Harmonic distortion after OS 1.2.1 upgrade

[StephenKay]

Hi Stephen,
I tried putting the file to the FTP server but I got an error.

230 User elvis@karma-lab.info logged in.
ftp> bin
200 Type set to I
ftp> put O121TST1.zip
200 PORT command successful
550 Access is denied.
ftp>

Elvis Dowson

I don't know what to tell you. I just logged in, as you, and put a file into that directory - can you see it? Just some random .php file.

Is this the 313 mb file?

[StephenKay]

Maybe you need different commands. I'm using Fetch, on a Mac, and here's a bit from the transcripts log:

230 User elvis@karma-lab.info logged in.
SYST
215 UNIX Type: L8
PWD
257 "/" is current directory.
PASV
227 Entering Passive Mode (216,193,229,83,168,130).
LIST
150 Opening ASCII mode data connection for file list
226 Transfer complete.
PASV
227 Entering Passive Mode (216,193,229,83,168,182).
STOR avatar.php
150 Opening ASCII mode data connection for avatar.php
226 Transfer complete.
Upload complete at 10/12/06 8:06:24 PM

[elvisjohndowson]

Hi Stephen,
I just did an FFT comparision and there are clear differences between the two waveforms. Since I can't post an image here, I have put this on the karma-labs forum:

http://www.karma-lab.com/forum/showthre ... #post42561

The waveform in cyan is A114 Mega Mute Guitar resampled from a MIDI performance using OS 1.1.1.

The waveform in blue is A114 Mega Mute Guitar resampled from a MIDI performance using OS 1.2.1.


Elvis Dowson

[elvisjohndowson]

Hi Stephen,
I can see the avatar.php file on your ftp server. Let me try to install CuteFTP if I can find it and try again.

Elvis Dowson

[danatkorg]

Hi Stephen,
I just did an FFT comparision and there are clear differences between the two waveforms.

As noted before - this doesn't surprise me at all. Try recording the same sequence twice, into separate stereo pairs of audio tracks; I would guess that you would see the differences there as well, for the reasons I wrote previously.

- Dan

[elvisjohndowson]

Hi Dan,
I'll wait for your comments on this. It's 4.30AM here for me and I think I'll need to go get some sleep now. I've got quite a bit to do tomorrow!!

Elvis Dowson

[StephenKay]

If we're going to discuss the picture, I'll discuss it where the picture is:

http://www.karma-lab.com/forum/showthre ... #post42561

[danatkorg]

Hello all,

I've now spent the day looking into this issue.

First, I did a bunch of listening tests with two units side-by-side. I couldn't tell any difference. Then, I did a bunch of more controlled, recorded tests, as described below. I have all of these as WAV files, so I can upload them somewhere if anyone is interested.

Elvis mentioned three Combis:

A032 Monster Power Synth
B057 Feel the Rush
B068 Dust Storm on Mars

Interestingly, all three of these have some sort of limiting or saturation on the output. The latter two both use the St Tube PreAmp Modeling effect in the Total Effects - that is, strapped across the main outputs. This effect is designed to add saturation/distortion, and it certainly does so, especially on Dust Storm on Mars. This sound has noticable clipping when playing just four notes. This clipping goes away when individual track volumes are reduced (the master volume won't have much affect in this case, since it's post-TFX) or the Tube PreAmp is turned off.

I created a simple sequence using Dust Storm on Mars, and then made multiple recordings (5 passes each) on both OS 1.1.1 and 1.2.1. I recorded using internal bussing, so that A/D would not be a factor. I then imported the resulting WAV files into Peak, creating stereo files out of the native OASYS dual-mono files.

Finally, I listened to the stereo files. Within the 5 recordings for OS version 1.1.1, there were small variations in peak levels. I saw the same with the 5 recordings for OS version 1.2.1. There did not appear to be any overall difference in either level or sound between the two OS versions.

There could be many reasons for the small differences in levels. Candidates would include any non-note-on-synced LFOs, such as Program Common LFOs or effects LFOs; any random LFOs, random values in step sequences, random oscillator phase settings, or randomized oscillator scales; minute variations in sequencer playback; etc.

I also recorded a sequence on the Program that Elvis mentioned, INT-A 114 Mega Mute Guitar. I recorded this sequence under both OS 1.1.1 and OS 1.2.1. I can't hear a difference between the two.

My conclusion is that there is no audio difference between the two OS versions. I understand that Elvis honestly thought he heard a difference, although he was unable to audition the two versions side-by-side. Such perceptions can be caused by any number of things; also, perhaps he assumed that the clipping in Dust Storm on Mars was new. Such things certainly happen, and I firmly believe that his intentions were good.

For myself, I'm now satisfied that there has been no change in audio fidelity between the two versions. I am in the process of uploading the files to my iDisk; I'll post a message when the upload is complete, so that anyone who is interested can listen for themselves.

Best regards,

Dan

[danatkorg]

I've now uploaded the files to my iDisk, at:

www.homepage.mac.com/danphillips1

These are 48kHz 16-bit WAV files, recorded using the OASYS internal bussing (no A/D/A involved).

The Dust Storm Edit files use the same sequence as the other Dust Storm On Mars files, but edited to remove the Tube PreAmp effect, and with volumes lowered to avoid clipping.

Best regards,

Dan

[StephenKay]

Thanks Dan,
That's fairly comprehensive I believe.

Elvis,
You e-mailed me the two A114 Mega Mute Guitar WAV files, one from 1.1.1, and one from 1.2.1. Even though Dan has already said above that he thinks there is no difference, and put quite a bit of time into it (so I believe him), I did want to take the time to check your results. I know you also put a lot of time into this.

I created a new sound file that alternates between the two versions, and I cannot perceive any differences. You can view my full report at Karma-Lab, along with the alternating sound file:

http://www.karma-lab.com/forum/showthre ... #post42583

[thekeymaster]

Guys Ive gotta commend you all on this,ive been following this thread the last few days and I must say that is some hell of a breakdown on all parts.If anyone wants proof that users,developers and korg themselves want the OASYS to work then they should read this thread.

Its been like watching a mini team at work trying to find a conclusion.First rate.Well done.....(even though Elvis may still not be totally convinced) at least you've done your best to try and rectify his initial queries.

Excellent.

Neil

[elfrabo]

It must be quite stressfull to work at Korg these days: One person is convinced that sound quality is less with the new version and you must react quick to prove you are not guilty: It's sort of like being on trial where the public is the jury.

The Korg team has convinced me that sound quality is not affected by the new OS version: I will try out the new version for sure now...

[elvisjohndowson]

Its been like watching a mini team at work trying to find a conclusion.First rate.Well done.....(even though Elvis may still not be totally convinced) at least you've done your best to try and rectify his initial queries.

Hi Everyone,
I got up this morning at 9.30AM and read all the updates by Dan and Stephen. Thank you very much for trying this out from your side, both of you.

I was not able to download Dan's files for some reason. I was however able to download Stephen's alternating.wav file and even I could not tell the difference between the two samples from that file. There is something about the internal resampling to process, the difference is not apparent in those recordings.

However, I did try playing the same program on the keyboard at different velocity levels, light touch, heavy strike, etc, just to bring out the reverb component and it was there. To me the reverb component is quite readily apparent still, but it did not exist in OS 1.1.0 or OS 1.1.1.

I have faith in what Dan is saying and will trust his word and analysis.

However, I can still detect a difference when playing back that particular program live, i.e. an increased reverb component.

Now since I don't have two keyboards with me to perform a side by side comparision, I am planning to do two things:
a. Perform a full re-install to OS 1.1.1, once again and quickly listen to the program, default with all effects and then with all IFX/MFX/TFX turned off.
b. Take my OASYS unit to the local Korg distributor. They have an OASYS 76 on display. It is still at OS 1.1.0. I can then go and audition both the store unit and my unit at OS 1.2.1, side by side, through headphones and then check it.

Dan, I was just wondering, would it be possible for you to get a few more people involved and get the opinion of say 5 other people and see if they can detect a difference, to see if there is an increased amibient reverb for A114 between OS 1.1.1 and OS 1.2.1 at different velocities. If none of them can, then we can finally conclude this point.

Elvis Dowson

[elvisjohndowson]

Hi Dan,
By the way, regarding the calibration settings for my control surfaces, I when to the controllers page within a program and checked the on-screen display values for all the sliders as I moved them from its lowest position to the the highest position and the on-screen display showed that it was able to range from 0 to 127 for all the sliders. I guess this means that I won't need to calibrate my sliders, am I correct?

I also checked all the knobs and then also go from 0 to 127, although I'm not sure if they needed calibration to begin with.

The only thing I'm not so sure about is how to check the calibration for the joystick X and Y axis, the vector joystic X and Y axis and the ribbon controller. Do I have to record a song and then check to see the range of recorded controller value and see if they range from 0 to 127?

Elvis Dowson

[elfrabo]

Dan, I was just wondering, would it be possible for you to get a few more people involved and get the opinion of say 5 other people and see if they can detect a difference, to see if there is an increased amibient reverb for A114 between OS 1.1.1 and OS 1.2.1 at different velocities. If none of them can, then we can finally conclude this point.

Elvis Dowson

As I mentioned before: the Korg team has convinced me that there are no sound differences. Nevertheless I will listen to A114 before and after installing the update, but it's hard to compare this. I will let you know my opinion.