Measurements & Sound Quality

[fas42]

1 hour ago, kumakuma said:

 

I was thinking more of your posting history here on this site.

 

My apologies. I didn't appreciate that this was a site not interested in various methods used by people enthused about audio for improving their SQ.

[fas42]

Dear me. How to design an amplifier ...

 

Quote

The lesson of the Xs and SIT amplifiers was that a small amount of second harmonic of a particular phase character gives a desirable sonic result. To get that effect, we altered the arrangement of the constant-current sources in the output stage to better duplicate the sound of the Xs output stage. While the .8 amplifiers still have low distortion, they do not suppress second harmonic as much as the .5 series, giving a mostly second-harmonic character at ordinary listening levels and segueing into third harmonic at higher power.

, from https://www.stereophile.com/content/pass-laboratories-xa2008-monoblock-power-amplifier.

 

So, we've reached the point in 2018 where modern electronics by a highly regarded designer are "audibly transparent" ...

[Jud]

1 hour ago, Sal1950 said:

If my post made it sound like I was attributing that comment to Mr Pass, that was a mis-communication on my part. That sentence was strictly MHO. 

 

Yes - I thought it was a little ironic that it came at the end of a post praising someone who's said something different.   

[Jud]

59 minutes ago, jabbr said:

Great article!

 

Tremendously helpful and thorough.  Very kind of him to take the time to provide so much information to others.

[kumakuma]

38 minutes ago, fas42 said:

 

My apologies. I didn't appreciate that this was a site not interested in various methods used by people enthused about audio for improving their SQ.

 

"Put on a shitty CD, listen to what's wrong with your system, and then fix it" isn't a method for improving SQ.

[fas42]

4 minutes ago, kumakuma said:

 

"Put on a shitty CD, listen to what's wrong with your system, and then fix it" isn't a method for improving SQ.

 

It is, actually. The "poor" CD ruthlessly reveals the failings of the playback, because the combination of the recording content and the weaknesses in the chain make it extremely obvious - a "stress test". Then, changing various conditions while playing reveals the likely location - does changing the volume alter the misbehaviour? Does altering the level of electrical interference alter the situation? Does refreshing some connection in the rig change the SQ? Does varying how the components sit in position cause anything noticeable ... bit by bit you're learning where the chain is vulnerable.

 

With this knowledge in hand you're in a very good position to try some "fixes", and see what that gains.

[esldude]

3 hours ago, Jud said:

 

Alex, there was (may still be) an incredibly thorough website by a Pennsylvania professor who built a couple of these. The fellow also was active in the DIY Audio thread about this amp.  Yes, these are the big ones.  The price may or may not have been exclusive of case, but as I recall there were people who managed to get sources for those that weren't too bad either.

 

I'm at a holiday party at the moment, but will see if I can find links, perhaps tomorrow.

A true audiophile.  While at a holiday party, takes time to post and respond to other audiophiles.  

 

Man, it is Christmas, well almost.  That lousy sound stuff can wait until later.  

 

Besides how can they have a proper Christmas in Australia?  It is like the start of summer there.  Just ain't right. 

[Jud]

22 minutes ago, Jud said:

 

Tremendously helpful and thorough.  Very kind of him to take the time to provide so much information to others.

 

Regarding the cost, It was more than $400 even back then for 100wpc monoblocks.  My memory came from thinking about trying to do a stereo version, but it would have had to be lower powered for that price point.

 

Here's an excerpt of what Eric, the author of the article, said at the time: 

 

Quote

For me, this works out to about $700 per 100w mono chassis.... Overall, I suspect that I could build a lower powered stereo chassis for somewhere near $400 to $450.

 

Even so, getting yourself a pair of Pass-designed 100wpc monoblocks for $1400 then (I wonder what it would cost now?) would be quite something.

[Jud]

3 minutes ago, esldude said:

A true audiophile.  While at a holiday party, takes time to post and respond to other audiophiles.  

 

Man, it is Christmas, well almost.  That lousy sound stuff can wait until later. 

 

Most of the guests at the party were pretty interesting, but this one fellow was kind of a bore, and he was just about to show us the sixth picture of a bobcat family he'd taken with his phone (we actually get a fair number of bobcats around here, but his bobcats were bigger and better, which he was proving to us via his photos), so I took the opportunity to use my own phone for a minute.   

[kumakuma]

13 minutes ago, fas42 said:

 

It is, actually. The "poor" CD ruthlessly reveals the failings of the playback, because the combination of the recording content and the weaknesses in the chain make it extremely obvious - a "stress test". Then, changing various conditions while playing reveals the likely location - does changing the volume alter the misbehaviour? Does altering the level of electrical interference alter the situation? Does refreshing some connection in the rig change the SQ? Does varying how the components sit in position cause anything noticeable ... bit by bit you're learning where the chain is vulnerable.

 

With this knowledge in hand you're in a very good position to try some "fixes", and see what that gains.

 

I rest my case.

 

[esldude]

11 minutes ago, Jud said:

 

Most of the guests at the party were pretty interesting, but this one fellow was kind of a bore, and he was just about to show us the sixth picture of a bobcat family he'd taken with his phone (we actually get a fair number of bobcats around here, but his bobcats were bigger and better, which he was proving to us via his photos), so I took the opportunity to use my own phone for a minute.   

Man, I got some big bobcat pictures.  Should I share them??????  Somewhere or another on the PC I've got the recording of a rare puma screaming in the distance.  Well it sounds like a woman screaming, but its a puma.  

 

Or I could tell you about feeding a Micky D's hamburger to a bobcat once.  Don't have pictures though.  

 

Okay, so posting about audio was the right thing to do.  Still ain't right to have Christmas in the summertime.  

[STC]

On ‎12‎/‎22‎/‎2018 at 9:27 AM, fas42 said:

 

IOW, if we were to listen to live sound on the other of a wall, where there were only two openings to the other side, mimicing the positioning of stereo speakers, it would sound just like a hifi system! Of course, no-one has done this sort of experiment; because it might expose an Inconvenient Truth ...

 

I tired your experiment by listening to a conversation in a room through two opening separate by about 8 feet. Unfortunately, my hifi doesn't sound like it and I hope it will never ever sound like it. Even my lofi also didn't sound like it.

 

In fact, there are a few things you may want to reconsider before relying on this method. Let's take a stage of 15 feet wide. The small 1sq meter openings are 8 feet apart about 20 feet from the stage.

 

1) a drummer's at 5 feet from the center of stage to right will emerge about 2ms later from the left window.

 

2)  Another instrument just about 2 feet away from the center will emerge with a time difference of about 0.6ms.

 

The only way you could localize the instruments is by level and time difference. However, due to such a big distance the level difference will not be very useful as they will be too much of a difference than in normal hearing situation. If you are going to rely on time difference than anything above 600 or 700μs should arrive from the side. However, your pinna will locate them at the openings spots. The time difference will be totally wrong. The level difference will also be wrong.

 

At best what you are describing like someone with big head where the pinna distance is 8 feet. It is possible that after repeated training you could modify your hearing that would fit a giant's HRTF.

 

Posting this in a new thread so please reply there.

 

 

[fas42]

43 minutes ago, kumakuma said:

 

I rest my case.

 

 

Which tells me it gonna take a while still for audio to climb out of the hole it's in ... in the meantime, we will need things like Pass's amplifiers to 'mellow' the sound - like in the good ol' days, when they piled on perfumes to, ahem, obviate the need to take a bath on some sort of regular basis ...

[kumakuma]

8 hours ago, fas42 said:

 

Which tells me it gonna take a while still for audio to climb out of the hole it's in ... in the meantime, we will need things like Pass's amplifiers to 'mellow' the sound - like in the good ol' days, when they piled on perfumes to, ahem, obviate the need to take a bath on some sort of regular basis ...

 

I don't agree with the premise of your argument.

 

Things have never been better for audiophiles with great SQ even from entry level equipment and all the music we could ever need available at the click of a mouse.

 

 

[audiventory]

14 hours ago, STC said:

The only way you could localize the instruments is by level and time difference.

 

There sum (interference) of direct + bounced + re-bounced [infinite thin] acoustic rays from acoustic source in a point.

 

These rays may propagate differently for different frequencies (depend on source and its environment).

 

Sum  is complex (in math meaning) and it is sum of amplitudes and phases of all rays.

 

Rays have different sum in each point.

 

We can consider all surfaces of ears, inner ear, face bones as the points.

 

I suppose, there is many nerves are used in these points.

And brain get and process more sophisticated picture, then come to ears, to localize sound source.

 

 

To emulation of place of sound source, sound engineers can use:

• time delay between channels;
• level difference between channels;
• EQ;
• total source track level;
• other;
• complex of these action.

 

I suppose, modern systems try build ray propagation model and convert it according channel number.

 

Remarks:

• The rays are virtual. But they are need to classical math description of wave propagation and interference.
• Phase is like to time delay, but it is angle (angular coordinates).
• Sum is not constant. Sum is oscillation.

[sandyk]

14 hours ago, esldude said:

 

Man, it is Christmas, well almost.  That lousy sound stuff can wait until later.  

 

Besides how can they have a proper Christmas in Australia?  It is like the start of summer there.  Just ain't right. 

 

 I think that I would prefer the attached forecast. Nice and cool in the wee small hours for sleeping, and good for the beach or sitting indoors with air conditioning and some nice cold drinks with family and friends during Xmas day.

 

[fas42]

It's what you're used to - the weather, I mean. A couple of days after Christmas it's going to be over 40C, just down the road - take that!

[fas42]

5 hours ago, kumakuma said:

 

I don't agree with the premise of your argument.

 

Things have never been better for audiophiles with great SQ even from entry level equipment and all the music we could ever need available at the click of a mouse.

 

 

 

Access to music is excellent, yes. The low cost gear is extremely well sorted in raw form, yes. But the number of rigs that can produce convincing sound are just as sparse as ever - I don't bother going anywhere hifi shops , etc, because I would emerge with deep depression, from the sorry state of the 'SOTA' ...

[STC]

3 hours ago, audiventory said:

 

There sum (interference) of direct + bounced + re-bounced [infinite thin] acoustic rays from acoustic source in a point.

 

These rays may propagate differently for different frequencies (depend on source and its environment).

 

Sum  is complex (in math meaning) and it is sum of amplitudes and phases of all rays.

 

Rays have different sum in each point.

 

We can consider all surfaces of ears, inner ear, face bones as the points.

 

I suppose, there is many nerves are used in these points.

And brain get and process more sophisticated picture, then come to ears, to localize sound source.

 

 

To emulation of place of sound source, sound engineers can use:

• time delay between channels;
• level difference between channels;
• EQ;
• total source track level;
• other;
• complex of these action.

 

I suppose, modern systems try build ray propagation model and convert it according channel number.

 

Remarks:

• The rays are virtual. But they are need to classical math description of wave propagation and interference.
• Phase is like to time delay, but it is angle (angular coordinates).
• Sum is not constant. Sum is oscillation.

 

 

I am not sure how this is related with time and level difference.

[sdolezalek]

On 12/22/2018 at 6:37 AM, semente said:

 

In my view, the problem is that measurements are unrelated to taste and what most people do is evaluate sound/performance according to their taste instead of assessing it from an observationist perspective, just as a biologist would describe a particular specimen or event.

Ah yes, but isn't "taste" by definition a subjective standard?  Who says my taste is better than anyone else's? So a measurement that relates directly to taste can only confirm that there are a set of numbers that may be associated with that preference.  It's hard to think of a subject where people talk about "good taste", i.e. food, art, clothing, where numbers are used to prove the "good taste."

On the other hand, an observationist perspective might say the reason the bass sounds boomy to you is that there are, in fact, mid-bass, peaks in the response curve...So numbers can confirm observations and observations may align with what number would suggest you should hear.  

[jabbr]

19 hours ago, Jud said:

 

Even so, getting yourself a pair of Pass-designed 100wpc monoblocks for $1400 then (I wonder what it would cost now?) would be quite something.

 

Remember to pay yourself XX $/hr and consider the number of hours. So ... if you have fun spending time doing it, then great, but  the price ...

[Sal1950]

21 hours ago, esldude said:

Still ain't right to have Christmas in the summertime.  

Nope, there's nothing better than walking the streets at night, taking in the beautiful decorations, etc; on a lovely 75 or 80 degree evening. A total misconception you have to freeze your a-ss off to enjoy the holidays.

Just do be careful how you decorate your palm trees. 

 

[Jud]

2 hours ago, jabbr said:

 

Remember to pay yourself XX $/hr and consider the number of hours. So ... if you have fun spending time doing it, then great, but  the price ...

 

If I thought like that, I'd have no hobbies. If it's fun, that's not added advantage rather than a cost.  Not that a couple of NC400 kits aren't tempting.

[Allan F]

On 12/20/2018 at 7:43 PM, Jud said:

So even if you didn't know what to measure for musicians playing together, you know how to get your software to reproduce it.

 

Or not, if the other option is selected.

 

Query: Does the same result apply to all or most recordings? If so, the "other" setting arguably serves little or no purpose.

[Allan F]

On 12/20/2018 at 8:50 PM, STC said:

That's because you are listening to sound not music as a whole. A good sound engineer can hear the difference of 0.5dB but for rest of the music lovers it means nothing.

 

And what evidence, apart from your opinion, do you have to support this statement? More importantly, while it is true that a recording played at a higher volume is usually preferred, loudness is anything but the most important characteristic when it comes to sound quality.