Why Some Audiophiles Fear Measurements

[Ethan Winer]

Are you [Reg] saying that there isn't the likely potential for a 30db variability created from room interaction? Are you saying that most loudspeakers aren't flat within 10db? I have a hard time accepting that someone who dismisses an argument with out addressing it's merit is someone who, "argues for a living".

I know the rule here is argue the facts and don't attack the person, which I agree with. But dammit, this typifies the problem with this person and others like him. It's clear he has nothing of substance to offer. He doesn't even try to defend his opinions with facts or logic. All he has are smarmy comments that express disagreement with no rationale. Thank you for pointing that out. I don't understand why he even posts in threads like this one.

--Ethan

 

[Gregadd]

BTW the way I have measured the in room frequency response form the listening position in my room using a spectrum analyzer on real music It is reasonably flat with the expected roll off in the bass you would expect for the ML/CLS.

 

[Ethan Winer]

I like this approach. The reasoning is clear. We could test it to see if people became satisfied with this way of looking at things. We could discuss a path to further refinement if necessary. That's how progress is made. It clearly argues why hi-fi listeners should spend a dominant amount of money, time and effort on the listening room. And it's provocative, since most listeners don't proportion their resources in this way. I really like it.

Once caveat, I would say his method would describe the % of sound we don't want to hear vs. the % of sound we hear. I would agree that 90% of unwanted distortion results from the acoustic environment.

Thanks guys. Of course, my little formula addresses only raw frequency response. It ignores distortion, such as a room's rattling windows as Amir mentioned. And it ignores ringing which occurs in rooms but not competent gear. But still, as a crude metric it seems to make the point well. If the goal of "high fidelity" is to minimize unwanted coloration, then clearly the room does more coloring than anything else by a huge margin.

--Ethan

 

[Bruce B]

Every room needs some kind of room treatment but through many years hearing other than my system I never found a system where the room ( with out treatment ) was so bad that the system were unlistenable.raul.

Guess you were not at the last PNWAS meeting!!

As with Mike, I too find Ethan's figures skewed. Remember, he has the most to gain.

 

[Ethan Winer]

Wouldn't that be mostly below 300hz or so or where the room has the dominant effect on what we hear??

Different frequency ranges show up as different types of room problems, but they all color the sound in an undesirable way. You still peaks and deep nulls above 300 Hz, and you also have reflections arriving after the direct sound which "smears" (I hate that word) the music.

--Ethan

 

[Ethan Winer]

IMD in speakers is an audible distortion where IMHO room treatment can't disappear because that IMD " born "/ is part of the speaker behavior.

Sure, but it's still a useful metric to make the point that rooms color the sound infinitely more than anything else in the signal path. Your argument that higher order harmonics are "aggressive" pales in comparison to the typical 30 dB peak/null spans you get in untreated rooms. IMO, any gear whose distortion is plainly audible, let alone aggressive, is defective.

--Ethan

 

[Ethan Winer]

he has the most to gain.

I resent your implication that I explain audio science for financial gain. If that's the best you have to offer, please find another thread to post in. Thank you.

--Ethan

 

[Ethan Winer]

Ethan,
that was my point about cabinet resonance, driver issues,etc.
You mention Frequency response, Distortion, Noise, Time-based errors.
However I have now pointed out a fundamental requirement relating to time domain, this means your Frequency response is just data collected that has no meaning unless integral to a specific test, in this instance such as a more complex test that provides waterfall plot measurement-data, on top of this speaker sound is also compounded by impedance/phase of the speaker and the output impedence (a critical factor)-power supply stage and output stage-design of the power amp.
Again this affects Frequency response.
The problem IMO is that you can say frequency response covers the majority of measurements, but it has absolutely no meaning outside of its test scope, because a lot of what I mention above are frequency related but tested in different ways and have different implications.
It may seem I am being picky but this is critical as I see often many assume that its the simple single frequency response that tells us everything for speakers-preamps-DACs (they do sound different when you consider the various reconstruction filters) and possibly quantisation/aliasing that can throw ultrasonics into the respecting pre-power amp.

Relating to driver breakup, again IMO the problem is that a waterfall plot will show implications of cabinet and driver than distortion measurement.
Why?
Look at a speaker's measurements at 90db at 1 metre for distortion, and then look at the waterfall plot, the only one that tells you there is a potential problem is the waterfall plot.
And again distortion does not tell us what is occurring in the time domain, where we can see that it acutally fluctuates in the time domain and not all are equal in behaviour.

The big question though Ethan, is how do you prove your hypothesis if you do not find several reviews that reach the same conclusion or perception of a speakers sound and then compare it to the detailed speaker's measurement?
Even HK have to correlate measurements to a listener's perception in their testing.
You could be right, but it really is important to try and match that hypothesis (because it is not proven just yet) to measurements and how it matches a listeners perception.

Relating to the Nad and ARC Ref 5, I am tempted to be very cheeky
Heck yeah why not hahaha, if we go with your point about 60k load and even say sensitivity-impedance matching-etc, then this suggests all source-preamps-poweramps will sound different even when measuring well and this has nothing to do with frequency range/distortion/errors and yet you argue all preamps and power amps that have flat FR-noise are sonically transparent
More seriously, the measurements done by Paul stopped at 4th harmonics because the dominant ones (2nd) were before that and beyond 4th they were insignificant (even 3rd and 4th were very low)
Also I agree to a certain point about the 60k load, but then frequency response related measurements are not exactly accurate as it takes a single sinewave usually at 1khz.
Also I am yet to see any test procedure that uses sine sweeps anywhere comparable to say a musical chord from one instrument that is vastly more complex.

That said, the 60k load as I mentioned before is a long stretch for why a zero feedback tube design and a cheap implemented feedback design different using Jeff's descriptions.
Especially when the distortion and FR measurements are negligle in terms of difference, unless you think changing the load will dramatically alter this over 20-20khz?
If so would be interested to know how, and thats the important part of the debate.
If 60k load is an issue, how will it affect the negligible measurements relating to distortion-FR-Noise that you mention, bearing in mind as we see in the two preamps they have significantly stable measurements?
This does not square with your statement:

The measurements ARE comparable in terms of audibility, unless your now using the subjectivist argument and saying we are not measuring everything between the Nad and ARC to show differences
And then this would be skewing the argument possibly towards a bias/favour because ALL measurments done historically by Soundstage/SP/Hifi news/etc take a specific load/sinewave/etc and are better than anything I have seen users or manufacturers do.
This is important because your arguing the measurements I provided may not have meaning while also saying well designed amps-preamps are sonically transparent, when I doubt no-one will state a cheap solid state feedback designed preamp sounds the same as a tube preamp with zero feedback as shown in my example that IMO are comparable enough with their measurements to be used for this debate.

I could expand the debate to flat 20-20khz DACs but they can subtly sound different due to different filter implementations, or the engineering debate relating to negative feedback where two opposing well regarded engineers can show how negative feedback does have a behaviour on the amp and one goes states position for none (Nelson), while the supporter argues that it should be heavily implemented (however Bruno also goes on to say well implemented negative feedback is not cheap).

I could go on, for me its an interesting debate and hope you continue discussing this Ethan along with maybe Jeff/Myles/Amir/Don/etc piping in as it would make sense for them to correct me where I made some mistakes or add their views to the specifics we are talking about.

But, at some point we do need to correlate the good listeners' perceptions-reviews to those of their real measurements and show how they fit in with either hypothesis (I agree even the data-measurements I am showing do not go that far to answer those outlined by Jeff).

Thanks
Orb

The majority of that flew over my head, and I'm not sure all the point(s) you're trying to make. So I'll address just the parts I understood:

you can say frequency response covers the majority of measurements, but it has absolutely no meaning outside of its test scope

Frequency response determines overall tonal color, which is probably the most important thing everyone notices whether they're a professional listener like Bruce Brown or a six year old child. Yes, frequency response is not everything, but it's a lot.

As for the preamp specs, they didn't even list IMD. So the common belief that "two devices measure the same yet sound different" is not proved by that set of specs anyway.

--Ethan

 

[Ethan Winer]

If you transfer that 99% figure into dollars that means for every 100 dollars, 1 dollar would be spent on the front end. 10 dollars for a 1000 and and a 100 dollars for 10000 dollars.

Now there's a logical flaw if I ever saw one. Who said that one's allocation of funds should follow the same proportions as importance to sound quality?

--Ethan

 

[Ethan Winer]

as a person who has expended as many resources as anyone on room design and acoustics, i find that absurd (the idea, not the person).

What I find absurd is saying only "You're wrong," without bothering to type even one sentence explaining why I'm wrong or what is right.

--Ethan

 

[Ethan Winer]

I have measured the in room frequency response form the listening position in my room using a spectrum analyzer on real music It is reasonably flat with the expected roll off in the bass you would expect for the ML/CLS.

Now that's a graph I'd love to see!

--Ethan

 

[Ron Party]

Raul, I enjoy reading your posts inasmuch as I think we both seek some or possibly even most of the same qualities out of an audio reproduction system.

I wanted to ask you a few questions about your view of what role the room plays in the reproduction of music. Specifically, I refer to the following post of yours:

Some people think that the best about room treatment is to try the room " disappear " and I don't think in that way.

For me the room must put his " color " in the whole audio " picture " just like a phono cartridge or speaker does because the music, at least the music I heard/hear live, does not comes in a " free space " but within/inside a room: music hall, jazz club and in home. The " color " that the room impart at the music/sound reproduction in a home system is really important and I'm not to sure if we have to look for absolute neutrality when even on musical instruments there is no " neutral " sounds, each instrument has its own " color ".

I always try to look for that music natural " color " trying to avoid errors/exaggerate " colorations ".

At first glance, it seems as if you are straddling the fence on this one. "I'm not sure if we have to look for absolute neutrality" and "trying to avoid errors/exaggerate colorations" seem inconsistent.

This ties in to another part of your post: "the music I heard/hear live, does not comes in a 'free space' but within/inside a room: music hall, jazz club and in home". My question to you is: do you want to hear the music as it sounded in the venue where the musicians were playing, or do you want to hear the music as if the musicians were playing in YOUR room? If the first, it is arguable the pursuit of a neutral room is the goal. If the second, then all bets are off.

 

[microstrip]

There are four parameters that affect audio reproduction:

Frequency response
Distortion
Noise
Time-based errors​

Do you also have a similar set of parameters to measure rooms? Something we will look at and say immediately "My room sounds excellent!" without listening?

 

[Ethan Winer]

Do you also have a similar set of parameters to measure rooms? Something we will look at and say immediately "My room sounds excellent!" without listening?

Yes, of course. The metrics for room measuring are frequency response (which of course must include the loudspeakers), and decay times versus frequency. There's another metric for the strength of individual reflections, though reflections are the cause of a skewed response. My final upcoming article in the Room Measuring series at my own forum section will show several graph types and explain how to interpret them.

--Ethan

 

[Orb]

The majority of that flew over my head, and I'm not sure all the point(s) you're trying to make. So I'll address just the parts I understood:



Frequency response determines overall tonal color, which is probably the most important thing everyone notices whether they're a professional listener like Bruce Brown or a six year old child. Yes, frequency response is not everything, but it's a lot.

As for the preamp specs, they didn't even list IMD. So the common belief that "two devices measure the same yet sound different" is not proved by that set of specs anyway.

--Ethan

Ah sorry I think what makes it harder reading my post is I dislike quoting someone's lengthy post and break it down with each debate point back.
Basically if you look at your last post to me, this is a response to yours but I appreciate I have made it trickier by not quoting yours and breaking it down in line with mine.
Apologies but if you read your response to me earlier and then mine it make more sense, I am laughing now because I can appreciate your going to have to open another browser to read your post probably along with mine, sorry
BTW I agree with tonal aspect, and this was also mentioned in the link I provided titled :Frequency Response Isn’t the Only Thing.
http://www.ultraaudio.com/opinion/20100501.htm

Cheers
Orb

Edit:
Can you expand on the IMD and show me anyone who has done that test-measurement as a full measurement test where it is not low.
Because even though distortion is measured; distortion vs frequency/distortion spectrum at 1khz/distortion spectrum at 20khz/distortion vs output level/distortion vs input, the reason these two products sound different is down to not knowing IMD?
Do you feel from your own experience though that a cheap negative feedback preamp and a reference spec tube zero feedback preamp are both transparent (in other words audibly the same) and when not it must be IMD or some other factor not measured by PM?

Orb

 

[kareface]

Every room needs some kind of room treatment but through many years hearing other than my system I never found a system where the room ( with out treatment ) was so bad that the system were unlistenable

You see them all the time, you just don't realize it. Small room sound mechanics allow for a a lot to be wrong with out you picking up on it. As you scale the size of the room up the problems become more audible because the delay increases. Linear forms of FR distortion are harder to pick up on, but when you remove them from the room the changes are immediately noticeable, even with just the ambient noise. The distortion isn't as visceral as other forms, so you don't recoil at untreated rooms like you would with a poorly designed amp, but the problems are no less audible.

I would add, Bruce, I think your comment was unwarranted. I work with room treatments myself, but I'm not accepting new clients before the start of the next academic term, I currently have nothing to gain from the promotion of room treatments yet I would gladly explain their benefits to anyone that was willing to listen. You can look at it 2 ways, he could be shamelessly promoting his own products, or he could have first hand experience of the results from proper acoustical treatment and be willing to convey his experience on the subject. Given his willingness to dispel other misinformation unrelated to room acoustics, which wouldn't benefit him at all, I would wager it's the latter of the 2 options. I personally don't think Eithan is ill-natured. Even if he was (which he is not), his motivations are unrelated to the validity of the premise.

 

[silviajulieta]

Raul, I enjoy reading your posts inasmuch as I think we both seek some or possibly even most of the same qualities out of an audio reproduction system.

I wanted to ask you a few questions about your view of what role the room plays in the reproduction of music. Specifically, I refer to the following post of yours:


At first glance, it seems as if you are straddling the fence on this one. "I'm not sure if we have to look for absolute neutrality" and "trying to avoid errors/exaggerate colorations" seem inconsistent.

This ties in to another part of your post: "the music I heard/hear live, does not comes in a 'free space' but within/inside a room: music hall, jazz club and in home". My question to you is: do you want to hear the music as it sounded in the venue where the musicians were playing, or do you want to hear the music as if the musicians were playing in YOUR room? If the first, it is arguable the pursuit of a neutral room is the goal. If the second, then all bets are off.

Dear Ron Party: When I was typing the post I question me the same but then I thought that looking for a neutral room is an almost impossible target to achieve, so I have to accept some kind of trade-off here. I think that it is important here to add what I posted: "" always try to look for that music natural " color " """": natural color, this is the key for neutrality.

The other question: neither, I'm looking to hear what is in the recording. Yes, to achieve this target we have to look for a neutral room. My " doubt/dude " about " room neutrality " is : how can I know an audio home system room is absolute neutral? exist in real life that kind of room that add nothing and than lose nothing? , I can't say it for sure and always could be the subject that even if exist a neutral room that romm could be neutral only with that system: if we change speakers or amplifiers or the like then probably we have to make some additional room changes to preserve that neutrality.

It is not ( at least for me ) an easy answer because imply many other things and some of them are out of my know-how and experiences. As an answer to my target: yes I need a neutral room to hear what's in the recording.
To hear or heard what's in the recording we need neutrality an accuracy in each single audio link where the audio signal must pass and the room is one of those links, so neutrality is a must to looking for. Coul I achieve it?, certainly not but that's the target and the quest to looking for lower and lower and lower colors in the audio links and certainly to be there we need our ears and measurements too.

Regards and enjoy the music,
Raul.

 

[Randall Smith]

BTW the way I have measured the in room frequency response form the listening position in my room using a spectrum analyzer on real music It is reasonably flat with the expected roll off in the bass you would expect for the ML/CLS.

Is this a serious post? You measured real music in your room? Does your music measure flat? Maybe you should put your moderator hat on before you lose all of your credibility.

 

[microstrip]

Yes, of course. The metrics for room measuring are frequency response (which of course must include the loudspeakers), and decay times versus frequency. There's another metric for the strength of individual reflections, though reflections are the cause of a skewed response. My final upcoming article in the Room Measuring series at my own forum section will show several graph types and explain how to interpret them.

--Ethan

Thanks - I will keep my questions until that moment. But, meanwhile, I can not stop from asking if it is so simple why all the others kept us waiting so long, telling us that we need experts to analyse rooms ...

 

[Ron Party]

Thanks, Raul. I think I understand what you are saying. As I said before, I think we share the same philosophy.