• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

What is the cause of "digital glare"?

flipflop

Addicted to Fun and Learning
Joined
Feb 22, 2018
Messages
927
Likes
1,240
Two examples.

Recent , Aune s16- Pacific Valve 62 - Smsl su8.

Older, Adcom 575 - Eastern Electric mini max. - Mhdt labs.
The poor FR of the Adcom GCD-575 is probably the reason why you could tell them apart.
575.PNG
 

rebbiputzmaker

Major Contributor
Joined
Jan 28, 2018
Messages
1,099
Likes
463
The poor FR of the Adcom GCD-575 is probably the reason why you could tell them apart.
View attachment 19961
btw where is the measurement from?

Also had several Philips and Magavox cd players with 1541, do not know all their measurements. Still have a new single crown chip sitting in a cabinet.
 

rebbiputzmaker

Major Contributor
Joined
Jan 28, 2018
Messages
1,099
Likes
463
Thank you.

Looks worse than it actually is.

"The Adcom showed rather more frequency-response variation than the other players, being 0.7dB down at 20kHz and 2.3dB down at 4Hz. With the "Analog Frequency/Phase Contouring" (AFPC) switched in, the response was markedly altered, as shown by fig.2. The entire midrange is boosted by just over 1dB, while the treble is shelved down by 2dB, this superimposed upon the intrinsic slight HF droop. ("AFPC" seems rather a fancy label for what, to judge from the curve in fig.2, is a shaping network consisting of two resistors and a capacitor per channel.) De-emphasis was accurate, though similar to the Adcom's basic response in being down 0.4dB at 16kHz".—John Atkinson
 

andreasmaaan

Master Contributor
Forum Donor
Joined
Jun 19, 2018
Messages
6,652
Likes
9,399
Two examples.

Recent , Aune s16- Pacific Valve 62 - Smsl su8.

Older, Adcom 575 - Eastern Electric mini max. - Mhdt labs.

imo the newer ess is better than the older one.

I left out different Ifi dacs, micro and idac2, all with the chip that Thorsten uses. I tend to like them better than Ess dacs.

ymmv

Thanks.

So for example, you were able to pick a difference between Aune s16 and SMSL SU8 under controlled conditions? Or you were doing an ABC-X test with 3 DACs and were able to pick differences between all 3?

Could you give a little more info about your test setup and method please?
 

rebbiputzmaker

Major Contributor
Joined
Jan 28, 2018
Messages
1,099
Likes
463
Thanks.

So for example, you were able to pick a difference between Aune s16 and SMSL SU8 under controlled conditions? Or you were doing an ABC-X test with 3 DACs and were able to pick differences between all 3?

Could you give a little more info about your test setup and method please?
This was not one test at one time, but several. Done different times with different friends AB test blind volume matched. No, I could not reliably tell the difference between DS dacs.

Difference I am sensitive to are transients with rich harmonics. Vibes are something I use and I am very familiar with. The impact and harmonic envelope are different and noticeable to me with multi vs ds. ymmv
 

Halcyon

Member
Joined
Aug 31, 2018
Messages
14
Likes
25
There is no such thing. It is a made up thing by people who don't know how to perform controlled listening tests. If they did that, they would not hear any such thing!

Beg to differ. I've done double-blinded psychoacoustically sound (anchored) tests on this. A couple of local people who have auditorily far more accurate than I am, can actually detect similarly measuring AMPS and DACS under such conditions. And one of the description one reviewer often uses for certain DACs is "harshness" or "glare" and these units measure extremely well under AP gear (everything below threshold of audibility accodring to psychoacoustics). Still they can do it. I don't how or why.

Then again, I've done double blind for high end enthusiasts on original 44kHz/16-bit cd recordings vs 128kbit VBR mp3 and those high end enthusiasts couldn't distinguish the two from each other on their own systems (they had plenty of time).

What is the technical reason for this, I don't know.

However, the field of psychoacoustics is still advancing, esp. in regards to IMD and HD inside the ear and how those can sometimes mask or attenuate certain type of artifacts in signals. We don't know as much about hearing as we know about technical audio signal measurements, and we cannot (yet) accurately measure the subjectively filtered signal at the inner ear or auditory cortex level. Thus, we don't know yet everything we should measure in terms of audio equipment, to perfectly correlate with psychoacoustic evaluations (blinded). Therefor, many manufacturers are still forced to use also psychoacoustic evaluations as one of their design guidance tools, as they cannot only use technical measurements to guide their designs.

Just because we cannot yet measure it, doesn't mean it doesn't exist, esp. if (even only a few) people can accurately distinguish it.
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,524
Likes
37,057
Beg to differ. I've done double-blinded psychoacoustically sound (anchored) tests on this. A couple of local people who have auditorily far more accurate than I am, can actually detect similarly measuring AMPS and DACS under such conditions. And one of the description one reviewer often uses for certain DACs is "harshness" or "glare" and these units measure extremely well under AP gear (everything below threshold of audibility accodring to psychoacoustics). Still they can do it. I don't how or why.

Then again, I've done double blind for high end enthusiasts on original 44kHz/16-bit cd recordings vs 128kbit VBR mp3 and those high end enthusiasts couldn't distinguish the two from each other on their own systems (they had plenty of time).

What is the technical reason for this, I don't know.

However, the field of psychoacoustics is still advancing, esp. in regards to IMD and HD inside the ear and how those can sometimes mask or attenuate certain type of artifacts in signals. We don't know as much about hearing as we know about technical audio signal measurements, and we cannot (yet) accurately measure the subjectively filtered signal at the inner ear or auditory cortex level. Thus, we don't know yet everything we should measure in terms of audio equipment, to perfectly correlate with psychoacoustic evaluations (blinded). Therefor, many manufacturers are still forced to use also psychoacoustic evaluations as one of their design guidance tools, as they cannot only use technical measurements to guide their designs.

Just because we cannot yet measure it, doesn't mean it doesn't exist, esp. if (even only a few) people can accurately distinguish it.
So tell is about this. Which dacs were audibly different ? We're you using phones or speakers?
 

Halcyon

Member
Joined
Aug 31, 2018
Messages
14
Likes
25
So tell is about this. Which dacs were audibly different ? We're you using phones or speakers?

I'd have to go back to my notes, this was years ago (10 or so?) when I was still a hifi freelance journalist and studied psychoacoustics. I have a faint recall that one unit was a Mark Levinson and other I can't remember other than being a boutique one from Europe.

Most ABXes we did we using speakers. the MP3 vs CD originals were using whatever sound system each participant chose and I think 2 used loudspeakers only and one used loudspeakers and then headphones (he is an audio engineer by trade).
 

Pluto

Addicted to Fun and Learning
Forum Donor
Joined
Sep 2, 2018
Messages
990
Likes
1,631
Location
Harrow, UK
Digital “glare”

Way back, let's say the eighties, when an ‘outsider’ listened to studio sound, a very common remark was how ‘harsh’ it seemed. We put this down to the fact that John Doe was not used to listening to a reasonably clean top-end that had been neither mangled by the vinyl production process nor heavily attenuated by the performance of cassette tape >6 or 7kHz.

With the arrival of the CD, I suspect that huge swathes of the listening public experienced, for the very first time, the true sound of a reasonably flat response up to the typical limits of human hearing. While we are (thankfully) largely free of analogue cassette tape, I wonder how many so-called enthusiasts set their personal sonic reference point to a level defined by the sound of vinyl...
 

Dogen

Senior Member
Forum Donor
Joined
Aug 31, 2018
Messages
360
Likes
612
Location
Durham, NC USA
Funny, when I go back and read contemporaneous publications and magazine articles during the introduction of digital, I see nothing but praise and gratitude to be free of the inherent problems with vinyl. Nobody talked about digital glare or etched sound or any of the other descriptions of digital. These “symptoms” were invented years after digital was introduced to promote niche products that solved non existent problems. Now, all the reviewers say they hated early digital, but I can’t find record of many of them complaining at the time.

I like records, I like analog. But this whole “glare” notion is invented.
 

RayDunzl

Grand Contributor
Central Scrutinizer
Joined
Mar 9, 2016
Messages
13,204
Likes
16,986
Location
Riverview FL
I have some older CDs not mastered so well, early rolloff in the bass and not enough droop farther up.

Listened to one (random pick from the rack) a few days ago, can't remember what it was. Kinda screechy/thin.

On the other hand, Audio Buddy brought over a recently released 1977 concert tape (2xCD) from The Vault on Beer Saturday and it was glorious.
 

andreasmaaan

Master Contributor
Forum Donor
Joined
Jun 19, 2018
Messages
6,652
Likes
9,399
Was anyone here working in recording/mixing/mastering in the days of early digital production? Would be interesting to hear opinions of early digital effects and processing units from that early period (probably long before digital distribution formats).
 

infinitesymphony

Major Contributor
Joined
Nov 21, 2018
Messages
1,072
Likes
1,806
The people who were there can correct me if I'm wrong, but my understanding is that the Sony PCM adapters were often used for early A/D, and they were limited to 14-bit audio with a manually-adjusted DC offset (for 1st gen models). Add in the early days of filtering (brick wall), oversampling (NOS, 4x), and CDs with pre-emphasis flags that not all home CD players knew how to interpret and you certainly had a recipe for strange things to happen.
 

Guermantes

Senior Member
Joined
Feb 19, 2018
Messages
484
Likes
561
Location
Brisbane, Australia
The people who were there can correct me if I'm wrong, but my understanding is that the Sony PCM adapters were often used for early A/D, and they were limited to 14-bit audio with a manually-adjusted DC offset (for 1st gen models). Add in the early days of filtering (brick wall), oversampling (NOS, 4x), and CDs with pre-emphasis flags that not all home CD players knew how to interpret and you certainly had a recipe for strange things to happen.

I believe that by the time CDs went on the market the Sony units used for mastering were the PCM-1600/1610/1630 series which were 16 bit linear. Perhaps @restorer-john has one sequestered away . . .

I always considered "digital glare" to be part of the backlash to digital which seemed to start in the early '90s. I remember working in a hi-fi shop at the time and hearing this term being bandied about by those nostalgic for "analogue warmth". It's interesting that as soon as a technology starts to be phased out we seem to find some magical aspect about it that is lacking in the superceding one. Witness the desire to recreate the sound of analogue processes and hardware with digital plug-ins: https://www.waves.com/plugins/j37-tape#butch-vig-billy-bush-j37
 

restorer-john

Grand Contributor
Joined
Mar 1, 2018
Messages
12,587
Likes
38,285
Location
Gold Coast, Queensland, Australia
...Perhaps @restorer-john has one sequestered away . . .

No, I don't have any of the early PCM processors in my storerooms, only several DAT recorders. I had a few uMatic machines and PCM-501es at one point, but they are really no fun to keep going. They are long gone.

In 1979, Umatic was used and the NHK/Sony and the Sony (PAU-1602 and PCM-1600) were already both 16bit, at 44.1K and 44.056K respectively. Nippon Columbia (Denon) were using 14 bit umatic based at 47.25Khz. On stationary head digital recorders, by 1979, all 3rd and 4th generation machines were 16bit, most sampling at 50KHz with other selectable frequencies.

Perhaps some of the issues were caused by early sample rate conversion algorithms not being ideal.

The earliest Philips CD players used 14 bit converters (TDA-1540D) arranged in a 4xOS implementation and achieved nearly 16 bit resolution. (15.8bits IIRC), but Sony used their own 16 bit converter. Toshiba produced 14 bit converters, but they were for budget products down the track.

Pre-emphasis was handled by all first generation machines as it was part of the requirements for licensing. It was pretty much always achieved in the last analog stage triggered by an emphasis flag. As such, de-emphasis accuracy varied a little between machines, but on the whole it was a complete non-issue. Very few CDs used it. My test CDs have various emphasised and non-emphasised tracks for testing purposes. It's carried out in the digital domain mostly these days. As far as I know, all machines that carry the logo for CD must be able to correctly play emphasised discs still.
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,524
Likes
37,057
There actually was very little digital processing in the early days of Digital. ProTools let you specify some edits, and a few simple things. It then took most of an hour or more than an hour to process them so you could hear things like EQ or compression. Early on it had the name SloTools. If you didn't like the results it took the same amount of time to undo.

So nearly all processing was analog with final results being digital.
 
Last edited:

Guermantes

Senior Member
Joined
Feb 19, 2018
Messages
484
Likes
561
Location
Brisbane, Australia
No, I don't have any of the early PCM processors in my storerooms, only several DAT recorders. I had a few uMatic machines and PCM-501es at one point, but they are really no fun to keep going. They are long gone.

We had a PCM-1630 at university but no one was game-enough to touch it. The course convenor always mumbled about something needing alignment.

After putting all my USB DACs through comparative testing with tones and music, I can't say that I could hear or see anything that I would call "glare" in the ESS-based units (Topping D10 and HifimeDIY UAE23+). The PCM5122-based DAC I tested did have some changes in high frequency roll-off depending on the filter selected but that was predictable and didn't contribute any harshness to the sound. So nothing glaringly obvious.

I agree with @solderdude , this is a term to treat with suspicion. Or maybe a green pen . . .
 
Top Bottom