DAC filters?

[olds1959special]

Sounds plausible, due to the variable impedance of DT880, lows might be boosted by a high output impedanceamp, balancing the peaks in treble. Despite the more natural presentation created by a bass boost however, the peaks in highs will still be there and still will be fatiguing in my experience.

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I have no problem with the treble on my DT-880 - 600's, and also have DT-990 - 600's I like with this amp too, which have even more treble. I have found a tube buffer to be the answer to alleviate fatigue for me. I now use linear phase fast roll-off for the DAC filter.

 

[IAtaman]

I have no problem with the treble on my DT-880 - 600's, and also have DT-990 - 600's I like with this amp too, which have even more treble. I have found a tube buffer to be the answer to alleviate fatigue for me. I now use linear phase fast roll-off for the DAC filter.

What I hear you are saying effectively is that you don't mind +4dB at 5-8KHz range, but it's the 0.5dB at 20KHz that was bothering you.

 

[ejr]

I disagree with comments to the effect that there is no difference between DAC filters. The fact that some people can't hear it doesn't mean that it isn't there or that those who can won't find it bothersome. Everyone's hearing is potentially different.

I have always been able to hear higher frequencies than most people. When I was a kid, I could hear dog whistles (even the one at the end of Sargent Pepper on the original LP and the early CD release that included it.) I lost some hearing due to injury, when I was in my 20s, and more in my old age. All in the high range, but not continuous or consistant in the latter case (it varies a lot from day to day) which appears to be hereditary.

That said, I have a Loxjie D30 and D40. They both have the same DAC chip (but the D40, for which I used the balanced outputs, has two of them). On the D40, I find that Filter 1 generally has the sound that I like the best. It's the most clear and analytical to me, but it does seem to have boosted the upper treble range and this can be shrill or have a ringing effect on some recordings. So, I have started playing with Filter 2 as well and trying the different Sound Color settings on both of them. (I read something about Filter 3 quite a while ago that convinced me that I shouldn't use it, but I don't remember the reason.)

So far, to my ears, the settings that lessen the shrillness kill too much of the high range or greatly reduce the volume of the mid-range (which sounds even worse). It's hard for me tell, though because (as previously stated) what I hear varies from recording to recording and from day to day. It would help if anyone who knows exactly what each filter and sound color does (or is supposed to do) would explain that here, for us to use as a starting point.

Thanks.

 

[antcollinet]

I disagree with comments to the effect that there is no difference between DAC filters.

I'm not sure people are saying that.

Some of the slower filters start to roll off the response from around 10Khz, and that is quite likely to be audible in an ABX test for people with good hearing above that frequency. It's not going to be a huge "night and day" difference though.

However, that type of filter is essentially broken by design. If you are comparing two devices with filters with fast rolloff above 20IHz and good attenuation (typical of the default filter used on competent DAC designs) then you are exceedingly unlikely (to the point of impossibility) to hear the difference.

 

[markanini]

Which test signals would make the differences between the filter options maximally detectable to human ears?

 

[staticV3]

Which test signals would make the differences between the filter options maximally detectable to human ears?

White noise high-passed at ~15-20kHz, would be my guess.

 

[markanini]

White noise high-passed at ~15-20kHz, would be my guess.

How did you determine that it's not a transient signal, or sharp pulsing signal?

 

[staticV3]

How did you determine that it's not a transient signal, or sharp pulsing signal?

Because continuous signals are easier to A/B

 

[KSTR]

Which test signals would make the differences between the filter options maximally detectable to human ears?

White Noise (doesn't need to be high-pass filtered) is good for spotting the general spectral change, especially when comparing a NOS or "slow rolloff" filter vs. "sharp rolloff".

Single-sample pulses can also be used and might expose any ringing (to young and trained ears only, IMHO). The spectral effect can be heard as well, because a pulse's spectrum is white, too. The pulse will appear to be a bit softer.

A further possibility are steady-state sine very close to fs/2. These signals are hard to use because one must still be able to hear a 22kHz sine clearly as a tone. With non-perfect filters one can hear a beating, the volume of the sine swells up and down. Say, you are 10Hz below fs/2, then with an imperfect filter you will get an image at fs/2 + 10Hz with almost the same level. These two closely spaced tones produce a 20Hz beat frequency, that is, an apparent fs/2 sine is pulsating up and down in volume 20 times per second, which sounds rough and gritty.
This could well be (a part of) the mechanism behind the notion that filterless NOS DACs tend to emphasize transients despite the lower steady-state volume in the top octave... and that is not exactly intuitive.