Could the "hum" on the recordings not be connected with the line power, but
something mechanical or electrical generated by the recording machine
On Sat, Nov 1, 2014 at 10:03 AM, Tom Fine <[log in to unmask]>
> Indeed, but as I said, Steve Lasker tuned to musical pitch and it happened
> to work out that the hum also sat at 120-121hz. Furthermore, to pitch it
> down to where those YouTube clips are, I think you're down below 100hz with
> the hum. I would call that unlikely but not impossible in 1937 Texas.
> -- Tom Fine
> ----- Original Message ----- From: "Parker Dinkins" <
> [log in to unmask]>
> To: <[log in to unmask]>
> Sent: Saturday, November 01, 2014 8:08 AM
> Subject: [ARSCLIST] Robert Johnson Wrong Speed?
> Powerline frequencies in major cities in the US were not synchronized
>> until after World War II. At all. The citation for this statement can be
>> found in the archive. It came from a US military source.
>> A much more detailed analysis of the vagaries of powerline frequency
>> pre-1965 was made by Mr. Brock-Nannestad on Nov. 3, 2009, with the subject
>> heading "power line frequency".
>> Hum signatures are a valuable resource for speed correction when they
>> come from a synchronized source, such as the modern power grid.
>> Parker Dinkins
>> Date: Fri, 31 Oct 2014 06:23:03 -0400
>>> From: Tom Fine <[log in to unmask]>
>>> Subject: Re: Robert Johnson Wrong Speed?
>>> Hi Thomas:
>>> The 2011 reissue IS the correct speed, based on the 120hz hum from the
>>> original recording equipment.
>>> I was trying to stop this mythology, after talking with Seth. Let me say
>>> again -- the 2011 IS the
>>> correct speed, unless there was some freak power system present in Texas
>>> that operated at some
>>> frequency other than 120hz (just about zero chance of that). So, again,
>>> what you hear on that 2011
>>> edition IS the correct speed. All other discussion of "theories" of
>>> other speeds are not based on
>>> facts. To quote Seth Winner again, "the hum doesn't lie."
>>> -- Tom Fine