Lossy compression, physcoacoustic models, and audio illusions.

[big_ee]

Listening to a 1971 Gershwin Concerto (1988 Rega Planer 3 ââ'¬â€œ Motor upgrade, RB300, rega wall stand, Dynavector dv10x / rega Mira / krystal kable / rega ear / cardas/ senn hd650) whilst sipping a nice glass of Tokay Pinot Gris, I was mulling over the posts that go something like:

ââ'¬Å"I put an ipod playing mp3, flac, wma, or whatever into someone's amp and they 'preferred' the sound of ipod to a high grade CD player, and it sounded 'just as good.' ââ'¬Â

The is clearly the case of someone not really listening, but they might have a point on the 'I prefer'.

It has got to be the Australian chardonnay effect.

To whit the physcoacoustic models, and algorithms that are used in lossy compression , are designed to make the music sound good. They would hardly be designed to make it sound bad.
Bit like a £/$ 5 Australian chardonnay, tastes good, not challenging but pleasant enough.

Listening to real music on a real hifi is more challenging. Bit like a great burgundy. Complex, delicate, temperamental I grant you. Better, Oh Yes. Grabs you by the B*LLs - Absolutely.

But hey if people prefer the ipod, good luck to them.

Anyway great to have found the forum.

ian

 

[garyi]

Well played Ian, you seem to be saying that iPods et all have their place in the hifi chain and should be enjoyed. However there is better quality available.

 

[Tenson]

I have been listening to a fair number of MP3s recently while trying to find new music I like. Frankly they sound **** to me! The better my Hi-Fi gets, the worse they sound. Sure the music is still enjoyable but I get the feeling I may have written some bands off simply because I couldn't really hear what was going on in the music and it sounded dissonant. Thats going to my external DAC as well so about as good as an MP3 could sound. Most of them are between 128kbs and 192kbs. Does the iPod sound like the iBook? ..cos thats audio output sounded **** too!

I don't think I have been so damning in a long time :JOEL:

Still I have been enjoying 'The Vanity Project' and 'Early November'

 

[garyi]

I usually download MP3s to see if I will like the music, I have discovered a few bands this way.

If you can't hear past the quality then I guess you refuse to listen to car audio, portable radios etc?

 

[Bob McC]

all have their place in the hifi chain and should be enjoyed

Like Amstrad presumably?

 

[michaelab]

To whit the physcoacoustic models, and algorithms that are used in lossy compression , are designed to make the music sound good. They would hardly be designed to make it sound bad.

They're not designed to make music sound good or bad, they're designed to make music sound like, well, music. The psychoacousting models used in developing the algorithms were used to determine what elements of the sound waveform could be removed or reduced without people noticing. One of these is that certain frequencies can be masked by others so removing the masked frequency is not audible.

Clearly there are limits to what extent you can apply the compression algorithms before they become significantly audible but it's certainly possible to lossily compress audio to some degree where the compression is totally inaudible. I don't know what that level is.

I'll certainly still take uncompressed or lossless compression over compression for non-portable listening

Michael.

 

[Tenson]

I usually download MP3s to see if I will like the music, I have discovered a few bands this way.

If you can't hear past the quality then I guess you refuse to listen to car audio, portable radios etc?

I will listen to a portable radio (I prefer to hear the engine in a car) but I feel no connection to the music. The emotional connection is one of the biggest factors for me and if I can't hear it due to poor quality then I can't judge if I like the music or not. The music I was thinking of is very complex with many layers so the MP3 just smudges it and there is no subtlety left.

 

[zanash]

I'm not certain that the design of the mp3 player has much to do with music pleasure, its more size and ease of use on the move. That said I do use one, it does sound ok with a back ground of a jet engine, bus tube, bike etc. Even my mother in law has one at nearly eighty ! but there not meant to compete or replace the humble cdp.....the record companise need to keep reinventing new sources so they can keep selling the same music over and over.

 

[garyi]

Thats a shame Tenson you are cutting yourself off from many ways of discovering music.

Presumably you are more into classical any how?

 

[big_ee]

Michaelab

I agree principally they are not designed to sound good or bad, but if you are apple, or Microsoft, or the guys who developed MP3, your principle aim is to develop compression which makes the compressed music sound the same as the original wav.
But if you want to shift more product you will tweak, in order to get the best out of the software, equipment, or whatever.

As well as physcoacustic modelling - Audio illusions, making the ear hear things that aren't there is part of it. + i bet there are all sorts of other patented and confidential modelling bells and whistles in there. To give them a usp. This is a multi million pound industry, after all.

On poor equipment like an IPOD a compressed 192 aac is difficult to distinguish from the uncompressed wav. And sounds 'good'

Uncompress it, and burn it onto a CD and play it through a decent transport, and the differences are immense.

In general

My issue is with dumbing down. The music industry would love to have 192kbps mp3/aac as the download standard, in fact it is a challenge to legally download anything else.
And i agree it's handy to have these for portable players, to hear a sample, or whatever. (Amazon samples are 32kbps mono btw!!!)

As they start to move away from CD, which is a frankly a compromise on Vinyl / Reel to Reel. You can bet they won't be pushing 1 GB uncompressed wav album file downloads.
The DAT that is used for mastering CD's these days has a 12 gb capacity so they are not stinting on production. Just distribution.

I dread to think what would happen to real Hi Fi if the source material we all listen to was only ever made available as a compressed file.

Paul van dyk, who is arguably one of the best DJs/ dance music producers on the planet has stopped using CD's and vinyl. All his gigs are done on his power book. I give CD's another 5 years, before they go the way of vinyl. Then what are we going to be playing new music on?

The LinnPod

 

[Tenson]

Thats a shame Tenson you are cutting yourself off from many ways of discovering music.

Presumably you are more into classical any how?

No I'm not in to classical very much. I like pretty much everything else though. Don't get me wrong I do listen to the music on MP3 and decide if I like it. However, it is no way to properly enjoy music. By the argument of 'well you should listen to the music not the quality' you could say hey stop listening to that portable mono radio and just read the sheet music! It doesn't matter about the quality of the performance its the music that counts.

The particular song I listened to yesterday was one by Further Seems Forever. It had a lot of electric guitars going full pelt but at the same time there are nuances in the background and you can hear the harmonic resonances caused by all the guitars playing together which plays a tune of its own. Armor for Sleep and Something Corporate are great for this and they have good recordings too. I couldn't really hear this in the MP3 though it just sounded like a loud guitar mess. I had to concentrate very hard to follow the music and decide if it had what I liked.