For closer listening comparison I assembled audio files of the printing
press and the interview noise into an audio editor so I can easily toggle
back and forth from one to the other. Again they sound nothing like one
another.
Whatever the noise, it is loud on the tape. It must have also been a fairly
quiet sound naturally but being VERY close to the microphone, it comes
across loud. If it were a loud noise coming from another room, there would
have been little direct sound to the microphone and much reflected sound,
making it a reverberant or "wet" sound. But on the tape we hear a "dry"
chattering sound with little room reverberation added. That is why the idea
of a noisy device in another room, or even close to the interviewee seems
incredible. If it were, it wouldnt sound so "dry". It would sound more like
the interviewee himself whose voice contains added room reflections from
walls, ceiling, floor etc.
A fan creating air disturbance between the interviewee and the microphone?
When two people are talking in a room and one is speaking much louder than
the other - or is much closer to us - the louder voice MASKS the quieter and
we struggle to hear the words of the quieter voice. Here on the tape, the
noise - whatever it is - simply masks the words of the interviewee. That is
normally a sufficient explanation.
Tim Gillett
Perth,
Western Australia
----- Original Message -----
From: "Paul T. Jackson" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, July 09, 2017 1:03 AM
Subject: Re: [ARSCLIST] Unexplained sound on oral history cassette
> Of course. No sound will be the same unless one goes back to the original
> source. No two printing presses will have the same sounds either. I was
> concentrating on the repetitiveness and rhythm of the sounds in the
> sample.
> On further thinking it could well be an oscillating fan as someone
> suggested, very near the speaker as the voice is distorted each time which
> could be the air from the fan breaking up the sound stream of the speaker.
>
> Paul T. Jackson
> Trescott Research
> Steilacoom, WA 98338
> [log in to unmask]
> trescottresearch.com
>
> On Jul 7, 2017 7:37 PM, "Tim Gillett" <[log in to unmask]> wrote:
>
>> Thanks for the audio example of the press Paul. The sound of the press is
>> very different from the sound on the recording in a number of ways.
>>
>> But also the voice recoding contains considerable room reverberation.
>> The creaking sound does not. How likely would it be for the microphone to
>> be placed right on top of such a printing press, with the interviewee on
>> the distant side of the room?
>>
>> Tim
>>
>>
>> ----- Original Message ----- From: "Paul Jackson" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Saturday, July 08, 2017 6:28 AM
>> Subject: Re: [ARSCLIST] Unexplained sound on oral history cassette
>>
>>
>> Everyone has made good argumentsthat the sound is from the tape
>>> processing noise. But having worked with printing machines I'm a bit
>>> more
>>> inclined to believe it's a printer in the background.
>>>
>>> Here is the actual sound of a Heidelberg Platen Printing Press; why
>>> I
>>> think it is this in the background, perhaps behind an open door in
>>> another
>>> room. http://www.workwithsounds.eu/sound/heidelberg-platen-press/
>>>
>>> --Paul Jackson
>>>
>>>
>>> On 7/7/2017 2:53 PM, Tim Gillett wrote:
>>>
>>>> I dont think the creak sound emanates from the room but from the
>>>> recorder. It carries very little room reverb so must be very close to
>>>> the
>>>> mic, whereas the speaker's voice carries lots of room reverb,
>>>> suggesting a
>>>> distant mic placement from him.
>>>>
>>>> The frequency of repetition of the "creak" seems roughly the same as a
>>>> complete rotation of the supply tape pack around the beginning of a
>>>> tape
>>>> side, so perhaps a cyclic binding of the supply tape pack at each
>>>> rotation.
>>>>
>>>> The creak sounds mechanical. It could be related to the primitive
>>>> tape auto stop in many cheap cassette recorders which consisted of a
>>>> small
>>>> "finger" pressing onto the tape through the cassette's small window
>>>> left of
>>>> centre. End of the tape greatly increased back tension pushing the
>>>> finger back, engaging a flywheel powered cog or cam which
>>>> mechanically
>>>> tripped the stop function. Often even at end of tape, the lever didnt
>>>> quite
>>>> fully engage into the cam or cog and instead "bounced" on it in a
>>>> chattering fashion, which may be the noise we are hearing: a false or
>>>> partial triggering due to the increased back tension. But the
>>>> frequency of
>>>> the creak seems too fast for a "one cam" type on the flywheel, The
>>>> frequency of creak impulses should be much slower, or exactly the same
>>>> speed as the capstan's rotation. But perhaps it wasnt a single cam but
>>>> a
>>>> toothed cog pressed onto the capstan shaft. I had a Sony TC
>>>>
>>>> The regularly varying whine seems to indicate constant "wow", which
>>>> seems to correlate with an unnatural rise and fall of the speaker's
>>>> voice.
>>>> Hard to say if the whine is from the machine or something in the room.
>>>> Around 0:40 the operator appears to move the microphone , whereby the
>>>> sound
>>>> of the creak disappears. Around the same time the faint whine seems
>>>> also to
>>>> decrease in level a little. So perhaps an external microphone was used
>>>> but
>>>> (at first) was placed right on the cassette recorder - a real "no, no".
>>>> The
>>>> loud creak sound we hear would have been much quieter for the operator
>>>> who
>>>> would have been much further from the source of the machine noise, but
>>>> at
>>>> least they heard it and appeared to have the presence of mind to move
>>>> the
>>>> mic from the recorder.
>>>>
>>>> At out State Library of Western Australia Oral History digitisation
>>>> programme we encountered many cassette recordings made with internal
>>>> mics
>>>> or sometime external mics possibly left sitting on top of the machine.
>>>> Many had so much background machine noise the voices were very hard to
>>>> listen to or bordered on the unintelligible. What an improvement these
>>>> days
>>>> with motorless flash memory recorders!
>>>>
>>>> Tim Gillett
>>>> Perth, Western Australia
>>>>
>>>>
>>>>
>>>> ----- Original Message ----- From: "John Chester" <[log in to unmask]>
>>>> To: <[log in to unmask]>
>>>> Sent: Saturday, July 08, 2017 3:20 AM
>>>> Subject: Re: [ARSCLIST] Unexplained sound on oral history cassette
>>>>
>>>>
>>>> The distinct midrange tone in this recording varies from about 870 to
>>>>> 950 Hz. Spectrogram shows it as a series of scallops. There's a wide
>>>>> curve as it drops to 870 Hz, then starts rising again. When it
>>>>> reaches 950
>>>>> Hz, the "creak" happens, and the tone frequency starts dropping.
>>>>>
>>>>> I think this was a cheap cassette machine, and the cassette was
>>>>> jamming. I assume that playback speed was constant when this transfer
>>>>> was
>>>>> done. If the speed was varying during recording, high tape speed
>>>>> during
>>>>> recording = lowest tone frequency on playback, and vice-versa. When
>>>>> the
>>>>> tone is around 870 Hz, recording speed was normal. As the tone rises
>>>>> in
>>>>> frequency, the tape was slowing down during recording. I think the
>>>>> "creak"
>>>>> is either mechanical noise from the cassette, picked up by a
>>>>> microphone
>>>>> built into the recorder, or electrical noise generated by the capstan
>>>>> motor
>>>>> governor when it freaks out because it can't rotate the capstan at the
>>>>> correct speed.
>>>>>
>>>>> Whatever the cause, it's clearly recorded on the tape. The spectrum
>>>>> of
>>>>> the "creak" extends up to about 10 kHz. The voice sounds have a
>>>>> similar
>>>>> upper limit. If this noise was generated during playback, it would
>>>>> probably extend all the way up to 20 kHz. But I can't imagine how it
>>>>> could
>>>>> have been generated during playback.
>>>>>
>>>>> -- John Chester
>>>>>
>>>>
>>>>
>>>> ---
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>>
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