[CAUT] pre-stretching new string?

[Ron Nossaman]

David Love wrote:
> We're talking apples and oranges here.  Just do the math.  A string halved
> which is at a particular tension is different than a change in length of a
> string at a particular tension that results in a change in tension.  If you
> have a string at 100 mms and stretch the string to 105 mms the tension will
> change and with it the pitch.  That is a different thing than halving the
> string at a certain tension which results in a doubling of the frequency at
> which it vibrates.   
> 
> David Love
> davidlovepianos at comcast.net 
> www.davidlovepianos.com
> 
> -----Original Message-----
> From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of John
> Delacour
> Sent: Sunday, June 10, 2007 1:57 PM
> To: College and University Technicians
> Subject: Re: [CAUT] pre-stretching new string?
> 
> At 10:11 am -0700 10/6/07, David Love wrote:
> 
>> Sorry, but it's not quite a complete enough formula for purposes of 
>> this discussion.  When comparing two strings that produce the same 
>> pitch but with different tensions, either the original length will 
>> be different or the diameter will be different (or both), thus a 
>> similar change in length will yield a different change in tension 
>> and thus pitch.
> 
> If this were so, then the whole basis upon which musical instruments 
> are designed would crumble.  When you halve the length of a vibrating 
> string, no matter how much strain is on it etc., you double the 
> frequency, and if you stop two unison strings of identical length but 
> of different mass, and thus tension, at the same point, you will make 
> precisely the same change in their frequency and they will still 
> sound in unison.  If this were not so it would be impossible to play 
> a guitar in tune unless the tension of all six strings were identical.
> 
> According to Wolfenden, if the temperature changes, and one of the 
> strings is well below its yield point whereas the second is close the 
> yield point, then the strings will produce a beat because the less 
> strained string is more sensitive to the change in temperature.  This 
> is easy enough to verify by a simple experiment, which I shall do in 
> the next few weeks once the new workshop is up and running.
> 
> JD

Apples and aglets, more like. Not even in the same category.
Ron N