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Author Topic: Questions about Bit Perfect playback in MC13  (Read 2534 times)

Vocalpoint

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Questions about Bit Perfect playback in MC13
« on: May 23, 2009, 09:38:24 am »

Morning,

Now that the testing is over and I have purchased MC13 (Yay!) - I have questions on "bit perfect" playback. In addition to a few workstations scattered around the house that use consumer level sound cards and basic computer speakers - I really bought MC to enable audiophile playback in my studio environment.

In the studio, I use MC13 to play my FLAC audio exclusively (audio files are on a Windows Home Server share) on a custom built Windows Vista 64 PC sending a digital stream via ASIO from an M-Audio Delta 1010 (SPDIF) out to my new Music Hall DAC25.2.

The sound is spectacular but I want to make sure I am not compromising bit perfect playback by enabling (or not enabling) certain elements within MC13.

First up - the different Volume options (the slider in the upper left). So - I have scoured the online help but still don't have a clear understanding on what these modes are and how they effect (or do not effect) playback or make any difference to bit-perfect playback.

Can anyone set me straight on Application Volume, Internal Volume and System Volume? I have read on a few other audiophile forums that setting the volume slider at any value (in MC and other playback sofware like Foobar) less than 100% could/can result in non-bitperfect playback? Any truth to that?

Secondly - DSP within MC13 while playback is occurring. If I decide to engage the EQ or the Volume Leveling options during playback in MC13 via ASIO - is the stream still bit perfect?

Currently - I am using the Application Volume setting. It's set to around 80% - I chose it because with any of the other modes - the music is very loud and the app volume slider has no effect - and neither does any DSP - so the music is coming on much too strong - especially whe switching between al.

Appreciate any input - especially from those using MC13 with an ASIO-based setup.

Cheers!

VP
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nuvira

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Re: Questions about Bit Perfect playback in MC13
« Reply #1 on: May 23, 2009, 11:10:43 am »

with my research and I found:

1. ASIO is bit-perfect
2. WASAPI is bit-prefect but some MS layer behind, but bit-perfect - my guess
3. I wouldn't touch volume at "SOUND" windows - 100% all the time
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Johnny B

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Re: Questions about Bit Perfect playback in MC13
« Reply #2 on: May 23, 2009, 11:18:20 am »

WASAPI "Exclusive mode" is indeed bit perfect - the problem is that MC13's implementation is not flawless yet; this hopefully will change soon and the guys will repair it.
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)p(

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Re: Questions about Bit Perfect playback in MC13
« Reply #3 on: May 23, 2009, 12:06:23 pm »

WASAPI "Exclusive mode" is indeed bit perfect - the problem is that MC13's implementation is not flawless yet; this hopefully will change soon and the guys will repair it.

What flaws? I switched back to asio because I could hear some weird small cracks...not skipping...never heard them before. Also occasionally it seemed to loose bitrate sync and I got mickey mouse like accelerated sound  ;D But that was in the early builds with wasapi. I was planning to give it another chance soon...so I am interested to know what if any current flaws I have to look for.

peter
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Johnny B

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Re: Questions about Bit Perfect playback in MC13
« Reply #4 on: May 23, 2009, 01:25:52 pm »

Just take a deeper look here in the forum and you would find it yourself...

HINT: thread "Wasapi Exclusive mode Sample Rate Max - Lower Than My Hardware Limits"
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Frobozz

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Re: Questions about Bit Perfect playback in MC13
« Reply #5 on: May 23, 2009, 05:43:39 pm »

WASAPI "Exclusive mode" is indeed bit perfect - the problem is that MC13's implementation is not flawless yet; this hopefully will change soon and the guys will repair it.

The behavior of ASIO and WASAPI are dependent on the drivers used.  Driver issues are beyond MCs control unless the devs are able to work around particular buggy driver behaviors.

WASAPI works fine for me.  I'm using an M-Audio FW410.  M-Audio supplies both an ASIO driver and a standard Windows driver that supports WASAPI.  Both ASIO and WASAPI work fine for me.  Buffering behavior is different in both.  The ASIO driver seems to handle higher latency without glitches better than WASAPI in my setup.  But other than that, both ASIO and WASAPI in MC13 work well and do what they are supposed to do.

It is also worth remembering that ASIO and WASAPI are intended for professional recording situations where low latency is necessary (when monitoring or playing over a prerecorded track you don't want a noticeable delay between what you hear and what is recorded).  ASIO and WASAPI aren't intended to be optimal for general consumer playback.  It just happens that ASIO and WASAPI bypass the Windows mixer and other shenanigans which happens to be beneficial for audiophiles desiring the highest potential quality audio playback.  But that also means dealing with the quirks of an interface designed for professional recording use.
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Frobozz

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Re: Questions about Bit Perfect playback in MC13
« Reply #6 on: May 23, 2009, 06:03:44 pm »

Secondly - DSP within MC13 while playback is occurring. If I decide to engage the EQ or the Volume Leveling options during playback in MC13 via ASIO - is the stream still bit perfect?

ASIO and WASAPI only give you the potential for bitperfect playback.  They do not guarantee bitperfect playback.  Any fiddling of the bits by a digital volume control or an EQ or DSP in MC will no longer have bitperfect playback.

But keep in mind the real goal.  Most people are using bitperfect playback methods to bypass the Windows audio mixer and the other audio fiddling that Windows does to the signal.  The goal is to bypass the Windows audio mixer.  Not everybody actually needs (or wants) true bitperfect playback.  Some people actually want some digital EQ or other digital processing in the signal chain.

The math done by MC for volume control and DSP processing is of high quality.  Digital processing of the signal is not a bad thing if the results of that digital processing is beneficial to you even though you lose the true bitperfect output.

What are you sending the signal from the Music Hall DAC to?  Is there a reason whey the signal is too loud from the DAC and why you can't control the volume after the DAC?  The Music Hall DAC looks like it supports both balanced and unbalanced output.  Are you using the balanced or the unbalanced output?  Is the device that you are sending the signal to (from the DAC) set to the correct line level (unbalanced is typically -10dB and balanced is typically +4dB)?
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Vocalpoint

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Re: Questions about Bit Perfect playback in MC13
« Reply #7 on: May 24, 2009, 11:07:05 am »

Any fiddling of the bits by a digital volume control or an EQ or DSP in MC will no longer have bitperfect playback.

That's what I thought.


The goal is to bypass the Windows audio mixer. 

That's my goal too - but I was hoping for an untapped stream via MC13.

The math done by MC for volume control and DSP processing is of high quality.  Digital processing of the signal is not a bad thing if the results of that digital processing is beneficial to you even though you lose the true bitperfect output.

Yes - it does sound great and for my usage - the processing is not having a detrimental effect.

What are you sending the signal from the Music Hall DAC to?  Is there a reason whey the signal is too loud from the DAC and why you can't control the volume after the DAC?  The Music Hall DAC looks like it supports both balanced and unbalanced output.  Are you using the balanced or the unbalanced output?  Is the device that you are sending the signal to (from the DAC) set to the correct line level (unbalanced is typically -10dB and balanced is typically +4dB)?

From the Music Hall - I go "unbalanced" to my Rega Mira 3 amp and out to my Monitor Audio RS6 floorstanders.

Regarding the loudness - I wanted to know the impact of DSP (Volume Levelling specifically) and how it impacts bit perfect playback via MC.

Of course I have full control over the volume via the Mira remote - but the "loudness" issue arises if I want to listen to a playlist or specific selected tracks via MC13 and stay completely "bit perfect" (aka -  without any Volume Levelling inline)

Example - a 2009 mastered track like say - the excellent new Ben Harper - comes thundering out of the speakers whilst the next track from Counting Crows circa 1993 is about 6db lower. So - if bit perfect playback is the goal then no DSP is allowed - and a guy is constantly reaching for the remote to either lower or raise the volume so the playlist has a reasonable volume range.

I guess I will have to accept a non bit perfect stream in order to have MC13 apply it's volume leveling - because the excellent playlist capabilities are too good to past up just to get bit perfect playback.

Thanks!

VP
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