How Chord M-Scaler works in layman's terms

[castleofargh]

It's admittedly a filter, just not a reconstruction filter. Even if most filters are indeed a mix of digital and analog, here IMO it's a big nothing. It happens before files that aren't going to invent signal above half their sample rate, and after a DAC that will resample however it likes and will cause all the extra signal in need of filtering while making the analog signal.


When it comes to reconstruction filter, M-scaler be like:

 

[FunkyBassMan]

No, that quote is effectively describing a NOS DAC which is not what I'm referring to
Again, digital upsampling IS reconstruction. It's not just adding extra samples for no reason

Exactly.

 

[bigshot]

This is will surprise no one: I'd recommend a good psychiatrist. Your psychoses and hearing may possibly be improvable with medication.

Well! This one doesn't seem to have too much to offer. NEXT!!!

 

[bigshot]

Objectively speaking, to achieve perfect reconstruction we need a perfect filter.

...and to achieve good enough reconstruction, we need a good enough filter. There is such a thing as "good enough".

Reconstruction filters vary from inaudible to inaudible to inaudible to a little bit audible. There are enough good enough ones that it really isn't hard to pick one that is transparent to human ears. You may want perfection from a theoretical standpoint, but as long as your are human and hear like a human hears, you really don't need it.

Sound quality is a good thing to aspire to improving. But the focus should be on things that actually make a significant difference. Reconstruction filters are the way they are because they work. If they didn't work, they would have been fixed by now. High end audio creates components that are like children's busy boxes... you know those toys with a bunch of dials and levers on them that kids can play with? They put "pure audio" bypass switches, they include options of a bunch of reconstruction filters you'd never need in normal use, they jump through hoops to reproduce frequencies human ears can't hear... All in the name of striving for "perfection". But what's the point of perfection if you can't hear it?

I worry about stuff I can hear. There's enough of that to keep me busy. If someone thinks that they've got the main parts of sound reproduction perfect enough that they need to focus on perfecting inaudible sound, they probably don't know jack diddly about optimizing the main parts of sound reproduction. That's a lot harder than it sounds.

 

[GoldenSound]

There is such a thing as "good enough".

There is, but there is not a conclusive answer as to what constitutes 'good enough' yet. And as such the argument that most DAC filters are fine is quite simply an assumption.

Hence the testing.
If you're aware of a thorough and conclusive study on the matter I'd be interested to read it but I'm not aware of any literature that provides this thus far

 

[bigshot]

I didn't 'get all dodgy'. I just pointed out that I'd answered this question to you directly previously and am not really wanting to answer the same questions again and again when I've already given answers.

If I ask a simple yes or no question, all I really need is a yes or a no. Believe it or not, I don't know who you are. You're just a poster on an Internet forum to me. All the posters blend into one in my head. If you posted a bunch of charts and diagrams several months ago, I'm sorry. I don't remember them. If you can't be bothered to just explain what you're talking about in a simple two or three letter sentence, I'm not motivated to spend hours going through archives of your previous posts to find out.

I now know that you aren't comparing DACs, you're comparing reconstruction filters. I have no interest in stuff like that. The reconstruction filters on all of my players are audibly transparent and all of the DACs are audibly transparent. I have even less interest in upsampling. DACs just work. "If it ain't broke, don't fix it."

 

[bigshot]

There is, but there is not a conclusive answer as to what constitutes 'good enough

Of course there is.

Audibility tests have been done for over a hundred years. You set up a simple ABX listening test with a bunch of people and ask them to discern a difference. If they can't, then you know it's good enough.

We can measure stuff we can't hear. If you want to determine JDD, you do a controlled listening test. Measurements may give you some sort of indication about whether you might be able to tell a difference, but just because you measure a difference, it doesn't mean it's audible.

 

[Ryokan]

Is it possible to hear some sound subliminally, Is subliminal priming a thing in audio?

 

[eq1849]

Is it possible to hear some sound subliminally, Is subliminal priming a thing in audio?

There is, but there is not a conclusive answer as to what constitutes 'good enough' yet. And as such the argument that most DAC filters are fine is quite simply an assumption.

Hence the testing.
If you're aware of a thorough and conclusive study on the matter I'd be interested to read it but I'm not aware of any literature that provides this thus far

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5285336/

 

[FunkyBassMan]

Is it possible to hear some sound subliminally, Is subliminal priming a thing in audio?

This is probably the wrong place to get that answer. They can't even hear normally, let alone subliminally.

Though GoldenOne certainly can hear, and may have some helpful info.

 

[castleofargh]

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5285336/

This says nothing about the content. One might argue that a crappy filter could lead to the same results as higher frequency range music. And if they're right that we get a better experience with higher frequencies, then the better filter would somewhat be bad...
It's real easy to spin those stuff whichever way we chose because of how little is actually being tested.

I find this paper very confusing. In part because it's complicated stuff, and I certainly don't know all of it. And in part because of what feels like very strict protocols, leading to big liberties in interpreting results and calling something positive or not. I have a hard time believing the same people were in charge of both.
I read the same thing, and in my head I start wondering if we might behave like ultrasounds are a distraction, as noise. They mention relaxation, that a paper confirmed how people tend to listen louder to hires files.
IDK, They interpret the stuff usually related to the sense of agency in a way that confuses me. I don't know if I'm misunderstanding something or if they again take liberties in interpreting things that they shouldn't?
Interesting read for sure though. Still not really saying anything about DACs and their filters, or how that's audible. But interesting.

 

[VNandor]

Yes, and by that definition the term applies.

It doesn't apply, the wiki clearly states that the reconstruction filter creates an analog signal. The m-scaler at no point creates an analog signal. As a consequence, it needs a DAC to properly reconstruct the analog signal.

You can take the sampled data and use a digital reconstruction filter to provide a reconstructed/smooth waveform vs a sample and hold output.

No, a digital filter outputs a digital signal. A digital signal is discrete in both time and amplitude. This digital signal can be passed to a DAC for reconstructing the analog signal but the m-scaler won't reconstruct the analog signal.

No, that quote is effectively describing a NOS DAC which is not what I'm referring to
Again, digital upsampling IS reconstruction. It's not just adding extra samples for no reason

Saying this again does not make it any more true. Upsampling is not reconstruction. The filter used for upsampling is not a reconstruction filter (as it doesn't reconstruct the analog signal), it's called an interpolation filter (it interpolates samples between already existing ones). The m-scaler has a "high-quality" interpolation filter, not a "HQ" reconstruction filter. If the m-scaler could reconstruct the signal, it wouldn't be used with a DAC, you could just plug it in straight into an amp.

It's important to point out that no matter what, if a DAC has a reconstruction filter (good or bad) the signal will pass through it regardless if an m-scaler is being used before the DAC or not which is certainly not just semantics.

 

[gregorio]

Objectively speaking, to achieve perfect reconstruction we need a perfect filter.

Objectively speaking, we need a filter which exceeds what is objectively audible. Sure, if we were to want perfect reconstruction then we’d obviously need a perfect filter but we don’t need that because we don’t have perfect downstream equipment or ears.

Where the audible limit lies and for what factors (there are multiple issues/factors to different reconstruction approaches and tradeoffs) is up for debate and there is very little study on the matter.

What exactly is up for debate and hasn’t been studied much? Can we hear a filter whose roll-off starts at about 19kHz? Can we hear alias images at -100dB or lower? Can we hear no phase discrepancy? Can we hear filter ringing which occurs rarely in music and is almost all above 20kHz anyway? And countless people in the industry have performed numerous DBTs of filters, I’ve done quite a few myself in the distant past.

Instant meaning that everything below 22.05khz is passed through completely unaltered and everything above that is entirely eliminated. As opposed to partial attenuation or slower rolloffs.

Ah, so you’re talking about a small transition band. What difference does it make if the transition band starts above human hearing or the attenuation is lower than -100dB?

The upsampling IS the reconstruction filter.

No it’s not, it’s output is just another digital signal at a higher sample rate, it’s not reconstructing the original signal.

As to the -80dB claim, that's not true and is unfortunately a result of Amir using less than ideal testing methodology and not setting up the device correctly.

That’s possible, he’s made serious mistakes before and I haven’t looked into this measurement in any depth.

And due to how noise shaper effectiveness is linked to conversion ratio, at 768khz output it's better

And due to that same reason, typical oversampling at far higher rates than 768kHz would be even better.

I'm comparing filters that are higher performance than those inbuilt into most DACs. .. Most DACs use 128-1024 taps which is very low.

No, it’s not “very low”, it’s high performance. Admittedly I have seen some DACs (although not recently) which had fairly dodgy filters, attenuation of only -80dB or so but even that was only just audible and only under quite extreme listening conditions.

G
Edit: Didn’t see VNandor’s post before I posted this. Bit of duplication.

 

[bigshot]

There are two things to test for in listening tests... one is fidelity: does this sound the same as the other sound? The other is preference... does this sound *better* than the other? The former tests what you can physically hear. The latter tests what you prefer. I've never seen any study that indicates that inaudible sound makes any kind of impact on sound quality preferences. In fact, there have been studies that have shown that not only do super audible frequencies not affect sound quality, you can roll off everything above 10kHz and most people will tell you that they have no preference for that as compared to a full range- even though they can hear a difference.

That's an example of sound that you can actually hear that doesn't impact sound quality. There is no "subliminal" hearing. There is just sound that you can hear and sound that you can't.

Super audible frequencies can be perceived if they are loud enough. They can cause headaches, which is why they are often used for crowd control and to keep teenagers from hanging out in parking lots late at night. But that isn't the same as hearing them.

 

[gregorio]

Is it possible to hear some sound subliminally, Is subliminal priming a thing in audio?

Yes, composers have been doing that for centuries, it has to be audible though.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5285336/

Yep, there have been several similar studies over the last 20 years. It’s accepted that ultrasonic content can affect alpha brain waves however the results of this is inconclusive. Some studies indicate a very small positive effect, others indicate a very small negative and some show no effect. However, it’s hard to objectively quantify marginal subjective feelings. Although further research would probably settle the issue, it’s currently fair to conclude there’s probably no effect.

However, all the studies seem to agree the ultrasonic content is inaudible and has no conscious effect.

G