Re: Revised autobeam settings patch -- cleaned up debug comments (issue1667044)

[Carl Sorensen]

On 6/23/10 2:55 AM, "Trevor Daniels" <address@hidden> wrote:

>> On 6/16/10 3:18 AM, "Trevor Daniels" <address@hidden>
>> wrote:
>>> Carl.D.Sorensen wrote Tuesday, June 15, 2010 11:27 PM
 
> Well, I'm no expert either.  My snippet above is based
> on Ross, p 92, which says "Do not notate a 3/4 measure
> that looks like a measure in 6/8 time."

This statement is missing in my edition of Ross.

> Poor English,
> but he goes on to show the first two of the three
> examples marked incorrect above, and clearly labels them
> as incorrect.
> 
>> And I adjusted the the autobeaming code so it would work according
>> to your recommendations.
>> 
>> Today I've been studying books to see what the references say,
>> because the
>> new rule I added caused a regression in 4/4 time.
>> 
>> I want to get some clarification.  If I understand your rules
>> correctly, you
>> believe that
>> 
>> f4 r8 f8[ f f]
>> 
>> would be incorrect beaming, and that instead it should be beamed
>> 
>> f4 r8 f8 f8[ f]
> 
> Yes; Ross gives exactly these patterns later on p 92 and labels them
> incorrect and correct respectively.  That's where my snippet came
> from.
> 
>> Ross, however (1970, page 92) shows the first pattern as "Another
>> use of the
>> beam in 3/4 time", rather than as an incorrect use.
> 
> Hhm.  Maybe we are looking a different editions.  All I can
> see earlier on p 92 are examples that don't contain rests, and
> it is the presence of the rest that is important, since this
> causes three quavers to be beamed together, making it look like
> a 6/8 measure.

I think I need to get a later edition of Ross.  In my edition, there is no
label of Incorrect and Correct above this snippet, although there is above a
previous snippet.  And later in the chapter he shows side-by-side snippets
that are both correct.

> 
>> The algorithm I developed to resolve that problem led to the
>> following inT
>> 
>> r8 f8 f8[ f] f8[ f f f]
>> 
>> where we previously had
>> 
>> r8 f8[ f f] f8[ f f f]
>> 
>> Ross (1970, page 91) shows the following as an acceptable beaming
>> in 4/4
>> 
>> r8 f8[ f f] f4 f8[ f]
>> 
>> Which would imply the the previous beaming is correct.
> 
> Agreed, although I don't think the new beaming here is as bad
> as making a 3/4 measure look like one in 6/8.

I agree.  And it's quite easy to add manual beaming in this case.

> 
>> The bottom line is that the new beaming rules solve the first and
>> third
>> incorrect cases in your example above.  However, the price of
>> doing that is
>> they split a previously acceptable beam in 4/4 time.
>> 
>> Let me summarize:
>> 
>> OLD                       NEW
>> 3/4
>> f4 r8 f8[ f f]            f4 r8 f8 f8[ f]
>> f4. f8[ b8. a16]          f4. f8  b8.[ a16]
>> 
>> 4/4
>> r8 f8[ f f] f8[ f f f]   r8 f8 f8[ f] f8[ f f f]
>> 
>> So are these beaming rules correct, or at least better than the
>> old ones?
> 
> I think they are better than the old ones, but I'd prefer
> to hear opinions from some real musicians.
> 

I agree on both counts.

Thanks,

Carl