What is the correlation b/w measurements and good sound?

[fas42]

These days relatively rarely change electrical parts, but years ago I did major surgery on power supplies - as a current example, I have a NAD 304 integrated which has good potential, but also a cheap and nasty volume pot - kills the quality quite badly. I've reorganised the attenuation circuitry to improve things, but still the pot is a dud - so, next step are some experiments with at least one new potentiometer of decent technical quality - see what that gives me. At the moment I run the setup with fixed volume ...

Expectation bias? If one is always going to use that as an excuse every time something is altered, and the sound changes then we're not going to get very far ... I changed to different, flashier looking speakers, and the sound changed!! No, no, it didn't, that was expectation bi.. ...

High SPLs? Sorry, I've been doing this for 30 years, I know what to look for ... back then I had a whopping big Perreaux amp, which started to cripple the treble at a very precise volume on a certain recording. Investigated, lousy power supply parts, replaced major chunks of this area - no more issues with this recording, and other such.

My methods are just as "subjective" as a garage mechanic being able to tell when a car engine is making the right noises or not ...

 

[fas42]

I don't know exactly what all is being said by fas42, but I know there are times when I can tell a system has "it" as in it's at the point where it really sounds like it should. That is opposed to something that's off for lots of reasons, despite having several pieces in it that are very good. I don't know how to measure this, and I won't pretend to have a working mind meter for it either. Sometimes you just listen to a stereo and you're like, "yeah, ya, it's there."

My experience is rooms can absolutely stop you from achieving that, but aren't as big of a problem as many people think. To me it seems like you tune to get the most out of the stereo and at some point you're squeezing because of an inadequacy in the electronics/power.

You're right on the money, Folsom. And, yes, I don't have an objective way to measure it either.

I've been surprised at how much can be squeezed out of the most unlikely setups, something I was exploring over the last couple of years. But at some point one needs to aim higher: low cost gear requires too much conditioning, too much time to stabilise, and the maximum SPLs will always be limited.

 

[Folsom]

Funny you say that, I personally believe a stereo starts with a power conditioner. But I frankly don't have a good suggestion because they're not cheap to make unless it's Best Buy quality. And a few of the less expensive ones have issues... I suppose if you could really make anything amazing for nothing without going DIY, this wouldn't be much of a hobby to care about since that would delineate the fact there isn't as far up to go, if true.

DIY is the only true option if you can't purchase good things. And that road still takes money and experience to get it all right.

But I disagree about SPL. I don't believe high SPL is required, but an amplifier and speakers that are linear enough while having proper solidity will entertain about the same at most volume levels. In fact turning it up hurts because it can't fool you into thinking it's not loud by having a softness to it on the edges of everything. A lot of stereos do their absolute best to counter this with power, but they've already lost the war since the same problem clipping incurs can happen at any volume with a lack of solidity (mostly from noise).

 

[opus112]

That is an interesting way of describing something. So you are observing the luminous ball of sound rather than being inside of it. This seems different from being washed over by the sound or being surrounded by it.

Yes, right - it definitely has a location in space, even though the edges are really, really fuzzy. I don't get (or so far, have not got) myself in the middle with sound washing all around me.

EDIT: I refer to something called Presence. Does the system create a believable facsimile of a live performance in the room and is there a distinction between the instruments making the sound and the sound filling the room? The really good systems that I have heard can do this. Other systems can not. Since this is in the measurement forum, and the thread is about the correlation between measurements and good sound, how is Presence measured?

I interpret your idea of 'Presence' as 'Thereness' - to me its about how much suspension of disbelief is called for when listening. I very much doubt that 'Presence' has a measurement but more than happy to be shown to be wrong...

 

[opus112]

How it can be "measured" is by directly analysing what is emerging from the speaker drivers, say the classic metre directly in front of one. I use my ears for this type of measuring, and what I listen for are artifacts that obviously are not part of the recording - eliminate those incorrect audible additions, and then the system has "presence", automatically - it's a process I've used over and over again, because it always works ...

I concur here - that's the nearest I would be able to come to a 'measurement' of how well a system is performing. If there's any sense at all of sound emanating from the surface of the tweeter (normally the problem area) rather than behind it, there's still work to be done optimizing. After all we are talking about accuracy here and nothing could possibly be that close to the microphone in the original, could it?

 

[fas42]

But I disagree about SPL. I don't believe high SPL is required, but an amplifier and speakers that are linear enough while having proper solidity will entertain about the same at most volume levels. In fact turning it up hurts because it can't fool you into thinking it's not loud by having a softness to it on the edges of everything. A lot of stereos do their absolute best to counter this with power, but they've already lost the war since the same problem clipping incurs can happen at any volume with a lack of solidity (mostly from noise).

No, it's not necessary for a lot of material, but certain recordings very much benefit. Classical, orchestral works are a prime example - the dynamics between soft passages and the climaxes need to be preserved, and if the system can't hold it together for that maximum volume then it never quite works. This reminds me of a casual listening session, years ago, when a classical music freak visited, and asked to listen to a certain recording - it was at a generous volume, and towards the end she was getting quite concerned, voiced her anxiety that it was too loud - meaning, she knew what the crescendo was like, and feared an audible catastrophe. But, it came, and rolled over us like a huge wave with no harm done to anything and anyone - this is true headroom, and makes for full enjoyment in the listening.

 

[BE718]

These days relatively rarely change electrical parts, but years ago I did major surgery on power supplies - as a current example, I have a NAD 304 integrated which has good potential, but also a cheap and nasty volume pot - kills the quality quite badly. I've reorganised the attenuation circuitry to improve things, but still the pot is a dud - so, next step are some experiments with at least one new potentiometer of decent technical quality - see what that gives me. At the moment I run the setup with fixed volume ...

Expectation bias? If one is always going to use that as an excuse every time something is altered, and the sound changes then we're not going to get very far ... I changed to different, flashier looking speakers, and the sound changed!! No, no, it didn't, that was expectation bi.. ...

High SPLs? Sorry, I've been doing this for 30 years, I know what to look for ... back then I had a whopping big Perreaux amp, which started to cripple the treble at a very precise volume on a certain recording. Investigated, lousy power supply parts, replaced major chunks of this area - no more issues with this recording, and other such.

My methods are just as "subjective" as a garage mechanic being able to tell when a car engine is making the right noises or not ...

Its not an excuse its a very real problem along with other biases. Why the subjective position cannot recognise this is very telling.

This is all just subjective tuning to your taste.

 

[BE718]

No, it's not necessary for a lot of material, but certain recordings very much benefit. Classical, orchestral works are a prime example - the dynamics between soft passages and the climaxes need to be preserved, and if the system can't hold it together for that maximum volume then it never quite works. This reminds me of a casual listening session, years ago, when a classical music freak visited, and asked to listen to a certain recording - it was at a generous volume, and towards the end she was getting quite concerned, voiced her anxiety that it was too loud - meaning, she knew what the crescendo was like, and feared an audible catastrophe. But, it came, and rolled over us like a huge wave with no harm done to anything and anyone - this is true headroom, and makes for full enjoyment in the listening.

Are you aware of how much more power you need to increase headroom? What is your definition of high SPL?

 

[opus112]

This is all just subjective tuning to your taste.

That's your subjective opinion but do you have any measurements or evidence in support of it?

 

[fas42]

Its not an excuse its a very real problem along with other biases. Why the subjective position cannot recognise this is very telling.

Okay, let's turn it around around then - how would you confirm that a meaningful change had taken place?

 

[fas42]

Are you aware of how much more power you need to increase headroom? What is your definition of high SPL?

Being able to hit in the region of 110dB at the listening position ... this compares to peak listening levels in a concert hall for the audience.

 

[BE718]

That's your subjective opinion but do you have any measurements or evidence in support of it?

Its not a subjective opinion, the evidence is Fas description of how he just listens and draws technical conclusions without measurement.

 

[BE718]

Okay, let's turn it around around then - how would you confirm that a meaningful change had taken place?

Now, the point in question was your statement I've found that a system when correctly working always has a "presence", irrespective of how correct or incorrect the room is. Both myself and others disagreed. I certainly think the speaker and room acoustics are extremely important - to the point where good systems can easily be ruined by bad rooms.

To this end I would use acoustic measurements to analyse the deficiencies in the room. Of course I listen, I but without those measurements its extremely difficult to fix the problems accurately.

 

[BE718]

Being able to hit in the region of 110dB at the listening position ... this compares to peak listening levels in a concert hall for the audience.

So how do you know your are reaching these levels without measurement?

So how do you know if distortion is caused by the amp or speaker if they are unknown to you?

 

[fas42]

To this end I would use acoustic measurements to analyse the deficiencies in the room. Of course I listen, I but without those measurements its extremely difficult to fix the problems accurately.

Of course the room would have deficiencies as regards being an ideal acoustic environment. But my perspective is that the room is a backdrop to a musical performance - consider having a real live proficient player of classical guitar in a "bad" room ... would you say to him, goodness, you sound awful here, cease playing until I can hear you in a "good space"?

As regards a number for high SPL, I'm not going to be pedantic about it - I'm familiar with the sensation of being a few rows away from a full size orchestra going for it, and standing just some feet away from a brass big band in full swing. There is a particular intensity happening at that moment, the sound fills your universe, if someone next to you says something at that moment they may as well be a fish gulping air - I'm not saying that's what I have at the moment, merely that achieving that would be the goal for a high SPL system.

IME the speaker is never the problem, it's always the amplifier - because every time I'm improved that amplifier the same, untouched speaker quite happily responds by producing better sound ...

 

[BE718]

Of course the room would have deficiencies as regards being an ideal acoustic environment. But my perspective is that the room is a backdrop to a musical performance - consider having a real live proficient player of classical guitar in a "bad" room ... would you say to him, goodness, you sound awful here, cease playing until I can hear you in a "good space"?

As regards a number for high SPL, I'm not going to be pedantic about it - I'm familiar with the sensation of being a few rows away from a full size orchestra going for it, and standing just some feet away from a brass big band in full swing. There is a particular intensity happening at that moment, the sound fills your universe, if someone next to you says something at that moment they may as well be a fish gulping air - I'm not saying that's what I have at the moment, merely that achieving that would be the goal for a high SPL system.

well I can enjoy a musical performance being played on my phone speakers while im relaxing in the tub in a tiled bathroom, but thats not the point is it? The point of hifi is to render an accurate rendition of the performance - it adds to the enjoyment of the performance. The room and its acoustics is a fundamental part of this.

Regarding power, assuming typical speaker sensitivity of 85 dB/w @ 1m you are probably going to need a good 300watts to get to your target and speakers that can cope.

 

[fas42]

Why do people always throw out the example of the tiled floor bathroom?!! ... It's just been my experience that any reasonable room will quite happily "support" competent playback - the simple reason being that the ear/brain can separate the threads of sound, direct and reflected, and still maintain the illusion of the sound image presented by the recording - the "art" captured by the producer is conveyed to the listener ...

The speakers I've used have been of the order of 90dB sensitivity or better, so I can just scrape getting near that region with typical amplifier powers. Amusingly, that old Perreaux had the numbers in the specs to easily kick the speakers loud enough, but was significantly flawed in raw form. And, always keep in mind I'm talking peak levels - I've had recordings of modern, highly compressed pop on - and it's impossible to play these anywhere near higher volumes; they overload one's emotional tolerance, my ears start ringing after just one song - but the speakers still take it ...

 

[BE718]

Why do people always throw out the example of the tiled floor bathroom?!! ... It's just been my experience that any reasonable room will quite happily "support" competent playback - the simple reason being that the ear/brain can separate the threads of sound, direct and reflected, and still maintain the illusion of the sound image presented by the recording - the "art" captured by the producer is conveyed to the listener ...

The speakers I've used have been of the order of 90dB sensitivity or better, so I can just scrape getting near that region with typical amplifier powers. Amusingly, that old Perreaux had the numbers in the specs to easily kick the speakers loud enough, but was significantly flawed in raw form. And, always keep in mind I'm talking peak levels - I've had recordings of modern, highly compressed pop on - and it's impossible to play these anywhere near higher volumes; they overload one's emotional tolerance, my ears start ringing after just one song - but the speakers still take it ...

I have never heard anyone throw out that example before, but it is an obvious example of an awful acoustic environment that would most definitely spoil the quality of replay from any hifi system. Ermm.... oh no it cant. So you reckon your brain can just filter out the effects of any acoustic environment???? Really????? So by definition, the science and very large industry of acoustics is a sham?!?!?

 

[fas42]

So you reckon your brain can just filter out the effects of any acoustic environment???? Really????? So by definition, the science and very large industry of acoustics is a sham?!?!?

Well, it does so most of the time ... when listening to real sounds, . And the key there is "real" - when the quality of the sound is high enough we can hear through amazing levels of muck, to pick up and identify the source. Including whether it's a live performance, or hifi playback! So, all we're asking is to reduce the difference between "real" and "fake" enough so the brain is fooled in that respect ...

The industry of acoustics helps the brain to get more of the message that is considered important at that moment - there's nothing wrong with using aids to make life easier for the senses.

 

[Fitzcaraldo215]

Well, it does so most of the time ... when listening to real sounds, . And the key there is "real" - when the quality of the sound is high enough we can hear through amazing levels of muck, to pick up and identify the source. Including whether it's a live performance, or hifi playback! So, all we're asking is to reduce the difference between "real" and "fake" enough so the brain is fooled in that respect ...

The industry of acoustics helps the brain to get more of the message that is considered important at that moment - there's nothing wrong with using aids to make life easier for the senses.

You are entitled to your opinion and/or beliefs, of course. But, I am getting a growing sense that you have just not yet experienced what effective correction of many prevalent room acoustics problems can do. Sorry, but 5,10,15 20 dB swings at relatively narrow frequency bands in the final response of your speakers in your room is not simply something most people can easily listen through, as you say, without compromising musical listening pleasure. Unless, that is, they have not heard the alternative that minimizes these wild swings.

I say these exist not just from theory, but also from actual measument in a fair number of rooms, which fully confirm elementary theory. I also say that hearing them corrected vs. uncorrected makes a world of difference, including not having to listen through the "muck". But, if you like, "muck", that is fine by me.

This issue is fundamentally distorting your sound. Yes, you can get accustomed to that and ignore it. Better yet, avoid making any measurements of your room/speaker response, so you will not actually and consciously know it is there. You can substitute beliefs for actual measurements freely. All the better to sing your system's praises to you and your ears. I am seriously doubting that most other listeners would agree if they actually heard it. But, your happiness with your sound and the paradigms that you espouse are up to you, even if they have no relevance to anyone else.