What do most people use HQ player for?

Just noting this related thread:

The linked post contains graphs of the output of a non-oversampling DAC giving the clearest explanation/demonstration of the benefits of upsampling that I have seen.

I use HQPLAYER so I can see my DAC display 1.536mhz or DSD512! :grin:
I wish I was joking.


I totally understand lol

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I don’t use HQ player.


For me it’s upsampling and to set different filters/Dither/modulators for PCM and DSD playback.

  • Convolution engine, for active speaker DSP crossover

  • Convolution engine, for active speaker room correction

  • Parametric EQ for headphones and other headphones DSP (like Bauer cross-feed sometimes)

  • Input feature for any kind of source (not just Roon) like Spotify, Apple Music, Soundcloud

  • Doing 100% all digital filtering in PC, by-passing DAC internal DSP (with my RME ADI-2)

  • Digital volume control for all the above

I’m sure I’m forgetting something :grinning:

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I am using HQP as the final touch after all being done in correcting the digital highway, to achieve not a minor, but a fundamental audio enhancement. As a noob, I still cannot utilize all features listed above in dabassgoesboomboom, but the one’s i do use, play a profound role in establishing what I for a long time thought, but now are able to hear, most recordings are actually quite good.
The HQP “washing machine” allows me to listen to albums and tracks that with the normal audio equipment I had in the past, was pure torture to listen to. Laser sword cutting high notes and much too boomy bass. After giving up on commercial hifi gear, I bought studio gear and built computers while going in to the depth with what makes digital stream poor.
Now, there is not one single track that I cannot enjoy, even if I sometimes wonder what the heck were the crew thinking about while post-processing the files. HQPlayer would be the one and only software player and enhancer if I had to choose. It is a game changer …


I am just thinking about what you wrote: if you have nasty digital recordings in your collection and they are much improved by using any of those filters provided by HQP, what happens to the good sounding albums? Will they be altered to the better as well? Or do the sound untouched other than altering the sample rate/bit depth?

All music, good mixes and masters, as well as … eh … not so good ones benefit from HQplayer. The really bad ones, starts to be possible to enjoy, the good ones, takes you to heaven.It is almost like an x-ray, it will reveal every and any corner or hidden notes in the music.
The only thing that I have found will lower the listening experience is at HiFi rig that is not silent enough in itself. Since the details in the music arrangement is often subtle, the gear that presents the work from playback and resamplimng in HQP must not be affected from the domestic noise, that we have in an abundance. I am a developing engineer for a Swedish company (will not make any PR here) with the aim to with external devices lower or even eliminating the impact from all the noise sources. Myself I clearly differents the sound from my studio monitors for each and every filter I use, only when I have the equipment connected. If not I can tell the difference in most cases and in some I am having a hard time. Even if the filter i improving the digital bitstream, the reamaning signal path will add noise to a level where the most subtle details drowns and will not audible. In forums on Facebook I am attending, I recognize from all the comments that every person is somewhere along the silence scale depending on how they perceive the impact from HQP. Me and some of my engineering friends have come a long way no in order to isolate the most aggressive noise sources and are nothing but blown away by the HQP impact. As I said it is for us a game changer. But, I am fully aware that the same impact will not be true for some other users who have not (yet) understod how inferior much of the home HiFi internal noise filtration is working. Making music pure and clean is a multi-task of maintaining the signal integrity through the entire music rig and understand the difficulty that is, from a engineering and science point of view. Most of the nasty recordings are not nasty, when you got control of the playback system, and e.g. any over-energetic high notes will stop ringing because you have stopped the resonances. Most “nasty” recordings have been produced in a way that will trigger improper circuitry in your gear. Myself I have lived since the launch at MTV with Peter Gabriels Sledgehammer as a really nasty recording, and also e.g. Chris Rea’s album, The Road to Hell. The over-energy and sibilance used to be insane, say 6 years ago playing from CD-player. Now, a couple of days ago, I suddenly discovered earlier un-heard details in the arrangement, that never showed before. All balanced in a way impossible to achieve before HQP (and the extensive re-engineering of the critical noisy parts of my rig). You will enjoy the difference to, but I cannot guarantee how much you will experience from HQP alone, it is co-dependant of many others parameters as well.

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Thanks for your detailed answer!

So what you’re saying is that to fully appreciate HQP, and to be able to distinguish between the various filters, one needs an absolutely silent audio chain, correct?

If that is not the case, HQP can be forgotten about, correct?

I am on your side! After struggling with noise in my system, I finally found the culprit and things got very enjoyable. So I made the leap, despite the wealth of (for me confusing) filters and tried simple PCM > PCM upsampling based on poly-sinc filters. I must say, I was amazed of how much detail I could discern in some recordings. Also, overall sound got a bit smoother, containing less of digital harshness.

So, what do I do with this information? Given the bewildering number of filters, which ones should be tried to (maybe) achieve even better results?

This, at least for me, is HQP’s bottleneck!

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The choice of filters and dither is a question of the DAC used, i e how high should I resample, PCM or DSD, etc. That is the tech side of it. Some DAC technologies like an older pcm multibit DAC like my Benchmark benefits from NS9 dither, pretty much tailored for the DAC.
Then there is the personal taste. There are minimal phase filters with accentuated transients, or linear phase with more emphasis on sound stage. I prefer linear phase, there are a few that still have good transients. Poly-sinc-EXT2 is one, I used for a longer period of time. Lately, while evaluation an new device prototype, it extended the silence soo much the enrgies in tracks shifted and became even more obvious, hence tried the Sinc-M. Heavy on computer, l o o o n g filter and long latency just starting up the track, but boy how rewarding for the sound. The ones I have tried, since I am in the PCM-corner of the filters, is Closed form-variants, Poly-sinc-EXT2, Sinc-S and Sinc-M. For my JBL studio monitors I always end up with a dther called Shaped. Replaces DAC conversion noise with a smart evaluating dither only as much needed. Feels almost like the mastering term “digital black” when playing very dynamic music in sections where the is very silent. My Benchmark DAC1 however like Sinc-M and NS9 when I listen in my closed back studio headphones.
As I have been a critical listener for a number of years, also a HiFi product developer, I know well what to listen for and also often why certain sounds get exaggerated, so I start to be able to decide where to direct my efforts; filters or sometimes even solder iron in the device. I am 58 years, so it is about time I guess … :sweat_smile:

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Thanks Stefan for your explanations!

It’s astonishing how much overlap we have! PCM or DSD is the first choice one has to make. I personally stick to PCM for the moment. My DAC (Devialet) would be able to handle DSD64, but for the moment I stick to PCM.
NS9 was my first dithering choice and, as you say, my DAC benefits from clearly having a better soundstage. Out of curiosity, I switched to NS1 and the sound became edgy and much too bright! I was astonished just to see how much difference dithering can make!

My gripe with HQP is this cryptic filter nomenclature. What in devil’s name does poly-sync-ext2 mean? I know, at least from mathematics, what a sinc function is, but it doesn’t define the filter very well. Also poly-sinc, I just don’t get a clue what that could mean.

Wouldn’t a systematic nomenclature help thee users better by dividing the filters with a nomenclature that most audiophiles understand. Say, the filters are divided into linear or minimal phase, and from there, further subdivisions are made. The way the filters are named is just a shambles.

I keep experimenting, in small steps and I hope my prayer for a logical filter nomenclature is Heard- in the DSP heaven :grin:!

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Have you read the manual?

To explain beyond what’s in the manual, I think Jussi would need to write a DSP textbook.

This is exactly explained in the manual… One screenshot from the manual:

Yes I have!

But now that you mention: the common denominator of the page you show is poly-sinc. I‘m just wondering what ,poly‘ stands for. Again, sinc is known to me to be a mathematical function (sin(x)/x), I just would like to know what poly stands for.

And now upon closer inspection, I see the terms lp, which is linear phase, and mp which is probably minimal phase.

OK, I‘m getting there!

Thanks for your help!

I can’t go through the entire manual for you but what I shared above is just one page.

So that page refers to “poly-sinc” filters and if you traced things backwards (in the manual…) you get to:

So here you see (in the manual…) poly-sinc refers to polyphase sinc filter…

The general theory of a polyphase filter is not unique to HQPlayer… you can Google and find explanations on polyphase sinc filters and in textbooks.

I don’t mean to be rude but I think it’s a bit unreasonable for Jussi to include a digital filtering textbook in the manual.

I’m guessing it’s short for polyphase

jussi has some info out there about the special filters like ext and xtr.

OK Let’s leave it at that!

Super, thanks, polyphase that rings a bell.


I have googled the words, that did not mean a thing to me. By reading a lot I managed to figure out the very thinnest layers of content, but Jussi is a busy man, an adequate manual for what everythings mean should keep hom occupied a while. Not that it is not wanted, I would lova to dive deeper, but have resigned and accept that some guys know enough to make this for me. Together with some of the wonderful people here, I am still in school, many thanks for the patience. :slight_smile: :heart:

My use of HQP has changed since I first wrote in this thread many years ago. I’ve been using a Holo Audio Spring I DAC for a few years and am currently thinking about a May.

The Spring has separate R/2R boards for PCM and DSD, meaning that the DSD input is never converted to PCM. It also has a NOS setting which completely bypasses internal oversampling. The result is about as minimalist as you can get in a DAC. Everything is done in HQP.

In HQP the Settings I use are ext2, ASDM7EC, DSD 256. This is a very popular choice and sounds very transparent and natural to me. I am using a dedicated (Roon and HQP) Server with an i7 7700 (not K) with a GTX980 graphics card for CUDA, running Linux Ubuntu 22 with Jussi’s low latency kernel.

I get an occasional dropout when playing streaming source material above 48k. Local hires has no dropouts. The dropout only occurs when a track is loading at the start of an Album. I think it has something to do with the way my ISP delivers the data and how Roon buffers it.

I have used convolution with a room treatment WAV in HQP in the past, but am not using it at the moment. I have active bass speakers and am still finding the best gain setting for quiet and medium volume listening. I will probably do a new series of sweeps and have Thierry at HAF do some filters.