Is DEQX a game changer?

@blang11

We have a couple of other threads re:MQA going on, but yes, it’s true, but ONLY if you are EQ’ing in the digital domain. Using something like a miniDSP or DiracLive which does AD -> EQ -> DA is not affected! Except that if you do that, you are going to do away with the fairy dust MQA sprinkled. More below.

The reason this happens is that the extra octaves are being hidden in the lowest bits of the signal. So, change any of those bits and you ruin the ability to decode the signal. Just like if you took a ZIP file and started messing with the lowest 2 bits of every byte.

Even if you include your DSP in more advanced DAC’s (of which I know of like 2) It’s not at all clear that the alleged benefits of MQA’s digital decoding filters would live through it.  Like doing this in your player:  MQA-> PCM -> EQ -> MQA ouptut filters -> D/A converter

Then you take the reason the filters allegedly work. They claim less time smearing than conventional digital filters. Well, if you stick a miniDSP (or equivalent) your going to be putting your sound through another A/D, D/A signal without any of the fairy dust present.

To my mind this whole house of mirrors starts to unravel when you start asking what happens with multi-track sources, and when the MQA encoding filters gets applied.

By the way, I went to 2L.com and listened to a few MQA encoded tracks. I could not tell a difference between the 96/24 and the MQA which claimed to be doing 384k/24.

From a practical perspective, this whole thing is looking more and more like Enron or "Dark Energy Generators." I’ve yet to either hear a difference, and I have asked, repeatedly, to be given access to a pair of demo tracks which would demonstrate this alleged superiority.

In addition, what I did not know, is that the whole encode/decode system is lossy. Based on the origami charts I had assumed it was lossless. Not so,

Best,


Erik

@blang11

Another thing that is not clear is how MQA encoding plays with regular studio work.

The way it should to work is that the MQA encoding process should take your A/D converers into account and compensate for it’s shortcomings. Well, what does that mean if you are mixing several tracks, or doing level changes, EQ, compression, or expansion? Does MQA somehow magically know how to compensate for these algorithms? Mind you, this is all work done before we even encode the signal. 

It is possible some of this could be overcome, like with DSD. What’s not clear to me is that there’s any benefit at all to MQA encoding. I remain unimpressed.

Best,


Erik

"Roscoeiii: drewan77, Sorry if I missed it, but have you tried DEQX digital out --> external DAC --> preamp (if volume control is needed)? If so, how did that compare to the setup you are currently using ( external DAC =>A/D =>D/A =>out)?"

No I have not - My setup would require at least 3 external DACs & a
multi-channel preamp.

I have no need to change anything except daisy-chain the HDP-3 to the HDP-5 at some future point to add additional mid-bass amps/drivers (for now the HDP-3 is running a system in another room).

From a practical perspective, this whole thing is looking more and more like Enron or "Dark Energy Generators."

"Enron" - I haven't heard that word in a long time..... ;-)

By the way, I think time and frequency correction is very cool. However, there’s a few points I want to make.

Many speakers are just not very neutral in the frequency domain and an EQ is the only way to fix it. From B&W to Martin Logan, some highly touted speakers are not objectively neutral. While we can argue about the overall importance of frequency response, it’s usually the thing people hear first and most. So, the good news is modern EQ can correct this, the bad news is it may leave your speakers sounding like something else.

Second, speaker designers know how to do time and phase matching, it’s just not worth it for many of us. If it were all that, we’d hear about Thiel and Vandersteen exclusively, and no other brands would dare compete. However it’s not the case. There are also some negatives. The hardest part about doing time/phase alignment is actually finding drivers that will let you. You need particularly well behaved drivers, AND you’ll possibly give up significant amounts of dynamic range for it since you may be limited to using first order networks.

Could I design a time/phase coherent speaker? Sure. Would I? Meh. Honestly the Thiel and Vandersteens I’ve heard didn’t do it for me enough that I gave up all other designs. Still, the idea that I can just get a DiracLive or DEQX to fix that all up for me is intriguing!

The one thing to remember too is EQ by itself is not nearly as good as with a balanced, low compression, low distortion speaker with good room treatment.

As with all things, please make yourself happy! :) This is just my own impressions and experience, which doesn’t matter a bit when you shell out your hard earned cash.

Best,

Erik