DAC "reconstruction" filters

[Warszawa]

Currently enjoying @batteredhaggis old Luxman DA-06 and I am somewhat baffled by the three filter options.

I can understand the filters on the likes of the Qutest or RME that adjust the audible frequency response by rolling off the treble to taste, but what's this interpolation business? I believe the Auralic Vega has something similar but I couldn't for the life of me hear a difference, in the short time I had one a few years back.

Obviously once I'm used to the DAC I will try all three and pick a preference (I'll need an extra pair of hands of that as there's no remote) but first of all could someone explain to me in plain English what they're doing and how they should effect the sound? If your answer is "they won't make an audible difference" (*cough* Keith), then could you explain why the designers implemented the feature in the first place.

Full jargon at the link below.

Cheers.

https://www.stereophile.com/content/luxman-da-06-da-processor-measurements 

 

[Fourlegs]

Listen to them. If you don’t hear any difference then I suggest just picking the default one. If you do hear a difference then pick the one you prefer. 

Job done. 

 

[tuga]

Currently enjoying @batteredhaggis old Luxman DA-06 and I am somewhat baffled by the three filter options.

I can understand the filters on the likes of the Qutest or RME that adjust the audible frequency response by rolling off the treble to taste, but what's this interpolation business? I believe the Auralic Vega has something similar but I couldn't for the life of me hear a difference, in the short time I had one a few years back.

Obviously once I'm used to the DAC I will try all three and pick a preference (I'll need an extra pair of hands of that as there's no remote) but first of all could someone explain to me in plain English what they're doing and how they should effect the sound? If your answer is "they won't make an audible difference" (*cough* Keith), then could you explain why the designers implemented the feature in the first place.

Full jargon at the link below.

Cheers.

https://www.stereophile.com/content/luxman-da-06-da-processor-measurements 

There is no perfect digital filter so manufacturers (i.e. Chord, RME) are now offering different filters each with its own advantages and downsides (this has been discussed at length in one of the RME/Chord threads).

 

[MartinC]

I think this is worth a read:

http://archimago.blogspot.com/search?q=filter+myth

I also just quickly found the following on the same site, although I haven't read it yet:

http://archimago.blogspot.com/2016/07/musings-digital-interpolation-filters.html

 

[tuga]

I think this is worth a read:

http://archimago.blogspot.com/search?q=filter+myth

I also just quickly found the following on the same site, although I haven't read it yet:

http://archimago.blogspot.com/2016/07/musings-digital-interpolation-filters.html

This is all the OP needs:

Linear-phase slow roll-off: mild top-end attenuation, short symmetric-ringing (Luxman filter 1)

.

Minimum-phase sharp roll-off: no top-end attenuation, longer post-ringing, phase totation above 1?kHz (Luxman filter 2)

.

Linear-phase sharp roll-off: no top-end attenuation, longer post-ringing (Luxman filter 3)

.

.

.

I use the track "The Astounding Eyes Of Rita" to compare filters. My file player/processor has about a dozen different ones.

 

[batteredhaggis]

Listen to them. If you don’t hear any difference then I suggest just picking the default one

Funnily enough...

 

[Warszawa]

Thanks all. I'll give the Archimago site a read. Obviously I'll ultimately trust my ears.

 

[Warszawa]

This is all the OP needs:

Could you point me to the page where you found these please?

 

[tuga]

Could you point me to the page where you found these please?

I quote a message with the link.

Trade-off of less ringing is a bit of aliasing and a bit of top-end roll-off by the way.

 

[Millennium]

Audiolab M-DAC is brilliant. I'm using it in XLR at the moment. The RCA is a little worse on the bass. Amaze.

If anyone has this dac (mine was s/h with an electrosound psu) can you suggest perhaps which filter is best? I am a newb and I'm not sure any of them are correct (going by the manual!).

On topic no dsp no filtered?

 

[dave]

Highly simplified Dave version. The sample rate is not high enough on CDs etc (unfortunately) to reproduce the high frequencies sensibly. Mankind tries to fix this flaw after the effect with different filters. Some work better for some recordings, some better for others. Highly subjective and a bit of a cludge. Was hopeful mqa could have fixed it but not convinced anymore. Open minded at present.

 

[Shadders]

Was hopeful mqa could have fixed it but not convinced anymore. Open minded at present.

Hi,

You do not need MQA to solve the frequency issue - any higher sampling rate system (DVD Audio, Blu-ray audio, downloads) will solve. MQA does not solve the CD problem of limited bandwidth. MQA is worse at high frequencies than any higher resolution file which implements LPCM.

Regards,

Shadders.

 

[Warszawa]

I quote a message with the link.

Trade-off of less ringing is a bit of aliasing and a bit of top-end roll-off by the way.

Oh I see. I thought there was a direct reference to the Luxman somewhere but these filters effectively do the same thing in different DACs. Gotcha.

 

[tuga]

Oh I see. I thought there was a direct reference to the Luxman somewhere but these filters effectively do the same thing in different DACs. Gotcha.

The Stereophile measurements you linked show the measurements of your DAC but these are put together in a way that makes visualisation easier.

These filters were made using iZotope, a tool which allows the user to design whatever filter he fancies.

 

[Metatron]

Roll-off always comes across like a negative thing if it's before 20khz.

Thing is, most of us can no longer hear that high. So just in case anybody rules out a filter because it rolls-off early before 20kHz... check to see what frequency you can still hear up to, and the filter rolls off at or after that frequency, give it a whirl.

 

[Warszawa]

Roll-off always comes across like a negative thing if it's before 20khz.

Thing is, most of us can no longer hear that high. So just in case anybody rules out a filter because it rolls-off early before 20kHz... check to see what frequency you can still hear up to, and the filter rolls off at or after that frequency, give it a whirl.

Very true. I can understand how roll off before 20KHz effects the sound, it's the roll off beyond that that had me confused.

 

[dave]

The ear works in the time domain as well and 44.1kHz and reconstruction filters make a mess of that.

 

[PuritéAudio]

Perhaps read Archimago’s post that Martin linked to earlier or any digital ‘primer’ Monty Montgomery’s are very informative.

Keith

 

[tuga]

Very true. I can understand how roll off before 20KHz effects the sound, it's the roll off beyond that that had me confused.

A slower roll-off reduces ringing but is not as effective at filtering out the aliases:

P-1 (normal FIR filter)

P-3 (high attenuation FIR filter)

.

P-1 (normal FIR filter)

P-3 (high attenuation FIR filter)