How loud and soft tubas play!

[Wyvern]

I have recently bought a decibel meter and out of interest decide I would try comparing my various tubas to see how loud or soft I can actually play them. I measured each in different registers at the loudest (ff), or quietest (pp) I could manage sustained with a good tone and pitch.

Of course the figures are just what I personally achieved in my practice room and factors such as differing acoustics would no doubt produce different results, but I still think provides an interesting comparison. If only to verify my suspicion that size and volume are not directly related when it comes to tubas.

Surprising that the PT-15 F could produce similar,or even greater volumes than the Neptune in all but the lowest register, the PT-3 was loudest up high, and in the cash register the Cerveny Kaiser could play the quietest, but was only loudest in the very lowest register

[Jack Denniston]

Interesting post- thanks.

A couple questions-
1. Are these differences significant, or for all practical purposes, to the average listener, would the ff and pp volumes sound about the same, from one tuba to the next, in all registers?
2. What about projection? Is it true that some tubas project the sound better than others? If you put the decibal meter at the back of a large hall, would these results change?

[Wyvern]

A couple questions-
1. Are these differences significant, or for all practical purposes, to the average listener, would the ff and pp volumes sound about the same, from one tuba to the next, in all registers?
2. What about projection? Is it true that some tubas project the sound better than others? If you put the decibal meter at the back of a large hall, would these results change?

1. I actually found quite significant differences from note to note on just one tuba and the figures given are the loudest, or quietest in that range. So one could not maintain quite the decibel level given if playing a scale. For practical purposes differences in volumes from one tuba to the next largely do not seem significant.

2. I just was trying out with a Db meter on my music stand in my practice room, so it tells nothing about projection out into the hall. However it is interesting that although the levels recorded for the PT-15 F are significantly louder in medium/higher register than the 2040/5 Eb, from recordings I have made using my Zoom H2 (in the last few months I have recorded all my concerts), the Eb definitely seems to project more out into the hall playing with orchestra. The decibel levels are interesting, but actually recording oneself from out in the hall is much more useful as a musical assessment tool. The thing with measuring decibels is that it does not take into account the differing harmonic profiles of the sound *, so I guess that could explain it being not directly related to projection?

One thing I did not mention in original post is that for short sforzando notes I could easily hit 126 Db in some registers, the maximum the device could register (!!!), but that would quickly diminish. So remember the figures given are for notes sustained over a couple seconds.

* I have some software to analysis sound profile which I got from an elephant communication researcher, so that will be my next experiment

[Dean E]

Interesting report. Did you select a particular filter setting on the meter?

FWIW, a chart of dB levels for musical instruments, and other common noise making activities, is at http://www.gcaudio.com/resources/howtos/loudness.html" target="_blank" target="_blank .

No tubas are listed, but trombones produce in the range 85 - 114dB.

Tymp and bass drum produce at at 106dB. The chart's footnote claims, "One-third of the total power of a 75-piece orchestra comes from the bass drum."

[Wyvern]

Interesting report. Did you select a particular filter setting on the meter?

The meter has two setting;
A = 500 to 10,000Hz for which the human is ear has greatest sensitivity
C = 32 to 10,000Hz to give an overall indication of sound level

I chose the setting of C to cover the tubas lower frequencies.

Interesting comparison with that chart you linked. However I would rather question the trombone having a decibel maximum only 3 Db higher than a cello. As I have recorded 120 Db on tuba, then I rather think a bass trombone can equal that!

[eupher61]

Projection and sheer volume aren't necessarily equal. Projection is more reliant on the color of the sound, and how a space amplifies the harmonics within the color, than pure sound pressure.

[Rick Denney]

A couple of comments come to mind:

1. This is a dB scale, which is logarithmic. That means that every three points on the scale represents a doubling or halving of the sound level depending on the direction. And I recall studies indicating that it takes about that much change to be a noticeable change to the listener. Thus, the difference between, say 109 and 112 dB is significant (if the measurement precision is adequate, of course). That also means that it takes twice as many musicians making the same sound to raise the scale by 3 dB. So, if Jonathon makes 109 dB, two of him would make 112 dB, and it would take four to make 115 db, 8 to make 118 db, and 16 to make 121dB.

2. The dynamic range of 30 dB seems quite large. A recording that can portray a single person playing softly would need 30 dB of additional dynamic range to reproduce that one person playing loudly. And another 20 or so dB to reproduce an orchestra playing loudly. That would be 50 dB of total dynamic range, and we used to listen to recordings that had only a little more dynamic range than that build into their technology. If, say, a viola playing softly (Mike--it could happen) produces a sound pressure level of more like 75 dB, the dynamic range probably exceeds all recording technologies except compact disks.

3. All of these levels are in the range that will cause hearing damage if sustained. But it begs the question for Jonathon--where was the meter? If it was directly in the blast zone, then it should be noted that the sound pressure will drop very significantly between there and the conductor, and off-axis. The reason for the claim of the bass drum putting out 2/3rds of the power of the whole band is that its sound radiates fairly equally in all directions, while instruments with bells provide considerable directional gain.

We had to play our last concert on a small stage, and the cymbal was right behind my head. THAT will NOT happen again.

Rick "doubting he could produce so wide a dynamic range" Denney

[Wyvern]

But it begs the question for Jonathon--where was the meter?

The Db meter was standing on my music stand in front of me (for easy reference), so not directly in the blast zone for a tuba. The sound must be reflective sound off the walls and ceiling of my practice room which is 20" x 10" with 6-9" slopping ceiling (I point the bell at the higher ceiling) and cannot have been much different from what I was hearing behind the mouthpiece.

How much difference the Db would be in a large hall from a distance I cannot say, although the tuba being of low pitch seems to suffer less fall-off over distance than most instruments and less directional effect. I would need to find myself a large hall and helper to find out the resulting Db level to the audience.

I do question the assumption that two players would mean double the volume, etc. I remember reading previously that that is not the case and if pitching is not perfectly aligned multiple players can in effect partially cancel each other out. When you think of it, a section of 32 violins is not 32 times louder than one solo violin.

[Rick Denney]

No, 32 violins are not 32 times louder than one violin. You can't tell the difference between 31 and 32 violins. But 32 violins should sound five times louder than 1 violin, at least theoretically, because one doubles the sound output five times to get from 1 to 32 (i.e., 2^5=32, or 15 dB).

And I'm assuming everyone's in phase. That should be true for professional brass sections, or at least the portions that are in unison. It's probably not true with the strings, who are covering that up with vibrato.

But mostly it was an explanation of how dB works and what it means--3dB is a doubling, which is "noticeably" louder.

And though I don't recall any details, I seem to remember that low frequencies don't cause long-term hearing damage the way high frequencies do, short of damage caused by concussion transients.

Rick "who'll tolerate a bass drum all day long before cymbals" Denney

[Wyvern]

But mostly it was an explanation of how dB works and what it means--3dB is a doubling, which is "noticeably" louder...And though I don't recall any details, I seem to remember that low frequencies don't cause long-term hearing damage the way high frequencies do, short of damage caused by concussion transients.

Rick "who'll tolerate a bass drum all day long before cymbals" Denney

Very interesting Rick. I did not know that 3 decibels doubles. I also kind of remember that low frequencies don't cause the hearing damage (lucky for us tuba players!)

I also hate to be anywhere near the cymbals and actually carry around musician's ear plugs to protect my hearing when unavoidably in that situation.

[SRanney]

And I'm assuming everyone's in phase.

While I am not a acoustical engineer, I learned (albeit a long time ago) that to be in phase, two or more people must be playing at identical frequencies. Identical. Even in professional brass sections playing in unison, how often do you think this happens?

[kingrob76]

You can't tell the difference between 31 and 32 violins.

I can tell. The latter requires more ammo to sufficiently address their intonation issues.

[Rick Denney]

You can't tell the difference between 31 and 32 violins.

I can tell. The latter requires more ammo to sufficiently address their intonation issues.

Hey, I said Jonathon can't tell. I wasn't talking about you.

Rick "scared of Rob" Denney

[DonShirer]

Although decibels are a common measurement of sound pressure level (SPL), they are not a measurement of perceived loudness. For that, acousticians use the unit of a phon (loudness level) or the sone (loudness). The sone has the advantage of being additive, i.e. a sound of 2 sones plus one of 3 sones give a perceived loudness of 5 sones. Both are frequency dependent: At 1000 Hz, a change of 10 phon is equivalent to 10 db, but 30 Hz it is a change of about 5 db at moderate sound levels. 40 phons is arbitrarily set equal to 1 sone, and increasing the loudness level by 10 phons, doubles the perceived loudness (i.e. to 2 sones). So it takes 10 violins (playing at the same level) to sound twice as loud as 1 violin.

A just noticeable difference of SPL is about 1 db for very soft sounds and about 1/2 db for loud sounds in the tuba range of frequencies according to published tests. However, in a actual performance situation with the distraction of many different instruments playing, Rick may be right to say that it would take a bigger change, maybe 3 db to produce a noticeable change (less than double) in loudness). Many experts quote the width of a musical dynamic level (ff to f, say) is about 6 db, so a total range of about 30 db is necessary for 5 dynamic levels (Rick's soft to loud range), for an intensity change of about 1000:1. However a 1965 study showed that many good musicians can only produce ranges of less than 15 db, with the woodwinds being the worst off. At that rate, Neptune's average 30 db range between pp and ff for a tuba is pretty good!