Computer audio- how to get the best sound*

Discussion in 'Audio Hardware' started by jespera, Apr 22, 2018.

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  1. John Dyson

    John Dyson Forum Resident

    Location:
    Fishers, Indiana
    Clearly the answer to that 'sheen' on the sound is (for about 2/3 of the time) DolbyA encoding. I have proof of the DolbyA encoding causing the 'digital' sound in some cases. For example, I don't normally purchase CDs anymore but all two of the CDs that I purchased (Chicago and Queen) both were DolbyA encoded. I have an example of 'Bicycle' from that CD on my repository that I am going to point to below (before and after decoding.) I have several other examples, including from HDtracks -- it isn't their fault, but the suppliers are providing the stuff. My guess is that they never added DolbyA to the chain when using master tapes to produce digital copies. It is a pain in the 'butt' to convert back to analog -- decoded with a DolbyA -- and the re-digitize.

    Historically, people don't have DolbyA units to test with, and it is indeed tim econsuming to run audio through a unit -- so no-one bothers to do it.

    I have written a DolbyA decoder (tested to work very closely to the real thing, but witihout the FET (or diode) distortion and withont some of the intermod that normal HW designs can have.) It is available for free to consumers -- all you gotta do is tell me. The purpose of this response isn't to talk about my decoder specifically.​

    So, what can you do to fix it (without a DolbyA decoder?) A little bit of expansion along with some de-emphasis of the high frequencies will help (I did that in my initial experiments.) I don't know if commercial expanders are fast enough to do a good job -- DolbyA has an almost maximally fast attack/decay characteristic avoiding distortion, so you would need a pretty fast expander.

    DolbyA only has between 10 and 15dB of compression, and it is at levels like -20 to -40 dB, and the curve is for a 30dB range in, there is a 10dB gain change, so it isn't severe, but it is definitely insidious. WITH DOLBYA, IT DOES NOT SOUND AS BAD AS 10-15dB of compression because it is at low levels and tends to make the highs more dense AT THE LOW LEVELS. It has more of a 'feeling' of several dB of real boost, but again -- it is doing A LOT to the low levels. If the signal levels are not low, then DolbyA can sound nearly transparent, but will almost always have that 'sheen'.

    Also, the HF boost is from the odd mix of how the 3k-20k and 9k-20k (or 3k-9k / 9k-20k, depending on where you are looking) will tend to boost the HF.
    The DolbyA NR really works (and even works for room rumble), but isn't capable of as much NR as DolbyC or DolbySR.

    So -- the only thing you can do to be technically correct to get rid of the sheen is to use the Satin DolbyA decoder (doesn't work as well as mine -- has too much upper mid range, they made the same design mistake that I originally did), a real DolbyA (lots of trouble), or my decoder (works on recent PCs, wav to wav, runs approx realtime, 44.1k to 192k, but 88-96k are best.)

    This is the reality -- most people seem not to believe it -- but up until now the answers have been mumbo-jumbo about 'sampling' or EQ or something like that. The EQ thing might sometimes be right (especially special EQ for vinyl), but anytime after the late 1990s, digital effects have NOTHING to do with it.

    As I wrote, abut 2/3s of the time (or more) -- it is DolbyA that hasn't been decoded.

    My site is the following: Hightail Spaces
    The site above has both BEFORE AND AFTER EXAMPLES, all sources (except the ABBA) were from downloads and consumer CDs. The ABBA is some mysterious master tape that I have had for years.

    I am not asking for help/money or anything like that -- I have already gotten LOTS of help from a recording engineer and his 'golden ears' expert on the sound quality. The DolbyA that I am offering is indeed accurate

    John
     
  2. TimB

    TimB Pop, Rock and Blues for me!

    Location:
    Colorado
    Look over at the Schiit site. They have several dac's and stuff to clean up USB ports. While there are many good USB port dac's the big problem is getting a clean signal to them.
     
  3. Welcome Vincent! I always enjoyed your posts on WBF, although I don't really participate there any longer.
    The Well-Tempered Computer
     
    arisinwind likes this.
  4. Ben Toby

    Ben Toby Forum Resident

    Location:
    Western CT

    Hi todddfan, I have the AS701 which has a DAC but not as good as the one in yours. So I put in a Hifiberry DAC+ upstream and love it. You can get a Roon endpoint from them without the DAC (Digi+ I think) for less than $100 and feed that into your 801 and I bet it would sound awesome. i also have a Sonictransporter from Small Green Computer which is a dedicated music computer serving three systems in my home via ethernet. Couldnt be happier with it. Enjoy!!
     
    Rolltide likes this.
  5. Dillydipper

    Dillydipper Space-Age luddite

    Location:
    Central PA
    Vince brings up a good point, or at least sticks his fingers down his throat, but doesn't quite "retch" it out there... :D

    Ten years ago I took some good advice, that inside an electrically/magnetically/interferenc-cy CPU unit, is a lousy place for sound processing. I chose the Echo Gina (and still have it on my main machine!), and immediately benefitted from having the "breakout box", which everything plugs into, outside of the machine itself. In fact, although it could perhaps me removed even further away from the guts, I keep it Velcro'd right underneath the desktop, 6-7" above and away from the CPU.
     
  6. Kal Rubinson

    Kal Rubinson Senior Member

    Location:
    NYC
    Because they are not needed in all situations.
     
  7. Kenneth73

    Kenneth73 Forum Resident

    Location:
    Denmark
    Most important thing to do when building a streamer setup is noise reduction. Fully linear power supply for everything helps a ton.

    Then it's all up to the dac you are using and how you would like to stream to it. Again noise reduction here is very important. Stay away from USB. It has so many negative side effects from USB chips to usb power.

    Streamong via lan or i2s qmd aes is the way to go. Lan has a ton of bandwidth and can be efdeceffe noise isolated.

    I'm streaming with roon via lan. And has a roon endpoint I build myself with transformer couple aes output to my audio Note dac. When streaming to my bricasti I stream directly via lan.
     
  8. jespera

    jespera Well-Known Member Thread Starter

    Location:
    copenhagen
    Im a believer -- though not necessarily an understander.

    Ive just heard Jens Encore's system. Super impressive.

    Maybe theres hope for digital after all :)
     
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