Which HQP Filter are you using? [2015-2023]

Thread to discuss which filters and modulators we are using in HQP and why.

The filters are described in the HQP Manual. There is a link to the Version 3.1 manual in the Signal Chain footer in Roon. The latest version of the manual, including descriptions of later filters, can be found in the HQP folder.

Geoffrey Armstrong’s KIckstart guide contains some basic information about setting up HQP.

These CA threads also contain useful information and discussion about the filters:

Jussi/Miska’s guide to the settings
HQPlayer filters, dither and settings

So far I have tried the filters described below (all upsampling Redbook local and Tidal to DSD128 into an Auralic Vega using ASDM7).

closed-form and closed-form-fast
I thought these had the biggest space/soundstage. Huge tracts of land !

Edit: Compared to poly-sinc-shrt-mp I hear some increased harshness in high frequencies with closed form. I suspect it’s because of the extra processing it requires and it might not appear with more powerful hardware.

Very intensive on the CPU, starts the fan on my BRIX. I couldn’t distinguish fast (lower CPU) from the original. These are non-apodising filters (meaning noise from the ADC process is left where it was). I understand the WTA Filter used in the Chord DAC is a closed form interpolator.

Spacious but I prefer the linear phase poly family below which seems more detailed.

poly-sinc, poly-sinc-shrt, poly-sinc-hb, poly-sinc-ext
Spacious and detailed. These all sound good, but I keep gravitating back to poly-sinc-ext.

poly-sinc-mp, poly-sinc-shrt-mp,
Rock and Roll baby ! Dynamic and detailed. Poly-sinc-shrt-mp is my go to for anything driven by drums/percussion.

Edit: These filters really shine with decay. Most beautiful trailing sounds I’ve heard from my system.

Dynamic but prefer the poly-sinc-mp family.


13 posts were split to a new topic: Why do audiophiles like HQ Player?

So I downloaded the beta last night. Now I only have a PCM dac (NAD M51) so I was unable to upsample to DSD which must be what makes HQplayer sound so good. My initial thought using poly sinc MP filter, up sampling red book to 192 was did I turn the amps to my woofers on? Thin, transparent sound that lacked involvement and pace and drive. I tried a bunch of filters and could hear differences among them and some sounded pretty good but I felt Roon by itself was equally as good or better. Lots to still try tho and each does change the sound so we’ll see.

Does anyone else feel the PCM up sampling is just so so?

When I initially tried it I upsampled to 88.2 kHz (2x) and couldn’t hear much difference vs Roon direct. Then I changed to 96kHz - and it sounded a whole lot better! I can’t explain this at all…

(96 kHz is the maximum rate of my Musical Fidelity V-Link II USB adapter. The Musical Fidelity V-Link 192 has been discontinued, so I just ordered a Peachtree X-1 adapter to deliver 192 kHz to my DAC.)

I’m upsampling to either 192 or DSD with the filters that I like. To me the 192 is a noticeable improvement. But it is all system, DAC, and personal taste dependent. In your case it could be that the DACs own filters are closest to your taste. But experiment a little more, you might find a combination you really like.

I only have a 96/24 DAC and hear improvement with HQPlayer over Roon. The main improvement are with soundstage and precision of instruments. The overall sound is somewhat close but with HQPlayer, each instrument is clear and in it’s on space. Roon has sort of a blended sound. It’s not bad at all but with HQPlayer, it sounds amazing. Also, depending on the filter, I can move the soundstage closer or make it more spacious. For me, I prefer the close sound of poly-sinc short.

So I’m using:

poly-sinc short

I’m curious to hear what DSD can do but I’ve got a high-end headphone setup where the DAC/AMP is matched to the headphones (AT L3000/DHA3000) so I may lose something swapping out equipment.


As I mentioned earlier I have a NAD M51 dac, PCM only no DSD decoding. On its own it up samples any incoming PCM signal to a PWM (Native format of DSD) at 844Khz. I have a very resolving system with a very large sound stage. It surprises me how much difference there is among the various filters. Last night the first one I tried I did not like at all, forgot to write that one down. Then I went to Poly-sinc-shrt-mp with NS9 dither this was more like it. Body was back, bass was nice, imagining was close to what I am used to. Then I played a acoustic piece with just 1 female singer and 1 guitar. it was a reference that I have played many times on my TT and heard on CD lots as well. Her voice sounded wonderful but the guitar was placed very forward of the singer and with the vocal microphone picking up some guitar as well as the guitar mic, it almost appeared to be two guitars one left forward of singer and one right forward. I changed the dither filter to NS4 and that tightened up the guitar so it was more like one larger guitar. I then changed the filter to Poly-sinc-mp with ns4 dither, this made the sound more like I was used to off my LP reference. Then I went straight roon (no HQplayer), chuckled and preferred that over both filter variations above. Sound had more dynamics, the voice was more 3D with that “palpable presence” the guitar was left but in the same plane as the singer, it is slightly large due to the splash the vocal mic picks up as expected.

I must say the 30 minute time limit on macs makes it difficult to do a lot of testing (more tedious, I guess). I listened a lot last night to HQplayer and for the most part it sounded very good. The last 30 minutes of the night I went straight Roon and replayed some of the same tracks. I still prefer Roon direct, now I am getting HQplayer to sound very good and there is still a lot of combo’s to try. I do know I really do not like the poly-sinc and poly-sinsc-shrt filters. The sound is thin and closed in, which makes no sense as the descriptions says space.

Ah the mysteries of Hi end audio.

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The filter options are many and what still surprises me is the audible difference between them. In most cases the change is not subtle where you have to listen really closely to hear differences. I can think of almost nothing in the pure analog world that can offer those types of changes except possibly a phono cartridge shootout and even that may not offer up the differences these filter changes can. Now let me say in most cases you can say HQplayer offers a bit to a fair amount more transparency than Roon by itself, but usually there is something in that presentation that I feel takes away from the music experience, usually it leans more on the “it sounds like really good recorded music” with HQP and with Roon it is more organic and real like. Kind of like HQP is really good digital and Roon more like really good analog.

Last night I hit on a combo, possibly two, that may make me say HQplayer finally exceeded Roon direct and it is not where I would have expected to end up by reading the filter descriptions. My notes say 1 and 1A and they are Fir and NS4 (1) and FFT and NS4 (1A). These kept the energy and dynamics of Roon itself, upped the transparency and equaled the sound stage. I was impressed. Then HQP started acting up and sound came from my computers speakers rather than the big rig and nothing, Audio midi, close down restart programs, reboot computer fixed it. So I finished the session with Roon alone and it was really good as usual, but I found myself missing something those filters in HQplayer provided.

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I think I know what happened when HQP played thru computer speakers. Apparently one one of the many restarts (darn 30 minute limit) HQP switched device to internal speakers and I did not pay attention to that, just confirmed roon zone and audio midi output. Sometimes the most obvious is so hard to find.

I’m really liking the poly-sinc-mp filter using ASDM7 and DSD128… so much so, I just bought the HQP license, since the 3.12 final release, I’ve had no issues on my MacMini at all.

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I’ve been listening to classical. I’m finding closed-form-fast and DSD5v2 for Redbook to DSD 128 to be very spacious and resolving, without overtaxing the CPU and introducing harshness into the high frequencies.

After playing around for 12 plus hours with that 30 minute time limit, I bought a license and currently up sampling only to 192 pcm since dac is not dsd capable. I am finding minringFIR with NS4 dither to be sounding just wonderful. Listening primarily to blues, jazz and rock. Not sure why I don’t find the poly-sinc filters to my taste/liking.

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I have after a few days with HQplayer found that it still sounds best without additional software upsampling and filtering to my DAC. Strangely, even with this, the HQplayer sounds better than playing just through ROON. Not sure why since they should be both streaming bit perfect???

In terms of upsampling, I find DSD better than higher rates of PCM. However both sounds more muddled than just native through to the DAC for me. I also loose a bit of the 3 dimensionality of individual instruments when upsampled.

I use a Chord DAVE streamed from a MAC mini. Perhaps the MAC mini is overwhelmed. Its a dual core i5. But looking at the activity monitor it shows up to only 20% of core being used.

I just installed HQP. Why the windows settings is so small? (almost unreadable). My screen resolution is high and probably there is a scaling problem, but don’t matter what I do, the settings size does not change. I have a Surface book with a screen resolution of 3000 x 2000

I also find the sync filters annoying as user above.
My three best PCM combinations:

FIR + Gauss1
Sync + Gauss1
Polynomial-1 + Gauss1

Protip: ignore the recommendations in the manual, they lead you to technical correctness over what actually sounds good.

So if you see a “not recommend” do try it.
Begs the question why it would be there in the first place? Like some sort of filter museum.


Great suggestion! FIR / NS4 really make Roon-HQPlayer sing in my setup. Thank you…:grinning:

Thank you Andy for suggestion. It sounds absolutely amazing on my setup. Redbook to DSD 128 with closed-form-fast and DSD5v2.

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Just started using HQPlayer and I’m really liking ploy-sinc-ext for upsampling pcm to pcm.

Note, some choices of over sampling algorithms will cause the resulting stream (of converted 24/96 and 24/192 pcm) to be unusable by the PS Audio DirectStream Dac (and probably others). If you hit this problem, don’t panic just revert to settings that do work. Another important tip: when you change any choices in HQPlayer and minimize it to return to the desktop, restart the Roon Server software by double clicking the icon before trying out your changes.

Here are the settings that I have settled on at this time, after a fair amount of trial and error.

First, on the main page there is a line of four settings without labels (but if you hover your pointer over them the labels appear). They are Oversampling, Modulator, Sampling Rate, Sample Format/Type. Don’t worry about the first three as you will address them in the Settings window, but the Sample/Format/Type should be set to SDM (DSD). This will tell HQPlayer to convert all of your PCM format music to DSD format.
Under the File tab there is a Settings selection – here are my current choices: SDM Pack: DoP, Buffer: Default, DAC Bits: 32, (ignore the PCM Defaults as you are outputting SDM); In the SDM Defaults box – Oversampling: Poly-Sinc-shrt-mp, Modulator: ASDM7, Bit Rate Limit: 44.1×128, vol max: -3db, multicore DSP: check.
Under the File tab there is a DSDiff/DSF Settings selection – here are my current choices: Direct SDM: check, Conversion Type: Poly-short-lin, Noise Filter: low, Integrator: IIR.

Good luck and please share.

Over the last few days I’ve been listening to the poly-sinc-xtr-mp-2s filter using AMSDM7 512+fs modulator, upsampling to DSD 512 and native DSD to the mR and then into the NOS Holo Audio Spring.

This is my new favourite setting. Gobs of soundstage and space, clear sparkling highs without sibilance and revived lower end impact and weight. Jussi has noted the xtr filters are down .1 dB at 21.5 kHz.

Roll on the SonicOrbiter 2.5 upgrade, which fixes the Linux native DSD pop (this was a coding error in ALSA that sent PCM silence signal instead of DSD silence at commencement of Play; fixed in kernel 4.10). I use Add Next or Add to Queue to avoid it or mute the preamp.

Using an i7-7700 (23-30% CPU) and a GTX970 (0-59% GPU) with Multicore and CUDA enabled. Also convolving a wav room correction file in HQP. Unoptimized Windows 10.

@MusicEar, Guy have you heard the Spring with these settings ?

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