A few examples of the challenge with turning everything into numbers, the conclusion being, numbers are wonderful, measurements are exciting to read, but we need more than numbers, we need to know how these numbers translate into something we can relate with, for the numbers to have meaning.
We need a baseline/reference device.
Otherwise, Dynamic range of 123dB in a review with measurements, means very little, to many of us. Just says "this measures better or worse than another product". At what point do these extreme measurements become meaningless. I understand - just pile up a few more DAC's chips dual, quad, octo, and you get another few dB for the record books. where does it stop, 8 DAC's per channel, to achieve the theoretical maximum of 144 dB @ 24 bits?
But an audio chain is only as good as the weakest link.
Would be fantastic to compile this and store on a google share (or here on ASR), not just these parameters, for unbalanced headphone outputs, but for other kinds of devices, amplifiers, etc. etc.
If you have never been on a bullet train, travelling @ 250 miles an hour, or 300 miles an hour, these numbers really mean nothing, until you experience it for yourself.
If you have never seen the Mona Lisa painting in real life, or an impression thereof, any description of the painting is meaningless. But if you have seen a decent photo of it, then maybe someone standing in the Louvre, in Paris, describing the actual painting, may make some impact. Maybe.
I recall years ago, when I could not afford to buy anything, reading about gear in Sound on Sound magazine, lusting after things I could not buy, keyboards, speakers, but it was only when I could spend time with the gear, either having bought it, or heard it in a shop, then I could make some sense of what I was reading. Point being, measurements in isolation, or descriptions, without a personal reference, that we can all relate to, is pointless.
As a child in Africa, the children's books I read, had stories about snow, and caves, and Christmas, and a culture I could not experience, until I visited Europe. How do you describe snow to someone living in tropical climes, such as a Caribbean Island. It's abstract.
If you have never seen the Mona Lisa painting in real life, or an impression thereof, any description of the painting is meaningless. But if you have seen a decent photo of it, then maybe someone standing in the Louvre, in Paris, describing the actual painting, may make some impact. Maybe.
I recall years ago, when I could not afford to buy anything, reading about gear in Sound on Sound magazine, lusting after things I could not buy, keyboards, speakers, but it was only when I could spend time with the gear, either having bought it, or heard it in a shop, then I could make some sense of what I was reading. Point being, measurements in isolation, or descriptions, without a personal reference, that we can all relate to, is pointless.
As a child in Africa, the children's books I read, had stories about snow, and caves, and Christmas, and a culture I could not experience, until I visited Europe. How do you describe snow to someone living in tropical climes, such as a Caribbean Island. It's abstract.
We need a baseline/reference device.
It was the video at the link below - on Youtube, where the review of a desktop DAC, discusses the relevance or otherwise of a distortion(THD+N) measurement, which does not translate accurately to what the listener hears, that hit this home to me. Yes it is a good measurement for the purposes of comparing one device to another, but what exactly does it mean, in reality. It does not make measurements irrelevant, but measurements need a reference. So I encourage all who do reviews, or publish measurements, it's time to move on from measurements in isolation, to relevance.
And here clearly some baselines are needed, to compare with things that people can relate to. One baseline which I propose especially in the Dongle DAC world, and probably the entire universe of DAC's with a headphone amp in them, is the Apple USB-C dongle - less than $10. So ostensibly everyone interested in comparing dongles, should have one. And we compare every other Dongle DAC to this, why Apple's - cos its available everywhere, like Coca Cola, and costs about the same, everywhere, is affordable, to most. It's decent enough to NOT be a waste of money, even if we own better gear. To me it sounds decent enough, to be an OK reference/baseline. It is also a reliable product, I have not heard of any reliability issues, which speaks to its good design, manufacture, and quality control. Yes we have the European and North American variants, but that's not a problem - pick one as the standard, just decide which one that baseline should be.
When DAC's have so improved, that the Apple dongle is too far behind, to be considered a baseline, we change that baseline to a more relevant, affordable, widely available product. Nothing wrong with adding other reference products to a review of DACs, but if we have this standard, would be easier for everyone to relate to.
And here clearly some baselines are needed, to compare with things that people can relate to. One baseline which I propose especially in the Dongle DAC world, and probably the entire universe of DAC's with a headphone amp in them, is the Apple USB-C dongle - less than $10. So ostensibly everyone interested in comparing dongles, should have one. And we compare every other Dongle DAC to this, why Apple's - cos its available everywhere, like Coca Cola, and costs about the same, everywhere, is affordable, to most. It's decent enough to NOT be a waste of money, even if we own better gear. To me it sounds decent enough, to be an OK reference/baseline. It is also a reliable product, I have not heard of any reliability issues, which speaks to its good design, manufacture, and quality control. Yes we have the European and North American variants, but that's not a problem - pick one as the standard, just decide which one that baseline should be.
When DAC's have so improved, that the Apple dongle is too far behind, to be considered a baseline, we change that baseline to a more relevant, affordable, widely available product. Nothing wrong with adding other reference products to a review of DACs, but if we have this standard, would be easier for everyone to relate to.
Otherwise, Dynamic range of 123dB in a review with measurements, means very little, to many of us. Just says "this measures better or worse than another product". At what point do these extreme measurements become meaningless. I understand - just pile up a few more DAC's chips dual, quad, octo, and you get another few dB for the record books. where does it stop, 8 DAC's per channel, to achieve the theoretical maximum of 144 dB @ 24 bits?
But an audio chain is only as good as the weakest link.
At reasonable loudness levels - e.g between 70 decibels and 90 decibels, listening to speakers in a room, what's the point of a DAC which has a dynamic range of over 125 dB, when there is an amplifier between that DAC, and the speaker, that will never resolve this detail? Can't find it anymore, but read somewhere on the Internet, that power amps cannot be infinitely resolving, so as the weakest link in the chain, some of that resolution from the DAC, is discarded. Begs the question, how much of this 130dB will the speaker resolve?
As relevant would be thresholds for parameters, above which we consider - yes it's good enough, for 90% of critical listeners.
I'll give one example, I own an EMU 0404 USB, and in the specs it says - headphone crosstalk is - Stereo Crosstalk: (1kHz at -1dBFS, 600 ohm load) < -85dB. Please note this is an unbalanced headphone output. Because that was a device manufactured about 15+ years ago, I was expecting that today's devices would have improved upon this.
1. From a response by Amir - https://audiosciencereview.com/foru...digital-audio-measurements.10523/post-1983275
2. Looking at the headphone crosstalk from Julian Krause's youtube videos.
I deduced that -70dB crosstalk for a headphone output, is about good enough
As relevant would be thresholds for parameters, above which we consider - yes it's good enough, for 90% of critical listeners.
I'll give one example, I own an EMU 0404 USB, and in the specs it says - headphone crosstalk is - Stereo Crosstalk: (1kHz at -1dBFS, 600 ohm load) < -85dB. Please note this is an unbalanced headphone output. Because that was a device manufactured about 15+ years ago, I was expecting that today's devices would have improved upon this.
1. From a response by Amir - https://audiosciencereview.com/foru...digital-audio-measurements.10523/post-1983275
2. Looking at the headphone crosstalk from Julian Krause's youtube videos.
I deduced that -70dB crosstalk for a headphone output, is about good enough
Can we set benchmarks of what is good enough for other parameters, beyond which anything better will only be relevant to bats, dogs, or whales, measurable - yes, but unlikely to be relevant in a world where we already have ambient noise to contend with? In my case the air vents of my laptop probably need cleaning, cos the fan is on 99% of the time !, adding easily another 20 decibels, to the ambient room noise. !!! Gear which measures better would be nice, if only we all had anechoic chamber listening rooms! I do envy those with Apple Silicon based laptops. Nothing like some peace and quiet.....
I've set out a few benchmarks, for the unbalanced headphone outputs of a DAC(Dongle or Desktop or DAP), not sure if it's applicable to devices which are purely headphone amplifiers, without a DAC., and you are welcome to challenge them. 1st may I commend everyone who supports this forum's technology. The forum editing features are phenomenal. The values below are suggestions, somewhere to start the discussion, subject to review. And I would expect this will change over time, anyway, as manufacturing and design standards improve. Please suggest and contribute to improve this. Thanks. Most of my guestimates are based on watching Juian's videos, and other information gleaned across the web.
I've set out a few benchmarks, for the unbalanced headphone outputs of a DAC(Dongle or Desktop or DAP), not sure if it's applicable to devices which are purely headphone amplifiers, without a DAC., and you are welcome to challenge them. 1st may I commend everyone who supports this forum's technology. The forum editing features are phenomenal. The values below are suggestions, somewhere to start the discussion, subject to review. And I would expect this will change over time, anyway, as manufacturing and design standards improve. Please suggest and contribute to improve this. Thanks. Most of my guestimates are based on watching Juian's videos, and other information gleaned across the web.
Parameter | Excellent | Benchmark for "good enough" | Minimum | Comments |
---|---|---|---|---|
Frequency Response- 20Hz to 20 kHz - in dB | +/- 0.1 | +/- 0.2 | +/- 0.5 | |
Output Impedance - Ohm | < 1 | < 2.5 | < 5 | |
Power @ 16 Ohms load - mW | 200 | >100 | > 50 | |
Power @ 32 Ohms Load - mW | 250 | > 90 | > 50 | |
Power @ 150 Ohms Load - mW | 150 ? | > 80 | > 40 | |
Power @ 300 Ohms Load - mW | ? | > 80 | ? | |
Power @ 600 Ohms Load - mW | ? | ? | ? | |
Channel Balance - dB | <=0.2 | <=0.5 | <=1 | |
Crosstalk - dB | <= -80 | <= -70 | <= -60 | |
Would be fantastic to compile this and store on a google share (or here on ASR), not just these parameters, for unbalanced headphone outputs, but for other kinds of devices, amplifiers, etc. etc.