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You know when you have a good idea, but don't have the time or resources to actually do it? Well, here's an example... Cue: picture...
Photo by Kelly Sikkema on Unsplash |
You have probably noticed that just about every electronic musical instrument makes a different noise when you press and release the keys on the keyboard. Some are quiet, and you barely notice them. Some are noisy and intrusive in some circumstances. Some make springy sounds. Some make a sort of clacking sound. Some are so jarring that you have to use headphones or turn the amplifier up. Some are an intrinsic part of the instrument (acoustic piano, clavinet, harpsichord...). Some defy description. Everyone has their own preferences for what is an ideal 'noise', or lack of it.
But what is difficult to determine is what an instrument will sound like - in advance. In general, and especially in these 'online purchase' times, it is only when it arrives that you actually get to hear what the keyboard actually sounds like, especially long-term. Even a few minutes in a music shop may not give you a very good idea of how it will sound in your acoustic environment.
So I gathered some keyboard noises from a few instruments: high velocity key-down, and high velocity key release. This is what I got (time waveforms at the top of each set, spectrograms underneath in colour):
SY99, Montage 7, and CLP-930 key noises |
These weren't perfect recordings. But what is intriguing are that they key-up is sometimes louder than the key-down (SY99), and that there are wide variations, particularly the Clavinova (echoes from the cabinet, or scrapes from the action?). You will eventually be able to get edited versions of my recordings here.
This topic came up recently on the VI-Control Forum, a place where composers, musicians and technologists with an interest in virtual instruments (Kontakt et al) discuss a variety of topics. In this case it was specific to MIDI Controller keyboards, but the subject of keyboard noise is really a generic one across all electronic musical instruments with keyboards. I proposed that a crowd-sourced approach to gathering the sounds might be a way to get some useful material (by asking VI-Control Forum members to record their keyboards), although I acknowledged that there were some problems to overcome. There wasn't much feedback, and this often happens in forums - they aren't really places for marshalling big campaigns involving lots of people, unless there's a very strong reason that will motivate people.
Since then, I've been thinking about it a bit more, and I decided that an alternative way of gathering the data could be an interesting experiment. I am sure that it is a good idea, and that the results will be useful, but I don't have the time to do it myself.
So I have written up some more of my thoughts and the background research that I did around the idea, and have produced a rough Project Proposal. That's what follows. My hope is that a university or college student on a music technology course, or maybe an intern at a manufacturer, sees it, and decides to do the research and then publish it. If you know someone who might be interested, then feel free to give them this URL or the project proposal below!
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Title: Noises in the Keybed.
Abstract: The keys on the music keyboards (keybeds) on electronic musical instruments make noises when they are pressed and released. Data on the Sound Pressure Levels (SPL) of these noises, as well as subjective descriptions, and recordings of the sounds that are produced, are not widely available. As a result, it is difficult to make informed decisions when deciding which instrument to use for a particular application. This project aims to provide information on how relevant data can be captured consistently and reliably, and subsequently made available to anyone who would find it useful.
Procedure: There are several stages required to capture relevant data of the noises made when the keys on a music keyboard (on an electronic musical instrument or MIDI Controller keyboard):
1. Preparation of the keyboard, the recording/measuring equipment, and the performer.
2. Key-down noise (pressing the key on the keybed, from the default 'rest' position, to the full depressed position, where it is stopped by the physical keybed)
3. Key-up noise (releasing the key on the keybed, so that it returns to its default position)
4. Processing of the captured audio files and SPL levels
5. Processing of data from the processed audio files
Stages:
1. Preparation.
The capture can be carried out by individuals acting as part of a crowd-sourced team, where the results are collated by an individual or a team. Alternatively, the capture can be carried out by a single individual or a team.
The keyboard should be placed on a solid surface, ideally one that is free of rattles, creaks and other noises. The 'performer' should checking for any variation of noises across the range of the keybed, and then choose the noisiest key as the one to use for SPL measurement. If the noise is consistent across the keybed, then a key in the middle of the range of the keyboard should be chosen. Whichever key is chosen, it should be marked with a removable sticker, and this will then be the only key used for the capture.
If a microphone is used then it should be placed 1 meter vertically above the keybed. This makes positioning easier than close mic'ing. Because the source of the sound is typically inside the keybed, then positioning the mic above the keybed (and with the microphone) aimed at the keybed, should capture the sounds produced by the keyboard, and should not interfere with the pressing and releasing of the keys on the keybed by the 'performer'. This positioning of the microphone should be possible with most mic stands.
If an SPL meter is used then it should be placed in the same way as the microphone: 1 meter vertically above the keybed.
Low-cost SPL Meters. You 'can' get cheap (about 20 USD) SPL meters from Amazon et al.., but their supplied calibration is difficult to determine, there is anecdotal evidence that indicates that measurements may be several dB different relative to a properly calibrated SPL measuring device, and proper calibration devices cost about 6x that (about 120 USD). This approach seems to be a recipe for making the results worthless because of lack of calibration - but may be the only apporach that is feasible when using crowd-sourcing.
Higher-cost SPL Meters. Properly calibrated and calibratable SPL measuring devices will typically cost over 120 USD, and will require the use of a calibrated sound source (about 120 USD). The same SPL measurement device should ideally be used for the whole of a session, and ideally for as many captures as possible.
Capture measurements should be of SPL and the sound simultaneously, and so a microphone and SPL meter should both be positioned 1 meter vertically above the keybed. They should not touch. One possible alternative to using separate microphone and SPL measuring device (meter) many be a calibrated USB microphone. One example is: https://www.minidsp.com/products/acoustic-measurement/umik-1. These cost about 120 USD, but can be used to capture both the audio and a calibrated level for the audio (it may be possible to also derive the SPL).
The recording environment should be as quiet as is practical. A 30 second recording of the background noise in the recording environment should be made at the beginning and end of each capture session, so that the recording can have noise reduction applied, if this is required. The ambient temperature in the recording environment should also be noted at the beginning and end of each capture session.
The instrument, of which the keyboard is a part, should be set so that it does not make a sound. For electronic musical instruments this generally means that it should not be connected to an amplifer, or the internal loudspeaker amplifier should be set to minimum volume. For other instruments, then damping may need to be applied to any vibrating part that is not directly a component of the key mechanism.
The performer, whose role is to press the key on the keybed at five second intervals during the capture session, should wear cotton clothing, a sleeveless tee-shirt, no jewelry, no rings, no bracelets, no ear-rings, etc. Ideally, they should wear no metal or other material that could make any extra noise. The only noise that should be recorded is the sound of the key on the keybed. The performer should breathe quietly and moderately during the capture session.
It may also be possible to find data on the SPL of keybed noises on the InterWeb, although the author has not found any such data. A search for this would be good practice before committing to a full project.
2. Key-down noise
The performer's task is to press the defined 'middle' key on the keybed, moving it from from the default 'rest' position, to the full depressed position, where it is stopped by the physical keybed. The start of recording should be indicated to the performer, who then waits 10 (ten) seconds, and then presses the key. Once pressed, the performer then waits for 10 (ten) seconds, and then moves to the next stage ('Key-up')
A range of velocities or strengths, of pressing the key should be used. The minimum set should be High (as fast and hard as possible), Low (as slowly and lightly as possible), and Mid (mid-way between the previous values). If MIDI is available, then MIDI velocity can be used to achieve consistency. Max would have the MIDI velocity value of 127, Mid 64 and Low should be below 30, but this depends on depending on the playing ability of the performer.
Notes should be taken during the capture session as a subjective record of the 'sound' of the key noises. Words used can include: clicks, snaps, clunks, thumps, spring-buzzes, slides, sizzles, etc.
The three MIDI values:127, 64 and 10-30 should capture most of the variation of 'sound vs velocity', and a single key is not onerous to record: less than 30 seconds of WAV, and probably less than a quarter of an hour to accomplish. If it is discovered that there is a particular velocity or strength of pressing that produces a different opr louder noise, then this should be captured and noted.
Three key-down captures should be recorded.
3. Key-up noise
The performer's task is to release the key on the keybed, so that it returns to its default position. Based on the techniques used to record acoustic pianos, then there are two extremes that should be captured:
a. Starting from the key being held down (the ending position of Stage 2), then the performer moves their finger backwards so that the key is allowed to rise up to its default position on its own. The performer should strive to avoid making any noise as the key is released.
b. Starting from the key being held down (the ending position of Stage 2), then the performer moves their finger upwards and off the key as quickly as possible, allowing the key to rise up to its default position on its own. The performer should strive to avoid making any noise as the key is released.
Once the key has been released, the performer should wait 10 (ten) seconds before the next Stage 1 key-down, or if this is the third capture, then the performer should wait 10 seconds and the capture will stop.
Three key-up captures should be recorded in total per chosen key on the instrument. If one key has been chosen, then three captures. If two keys have been chosen (noisiest and quietest, where there is a noticeable range of noise levels), then two sets of three captures should be recorded in total.
4. Processing of the captured audio files and SPL levels
The recordings of the key-down and key-up events stages (2 and 3) will be in pairs (down then up), and there will be three contiguous sets of the pairs. Each stage should last for ten seconds, with an extra 10 seconds at the start.
The audio files can be trimmed so that there are 10 seconds of near-silence before the first stage 1 capture, and 10 seconds of near-silence after the third stage 2 capture. The audio files should be stored in a linear, uncompressed format. WAV files, either 24 bit or 32 bit floating point, ideally at 48 kHz sampling rate. 44.1 kHz can be used if it consistent across all captures. Mixtures of 44.1 kHz and 48 kHz sampling rates should be avoided if possible.
If an SPL meter is used, then the peak measurement during the three captures should be noted.
Files should be saved with names that include the date, instrument name, a capture session ID, the sample rate, and the bit depth (24 or 32float).
5. Processing of data from the processed audio files
A spreadsheet should be used to hold the metadata noted during the capture session. Columns should include the date, instrument name, a capture session ID, the sample rate, the bit depth (24 or 32float), the measured peak SPL, the name of the performer, the name of the recording engineer or co-ordinator, any notes (quiet, noisy, clicky, thumpy, etc.) and any other comments.
A cloud-based spreadsheet is recommended. Airtable is a sharable spreadsheet with advanced capabilities that offers a free service for small numbers of rows in the spreadsheet. https://airtable.com/
Stages 4 and 5 are just spreadsheets, and file management, and will appeal to a very particular type of person.
The results should be shared as widely as possible. The VI-Control Forum is one possible place where a post could be placed.
Conclusions: I hope that this project proposal is useful to someone. Please feel free to share the URL or a printout of it to any researcher, student or intern that might find it useful or inspiring. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License, so that it is available to all under clear usage terms.
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So, there I was, working away in the studio, when I noticed some black dust on the keyboard of my Yamaha SY99 on my keyboard rack. I looked at the Synthstrom Audible Deluge above it, and moved it a little, and more black dust appeared. What?
The Black Dust! |
The dust is dark black, gritty, and very fine. I have no idea what it has been doing to my synthesizer keybeds or key contacts... I have to say that this isn't a complaint - after over 30 years, then I would expect some deterioration of some components, and everything else about the rack is still perfection!
After some investigation, it turns out that the rubber pads on the keyboard support brackets on my custom hand-built Ultimate Support Systems rack have perished over the last 30-odd years, and need replacing. (As an illustration of how things have changed over those intervening years: Ultimate now only seem to make those stage-friendly 'Z' and 'X' shaped stands... http://www.ultimatesupport.com/products/keyboard-stands.html )
Just removing the support brackets created dust! |
Fixing the problem requires pulling apart a five-tier custom keyboard rack ( the modern equivalent would be something like https://www.jaspers-alu.de/aid-677-KR170-4-150B.html ), removing the keyboard support brackets, removing what's left of the pads, then removing the 30-year-old adhesive (nasty and difficult), then putting on new better pads, putting the keyboards/synths, drum machines, sequencers, mixers and stuff back, then cabling it all up again - not quite a five minute job.
The rubber pads are now very fragile... |
As you can probably sense, it's all a bit fraught here at the moment, and I have no idea how much damage that black dust (gritty, abrasive, horrible stuff) has done to my keyboard contacts and keybeds. Vintage gear, eh? You think that all you have to contend with are LCD backlights failing, or electrolytic capacitors drying out - and then you get awful black dust everywhere. I'm just glad that I have spotted it, that I don't move stuff around on the rack very often, and that I don't have any of those amazingly expensive synths that you see on eBay and Reverb. I'm also guessing that there may be more than a few other synthesiser owners who haven't checked the rubber pads on their more-or-less permanently-installed keyboard racks for quite a while... Now could be a good time to check. It did seem that, as with 19 inch racks, heat may be a major contributor to problems - the worst deterioration did seem to be where the synth/sequencer/drum machine/etc., got warm...
The support bracket, the gripper bracket, the bolt and an Allen key... |
Some mechanical details are probably a good idea here - because the modern racks from people like Jaspers are different (Yep, in more than 30 years, designs have changed!). The basic tubing of the rack is black anodised aluminium: 38 mm in diameter. the gripper clamps/brackets use an Allen key to tighten them in place by gripping the tube, and a pozidrive bolt holds the support bracket onto the gripper clamp/bracket. As you can see, there's a design problem with the gripper clamp/bracket - it is in one piece, and so can only be removed by pulling almost the whole keyboard rack apart (in most cases!). That is a lot of dismantling! A two-piece gripper clamp/bracket would be a much better design...
The black dust removed from a support... |
After two days pulling my keyboard rack gradually apart, and then attempting to get the rubber pads off, I now have a much better idea of what is involved, and I also have a lot of black dust...
Chemical failure... |
The adhesive is the worst part - after more than 30 years it is almost part of the metal. I've tried scraping at it, Fairy liquid, various degreasers, orange oil (my secret weapon) and a scary adhesive remover that is covered in warnings and is apparently toxic, flammable, harmful and more. None of them shifted it. As usual, take care with chemicals: read the warnings, do it in a well ventilated place (or outside) if recommended, etc.
So I stopped the arms race of ever-more-scary chemicals, and went old school. Time.
After soaking overnight... |
Yep, there are very few things that a little time won't degrade - as shown by the rubber pads! So I soaked them overnight in a hot dilute fairy liquid solution. Fairy liquid, or your alternative favourite washing-up liquid, is designed to do degreasing and a few other useful dish-washing tasks, but the important ingredients here are time, and water. Water is a strange liquid. It has all sorts of properties that are unusual, and it turns out that the more you investigate it, the more interesting it becomes. Anyway, the recipe, again, is water, time, and heat to help reactions along a little. Let's pause here overnight, and maybe another overnight...
Scraped off and allowed to dry... |
So, when the adhesive remnants have changed colour (paler, less saturated colours, and a milky appearance), then things have probably got a lot easier. After two overnights, then the remnants of the adhesive can be scraped off very easily using a screwdriver or an old credit card (another secret weapon). This leaves just a few bits, which I soaked again overnight.
Finally! Clean to my satisfaction! |
I was now starting to see some progress, and after drying them, then one of the 'not quite as alarming warnings' spot cleaner got me very close to a clean metal surface. And a final wash and dry got me to a final look that I was happy with, and one that was suitable for the new clear rubber stick-on pads that should apparently last for 50 years.
Just before reassembly and sticking on the new pads... |
If anyone had told me that the 25mm square rubber pads on my keyboard stand were going to be such a major problem, I would never have believed them. Amazing. I'm dreading opening up the keyboards to see what I find inside.
Brackets with new rubber pads... |
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Previously I've blogged about ' Waivy' , the simple swept wavetable glimpse into the forthcoming update to Waverne. Well, as ...