Upright Canister Stove Reviews, StoveBench Tests, and Gear Guide

[Scott Chandler]

I’ve got a new topic for study — why piezo igniters fail or don’t work.

[David D]

A small correction but one that matters “The BRS 3000t also happens to be the loudest stove we tested, by a wide margin – we clocked it at 91 dB in a test group that averaged less than 80 dB – that’s right, the BRS 3000t is more than ten times louder than our average stove (because dB is measured on a log scale)!”

A 10 dB increase in sound pressure level is perceived as twice as loud.  So the BRS will sound twice as loud, not 10x as loud.  Not great, but not catastrophic.

[Jon Fong / Flat Cat Gear]

From the web, 

For example, every increase of 10 dB on the decibel scale is equal to a 10-fold increase in sound pressure level (SPL). Near silence is expressed as 0 dB but a sound measured at 10 dB is actually 10 times louder. If a sound is 20 dB, that’s 100 times louder than near silence.

https://www.healthyhearing.com/report/52514-What-is-a-decibel#:~:text=Decibels%20increase%20exponentially&text=For%20example%2C%20every%20increase%20of,times%20louder%20than%20near%20silence.

 

[David Hartley]

David D. is right – 10 dB is a 10x higher sound pressure level – but we don’t perceive it that way. Human perception of sound volume is closer to 2x for a 10 dB difference in level.

[Jon Fong / Flat Cat Gear]

Given that dB is a log scale, that does not make sense to me. Please elaborate.

[Roger Caffin]

Remember two things: the range of sound intensities is huge, really huge, and the ear ‘hears’ sounds on a log scale, not a linear scale. Why? Evolution I guess, to be able to handle the huge range. Loud rumble of rock fall (or predator scream), vs tiny rustle in the grass as the predator approaches.

Eyeballs are similar: the range of light intensities is also huge, and your eyes can handle that too. Bright daytime and starlight.

Cheers

[David Hartley]

First up – I messed up – posted too quick without thinking. While SPL is a base 10 logarithmic calculation, it is a 20xLog calculation, not 10xLog, so a 10 dB SPL difference is not 10x, it is 3.16x difference in sound pressure, and a 20 dB difference in SPL is a 10x difference in sound pressure. The Sound Pressure Level in dB is 20xLog(P1/P0) where P0 and P1 are linear pressure measurements and P0 is 20 micro-pascals). How embarrassing – nothing worse than a math error on a BPL posting!

Here is info on SPL: https://pressbooks.umn.edu/sensationandperception/chapter/loudness-and-level/

Anyway the 2x loudness for 10 dB SPL difference is a common rule of thumb in audio engineering. If you google SPL vs perceived volume there will be many links (e.g. https://www.engineeringtoolbox.com/sound-pressure-d_939.html ).

Most references I could quickly find state it as a good approximation, without references. It is more complicated than that of course because there are differences in perception based on the frequency of the sound as well. Also the ear is compressive at higher volumes. This being BPL, I will try and find a good documented study later.

[David Hartley]

This is probably digging way deeper than really worthwhile on this topic – the BRS-3000T is louder than the other stoves  – but maybe so what? Unless it really matters to you – then don’t use it. Its certainly not a risk to your hearing given the extremely short time period you would be exposed to it.

First, this statement in the original article is incorrect: “we clocked it at 91 dB in a test group that averaged less than 80 dB – that’s right, the BRS 3000t is more than ten times louder than our average stove (because dB is measured on a log scale)”. The Healthy Hearing website linked above by Jon Fong is also wrong for the same reason. A 10 dB difference in SPL corresponds to a 3.16 x difference in sound pressure (because an SPL difference in dB = 20 x Log (P2/P1) where P2 and P1 are the two sound pressures being compared). A 10x difference in sound pressure corresponds to a 20 dB difference in SPL.

Now as far as perceived volume or loudness – I found many places the 2x loudness vs 10 dB SPL difference was used and attributed to earlier studies, but with no actual references. This link (https://www.itu.int/dms_pub/itu-t/oth/06/17/T061700000D0002PDFE.pdf ) is an ITU slide deck on measuring loudness. Slide 11 shows that at 1000 Hz a 10 dB difference in SPL produces an approximately 2x change in Sone (a linear loudness measurement). Other frequencies have different slopes. What this means for a stove that is more like a filtered noise source? Who knows – more internet searching is not worthwhile.

Sorry if I took this too far – the 10x  for 10dB SPL difference mistake needed correcting.

 

[Roger Caffin]

My wife likes the stove noise. She sits at the back of the tent while I am at the front, with the food. To her the noise says ‘dinner is coming’. This is good!

And really, it is not a loud noise anyhow. Try one and see.
One of my Vortex stoves (which I make an sell) are louder, and their noise has never been a problem for any of my customers either.

Cheers

[David D]

10x the loudness would disqualify the BRS for many, 2x is an easier pill to swallow.

For any other sound nerds out there, perception of change in loudness is a pretty complex topic

A couple suggestions for future noise measurements, to compare with everyday sounds and put them into context:

• take the measurement a typical distance away. A sound source this small will decrease SPL ~ 6dB every doubling of distance away.
• use the “C” weighting on the meter for louder sounds, “A” weighting for quieter ones.  This can make a big difference in the outcome

Is the BRS SPL 91dB (C weighted) at a typical distance away?  That’s the loudness of a typical lawn tractor.

[Roger Caffin]

Is the BRS SPL 91dB (C weighted) at a typical distance away? That’s the loudness of a typical lawn tractor.
I have never measured the sound level, but I can say my BRS is nowhere near the sound of my lawn tractor! Far from it.

Cheers

[David Gardner]

The latest version of the BRS3000T (left) and its clones have thicker pot supports than the old ones (right):

Has anyone had a failure of the new pot supports?

[Roger Caffin]

Most interesting news. A fine tweak on the underside of the arms.
Thank you David.

Cheers

[Author]

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