The Highland Bagpipe is not a quiet instrument. Indoors, the Highland Bagpipe can reach a noise level of 122 decibels (dB). By comparison, a jet airplane taking off can reach 130 dB at 100 meters. Noise at 120 dB can cause hearing damage after short-term exposure. This reinforces the need for hearing protection when playing the pipes.
Fortunately, we have a quieter alternative. Practice chanters are significantly quieter than a full set of pipes. However, some practice chanter reeds can be relatively loud and can peg the meter at a noise level over 80 dB. Noise at this level, equivalent to busy traffic or an alarm clock, can be disturbing to your room- or housemates and can bring a neighbor in a hotel out of his or her chair to beat on the wall in order to admonish you to stop.
The goal of this post is to report on measurements that were taken after modifying a practice chanter reed to make it more quiet. The overall goal was to configure a practice chanter reed to register a noise level of 60 dB. This is the noise level for normal conversation. This would be an acceptable level so that a practice chanter would not disturb a room mate or a neighbor in a hotel.
We took initial, baseline measurements using an unmodified Chris Apps practice chanter reed in a full-sized, Colin Kyo, blackwood, practice chanter. We then took separate measurements in the same practice chanter using a reed that was modified by placing a dental elastic 2mm from the base of the reed. This modification is depicted in the following photograph:
A second set of measurements were taken in the same practice chanter using a reed that was modified with a wrap of 6mm thick acoustic foam (also known as anti-vibration foam). The modifications are described in this post. This modification is depicted in the following photograph:
For each reed configuration, two measurements were taken using the app Decibel X on an iPhone 7 using the built in microphone. One measurement was taken with the bell of the practice chanter placed 12 inches from the microphone on the iPhone. A second measurement was taken with the bell of the practice chanter placed 4 feet from the microphone on the iPhone. For each measurement, the first part of the 2/4 march "Australian Ladies" was played without a repeat. Only the first 169 observations in each measurement were used in the data.
The first table, listed below, summarizes the measurements at 12 inches for each reed configuration, unmodified, modified with dental elastic, and modified with acoustic foam.
Overall, the reed, when modified with a band of acoustic foam reduces the average noise level, but only slightly (6.9 dB). This modification, though, does bring the noise level of the reed closer to the noise level of normal conversation. The Chris Apps reed is somewhat quiet to begin with. One flaw in the methodology is striking in this data, however. Since we can control the noise level of the reed by increasing the pressure on the reed when we blow into the practice chanter, we see that each the peak for each reed comes close to the 90 dB level. As we breathe when we play, we may attack the note following a breath with more power, hence increasing the noise level.
The measurements at 12 inches approximates the noise level to which our ears are exposed during a session with the practice chanter. Overall, with acoustic foam, we reduce the average noise level to which our ears are exposed. However, we have spikes, represented by the MAX, which come close to 80 dB.
The second set of measurements, listed below, summarizes the measurements at four feet for each reed configuration.
These measurements approximate the noise level to which a roommate or a neighbor in a hotel would be exposed. In these measurements, the noise level of the reed modified with acoustic foam is close, overall, to the noise level of normal conversation. However, with the exception of the MAX, the reed modified with a dental elastic also comes close, on average, to normal conversation. Moreover, the unmodified reed, although slightly noisier than the other two, comes close to noise level of average conversation as well.
The MIN, MAX, and average are useful measurements. However, the following graph, which plots each of the 169 observations measured at 12 inches, illustrates the noise level to which our ears would be exposed. Although the reed modified with acoustic foam has a MIN of 52.0 dB, a MAX of 79.7 dB, and an AVG of 67.5, the consistent noise level is closer to 70 dB. The reed modified with acoustic foam appears to have fewer spikes, though, above the 70 dB level. In contrast, the unmodified reed and the reed modified with dental elastic have more spikes above their respective averages.
At four feet, we can begin to see the effect of distance on the noise level of each reed modification. The graphs for each reed modification show more variance but are, overall, lower in noise level. Both the reed modified with dental elastic and the reed modified with acoustic foam are close to the 60 dB noise level.
At four feet, the reed that was modified using acoustic foam met the goal of a noise level of normal conversation. The maximum recorded noise level was also close to normal conversation. Using acoustic foam to silence a reed certainly is a promising technique. On a personal note, during a recent trip, I practiced regularly using a reed modified with acoustic foam. The neighboring rooms in the hotel did not complain over a two-week period.
However, it should be noted that a reed modified with a dental elastic also performed at or near the level of normal conversation.
While this study offers some suggestions as to how these two methods, acoustic foam and dental elastic can be used to silence a practice chanter reed, we cannot offer this as definitive data. We only performed one trial for each reed modification at 12 inches and four feet. In order to arrive at more definitive conclusions, multiple trials would need to be executed. Moreover, this post only examines one specific type of practice chanter reed. It would be valuable to examine a larger, representative sample of practice chanter reeds.
In addition, a single practice chanter was used in this post. It would be valuable to examine different types of practice chanters. For example, a smaller practice chanter, with a cylindrical bore, can be silenced my moving a dental elastic almost to the tip of the reed.