Valve Port Alignment & Calibration
When valve instruments are manufactured the pistons are machined as a mirror image of the valve casing so all of the port holes line up perfectly. From there typically, spring housings & other parts are soldered or screwed onto the pistons & felts of some variety are placed on top of the valve stem, on top of the valve cap &/or under the valve button. This final combination of felts, if done correctly, should allow the port holes in the pistons to match up perfectly with the according holes in the valve casing as the piston is depressed or raised.
Traditionally these felts have been, and with many manufacturers, continue to be made of a type of material that over time compresses & degrades as the instrument is used. As this occurs, the valves fall out of the factory specified alignment & need to be replaced. Also considering the material these felts are made of in many cases, they are not a particularly accurate or consistently made part of the trumpet so alignments can vary from horn to horn or even piston to piston in some instruments. Unfortunately another factor to consider is certain inconsistencies in overall build quality in some manufacturers who produce higher volumes of instruments, which would amplify the frequency and severity in such disparities.
Now the big question… does it matter? Yes, and for that matter every variable in a horn impacts how it plays for a given performer in some way. Everything from tube seams & metal gauge, to solder globs & tube edges… and alignments affect how the characteristics of an instrument behave. Will it help YOU achieve your desired results, is the question. As I've noted in the "Our Philosophy" section of this website, I don't approach instrument adjustments as a one size fits all or even guarantee certain changes will solve a specific problem in one shot. Over the years I've worked with countless players from every part of the music business. They all have different needs & goals that are unique to them and as such every tweak is unique, even if the same. I've been told to put dents back in horns because it changed the feel of certain articulations (which were clearly distinguishable). I've been told to loosen tolerances on slides or put foil tape on certain spots of the horn to dampen the feel. All of those things are mechanical imperfections & completely counterintuitive for me to do as a technician. Some may even seem like hocus-pocus that's in the players head… and sometimes it is, but it's my job is to make the horn play how the performer wants it to play for their given needs.
That said, valve alignments, while achieving optimal mechanical accuracy, are only yet another adjustment that can be performed on an instrument that can potentially help. If a player is finely acclimated to his or her instrument & an alignment is done not to correct a problem but only in the hopes it will make a good horn better, that is not always the result. For as many players who have benefited greatly by having their valves aligned, I can name just as many who after having it done, took out the new felts & put their old dingy ones back in because after the "honeymoon" period, they didn't like how the instrument played for them. All the edges and reflection points inside of a horn, good or bad, engineered or due to faulty workmanship, are all elements that regulate among other things, bore turbulence. Sometimes as counterintuitive as it may seem, leaving a certain imperfection alone might be just the right touch to make a horn feel like home.
If you do choose to have a valve alignment done I think it is also important to understand what is involved in the process & the options available so you can make the best choice for your instrument. I offer 2 different kinds of valve adjustments, per my Services page; "Valve Port Alignment" & "Valve Port Calibration".
Valve Port Alignments, or as most are familiar, a "PVA" is where I measure every variable of the piston's up & down stroke & determine within 0.0005 accuracy (half of one-thousandth of 1 inch) which combination of pads & shims are needed to achieve proper alignment. While I've developed special tooling & a specific method for measuring the instrument with such a high degree of accuracy, obviously it is not realistic to claim that number can be converted to the physical limitations of fabricated materials, nor is it a level of distinguishable significance. I can however guarantee a usable accuracy of 0.002 in any alignment I perform.
Valve Port Calibration refers to a different kind of adjustment where the existing pads/felts are measured & replaced with synthetic non-compressable felts. This is done when I player, who may already be in for service, expresses that they prefer their instrument exactly how it is in its current alignment, for better or worse. If they currently have in place traditional felts/pads, these will continue to compress & degrade from their current condition & size. Once this occurs to a large enough degree, the instrument will no longer be at the same alignment that the player once found optimal. Replacing those pads with more durable & more accurately made materials, at their current specifications, will maintain an ideal alignment, thus calibrating the valve ports for that specific player.