Speakers distortion

[Ron Texas]

This information surely looks relevant, so I find it safe to assume it's correct.

In that case it seems that in the whole recording/playback chain it is the speakers who remain dominantly responsible for the non-so-stelar SQ despite all the advance in the technology in last 20 years. Is that the conclusion?

I have seen it said many times that the single most important factor in SQ is the choice and placement of microphones. Having lower THD isn't the entire ball game.

 

[Krunok]

Distortion is at a higher frequency than the fundamental.

I have a 50Hz "node" (I guess).

The fundamental is partially cancelled (much lower in apparent level) at the listening position, the harmonic is not, so it calculates as a higher distortion level (ratio of harmonic SPL to fundamental) than is truly the case.

Maybe some future version of REW will take room characteristic into account when measuring distortion..

 

[Krunok]

I have seen it said many times that the single most important factor in SQ is the choice and placement of microphones. Having lower THD isn't the entire ball game.

You mean during recording?

 

[RayDunzl]

I wouldn't really use the term "smoked" as they seem very similar to me.

Btw, is that a different method of measuring distortion than the previous one you showed?

I was being appreciative to DJ, since (1) he provided an in-room measure (which is rare here) and (2) is the first I've seen to improve on my own lowish distortion measures, and (3) he smokes food to eat.

The first measure is a steady single tone.

The second uses a swept sine (20-20kHz) low to high over a second or two and it calculates the values for each frequency along the way.

 

[RayDunzl]

I can't play tones from my notebook via Volumio. Can I somehow make REW to generate a WAV file with that tone so I can put it on NAS and play it?
That is how I do when I measure frequency response.

Yes.

It's in the Generator window in the newer versions of REW.

 

[Ron Texas]

You mean during recording?

Yes, during recording.

 

[Krunok]

I was being appreciative to DJ, since (1) he provided an in-room measure (which is rare here) and (2) is the first I've seen to improve on my own lowish distortion measures, and (3) he smokes food to eat.

The first measure is a steady single tone.

The second uses a swept sine (20-20kHz) low to high over a second or two and it calculates the values for each frequency along the way.

So, can I use the same log sine WAV file as I'm using for frequency response measurement?

 

[RayDunzl]

I have seen it said many times that the single most important factor in SQ is the choice and placement of microphones. Having lower THD isn't the entire ball game.

Musical instruments themselves can register as 100% distortion (if the criteria is a sine wave, which is what distortion measuring software uses).

Additional distortion on playback is masked (not having a better word) by that.

Lower distortion playback (particularly of acoustic instruments) sounds "cleaner" to my ear, as there are not overtones added where they don't belong, changing the character of the sound.

Single note on a bass guitar (measured electronically, not in the air) as an example of why music isn't easily used to measure distortion.

By picking the string differently (closer to the end of the string), the second harmonic can be forced above the fundamental, and that yields 100% "distortion".

 

[Krunok]

I was being appreciative to DJ, since (1) he provided an in-room measure (which is rare here) and (2) is the first I've seen to improve on my own lowish distortion measures, and (3) he smokes food to eat.

The first measure is a steady single tone.

The second uses a swept sine (20-20kHz) low to high over a second or two and it calculates the values for each frequency along the way.

This is what I got. Your MLs of course smoked my Castles, but they didn't fare too bad.



How do you get REW to show distortion of both speakers on the same graph?

 

[RayDunzl]

So, can I use the same log sine WAV file as I'm using for frequency response measurement?

As far as I know, yes. Haven't tried it.

It's a specifically calculated sweep so REW should be able to do all its calculation upon the result.

 

[RayDunzl]

How do you get REW to show distortion of both speakers on the same graph?

Import (or just open) more than one measurement file (in this case, since the measures were his and mine at different times and locations).

Of if you already have two or more measurements, the Overlays window will show all (or selected) instances of the loaded measurements.

 

[Ron Texas]

All other things being equal, lower distortion is better. Unfortunately, all other things are not equal. Sometimes it boggles my mind to think that a bunch of separate sources of audio can be mixed down to two channels and produce a reasonable facsimile of the original performance.

 

[Krunok]

As far as I know, yes. Haven't tried it.

It's a specifically calculated sweep so REW should be able to do all its calculation upon the result.

Yes, it worked.

I can get 2 graphs in overlay window but not in the Distortion window although I have both measurements open.

 

[Krunok]

All other things being equal, lower distortion is better. Unfortunately, all other things are not equal. Sometimes it boggles my mind to think that a bunch of separate sources of audio can be mixed down to two channels and produce a reasonable facsimile of the original performance.

Other things being what exactly?

 

[RayDunzl]

Audible distortion can be reduced electronically.

A little experiment here.

 

[sergeauckland]

This information surely looks relevant, so I find it safe to assume it's correct.

In that case it seems that in the whole recording/playback chain it is the speakers who remain dominantly responsible for the non-so-stelar SQ despite all the advance in the technology in last 20 years. Is that the conclusion?

I certainly accept that all progress now needs to be in loudspeakers. ALL electronics is now transparent, unless the designer chooses it not to be, so that just leaves microphones, pickup cartridges and loudspeakers as the electro-mechanical items not yet 'perfect'.

Microphones we know (I think) aren't the problem, and pickup cartridges have other problems, mostly the vinyl, so that leaves the loudspeakers. Those are as yet nowhere near transparent, especially at the frequency extremes, so that's where the work needs to be. What's the point of a DAC or even an amplifier with distortion at -80 or even -100dB when few loudspeakers do better than -60dB, and that's at mid frequencies.

Sadly, in my opinion, many manufacturers still persist in chasing what people like rather than what's right, so we get so many flawed loudspeakers that people buy because 'they like them' not because they're any good. Manufacturers who make accurate DSP based loudspeakers are still in the minority, and as long as the magazines and forums persist in encouraging 'trust your ears' it won't change substantially. I really hope I'm wrong.

S

 

[Krunok]

Just to throw in a distortion measurement:

Same room, same signal path through the preamp stage.

I measured my little JBL LSR 308 at the SPL they start singing a different song

and the Martin Logan panels still sounding pure at the same room level...

Here is how it looks with my right speaker:



What do I have to set to make it looks like yours?

 

[RayDunzl]

'trust your ears'

I trusted my (faulty) ears 25 years ago, liked the electrostats, couldn't exactly say why then, still using them and haven't heard anything since that made me go "Wow". Being "happy", I haven't looked much.

My buddy said "Go shopping. Start with speakers you can't afford, to get an idea of what to shoot for."

 

[Ron Texas]

Other things being what exactly?

Frequency response, bass extension, dispersion, dynamic range and so forth...

 

[RayDunzl]

What do I have to set to make it looks like yours?

Interesting "broad base" there.

Try no averaging?

55dB is low - try 75 or whatever you're comfortable with.

---

Oh, I see, the broad base is a remnant of the beginning of the tone. Forever average and only 15 of them.

Reset the averaging - best way seems to be to turn the red button top right off and on again while the tone isn't stopped when averaging.