Home
AudioAsylum Trader
Critic's Corner

Discuss a review. Provide constructive feedback. Talk to the industry.

For Sale Ads

FAQ / News / Events

 

Use this form to submit comments directly to the Asylum moderators for this forum. We're particularly interested in truly outstanding posts that might be added to our FAQs.

You may also use this form to provide feedback or to call attention to messages that may be in violation of our content rules.

You must login to use this feature.

Inmate Login


Login to access features only available to registered Asylum Inmates.
    By default, logging in will set a session cookie that disappears when you close your browser. Clicking on the 'Remember my Moniker & Password' below will cause a permanent 'Login Cookie' to be set.

Moniker/Username:

The Name that you picked or by default, your email.
Forgot Moniker?

 
 

Examples "Rapper", "Bob W", "joe@aol.com".

Password:    

Forgot Password?

 Remember my Moniker & Password ( What's this?)

If you don't have an Asylum Account, you can create one by clicking Here.

Our privacy policy can be reviewed by clicking Here.

Inmate Comments

From:  
Your Email:  
Subject:  

Message Comments

   

Original Message

On the blurriness of MQA

Posted by Dave_K on November 2, 2016 at 12:38:32:

Something occurred to me as I skimmed the arguments below.

I think it would be more technically accurate to call Meridian's proposed ideal system impulse response a blurring filter. It has a slow roll-off response and its shape is designed to be as close as possible to a Gaussian. In image processing, Gaussian filtering is also called Gaussian blur. It is used to soften and smooth images.

In their 2014 AES paper, Stuart and Craven say that their ideal system response is equivalent to the dispersion of sound passing through 10m of air. They speak of it like it's a good thing. But how about zero meters? Why should we accept a system that adds any dispersion at all? Conventional high sample rate PCM systems (I would say 88.2k and above, but it depends on the source of music) can already pass the full musical spectrum without adding any dispersion. Compared to that, Stuart's system adds temporal dispersion and high frequency roll-off, smoothing over transients somewhat. I know it's "only" equivalent to 10m of air, which seems like it should be pretty benign, but why adopt a system whose design target is less transparent than what's already available?

Second, the idea of selecting a reconstruction filter on playback that's matched to the anti-aliasing filter used in recording was a fine idea when it was implemented for HDCD because of the limitations of the Redbook format, where both filters had to be right at the top of the audible band. It is completely unnecessary at higher sample rates where the filters' stop bands begin at a frequency higher than the musical content.