Topic: Korg MR-1000

[MattH]

Matt,

Is there anyway that you might be able to post an audio clip of the affected audio?  And this occurs only when converting to 16/44.1 using audiogate?  The 1/5.6M files sound ok?  I recorded a band, Chicago Afrobeat Project, last weekend in 1/5.6M and the conversion to 16/44.1k was sounded fine.  Does the 1/5.6M file sound normal on the computer after transfer via USB?  Let us know what you find out.

+T for your troubles.

JC

Upon further analysis, I believe the problem is mainly the mic input brickwalling. And secondly the fact that 16/44 doesn't sound anything like 1-bit/5.6
The brickwalling is not very noticeable at 1-bit/5.6 but looking at the 16/44 waveform appears obvious and sounds much more distorted than at 1-bit. Not sure why. I guess I will be using an external pre most of the time now.

[WiFiJeff]

Looking at my results today, I have good news and bad news, the latter in two trenches.

The good news is that this machine sounds damn good, playing back the DSD from the headphone jack, definitely great sound from a classical grand piano, in spite of the bad news, which is:

The somewhat bad news is that I can confirm Matt's findings on brickwalling.  I was using a Josephson C617 with LD caps for the grand piano, at about 6 feet away.  With low setting , the preamp overloaded (I now estimate you can't turn the volume below 10 o'clock without risking brickwalling, I had it around 8 o'clock).  The sound on playback from the MR-1000 was not awful, but converting it to wav certainly loused it up.  This may be salvageable with improvements to AudioGate, I'd hate to have to go analogue-out of the Korg to another recorder to fix it.

The really, really bad news is that in transferring the dff files to my computer I got a cyclical redundancy check error, and one file wouldn't transfer.  This is something I've seen on badly burned DVDs, never from the hard drive of a 722 or a MiniR82.  Playing that file portion back on the Korg, it burps at ~4 minutes in and repeats some measures four or five times, then gives me a hard drive busy error message.  This was during the first of three files that recorded a Brahms sonata without any operator intervention, the second and third files are fine (except for brickwalling), so I expect that most of the first file is there too, if there is some way to fix the error at ~ 4 minutes in.  Korg guy here?

Jeff

[SClassical]

You need to PM Jerry and remind him to read what you stated. Also post it in www.korgforums.com and PM him there, too.

[Colin Liston]

You need to PM Jerry and remind him to read what you stated. Also post it in www.korgforums.com and PM him there, too.

Well after reading the Korg forums sounds like Korg jumped the gun by releasing this too soon.  How can we find out of they are working on these problems?
Jerry, can you find out if these issues are known to Korg?

For those that are interested, Korg forum link:

http://www.korgforums.com/forum/phpBB2/viewtopic.php?t=23233&highlight=mr1000

[jerrythek]

Looking at my results today, I have good news and bad news, the latter in two trenches.

The good news is that this machine sounds damn good, playing back the DSD from the headphone jack, definitely great sound from a classical grand piano, in spite of the bad news, which is:

The somewhat bad news is that I can confirm Matt's findings on brickwalling.  I was using a Josephson C617 with LD caps for the grand piano, at about 6 feet away.  With low setting , the preamp overloaded (I now estimate you can't turn the volume below 10 o'clock without risking brickwalling, I had it around 8 o'clock).  The sound on playback from the MR-1000 was not awful, but converting it to wav certainly loused it up.  This may be salvageable with improvements to AudioGate, I'd hate to have to go analogue-out of the Korg to another recorder to fix it.

I spoke to the engineers about the potential for brickwalling and got this info:

It seems like the output voltage of the mic fed into MR-1000 was too high and the signal was clipped in the gain amp in the input stage of MR-1000. The supply voltage of the op-amp is set to +/-6V (12Vp-p), which may have input signals above 120mV clipped.

The sensitivity of Josephson C617 is listed as 66 mV/Pa (-24dB ref 1V/Pa). It is so high compared to other mics out there, and it can exceed the clipping level of MR-1000.

Another "sensitive" mic that may cause such problem would be DPA Type 4041-SP; 65 mV/Pa (-26 dB ref 1V/Pa).

So this is about the matching up of the right gear to the specifications and performance of the recorder. Changing something in AudioGate can't help what has already been recorded with this type of problem.

The really, really bad news is that in transferring the dff files to my computer I got a cyclical redundancy check error, and one file wouldn't transfer.  This is something I've seen on badly burned DVDs, never from the hard drive of a 722 or a MiniR82.  Playing that file portion back on the Korg, it burps at ~4 minutes in and repeats some measures four or five times, then gives me a hard drive busy error message.  This was during the first of three files that recorded a Brahms sonata without any operator intervention, the second and third files are fine (except for brickwalling), so I expect that most of the first file is there too, if there is some way to fix the error at ~ 4 minutes in.  Korg guy here?

Jeff

This sounds more like a bad sector on the hard drive or some other error of that type. I'll PM you to get more info.

Regards,

Jerry

[WiFiJeff]

So this is about the matching up of the right gear to the specifications and performance of the recorder. Changing something in AudioGate can't help what has already been recorded with this type of problem.

The very odd thing is that both Matt and I, who experienced this brickwalling, are convinced that the MR-1000 playback of the DSD file sounds okay, or with only minor issues, while the pcm conversion is really ugly. 

Looking forward to your pm on the hard drive sector issue, hope this is recoverable or at least avoidable in the future with the proper magic words.

Jeff

[guysonic]

So this is about the matching up of the right gear to the specifications and performance of the recorder. Changing something in AudioGate can't help what has already been recorded with this type of problem.

The very odd thing is that both Matt and I, who experienced this brickwalling, are convinced that the MR-1000 playback of the DSD file sounds okay, or with only minor issues, while the pcm conversion is really ugly. 

Looking forward to your pm on the hard drive sector issue, hope this is recoverable or at least avoidable in the future with the proper magic words.

Jeff

Don't know if this applies in particular, but noticed that working 32bit depth in software with 16/24bit depth recordings, sometimes some processes (like frequency boost, etc) amplify the signal to EXCEED 16/24bit depth if directly converted back to lower original bit depth.  I have seen converted files get clipped using CEP if not NORMALIZING to desired <16/24 bit depth FIRST BEFORE making the bit depth conversion.

In your situation if I understand these posts, the original recording is DSD with potential for VARIOUS rate AND bit depth CONVERSIONS to PCM type files.   AND your original DSD recording sounds OK BEFORE CONVERSION? 

If this is true by the two reports of hearing a good unclipped recording, but then gets clipped upon file conversion, then it seems to me your conversion software may have a bad WORKFLOW scheme or something needs to be added to it for conversions to not get clipped? 

[MattH]

Looking at my results today, I have good news and bad news, the latter in two trenches.

The good news is that this machine sounds damn good, playing back the DSD from the headphone jack, definitely great sound from a classical grand piano, in spite of the bad news, which is:

The somewhat bad news is that I can confirm Matt's findings on brickwalling.  I was using a Josephson C617 with LD caps for the grand piano, at about 6 feet away.  With low setting , the preamp overloaded (I now estimate you can't turn the volume below 10 o'clock without risking brickwalling, I had it around 8 o'clock).  The sound on playback from the MR-1000 was not awful, but converting it to wav certainly loused it up.  This may be salvageable with improvements to AudioGate, I'd hate to have to go analogue-out of the Korg to another recorder to fix it.

I spoke to the engineers about the potential for brickwalling and got this info:

It seems like the output voltage of the mic fed into MR-1000 was too high and the signal was clipped in the gain amp in the input stage of MR-1000. The supply voltage of the op-amp is set to +/-6V (12Vp-p), which may have input signals above 120mV clipped.

The sensitivity of Josephson C617 is listed as 66 mV/Pa (-24dB ref 1V/Pa). It is so high compared to other mics out there, and it can exceed the clipping level of MR-1000.

Another "sensitive" mic that may cause such problem would be DPA Type 4041-SP; 65 mV/Pa (-26 dB ref 1V/Pa).

So this is about the matching up of the right gear to the specifications and performance of the recorder. Changing something in AudioGate can't help what has already been recorded with this type of problem.

The really, really bad news is that in transferring the dff files to my computer I got a cyclical redundancy check error, and one file wouldn't transfer.  This is something I've seen on badly burned DVDs, never from the hard drive of a 722 or a MiniR82.  Playing that file portion back on the Korg, it burps at ~4 minutes in and repeats some measures four or five times, then gives me a hard drive busy error message.  This was during the first of three files that recorded a Brahms sonata without any operator intervention, the second and third files are fine (except for brickwalling), so I expect that most of the first file is there too, if there is some way to fix the error at ~ 4 minutes in.  Korg guy here?

Jeff

This sounds more like a bad sector on the hard drive or some other error of that type. I'll PM you to get more info.

Regards,

Jerry

Sure, a few mics are very sensitive and could produce clipping at relatively low SPL's. I think the problem here is most mics may produce MR-1000 clipping at relatively high SPL's which is a big problem for loud PA taping without an external preamp.

[WiFiJeff]

[

In your situation if I understand these posts, the original recording is DSD with potential for VARIOUS rate AND bit depth CONVERSIONS to PCM type files.   AND your original DSD recording sounds OK BEFORE CONVERSION? 

If this is true by the two reports of hearing a good unclipped recording, but then gets clipped upon file conversion, then it seems to me your conversion software may have a bad WORKFLOW scheme or something needs to be added to it for conversions to not get clipped? 

The preamp overload certainly happened, I could see the meter maxing out at -6 dB, but when I listened to the DSD playback on the MR-1000 with headphones I breathed a sigh of relief as the damage didn't seem too bad, but I wouldn't say it sounded "OK" as in "perfect". I was also taping with a 722 and Neumann mics, and the 722 meters showed that things only went max maybe 3-4 dB higher than the brickwall.  It's only on conversion to pcm (I tried 16/44.1 and 24/96) that it sounded really ugly.  That sounded much like what Matt described.

Jeff

[guysonic]

[

In your situation if I understand these posts, the original recording is DSD with potential for VARIOUS rate AND bit depth CONVERSIONS to PCM type files.   AND your original DSD recording sounds OK BEFORE CONVERSION? 

If this is true by the two reports of hearing a good unclipped recording, but then gets clipped upon file conversion, then it seems to me your conversion software may have a bad WORKFLOW scheme or something needs to be added to it for conversions to not get clipped? 

The preamp overload certainly happened, I could see the meter maxing out at -6 dB, but when I listened to the DSD playback on the MR-1000 with headphones I breathed a sigh of relief as the damage didn't seem too bad, but I wouldn't say it sounded "OK" as in "perfect". I was also taping with a 722 and Neumann mics, and the 722 meters showed that things only went max maybe 3-4 dB higher than the brickwall.  It's only on conversion to pcm (I tried 16/44.1 and 24/96) that it sounded really ugly.  That sounded much like what Matt described.

Jeff

Seems to me by your impressions listening to the raw DSD on the deck there's ADDITIONAL headroom maybe even above 0 dBm where clipping doesn't occur, and who had done tests to verify the accuracy of the VU indication?  No tests of this kind have been done on MR-1 or 1000 as far as I know, even with several here suggesting somebody do this. 

Also, maybe some DSD 'headroom' is LOST when converted to PCM.  Does Audiogate software have a feature to AMPLIFY by -3 to -6 dB?   

Maybe try this if hearing clipping on converted files or maybe you've 'pushed' recording levels using inaccurate VU indications (pushing levels seems NOT so needed with 24bit/DSD recording modes) so DSD to PCM conversions are well inside 'clipped' maximums; then listen to the converted to PCM files for sounding more like DSD original did on the deck.

[WiFiJeff]

Clipping is another issue, it is indicated that you get 3 dB more headroom in DSD and if you use it you have to take the conversion to pcm down by -3 dB, which is possible in AudioGate.  But I was not clipping, far from it.  The meters never went above -6 dB because they were brickwalled there, even if not by a whole lot.  Taking levels down 3 dB in DSD-to-pcm just produces a brickwalled pcm at -9 dB.  So I don't understand why the brickwalling sounds worse in pcm (all resolutions I've tried) than on the MR-1000 playback.   Maybe it's an illusion from my playback equipment.  What I'll try next is analog-out from the MR-1000 to my SD722, and burn a CD with 1) the Audiogate pcm'ed version of the file and 2) the 722 recording of what I hear on the MR-1000, and play those back on the same setup.  Only if they sound different then will I be sure there's an issue here.

Jeff

[guysonic]

Clipping is another issue, it is indicated that you get 3 dB more headroom in DSD and if you use it you have to take the conversion to pcm down by -3 dB, which is possible in AudioGate.  But I was not clipping, far from it.  The meters never went above -6 dB because they were brickwalled there, even if not by a whole lot.  Taking levels down 3 dB in DSD-to-pcm just produces a brickwalled pcm at -9 dB.  So I don't understand why the brickwalling sounds worse in pcm (all resolutions I've tried) than on the MR-1000 playback.   Maybe it's an illusion from my playback equipment.  What I'll try next is analog-out from the MR-1000 to my SD722, and burn a CD with 1) the Audiogate pcm'ed version of the file and 2) the 722 recording of what I hear on the MR-1000, and play those back on the same setup.  Only if they sound different then will I be sure there's an issue here.

Jeff

You may be dealing with two clipping problems, one from first stage analog overload during recording, and later with additional clipping from conversion process that made the converted file sound even worse?

[Nick's Picks]

how about running a pad on the deck ?
does it have one ?

[newblue]

The MR-1000 has a limiter switch plus the high and low gain settings.

From reading Jeff and Matt's posts (and Jerrys fwiw),  until someone wants to do a 'ACM' style mod [cough]Doug[/cough] the MR-1000 is not going to be a very reliable 1-box-solution.  I'm happy with the V2 in front of the MR-1000, it sounds excellent, but it'd be even cooler if it was a viable 1-box-soln.

From Jerry's post, 'it's designed the way it's designed and you haven't found the right microphone to use with the deck'. pptttthhhhbbbb.  No problem with the deck, just the mics are too sensitive.  Where do I enroll my MR-1000 for sensitivity traning?

[WiFiJeff]

From Jerry's post, 'it's designed the way it's designed and you haven't found the right microphone to use with the deck'. pptttthhhhbbbb.  No problem with the deck, just the mics are too sensitive.  Where do I enroll my MR-1000 for sensitivity traning?

Yeah, I had that thought too, but I lived happily with the Sony M1 for many years, first attenuating the signal from DPA4060s, then using the MMA6000, so I can live with the sensitivity issue now that I know it's there.  And I assume there will be mods for the Korg box that will fix the preamp (as mentioned, there is no pad on the Korg input, and the Josephsons don't have one either, my AKG has a 10 dB pad but that may not be enough).  I am waiting for Jerry's pm on the hard drive error issue, that is more of a killer for me, if it can be reliably fixed forever I am hooked on the Korg.

Jeff