Consider also phase changes!<br><br><div class="gmail_quote">On 19 March 2011 08:50, bergpiano <span dir="ltr"><<a href="mailto:dan@bergpiano.com">dan@bergpiano.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
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<div><font face="Arial" size="2">Del,</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2">It could be the waves returning to the player from
the room. If the waves interact all kinds of things can happen. Each room will
have it's character as well. Once those waves hit the air who knows what is
happening. Refelective sound is very complex.</font></div>
<div><font face="Arial" size="2"></font> </div>
<div><font face="Arial" size="2"></font> </div>
<div>
<div><font face="Arial" size="2">Dan Berg</font></div>
<div><font color="#008000" face="Arial Black">Berg Piano Services</font></div>
<div><font face="Arial Black" size="2">407-884-1814</font></div>
<div><font color="#0066cc" face="Arial Black" size="2"><a href="http://bergpiano.com/" target="_blank">http://bergpiano.com</a></font></div>
<div><font face="Arial" size="2">Your Home For Piano Help</font></div></div>
<blockquote style="border-left: 2px solid rgb(0, 0, 0); padding-left: 5px; padding-right: 0px; margin-left: 5px; margin-right: 0px;" dir="ltr">
<div style="font: 10pt arial;">----- Original Message ----- </div>
<div style="font: 10pt arial; background: none repeat scroll 0% 0% rgb(228, 228, 228);"><b>From:</b>
<a title="del@fandrichpiano.com" href="mailto:del@fandrichpiano.com" target="_blank">Delwin D
Fandrich</a> </div>
<div style="font: 10pt arial;"><b>To:</b> <a title="pianotech@ptg.org" href="mailto:pianotech@ptg.org" target="_blank">pianotech@ptg.org</a> </div>
<div style="font: 10pt arial;"><b>Sent:</b> Friday, March 18, 2011 3:14
AM</div>
<div style="font: 10pt arial;"><b>Subject:</b> Re: [pianotech] What is
bloom,</div>
<div><br></div>
<div>
<p style="line-height: 15pt; margin-bottom: 9pt;" class="MsoNormal"><span>Yes, well, I continue to wonder
just what it is that we’re actually hearing. Below is an idealized
illustration of what is happening at, and following, hammer impact. (It’s a
little more idealized than I would like but I don’t have any of my own on this
computer. This one is borrowed from the Five Lectures website.)The hammer
strikes the strings at about 3 sec. There is a chaotic spike immediately
following (the period of chaos is typically a bit wider than shown here). The
sound immediately begins to decay at some fairly rapid rate but, for this
note, at around 5 sec. the rate of decay changes. </span></p>
<p style="text-align: center; margin-bottom: 12pt; margin-left: 0cm; margin-right: 0cm;" class="MsoNormal" align="center"><b><span><img alt="Description: Description: Fig 1. Typical decay of a piano tone as illustrated by the sound pressure level versus time (Eb3 = 311 Hz). The decay process is divided into two parts; an initial attack part with a fast decay (prompt sound) followed by a sustained part with slow decay (aftersound)." src="cid:B10E9FFF9C4C482C80686E78D8A24857@BergInternet" width="301" height="223"></span></b><b><span></span></b></p>
<p style="line-height: 15pt; margin-bottom: 9pt;" class="MsoNormal"><span>From what I’ve been able to
figure out, the knee (at around 5 or 6 sec.) is where the strings vibration
pattern changes from a predominately transverse motion (perpendicular to the
bridge) to a more random, or rotational pattern. The note is still dying out
but at a slower rate. It continues thus until the sound dies out or, as in
this illustration, the damper drops.</span></p>
<p style="line-height: 15pt; margin-bottom: 9pt;" class="MsoNormal"><span>In all the samples I’ve
recorded and studied over the years I’ve never seen the sound level increase
after hammer impact and that first chaotic wave pattern. They all end up
looking like some variation of this. More ragged and uneven sometimes but they
follow this generally pattern. </span></p>
<p style="line-height: 15pt; margin-bottom: 9pt;" class="MsoNormal"><span>It leaves me wondering if what
we think we hear as “bloom” isn’t at least partially—perhaps
predominately—psychoacoustic. Our ears—or our brain’s interpretation of what
our ears detect—quickly become accustomed to that rapid drop-off following the
chaotic hammer impact and, when the waveform gets to the knee and the decay
rate slows (sometimes dramatically) we interpret the change as
“bloom.”</span></p>
<p style="line-height: 15pt; margin-bottom: 9pt;" class="MsoNormal"><span> </span></p>
<p style="line-height: 15pt; margin-bottom: 9pt;" class="MsoNormal"><span>ddf</span><span style="font-family: 'Comic Sans MS'; color: navy; font-size: 11pt;"></span></p>
<p class="MsoNormal"><span style="font-family: 'Comic Sans MS'; color: rgb(99, 36, 35); font-size: 10pt;">Delwin D
Fandrich</span><span style="color: rgb(99, 36, 35); font-size: 10pt;"></span></p>
<p class="MsoNormal"><span style="font-family: 'Comic Sans MS'; color: rgb(99, 36, 35); font-size: 10pt;">Piano
Design & Fabrication</span><span style="color: rgb(99, 36, 35); font-size: 10pt;"></span></p>
<p class="MsoNormal"><span style="color: rgb(99, 36, 35); font-size: 10pt;">6939
Foothill Court SW, </span><span style="font-family: 'Comic Sans MS'; color: rgb(99, 36, 35); font-size: 10pt;">Olympia,
Washington 98512 USA</span></p>
<p class="MsoNormal"><span style="font-family: 'Comic Sans MS'; color: rgb(99, 36, 35); font-size: 10pt;">Phone
360.736.7563 — Cell 360.388.6525</span><span style="color: rgb(99, 36, 35); font-size: 10pt;"></span></p>
<p class="MsoNormal"><span style="font-family: 'Comic Sans MS'; color: rgb(99, 36, 35); font-size: 10pt;"><a href="mailto:del@fandrichpiano.com%20" target="_blank"><span style="color: blue;">del@fandrichpiano.com </span></a></span><span style="font-family: 'Comic Sans MS'; color: rgb(99, 36, 35); font-size: 10pt;">—
</span><span style="font-family: 'Comic Sans MS'; color: rgb(99, 36, 35); font-size: 10pt;"><a href="mailto:ddfandrich@gmail.com" target="_blank"><span style="color: blue;">ddfandrich@gmail.com</span></a></span><span style="color: navy; font-size: 11pt;"></span></p>
<p class="MsoNormal"><span style="font-family: 'Comic Sans MS'; color: navy; font-size: 11pt;"> </span></p>
<p style="margin-left: 36pt;" class="MsoNormal"><b><span style="font-size: 10pt;">From:</span></b><span style="font-size: 10pt;">
<a href="mailto:pianotech-bounces@ptg.org" target="_blank">pianotech-bounces@ptg.org</a> [mailto:<a href="mailto:pianotech-bounces@ptg.org" target="_blank">pianotech-bounces@ptg.org</a>] <b>On Behalf Of
</b>Dale Erwin<br><b>Sent:</b> Thursday, March 17, 2011 5:20 PM<br><b>To:</b>
<a href="mailto:pianotech@ptg.org" target="_blank">pianotech@ptg.org</a><br><b>Subject:</b> Re: [pianotech] What is
bloom,</span></p>
<p style="margin-left: 36pt;" class="MsoNormal"> </p>
<p style="margin-left: 36pt;" class="MsoNormal"><span style="font-family: 'Comic Sans MS'; color: black; font-size: 10pt;">Del<br>
Understood. I can't measure it empirically either. Fortunately we can hear
it.</span></p></div></blockquote></div>
</blockquote></div><br><br clear="all"><br>-- <br>Bruce Browning<br>The Piano Tuner<br>