tuga
Legal Alien
Must have been the curtains…
If the Quad philosophy is that an amplifier should be a straight wire with gain....
- Thread starter Ianp
- Start date
les24preludes
pfm Member
I bought a Topping DAC on the basis of glowing reviews that the distortion was state of the art low. It sounded rubbish to everyone who listened to it. Whatever they were measuring had no relation to the actual sound quality. Moral of the story, as we all should know, is trust your ears.
misterdog
Not the canine kind
There is far more to measured transparency than just THD+N, though this is usually a good indicator and starting point.
The DAC 1 is an old design which actually measures quite poorly, my cheap Topping DAC has SINAD (signal, noise and distortion) of 120 dB, where your former DAC1 has 104dB.
However when you look at linearity for example we see this for the DAC 1 against the measures for 3 other DAC's.
The measured IMD is also the worst of the measured bunch, though note the strange 'hump' from the ESS DAC chip on the Topping DAC.
misterdog
Not the canine kind
Post which model please, not all Topping DAC's were state of the art as can be seen from the IMD hump posted above.
As previously posted (from 2018) things have progressed greatly, in terms of measured accuracy.
Though on a subjective level, near zero distortion sounds fabulous to me, and others.
How should a straight wire with gain, sound though...
Peter Walker was measuring his equipment back in the 1950's and 60's and trying to improve both it's measured and 'sound' qualities.
Electronic engineers use measured response as the first port of call.
awkwardbydesign
Officially Awesome
That you didn't see.
All sound is distorted in some way...The distortions which come from electronic components, and their design.
Distortion is a sound.
darrenyeats
pfm Member
First, to be fair to the DAC1, ASR said the linearity was quite a lot better via XLR. Most unfortunate Amir mislaid the graph!There is far more to measured transparency than just THD+N, though this is usually a good indicator and starting point.
The DAC 1 is an old design which actually measures quite poorly, my cheap Topping DAC has SINAD (signal, noise and distortion) of 120 dB, where your former DAC1 has 104dB.
However when you look at linearity for example we see this for the DAC 1 against the measures for 3 other DAC's.
The measured IMD is also the worst of the measured bunch, though note the strange 'hump' from the ESS DAC chip on the Topping DAC.
Second, I speak of what we were told at the time. The DAC1 in terms of XLR measurements was excellent and a contemporary giant killer. *That* was a fact and remains so. The problem is that I thought I was done because they said it was even better than transparent. Sadly, I'm old enough to remember.
The numbers attached to the story changed, but the story hasn't - that's my point.
Now maybe it's true with the new numbers. I'm not sure. All I'm saying is "Fool me once, shame on you, fool me twice, shame on me".
Enjoy your amp, to be clear, I honestly believe you that it sounds great!
Last edited:
John Phillips
pfm Member
One of the impressions I have (which I can't prove) is that the combination of a well-made recording made with modern production kit and listened to on modern reproduction kit produces a quieter background with more low-level detail than I have previously experienced. Is that "transparency"? I assume it is, in part at least.
I cannot say what parts of the end-end process are responsible (and I don't exclude my ear-brain system). But your point resonates here. I also wonder to what extent the increased resolution/transparency of the modern DAC is a part of my impression.
Of course when listening to 1950s opera recordings their background noise dominates modern kit. I do wonder from reading the occasional "how many angels can dance on the head of a pin?" argument whether anyone could possibly enjoy them - but I do. For sure I am interested in the technology and its developing performance, but things like the 1953 Clemens Krauss Wagner Ring cycle ground my sense of the difference between "is it audible?" and "does it matter?" Even so I am always happy to see and enjoy measurable technical progress on the transparency front.
sonddek
Trade: SUPATRAC
Jim Audiomisc
pfm Member
Only to the extent that some people *prefer* some kinds of distortion, depending on them and the nature of the music.
Jim Audiomisc
pfm Member
There is far more to measured transparency than just THD+N, though this is usually a good indicator and starting point.
The DAC 1 is an old design which actually measures quite poorly, my cheap Topping DAC has SINAD (signal, noise and distortion) of 120 dB, where your former DAC1 has 104dB.
However when you look at linearity for example we see this for the DAC 1 against the measures for 3 other DAC's.
The measured IMD is also the worst of the measured bunch, though note the strange 'hump' from the ESS DAC chip on the Topping DAC.
The snag with plots like the above is that well recorded audio will be dithered and have a real-at-the-mic noise level that can dither away the 'very low signal' nonlinearity shown by a test result. Similar argument to the one about mag domains on analogue tape, etc, but at a lower level. The other end of that is how small an audio signal may be before you can't hear it anyway.
les24preludes
pfm Member
I think a better way of putting this would be to say that it's a question of the whole spectrum of harmonics. Second order may add some kind of euphonic effect, but odd order distortions are more nasty.
This was pointed out way back in time when evaluating why EMT cartridges sounded so good - it was partly the harmonic spectrum. I think it was some French guy who did the tests.
Jim Audiomisc
pfm Member
If you pick out almost any aspect and totally ignore all other facets of reality, that may well happen.
The trick is to ensure defects in kit are small enough not to be a problem when used to record or play real recordings that come from things like mics that have their own noise, distortion, etc.
wulbert
pfm Member
Certainly not by me. When people talk about "distortion", I always think of my electric guitar's distortion pedal. If I can't hear that type of overdriven rasping sound on my system, I'll assume it has no distortion.
People always talk about distortion but it's never clear to a simpleton like me what type of noise it is, what it sounds like, or even if humans can hear it. So I tend to just ignore it.
John Phillips
pfm Member
The question of "what level is audible?" is not well understood at all AIUI. I have seen it written in published technical texts that the only design target with any justification is zero.
There have been tests on the audibility of Total Harmonic Distortion (THD) but for music reproduction the results of are not that relevant. That's because underlying a system's THD measurement is non-linearity in the system's transfer function. THD is a symptom - not the underlying problem. If you hit the underlying problem with a broadband signal (like music) this also produces Intermodulation Distortion (IMD). It has been known for decades that total IMD in that situation is 20 dB higher than THD (x10 in voltage terms).
I have noticed that Wolfgang Klippel has published quite a lot of material on the subject of distortion, including IMD, produced by various non-linearities in loudspeakers. Some of that includes assessment of how annoying distortion is for each non-linearity. However I have only glanced at that material so I don't know how far the understanding has got in that case.
Jim Audiomisc
pfm Member
As per the above: THD isn't a good measure of the audibility of a nonlinear change. The same THD value can arise from a variety of actual alterations. Some forms of distortion are less noticable than others. Some may also make a sound seem *better* to the listener
Sue Pertwee-Tyr
Accuphase all the way down
I've recently been made aware of a 2023 paper by Kunchur which has some very interesting things to say about the human auditory system and implications for high end audio systems:
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4437822
TL;DR: timing is more important that frequency, and we are one or perhaps two orders of magnitude more sensitive to timing errors than previously recognised. System response times and the ability to reproduce transients (including transient frequencies well above the audible range) are more important for the perception of music than frequency response. Old people, whose hearing may be 2 octaves down on ideal hearing (ie, hearing little or nothing >4.5kHz) are still able to perceive differences in the reproduction of transients. Also, system measurements (including cable measurements) may not capture sufficient information about rise and fall times.
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4437822
TL;DR: timing is more important that frequency, and we are one or perhaps two orders of magnitude more sensitive to timing errors than previously recognised. System response times and the ability to reproduce transients (including transient frequencies well above the audible range) are more important for the perception of music than frequency response. Old people, whose hearing may be 2 octaves down on ideal hearing (ie, hearing little or nothing >4.5kHz) are still able to perceive differences in the reproduction of transients. Also, system measurements (including cable measurements) may not capture sufficient information about rise and fall times.
awkwardbydesign
Officially Awesome
This is taken from a post on Vinyl Engine some years ago. A poster named desktop, who used to work for Disney designing sound systems.
"When my hearing was last tested there was a noise floor calibration test done as part of it. But I asked the tech to continue with quieter and quieter signals, until they were much quieter than the noise floor. I could still pick out signals @-10db below the noise floor. Noise floors are complex and audio tones are not, so detecting the tones was easy for me. The tech herself tried to hear these tones that far below the noise floor and wasn't able to do it. I applaud Whitneyville because it sounds like he has preserved his hearing as well as possible (considering he is a shooting enthusiast). But since I have not ever heard that it is physically impossible for anyone in the world to ever use their ears to detect frequencies above 35KHz, I obviously need to go back to school on that subject."