KVR Audio

Krakatau · Post by **Krakatau** » Sat Sep 23, 2006 8:53 am

Out of curiosity

I'm amazed by one typical artifact resulting of mp3 encoding,,,,

( and as much i can judge in other analysis/resynthesis methods )

...that seems to smooth the attack of percussions, much in the highest frequencies through their harmonic content, without adding any coloration

Especially on cymbals, this is very spectacular

Seems to be an interesting effect in itself and i'm wondering if their are in the actual huge plug-in arsenal many effects able to recreate it ?

orangesuite · Post by **orangesuite** » Sat Sep 23, 2006 9:23 am

not directly that i know of but you could try and encode at a shit rate and then use voxengos' MSED plug to bring out the crapness.

tetraplan · Post by **tetraplan** » Sat Sep 23, 2006 10:41 am

You could try and use KTgranulator to get similar effects. Experiment with settings and grain count.
You can get the warbly effect of poorly encoded mp3s by setting the transpose to two values.

Groet, Erik

sonicfire · Post by **sonicfire** » Sat Sep 23, 2006 11:30 am

That's funny, i always thought of the same

Krakatau · Post by **Krakatau** » Sat Sep 23, 2006 5:30 pm

thanks for the input folks, i think in particular that this artifact that smoothes the impacts very interesting and would deserves to be turned to an effect as itself, especially considering it transparency in regard to the timbral aspect that strictly remains the same

Did you notice this ?

mistertoast · Post by **mistertoast** » Sat Sep 23, 2006 5:52 pm

How about encoding something with mp3 and then decoding it, then subtracting the processed sound from the original?

sonicfire · Post by **sonicfire** » Sat Sep 23, 2006 5:52 pm

mistertoast wrote:How about encoding something with mp3 and then decoding it, then subtracting the processed sound from the original?

Nice Idea

This way you could "control" the amount of encoding noise

cron · Post by **cron** » Sun Sep 24, 2006 2:15 am

Most encoders tend to low pass the signal before encoding when using low bit rates. Typically 16kHz for 128k. I'd hazard a guess that what you're hearing is related to this, since most (all?) analysis/resynthesis procedures cope with the high end much better than the low. Cymbals do indeed have prominent partials in this area, so perhaps what you're hearing is the low pass taking the 'edge' off the sound.

Kim Lajoie · Post by **Kim Lajoie** » Sun Sep 24, 2006 2:22 am

One way to approximate the effect of mp3 encoding/decoding is to use a spectral gate or spectral expander. Used subtly, it can add that shiny ringing...

-Kim.

Krakatau · Post by **Krakatau** » Sun Sep 24, 2006 5:02 am

yeah right, that's what i suspect about spectral effects,

at another dregree,but more extreme Spectral monkeyage seems to have a somehow similar rendering

Some time stretch algorithms too :

on Amazing slow downer , one of the algo has a similar artifact ( even without stretching an audiofile )

Krakatau · Post by **Krakatau** » Sun Sep 24, 2006 6:39 am

By listening carefully, i would descriped it as the instantaneous, impact of a cymbal especially ,is turned to a kind whipped sound from it lowest to highest frequencies

I can figure out that a dynamic low-pass filter would do something approaching on a single cymbal shot , or a cymbal at a certain degree, but not in a mix...

I' ll try to create some significant examples later if i can find the time to do a serious job

Krakatau · Post by **Krakatau** » Sun Sep 24, 2006 9:25 am

ok

here i go :

2 examples, each with an original 16bits/44.1Hz wave files and its 128 kbps mp3 encoded counterpart

at first :

www.anak-krakatoa.net/~downl/misc/artifacts/1.wav

www.anak-krakatoa.net/~downl/misc/artifacts/1.mp3

In this first example comparing both files, just notice, as other instruments and arrangements remains the same how, how the hi-hat is changing character
The "flutes" are also affected, but this is not such spectacular because of the natural smoothness of their attack

in second :

www.anak-krakatoa.net/~downl/misc/artifacts/2.wav

www.anak-krakatoa.net/~downl/misc/artifacts/2.mp3

Here i just want you to notice on how the sustained synthetic sound on the last measures is behaving after encoding
Something that reminds a heavy chorus or a detuning effect created with a pitch shift ( like mda detune ) and others organ-like sustained harmonies seems also slightly affected
( other percussives sounds are also quite affected, most of them because they where themselves heavily threated in a previous time, ...maybe revealed byt the encoding limitation ? )

I' m just wondering if this artifacts is revealed only inside such an overall mix or if it would sound the same applied on these tracks individually, apart of the whole orchestration ?

fred-hal · Post by **fred-hal** » Sun Sep 24, 2006 9:30 am

connection timed out..

Krakatau · Post by **Krakatau** » Sun Sep 24, 2006 9:36 am

fred-hal wrote:connection timed out..

...in other words ?

fred-hal · Post by **fred-hal** » Sun Sep 24, 2006 9:41 am

Your site timed out, and no sound came out of my speakers..

mp3 artifacts used as effets ? ( two examples inside )