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Compression in audio recording - My thoughts

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Hari Iyer

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I am starting this post by saying that i dont like compressed sound. By compression, i did not mean file compression that we achieve by compressing a CD format to an mp3 format. What i meant by compression is in context to how audio is recorded in a media.

By definition compression tend to make soft sound loud and loud sound soft. This is useful to get all the sound a similar level during recording. But it looses in its sense the realism of what is been played / recorded. Some amount of compression is nice , good. But over compression is very bad.

Whenever i listen to the bollywood recordings of the 50s, 60s,70s and 80s i can find that the recording sound very real as there was "No" compression of audio signals those days and everything was recorded live as-is. So the instrument size and scale were easy to recognize with them. For instance violin sounded like violin in sound, size and scale and so did a base guitar or a saxaphone. These recordings can be seen from those of Naushad, Bappi Lahari or RD Burman types of music.

Coming to the compressed era or what i call ARRehman type of music, there is a case of lots of over compression. Everything sound too flat and detailed that you loose sense of the instrument size. Though it would be pleasing to listen them in literal sense but there is no sense of realism in the music as everything sounds same level. Agreed the instrument sizing is not a big deal for a casual listner or a background listner but for critical listner they do matter. For those who listen to music when parallel preparing an office presentation on their laptop on a Sunday evening for an early Monday morning meeting they wont even care for the compressed sound where more than 95% of the music listener currently are. So the industry cater to those ccustomers and dont even care of the rest of 5% of the listeners. To top it these over compressed recorded audio are boosted in level double or tiple time to win on the loudness war (most punjabi type rap songs of the current era)

I have also observed that some audio gear tend to compress the sound. It can be amplifier, source or even speakers. They tend to sound very flat to any type of music and there can be many reasons for that which is out of scope of this discussion.

I have listened to the AV Receiver designed by hfv FM Ravindra Desai who i believe use some kind of compression in his design by choice to make it flat sounding to all level of music. (though i am not sure).

Disclaimer: The above is entirely my own opinion and others may choose to differ.
 
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raghupb

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@Hari Iyer
You are referring to Dynamic Range Compression (DRC)
This approach in the recording industry started in the late 80s - early 90s when listening to music went aggressively personal.
Walkman/Discmans ruled roost in the last 2 decades of 20th century.
This was an effort to get more and more folks to buy recordings (a sensible business decision, but bad for audio quality).
IPoD and personal music players along with the proliferation of headphones (particularly IEMs) drove this trend to ... well, death.

Now there is an effort on various fronts, like resurgence of vinyl, MQA trend, etc to revive the "older charm" of listening to music the way it was originally recorded.
One of the people who should be given special mention (at least for 60s/70s prog-rock revival) is Steven Wilson.
A very talented guy, musician, songwriter and studio engineer; erstwhile Porcupine Tree band member.
Hope this trend gains traction, now that room based listening equipment is diverse and affordable and available worldwide.

Hope someone in the Indian recording industry takes cognisance of this and works constructively towards re-mastering originals for mass consumption.

Cheers,
Raghu
 

ajuvignesh

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I completely agree with this. There are songs that's are completely unlistenable. All thanks to loudness war. I often wonder how these music directors let it go that way. :(

@Hari Iyer
You are referring to Dynamic Range Compression (DRC)
This approach in the recording industry started in the late 80s - early 90s when listening to music went aggressively personal.
Walkman/Discmans ruled roost in the last 2 decades of 20th century.
This was an effort to get more and more folks to buy recordings (a sensible business decision, but bad for audio quality).
IPoD and personal music players along with the proliferation of headphones (particularly IEMs) drove this trend to ... well, death.

Now there is an effort on various fronts, like resurgence of vinyl, MQA trend, etc to revive the "older charm" of listening to music the way it was originally recorded.
One of the people who should be given special mention (at least for 60s/70s prog-rock revival) is Steven Wilson.
A very talented guy, musician, songwriter and studio engineer; erstwhile Porcupine Tree band member.
Hope this trend gains traction, now that room based listening equipment is diverse and affordable and available worldwide.

Hope someone in the Indian recording industry takes cognisance of this and works constructively towards re-mastering originals for mass consumption.

Cheers,
Raghu
He's referring to the over compression applied right from recording individual tracks to mastering stage.
 

Haribabu

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I too don't like word compression, the compression process started since digital era came into force. If you like music of post 90s there is no issue of compression (digitally), but early 90s music never play great if compressed.
People who don't like compression and serious old music enthusiast have already moved back to Analog audio.
that's the reason why Analog audio getting slowly on track.
 

plasmoid

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This is one of the biggest scams in the music industry that came about in the early 90's so they could resell entire artist/band discographies. I still remember all the hype stickers on CDs that said DIGITALLY REMASTERED. Worst part is that they sounded terrible compared to the original pressings and basically killed hi-fidelity mastering.

Many years back, Earache Records started re-issuing albums remastered with full dynamic range...so what are we supposed to do with the old re-masters...throw them away?:mad:. Last year Iron Maiden has re-released their discography with the same compressed mastering they released in 1998. The difference?... they come with an action figure and a patch :rolleyes:.

I am starting this post by saying that i dont like compressed sound. By compression, i did not mean file compression that we achieve by compressing a CD format to an mp3 format. What i meant by compression is in context to how audio is recorded in a media.

By definition compression tend to make soft sound loud and loud sound soft. This is useful to get all the sound a similar level during recording. But it looses in its sense the realism of what is been played / recorded. Some amount of compression is nice , good. But over compression is very bad.

Whenever i listen to the bollywood recordings of the 50s, 60s,70s and 80s i can find that the recording sound very real as there was "No" compression of audio signals those days and everything was recorded live as-is. So the instrument size and scale were easy to recognize with them. For instance violin sounded like violin in sound, size and scale and so did a base guitar or a saxaphone. These recordings can be seen from those of Naushad, Bappi Lahari or RD Burman types of music.

Coming to the compressed era or what i call ARRehman type of music, there is a case of lots of over compression. Everything sound too flat and detailed that you loose sense of the instrument size. Though it would be pleasing to listen them in literal sense but there is no sense of realism in the music as everything sounds same level. Agreed the instrument sizing is not a big deal for a casual listner or a background listner but for critical listner they do matter. For those who listen to music when parallel preparing an office presentation on their laptop on a Sunday evening for an early Monday morning meeting they wont even care for the compressed sound where more than 95% of the music listener currently are. So the industry cater to those ccustomers and dont even care of the rest of 5% of the listeners. To top it these over compressed recorded audio are boosted in level double or tiple time to win on the loudness war (most punjabi type rap songs of the current era)

I have also observed that some audio gear tend to compress the sound. It can be amplifier, source or even speakers. They tend to sound very flat to any type of music and there can be many reasons for that which is out of scope of this discussion.

I have listened to the AV Receiver designed by hfv FM Ravindra Desai who i believe use some kind of compression in his design by choice to make it flat sounding to all level of music. (though i am not sure).

Disclaimer: The above is entirely my own opinion and others may choose to differ.
Great post Hari. I completely agree with you. Because of the loudness war, we cannot listen to our favorite artists they way they are meant to sound:(. Lots of mastering engineers have signed petitions against this but it seems to be in vain. Another thing I have noticed is that mastering overall these days whether on vinyl or CD, is very bright in comparison to the old days leading to listening fatigue.

I too don't like word compression, the compression process started since digital era came into force. If you like music of post 90s there is no issue of compression (digitally), but early 90s music never play great if compressed.
People who don't like compression and serious old music enthusiast have already moved back to Analog audio.
that's the reason why Analog audio getting slowly on track.
Yes...this is definitely one of the reasons for the vinyl resurgence, even though 90% of the vinyl released today is from digital sources
 
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keith_correa

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I have also observed that some audio gear tend to compress the sound. It can be amplifier, source or even speakers. They tend to sound very flat to any type of music and there can be many reasons for that which is out of scope of this discussion.
Can you please name gear that you have observed compresses sound? I wonder why they would do that. o_O
 

Surrealistix

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Lots of amps used to do it
Remember the loudness button on many Japanese IAs
Cheers,
Raghu
I don't think the loudness button compresses sound in the same way that compression is used and abused during the mastering process.

The loudness button mainly boosts bass to help with improving the perceived bass levels at low volumes (see Fletcher–Munson curves). I think, If done right, the Loudness button could be a pretty useful tool for listening to music late at night. Having said that, I do have a loudness button on my pre-amp, but I don't like the way it sounds.
 

hifitoaster

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Lots of amps used to do it
Remember the loudness button on many Japanese IAs
Cheers,
Raghu
That loudness button is meant to do the opposite of compression, in a weird bad way. Boost the bass, boost the treble, so that you can HEAR the highs and lows at a lower volume. Normally we hear more of midrange at lower volumes without the loudness button. ;)

The loudness war thing has lot to do with change of nature of listeners. Till end of 90s ppl there were lot of folks sitting between two speakers to listen to their music. Then hometheatre and movies killed music listening hobby for many that it only became a passive hobby (like a background thing) to other hobbys or work. Equal loudness means, even with passive listening u hear everything, and its sounds more fuller even if u are not sitting in between speakers. I really hate it though like many of us. Pop is horrible these days. Really miss those quality recordings from 80s and 90s. By the way, which AR Rahman song sounds compressed?
 
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raghupb

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Using F-M curves to adjust sound on user equimnet or to tinker at source do essentially the same thing to sound output.
It is all EQ techniques, robbing the user of the intricacies of sound and music.
DRC is a method to tinker at source, when the material is mass produced.
Loudness control is a end user equipment. In a way even tone controls do this.
But then tone controls give the user much more flexibility; so does tone defeat.

When hearing via tinny headphones or earphones, some amount of EQ is desired.
But DRC took it to the extreme in many cases, so much so that the original recordings sounded bloated or wimpy.

Cheers,
Raghu
 
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jls001

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The need to be the loudest sounding radio station (mainly USA) was what prompted hot cuts.

Actually the process is "companding", compression and expanding, not compression alone. It basically involves pushing down the amplitude of louder components of music and boosting the amplitude of quieter components so that there will hardly be much dynamic variation and the music will be uniformly loud. The waveform of the envelope of such music on a DAW will look more like a rectangular waveform than a natural music waveform envelope. Such a waveform was useful for FM stations which allowed them to play loud without crossing their permissible modulation thresholds. If a station over-modulates, it exceeds it allocated bandwidth and may interfere with other nearby stations. The intermodulation products can harm both itself and neighbouring channels.

For the music buying public the only solution is to carefully choose what one buys.
 

ramanips

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Am using Dynamic Range Expanders like DBX 3BS And its digital version DBX 3BX-DS and pioneerr rg-1 for Compressed audio and internet stations
they give fantastic results.
They give v.good results to Vinyl too.
there are others like Phase Linear 1000 ,Pioneer RG9,RG60 Etc.
 

Hari Iyer

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Can you please name gear that you have observed compresses sound? I wonder why they would do that. o_O
Keith, I don't remember any brand names now, but have observed during some of my casual listening sessionns. You need to observe i if the setup is able to scale up and down with the pitch of the music and are the energy level realistic. A good comparison will be to listen a live performance and compare it with that.
 

flat_listener

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Experienced engineers will often talk about how one compressor is more “musical” than another.

Audio compression is one of your most powerful mixing tools. It’s the essential element behind every good mix.
But to make your compressors work, you need to understand compression first.

It’s intimidating to start learning such a huge subject, especially when the controls and their effect on your signal are difficult to understand depending on your sound.
 

amit11

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I don't think the loudness button compresses sound in the same way that compression is used and abused during the mastering process.

The loudness button mainly boosts bass to help with improving the perceived bass levels at low volumes (see Fletcher–Munson curves). I think, If done right, the Loudness button could be a pretty useful tool for listening to music late at night. Having said that, I do have a loudness button on my pre-amp, but I don't like the way it sounds.
I too agree, if F-M implemented correctly it is good for listening at low volume levels. Here also we have two things, one is the normal equalizer which is static. And another is active equalization. This is done in real time based on the actual volume vs the static.
When static equalizer is set to sound good, and post that if we increase the volume or decrease the volume we can feel the balance has changed.
However when active equalization is there, it re-adjusts in real time with the actual volume and we feel the same original balance. I first observed it in my bose sound dock. (Battery powered)
 

sound1

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I read somewhere that one of the common applications of DRC was to ensure that all nuances of a drum was captured so that people could enjoy them on their modest hi-fi systems. I can't find that video unfortunately but here is something which demonstrates what happens if the 'raw' sound is recorded vs a compressed sound which conveys a lot more details with a little bit of dynamic range sacrifice:

EDIT: Found it
 

Nikhil

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It's a pity to see what has become endemic in the audio industry today.

Any of the old music albums up until the 90s have Dynamic Range of 15 - 17 or more. Today almost anything is in 5 - 6 range. It's so easy to hear and see (in software) if you compare any older music with their new "remastered" versions. The sad part is that the very people who are supposedly the guardians of music are the biggest perpetrators - A R Rahman famously wanted all instruments on his recordings to be of the same level.

Unfortunately I don't see anything that's going to change things for the better. With casual listening dominating the industry there is just no reason to do things any different. Recently I tried to engage with someone recording some really nice Indian classical music - with a DR of 11! I tried to explain to him to "let the music be" but they vehemently denied the effects of dynamic compression.

If you ask me - hold on to your old original recordings. The new stuff is junk.


.
 

keith_correa

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Any of the old music albums up until the 90s have Dynamic Range of 15 - 17 or more. Today almost anything is in 5 - 6 range.
Recently I tried to engage with someone recording some really nice Indian classical music - with a DR of 11!.
What are these numbers?
If you ask me - hold on to your old original recordings. The new stuff is junk.
See # 3 below.
~~~~~~~~~~~~~~~~~

1. It IS "Compression". It's compression of the dynamic range! There are mainly 2 methods implemented - downward compression and upward compression. Compression is NOT always bad - it depends upon how it's implemented.

2. #1. is done to increase loudness peak levels - this is known as the "loudness war"

3. Contrary to belief, the "loudness war" is not a relatively recent phenomena. It existed and was implemented from the 1940's onwards. If anyone thinks that the recordings one possesses that was recorded before a time threshold was not mastered with DRC - you may need to think again! It's only after the advent of the CD that this became widely known and prevalent but it existed way before the CD/80's/90's.
 

raghupb

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@keith_correa
DRC has always been there in the recording industry.
When hi-fi made its appearance in the early 60s, studio engineers had more flexibility to play around with sound.
Without DRC, an old record with very quiet and very loud passages in the content would be hard to render (western classical is a good example).
When digital hi-fi went personal/portable, to accommodate earphones and smaller music players, DRC made a very aggressive comeback.
The numbers FM @Nikhil refers to are the difference between the quieter/louder passages in music content.
Cheers,
Raghu
 
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