Topic: Korg MR1, WTF??? SOS

[Church-Audio]

I took my MR1 for a ride this afternoon, setting up a pair of Josephson C617s with Gefell large diameter caps (MK102.1), baffled with GuySonic's "LiteGuy" going into an SD722, with the unbalanced analog tape-out from the 722 going to the Korg.  Both recordings sound great, but when I went to compare them in Wavelab I got the following:  the 722 recording at 24/192 looks like a normal tape, but the MR1 DSF recording run through AudioGate to be 24/192 wav, though it sounds fine, comes out looking fat and fuzzy, even the silent parts have a fuzz that runs to almost 50% of the signal though I hear nothing.  Looks like some sort of low frequency artifact, but when I tried exporting the DSD from Audiogate at 16/44.1 it looks normal.  At 24/96 the fuzz is faintly there, the silent parts not quite a nice line like the direct 722 tape and the 16/44.1 export.

Anybody got a clue what this is?  Or how to get rid of it?  Anyone else try exporting to 24/192?

Jeff

Hi Jeff,
It sounds to me like the conversion to PCM is not applying any anti-alias filtering.

I don't know too much about DSD, but PCM requires filtering to remove frequencies that will wrap. What makes me think that this is it, is when you mentioned sample rate conversion to 44.1 which sounds fine. And applying eq at 20kHz makes it sound ok also.

What happens when you take the 192kHz file and sample rate convert to 96Khz ?
(All SRC requires filtering as does any A>D pcm sampling)

Gordon

P.S. The other possibility is that DC offset is also involved. Typically I think, low frequency filtering solves this problem, but if present in your audio, it could be coming back as an alias high frequency after conversion to pcm. (Just a guess, of course.)

I think it might be that there is a high pass and low pass but because of the wide sampling rate they are much lower then the normal 44.1k that we are used to hearing so you might have something that is producing low frequency noise that you never noticed before but because of the extreme sampling rate are now able to hear.

[Nick's Picks]

remember,... there is more software out there than this hokey thing.  something will turn up.

[WiFiJeff]

I think it might be that there is a high pass and low pass but because of the wide sampling rate they are much lower then the normal 44.1k that we are used to hearing so you might have something that is producing low frequency noise that you never noticed before but because of the extreme sampling rate are now able to hear.

I record at 24/96 all the time and I don't think that is the issue.

The filtering is critical when downsampling.. This site is pretty interesting in that regard:

http://www.unipv.it/webcib/res_techtest_uk.html

This is truly eye-opening.  I'm not sure the Korg would have interested me at all if I saw the HUGE increase in noise levels out in the hf area.  Even at 192 wav direct it looks lame, but the Audiogate conversion is really bizarely bad, I wonder how much improvement better software would give. 

Jeff

[Church-Audio]

I think it might be that there is a high pass and low pass but because of the wide sampling rate they are much lower then the normal 44.1k that we are used to hearing so you might have something that is producing low frequency noise that you never noticed before but because of the extreme sampling rate are now able to hear.

I record at 24/96 all the time and I don't think that is the issue.

The filtering is critical when downsampling.. This site is pretty interesting in that regard:

http://www.unipv.it/webcib/res_techtest_uk.html

This is truly eye-opening.  I'm not sure the Korg would have interested me at all if I saw the HUGE increase in noise levels out in the hf area.  Even at 192 wav direct it looks lame, but the Audiogate conversion is really bizarely bad, I wonder how much improvement better software would give. 

Jeff

I think that there must be a way to get the software you have to work properly if not then this unit is junk I mean after spending $700 I want this thing to wipe my ass never mind sound good. So I hope its just an issue of something not setup right in the software. This might sound like a stupid idea but maybe you should uninstall the software and reinstall it? and then try recording again?

Chris Church

[WiFiJeff]

I think that there must be a way to get the software you have to work properly if not then this unit is junk I mean after spending $700 I want this thing to wipe my ass never mind sound good. So I hope its just an issue of something not setup right in the software. This might sound like a stupid idea but maybe you should uninstall the software and reinstall it? and then try recording again?

Chris Church

Same results with AudioGate on three separate computers!

Jeff

[it-goes-to-eleven]

I think that there must be a way to get the software you have to work properly if not then this unit is junk I mean after spending $700 I want this thing to wipe my ass never mind sound good.

Well said!  $700 does set extremely high expectations.

Whatever happened to the dude who has been hyping this thing for months - sight unseen - just because it has dsd?

As far as other dsd software... I've heard it is all insanely priced.. I hope someone discovers otherwise.

I believe it can record in native PCM.  Anyone tried that at 24/96 or 24/192?

[live2496]

I record at 24/96 all the time and I don't think that is the issue.

The filtering is critical when downsampling.. This site is pretty interesting in that regard:

http://www.unipv.it/webcib/res_techtest_uk.html

According to Gianni Pavan's graphs, the MR-1 is quite noisy when DSD is converted to 192kHz using the software. The noise level is up to -60db at 96kHz.

[Nick's Picks]

for me, the ability to do DSD>redbook and have it come out as nice as it appears to, is money well spent.
the .DFF files backed up for future use...i'm sure they'll come back into play eventually.

[it-goes-to-eleven]

According to Gianni Pavan's graphs, the MR-1 is quite noisy when DSD is converted to 192kHz using the software. The noise level is up to -60db at 96kHz.

The funny thing is... When I posted that I link I hadn't noticed that he has already added the MR-1 to the results!  I thought it was useful enough even without the MR-1 data..

The data show the Korg has issues even when recording to PCM...   I'd bet some money that if you took the Korg DSD and used the Tascam DSD>PCM software, you'd probably still see issues.. My gut says the problems here are not limited to just the audiogate software.  Just a hunch.

I don't have any skin in this game but someone who does should formally open a support case with Korg, cite those test results, and ask them what they're going to do.. Hopefully their response isn't to threaten the tester for publishing the data...  And if people wait patiently for a fix but the fix never comes, will they still issue refunds?

[Church-Audio]

I have a theory its still early and I am going to wait until I get the test file before I say this 100% but I think some of this noise is from the power supply on this unit. Lets face it all of these products use some form of charge pump power supplies to boost the battery voltage up to operate this unit. I think that some of this extra noise is or could be from this process. One way to find out is to create files that are 44.1 48k 96k 192k and then the highest sample rate and compare the signal to noise ratio. I would suspect that this increase in noise is directly proportional to the increased bandwidth due to the increased sample rates. Because of a noisy internal power supply. This is my best guess I hope I am wrong about this.

[live2496]

I have a theory its still early and I am going to wait until I get the test file before I say this 100% but I think some of this noise is from the power supply on this unit. Lets face it all of these products use some form of charge pump power supplies to boost the battery voltage up to operate this unit. I think that some of this extra noise is or could be from this process. One way to find out is to create files that are 44.1 48k 96k 192k and then the highest sample rate and compare the signal to noise ratio. I would suspect that this increase in noise is directly proportional to the increased bandwidth due to the increased sample rates. Because of a noisy internal power supply. This is my best guess I hope I am wrong about this.

Hello Chris,
I think the graphs show much better performance with the DSD recordings. It seems like the conversion process is what may be adding the noise.

Gordon

[it-goes-to-eleven]

I think the graphs show much better performance with the DSD recordings. It seems like the conversion process is what may be adding the noise.

Other than that, Mrs. Lincoln, how was the play? 

[Church-Audio]

I think the graphs show much better performance with the DSD recordings. It seems like the conversion process is what may be adding the noise.

Other than that, Mrs. Lincoln, how was the play? 

I need to get my hands on one of these to do some tests...

[WiFiJeff]

I am feeling a bit better, as the cello recital sounds pretty good on CD.  I went DSD > 24/96 by AudioGate, then edited in Wavelab and downsampled and dithered to redbook.  So I look forward to completing the piano recitals where a direct comparison with the SD722 will be possible.  I have done the 722 (at 24/192) as CD and DVD-A, and am doing the export of the DSD files now to 24/96. I'll send them out Monday to a friend with highend listening equipment.

The question I have, and won't be able to answer, is whether the DSD files will really represent something of quality going forward.  Or am I better off recording 24/96 or 24/192 with the 722 or Sonosax MiniR82, or even the Sony D1.

(Damn, this cello sounds sweet).

Jeff

[Nick's Picks]

the dsd files are really representing something of quality, yes.
its just the conversion that seems to be a little tricky.

try going DSD>CD direct.  i'm loving what i hear out of mine