Monday, December 28, 2015

C64 SID shootout part 2.

Page has been updated with a nice music player, shouldn't any playback issue appear anymore \o/

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Thank you for all the feedback! Looks like the previous post is a big success so I decided to add some more info and details about the shootout.

The recording chain was 3 C64, connected one-by-one to the input of a RME Babyface soundcard with RCA cable. Recorded with default loudness settings, all input faders were on 0dB. Obviously, there's not much to set on the C64, so the signal simply flew to the input of the soundcard.

Recording software was Adobe Audition 3.0.1 (the best Audition version of all :) ).

In case you were wondering, yes, all of the recordings are clipping a bit - this means the signals from the C64 were too hot but not _that_ much. I wanted to keep the original signal so I didn't limit/compress/lower the volume.

Loudness level is different for each SID, the recorded waveforms are also quite different:


I edited the recordings and chopped them to smaller parts to show the significant differences between the SID revisions. Play the audio previews and listen closely. Each preview plays the same part/melody and I switch between SIDs at even beats.

The order is obviously R2-R3-R4-R4AR-R5 :)

Clip 01:



The second and third part (R3 and R4) sound like the SID is pushed to its limit and it's hard to generate the flute-a-like sound.


Clip 02:



Here, the most significant difference is the snare drum instrument. It sounds quite different in each version.


Clip 03:




Different filtering on the bass. The most remarkable is the last one, which is the 8580 R5 version. The sound is more opened (higher filter cutoff and wider LFO) so the *wow*wow*wow* sounds different a lot.


Clip 04:



Again, the modulation on the filtered bass sounds different. Very. Different. Also, did you notice the loud background noise during the second section? That's the noise of the R3 SID.


Side-note #1:
I'm not 100% sure about the SID revisions I have. According to http://sid.kubarth.com/ my 6581 R2 1485 might not be R2 but R3. But still, it sounds so different to the real R3 1585 that I tend to believe it's a real R2.

Side-note #2:
Please follow this download link if you would like to download the audio files in .OGG format. Let me know if you would like to listen to the uncompressed .WAV files too.

Side-note #3:
Why .OGG compressed audio files? Because they sound better than .MP3's with the same compression rate and need less disk space. Also, for this test the compression doesn't take much information about frequencies, the difference between SID revisions is still well-audible.


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