Fred:
It's easier than you say if you use TuneLab. I set mine for 3:1 12ths
all the way through. The only difference for me is I turn the ETD off
when tuning the wrapped strings and do them aurally. Wrapped strings
are a little less predictable and I favor smooth octaves in the bass to
anything else. Besides that turning the ETD off for the wrapped strings
saves battery life!!
I've done 3:1 12ths for years. It makes checking easy too. Since I
start at F3 and tune upwards, as soon as I get to C5 I can play the 12th
below and if the display stops, I have my perfect 12th. That's just one
of the things I like about TuneLab, you set your stretch in real numbers
like 3:1, 4:2, 8:1 etc. Those mean more to me than a #6 stretch.
dave
David M. Porritt, RPT
dporritt at smu.edu
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Fred Sturm
Sent: Wednesday, October 01, 2008 4:00 PM
To: College and University Technicians
Subject: Re: [CAUT] Tuning a Steinway D and a Bosendorfer Imperial
together
Hi Kent,
Thanks for sharing this. Very interesting. I hadn't heard
about this program, or only very vaguely.
I don't think of a pure 12th as particularly wide as a basis
for tuning. Take a 3:2 5th above a 2:1 octave. Tuning conservatively,
the 3:2 5th will be about 2 cents narrow and the 2:1 octave will be
about 2 cents wide. Result: pure 3:1 12th. Someone looking to increase
stretch might shade the 3:2 5th a bit wider, say 1 cent narrow, and
shade the 2:1 octave wider as well, say 3 cents wide (meaning the
10th/17th test would have the 17th beating just less than 1 bps in mid
range). Not at all unusual, and the 12th will now be wide by 2 cents.
With "pure 5ths" as Jim Coleman wrote about a few years back, the 12th
will be wider than that. I would say that a tuning based on pure 3:1
12ths in the mid range would be fairly standard sounding, close to the
original FAC or an RCT 5 or 6.
If the 3:1 12ths are used consistently throughout the piano,
top to bottom, I would expect the result to be rather more narrow than
most of us tune, particularly in the bass. Your samples didn't sound
that way in the bass, though I thought the high treble sounded a bit
flatter than what I would want personally. I suspect the VTD does a 6:1
19th for the bottom couple octaves or so, based on what I heard.
Stopper sounds like he wants to be considered a mysterious
magician. Fine, let him. I got to wondering how one might do a 3:1
tuning "on the fly," and came up with a very simple way. Whether it is
the same as what he does, I have no way of knowing, but I know with
certainty that it would work just fine, and would be easy to set up (for
someone who knows how). This is not the easiest stuff to write about
clearly, so I'll just do my best and hope it is intelligible.
Start with a spreadsheet of 88 cells (like RCT does, and SAT
as well, in the background), one cell for each note. They are set up to
have 3rd partial values, except for the top 19 notes, which have 1st
partials. They are blank except for D3, which reads zero cents at A4
(the 3rd partial of D3). There are formulae in the background, but only
the one actual entered value.
The software is set up so that the ETD first reads the 1st
and 3rd partials of the note played, and compares the two, similar to
what we do to set up an FAC tuning on a SAT. 1st partial value is
subtracted from 3rd partial value to come up with a difference value.
The first note should be between D3 and A4 (it could be
farther afield, but that would involve extrapolation, and would yield a
less precise A4). For simplicity's sake, let's say we start at D3. The
ETD reads the 1st and 3rd partials of D3, calculates the difference in
value, and enters that difference as a negative value in the cell for G2
(a 12th below D3, whose value will correspond to the 1st partial of D3.
D3's 3rd partial will, by default, be A4 at zero). It then calculates a
curve between that number and zero, logarithmically even over 19 steps,
and fills in those values in the cells between G2 and D3. We now have a
total of 20 cells filled in with actual tuning values. In each case the
value is both the 3rd partial of the note to be tuned and the 1st
partial of the note a 12th above. This takes less than a second to occur
(miracle of modern processor speed), and we proceed to tune the 3rd
partial of D3 to A4 at 0 cents.
Tuning upward, play D#3. The difference between 1st and 3rd
partials is calculated, added to the value in cell G#1 (which
corresponds to the 1st partial of D#3), the result entered into the cell
for D#3, and we tune to that value. And so forth up to F6. Above F6, 1st
partial values are entered into each cell from the cell 20 notes below
(ie, the 1st partial will correspond exactly to the 3rd partial of the
note a 12th below. F#6 will correspond to B4, G6 to C5, and so forth up
to C8).
Tuning downward from D3, we already have values entered for
19 notes, so the ETD will be "calculating ahead" for the note a 12th
below. Starting with C#3, 1st and 3rd partials are read and compared.
The difference is subtracted from the value in the cell for C#3 and
entered into the cell for F#1. And so on until A0 has been filled, at
which point no more calculation is necessary. If, as would be advisable
IMO, we instead want 6:1 19ths in the bass, the task of filling in cells
is that much simpler. At whatever point you want that to happen, you
simply duplicate the pitch and number value of the note an octave higher
(eg, 3rd partial of C3 becomes 6th partial of C2).
I'm afraid statements like "Stopper claims to have a new way
for a VTD to deal with inharmonicity that is automatic. He says the VTD
display readings are based neither on single-partials nor
multi-partials, but rather are based upon a new approach" make me very,
very skeptical and wary. Personally, I don't believe in magic. ETDs are
based largely on quite simple principles and straightforward math, and
they work very well to produce acceptable tunings. I guess I would be
willing to say that the system I described above is a way to deal with
inharmonicity that is automatic. I'd be very surprised if his system is
much different. "VTD display readings are based neither on
single-partials nor multi-partials, but rather are based upon a new
approach" is pure gibberish to me. If it doesn't compare a measured
pitch to a standard in the background (or two or more measured pitches
to two or more standards in the background in the case of
multi-partials), I, for one, can't imagine what else it would be doing
that would be useful in tuning. Measuring and comparing, that's the name
of the game.
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu
On Sep 29, 2008, at 12:18 PM, Kent Swafford wrote:
These tunings were done with Bernhard Stopper's PureTuner VTD; it runs
on PocketPC.
You need to know just a bit about the software before you can understand
why the good results are so interesting. Stopper's tunings are based
theoretically on a pure twelfth divided into 19 equal half-steps. This
VTD takes no measurements from the piano being tuned in order to
calculate a tuning; one just boots up the program, determines a pitch
level for the tuning, and starts tuning.
Stopper claims to have a new way for a VTD to deal with inharmonicity
that is automatic. He says the VTD display readings are based neither on
single-partials nor multi-partials, but rather are based upon a new
approach.
Stopper claims that the results are consistent and superior. He claims
that that although the tunings are rather wide, there is an overall,
synchronous effect that gives a clean, beatless effect to chords. He
claims the software will deliver a best fit tuning for any level of
inharmonicity.
I have been using the software since June and I am finding that the
claims all appear to be true. I offer the recordings of Steinway D and a
Bosendorfer Imperial tuned together with Stopper's software as evidence.
I admit to some discomfort because Stopper has stated his intention to
withhold most explanations of how this all works.
The bottom line, though, is that the tunings sound good. Good enough for
my workplace which is a demanding university environment.
Kent
On Sat, Sep 27, 2008 at 7:37 PM, Mark Schecter <mark at schecterpiano.com>
wrote:
Hi, Kent.
They do sound well-matched, especially when you play the chromatic
scale; apart from that, it's hard to judge.
...
Thanks.
-Mark Schecter
PS OK, I'll bite. How did you go about it? Thanks!
Kent Swafford wrote:
I wanted to see if I could improve my ability to tune a Steinway D and a
Bosendorfer Imperial together. The Steinway has relatively high
inharmonicity and the Bosendorfer has very, very low inharmonicity. Some
of you will be familiar with the problem.
I have uploaded an audio file to:
http://www.kentswafford.com/mp3/d_dorf.mp3
The recording attempts to show that each piano is well-tuned with itself
and that the pianos also are tuned together. The Steinway plays first
and should be on the right. The pianos are side by side. There are a
number of bad unisons in the high treble, especially on the Bosendorfer.
You are welcome to come try to tune them yourself.
In the recording you hear:
Steinway arpeggios
Bosendorfer arpeggios
Bosendorfer chord of nature progression
Steinway chord of nature progression
Chromatic scale played both on both pianos together
I think the results are good. How I did this may surprise a few...
Later.
Kent Swafford
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