Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion HiFi & HT Chat Apodizing filter fixes one problem and creates another one?

I've been digging around to better understand DACs and filters and ran into some very interesting articles.

One thing that prompted me was in reading some reviews that some DACs give users a choice of filters because there are tradeoffs to each. What's interesting is Apodizing was a choice and not the one the reviewer preferred.

I always found it odd that you didn't have a choice on Meridian and is only ever used when upsampling.

This first article is rather disturbing because the Apodizing filter adds phase shifts relative to frequency. There is no free lunch. It adds phase errors on the same scale that MQA claims to fix. It references this forum and I apologize if this has been hashed out in some now closed heated debate or something. But that article was well before MQA which talks about fixing subtle phase errors which Apodizing ADDs.

Mr Apodizer Blog on issues with Apodizing filter

So how accurate is the claim above? Well here is an excellent paper for understanding the math behind these filters and does backup (IMHO) the above claim. This is an excellent paper.

Larvy Engineering Paper on FIR filters

This is Rob Watts explanation of things and is consistent with both articles above.
Upsampling always bothered me. The goal is to "up sample" to infinity (i.e. Analog).
Which is how he looks at it. By adding more and more taps he is effectively upsampling towards infinity and why he claims the more taps the better.

Rob Watts interview on his filter

I really don't care about who buys what at what price. I want to understand the science behind any of it. And know who to listen to. It's hard to know.

But I know where the science is leading me, to my current understanding.

I don't blindly follow $$$ or pounds.

I'm sorry that you find some of these articles disturbing. Thankfully, these technologies and articles have been discussed to death yonks ago, and most people have come to their own conclusions and rest soundly in the knowledge that they get great enjoyment out of the choices that they have made.

But if you do want to spoil it for those that have blindly followed others, how exactly do these artefacts that apodizing has caused affect the music that we are all trying to enjoy so we can all keep an ear out when we hear them and have our day ruined by the turmoil caused by not knowing if what we are listening to is technically right or not.

Curious if you have links to those discussions, as I did look for them.

Also few things are fairly recent.

1) Some of the argument in favor of apodizing was that the small timing errors were not perceived by human ears (back then). But now MQA's (new) claim to fame is fixing small timing errors that the human ear is incredible good at perceiving (which Rob Watt's agrees with that human can perceive small timing errors).

2) Some recent DAC's (new) that allow you to choose the filter. So you can now A/B without involving other differences in equipment. But none have the choice of the Rob Watts filter. It's Rob Watts or nothing.

3) The Rob Watt's take on things, which is fairly recent (last 3 years-ish, i.e. new) and won't be happy until he reaches 1 million taps. He's up to 150K in his top end DAC. His take is basically building a better symmetric filter with no phase problems. Which takes a lot of horse power.

4) The "recent" review of Meridian Prime shows HUGE Jitter (measured timing errors) (new). And Rob Watt's designs show incredibly low Jitter (the measurements jive with what he says he does). But Meridian's don't. I also find it a bit odd that Stereophile skipped jitter test on Explorer 2. Yet they consistently do that test on all DAC reviews.

Rob watts very recently references MQA here (new), and this guy really doesn't seem to be on the attack or a Marketing guru. He really feels like an engineer just stating the way HE SEES things, not to attack others. And his arguments are very consistent with the Larvy document I posted above (from nearly 20 years ago).

Rob Watts recent comments on MQA

I dug deep nearly 20 years ago on what Meridian did vs others and they technically convinced me they had things right. And most of my investment has been around Home Theater. And I started this site at that point. I was well invested in other brands at that point. My ears confirmed what they technically said they did.

With a headphone setup, I wasn't linked to any current investment, and I certainly would allow Meridian to compete and tried both Explorer 2 and Prime. But I tried several others and Meridian came up short (very short if you factor in price). I want to understand why technically what is behind what my ears are telling me. Not my wallet or brand loyalty.

What is technically going on?

The Larvy document convinced me Rob Watt's is right and Meridian (isn't necessarily wrong) but is very contradicting and very difficult to prove technically the way they package it if they are technically correct.

Meridian has no issue if the equivalent of Audiophile fists fights break out in the process among their own customers. But Rob Watt's is completely open about everything and you can directly ask him just about anything and his answers make sense. As much sense as Meridian's paper on DSP Speakers did years ago. No Origami.

I let my ears confirm what technically makes sense. Because your ears can be trained into liking almost anything if that's all you listen to.

Maybe this site is too biased and brand loyal to have a open frank technical discussion on what makes quality audio. Today.

I put "new" in places that contradict "yonks ago".

It is a Meridian user support site in case you had forgotten.

ncpl,

I didn't realize current advances, technologies, methods, priorities by other smart people in the industry that might differ with Meridian's were not to be discussed or questioned here?

I am not in a position to argue the technicalities but I do like what I hear in my humble real world system.
I expect all appodising is not he same and am certain Meridian did a lot of research and listening before they released their preferred rendition.
There was a great program recently about the senses on BBC Radio 4
In the one about hearing there is a beautiful experiment where they play some distorted sound, so distorted that it's beyond and possibility of recognition. It's noise really. Then they played a transcript of the verbal content. After that when the distorted sound was replayed you could easily discern what was previously noise.

Not sure what this means here but it displays the power of the brain and the importance of taking this into account.
It also de values A/B testing at a stroke.

The predictive power of the Brain

Chris

Isn't this forum to discuss non Meridian Hi-Fi and chat?

That program sounds great, I'd love to hear it but I can't get here.
There are few good shows here too, that have had shows on the topic of Music, Human hearing etc. Like Radio Lab.

I totally agree you, you have to be very careful with how A/B testing is conducted.
You can normalize out "conditioning".

There was a similar discussion on another audio forum talking about a test making this conditioning effect more obvious.

Put one hand in a cold bucket of water, the other in a hot bucket for 1 minute or so.
Now move the hand from the cold bucket to hot bucket.

Do both hands sense the same temperature?

Of course not because they have been conditioned.

Oh wait, your link worked !! I've tried before and could not. Thanks.

Here is a very interesting case of "Conditioning".

Rite of Spring Radio Lab

Indeed. That is why I moved it here.

Great, we're all set then.

Thanks for moving it and supporting the forum.

I didn't want to detract the other thread on HiResAudio Abadoning MQA nor create a new thread that is taken negatively.

But to me there is a large blur between Apodizing and MQA

This very article is very enlightening.

It is balanced and honest people truly trying to understand things that they are, like myself very skeptical about.

We can't seem to have those sort of technical discussions here though but to do happen elsewhere.

These two posts are exactly how I feel about MQA as do many folks.
And they are NOT totally negative.

Archimago Blog on Comparison of MQA

Archimago Blog on MQA vs old Apodizing Filter

Archimago Blog on examining Tidal MQA

We get it... for whatever reason, you don't like or understand MQA and the potential benefits it can possibly bring to music listening enjoyment

But if you're going to look for authoritative backup, you can surely find someone with more Bona Fides, technical merit and basic honesty on their motivations than Archimago??

Is it any wonder that none of his blog postings are ever submitted for Peer Review... as neither his statements or measurement come remotely close to meeting the demands of that discipline... and this applies to all his postings, not just those on MQA

If I were choosing to embark on an anti-MQA crusade, then I would want a far more reliable bed-fellow than Archimago