online pitch source

[Alan Barnard]

That is cool stuff. Put it on stereo with one side at A440 the other at say
A440.11  ... wild.

If you want to practice hearing 7 bps per second, enter one side 7 Hz (not
cents) sharp or flat of the other.

Interesting!

By the way, on mono, sine wave, set at 440Hz, the tone measured 440.11Hz
according to my Tunelab Pocket, which is calibrated to the gummint's
standard. Not too shabby!

Alan Barnard
Salem, Missouri


> [Original Message]
> From: Geoff Sykes <thetuner at ivories52.com>
> To: Pianotech List <pianotech at ptg.org>
> Date: 05/15/2006 2:27:29 PM
> Subject: RE: online pitch source
>
> I just remembered this nifty little program I have on my computer that
might
> be useful here. It is a tiny little downloadable program called NCH Tone
> Generator. It has something like a 30 day free trial period, but it only
> costs about $20 US. 
>
> http://www.nch.com.au/tonegen/index.html
>
> -- Geoff Sykes
> -- Assoc. Los Angeles
>
>
> -----Original Message-----
> From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On
Behalf
> Of Philippe Errembault
> Sent: Monday, May 15, 2006 4:31 AM
> To: Cy Shuster; Pianotech List
> Subject: Re: online pitch source
>
>
> Hi all,
>
> With a computer, you have two possibilities, both can come from a file, so
> having the ressource on line will not help (except if you don't knowhow to
> download it on you computer). Only "usefull" online ressource I could
> imagine, would be a reference timebase like we use in the network time
> protocol. The problem with such a ressource, is that on the short term the
> delay introduced by the network will completely garbage it. This is only
> usefull to have a precise time of the day.
>
> Now, about the sound files themselves, In all cases, you will be depending
> on clock frequencies generated on you computer. Those clocks are generated
> by quartz which have a relatively good precision, but which will most
> probably be more precisely tuned for a time related clock than for a music
> related clock. now, I expect that electronic synthetisers will be
relatively
> precisely tuned, or you would have a problem playing with more than one. I
> don't know, it might be the case...). Instead of using your computer, you
> have another option which is playing this from an MP3 (or alike) walkman
(In
> this case, I the error will probaby be larger)
>
> you have two possibilities : Either you use recordings ("wave kind" files)
> or synthe "midi kind" files. The waves can be compressed (.mp3 files, .wma
> files, .ogg files, etc.) or not compressed (mostly .wav files). In both
> cases, waves are numeric samples supposed to be played at a certain speed
> (like on a CD).  their precision will depend on the precision of the clock
> inside your wave player. In the case of compressed files, you have another
> problem with the quality of the file itself. according to the compression
> rate, the compression will more or less reshape your wave, in a way which
is
> not related to your wave period. so the risk, is not only that you add
> harmonics to your wave, but that you add a slight modulation, which would
> add spurious frequencies around you center frequency. I have never tried
to
> measure this so I don't know in which measure it can cause a problem for
> tuning.
>
> You can record you own waves, but it would probably more precise to build
it
> by calculation (and optionnaly to chech it with you tuning fork). I built
my
> own set of wave files according to the inharmonicity I measured on my
piano.
> I put it on my MP3 player and tested my A440 against my fork, which shown
a
> 1/2 Hz beat, which make an error around 2 cents. By the way, I found quite
> difficult to tune from this source, but since I'm no experienced tuner,
this
> doesn't mean much.
>
> Another possibility, with a computer, is to use it's synthe, by piloting
it
> with a midi file wich is HUGELY ;-)  smaller than a wave. note that if
your
> computer has a software synthe, you will get the same quality than with
> waves (with still the advantage of the smaller file. In this case, it
might
> happen that you use another clock which could be more precise (this is
higly
> hypothetic).
>
> The best option, would probably be to make a program which would measure
the
> speed at which samples are eaten by the computers sound device, compare it
> with the system clock which is probably more precisely adjusted (a drift
of
> 5 sec/day is equivalent to a 0.1 cents error), and automagically
compensate
> the soundboard error by adjusting the waveform . Such a program probably
> needs to be written.
>
> Philippe Errembault
>
> ----- Original Message ----- 
> From: "Cy Shuster" <cy at shusterpiano.com>
> To: "Pianotech List" <pianotech at ptg.org>
> Sent: Monday, May 15, 2006 1:22 AM
> Subject: Re: online pitch source
>
>
> > Might not an .MP3 audio file of an A440 tone be independent of network
> speed
> > or computer hardware?
> >
> > --Cy--
> >
> >
> >
>