of holding the tuning pins at pitch?
Carefully examine the strings, coils, and bearing points on the piano. Is there a lot of buildup on the strings that could prevent you from pulling the piano to pitch? Will the buildup likely cause string failure in the course of the tuning? Perhaps you should consider running a line of CLP over the bearing points to minimize the risk of string failure. If a bass string breaks, does the cost of the replacement outweigh the piano’s overall value?
Beyond examining the structure of the piano, communication with your client is critical before beginning a pitch correction. A pitch correction is always a process that requires multiple tunings. Is your client informed about the cost and willing to go through with the repairs that may ensue? In a worst-case scenario situation, your client will not remember you as the technician who tried to fix their piano, but as the technician who broke their piano. Weigh the cost/benefits before you undergo a pitch correction on a questionable piano.
Once you’ve decided to proceed with the pitch correction, you have many methods to sort through to choose what may be most effective for the situation at hand. Whatever method you choose, it is important to leave the piano sounding “in tune” regardless of where the pitch ends up. Much of the time, you will be working with a new client when you encounter a pitch correction situation. Leaving a new client’s piano sounding poorly after you’ve tuned for two hours leaves a bad first impression.
Method One: The Overpull
Most electronic tuning devices (ETDs) have a pitch correction setting that automatically calculates overpull to compensate for the drop in pitch that will happen over the course of the tuning. This method is safest on pianos that are unlikely to break strings or even worse, a plate. If the piano responds well, you may only have to go through one pass before the piano is stable and singing again.
Suggested pitch range for this method: 436-438 Hz (-16 to -8 cents).
Method Two: Fast-Pass Pullups
On a high-quality piano that hasn’t been properly maintained, it is possible to pull the piano approximately two-thirds of the way up, then follow up with a second pass that pulls it the last third of the way up. I recommend tuning all center strings very quickly and approximately, then do the same for unisons. Don’t worry about getting clean unisons; you are just trying to get all three strings somewhere similar in pitch before you tune for the second time. When you start the tuning, the piano should be at a pitch that is more consistent with a piano tuned once or twice a year. The second pass can be your fine-tuning. Err on the side of sharp when going up to the treble, but not such that it is noticeably over-stretched. A high-quality piano will typically stabilize by the second pass.
Suggested pitch range for this method: 435-438 Hz (-20 to -8 cents)
Note: Conversely, a two-pass method is my only recommendation for pitch lowering. Pianos that are between 443-446 Hz (+12 to +24 cents) can usually be lowered without moving pitch below 440 Hz. Pianos that are slightly sharp are far more acceptable than pianos that are flat. There is no need to move pitch below 440 Hz to achieve a well-tuned piano.
Method Three: Slow and Steady
This method works well on more extreme pitch corrections, or if you have concerns about the piano’s ability to sustain a large tension change. An incremental change (3-4 Hz at a time) in pitch is a much more gentle way to coax the piano back up to pitch without causing major problems. This method is basically a series of Fast-Pass Pullups spaced out over time until the piano is stable. This typically means a second tuning approximately one month after the first, perhaps another in three months, another in six, etc., depending on how far flat the piano is at the start date. Before doing this approach, carefully explain this method to your client and why you recommend it for their piano. It is important that they understand the process and can commit to seeing it through to the end. Booking the follow-up appointments before leaving is a good idea. Update your client on the progress as you go, and agree on a healthy tuning schedule to stick to once the piano is stable and at pitch again.
Suggested pitch range for this method: 428-434 Hz (-48 to -24 cents)
Method Four: Playing Favorites
Sometimes one section of the piano will be far flatter than the other two sections. If the other two are close to pitch, start with the section that is the flattest (typically the treble) and plan to go through it twice. Tune it once on the first pass, then go back for a second pass once you finish the other two sections. You may find that it has drifted slightly from where you left it. Going through the weaker section twice will give you a better overall result that is more consistent with the other sections of the piano. For example: When a client complains the bass is very far out of tune, measure octaves between the bass and tenor notes. If the plain wire notes have sagged much flatter than the bass, begin your pitch raise on the plain wire and move through the bass on the second pass.
Method Five: Aural Fun
For those who are confident aural tuners, or for those working on developing aural skills, it may actually be a bit faster to pull A4 up as far as you feel comfortable and do a very fast aural tuning focusing on settling octaves slightly sharp. Your second pass could be fine aural tuning the piano with the pitch it settles at during the first pass, or using your ETD for the second fine-tuning. This method is good for beginner aural tuners who need to increase their speed and refine octave recognition abilities.