What objective measurements qualify as "High Fidelity"?

[terryforsythe]

Missed that twisted way you treated conclusions.

Twisted? Really?

If two people can read the same objective data and reach differing conclusions from the data, neither of which are provably incorrect, how would you explain it? In science and engineering such conclusions commonly are referred to as being "subjective". This forum is "Audio Science Review".

EDIT: To add further context, assume that there is a specification (e.g., an IEEE standard) that specifies criteria for a component to be considered "high fidelity". In that case, objective data measured for the component can be compared to that specification to determine whether the component satisfies the criteria. Thus, an objective conclusion can be reached - either it satisfies the criteria or it does not. Absent a specification specifying criteria that must be met, any conclusion, reached from reviewing the objective data, as to whether a component is or is not "high fidelity" is subjective.

 

[richard12511]

Good enough for me, but of course it falls apart again once you hit the transducer.

One could argue that the definition still holds true for loudspeakers, but it’s just unreachable with current tech. Still holds value as a goal though, even if it’s a goal that can’t be reached.

 

[kemmler3D]

One could argue that the definition still holds true for loudspeakers, but it’s just unreachable with current tech. Still holds value as a goal though, even if it’s a goal that can’t be reached.

The problem is that once you leave the realm of electronics you end up in the famous circle of confusion, or at least some confused shape.

If all (or even a significant number of) studios / producers agreed what kind of speakers were ideal for home listening and mixed to that standard, then we could compare our speakers to that standard objectively.

However, no such standard exists.

As such we can't say whether narrow or wide dispersion is more correct, whether more or less beaming in the treble is correct, or even exactly what target in-room curve is correct.

Hell, we can't even say whether dipole or omni are on the table or not compared to the "artist's intention", which I have always thought sounded good as a goal, but when you think about it, what do we actually know about that for the albums we listen to?

And this is before you even consider the parameters of the room. Is there a standardized RT60 curve, for example? No. How much early reflection is allowed according to the artist's intention? Is that even a worthwhile question to ask? Etc.

I think what you could say is that flat, phase aligned, on-axis anechoic response is most correct. But once you move beyond that, there is no more or less "correct" response, just opinions. Maybe good opinions, but no agreed-upon, known, objective standard.

 

[DanielT]

Whilst the above for electronics may be the SOTA , they are ludicrously excessive as a minimum standard for Hifi. THD of -60dB is perfectly adequate for transparency, and a S/N ratio of 80dB more than acceptable. Stereo separation of 20 -25dB is good enough for stereo, and a 20-20kHz response of 1dB sufficient, even 3dB wouldn't be audible at the frequency extremes.

It might be useful to do some blind listening tests to see just how tolerant we are.

S

For electronics, I usually have as a rule of thumb that it should be a factor 10 lower in distortion than the speakers, so around 65dB. That if I assume a "normal level" distortion in speakers of 0.5%. Really low distortion speakers, let's say 0.1% (which I don't have) so then around 0.01% /80dB distortion in the electronics. But that's just my own rule of thumb, which isn't really based on much other than that it somehow seems to make sense to have a bit of distortion headroom so to speak (I have no objective arguments for that rule of thumb).

Then we have the question of whether higher-order odd distortion is more unpleasant for the listening experience than lower-order even, but I'll leave that aside.

A bit OT:
I can unfortunately experience problems with pick up noise when I connect with too long and too RCA cables in my active crossover that has balanced inputs/outputs. But it's not the electronics' fault, just that I'm plugging in the wrong stuff in the sound chain.

Mechanically humming old transformers can sometimes be annoying, but it's the years that take their toll on electronics.

Other than that, I never experience any noise issues.

 

[Ron Texas]

So just to some up your position. The actual meaning of accuracy is meaningless in the context of high fidelity. Ok……..

It's meaningless as a naked definition without showing how it applies to hi fidelity. That's what I meant. It would have been enough for someone not intent on being a troublemaker. You haven't explained anything or added to the discussion. I'm done with you.

 

[terryforsythe]

On the subject of music recordings, the following passage from p. 11 of Floyd E. Toole's book Sound Reproduction (3rd ed., 2018) is pertinent:

Long ago, respected audio engineer John Eargle (1973) recognized the consequences of mismatches between monitoring and home systems in what is done during the recording process. Borja (1977) noted "dramatic and easily audible" differences in recorded sound quality caused by recording engineers compensating for spectral defects in control room monitor loudspeakers. He found that the inverse of the frequency response of the monitor loudspeakers could be seen in the spectra of the recordings. If the monitor loudspeaker had a response peak, the recording exhibited a spectrum dip - the engineer simply did what was necessary to make it sound right in the control room. This is not a new problem. Neither has the problem gone away. In an interview reported by Gardiner (2010) UK producer Alan Moulder, discussing the popular Yamaha NS-10M small monitor (see Section 12.5.1), said that "if you don't do anything they sound kinda boxy. They definitely make you work hard to make things sound right. You have to carve a lot out frequency-wise to make a track sound hi-fi." So, the process is to use a flawed loudspeaker and then equalize the mix to sound "hi-fi" to the mixer. Why? This mix can then only sound similar if reproduced through similarly flawed loudspeakers. This product and its distorted spectrum became so accepted by recording engineers that at at least one modern - fundamentally neutral - monitor loudspeaker has built in a switchable equalization to replicate it (http://barefootsound.com/technology) where they describe: "The 'Old School' setting captures the essence of the ubiquitous NS-10M, rolling off the sub-bass and top-end information, and bringing forward mid-range presence." So, the aberrant sound of the discontinued NS-10M may never go away.

 

[Ron Texas]

@terryforsythe that's a somewhat depressing analysis of the recording process. Things might have not changed since B&W 800 series speakers are used in many recording studios. Maybe that means we all need to have B&W speakers. I suspect not all recordings have this defect because many contemporary studio monitors tested here lack coloration. Maybe the problem is worse with older recordings. I also recall an article by a recording engineer who listened to his mixes on several different speakers and headphones. I have not doubt the problem is there. The question is how prevalent is it.

 

[Justdafactsmaam]

It's meaningless as a naked definition without showing how it applies to hi fidelity. That's what I meant. It would have been enough for someone not intent on being a troublemaker. You haven't explained anything or added to the discussion. I'm done with you.

In my first post responding to your goal I explained why your goal was unobtainium. Giving you a reality check about trying to use an inaccessible non objective reference, that being the intents of recording engineers is actually relevant to the discussion. Just because you didn’t want to hear that reality doesn’t make me a mean person or a trouble maker. It’s kind of how this forum works. If you are looking for a safe space to express ideas about audio that are objectively just plain wrong without being educated on the objective problems with your ideas this forum isn’t it. This forum is very much about reality checks.

 

[kemmler3D]

@terryforsythe that's a somewhat depressing analysis of the recording process. Things might have not changed since B&W 800 series speakers are used in many recording studios. Maybe that means we all need to have B&W speakers. I suspect not all recordings have this defect because many contemporary studio monitors tested here lack coloration. Maybe the problem is worse with older recordings. I also recall an article by a recording engineer who listened to his mixes on several different speakers and headphones. I have not doubt the problem is there. The question is how prevalent is it.

I tend to agree with this take. Yeah, you can easily find albums that were mixed in questionable ways, especially stuff from the 70s. On the other hand, even at the time, savvy people knew the NS10s weren't flat, and understood the value of a flat monitor. That was part of the BBC's goal for the LS series even back in the 50s. And (speaking from personal experience,) at least from the late 90s on, even teenagers mixing in their bedrooms knew that on-axis flat was necessary to get a good mix.

I don't know that the 70s was a complete dark age, and whatever it was, I think that phase has mostly passed. I would say that the circle of confusion has become smaller over the years.

At least now we assume (without too much uncertainty) that most studios are at least trying to mix with flat-ish monitors, and that many are using ruler-flat stuff like modern Neumann or Genelec stuff.

 

[Snarfie]

Frequency respons measured done with DSP like Mathaudio, Dirac, REW etc. It shows what is going on regarding your room modes probably for the first time.

 

[kemmler3D]

Frequency respons measured done with DSP like Mathaudio, Dirac, REW etc. It shows what is going on regarding your room modes probably for the first time.

It's been technically possible for 20+ years with software like ARTA, but not for free and not so easily. The real change has come with tools like EQAPO or the MiniDSP units, where it's now not very hard to do proper PEQ on a whole system.

I think this space is still moving fast. You can now do 10 bands of PEQ on a WiiM Mini which can be had for $60 if you find the right listing. Sonos has had automated room correction in their boxes for years. I think fancy stuff like Dirac ART could be (not to say it will be) available in $250 kits including a mic before too long.

 

[terryforsythe]

I suspect not all recordings have this defect because many contemporary studio monitors tested here lack coloration. Maybe the problem is worse with older recordings.

I agree on both counts.

I have both my family room and office systems tuned to a modified version of the Harman curve in which I lowered the bass boost. Some songs sound great, but more than a few sound overly bright. I suspect that songs that sound overly bright were mastered on systems that were lacking in the high frequencies. Sometime in the near future I am going to generate an additional tuning for each of my family room and my office where I tilt the high frequency response down a bit.

Almost every rock & roll recording before the mid-80s, and some later recordings, are lacking in bass. In my family room I have another tuning that follows the Harman curve, inclusive of the Harman curve's significant bass boost, and that sounds better for such recordings.

I have a miniDSP Flex HTx in the family room, which supports up to 4 tuning configurations. That makes jumping between different tunings as simple as pushing a button on the remote. In the office I use CamillaDSP. That will support a lot more different tuning configurations, and also makes it very simple to quickly change the tuning configuration with two clicks of a mouse or two touch screen selections.

As a side note, I always have been curious as to why older rock & roll recordings almost universally are lacking in bass. I went to quite a few concerts in the 80s, and the bass guitar and drums always were quite a bit more prominent live than they were on the albums. I wonder if when mastering older recordings engineers were concerned that too much bass being output by the speakers could cause a stylus to skip on vinyl records if people were not careful about their turntable placement.

 

[Ron Texas]

@terryforsythe the lack of bass in older recordings may be because the mix was optimized for vinyl which usually had poor low frequency capability. Large excursions would cause the stylus to jump out of the groove.

 

[Snarfie]

It's been technically possible for 20+ years with software like ARTA, but not for free and not so easily. The real change has come with tools like EQAPO or the MiniDSP units, where it's now not very hard to do proper PEQ on a whole system.

I think this space is still moving fast. You can now do 10 bands of PEQ on a WiiM Mini which can be had for $60 if you find the right listing. Sonos has had automated room correction in their boxes for years. I think fancy stuff like Dirac ART could be (not to say it will be) available in $250 kits including a mic before too long.

At least for me DSP is a game changer beeing 65 now.

Moved from a acoustic close to excellent house to a horrible acoustic new house living room/attic. Result did not listen for atleast 15 years to a close to 10.000 euro high end set. Did sold off most gear. Than around 2015 my i5 intel Lenovo laptop running Mathaudio Room EQ changed the horrible acoustic living room an attic ( mancave) into a almost Pro audio Controll Room could not believe my ears. I guess most important difference that such laptops an fast Intel i serie processors could not only measure your acoustics but also correct it without latency due to enough RAM memory an CPU speed so enough system recourses and OS is bit perfect an using for instance a WASAPI driver. Best investment i ever did in audio was buying 38,- measuring mic.

 

[gnarly]

He found that the inverse of the frequency response of the monitor loudspeakers could be seen in the spectra of the recordings. If the monitor loudspeaker had a response peak, the recording exhibited a spectrum dip - the engineer simply did what was necessary to make it sound right in the control room. This is not a new problem. Neither has the problem gone away.

Yep big time. It's not just peaks for monitoring/mastering, but the full tonal spectrum.

It makes the whole idea of "reproducing what the author(s) intended us to hear", whoever they might be, a total joke and a logical absurdity.

Hi-fi?, accurate?...simple... a flat transfer function of the system...which means a transfer function of signal to final speaker output. Stupid simple really.

Electronics? Yea, it can matter to final system transfer function..at least technically. Like technically, a pond (the system) rises when you pee in it.
Speakers, 100X more important...like the rain filling the pond.

Rooms, they are immaterial with regard to hi-fi/ transfer-flat system.....if your room sucks, get another room, but don't blame good equip.

 

[Miguelón]

In a thought experiment, to me “high fidelity” means that the signal source (mono) determines exactly a unique sound pressure function with a free parameter.

Such a function must reproduce linearly the signal voltage, so all proportions are preserved and the only free parameter will be the ratio between pressure and voltage.

All measurements should represent a deviation from the ideal function, as noise (random deviation), harmonic distortion (addition of multiples of a vector), FQ deviation (alteration of proportion), time delay (time displacement of the image from the domain)

 

[Justdafactsmaam]

In a thought experiment, to me “high fidelity” means that the signal source (mono) determines exactly a unique sound pressure function with a free parameter.

Such a function must reproduce linearly the signal voltage, so all proportions are preserved and the only free parameter will be the ratio between pressure and voltage.

All measurements should represent a deviation from the ideal function, as noise (random deviation), harmonic distortion (addition of multiples of a vector), FQ deviation (alteration of proportion), time delay (time displacement of the image from the domain)

Where? At the respective ear drum? At the speaker? A meter from the speaker? Anechoic or in room?

 

[Justdafactsmaam]

Yep big time. It's not just peaks for monitoring/mastering, but the full tonal spectrum.

It makes the whole idea of "reproducing what the author(s) intended us to hear", whoever they might be, a total joke and a logical absurdity.

Hi-fi?, accurate?...simple... a flat transfer function of the system...which means a transfer function of signal to final speaker output. Stupid simple really.

No such thing. You are taking a one dimensional electrical wave and converting it into a three dimensional acoustic wave form.

Rooms, they are immaterial with regard to hi-fi/ transfer-flat system.....if your room sucks, get another room, but don't blame good equip.

Rooms and speakers work as a system. Get another room? Usually easier to get another speaker

 

[Miguelón]

Where? At the respective ear drum? At the speaker? A meter from the speaker? Anechoic or in room?

Anechoic obviously, a meter from the speaker

 

[Miguelón]

No such thing. You are taking a one dimensional electrical wave and converting it into a three dimensional acoustic wave form.

Rooms and speakers work as a system. Get another room? Usually easier to get another speaker

In that case you can tune the function and adapt the room, once you have an enough accurate function (or constant transfer if you want). Without that you’re lost

If you don’t move from your listening position, you can neglect all extra dimensions when considering the resultant of all reflections. Is called on axis response and is 1-dimensional by definition of “axis”.