Turtlerock Forum

I just received my January edition of SOS and inside was an (SOS, in association with SAE) Audio Frequency Chart in the form of a poster. Whilst browsing over I noticed that A4 was 349.228 and not 440 like i thought. After researching whether they used a scale i hadn't learnt or they just made a mistake, I found out they claimed it was a "printing error" that the chart was wrong. They will be reprinting a correct one and supplying it with the Feb edition. As a former student myself, you have to trust that what you are learning is correct and I feel sorry for all the people buying that edition at the news agent who may not buy the next one that will be misinformed. I think its important that if you are earning your money by educating then you have a responsibility to be correct.
I do appreciate what both SOS and SAE do but I also think that kind of mistake is unacceptable. Rant over.

Yeah, although 349 is way off, A 440 is just the standard concert pitch for the western world. It can vary from 435 to 444, sometimes even more depending on the historical period or geographical location (you could argue also height above sea level, but that would be getting silly). Sometime you'll find classical samples/libraries that are flat to A440...

not that this has anything to do with it...but it reminded me..

When I was in the RAAF one of my jobs, was calibrating aircraft weighing kits. The use 4 load cells which they actually lower the plane onto...and the change in resistance, is calibrated to reflect weight...very cool
Anyways, I was in Melbourne at the time, and depending on where the kit was going in Australia, we had to factor in the local gravity of where it was going...which varies, and varied enough to effect the readings.....wild stuff. I think we used the latitude of the place it was going to ,and a chart that showed you the difference from Melbourne, but this is nearly 25 years ago, so some details are hazy.

We used what were called vernier rings, and a hydraulic press which the ring and the load cell were fitted into and then you jacked up the hydraulic press to up to 50,000 lb (if memory serves) this huge vernier ring jammed in the press balanced on ball bearings....like a silver marble one on top and one underneath.

back to your regularly scheduled program...8)

Peter

Whew - I thought they'd just devalued A440 along with the Euro.....

I think it's worth mentioning that A=440 is a completely arbitrary thing, like the length of a metre or the fact that we call a certain range of visible light frequencies 'blue'.

Not suggesting people here don't know that, but I do occasionally run into folks who seem think that A=440 is some fundamental fact of nature.

Lee, you have spotted one of many errors in the chart.

See here.
http://www.soundonsound.com/forum/showf ... t=1#960051

Manning wrote:I think it's worth mentioning that A=440 is a completely arbitrary thing, like the length of a metre or the fact that we call a certain range of visible light frequencies 'blue'.

Not suggesting people here don't know that, but I do occasionally run into folks who seem think that A=440 is some fundamental fact of nature.

The length of a metre is arbitrary?

JamesM wrote:

Manning wrote:I think it's worth mentioning that A=440 is a completely arbitrary thing, like the length of a metre or the fact that we call a certain range of visible light frequencies 'blue'.

Not suggesting people here don't know that, but I do occasionally run into folks who seem think that A=440 is some fundamental fact of nature.

The length of a metre is arbitrary?

Um, yes, in the sense that all conventions are arbitrary. The metre is not a constant of nature, it is an agreed convention, and it "official" length was decided by some Frenchmen in 1889.

Arbitrary -
subject to individual will or judgment without restriction; contingent solely upon one's discretion: an arbitrary decision.

I would say a meter is EXACTLY 100 cm and EXACTLY 1000 mm etc, it is an absolute measure no?

One metre is 100cm. You can't choose a different length and call it a metre. So in that sense, not arbitrary.

The choice of 100cm WAS arbitrary when it happened. For that French guy. For a regular man on the street it's not.


Is anyone else reminded of the episode of The Games about the 100m track?

Yes, but a millimetre is an 'arbitrary' length- eg, it's not 1 million atoms long (if atoms are even the same size!), it's just a made up length we all agreed on, not really based on anything except ease of use.

So Manning is just making the point that A4=440 is just a group decision on what 'in-tune' is, it's not based on any naturally occurring phenomena.
And A4 has moved a long way up over the past few centuries, from around 420 to 440-442 today.

edit- sorry Hud, missed your post.

I think the problem is that I am using "arbitrary" in the sense normally used in scientific language, not in common parlance.

Arbitrary - Determined by chance, whim, or impulse, and not by necessity, reason, or principle. (The Free Dictionary)
Arbitrary - based on or determined by individual preference or convenience rather than by necessity or the intrinsic nature of something (Merriam Webster)

In the scientific and mathematical world, arbitrary is typically used in the above senses, to distinguish from things which are "fixed" or absolute. The value of pi, e, the Gravitational constant, the speed of light are all things which are absolute, ie not arbitrary.

The length of the metre was not established by any "necessity, reason or principle", it was established by chance. The intention was to define it as "1 ten-millionth of the earth's circumference", but as that figure wasn't precisely known at the time (and it still isn't as the earth is an oblate spheroid and the transverse diameter varies with proximity to the sun), the resulting length was basically a stab in the dark.

Thus all systems of measurement are always based on mutual agreement to use an arbitrary reference, there are simply no absolute lengths.

As a sidenote, in the early 20th century there actually WAS an attempt to establish an "absolute" system of measurement. First they tried to base it on the diameter of the hydrogen atom but this was nixed by Planck with the discovery of energy shells. Then they tried the diameter of a proton or an electron, but Heisenberg nixed both of those with his uncertainty principle.

Hud wrote:One metre is 100cm. You can't choose a different length and call it a metre. So in that sense, not arbitrary.

Well actually you could. And if you managed to get enough people to agree with you, you could then change the currently accepted length. It's just incredibly unlikely.

Hud wrote:Is anyone else reminded of the episode of The Games about the 100m track?

That show was genius.

In an effort to clear up any inaccuracy contained in this thread thus far please refer to the video below, posted in the hope of clarifying any misunderstandings:
http://www.youtube.com/watch?v=vQU1AcWUnpo

Chris H wrote:In an effort to clear up any inaccuracy contained in this thread thus far please refer to the video below, posted in the hope of clarifying any misunderstandings:
http://www.youtube.com/watch?v=vQU1AcWUnpo

I just took a lunch break and watched the whole thing...was really great...thanks for posting that.

cheers

Pete

Ditto - I loved that.

and this month A=400

It should really be 432Hz...it would restore global harmony
http://en.wikipedia.org/wiki/Schiller_I ... rdi_tuning