Why do audiophiles like HQ Player?

I’d suggest upsampling Redbook PCM to 192 kHz and trying the poly-sinc-2s and poly-sinc-mp-2s filters. They are less intensive versions of the poly-sinc filters.

Same for other PCM? Upsample 24/48, 24/98, 24/88, 24/176 using the same filter or is it different filters for every resolution? That would be pretty difficult using it through Roon, right?

I tend to stick to the poly-sinc family, but you can try out other filters by all means.

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I’m just trying to understand the theory behind these filters. Are they intended to only be applied to certain sample rates?

Not in my case. I’m using the poly-sinc-short-mp, ASDM7, DSD128 and it sounds great with everything I’ve played… Like you I’d have no interest in changing filters all the time for certain songs, personally I haven’t time and/or interest in doing that.

In my system this combo has just seemed to relax the digital harshness that can occur and creates more depth and a more immersive sound I believe.

It’s easy to start with the poly-sinc family and play some tracks with Roon only, than Roon w/HQP and if you don’t find a difference for the better, easy… No need to go further.

Are the filters additive?
What sounds best?

It depends what you ask HQP to do and how your DAC works. Most DACs upsample to 8X PCM rates(in 2X steps), then to DSD, the convert the DSD to analog - even if they say they are non-upsampling.

My DAC will just turn the DSD to multibit DSD and convert to analog if fed DSD - so that allows it to skip a lot of steps of processing. YMMV with your DAC.

What sounds best is totally individual. You have to experiment and see. Personally, usually listen to playlists -sometimes created on the fly - so I have one or two setups in HQP that I like, so I just set it to one of them and use it continually with all sample rates and formats.

There are people whose listening is almost all album oriented, so they change filters according to the type of music - say FIR filter for classical, or poly-sinc for other types of music.

[quote=“andybob, post:5, topic:6210”]
A reconstruction filter can also shift noise from the ADC conversion into inaudible frequencies, in which case it is known as an apodising filter.
[/quote] I always thought that an apodizing filter was one with a slow roll-off, essentially to reduce the ringing caused by brick wall filters (the term comes from radio astronomy).

Wikipedia says the literal translation of Apodization is “removing the foot”. It was first used to refer to removing airy diffraction disks in optics but has become generalised to mean changing the shape of a mathmatical function, including the filters in digital audio. One way of changing the shape is to shift noise to higher frequencies, another is to “minimise pre-ringing”. Jussi refers to his closed form interpolator as a non-apodising filter because it is “bit-perfect” with the data and doesn’t shift noise. I gather (but may be wrong) that an apodising filter is a trapdoor function and you can’t recover the original data from the convolved result.

I have a PS Audio

Direct stream which upsamples everything to did already. Why should I need HQP?

Sorry, I mean DSD

Have a read of this thread and the other threads in the HQ Player section. Basically many people have found that the reconstruction filters in HQP are better than the filters in their DAC.

Fritz, if you’re using PCM then the cpu load is usually not too bad (DSD is apparently much more cpu-intensive).

The HQP designer summarizes his settings recommendations within this detailed thread

’Generally, I recommend choosing between “poly-sinc-…” filters and using highest possible sampling rate. Dither or noise-shaper chosen based on above description, “NS9” for 192 kHz output, “NS5” for 384 kHz output and “TPDF” or “Gauss1” for any lower rates.'

Note he recommends the highest possible [up]sampling rate (regardless of source) - so you can just choose one setting like this, and leave it alone. Eg, if your DAC supports 24/192 - try the default (topmost) poly-sync filter, choose NS9 for the dither/noise-shape - compare that to Roon direct (exclusive mode, etc) to see if it’s a significant improvement for you.

Just to clarify. That is where CHORD started. The Hugo has 26,638 taps in the FIR interpolator. Not sure about the 2qute but I believe it is the same. the DAVE dac on teh other hand has even more.

The 16k taps is input-relative. So in order to obtain equivalent final number of taps you need to multiply that with the oversampling factor. Which for DSD256 and RedBook source is 256x; thus resulting in 4M taps.

HQPlayer automatically modifies the filters based on source rate to match the desired output rate.

Hi @jussi_laako, great to see you pop in here!

Speaking of desired output rate: for now my DAC maxes out at 96/24 PCM. I find that 44.1 material is auto-upsampled to 96 – shouldn’t 88.2 be better in this case (or shouldn’t I worry)? Using poly-sinc-short(-mp) with NS4.

Smallish question on the side: I’m running a Pi as NAA. Is v 2.0.5 still the most recent package version?

Not so sure all audiophiles goal is transparency, otherwise I would have been very happy with any filter in HQP as they all seem to offer slightly to a lot more transparency. It still comes down to the music, and our goal, I think, is to bring the performance into our rooms as it was when recorded. Now we were not there during the recording but we all have a good idea of what live music sounds like and whether it was a intimate studio recording or an attempt of a real live concert performance. We all have our prejudices as to what we like and our systems evolve on these two ideas.

HQP offers a LOT of choices, I cannot up sample to DSD as my dac will not do DSD, so I up sample to PCM 24/192, my DAC takes this signal and converts it to a PWM (native DSD) at 844Khz. I Have tried lots of filters in an attempt to find one or two that will work for me in most if not all cases. I certainly do not want to be changing filters for every song or every native resolution change. I think I have found some combinations that add to my enjoyment of the musical performance, making it more you are there, more real to me. When I go back to Roon by itself I feel something is missing. In fact I bought a license today for HQplayer. It took me probably 10-12 hours of listening to find what I felt were better filter combo’s for my dac/system/prejudices.

I cannot tell you what filter is best for your dac or personal prejudices, you should use the trial period and see for yourself. You may actually enjoy the process and in the end enjoy the music more. I hope you have a windows computer because that 30 minute time limit for Mac’s is brutal (you just have to resart HQplayer and listen for 30 more minutes, but that does become tiresome) buy a license and the 30 minute limit goes away.

Poly-sinc (except poly-sinc-ext) can convert practically any rate to any other rate, no need to worry. Some filters have conversion ratio restrictions due to technical or quality reasons.

At the moment yes. I’ve had the new RasPi for quite some time, but haven’t got time make a new build. If you can get Debian Stretch running on it, you could also use the normal Debian package of the more recent 3.x.

[quote=“John_Makela, post:37, topic:6210, full:true”]
Not so sure all audiophiles goal is transparency, otherwise I would have been very happy with any filter in HQP as they all seem to offer slightly to a lot more transparency. It still comes down to the music, and our goal, I think, is to bring the performance into our rooms as it was when recorded. [/quote]

I have heard that given as the definition of transparency.

Thanks for joining in here. What filter would you recommend to pair with the Wolfson DAC in the PS Audio Sprout?