Mark, I do mostly Vacuum Tube Power amps, and an occasional line amp without completing the build due to designing it for the fun of the design.
Consequently, I am interested in distortion at high levels.
Many of the people (including myself) who design amps post detailed information about the performance of the amps including Frequency Response, distortion profiles (not just THD, but plots of distortion vs frequency at various output levels and driven frequencies).
This is in the Lounge, and I have not seen much posted from you previously (this may be from my mostly posting in the tube threads).
The Lounge pulls from all of the other threads when a thread wanders from the main emphasis of the posted thread area, or is in an area which is questionable with regards to accepted theory for engineering or Physics (QM majik stickers, cable lifters , etc).
So, I'm not sure what your slant is on testing.
However that said, I suggest you start a thread in the appropriate section (Line sources, Digital sources, whatever) to propose testing methodologies and equipment for evaluating DACs.
I think this may be a more productive way of achieving your goal of advancing testing methodologies and standards than posting in the Lounge.
Consequently, I am interested in distortion at high levels.
Many of the people (including myself) who design amps post detailed information about the performance of the amps including Frequency Response, distortion profiles (not just THD, but plots of distortion vs frequency at various output levels and driven frequencies).
This is in the Lounge, and I have not seen much posted from you previously (this may be from my mostly posting in the tube threads).
The Lounge pulls from all of the other threads when a thread wanders from the main emphasis of the posted thread area, or is in an area which is questionable with regards to accepted theory for engineering or Physics (QM majik stickers, cable lifters , etc).
So, I'm not sure what your slant is on testing.
However that said, I suggest you start a thread in the appropriate section (Line sources, Digital sources, whatever) to propose testing methodologies and equipment for evaluating DACs.
I think this may be a more productive way of achieving your goal of advancing testing methodologies and standards than posting in the Lounge.
Because the majority of these projects are not built by competent engineers? This is DIYaudio after all.
It is all too easy to devalue the accumulated skill and experience of a lifetime. I watch my son struggle to solve problems that I consider trivial - not because of a lack of tools but because he lacks the trained/learned logical analysis that divides and conquers (usually - we have bad days 🙂)
I suspect most builders are relieved at the end of a project that they have NOT burnt the house down or electrocuted the cat and there is SOME sound coming out of the speakers again. After all that effort it has to sound good. Why risk it all with 'boring' measurements?
Regarding measurements: My current project (proceeding at a glacial pace) is a 12-channel master level control using TI PGA2311. I want it to "sound" as objectively transparent as possible, so for me that means measuring & testing as carefully and accurately as I'm able. I can't afford or justify the cost of lab-grade test equipment, but I believe I can get a pretty good look at things with a decent 24/96 sound card. Lastly, I may also attempt some ABX testing if I can figure out how to do it correctly with this particular piece. I will post results here, for whatever they might be worth.
Yes.....if one accepts touted hearing limits and sensitivities thresholds.
I would accept that as an informal but pretty good proof of repeatable audibility.
(1) ie, are they actually inappropriate for defining audible very small errors ? (due to noises, distortions, modulations and intermodulations).
(2) arguably next to nobody has 20/20k hearing, which means less information to detect and process.
The distortions and noises that subjectively matter the most are in our speech band (300Hz-4k give or take) and that is what the impaired listener is left with (give or take), so it could be argued that the impaired listener is the better listener for this band of interest (300Hz - 4k).
For reproduced (and by definition distorted) musical performances, it so happens that most of the fundamentals 'action' happens in this band with the lower order harmonic distortion products falling into this band also.
In the case of TheGimp, his hearing aids are adding another 'layer' of band limiting, and another layer of distortions and noises....iow wearables Cordell's distortion magnifier, and in the case of naturally (or caused) declining hearing HF response and without hearing aids the same could still be said to be true.
In the context of variable line quality telephone conversations, I have alwas found it quite remarkable that the speakers voice can be recognised and information reliably conveyed despite the worst of worst sound quality.
There was recent discussion regarding listening modes....ie typically musicians ignore noise and hear the notes only, the critical listener the sounds, the live sound operator is listening through the sound for noises, the submarine passive sonar operator is listening through the noises for information.
Through training involving thousands of AB tests using my filters (and others) I have learned to listen through the signal and note the noises, and the natures of the noises.
Ferrite core inductors are noisy, ferrite speaker magnets are noisy and the nature of these noises can be changed at will, etc, etc...
I can also kick back and just enjoy the music for what it is despite the distortions and noises that I now readily hear and identify when I want to.
Good.
We have all read of products that claim interesting properties and have gained sensible positive reviews BUT with nonsensical explanations and nonsensical pricings.
The explanations and the pricings do not eliminate that at least some of these products do have beneficial effect....their perceived value is another subject.
Dan.
-quote-
I sank $2000 of my own money into the DAC2 HGC last December, so I subjectively wanted it to sound better than everything else. Tests have shown that it doesn't. I was surprised, but, having been personally involved in the evaluation and believing in the integrity of what we set up, I rationally accept the findings
-unquote-
from:
Audiophile PC Sound - The Real Cost of Hi-Fi - Tom’s Hardware
Mankind has been made aware of this already 3 years ago. Yet, I only recently spent serious Euro's on an RME ADI Pro DAC. I am convinced it sounds better than every DAC I owned before. Or am I?
I sank $2000 of my own money into the DAC2 HGC last December, so I subjectively wanted it to sound better than everything else. Tests have shown that it doesn't. I was surprised, but, having been personally involved in the evaluation and believing in the integrity of what we set up, I rationally accept the findings
-unquote-
from:
Audiophile PC Sound - The Real Cost of Hi-Fi - Tom’s Hardware
Mankind has been made aware of this already 3 years ago. Yet, I only recently spent serious Euro's on an RME ADI Pro DAC. I am convinced it sounds better than every DAC I owned before. Or am I?
I spent 63 euros for a Behringer U-Phoria UMC202HD.
I am also convinced it sounds better than any interface I had before.
I am also convinced it sounds better than any interface I had before.
In terms of metric, 1.25^2mm changed to 2.08. I did notice the difference years ago, but did not find a second one for the other channel. Length is 2M.
In the past, the difference was not as significant because of other factors. This time I was using a DAC with much lower harmonic distortion, FIR filter compensation for the speakers/amp.
Some of this I still have yet to find a way to measure the differences, but I have changed my default USB cable to a Tripp Lite 3ft cable because I did find it gave lower harmonics in loop back testing. One can argue that the difference is meaningless, and the perceived dynamics is reduced, but after consideration, in correctly reveals the limits of a small system, and the other aspects does present a more realistic playback, so I made the switch.
These are low cost changes, so the change was really well worth it. Cheap snake oil?
Anyone can find some way to do their own blind testing. In same cases it may require building a switch box for somebody else to operate, or something of a similar nature.
The important things when doing that is to make sure that you don't know what you are listening to, that you are listening to the exact same audio sample, and that you are listening for the exact same attributes of sound regardless of whatever DUT you think you make be hearing. Looping a short sound sample can help a lot, IME.
Also, I think there are reasons to suspect where people tend to run into trouble with sighted testing has at least in part to do with comparing certain attributes or characteristics of a sound sample when listening to one DUT with different attributes of sound when listening to another DUT. That is, if DUT #1 has more HF extension, and DUT #2 has more depth of soundfield, that amounts to comparing apples to oranges in terms of attributes listened for. When listening is sighted, one can focus attention on apple or orange attributes and those things can stand out as different because of focused attention differences, more so than DUT differences.
In my case if I start to feel like I know which DUT is which, sometimes I will scramble the samples to make them completely unknown again, and see if I can differentiate them again. I do that to avoid being influenced by hunches, and to make sure I am only listening and not trying to confirm a hunch as to which DUT is which.
The important things when doing that is to make sure that you don't know what you are listening to, that you are listening to the exact same audio sample, and that you are listening for the exact same attributes of sound regardless of whatever DUT you think you make be hearing. Looping a short sound sample can help a lot, IME.
Also, I think there are reasons to suspect where people tend to run into trouble with sighted testing has at least in part to do with comparing certain attributes or characteristics of a sound sample when listening to one DUT with different attributes of sound when listening to another DUT. That is, if DUT #1 has more HF extension, and DUT #2 has more depth of soundfield, that amounts to comparing apples to oranges in terms of attributes listened for. When listening is sighted, one can focus attention on apple or orange attributes and those things can stand out as different because of focused attention differences, more so than DUT differences.
In my case if I start to feel like I know which DUT is which, sometimes I will scramble the samples to make them completely unknown again, and see if I can differentiate them again. I do that to avoid being influenced by hunches, and to make sure I am only listening and not trying to confirm a hunch as to which DUT is which.
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Regarding the newest, most expensive DAC being perceived at the best ever, maybe it is for you. The technology keeps improving as measured performance data shows.
Last time I changed DACs, from a DAC-1 to a DAC-3, I found they sounded different. The new one sounded a little more detailed. I think it probably sounded a little "better" too, but the impression of it sounding different and more detailed stood out more to me.
Last time I changed DACs, from a DAC-1 to a DAC-3, I found they sounded different. The new one sounded a little more detailed. I think it probably sounded a little "better" too, but the impression of it sounding different and more detailed stood out more to me.
Okay, but if my DAC did that i would look for a new DAC and not be satisfied with a cable swap, which would amount to a kludge bandaid treatment, IMHO. (Unless maybe the cable was clearly broken/defective. I would especially avoid expensive audiophile cables which should not be needed.)
EDIT: In some cases small gauge power conductors in USB cables, especially for longer cables, can result in enough voltage drop to affect reliable USB device operation. In such cases using cables with heavier gauge power conductors would not be unreasonable.
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Mark, I have tried standard USB cables or my modified USB cables on a number of DACs and the result is the same ie the two cables sound different regardless of which DAC is connected and there is a sameness for the standard cable, ditto the custom cable.
In all the DACs the USB transceiver stage is datasheet/evaluation board implementation, so presumably reasonably optimal.
Dan.
Dan, What DACs are we talking about? Can you give us a short list?
Are they USB powered DACs?
Do they also support SPDIF? If so, do you notice similar issues with SPDIF?
If we are talking DACs that don't clean up incoming data clocking, then I would still get a better DAC that does.
Regarding evaluation boards, I'm not sure they are optimal. They often seem to be examples of fairly minimal designs. They may try to make selecting a particular DAC part look easy and attractive.''
EDIT: I should probably also ask if you have someone else switch out the cables for you while you take the speakers in the next room to listen? You may say you don't need to do that, but if we were looking at this at the same place and time together, I would insist we take turns listening or swapping, but not both at the same time. Trust, but verify. We are all human.
Are they USB powered DACs?
Do they also support SPDIF? If so, do you notice similar issues with SPDIF?
If we are talking DACs that don't clean up incoming data clocking, then I would still get a better DAC that does.
Regarding evaluation boards, I'm not sure they are optimal. They often seem to be examples of fairly minimal designs. They may try to make selecting a particular DAC part look easy and attractive.''
EDIT: I should probably also ask if you have someone else switch out the cables for you while you take the speakers in the next room to listen? You may say you don't need to do that, but if we were looking at this at the same place and time together, I would insist we take turns listening or swapping, but not both at the same time. Trust, but verify. We are all human.
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I guess not. This was published 36yr. ago, a passable instrumentation amplifier could be built out of three op-amps and some resistors.
Attachments
I haven't bought anything Behringer in a while but still have a mixing console and a compressor. Back when I still cared about factory made equipment the common idea among musicians was "Behringer makes everything and everything they make sounds like p**p.".
Has that changed in some way? It's an honest question, not rethorical.
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Behringer has a great active speaker and lots of other well designed pieces of equipment. The UMC202HD is not the best measuring device, but price wise can't be beat.
It's been that for a while. soongsc and John Curl are part of the team as well, the brave Bybee defenders.
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Defending snake oil is one thing. Making and selling it with the deliberate lying is what I hate.
The HGA, a 12.1-foot reflector dish, transmits scientific and engineering data from the spacecraft to Earth using radio signals, which are picked up by NASA's Deep Space Network (DSN)—an array of giant, incredibly sensitive radio antennas. Voyager 1 is almost 13 billion miles away. Its signal takes more than 19 hours to reach Earth, and the power of that signal is less than 1 trillionth of a watt when it hits the DS
And they don't use Bybees or any other snake oil. Why do some people think it's necessary for audio.
And they don't use Bybees or any other snake oil. Why do some people think it's necessary for audio.
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