How high is the distortion of your systems and what would you consider "clean" Output? - Distortion optimization and Listening Levels

[Oddball]

Do you have a measurement microphone? Can you tap an unbroken glass pane of similar size and record it from a close distance?

Maybe we'll be able to determine the resonant frequency.

I do have UMIC-1, but don't think it would be that useful. The resonance would be different and the only conceivable reason why this one broke would (although happy to take other suggestions) was that rubber seal was not holding it. With the new seal and glass, the resonance would be different.

As I noted before, the whole 2 window and door structure starts resonating at around 25hz > 100dB, so there is an obvious limit to what my room can take. No glass breaking, but the SPL of resonance becomes so loud that you obviously don't want to be hearing it.

 

[DVDdoug]

I don't worry about distortion unless I hear it and then it bothers me and I turn it down.

My home setup goes loud enough for (without audible distortion) plus I'm "careful" because I have nearby neighbors so I don't take full-advantage of it.

I have two vehicles - One with a factory stereo distorts badly on the bass when I turn it up.* The other one has a killer aftermarket system that goes loud enough, cleanly, to sometime make my ears ring! So I have to be "careful" for different reasons... It's very temping to crank it up with a good song when stays clean... Plus, it's a van with lots of wind noise and you can't hear the details on the freeway if you don't turn it up a bit.


* I haven't done any proper experiments but the bass SEEMS better with the sunroof open. An opening DOES act like a bass trap, reducing the reflected bass...

 

[Curvature]

Just a reminder as how powerful subs can be if you assemble a large fleet of them. And how not all structures are well equipped to deal with such power.

I found this review interesting in many ways, the one that I would call in this case was rebuilding the whole HT room/walls as they could not withstand the power of subs.

This is worth reading: https://www.baudline.com/erik/bass/thomas_danley.html

 

[RayDunzl]

Long ago I set out to measure compression and distortion.

Increasing sweep levels, not showing any noticeable compression. Room/Measurement noise intrudes on the lowest levels:

MartinLogan reQuest speakers

And list the Total Harmonic Distortion for each sweep.

The high distortion levels are at the lowest speaker volume.

It's not distortion, it's room/measurement noise.

Only at the highest speaker levels did the distortion products rise out of the noise floor, see the bunching at the lowest distortion levels - the highest speaker levels.

*the high disortion around 50Hz isn't, it's a room mode cancellation making the microphone see a lower volume around that level.


Moral of the story:

If measuring speaker distortion at home, and the speakers are of a low distortion type, get out your ear plugs because you'll need to sweep at 90dB SPL or more to get theditortion products out of the noise floor..


Suggestion:

Try some sweeps from low to high SPL and see where the "measured" distortion stops dropping and finally begins to rise.

 

[Oddball]

This is worth reading: https://www.baudline.com/erik/bass/thomas_danley.html

Looks interesting so will make sue to digest in time. Thanks for sharing.

 

[RayDunzl]

Test with JBL LSR 308
'
Compression - somethin starting to happen at the high SPL

And measured distortion much higher (and audible in the sweeps)

Once again, measured distortion drops. until the speaker distortion rises out of the noise floor.

The JBLs are my Daily Drivers, but they don't like to play loudly.

The MartinLogans are powered by baby Krells which wiggle far more electrons and have a heat penalty.

 

[Curvature]

Test with JBL LSR 308
'
Compression - somethin starting to happen at the high SPL

View attachment 464795

And measured distortion much higher (and audible in the sweeps)

View attachment 464797

Once again, measured distortion drops. until the speaker distortion rises out of the noise floor.

The JBLs are my Daily Drivers, but they don't like to play loudly.

The MartinLogans are powered by baby Krells which wiggle far more electrons and have a heat penalty.

Can you overlay all of the FR traces?

 

[Curvature]

Test with JBL LSR 308
'
Compression - somethin starting to happen at the high SPL

View attachment 464795

And measured distortion much higher (and audible in the sweeps)

View attachment 464797

Once again, measured distortion drops. until the speaker distortion rises out of the noise floor.

The JBLs are my Daily Drivers, but they don't like to play loudly.

The MartinLogans are powered by baby Krells which wiggle far more electrons and have a heat penalty.

Or, if possible, please share the mdat in a zip file.

 

[RayDunzl]

Or, if possible, please share the mdat in a zip file.

Dropbox

www.dropbox.com

Dropbox

www.dropbox.com

 

[Curvature]

Dropbox

www.dropbox.com

Dropbox

www.dropbox.com

For both comparisons I used the highest SPL and lowest without obvious noise. Aligned at 0dB and 1kHz.

Nothing I can see in the panel speakers.

LF limiting in the JBLs and a touch of compression beyond 15kHz.

 

[RayDunzl]

Can you overlay all of the FR traces?

You can do that with the .mdat files in the dropbox above.

 

[Curvature]

You can do that with the .mdat files in the dropbox above.

You'll see I've done so in the posts immediately above yours.

 

[RayDunzl]

Sorry, I was thinking something else.

 

[evanf]

-60db 1kHz and beyond. All other frequencies are less than 1%. Carver ALIII