[514077]

I have talked about this many times before; before pulse array I used PDM 256, which is identical to DSD 256, which is the same as you suggest; but DSD suffers from immense technical flaws that can't be solved, and never can be solved. This was what lead me to develop pulse array way back in 1995. To summarise these problems are:

3. Poor signal resolution. The limited truncation output (+1 or -1) and noise shaper rate (256FS) means that small signal resolution is much poorer than pulse array; you need 350 dB performance to maintain depth perception, and DSD is incapable of anything like this performance; DSD64 is only capable of 120 dB noise shaper performance. This is responsible for DSD lacking depth and sounding flat.

We can see these problems in practical measurements; that is why I am so keen on publishing measurements, as this proves that pulse array does not suffer from these serious drawbacks that create large measurable problems, and IMHO huge SQ issues.

Sorry Rob, but I'm asking from one of your older posts, from a recent link. Referring to your #3 point above, and bare in mind, I'm a simple man: Does that mean that DSD may have been somewhat useful as an improvement over CDs until pulse array was invented? i.e. 120db vs 350db. I've been thinking that DSD might at one time, have been an uptake, to be superseded by higher bit depth PCM. Am I anywhere in the ballpark?

 

[Rob Watts]

Sure; I used PDM (PDM is the same as DSD - it was DSD256) DACs before pulse array; indeed I invented pulse array in order to solve the SQ and measurement issues that DSD had. In the early 90s I was using multiple randomised noise shapers, and 32 element DSD conversion to analogue. In spite of this sophistication, the system was severely limited in performance and with resolution, which of course pulse array solved. Remember that the small signal linearity of PDM or DSD is much better than can be achieved via R2R DACs - and this push for better noise shaper performance is all about ensuring that small signals are more accurately reproduced.

Moreover, DSD has other problems that can't be fixed; noise floor modulation from the modulators, as increasing levels changes the integrators behaviour; timing issues, in that the delay of the output is amplitude dependent - so we see small transients having a longer delay than large transients. This I feel is the reason why DSD sounds unnaturally soft, as transients are not reproduced accurately enough.

 

[Peter Hyatt]

Rob, did you see this?

https://www.dailymail.co.uk/sciencetech/article-6757683/Inside-quietest-room-world.html

 

[Rob Watts]

Not really any different to the thousands of other anechoic chambers in the world - and entering into one makes one feel discombobulated. And I am not sure that the feeling is down to the silence; after all, hiking in the mountains on a perfectly still day is silence - but you feel fine. I wonder if it's because the brain builds up a sonic footprint of the environment you are in - so that it can compute soundstage and timbre - and perhaps that disconcerting feeling is simply the brain having a null result for the environment acoustic footprint - something which you never experience naturally.

Just a thought on my part...

 

[JaZZ]

My take on it: What makes it so discombobulating is the frequency imbalance of the residual reflected sound waves. It's impossible to completely absorb the lowest frequencies. So an anechoic chamber represents an acoustically unnatural environment.

 

[jlbrach]

in such intense silence one would hear their heart beating and the internal workings of the body and could literally go mad

 

[JaZZ]

in such intense silence one would hear their heart beating and the internal workings of the body and could literally go mad

That's nothing extraordinary for IEM users.

 

[jlbrach]

i too have used IEM's like the etomytic 4 which do a very good job of isolation but even that is nothing like total and complete silence

 

[JaZZ]

Like Rob Watts I have found silence to be highly impressive on a high Swiss mountain, but it wasn't disturbing in the least. – Sadly with my now tinnitus I can't repeat this experience.

 

[iDesign]

Not really any different to the thousands of other anechoic chambers in the world - and entering into one makes one feel discombobulated. And I am not sure that the feeling is down to the silence; after all, hiking in the mountains on a perfectly still day is silence - but you feel fine. I wonder if it's because the brain builds up a sonic footprint of the environment you are in - so that it can compute soundstage and timbre - and perhaps that disconcerting feeling is simply the brain having a null result for the environment acoustic footprint - something which you never experience naturally.

Just a thought on my part...

Then one ponders how the phenomena described in the article relates to persons with Profound Hearing Loss (defined as 90 dB+ HL or greater) and their fascinating ability to adapt.

 

[jarnopp]

Then one ponders how the phenomena described in the article relates to persons with Profound Hearing Loss (defined as 90 dB+ HL or greater) and their fascinating ability to adapt.

Vibration? An anechoic chamber would also damp reflected vibrations, I assume.

 

[jagwap]

I didn't get to try it, but I spoke to the guy that manages some of the rooms on this site, and while admittedly very quite, he is not convinced it is necessarily the quietest in the world, as it used a novel B&K measurement technique to prove it. Others may not have access to the technique so will not measure as well, but actually be quieter. He is a practical man.

 

[Pokemonn]

Complete silence is impossible in a normal home environment for now. you can very easily measure your room noise with simple iPhone + SPL FFT apps. You can easily find a huge noise in your rooms.
You can search the sound isolation ability(dB) of normal windows/walls(even concrete made) etc. They are surprisingly very very poor. its one of the reason why you(and me lol) and good kind people still need headphones(in some case, closed back.). Your room noise didn't exist in original recordings which have original natural noise in most case.
If human technology archived complete silence, then probably natural noise generators will be available at the cheapest cost. IMO. so it's not a big issue at all.
Sony has already created Vinyl Processor Technology. Noise generator-like technology has already does exist even for now.

 

[DaveRedRef-III]

Rob
Given that we have a long standing protocol for sending digital audio signals in analogue rather than 0’s and 1’s packages (as with all other digital data) and this protocol is so distorted by negative influences affecting sound quality along the way, why do you think the the industry has not adopted the latter solution, opting for conversion of 0’s and 1’s at the point where you are ready for a transducer to send the sound through air?

I am sure you are more aware than most Rob of the myriad of negative influences on the signal along the way. It must be the bane of your life! Even the negative influence of a spinning disc for data retrieval for instance will take its toll on SQ. We can of course improve things by reading from a Solid state disc but this is only the tip of the iceberg of negative influences along the way.

I am half assuming my suggestion is missing something obvious because it makes no sense to me that the industry is still ploughing this same furrow.

Expecting a Homer Simpson moment any time now! Doh

 

[Triode User]

Are not all and every digital signals just analogue square wave forms? And I thought that contrary to what you say the music digital signals are in reality very robust and the music itself in the digital signal survives all manner of attacks completely unaltered (I can’t remember when I last has a click or pop signalling a corrupt digital part signal).

The damage is rather the noise overlaid on the digital signal carrier which can get into the analogue stages of DACs and other equipment causing intermodulation distortion.

Like you though, I’m happy to be told I don’t know what I’m talking about!