So, there’s a debate going on whether sympathetic beating of the drone reeds leads to more stability in tuning. I say it practically doesn’t happen, but I won’t go there. Instead, here is a recording from inside the bag, just for giggles. Cool uh? or I guess for you Canadians, cool eh? :o) I don’t think the recording means a whole lot in the context of the debate, ah but whatever, you may draw your own conclusions.
A Father of Piping, Brian Barrow (from inside the bag)
My list of excuses:
This is about 8 minutes into a 9 minute practice session because it’s late and I actually wanted to go to bed instead, but I figured this would be interesting enough to warrant the loss of sleep. So, the drones aren’t in perfect tune, and they go out towards the end. Sorry about the high A crow at the end. My bad. Gannaway bag, Crozier Cane tenors, Kinnaird bass (the cane wasn’t stabilizing fast enough), in Gellaitry pipes with a carved up Naill chanter and a crowy reed.
A couple of clips of the scale played on the highland bagpipes with the low G substituted for another note. Low A is tuned to 480 Hz + ~10 cents.
Low F# – obtained by taping over one tone hole entirely and taping over the other a little bit for tuning. Grace notes to and from low F# sound and act fairly normal.
Low E – obtained by taping over both tone holes entirely and extending the length of the chanter just a little bit with a ring of tape on the very bottom, less than a centimeter in length. All the grace notes on the bottom hand work well enough, though throws and such don’t work very well. All the top hand grace notes produce a squeal.
Chris Apps poly chanter with a ridge cut reed. 1950’s Henderson pipes, Selbie drone reeds.
Below is a spectrum of a Colin Kyo pipe chanter with a McCann reed mouth blown. Interesting to see which notes contain what harmonics. Click the image for a bigger version.
I have recorded the bag, drones, and chanter with a contact mic and all produce easily visible spectra. I don’t have many pictures yet but below are 2 mp3 files. One is of the contact mic being placed on the outer part of the lower bass drone tuning chamber, where my head falls if I lean over. Another is a few tunes with the contact mic on the chanter, you can hear the pops when my fingers hit, the mic clamped between low A and the tone holes.
Below is a recording of a piezo (contact microphone) in contact with your bagpipe bag. It has 4 parts, depending on where I put the microphone. I am playing at low A = 440 Hz (MacLellan A440 chanter) and my drones are just slightly out of tune (a fact that I regret, sort of – it gives you an idea of how much one can hear from the piezo’s perspective if they are a little out of tune). Anyways, the first part is the piezo in between the blowpipe stock and chanter stock, right on top (bagchanter). The second part, the piezo is moved to in between the blowpipe stock and the drone stocks (bagblowpipe). The third part, the piezo is placed underneath the bag, behind the chanter (bagbottom). The fourth part is my reaching behind me and putting the piezo on the back of the bag (bagback). The chanter is playing high A the whole time. I play a Medium Swan Monarch Synthetic bag with a TrueFit cover. The drone reeds are MG bass and Selbie tenors. They all are attached to the drone reed seat via an extender to tune low enough in pitch to play with the MacLellan A440 chanter. Thus, the drone reeds slightly poke out the end of the drone stocks, which may have a huge effect (or no effect), on how much sound is contained in vibrations of the bag.
Here is a frequency analysis of all 4 positions with no normalization.
Click on any of the pictures to get really big versions of each.
I have recorded the sound of my tenor drone with varying lengths of the slide. 1950’s Henderson tenor drone, Selbie drone reed. Limits of this study are the resolution of the FFT analysis produced by Audacity using the Hanning window. Below is a graph of the pitch of the tenor drone from the FFT analysis and Audacity “change pitch” function. Agreement is okay/good.
Below are 3 graphs of the FFT analysis. The numbers on the right are how long the exposed tenor drone slide is measured in millimeters, mm. The note (in the bagpipe convention) is given over the lowest pitched tenor drone (longest exposed tenor slide – a yellow/brown colored line). The 2 longest exposed tenor slide recordings have an ‘h’ next to them indicating that hemp is exposed. Note that at E*, the harmonic spectra overlap, looking at spectra beyond the 3rd graph will give you a headache! All the spectra are normalized in such a way that the fundamental has a value of 1 dB. This is because it is ‘impossible’ to ensure that each recording captures the same volume from the drone for each different slide length. This is the only way to draw any conclusions from the changes in amplitudes of the harmonic spectra that accompany changes in tenor drone slide length (proportional to the length of the tuning chamber).
The left-most ‘A’ on the top graph below is the fundamental of the tenor drone.
Remember, dB is a logarithmic scale!
Amended May 5, 2011:
I also tried this on a Naill tenor drone with a Wygent reed and got the same results (it’s not normalized but the effect is easily visible):