XXHighEnd

Ultimate Audio Playback => Download Area and Release Notes => Topic started by: PeterSt on April 13, 2008, 10:09:15 pm



Title: XXHighEnd Model 0.9u-14 (with AA filter for up- and downsampling)
Post by: PeterSt on April 13, 2008, 10:09:15 pm
It is strongly advised to not use your system without a preamp (or the pre-amp at max volume for that matter) if you or your speakers won't be able to handle a situation that e.g. the file contains wrongly formatted data or otherwise - because of which cracks may emerge with an energy beyond imagination.

The following changes have been applied (Engine#3 unless otherwise noted) :

  • Upsampling (Double and Quad) now allows for an Anti Alias filter, which is applied when the new AA checkbox is ticked.

    You can try this when the lack of the AA filter bothers you, from theory or practice.
    Keep in mind though that the preprocessing needed for this takes some 30 seconds for 5 minutes of playback, which implies that with Attended playback it cannot be used when gapless is required. Also, with Unattened it takes just that time to prepare the tracks for playing.
    Note that just Double or Quad doesn't allow the AA filter to be applied. Only Upsampling does that.
    Theoretically this applies to all Engines, but only Engine#3 has been tested.

    The AA filter obviously does not lead to bit perfect playback (as Upsampling already would not).

  • The Anti Alias filter actually was born within XXHighEnd to support for DXD (352800) downsampling to 176400, which was introduced by 0.9u-12, including lots of noise because just the lack of the AA filter.
    Keep in mind that DXD 352800 playback needs the Mem checkbox to be ticked.
    Together with this subsequent playback of DXD files downsampled to 176400 now works (previous versions let error XXEngine3 at the end of the track).
    Native 352800 files (for the rare who have a DAC to play that back) will still error at the end when more tracks are asked for playback.
    Note regarding the title and downsampling : Only downsampling from 352800 to 176400 is supported. This does not require to tick the AA checkbox, and goes by automation; But might you have a DAC that supports 352800, downsampling is not applied.

  • With special thanks to Gerard, during the load of a next track the Q1 setting is set to 14. After that next track commences playing it is reset to you original setting.
    Tests show that this helps eliminating the hiccups as have been reported since more preprocessing is applied (hence with the Mem checkbox not ticked), but with again larger files to be loaded because of the applied AA filter as mentioned above, it still can happen. Please report if this is so at one occasion per album at least. It should be rare and merely one occasion per day.

  • A bug has been found on 176400/24 playback with a 16 bit DAC. This has been solved, but note this has not been tested.

  • At the preprocessing needed for FLAC and MP3, the time position cursor commenced before meant preprocessing was finished. This has been solved now. Theoretically this invloves Engine#1 just the same, but nothing has been changed here.

  • The choice for the Engine has been moved to the Settings Area in order to create some space in the left pane.

  • A bug has been found for the Q1 settings of -2 and -3;
    -2 appeared to be set equal to -1;
    -3 appeared to be set equal to -4.
    Now both have their own values indeed.


Additional notes on the AA filter application :

Since this is preprocessed out of XXEngine3, no additional (hence anomalies) on SQ are to be expected from withing XXEngine3 itself. But :
It appears that applying the AA filter, incurs for heavy I/O for over 10 seconds just *after* the track has been preprocessed and is already playing. Theoretically, during this time, SQ may be influenced because of this.
The additional I/O you see is outside of the control of XX, and seems to be the flushing of the paging file (swap file), related to the heavy I/O needed to apply the AA filter, as occurred before even a first tone from playback was heard (we're talking UnAttended here).

Furthermore, it certainly seems worth while investigating the SQ of Upsampling by this means (the AA filter) and overall it may be better than normal playback. It certainly does not seem annoying, unveils more from the tracks (mainly in the voice area ?), and only at rare occasions high frequency anomalies emerge.
Please let know what you think ...

Lastly, this is the time to check the 2 channel DXD 352800/24 files from http://www.2l.no/hires/index.html but keep in mind that you will only be able to play them by means of 176400/24 downsampling (if all is right 176400/16 for those with a DAC at that rate but 16 bits only will work too). Unless you have that 352800 DAC of course, then it plays 1:1. In either case, do not forget to tick the Mem checkbox.

Edit : It has been reported that those running with a Q1 higher than 14 have problems at track boundaries (XXEngine3 stopped working).
Edit 2 : This has been solved in 0.9u-14a.