Speed of speech

It is most certainly digitally doable to make anyone speak faster if its
recorded. Its done by missing out some samples and shortening gaps between
words. Blind people have their speech cranked up quite often so the average
person could never under stand it. In my view doing that to a narrator of
some audio book is surely removing the natural sound, but each to their own.
I remember the first place I encountered this was in Tandy many years ago,
they had a tape recorder that could change the speech speed without changing
the voice pitch. I'm not sure how they did this back then, but I'd imaging
it used some kind of digital processing as you speeded the tapes up.
Brian
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Post by Pamela
Is it my imagination or do the presenters on Talk Radio/Talk TV (and
sometimes GB News) sometimes speak much faster than normal?
It's almost as if the programme is pre-recorded and played back at a
faster speed. Or perhaps the studio tells the presents to talk at top
speed.
Just wondering.

2023-02-03 14:46:48 UTC

Post by Brian Gaff
It is most certainly digitally doable to make anyone speak faster if its
recorded. Its done by missing out some samples and shortening gaps between
words. Blind people have their speech cranked up quite often so the average
person could never under stand it. In my view doing that to a narrator of
some audio book is surely removing the natural sound, but each to their own.
I remember the first place I encountered this was in Tandy many years ago,
they had a tape recorder that could change the speech speed without changing
the voice pitch. I'm not sure how they did this back then, but I'd imaging
it used some kind of digital processing as you speeded the tapes up.

I would have thought that the only way you could correct for higher
pitch with speeded up audio, before the days of digital processing,
would be to pitch-shift by modulating with a low frequency - which would
be tolerable for speech but would make music sound obnoxious because the
harmonic relationships would be destroyed.

I'm amazed as how good digital processing is in players such as VLC. I
tend to watch recorded programmes at about 1.3 to 1.5x normal, and music
as well as speech sounds fine. Only when you get up to about 1.7 to 2x
does it start to sound rather nasty.

Pamela

2023-02-15 14:12:41 UTC

Post by NY

Post by Brian Gaff
It is most certainly digitally doable to make anyone speak faster
if its recorded. Its done by missing out some samples and shortening
gaps between words. Blind people have their speech cranked up quite
often so the average person could never under stand it. In my view
doing that to a narrator of some audio book is surely removing the
natural sound, but each to their own.
I remember the first place I encountered this was in Tandy many years ago,
they had a tape recorder that could change the speech speed without
changing the voice pitch. I'm not sure how they did this back then,
but I'd imaging it used some kind of digital processing as you
speeded the tapes up.

I would have thought that the only way you could correct for higher
pitch with speeded up audio, before the days of digital processing,
would be to pitch-shift by modulating with a low frequency - which
would be tolerable for speech but would make music sound obnoxious
because the harmonic relationships would be destroyed.
I'm amazed as how good digital processing is in players such as VLC.
I tend to watch recorded programmes at about 1.3 to 1.5x normal, and
music as well as speech sounds fine. Only when you get up to about
1.7 to 2x does it start to sound rather nasty.

Your 1.3 to 1.5x normal is much faster than I find comfortable. 1.25x is
my limit but I prefer 1.1x although it's hardly enough to make any saving
of elapsed time.

Conversely ... I find slowing down a podcast (or whatever) is okay down to
about 0.8 to 0.9x but no slower.

Perhaps there's considerable variation between listeners.

Liz Tuddenham

2023-02-03 22:44:25 UTC

Brian Gaff <***@gmail.com> wrote:

[...].

Post by Brian Gaff
I remember the first place I encountered this was in Tandy many years ago,
they had a tape recorder that could change the speech speed without changing
the voice pitch. I'm not sure how they did this back then, but I'd imaging
it used some kind of digital processing as you speeded the tapes up.

It goes back a lot further than that: During WWII the Germans had a
magnetophone that could speed up and slow down sound without changing
the pitch, it was used for 'secrecy' when sending messages over a
limited bandwidth radio link.

It worked by having four heads on a rotating drum which ran either in
the same direction as the tape or in the opposite direction, depending
on whether you wanted to speed up or slow down the sound. The heads
were commutated as the drum went round.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

Pamela

2023-02-15 14:14:30 UTC

Post by Liz Tuddenham

Post by Liz Tuddenham
[...].
I remember the first place I encountered this was in Tandy many years ago,
they had a tape recorder that could change the speech speed without
changing the voice pitch. I'm not sure how they did this back then,
but I'd imaging it used some kind of digital processing as you
speeded the tapes up.

It goes back a lot further than that: During WWII the Germans had a
magnetophone that could speed up and slow down sound without changing
the pitch, it was used for 'secrecy' when sending messages over a
limited bandwidth radio link.
It worked by having four heads on a rotating drum which ran either in
the same direction as the tape or in the opposite direction,
depending on whether you wanted to speed up or slow down the sound.
The heads were commutated as the drum went round.

That sounds rather clever for the (historical) time.

Angus Robertson - Magenta Systems Ltd

2023-02-15 17:19:00 UTC

Post by Liz Tuddenham
It worked by having four heads on a rotating drum which ran

either in the same direction as the tape or in the opposite

Post by Liz Tuddenham
direction, depending on whether you wanted to speed up or slow
down the sound. The heads were commutated as the drum went
round.

That sounds rather clever for the (historical) time.

Even 50 years ago the essentially same technique was used to delay radio
phone-ins by a few seconds, two tape recorders in a rack with the tape looped
between them.

Electronic delays were probably not until the late seventies when analogue to
digital conversion and memory became economic.

Angus

Max Demian

2023-02-16 11:52:49 UTC

Post by Angus Robertson - Magenta Systems Ltd

Post by Liz Tuddenham
It worked by having four heads on a rotating drum which ran

either in the same direction as the tape or in the opposite

Post by Liz Tuddenham
direction, depending on whether you wanted to speed up or slow
down the sound. The heads were commutated as the drum went
round.

That sounds rather clever for the (historical) time.

Even 50 years ago the essentially same technique was used to delay radio
phone-ins by a few seconds, two tape recorders in a rack with the tape looped
between them.

That's different, as the whole programme is delayed by a fixed amount.
Not the same as speeding up speech without affecting the pitch.

--
Max Demian

Mark Carver

2023-02-16 12:23:34 UTC

Post by Angus Robertson - Magenta Systems Ltd

Post by Liz Tuddenham
It worked by having four heads on a rotating drum which ran

either in the same direction as the tape or in the opposite

Post by Liz Tuddenham
direction, depending on whether you wanted to speed up or slow
down the sound. The heads were commutated as the drum went
round.

That sounds rather clever for the (historical) time.

Even 50 years ago the essentially same technique was used to delay radio
phone-ins by a few seconds, two tape recorders in a rack with the tape looped
between them.

That's different, as the whole programme is delayed by a fixed amount.
Not the same as speeding up speech without affecting the pitch.

The digital profanity delay systems actually do that (or rather slow
down without affecting the pitch) to get into a 10 second linear delay.

'Back in the day' radio stations had to play a 10 second jingle, to fill
the gap between live and delayed output.

Max Demian

2023-02-16 16:36:53 UTC

Post by Angus Robertson - Magenta Systems Ltd
Even 50 years ago the essentially same technique was used to delay radio
phone-ins by a few seconds, two tape recorders in a rack with the tape looped
between them.

That's different, as the whole programme is delayed by a fixed amount.
Not the same as speeding up speech without affecting the pitch.

The digital profanity delay systems actually do that (or rather slow
down without affecting the pitch) to get into a 10 second linear delay.
'Back in the day' radio stations had to play a 10 second jingle, to fill
the gap between live and delayed output.

If the whole programme is delayed, what gap is there?

--
Max Demian

Mark Carver

2023-02-16 19:35:14 UTC

That's different, as the whole programme is delayed by a fixed
amount. Not the same as speeding up speech without affecting the pitch.

The digital profanity delay systems actually do that (or rather slow
down without affecting the pitch) to get into a 10 second linear delay.
'Back in the day' radio stations had to play a 10 second jingle, to
fill the gap between live and delayed output.

If the whole programme is delayed, what gap is there?

At the start of the programme of course. If the preceding programme is
live, you have to fill the gap before jumping to the delayed content.

Mark Carver

2023-02-16 19:37:19 UTC