[pianotech] What is bloom,

[David Love]

The problem I have with the reliability of the pluck test (sometimes it works and sometimes it doesn’t for me) is that soundboard health also has something to do with the *relationship* between the initial input of energy and the sustain phase that follows.  When you pluck the string you bypass that initial force of the hammer string contact and jump right to the sustain phase.  It can be misleading.  It’s not always that weak boards don’t sustain, sometimes they do sustain but just at a lower level.  It’s the relationship between the attack phase and the sustain phase that is the most telling.  At least that’s what I find.  

 

 

David Love

www.davidlovepianos.com

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of David Andersen
Sent: Friday, March 18, 2011 7:08 PM
To: pianotech at ptg.org
Cc: pianotech at ptg.org
Subject: Re: [pianotech] What is bloom,

 

OMG---finally some real-world data.

I can't believe that it's just Erwin and I who pluck strings, in the method described below, to assess soundboard health. All this speculative

sorta scientific wondering is missing the point. Good soundboards produce a bloom or a swell, a strengthening pulse, an added sustain, when the string is plucked, usually within 2 seconds of the pluck. whatever it technically is, it happens on high-functioning boards and is choked off, does not occur, in low-functioning boards. An extremely useful diagnostic phenomenon. Does that make sense?

DA


Sent from my iPhone


On Mar 18, 2011, at 5:52 PM, Dale Erwin <erwinspiano at aol.com> wrote:

Ron
  How about sound pressure, partial balance and clarity.  The short subjective version is that when I puck a string to test sustain I alwasy try  to pluck lightly with the same amount of force. If I pluck lightly and it just seems to be like a horse that wants to run free and easy...I like it...a lot. If I pluck a string lightly and there seems to be a resistance to vibrating freely...then that dog just won't hunt.
 Does that clear it all up?

 

 

Dale S. Erwin
www.Erwinspiano.com
Custom restoration
Ronsen Piano hammers
Join the Weickert felt Revolution
209-577-8397
209-985-0990



 

 

-----Original Message-----
From: Ron Nossaman <rnossaman at cox.net>
To: pianotech at ptg.org
Sent: Fri, Mar 18, 2011 5:39 pm
Subject: Re: [pianotech] What is bloom,

On 3/18/2011 3:23 PM, David M. Porritt wrote: 
> I am very aware of how our expectations affect what we see, hear, 
> believe etc. Could “bloom” be a result of different expectations? If we 
> are expecting decay like this: 
 
-Simulate steep decline graphic- 
 
> since that is what we get on most pianos, but if we get decay like this: 
 
-Simulate shallow decline graphic- 
 
> Our brain could interpret it as bloom since it is more than we expected. 
 
I agree, from my questionable experience. Reshaping the tonal envelope to produce a less dramatic impact spike, and a shallower transition into dwell, tapering gradually into decay gives the subjective impression of more sound (average) for longer. I've always much disliked the term "bloom" for this effect, since it doesn't, so "bloom" isn't really descriptive and I consider it misleading. It just dies more gradually, gracefully, and less traumatically, like UL approved electrical products. 
 
And it's still nowhere near the phenomenon JD brought up. 
Ron N 

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