how would you use an oscilloscope to measure a sine wave?

[Tim R]

There is an old paper where a musician claims to have used an oscilloscope to measure a particular trumpet tone and proved it was a pure sine wave. There is no date available but probably late 50s, the company was started in 1956. So we're talking whatever scope technology would have been available then.

I've always been a bit skeptical about the claims because there are some other aspects that don't make sense to me.

However, my question is about how you would use a 1950s era scope to determine a sine wave or the degree of harmonics present. Most musical tones have a series of harmonics above the fundamental that add the characteristic tone.

[gghe...@gmail.com]

Seems doubtful, I mean I can play a pure sinewave into a speaker and I know
what that sounds like. A trumpet sounds different.

George H.

[Ralph Mowery]

"Tim R" <timot...@aol.com> wrote in message
news:08de2443-cf3c-4789...@googlegroups.com...

An easy way would be to use a high pass filter or a notch filter to filter
out the frequency of the note and then look to see if anything is left.

Look for a SINAD or distortion meter.

When you filter out the origioinal wave (first harmonic) anything that is
left is from a frequency that is not the sine wave.
It could be distortion or a harmonic. The scope could be used to determin
what frequency or which harmonic is left over.

[Phil Hobbs]

Well, given that the trumpet is driven by a relaxation oscillation of
the player's lips, it would be quite strange if there weren't a lot of
harmonics. Odd harmonics would be nearly resonant, I think, though the
shape of the bell means that the resonance isn't really an organ-pipe mode.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

[c4urs11]

On Tue, 22 Dec 2015 05:59:52 -0800, Tim R wrote:

> However, my question is about how you would use a 1950s era scope
> to determine a sine wave or the degree of harmonics present.

Scopes from that era easily reached several MHz of bandwidth.
That should be considered adequate to inspect audio signals.

Cheers!

[Phil Hobbs]

The eyeball is a really lousy detector of harmonics, though, especially
odd harmonics.

Plus he had to use a 1950s-era microphone, so the scope bandwidth is
irrelevant.

[Tim R]

I've used an RTA, but those hadn't been invented yet. Before my time, but wasn't there something called octave filters?

The experimenter wasn't real detailed but supposedly he could tell from looking at the scope that it was a pure sine without harmonics. I was very skeptical that 1950s technology allowed that. He is a believer that the material a trumpet is made from determines the sound, whereas many of us believe it is the shape of the air column.

I will quote the article:
******
At one time we ran an experiment in which we used steel, aluminum, various plastics, glass, silver, various combinations of brass and the last one we used was lead. To demonstrate results as quickly as possible, I will choose the two extremes. The steel bell, which we tempered so it was extremely hard, gave possibly one of the most interesting results. Many people test a bell by tapping it with their finger or knuckle and in tapping the steel bell, it would emit a very ringing sound, truly like a bell. However, when we played this instrument, the quality of sound was extremely dead. On searching for the reason for this, we looked at the oscilloscope when the performer played on the instrument and found the sine pattern very faint but the distortion pattern, coming from the vibration of the bell itself, going through at a very jagged and rapid rate, killing the brilliance of sound of the true tone. At the other extreme was the lead bell. This bell, if rapped with your knuckle, emitted an extremely dead sound like rapping on a piece of wood. However the sound that emanated when it was blown was extremely brilliant, brilliant to the point of being mechanical. This showed up on the oscilloscope as a perfectly true sine pattern, there being no distortions in the harmonics either above or below, and, as a result, the sound was absolutely pure but not usable musically, except for a general effect such as a percussion instrument would give. The voice, you know, registering on an oscilloscope, gives harmonics both above and below the note. These distortions, if we may call them such, give warmth to the tone. We have to have that "distortion" in order to have the sound acceptable to our ears as a musical sound.

[Phil Hobbs]

On 12/22/2015 11:53 AM, Tim R wrote:
> On Tuesday, December 22, 2015 at 11:39:49 AM UTC-5, Phil Hobbs
> wrote:
>> On 12/22/2015 11:02 AM, c4urs11 wrote:
>>> On Tue, 22 Dec 2015 05:59:52 -0800, Tim R wrote:
>>>
>>>> However, my question is about how you would use a 1950s era
>>>> scope to determine a sine wave or the degree of harmonics
>>>> present.
>>>
>>> Scopes from that era easily reached several MHz of bandwidth.
>>> That should be considered adequate to inspect audio signals.
>>>
>>> Cheers!
>>>
>>
>> The eyeball is a really lousy detector of harmonics, though,
>> especially odd harmonics.
>>
>> Plus he had to use a 1950s-era microphone, so the scope bandwidth
>> is irrelevant.

>

> I've used an RTA, but those hadn't been invented yet. Before my
> time, but wasn't there something called octave filters?
>
> The experimenter wasn't real detailed but supposedly he could tell
> from looking at the scope that it was a pure sine without harmonics.

Well, he was wrong about that. Even 10% third harmonic isn't easy to
spot unless you have a comparison sine wave on the screen at the same
time. (I'm thinking about zero degrees relative phase, so the peaks are
symmetrical. It's a bit easier to see at other phases.)

> I was very skeptical that 1950s technology allowed that.

Unless he had a really expensive ribbon mic, his 1950s microphone had a
heavy diaphragm and rolled off really badly above about 5 kHz. (One of
the audio guys will correct this, but it's roughly right.) None of the
nice 40-kHz piezo film mics you can get nowadays. (I have a matched set
of Earthworks omni mics from about 15 years ago--their impulse response
is about 15 microseconds wide.)

> He is a believer that the material a trumpet is made from determines
> the sound, whereas many of us believe it is the shape of the air
> column.

It's both.

>
>
> I will quote the article: ****** At one time we ran an experiment in
> which we used steel, aluminum, various plastics, glass, silver,
> various combinations of brass and the last one we used was lead. To
> demonstrate results as quickly as possible, I will choose the two
> extremes. The steel bell, which we tempered so it was extremely
> hard, gave possibly one of the most interesting results. Many people
> test a bell by tapping it with their finger or knuckle and in tapping
> the steel bell, it would emit a very ringing sound, truly like a
> bell. However, when we played this instrument, the quality of sound
> was extremely dead. On searching for the reason for this, we looked
> at the oscilloscope when the performer played on the instrument and
> found the sine pattern very faint but the distortion pattern, coming
> from the vibration of the bell itself, going through at a very
> jagged and rapid rate, killing the brilliance of sound of the true
> tone.

Changing the material also moves all the mechanical resonances, which
will have a huge effect.

> At the other extreme was the lead bell. This bell, if rapped with
> your knuckle, emitted an extremely dead sound like rapping on a piece
> of wood. However the sound that emanated when it was blown was
> extremely brilliant, brilliant to the point of being mechanical. This
> showed up on the oscilloscope as a perfectly true sine pattern, there
> being no distortions in the harmonics either above or below, and, as
> a result, the sound was absolutely pure but not usable musically,
> except for a general effect such as a percussion instrument would
> give.


> The voice, you know, registering on an oscilloscope, gives harmonics
> both above and below the note. These distortions, if we may call them
> such, give warmth to the tone. We have to have that "distortion" in
> order to have the sound acceptable to our ears as a musical sound.
>

Cheers

Phil "Not an audio guy" Hobbs

[amdx]

To do that you need to know the shape of a sine wave... perfectly.
You could use a dual trace and compare a sine wave to your trumpet note.

Or use your computer sound card and see what you really have.

Free sound card spectrum analyzers.

> http://www.nch.com.au/wavepad/fft.html?gclid=CMuPysOD8MkCFdgHgQodztEKYA

> http://www.qsl.net/pa2ohh/04audio.htm

> http://www.qsl.net/dl4yhf/spectra1.html


Mikek

[Tim R]

On Tuesday, December 22, 2015 at 12:53:50 PM UTC-5, amdx wrote:
> To do that you need to know the shape of a sine wave... perfectly.
> You could use a dual trace and compare a sine wave to your trumpet note.
>
> Or use your computer sound card and see what you really have.

Yes, in 2015 I can do this, and have.

My suspicion was that it was not really possible in 1956 to have done what he claimed to have done. I figured in the time domain the most you would see is a tiny ripple on a scope trace, maybe not detectable. But I asked the question here because you all actually know how to use scopes (and some of you may be old enough to remember 1950s scopes).

[Tim R]

On Tuesday, December 22, 2015 at 12:04:12 PM UTC-5, Phil Hobbs wrote:
> It's both.

>
> >
> Changing the material also moves all the mechanical resonances, which
> will have a huge effect.
>

I agree the material will have a huge effect on the mechanical resonances. It is not so clear that the mechanical resonances have any appreciable effect on the contained wind column resonances. There is no obvious theory why they should, and a couple of centuries of experiments have really failed to show much in the way of effect, whether done with listening tests or lab measurements.

[Sjouke Burry]

Just use a signal generator on the second scope channel,
switch to x/y mode, and produce an ellipse/circle slowly
rotating.
Distortions will show up quite well.
Even in 1950.

[Tim R]

I wondered about that. There was a long ago physics lab where we made Lissajous figures, but so long ago I didn't remember details.

[Jeff Liebermann]

On Tue, 22 Dec 2015 10:48:39 -0800 (PST), Tim R <timot...@aol.com>
wrote:

>My suspicion was that it was not really possible in 1956 to have done what he claimed to have done. I figured in the time domain the most you would see is a tiny ripple on a scope trace, maybe not detectable. But I asked the question here because you all actually know how to use scopes (and some of you may be old enough to remember 1950s scopes).

Heathkit intoduced its first oscilloscope, the O-1, in 1947 (for $50).
<http://www.nostalgickitscentral.com/heath/products/test.html#o>
The "O" series went from O-1 to O-12 with the bandwidth going from
about 150Khz to 5 MHz. I couldn't find a time line, but here's an O-2
schematic dated Jan 1948.
<http://www.nostalgickitscentral.com/heath/schematics/heathkit_schema_o2.pdf>
Offhand, I would say that it would have been possible in 1956.

Back in the stone age of signal analysis, the usual method of looking
at harmonics was to notch out the fundamental, and look at what was
left. At audio, notch filters are fairly easy to build with bug
discrete parts. In effect, an early distortion analyzer. I don't
have a date, but looking at the schematic of the first Heathkit
distortion analyzer, the HD-1, methinks the choice of tubes puts it in
the same time frame as the O-1:
<http://www.nostalgickitscentral.com/heath/schematics/heathkit_schema_hd1.pdf>
So, it might also have been possible to inspect the horns harmonic
content, if the player could hold a steady note.



--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Jeff Liebermann]

On Tue, 22 Dec 2015 12:31:21 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

No brain today (especially while talking on the phone).
The dates are on the web page, right two columns:
<http://www.nostalgickitscentral.com/heath/products/heathkit_test.html>
The Heath O-1 was sold from 1947 to 1947. By 1956, there were
probably a dozen scopes produced by Heathkit. The HD-1 distortion
analyzer went from 1948 to probably 1948. My guess(tm) is that Howard
Anthony ran out of WWII surplus parts and was forced to design a
modern replacement.

[MJC]

In article <i1cj7bhpur6bafo0i...@4ax.com>,
je...@cruzio.com says...

> So, it might also have been possible to inspect the horns harmonic
> content, if the player could hold a steady note.

Which reminds me that in a holiday job between school and college I
spent some time chatting up the test engineers who were checking an
audio amplifier. They just used a sine wave signal and listened on
speakers. So I leant on the speaker and whistled a beating note. The
technician spent a minute or two hunting for the source of the beats
until I ran out of breath and got chased out of the test bay...

Mike.

[whit3rd]

On Tuesday, December 22, 2015 at 8:39:49 AM UTC-8, Phil Hobbs wrote:
> On 12/22/2015 11:02 AM, c4urs11 wrote:
> > On Tue, 22 Dec 2015 05:59:52 -0800, Tim R wrote:
> >
> >> However, my question is about how you would use a 1950s era scope
> >> to determine a sine wave or the degree of harmonics present.
> >
> > Scopes from that era easily reached several MHz of bandwidth.
> > That should be considered adequate to inspect audio signals.

> The eyeball is a really lousy detector of harmonics, though, especially
> odd harmonics.

Not always; I have no trouble looking at a filtered triangle-wave type "sine"
and seeing the distortion, which is presumably under 1%.
"Pure" to the ear doesn't require a spectrum analyzer with parts-per-million
resolution and logarithmic display. I think the researchers were applying
a loose definition.

> Plus he had to use a 1950s-era microphone, so the scope bandwidth is
> irrelevant.

Carbon microphone, maybe, but dynamic microphones were very well
developed by then. A lot of early recordings were transcribed onto DVD,
and the sound quality improved because the SINAD of microphone and tape were better
than the rest of the phonograph process.

[Phil Hobbs]

On 12/22/2015 05:07 PM, whit3rd wrote:
> On Tuesday, December 22, 2015 at 8:39:49 AM UTC-8, Phil Hobbs wrote:
>> On 12/22/2015 11:02 AM, c4urs11 wrote:
>>> On Tue, 22 Dec 2015 05:59:52 -0800, Tim R wrote:
>>>
>>>> However, my question is about how you would use a 1950s era scope
>>>> to determine a sine wave or the degree of harmonics present.
>>>
>>> Scopes from that era easily reached several MHz of bandwidth.
>>> That should be considered adequate to inspect audio signals.
>
>> The eyeball is a really lousy detector of harmonics, though, especially
>> odd harmonics.
>
> Not always; I have no trouble looking at a filtered triangle-wave type "sine"
> and seeing the distortion, which is presumably under 1%.

You're looking at the residual cusp, though, not the smooth details of
the peak, right?

> "Pure" to the ear doesn't require a spectrum analyzer with parts-per-million
> resolution and logarithmic display. I think the researchers were applying
> a loose definition.
>
>> Plus he had to use a 1950s-era microphone, so the scope bandwidth is
>> irrelevant.
>
> Carbon microphone, maybe, but dynamic microphones were very well
> developed by then.

Sure, but they have big heavy diaphragms and coils, so their high
frequency response stinks. (Velocity sensitivity helps, but low
resonant frequency wins.)

A lot of early recordings were transcribed onto DVD,
> and the sound quality improved because the SINAD of microphone and tape were better
> than the rest of the phonograph process.

I don't doubt that one bit. Record cutters especially.

[Bennett Price]

Could you give a citation, reference (or even a URL) to the article.
I'd love to read it.
Thanks

[Jeff Liebermann]

On Tue, 22 Dec 2015 21:26:20 -0000, MJC <gra...@mjcoon.plus.com>
wrote:

You're evil. I like that.

In roughly 1968, I worked in a shop that did warranty repairs on
various consumer audio equipment, mostly tape recorders. The owner
was rather cheap and decided we could do without much test equipment.
We had one ancient DuMont scope, which was only rarely used.
<http://www.radiomuseum.org/r/dumont_la_oscilloscope_304_a304.html>
When it came time to check for distortion or other audio anomalies,
instead of test equipment, we had Mario.

Mario had zero mechanical ability. Give him a soldering iron and he
was as likely to burn himself as solder the connection. If there was
a cable on the floor, he would find it and trip over it. If he tried
to fix anything, it was usually cosmetically ruined. Most of the
vehicles in the parking lot had dents from his futile attempts to park
his car. By all reason and logic, Mario was not suitable for working
in a repair shop.

However, Mario had amazing hearing. Not only could he detect and
identify many forms of audio distortion, but he could identify which
components were likely to be the cause. At one point, we hired a
clueless student, who knew little about electronics except how to
solder, to just replace the components that Mario identified. The
batting average was amazingly high. I even tried to trick Mario by
creating problems. He did quite well with up to four simultaneously
failed components. More was considered not worth repairing. When
Mario caught a cold or flu, we all took a short vacation, as nothing
was getting fixed using what little test equipment we had.

[Phil Allison]

Tim R wrote:
>
>
> There is an old paper where a musician claims to have used an oscilloscope to measure a particular trumpet tone and proved it was a pure sine wave. There is no date available but probably late 50s, the company was started in 1956. So we're talking whatever scope technology would have been available then.
>
> I've always been a bit skeptical about the claims because there are some other aspects that don't make sense to me.
>
> However, my question is about how you would use a 1950s era scope to determine a sine wave or the degree of harmonics present.
>
>

** The same way you might use a modern scope.

A sine wave has a distinct shape and the addition of harmonics visibly alters that shape. Instruments like the clarinet produce near square waves when playing most notes. Guitar strings vibrate with a series of harmonic frequencies, depending how the string is struck. You can clearly see them on a scope screen if you plug an electric model into the vertical input.

Check out U-Tube vids.

> Most musical tones have a series of harmonics above the
> fundamental that add the characteristic tone.
>

** Scopes show the time domain picture of a wave.



.... Phil

[isw]

In article <56799ed2$0$26104$e4fe...@textnews.kpn.nl>,

Hoe many trumpeters do you know who can hold a pitch that accurately
(essentially zero error for a slow rotation) for that long?

Isaac

[Sjouke Burry]

Long enough to see how distorted the circle/ellipse is.
You control the signal generator, to keep the
frequency almost tracking.
Your eyes and your brain can judge a picture very fast.

[isw]

In article <fZWdnbkiXZYUH-TL...@supernews.com>,

Condenser mics were not common at that time, but certainly were not
rare, either. The Altec 21B went to 15 kHz, which would handle the
overtones of any real-world musical instrument easily.

Isaac

[John Heath]

Interesting foot note. A condenser microphone has a small plastic disk inside that is always + on one side and - on the other. It is a charged condenser that can never be discharged no matter how you try to short it out. The molecules inside the plastic disk are frozen that way somewhat like a permanent magnet.

Anyways to the subject at hand. If a guitar string is plucked in the middle of the guitar it makes a sound. If the string is plucked close to the bridge it makes a different sound rich in higher harmonics. The difference between middle and bridge is the difference between sine wave and sine wave plus higher harmonics. In short your ear can detect a sine wave without the need of a oscilloscope. The same is true when repairing a graphic equalizer. The first time we bring out the guns with oscilloscopes , spectrum analyzers and sweep generators. By about the tenth time doing this you just use a Beatles song and let your ear tell you if the graphic EQ is okay or needs sliders cleaned or what not.

[jurb...@gmail.com]

>"Well, he was wrong about that. Even 10% third harmonic isn't easy >to
>spot unless you have a comparison sine wave on the screen at the same
>time. "

And that's if you know what you're looking for. Personally, I think I could detect lower, but I am not the norm. Second order harmonics should be easier to detect with the aid of the "invert" button.

I have come to the conclusion that an invert on at least one channel is essential.

Anyway, I think the trumpet might be near sine wave at its upper ranges. Just from my ears a can guarantee it is not at the lower ones. Listen to, shit, wait a minit...

https://www.youtube.com/watch?v=HX1t9yy-vmo

Most of the aggregation (is that the right word ?) of the sound is the attack and decay of course, but there is a wah wha part of it. Later, he gets up to the higher notes, and then some of those could be sine waves. That horn is a certain size and all that and the response does roll off at a certain frequency just like a speaker.

At that whole system's highest possible resonant frequencies, the output must approach a sine wave.

I would go get you Pink Floyd - Dogs Of War for the super high notes on the saxophone. Unfortunately I can't find the right version in good enough time, it is late. But I suspect alot of wind instruments approach a sine wave at the upper end of their range.

[Tim R]

On Tuesday, December 22, 2015 at 6:21:31 PM UTC-5, Bennett Price wrote:
>
> Could you give a citation, reference (or even a URL) to the article.
> I'd love to read it.
> Thanks

Sure. At the risk of veering off topic, so with apologies.

Background: For centuries musicians have ascribed tone properties to the materials instruments are made of, while physicists shake their heads because the math seems to say that given sufficient wall thickness the material should make no difference. Physicists who play an instrument are of course caught in the middle.

When the argument gets rehashed, which happens frequently, the skeptics point to the Smith review:
http://la.trompette.free.fr/Smith/IOA/material.htm
There are of course many more papers than that that didn't find a difference but that's the easiest to find and understand. It reviews 13 of the better studies. It isn't that easy to make two identical instruments of different materials, or in fact two identical ones of the same material.

There are only two "studies" that get quoted by the true believers: the Schilke study, quoted here:
http://www.dallasmusic.org/schilke/Brass%20Clinic.html
which is the one under discussion currently. You can see there is no date, no description, no publication, it's just a handout from a sales convention.
The other one is the famous Conn study which suffers from the same absence of the actual original report so it gets quoted by both sides.

[Bennett]

Warning Off topic:

Thanks for the references. (I found the 'effect of lacquer' portion of
Schilke's article really interesting and perhaps even convincing as my
girl friend is considering de-lacquering her french horn) I play
clarinet and the same sort of controversy exists for woodwinds -
grenadilla vs. rosewood vs. delrin vs. ebonite vs. rubber, etc. In
clarinets, it is clear that the performers are much more important than
the composition of the instrument on which they're playing. But it's
almost next to impossible to compare apples to apples since, as with
brass instruments, the clarinets made of different materials also have
different bore dimensions, undercutting, and other dimensional
variations. And of course even with 2 instruments made of identical
materials, one may cost $300, the other ten times as much.
And 2 'identical' instruments, same make/model/vintage, may have subtle
differences, particularly in intonation.

[Michael A. Terrell]

John Heath wrote:
>
> Interesting foot note. A condenser microphone has a small plastic disk inside that is always + on one side and - on the other. It is a charged condenser that can never be discharged no matter how you try to short it out. The molecules inside the plastic disk are frozen that way somewhat like a permanent magnet.

You are describing an Electret Microphone. It is a subset of
Condenser Microphones. The others require a very well filtered high
voltage source to keep the condenser charged.

[jurb...@gmail.com]

>"differences, particularly in intonation"

By intonation do you mean the same thing as when you set up the neck of a guitar ? On a guitar you basically set the twelfth fret to be exactly one octave up. I do not know about other instruments much. Fretless stringed instruments I guess you can set however you want, but that is not going to be true of brass, wood or wind.

Or are you talking about the harmonics ? The word intonation could be taken as that, and rightly by certain people who are talking about the tonal quality rather than the tone itself. Which is it ?

What's more, is there a way to set intonation, like on a guitar, on saxes, clarinets, and all that ?

I am a bit curious about all this.

[Bennett Price]

I'm using 'intonation' to mean proper well-tempered tuning, e.g., C mid-
staff should be precisely an octave (2x the frequency) of middle-C below
the staff. On clarinets each note should be in well-tempered tuning
with every other; that doesn't happen. As well, there's a 'register
key' when opened that is supposed to raise the pitch a perfect 12th -
this doesn't work out as it ideally should. A middle-C (right below the
staff) goes up to a top-line G when the register key is opened - it
should be a perfect 12th but it rarely is. Instrument designers do the
best can to make their instruments completely in tune with themselves
but it is impossible due to the '12th key'. All the holes that
determine pitch (along with the bore dimensions, barrel, bell,
mouthpiece, reed and players oral cavity) have an effect on the pitch.

I should add, as well, that the clarinet, within reason, can be tuned to
other instruments by pulling out the barrel and/or middle joint. This
is routinely necessary as the instrument warms up and thus goes up in pitch.

Intonation in the other sense you're using it, harmonics, are peculiar
to the clarinet, as they are primarily odd, not even harmonics of the
fundamental.

All of this oddness is due to the fact that the clarinet is basically
cylindrical (not conical like a sax or oboe) and closed at one end
(where the mouthpiece is) unlike a flute.

[jurb...@gmail.com]

I took your use of the word intonation in the wrong context because not alot of people know about the musical instrument aspect of it.

I have made myself and a few guitarists happy by setting the neck so they play nice and easy. Usually on electric guitars, very few acoustics are adjustable, at least that I have seen. Also, recently (to me that is like five years) I learned how to set up and tune a violin. Of course without frets you can make it how you want it. With frets it has to be right.

Hmm, OK trumpets and whatever need to be tuned, but what about a trombone ?

[Phil Allison]

Bennett Price wrote:
>
>
>
>
> Intonation in the other sense you're using it, harmonics, are peculiar
> to the clarinet, as they are primarily odd, not even harmonics of the
> fundamental.
>
> All of this oddness is due to the fact that the clarinet is basically
> cylindrical (not conical like a sax or oboe) and closed at one end
> (where the mouthpiece is) unlike a flute.

** Ah, this explains the clarinet producing acoustic square waves.

A combination of fundamental tone, third, fifth and seventh harmonics.



.... Phil

[Tim R]

On Friday, December 25, 2015 at 6:16:13 PM UTC-5, jurb...@gmail.com wrote:



> Hmm, OK trumpets and whatever need to be tuned, but what about a trombone ?

Like most brass instruments a trombone comes with a main tuning slide. It is a U shaped piece of tubing right on the top (behind your head when you're playing). You set that for the group you're playing with.

But you also make fine adjustments with the slide that moves. Trombone is "fretless" just like a violin. The slide has an approximately correct position but it always has to be slightly fine tuned for every note, because there are many notes in each position but all have tendencies to be sharp or flat, and notes sometimes have to be adjusted sharp or flat because of the musical context.

I've been playing in various groups for most of the past 50 years, and I've observed a recent tendency to standardize pitch much more. In the 60s a Stroboconn tuning machine cost $2600, which was more than a car back then. Now everybody has a $20 electronic tuner that is just as accurate. While not everybody uses them correctly, the overall effect is that groups have a central pitch much closer to 440 than in the old days.

[Ralph Mowery]

"Tim R" <timot...@aol.com> wrote in message
news:b2ec33a3-0d5a-459b...@googlegroups.com...

Around 1964 our Jr High had a band program and had one of the Stroboconn
machine. I thought it was called a Stroboscope, but hard to remember what
it was from over 40 years ago. Maybe the band director called it wrong
then.

I do remember the trombones being adjusted like you said. P:iece on the
back was moved in or out. I never did know how they could move the slide in
and out for the different notes and get them right. I think the band
directors favorite note was a B to set everyone to.

[John Heath]

One more step off subject. Apologies in advance. I remember being in a band in my 20s. Those were great years playing local bars. Unfortunately I did not have the magic so I stayed with electronics. What is that magic? I have played with some greats and it always surprises myself how they can hear a song one time and just run with it while I have to work for it. Ask Sammy Davis Jr what key to play in and he will say whiskey. What is that magic?

[Bennett Price]

The strobe tuner of yore is still available:
https://www.petersontuners.com/shop/Mechanical-Strobe-Tuners

[Tim R]

check this out, it explains the circuit (back on topic for the forum)

http://home.grandecom.net/~garybrookshire/files/conn%20st-1%20manual.pdf