I bought a Radio Shack sound meter a few weeks ago. It cost about $50.
Richard Hawkins (Oberlin) mentioned he uses it to teach his students air and tone control. I also read about it in a recent issue of Clarinet magazine, in an article by Larry Guy (Vassar).
If you want to get one, be sure to get the digital version, as shown in the photo at left. It also has analog readout.
I have been working extensively with it, and I have to say, it's quite challenging to do longtones with it.
As suggested in Larry Guys article, I set the reader to 80, fast response, C weighting, for the lowest notes on the clarinet, from low E up to C.
With the reader set at 80 Db, it reads from 70-90. Below 70, it measures "lo" and above 90 it just blinks.
I began a long tone on a low E, trying to register only 70 before attempting to crescendo up to 71, then 72, remaining on each decibel for a few seconds.
In addition to the numbered digital read out, there is an analog type meter under the numbers. I found this quite useful. Watching the analog meter, I can see it bouncing around at the low end, and it give clues as to how controlled the tone is. It also helps me gauge the progress better than the numbers, because it anticipates the digital readout slightly.
I usually run out of breath by the time I get from 70 to 75, if I get that far. (this all became easier with time) So I breathe and attempt to begin exactly at 75, from which I increase to 80, then breathe, etc, until I reach 90. The start at 90 and diminuendo in stages until I am back at 70.
As recommended by Larry Guy, I also suggest moving the meter to 90 starting around low C and up, since those notes are automatically louder and it's almost impossible to control them at 70 Db.
Another variation is to begin the longtone at 75 (or 85 when using 90 as the setting), and crescendoing to 85 (or 95). This is plenty difficult, and will allow you do practice more longtone notes.
It's interesting how much more "crescendo" seems necessary to increase volume at the higher decibels. This is not only because it takes more air speed and strength to play up to 90 Db. It's also due to the way Dbs are measured. Below is a rough description of how much increase in power it takes to increase 10 Db. (here is the source of this information.)
On the decibel scale, the smallest audible sound (near total silence) is 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence is 20 dB. A sound 1,000 times more powerful than near total silence is 30 dB. Here are some common sounds and their decibel ratings:
* Near total silence - 0 dB
* A whisper - 15 dB
* Normal conversation - 60 dB
* A lawnmower - 90 dB
* A car horn - 110 dB
* A rock concert or a jet engine - 120 dB
* A gunshot or firecracker - 140 dB
You know from your own experience that distance affects the intensity of sound -- if you are far away, the power is greatly diminished. All of the ratings above are taken while standing near the sound.
Any sound above 85 dB can cause hearing loss, and the loss is related both to the power of the sound as well as the length of exposure. You know that you are listening to an 85-dB sound if you have to raise your voice to be heard by somebody else. Eight hours of 90-dB sound can cause damage to your ears; any exposure to 140-dB sound causes immediate damage (and causes actual pain).
Distance from the meter is another critical factor in how it reads. If it seems ridiculously sensitive, I move a few inches further away and try again. Just a small increase in distance will change how "loud" the sound is to the meter. Another factor to consider is what acoustical backdrop is behind the meter. (The meter points away from you, since it was designed to be used by someone to measure other sounds, not your own. But this doesn't affect its usefulness for longtones.) I place it on a music stand, almost at eye level, so I can read the meter without compromising my posture for playing.
Now we get to critical factors in how to control your tone.
1) It is important to remain relaxed and poised as you focus on controlling the air and tone. Try to find a position that you could stay in comfortably for awhile, without slouching. I prefer to stand while practicing. But even while sitting, feet should be "calmly" flat on the floor, knees and hips relaxed, head floating forward and up, neck free, back ribs relaxed and open to air.
2) When "taking" a breath, think of "letting" the air in, especially if you have squeezed the last bit of air out in your longtone.
3) Let the air in while keeping your neck, back and shoulders relaxed. Too often we try to suck air in while straining the neck and back. (and throat!) A good full breath will feel like it fills the space from your seat to to the base of your neck.
4) To control the release of air, think of holding the air with a "full tank" as if you are inhaling a little more, sort of an "open" feeling the air. Then release ever so slowly, pretending to fog a mirror one molecule of air at a time. It really feels like one molecule at a time, especially when you see how little air it takes to make 70 Db of sound!
Remember to keep your neck, shoulders and back relaxed throughout all this "control". What you are controlling is the motions of breathing, not stopping the air.
We are lucky to have such valuable technological tools to help us master the clarinet. Use them!
If you are interested in learning more about the science of measuring sound in Decibels, see THIS article.