Problem with NPC and 24 bit files


#1

cant-believe-my-eyes-smiley-emoticon_gif

I have a problem with my NPC and do not know the cause. My PC is working under Windows 8 and I write and save files as PCM 24bit 192 kHz wav. My NPC is using firmware version .46. Recorded files play and look fine, but not long ago I noticed that when encoding files in flac the files size is less than other similar files compressed in flac (approx 1/2 the size). Now I think that the recorded files are not really 24-bit and contain only 16 bits of actual data. All the system settings on NPC and PC are correct. I tried three different recordings software - Sony Sound Forge, Audacity and Vinyl Studio but the result was the same. I also tried different USB cables but nothing changed.

I did an archive for these 3 files:

https://www.sendspace.com/file/7i6x2j

and one file taken with analog output of my NPC and recorded with RME soundcard for comparison:

https://www.sendspace.com/file/mrpaxz

Has anyone noticed this with their NPC? Perhaps other users are not aware of this issue.

I’ll be happy for any help beer_gif

P.S. By the way I tried record in 24/96 but the situation is the same.

Dmitry


#2

You can use either foobar2000 or dBpoweramp to verify whether your files are actually 24 bit. With foobar, right-click on a track, choose Properties, then switch from Metadata tab to Properties tab. dBpoweramp installs an Audio Properties tab that is visible when you right-click on an audio file in Windows explorer – I find this a very useful thing and IIRC it is included with the free version as well as the paid vesion.


#3

I know, but I think that the foobar2000 reads the statistics only from the file header.


#4

The files show as 24 bits. I think the question is whether the last 8 bits are empty. The same files are all about 3:45 in length. His FLACs are around 86 MB. For comparison, I looked at a 96/24 recording I had done on my NPC that is 3:51 in length. The AIFF file is 133 MB and the FLAC is 87 MB, about the same size as Dmitry’s but at half the sample rate. In contrast, a 3:46 192/24 file that I downloaded is 262 MB in AIFF and 153 MB in FLAC (FLAC created from AIFF using Max on a Mac). A 96-24 3:39 commercial download is 87 MB in FLAC (as downloaded) and 128 MB when converted to AIFF. The sizes of the files I recorded on my NPC at 96-24 seem consistent with commercial download sizes but you would think Dmitry’s 192/24 recordings would be significantly larger than my 96/24 recordings and more like my 192/24 downloads, but they are about half that size. (He does indicate that his 96/24 files are compressing more than would be expected as well so his FLAC files seem to be compressing more than mine even though both were recorded on NPCs using the same firmware.)

Any thoughts on why Dmitry’s 192/24 NPC recordings are compressing so much when converted to FLAC?


#5
jagmur said cant-believe-my-eyes-smiley-emoticon_gif

I have a problem with my NPC and do not know the cause. My PC is working under Windows 8 and I write and save files as PCM 24bit 192 kHz wav. My NPC is using firmware version .46. Recorded files play and look fine, but not long ago I noticed that when encoding files in flac the files size is less than other similar files compressed in flac (approx 1/2 the size). Now I think that the recorded files are not really 24-bit and contain only 16 bits of actual data. All the system settings on NPC and PC are correct. I tried three different recordings software - Sony Sound Forge, Audacity and Vinyl Studio but the result was the same. I also tried different USB cables but nothing changed.

I did an archive for these 3 files:

https://www.sendspace.com/file/7i6x2j

and one file taken with analog output of my NPC and recorded with RME soundcard for comparison:

https://www.sendspace.com/file/mrpaxz

Has anyone noticed this with their NPC? Perhaps other users are not aware of this issue.

I’ll be happy for any help beer_gif

P.S. By the way I tried record in 24/96 but the situation is the same.

Dmitry


When I decompress all of them and then recompress with flac I get approx. the same files sizes that you gave.

I analyzed five seconds at about 1:30 into all four files with Adobe Audition and they all had essentially the same spectrum.

The Audacity file seemed to have a lower volume setting for the first 45 seconds.

The Vinyl Studio file seems to have only 23 bits of active data.

The NPC Sound Forge has only 16 bits of active data.

The Audacity seems to have 24 bits of active data.

When I use the DS to play the data directly out of the NPC I always see the number of bits I’ve selected but that doesn’t prove that the bits have significant data in them. But the fact that they have different depths in different programs indicate setting in the program that’s recording more than the NPC - in particular Sound Forge from the RME is 24 bits but Sound Forge from the NPC is 16 bits. Are you sure you used the same settings?


#6

Yes, sure, I used the settings 24/192 on my PC and NPC and then I start the new record with same attributes. RME works perfectly with all software, so I think that it’s not my fault with settings facepalm-smiley-emoticon_gif


#7

This isn’t my area of expertise (still trying to figure out what that is) but whenever some writes that all their setting are correct, I recoil a bit - and that becomes the very place to look.


#8

I bet the recording software settings are not correct.

For example, in SoundForge, before recording you need to open the new file with the appropriate attributes for the project.

Thus, if you open a new file as 88.2/16 and send it an 88.2/24 signal to record it will truncate the last eight bits and record only in 16-bit.

I also suggest installing a VST bit-depth plug-in so you can monitor/check you are capturing a 24-bit signal. There are free ones available.


#9

Dmitry, one question I should have asked before is how much compression the software you use to convert WAV to FLAC is set for? For example, I do almost all of my conversions using Max on a Mac at FLAC compression level 5.


#10

What can I say, I’ve been doing a lot of experimentation and I could not do normal work with my NPC. I think this is a problem with USB Windows driver on my system . I have installed the plugin BitViewer for Sound Forge and did different experiments with system settings. I was able to discover that the bit depth can be was changed automaticaly from 16 to 24bit. Very little chance that someone can help me, but I was surprised with this fact.

I did an archive, in attached file the bit depth was changed automatically from 16 to 24bit at the point 0.06.

https://www.sendspace.com/file/007oqs

cant-believe-my-eyes-smiley-emoticon_gif


#11

I wish I had more ideas for you.

I doubt it is the driver. I continue to suspect it is a software setting.


#12

May I have a problem that my system is Windows 8 Russian localization? I noticed some errors in the instructions from my NPC with Russian translation.


#13

Step by step what I do with my NPC:

  1. USB cable was connected

  2. NPC power ON

  3. Chose 24/192

  1. the latest firmware on my NPC

  1. 24/192 NPC status OK

  1. Set NPC as recorded device in Sound Forge

  1. start a new record with following attributes

  1. That the my question “What I could do it wrong?”

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#14

Thanks for PSA support, now with the firmware 052 everything works perfect.

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#15

That’s great to hear!


#16

New trouble detected (firmware 052).

If I turn off the NPC which allready connected to my PC by the power button then my USB scanner, USB sound card go to offline mode and needed to restart. One of my USB devices (keyboard for 130$) died after such manipulations.

Who has the same problem? facepalm-smiley-emoticon_gif


#17

I had the same problem with recordings. The result of recorded files contain not real 24 but only 16 bits of actual data.
After updated the fw to .52 this problem seems resolved.

But!

When I connect the NPC via USB to my laptop on the display appear strange data 384/24b and I have to play with the laptop audio settings to get back the right digits.

npc11.jpg

Another issue when the PC is connected the display shows just …/24b at all settings although I choose 16 bit on audio card.


#18

This is fixed in 54, which should be released soon.

Dennis