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Author Topic: udial.ape uncovers resampler problems! solved in 11.0.88!!!  (Read 3989 times)

thomaspf

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udial.ape uncovers resampler problems! solved in 11.0.88!!!
« on: September 21, 2004, 06:14:20 pm »

Hi,

I was toying around with the DSP plugins in 10.0.155 and upsampled my CDs to 88.2 Khz and 24bits.

Just for fun I played the udial test file from hydrogenaudio.

http://www.hydrogenaudio.org/forums/index.php?showtopic=9772&hl=udial\.ape

The sample rate converter introduces a hude amount of noise. I am using an ESI Juli@ soundcard with ASIO.

I apologize if this has been discussed here before but is there something wrong with the resample. Could someone else try this out and report what they find.

Please be careful with the levels when you play back the file.

Cheers

   Thomas
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thomaspf

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Re:udial.ape
« Reply #1 on: September 22, 2004, 02:24:13 pm »

I did some more investigation into this and at this point I believe the problem is with the sample rate converter in MC!

I installed the latest version of the Shibata sample rate converter

http://shibatch.sourceforge.net/

and converted the udial.wav file to 24/88.2 and 24/96. The resulting files sound very good and clean. If I start with the 16/44.1 file and engage the built-in smaple rate converter to do the same thing the distortions are ear numbing!

Is there a chance that you could replace your resampler with the higher quality one?

Cheers

    Thomas
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pank2002

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Re:udial.ape uncovers resampler problems!
« Reply #2 on: September 22, 2004, 02:42:27 pm »

PLEASE, be very careful with this test. Do ONLY play it through headphones otherwise you may break your tweeter... not to mention ruining your hearing ability ::). My ears hurt so bad after having played it a couple of times.
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Matt

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Re:udial.ape uncovers resampler problems!
« Reply #3 on: September 22, 2004, 02:45:11 pm »

We've toyed with switching to SSRC.

The counterpoint is that anyone this hardcore about quality would be using a bit-perfect ASIO connection.

Also, that file is a contrived example to show the flaw in one type of resampler, and doesn't really reflect real world results.
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Matt Ashland, JRiver Media Center

thomaspf

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Re:udial.ape uncovers resampler problems!
« Reply #4 on: September 22, 2004, 04:05:40 pm »

Hi Matt,

thanks again for fixing the ASIO driver problems. I indeed use ASIO for bit perfect output to avoid kmixer since that introduces yet another level of distortions.

However, in one of my systems I replaced the S/DIF connection to my trusted Monarchy Audio 22C with a 192Khz capable sound card (ESI Juli@) to play with WMA hires formats.

When I tried to upsample material from my 16/44.1 library I was somewhat underwhelmed which led me to try the udial test track.

I use it regularly on unknown systems to evaluate how clean a playback path they provide and this has worked really well as an indicator for me.

I don't want to get into a debate about how much of a corner case udial really is but adopting ssrc sounds like low hanging fruit.

Cheers

     Thomas
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Matt

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Re:udial.ape uncovers resampler problems!
« Reply #5 on: September 22, 2004, 04:26:34 pm »

Next build of MC 11 will use SSRC for all resampling.
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Matt Ashland, JRiver Media Center

Matt

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Matt Ashland, JRiver Media Center

thomaspf

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Re:udial.ape uncovers resampler problems!
« Reply #7 on: September 22, 2004, 05:06:30 pm »

Wow,

that was prompt. I will play with it and report back.

Thank you so much

     Thomas

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thomaspf

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Re:udial.ape uncovers resampler problems!
« Reply #8 on: September 22, 2004, 05:44:32 pm »

The difference is dramatic on the udial sample track! The new resampler does not introduce any artefacts and the backgrounds stays quiet. Very nice indeed.

Is there also a change in the internal volume algorithm between 10 and 11. On 10 there were some artefacts being introduced but on 11 this seems to be more quiet.

I will go back to upsampling some stuff from my 16/44.1 library to see how that feels now.

btw. I also paid for the upgrade right away.....

I updated the title of the thread to reflect this update.

Thanks

    Thomas
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Matt

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Re:udial.ape uncovers resampler problems!
« Reply #9 on: September 22, 2004, 05:50:40 pm »

All volume handling (and any other audio handling) is done with 32-bit precision in Media Center.  Since the internal volume system uses this same 32-bit precision, it should be essentially perfect.
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Matt Ashland, JRiver Media Center

thomaspf

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Re:udial.ape uncovers resampler problems! solved in 11.0.88!!!
« Reply #10 on: September 22, 2004, 06:07:49 pm »

It seems pretty perfect now.

I guess it was some interaction with the old resampler.

Thomas
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