On-hold Audio recording change on tempo

  • Thread starter DaveC426913
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In summary: This is a part of the clip just for reference:* I'm sorry it doesn't have the part where it changes tempo. I'll have to try again when the line is busier. ** I think it's pretty faint. I used OpenShot Studio to process it for uploading, which have some audio bugs in it.OpenShot Studio is notorious for having audio issues. I think it might be possible that the compression caused a change in tempo, but I couldn't find any other evidence of it.
  • #1
DaveC426913
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Can an audio clip change its tempo because of compression?
Once every couple of months I have to call the Ministry of Health about fifty times over the course of a day. Their hold music is an electronic ditty that loops every minute-ish, so I hear it a lot. It's very bad quality. I don't know if it's originally digital or if the original was recorded on tape and digitized. (It is conceivable that it is quite old since this is the Health Ministry which is usually decades behind in technology. I believe some of our headless utility programs run on MS-DOS.)

Anyway, in the recording, the tempo of the music wavers slightly. It speeds up a fraction for just a second. (It's always in the same place.) It does not have a corresponding rise in pitch. If you were tapping out the beat to this, you'd have to tap a litter faster for a second to stay on beat.

I'm wondering where this change in tempo might have crept in. One hypothesis is that it was originally on tape and the tape stretched, but that would cause a slowing of the tempo and a drop in pitch, so that can't be right.

Another hypothesis is the heavy digital compression. Can heavy digital compression cause a slight change in tempo?
This is a part of the clip just for reference:
* I'm sorry it doesn't have the part where it changes tempo. I'll have to try again when the line is busier.
** I think it's pretty faint. I used OpenShot Studio to process it for uploading, which have some audio bugs in it.
 
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  • #2
Some questions to ask:

- does it occur at a certain time of day? or only at a certain time in the music?

I'm thinking that certain times in the day the line frequency of AC systems rises for clock time corrections. Perhaps that affects the playback.

https://hackaday.com/2018/03/29/ask-hackaday-is-your-clock-tied-to-mains-frequency/

Another time of day condition is that people perceive music tempo as faster at night.

https://yonamariemusic.com/yona/blog/216/4-reasons-why-music-can-sound-faster-at-night

and then there's a deliberate change of tempo by the artis called tempo rubatot:

https://en.wikipedia.org/wiki/Tempo_rubato

Some radio stations or DJs may speed up songs slightly to give the impression of more energy in their broadcast or to match other tempos the DJ is trying to mix in.

https://arstechnica.com/civis/threads/am-i-crazy-or-do-some-stations-play-music-faster.587149/

https://pulsemusic.proboards.com/thread/58007/hit-radio-station-speed-songs

I recall hearing a song while waiting where a hiccup occurred at a specific point and suspected it was due to a tape loop splice either real or looping of a digital audio track.
 
  • #3
jedishrfu said:
- does it occur at a certain time of day? or only at a certain time in the music?
Nono. It's definitely part of the recording. I'm on hold for up to ten minutes at a time, so I hear the loop ten times in a row.

jedishrfu said:
and then there's a deliberate change of tempo by the artis called tempo rubatot:
Only if it were a fumble. It's only for a second or two.

jedishrfu said:
Some radio stations or DJs may speed up songs slightly to give the impression of more energy in their broadcast or to
No. Again, it's only for a few seconds. And, if you listen to the clip, you can tell the music is pretty repetitive, so a couple of beats being a little faster is a bit jarring.

jedishrfu said:
I recall hearing a song while waiting where a hiccup occurred at a specific point and suspected it was due to a tape loop splice either real or looping of a digital audio track.
Don't get me started on that.
I have a ringtone on my phone that's quite rhythmic. It's like 16 beats over 16 seconds, but the ringtone is, like, a 15 1/2 second loop. Grrr! They could have sped the ditty up by 5% or made the ringtone loop a half second longer.
 
  • #4
I looked for compression issues and couldnt find anything.

I did think that perhaps while doing the decompression there was a predictable garbage collection event.

Ive seen that with Java on some application runs.
 
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  • #5
There was a story about the early days of audio compression tech where a particular very popular song failed bigtime causing the developers to rethink the algorithm.

I think it was a Suzanne Vega archipela song that was the culprit.
 
  • #6
Ahh! I hear clip ends with that ubiquitous "Your call is important to us..." 'So we are putting you back on hold.' :frown:

(and here I thought it was just an American thing)
 
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  • #7
Many hold messages are downright sadistic. I got stuck on one once where every 20 seconds it would sound like someone was answering the phone and saying hello, only for the next words to be "...your call is very important to us...". And then it would dump you back into the same 20 second music loop. It seemed designed to maximize frustration and prevent you from doing anything productive while waiting! Horrible!


From an audio perspective, changing a song's tempo without changing its pitch is a complicated thing to do, and I doubt it could happen by accident. It could happen if the music was some kind of MIDI file, but I see no reason why hold music would function like that. An error while the hold music was being recorded is possible, but then why would the effect be intermittent. I suppose that sadism is as good an answer as any - they just want people to give up.
 
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  • #8
As an aside, I found the Suzanne Vega connection. It was her Tom's Diner song being used as the testcase for the MP3 algorithm.

https://www.npr.org/sections/therec.../the-mp3-a-history-of-innovation-and-betrayal

The key takeaway was that some sounds were removed if they were overlaid by other sounds capitalizing on limitations of human hearing.

and this Verge article shows you what you're missing when the Tom's Diner song is converted to MP3.

https://www.theverge.com/2015/2/19/8068923/mp3-compression-ghost-suzanne-vega-toms-diner
 
  • #9
jedishrfu said:
The key takeaway was that some sounds were removed
That's why it's called "lossy compression"!

Note there is an error in the linked article:
Maguire salvaged the sounds from "Tom's Diner" as it was shrunk from an uncompressed .wav file to a 320kbps MP3.
... if you read the original article https://www.theghostinthemp3.com/theghostinthemp3.html you will see that the source used was a 128kbps MP3.
 

Related to On-hold Audio recording change on tempo

1. How does changing the tempo of an on-hold audio recording impact the overall caller experience?

Changing the tempo of an on-hold audio recording can significantly impact the overall caller experience. A faster tempo can create a sense of urgency or excitement, while a slower tempo can convey relaxation or calmness. It is important to consider the tone and message of the on-hold audio when making tempo changes to ensure it aligns with the desired caller experience.

2. What tools or software can be used to change the tempo of an on-hold audio recording?

There are various tools and software available that can be used to change the tempo of an on-hold audio recording. Some popular options include audio editing software like Audacity, Adobe Audition, or GarageBand. These tools allow you to adjust the tempo of the audio recording while maintaining its quality and clarity.

3. Is it necessary to obtain permission to change the tempo of a licensed on-hold audio recording?

It is important to review the terms of the licensing agreement for the on-hold audio recording to determine if permission is required to change the tempo. Some licensing agreements may restrict alterations to the original recording, including changes to the tempo. It is advisable to seek permission from the copyright holder or licensing agency before making any modifications to the audio recording.

4. How can changing the tempo of an on-hold audio recording impact branding and messaging?

Changing the tempo of an on-hold audio recording can have a significant impact on branding and messaging. The tempo of the music or voiceover can influence how the brand is perceived by callers. A faster tempo may convey a sense of energy and innovation, while a slower tempo can communicate professionalism and reliability. It is important to align the tempo with the brand's messaging and values to ensure consistency and effectiveness.

5. Are there any best practices to follow when changing the tempo of an on-hold audio recording?

When changing the tempo of an on-hold audio recording, it is important to consider the overall tone and message of the recording. It is recommended to test different tempos to determine which one best aligns with the desired caller experience and brand image. Additionally, it is advisable to listen to the modified recording multiple times to ensure that the tempo change does not negatively impact the clarity or effectiveness of the message.

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