What is this?

[matthewacbroad]

First of all hello! I came across this forum reading about 1-bit DSD DACs. I hope my curious mind can get some answers as I'm very new to audio. You'll laugh at my setup but please bare with me (limited money and knowledge)

PC -> JRiver (ASIO 24-bit 96Khz @ Standard / 1024 Samples) -> Fiio X3 v1 DAC (0dB gain output) -> HD 558 OR Hyperx cloud revolver



JRiver comes with Tone test and playing 19Khz with 120 volume step on Fiio x3 v1 (120/120) I'm able to hear the tone , mind you not very loud for max volume. Now stepping back to 18Khz it's much more clear which was great until playing this song "boston - Rock & Roll Band". There's is V shape present that hits under 18Khz and somewhat distracting as hear small short tiny airy high pitch tones every 1-2 seconds which wouldn't be so bad if my mind wasn't curious!


The question i'm asking today is,

What is it?
How would one remove it without audio loss (if any) and how can it be done?

 

[andreasmaaan]

It looks like a strange artefact present in the recording. Seems there is not much musical information up there so maybe the easiest way to remove it would be with a steep low pass filter just below the frequency of the tone (maybe 17.5KHz). Of course you’d lose whatever audio information is present above that frequency, but it doesn’t seem like there’s much.

 

[matthewacbroad]

It looks like a strange artefact present in the recording. Seems there is not much musical information up there so maybe the easiest way to remove it would be with a steep low pass filter just below the frequency of the tone (maybe 17.5KHz). Of course you’d lose whatever audio information is present above that frequency, but it doesn’t seem like there’s much.

thanks, low pass filter is when you select a frequency and allows frequency under, while removing anything over?

 

[AnalogSteph]

Could be some sort of watermark, you knew, for tracking them evil piratez. Obviously the point of one is that it is not easy to remove. Steep lowpass as suggested would probably be closest. Audacity comes with a corresponding function in its effects if memory serves.

Is it just that one track? Then it's probably originating from wherever this track was originally sourced from. Looks like a "real" hi-res file in any case, so probably from original masters unless it's just a boring vinyl rip (dB-scaled amplitude would tell that pretty clearly assuming the lower limit is adequate).

BTW, that's some enviable hearing. Mine is quickly going south above 13 kHz these days, and I'm not even old.

 

[andreasmaaan]

thanks, low pass filter is when you select a frequency and allows frequency under, while removing anything over?

Exactly. You could do it in audacity, then export the audio as a wave file.

Btw, nothing funny about your setup. All very decent quality stuff.

 

[andreasmaaan]

Could be some sort of watermark, you knew, for tracking them evil piratez. Obviously the point of one is that it is not easy to remove. Steep lowpass as suggested would probably be closest. Audacity comes with a corresponding function in its effects if memory serves.

Is it just that one track? Then it's probably originating from wherever this track was originally sourced from. Looks like a "real" hi-res file in any case, so probably from original masters unless it's just a boring vinyl rip (dB-scaled amplitude would tell that pretty clearly assuming the lower limit is adequate).

Doesn’t look like a watermark to me at all. A watermark would be embedded in the same range of frequencies as the music and nowhere near as obvious. It’s something weird and probably unintentional.

Just check another track from a different recording though to make sure it’s not a software problem on your end.

 

[Krunok]

Oddly enough that seems to be part of the recording. You may try using Low pass filter in Audacity.

https://manual.audacityteam.org/man/low_pass_filter.html

 

[Krunok]

Exactly. You could do it in audacity, then export the audio as a wave file.

LOOL

 

[Krunok]

This is how it looks in Audacity..

 

[matthewacbroad]

yes out of the album this song is the only with that artifact. I never came across it before and picked it up when turing up the volume max on my DAC. In Acceptable volumes say 60/120 Im unable to hear the artifact and limited to 16-17khz (again with tone test in Jriver) but range is increased with volume for me. When a good song comes on I cant help but turn it up

Thank you

 

[Krunok]

yes out of the album this song is the only with that artifact. I never came across it before and picked it up when turing up the volume max on my DAC. In Acceptable volumes say 60/120 Im unable to hear the artifact and limited to 16-17khz (again with tone test in Jriver) but range is increased with volume for me. When a good song comes on I cant help but turn it up

Thank you

No problem. Btw, you have really good hearing.

 

[andreasmaaan]

@matthewacbroad I would find the lower frequency limit of the artefact and use a steep (say 48dB/octave) low pass filter in audacity to remove it. Might be 16K or 17K, you'll have to zoom in on the artefact to find exactly at what frequency it occurs, apply the filter just below that frequency, and then check to see that it's (mostly) gone. Given that you can only hear it at high SPL as it is, you probably don't need to completely remove it, but just remove enough of it that what remains is masked by the rest of the signal.

Btw, you have really good hearing.

Yes

 

[Krunok]

@matthewacbroad I would find the lower frequency limit of the artefact and use a steep (say 48dB/octave) low pass filter in audacity to remove it. Might be 16K or 17K, you'll have to zoom in on the artefact to find exactly at what frequency it occurs, apply the filter just below that frequency, and then check to see that it's (mostly) gone. Given that you can only hear it at high SPL as it is, you probably don't need to completely remove it, but just remove enough of it that what remains is masked by the rest of the signal.

The artifact starts sharply at exactly 20000 Hz.

 

[andreasmaaan]

The artifact starts sharply at exactly 20000 Hz.

Oh I missed your post.

In that case @matthewacbroad has insanely good hearing!

 

[Krunok]

Oh I missed your post.

In that case @matthewacbroad has insanely good hearing!

Yep, indeed he does.

Btw, peak of the artifact is at -57dB (see cursor data at Audacity spectrum plot).

 

[matthewacbroad]

thanks for recommended actions.

When I enable +6dB on headphone output inside Fiio x3 OS and max volume 120/120 than play tone test of 20khz, Im able to hear it but this is ear bleeding with lower frequency.

Its cool im able to hear that high but I find it hard to place in real world use. The way we hear 500hz to 15khz (guessing) is what our ears have most detail with or seems that way. Least to me it isnt worth high volumes & damage ears in return for tiny 18-20khz spots in music.

Could one adjust 17-20khz in EQ to bring up those frequency in lower volumes?

Again noob here sorry for questions my mind is just so curious about audio

 

[andreasmaaan]

Looking at @Krunok's graph, I'd actually try a notch filter at 21KHz with Q of about 1.5 or 1.

 

[andreasmaaan]

thanks for recommended actions.

When I enable +6dB on headphone output inside Fiio x3 OS and max volume 120/120 than play tone test of 20khz, Im able to hear it but this is ear bleeding with lower frequency.

Its cool im able to hear that high but I find it hard to place in real world use. The way we hear 500hz to 15khz (guessing) is what our ears have most detail with or seems that way. Least to me it isnt worth high volumes & damage ears in return for tiny 18-20khz spots in music.

Could one adjust 17-20khz in EQ to bring up those frequency in lower volumes?

Again noob here sorry for questions my mind is just so curious about audio

Just to clarify, can you hear this artefact when playing back the track at high SPL?

If not, I wouldn't bother correcting it. If you can hear it, try what I suggested in post #17.

 

[matthewacbroad]

Just to clarify, can you hear this artefact when playing back the track at high SPL?

If not, I wouldn't bother correcting it. If you can hear it, try what I suggested in post #17.

spl?

I never would of notice anything if i didnt hear it. Ive always use audacity but never to look at freqency (more to mess around with effects like reverb and compressor because I have limited knowledge about this) I found out what a spectrograph is when reading about 1bit dsd files and connected the dots when it struck me that song was odd out of the rest

again this is at high volume where once headphones come off I hear staic background noise like you do after a concert not everyday use

I just wanted to know why thats there and if it was possible to remove it.

 

[andreasmaaan]

spl?

I never would of notice anything if i didnt hear it. Ive always use audacity but never to look at freqency (more to mess around with effects like reverb and compressor because I have limited knowledge about this) I found out what a spectrograph is when reading about 1bit dsd files and connected the dots when it struck me that song was odd out of the rest

again this is at high volume where once headphones come off I hear staic background noise like you do after a concert not everyday use

I just wanted to know why thats there and if it was possible to remove it.

SPL = sound pressure level (i.e. "volume")

Yeh, that's what I thought - that you could actually hear it when listening to the recording. Just double-checking because it's the kind of thing that most adults (and probably many children) couldn't hear. No doubt the engineers who recorded, mixed and mastered the track couldn't hear it, otherwise it wouldn't be there in the first place.

In that case I'd try my suggestion in post #17.