PGGB questions, answered.

What is new in V9?

V9 detailed guide & upgrades ↗

V9 is the biggest change to PGGB since it started. Until now PGGB remastered your music to a file and your player took it from there. V9 keeps all of that, and adds a way to hear the same processing while you listen. It also replaces the engine underneath with one that asks far less of your computer.

V9 beta: The Live Edition.

You can grab it here: Download PGGB V9. V9 beta. The release date will be announced.

Every V8 license works in V9 as it is. The upgrade is free and there is nothing to request. V9 installs alongside V8, as a separate program on Windows and a separate app bundle on the Mac, and your settings carry over.

Precision Optimized Upsampling Engine.

Introduced in V9, the default engine is an efficient reformulation of the Nyquist-Shannon upsampling engine. It is a true breakthrough in both upsampling quality and processing speed. It builds a processing pipeline tailored to the selected precision and the input and output sample rates. Within the passband (the frequency range it preserves), reconstruction accuracy is limited by the selected precision. It uses much less RAM and is considerably faster than the legacy engine. Listeners describe more natural timbre, clearer instrumental separation and a deeper sense of space. Read about the PGGB engine ↗

What it means in practice is that PGGB stopped being a memory problem. The old engine held the whole track in memory at working precision, which is why long tracks and high DSD rates needed so much RAM or paging space. The new engine does not, so memory use no longer grows with the length of a track, paging is rarely needed, and how fast PGGB runs comes down to how many cores your processor has. For Offline PCM up to 256-bit precision and DSD up to DSD256, start with a 4-core processor and 16 GB RAM. For DSD512, we recommend at least an 8-core processor and 24 GB RAM. DSD1024 and DSD2048 benefit from more cores and 32–64 GB RAM.

Open Settings → Processing to choose the engine. Precision optimized is selected when you install PGGB. Select Legacy to use the old engine, which still works as it did. Memory and Paging is under Legacy; those settings do not apply to Precision optimized.

With Precision optimized selected, choose Optimal, Alternate or Minimal. Optimal is the default and the recommended starting point. Alternate keeps a slightly wider frequency range before rolling off. Both match reconstruction accuracy to PGGB’s internal calculation precision within the frequency range they preserve. Minimal applies the least high-frequency filtering and may allow more high-frequency distortion. Compare on familiar music and choose what you prefer; a wider bandwidth is not necessarily better.

PGGB-Live (beta)

PGGB-Live does the upsampling or downsampling while you listen and sends it straight to your DAC, or over the network to a renderer. You can play your own files, or leave the player you already use in charge and let it play into PGGB through a sound device V9 installs called the PGGB Bridge. PGGB also shows up as a UPnP renderer, so a control point can send music to it.

For a local DAC, output is WASAPI or ASIO on Windows and Core Audio on Mac. For network output, use PAL when available, with UPnP as the fallback. DSD is sent as Native or DoP where the endpoint supports it. The four output modes are Bypass, Bypass with level, PCM and DSD. With DSD output, a new setting starts playing while PGGB measures it during the first minutes of playback. The same applies to PCM on the Precision Optimized Engine at 107, 128 or 256 Bit and 176.4 kHz or higher, with Dither Only off. On the first play of an unmeasured setting, the measured speed can take a few minutes to appear on the strip. If you stop before it appears, PGGB saves any result it already has. If there is no result yet, the next Play measures the setting again. Device Input still measures before playback. Other PCM settings start from an estimate when one is available; otherwise PGGB measures before the music starts. Use Calibrate for a measured result.

It is marked beta because real-time processing depends far more on your particular machine than offline processing ever did. The PGGB-Live guide covers all of it.

PGGB-Remote.

PGGB puts a small web page on your home network so you can run it from wherever you listen. There is nothing to install on the phone. Open the address in a browser, and if you use it often, add it to your home screen. You get now playing with artwork, transport and volume, your music folders to browse and queue from, and the configuration sheet.

PGGB-ARC.

PGGB-ARC (Anthropometric Room and Crossfeed) makes music easier to listen to on headphones, and it works with both PCM and DSD. Music is mixed on loudspeakers, where each ear hears a little of both. Headphones do not work that way, so the music ends up feeling like it is inside your head. Crossfeed softens that, and an optional room puts the music in a space instead of in a vacuum.

For DSD source files, ARC requires the Precision optimized engine. PCM source files support ARC with either engine.

You can set your own head measurements, the speaker angle, and brightness compensation, and pick a room from Studio, Living Room or Concert Hall. The room part is offline only. Crossfeed also applies to live playback. This is not a speaker simulator and the goal is a modest one. The PGGB-ARC guide goes through every control.

Licensing Is Now Self-Service.

This is the change I should have made years ago. Your email address and an activation code are all you need. There is no Hardware ID to look up and no license file to install. Moving to a new computer is something you now do yourself: install PGGB, enter your email and code, and the old computer switches to Lite the next time it starts. You do not need to email me, and you do not need to turn the old machine on.

Computers that cannot reach the license service are still covered by a license file, and that path has not changed. See Activating your license.

A Live License With Pro and Max.

Pro and Max now each include a second license at no cost, a Live license at the same level. It covers PGGB-Live only, with no offline processing, so you can put it on the machine connected to your system and keep the full license on the machine you remaster with. It cannot be bought on its own and there is nothing to pay or request.

Release Notes.

Version V9 beta: The Live Edition (PGGB Plus)

• SQ Changes: the Precision Optimized Upsampling Engine is the new default, and listeners have reported the best subjective quality with it
• Features:
  • New Precision Optimized Upsampling Engine, on by default, with far lower memory use and speed tied to processor cores rather than paging
  • Filter Choice: Optimal (default), Alternate and Minimal
  • PGGB-Live real-time playback to a DAC or a network renderer (beta)
  • PGGB Bridge, a sound device that lets any player feed PGGB
  • UPnP renderer support, in and out
  • PGGB-Remote phone and tablet control over your network
  • PGGB-ARC crossfeed, anthropometry and room, for PCM and DSD
  • Self-service licensing with an email address and activation code, including moving a license to another computer
  • A Live license included with Pro and Max

Upgrades from V8.

There are none to buy. Every V8 license activates V9 at the same tier. The first time V9 starts with an internet connection it registers your license to the email it was issued to, and from then on the Register button under Settings → Application → License and About reads Activation Code and shows your code whenever you need it.

If you are new to PGGB, there is still a free 30-day trial that converts to a perpetual Lite license. The tiers are laid out on the product page.

As always, I am looking forward to your feedback, particularly on the new engine and on PGGB-Live across different machines and DACs.

What is new in V9, compared with V7.

The prose above covers what V9 adds to V8. If you are coming from V7 or earlier, this table is the fuller picture, since it also carries the speed and modulator work that arrived in V8.

Comparing V9 Tiers.

* If no major updates within first year, free upgrade until next major version.
† Anything inside your tier's range, shown above, streams with no time limit. You can play something above your range as well, but only for 30 minutes each time you run PGGB. That half hour counts playing time, so pausing does not use it up, and tracks inside your range never draw on it. When it runs out the stream stops and PGGB says: 'The 30-minute streaming limit for this license is used up for this app run. Restart the app to stream again, or upgrade for unlimited streaming.' Restart and you get another 30 minutes.

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What is new in V8?

It is finally there! It has been a while since I shared that sneak preview around the holidays, and I appreciate everyone's patience. I have been beta testing for the past few months. So, here it is, thanks as always for your continued support and feedback:

V8.0.42: The Rob Reiner Edition.

You can grab the new version here: PGGB - Get V8 Here

This is a significant update with improvements in both performance and reconstruction accuracy. I will summarize the changes below:

Native Apple Silicon.

For those on Mac, PGGB v8 now runs natively on Apple Silicon. Previous versions ran under Rosetta emulation, which worked but left a lot of performance on the table. With native support, expect a 5-10x speed improvement on Apple Silicon Macs. This was one of the most requested features and long overdue given Apple will end support for Rosetta in 2027.

New DSD Modulators.

This is where most of the effort went and has the potential to affect sound quality. In v7, we had 5th, 7th, and 9th order modulators, with 9th order available only for DSD512 and above. V8 extends this significantly: modulators now go from 5th to 25th order, available for all DSD rates. They are organized in three groups: Low Noise, Very Low Noise, and Ultra Low Noise, with 6 orders to choose from across the groups.

What this means in practice: using the highest order modulators, quantization noise in the audible band drops to between -600dB and -800dB depending on the DSD rate, compared to -400dB to -500dB in v7 with the modulators that were available at that time. Reduced quantization noise improves reconstruction accuracy in the audible band.

I had couple of break throughs that allowed the design of the new modulators. The Very Low Noise and Ultra Low Noise Modulators now use a new modulator structure. The Ultra Low Noise modulators use even higher precision. The higher precision does come with higher memory requirement. I anticipate this can be a problem when combined with long tracks and higher rate DSD. So, a block processing mechanism is in the roadmap to allow longer tracks to be processed in blocks to get around memory limitations.

Speed and Efficiency.

Beyond Apple Silicon, the entire processing pipeline has been reworked with hardware acceleration. 256-bit PCM processing is now 3x-4x faster than v7 and uses about 25% less RAM, you can see PGGB 'fly' through your tracks now. DSD processing also sees a 10-30% speed improvement across the board (for 9th order and lower modulators).

DSD64 Support.

PGGB now supports DSD64 as an output rate. Previously DSD128 was the minimum. While I would still recommend higher rates when your DAC supports them, DSD64 and DSD128 with higher order modulators target playback systems that are sensitive to higher data rates but when the DAC sounds best with DSD.

Website Changes.

I have updated the website to better organize information, especially in the guide and FAQ section. I have also updated the page file size calculator to account for the additional memory needed for Ultra Low Noise modulators. As I mentioned before, the web page is now searchable.

Release Notes.

Version 8.0.42: The Rob Reiner Edition (PGGB Plus)

• SQ Changes: Possible through improved reconstruction accuracy of new DSD modulators
• Features:
  • New hardware accelerated processing pipeline
  • Native support for Apple silicon with 5x-10x speed improvement
  • PCM 256 bit precision processing gets 3x-4x speed improvement
  • Adds DSD64 support
  • Adds 9th order modulator for all rates
  • Adds a new class of modulator: Very low noise up to 19th order modulators, supported by all DSD rates
  • Adds a new class of modulator that operates at 256 bit precision: Ultra low noise up to 25th order modulator, supported by all DSD rates

Upgrades from V7.

If you purchased or upgraded a V7 license after January 1, 2025, you qualify for a free V8 upgrade to the same tier. Just email me with your name and Hardware ID. For those on older V7 licenses, upgrade options are available on the PGGB page. As always, there is a free 30-day trial that converts to a perpetual Lite license, so you can try the new version. V8 allows side by side install with V7, however V8 does not auto import your settings.

Looking forward to your feedback, especially on the new modulators. I am curious to hear impressions across different DACs and DSD rates.

V8 also adds a new tier 'Pro'. More details below.

Comparing V8 Tiers.

What is new in V8?

Will my DAC benefit from PGGB?

• High rate PCM and DSD: DACs that support PCM rates of 705.6/768kHz or higher and DACs that support DSD rates DSD256 or higher will benefit most from PGGB remastered tracks.
• PCM NOS: DACs that do little to no processing (such as R2R DACs that can be run in NOS mode) and DACs whose oversampling filter can be turned off will benefit significantly from PGGB PCM remastered tracks.
• Pure DSD: DSD DACs that have a pure DSD mode that can be enabled will benefit significantly from PGGB PCM remastered tracks.
• On DACs that support up to DXD rates and DSD128, remastering CD quality tracks using PGGB to DXD rate (352.8kHz) and DSD128 is likely to be beneficial too.
• If you have a DAC that supports PCM only, then you can use PGGB to remaster DSD to the highest rate supported by your DAC with excellent results.
• If you have a DAC that supports only 96kHz or 192kHz, you can use PGGB to remaster DSD or DXD files to rates that are supported by your DAC.

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Does PGGB support DSD upsampling?

Yes, PGGB currently supports upsampling to DSD or PCM rates.

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What is 1fS, 2fS, ..., 32fS etc?

One useful concept to learn is the terminology of FS. This refers to 'Fundamental Sample rate'. 1fS refers to 44.1 or 48 kHz. Thus:

• 2fS = 88.2 and 96kHz
• 4fS = 176.4kHz and 192kHz
• 8fS = 352.8 and 384kHz (DXD)
• 16fS = 705.6 and 768kHz
• 32fS = 1411.2 and 1536kHz
• 64FS = 2822.4 and 3072kHz

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How big are PGGB upsampled tracks?

As a rule of thumb, every 11 minute 25 seconds of a stereo track at 16fS and 32 bits or DSD512 takes up about 4GB of space. So, on an average typical CDs that are 40 - 45 minutes long will take about 16GB of space at 16fS 32 bits/DSD512 file. At 8fS 32 bits that is 8GB and at 8fS 24 bits it will be 6GB.

Remastered .wav tracks that are bigger than 4GB will be split, but the metadata is preserved and track numbering is changed so that they will play sequentially and in a gap-less fashion.

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Does PGGB support lossless compression?

FLAC supports integer output up to 32 bits and 768 kHz. For higher rates or floating-point output, PGGB writes WavPack instead.

PGGB also supports WavPack compression format for higher than 8fS rates or bit depth higher than 24 bits. WavPack compression is also lossless like FLAC.

PGGB will transfer all tags and artwork to both FLAC and WavPack output files.

What sort of PC will I need for running PGGB?

PGGB is a resource intensive application. It will benefit from as many CPU cores, as much physical RAM, and fast NVMe drives you can give it. That said, the application has been tuned extensively to scale to the available resources, so while a machine with lesser RAM or fewer cores may take longer to process a file, it will not fail, nor will the processing time grow exponentially.

Requirements depend on the processing engine, output rate, precision and desired speed. 64-bit Windows 10 or 11, or macOS 12 Monterey or later. Apple Silicon and Intel Macs are supported. Intel and AMD processors must support AVX2. A fast internal SSD helps with larger libraries.

Precision optimized upsampling (the default). With Precision optimized selected, memory use does not grow with track length and paging space is rarely needed. For Offline PCM up to 256-bit precision and DSD up to DSD256, start with a 4-core processor and 16 GB RAM. For DSD512, we recommend at least an 8-core processor and 24 GB RAM. DSD1024 and DSD2048 benefit from more cores and 32–64 GB RAM.

If you select Legacy under Settings → Processing, PGGB uses the Nyquist-Shannon engine. It holds the whole track at the working precision, so longer tracks and higher DSD rates need more RAM or paging space.

• PCM conversions: for tracks under about 12 minutes, a 4-core processor with 16 GB of RAM and at least 128 GB of free SSD space for paging may be sufficient at 128-bit precision. Memory and paging requirements roughly double at 256-bit precision. For batches of tens or hundreds of albums, consider an 8-core processor, 64 GB of RAM and 512 GB of free paging space.
• DSD conversions: allow at least 32 GB of RAM and 512 GB of free paging space for output up to DSD512. Requirements roughly double for DSD1024. For large batches, a 16-core processor, 128 GB of RAM and 1 TB of free paging space provide a useful starting point.
• For paging setup, see the guide for PC or Mac.

PGGB-Live. For Live PCM, we recommend an 8-core processor and 16 GB RAM. For Live DSD, we recommend a modern processor with 16 or more cores and 24 GB RAM.

Unlike a Music server, the PC that runs PGGB need not be low noise. PGGB will produce the same results no matter what PC it runs on. Here are a few examples Configuration PGGB is being used with:

• Ideal build (for PCM and DSD)
• Custom Quiet PC (for PCM and some DSD)
• Taiko Audio Extreme (for PCM)
• Quiet PC Serenity 8 Office (quietpc.com, for PCM and some DSD): Nanoxia Deep Silence 1 Anthracite Rev.B Ultimate Low Noise PC ATX Case. ASUS PRIME Z370-A II LGA1151 ATX Motherboard. Intel 9th Gen Core i7 9700K 3.6GHz 8C/8T 95W 12MB Coffee Lake Refresh CPU. Corsair DDR4 Vengeance LPX 64GB (4x16GB) Memory Kit. Scythe Ninja 5 Dual Fan High Performance Quiet CPU Cooler. Gelid GC-3 3.5g Extreme Performance Thermal Compound. Palit GeForce RTX 2070 8GB DUAL Turing Graphics Card. FSP Hyper M 700W Modular Quiet Power Supply. Quiet PC IEC C13 UK Mains Power Cord, 1.8m (Type G). 2 x Samsung 970 EVO 2TB Phoenix M.2 NVMe SSD (3500/2500)
• 2010 Mac Pro running Parallels (PCM): It was able to run PGGB with 6 cores and 32 GB of RAM but currently running 12 cores and 128 GB. Parallels was given at least 4 cores and at least 28 GB.
• For PCM and some DSD: Streacom FC10 Alpha fanless chassis, Asus Prime Z490-A mainboard, Intel i7-10700 LGA1200 2.9 GHz CPU, CORSAIR Vengeance 128GB (4 x 32GB) DDR4 SDRAM 2666, OPTANE H10 256GB SSD M.2 for Windows 10 Pro OS, SAMSUNG 970 EVO Plus SSD 2TB M.2 NVMe with V-NAND Technology, HDPLEX 400W HiFi DC-ATX power supply.
• For PCM: iMac Pro (2017) -- 3.2 GHz 8-Core, 32 GB, 1TB, Apple Bootcamp, Windows 10
• For PCM: iMac, 48GB RAM, 3.3 GHz four core i5. Running Windows 10 Pro under Bootcamp with a shared drive set up

With the legacy Nyquist-Shannon engine (Legacy selected under Settings → Processing), PGGB's memory requirements come from the need to accommodate input and output data, as well as the processing required to achieve near ideal reconstruction. Thus, the memory required is strongly dependent on:

• The sample rate of the source track: The higher the rate, the more virtual memory is needed
• The length of the track: The longer the track, the more virtual memory is needed

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Can you suggest a sample PC build for PGGB that is also quiet?

Sure we can:

• Be quiet! Pure Base 500, No PSU, ATX, White, Mid Tower Case. Caveat - It's a nice quiet case, but nothing great to look at.
• Prime B460-Plus, Intel B460 Chipset, LGA 1200, HDMI, ATX Motherboard
• Core i7-10700 8-Core 2.9 - 4.8GHz Turbo, LGA 1200, 65W TDP, Retail Processor
• 128GB Kit (4 x 32GB) HyperX FURY DDR4 2666MHz, CL16, Black, DIMM Memory. Caveat - can easily start with 64GB
• 750 GA, 80 PLUS Gold 750W, ECO Mode, Fully Modular, ATX Power Supply
• Be quiet! Dark Rock 4, 160mm Height, 200W TDP, Copper/Aluminum CPU Cooler
• 2TB 970 EVO Plus 2280, 3500 / 3300 MB/s, V-NAND 3-bit MLC, NVMe, M.2 SSD

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Can I use the Taiko Audio Extreme to run PGGB application?

As extreme as the Taiko Extreme is, it is not quite extreme enough out of the box to run PGGB. The Extreme has a stripped down installation and memory configuration that is optimized for SQ during playback. PGGB consumes all available system resources (and then some). The good news is that you can install PGGB on the Taiko Extreme and run it when you are not listening to music and not impact SQ.

To get PGGB to run on the Extreme, you must configure a paging file when upsampling. By default, the Extreme has the paging file disabled to maximize sound quality. To run PGGB, you will be turning on a paging file, running PGGB, then disabling the paging file and rebooting, then listening to music on your Extreme as you normally do (for convenience, you can listen to music with the paging file on, but there may be some SQ impact).

To turn on the paging file on your Extreme, from the Start menu, follow the following path: Start -> Windows System -> Control Panel -> System -> Advanced System Settings -> Advanced -> Performance Settings -> Advanced -> Virtual Memory Change

Select the drive on which you want to put the paging file (C: drive usually), and select "custom size." Set to 135000 for both min and max. Click OK and you're paging file is ready to go. When you turn on or increase the size of the paging file, you do not need to reboot. If you shrink it or disable it, you will need to reboot for the change to take effect. Note that the default configuration of the Extreme has the paging file disabled, because it could impact SQ. For best sound quality, turn on your paging file, run PGGB, then turn it off and reboot before listening to music.

If you're doing a lot of PGGB work, give a listen to playback with and without the paging file to decide if the inconvenience of rebooting your system prior to music playback is worthwhile for you. At 48GB, the Taiko Extreme is at the minimum amount of memory that you need to run PGGB. Typically it does OK, but upsampling DXD files or processing DSD files pushing the system to its limits. If you're processing overnight, you won't notice, but enjoy a cup a coffee if you're sitting there waiting for these more intensive processing jobs to run.

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If I had both PCM and DSD versions of an Album, which do I choose to remaster?

Regarding DSD... there are so many factors that come into play: original recording format, original editing and mixing format, your DAC, etc., etc. Ultimately, it all boils down to a couple of key considerations:

• Is the DSD album the best-sounding version in your library? If so, just upsample with PGGB - it will uplift SQ.
• If you also own PCM versions of the album, or are aware of other PCM versions, by all means explore upsampling your best-sounding PCM version with PGGB, and then choose the best-sounding upsampled versions.

A couple of examples from a user experience may help. Below is are direct quotes:

Example 1:

Mahler 2nd, Gilbert Kaplan, Vienna Philharmonic, DG hybrid SACD. I don't know the details of the recording, editing, and mastering format. Played natively to my DAVE in DSD+ mode, the DSD layer sounds best, with the CD layer played in PCM+ mode second best. I upsampled both versions to 32/705.6 with PGGB, played back natively on DAVE in PCM+ mode (of course), and found the following to hold: a) the upsampled DSD version still sounds better than the upsample CD version; b) the gap between the 2 versions shrunk. In other words, PGGB did more good to the PCM version, but the improvement to the DSD version was still extraordinary.

Example 2:

Das Lied von der Erde, MTT, SF Symphony, recorded in DSD64, but unclear what format it was edited and mixed in. I suspect it was PCM, but not sure. I own 3 versions: DSD and CD from the hybrid SACD, and 24/96 hi-res version purchased from Qobuz. Played natively on my DAVE, I find the 24/96 (2fS) version to sound best, with the DSD version 2nd best. After upsampling with PGGB: a) The upsampled 24/96 version reigns supreme. b) The gap between the upsampled 24/96 and upsampled DSD is greater than the native gap. This again suggests PGGB's ability to impart magic is most with PCM, but DSD is also uplifted.

Bottom line in all of this is: Pick the best sounding version of an album in your library (irrespective of PCM or DSD). Where it's close or equal, always prefer the PCM version.

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Does PGGB support multi-channel music?

PGGB currently does not support multi-channel PCM or DSD, but it is relatively easy to extend it to support multi-channel. If there is modest demand for it, or a requirement for a commercial application, we are open to offering multi-channel support. Just drop us an email.

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Do you use Matlab?

PGGB has not used MATLAB since V7. The interface uses Qt, and the processing engine is written in C/C++. The processing core works on Windows, Mac and Linux; the PGGB desktop application is available for Windows and Mac.

PGGB-Live provides real-time playback with processing up to 256 Bit precision, subject to your license and the speed of your computer. Offline processing creates files that you can play later. Higher precision takes more processing time; the Precision optimized engine keeps memory use from growing with track length.

To compare processing speed on your computer, use the same track and output settings at different precision levels. The processing logs record the elapsed time. See the calibration guide for Live playback and the system requirements for computer recommendations.

It looks like PGGB can process really fast, can it do this on streamed music?

Yes. PGGB-Live processes music while you listen, using local files, a compatible player through the PGGB Bridge, or a UPnP control point. It sends the processed audio to a local DAC or a network endpoint. For network output, use PGGB-Audio-Link (PAL) where available, with UPnP as the fallback. See the Live guide for setup.

The foo-pggb-rt plug-in for foobar2000 is still offered, although it is no longer actively developed. It processes at 64 Bit precision.

PGGB is also available as an SDK for OEM integration, with C++ headers and static libraries for Windows, Mac and Arch Linux.

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Are linear phase filters better for upsampling?

The explanation below describes the Legacy engine. For the current default engine, see the Precision optimized engine explanation.

Upsampling requires a low pass filter (to interpolate intermediate samples). The purpose of the filter is to provide good estimates of the intermediate samples so that the upsampled signal is smooth and as close to what the original music signal would have been.

There are several ways to implement the low pass filter and each method has its pros and cons. Linear phase filters maintain the phase relationship of the original signal and tend to preserve the timing of the original signal, resulting in improved imaging precision. Minimum phase filters when compared to linear-phase filters of the same length, have better frequency domain performance that results in better tonal accuracy and a denser presentation.

For the above reason, for short lengths, minimum phase have a significant advantage over linear phase filters. With longer filter lengths, the choice becomes more subjective and comes down to preference and synergy with the playback chain.

With, the ultra-long windowed Sinc based linear filters such as the one PGGB-AP uses, it is possible to get very close to the original, as if the music was recorded at a higher sample rate. As a result, the ultra-long filters pull ahead of other implementations in terms of realism and accuracy.

The ultra-long windowed Sinc based linear filters come with a significant cost in terms of latency and computational requirements, which make them hard to use for real-time playback. However, for offline upsampling and remastering, they are an excellent choice.

PGGB use a proprietary method different from the above methods. PGGB is non apodizing and it does not use windowed sinc functions, or long filters either. The best way to look at the current approach used by PGGB is that it considers the track as a whole. If no HF filters are enabled (which is the default for CD and 2fS rates), PGGB keeps all of the original samples intact, then creates intermediate samples all at once by time shifting all of the original samples. Our method approaches the theoretical limit of reconstruction accuracy possible for a track of given length and sample rate. This is more accurate than using pure Whittaker-Shannon coefficients with windowing. As the sample rate increases, and the track length increases, our method approaches the mathematical equivalence of using pure sinc based interpolation.

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Why use noise shaping? Is it same as dither?

Both dither and noise shaping can be used to reduce the audible effects of quantization (i.e., digital noise). Quantization noise is introduced when the remastered track that resides in memory in 64-bit floating-point precision format, but needs to be output at 32-bit integer precision or lower. However they work in very different ways. Dither is the process of adding an intentional small random noise to randomize quantization noise. This serves to decorrelate the music signal and quantization error, resulting in a more natural sound. Dither does not reduce the quantization noise, it just helps to mask it.

Noise shaping does not simply mask the quantization noise, but it instead pushes the noise out of the audible range. Well implemented noise shapers can almost completely eliminate quantization noise from the audible range. This helps preserve and reproduce even the smallest of changes accurately, resulting in a clean and almost analog like quality. While noise shaping provides better results, unlike dithering, noise shaping is available from 4fS (176.4 / 192 kHz). At 1fS and 2fS, use dither only.

PGGB uses specially designed higher order noise shapers that are optimized for output sample rates and bit depths and are designed to almost completely remove quantization noise from the audible range.

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What is a 'HF Noise filter'?

HF noise filter refers to 'High frequency' noise filter. Most Hi-res recordings (4fS or higher) contain a significant amount of residual noise (beyond 30kHz) as a result of noise shapers used during analog to digital conversion process. There is no music information contained in this noise. So the HF noise can be safely removed, and has a positive effect on sound quality.

PGGB offer a choice of three HF noise filters. However the HF noise filters are not applied separately, instead they are integrated into the design of resampling process. Just like adding more elements to a camera lense can reduce transparency, using additional filters can reduce transparency. So PGGB uses a single optimized process that does both reconstruction and HF noise filtering for the most transparent sound.

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Does PGGB support lossless compression?

Yes. PGGB writes FLAC, which is lossless: the file is smaller, and what comes back out is bit-for-bit what went in.

V9 raises how far that goes. FLAC output now supports PCM up to 768 kHz and 32 bits, so most rates you are likely to use can be compressed rather than left as WAV. Pick .flac under Settings → Offline → Output files → Output file format. For rates above that, use WAV or RF64.

For DSD, the equivalent is .wv (WavPack), which is also lossless. Plain .dsf is uncompressed.

Does PGGB use Apodizing filters?

PGGB does not use apodizing filters.

Apodization in Greek means cutting off the foot. It has different technical meanings depending on the application. In Signal processing, it just means using a windowing function to reduce ringing artifacts due to the abrupt truncation at the beginning and end of a sample window. In digital-audio, the term has been used and also misused. In digital-audio, more often than not 'apodizing' is used to mean it is a non-brick-wall filter which has reduced or no 'pre-ringing'. It is implemented as a slow-roll off filter.

The long technical pieces live on a page of their own, alongside the theory sections from the guide.

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So long and thanks for all the fish

.·´¯·.´¯·.¸.ZB.´¯·.¸¸.·´¯·.¸><(((º>