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Help me solve this speaker distortion issue Studio Monitors
Old 13th October 2018
  #1
Gear Head
 

Help me solve this speaker distortion issue

I've been composing with some piano libraries lately, trying to achieve a very dark sound. I noticed that every time I would play the dark piano, no matter the library, I would hear some slight distortion, which I have never noticed before.
There is no distortion when listening to other music, both soft and loud, everything sounds like it always has to me. Also, with headphones I notice no distortion anywhere.
I hear the same slight distortion in a piece like this: YouTube
But not in a pice like this when the sub synth hits: YouTube
The latter I assume is because high frequencies are masking the distortion, whereas in Dream 3 or the pianos I play there is nothing on top.

So now my theories are two:
- my speakers are damaged
- my speakers used to be better then me, but now my ears graduated and started noticing their shortcomings

What do you think? Have you had this happening to you?
I have a pair of JBL LSR2328P coming out of my Apollo 8.
Old 13th October 2018
  #2
Lives for gear
 

I don't hear any distortion. Could it be the piano sound is exciting/buzzing something in the room?

Can you record the distorted sound so we can hear it?

WW
Old 13th October 2018
  #3
Gear Head
 

Quote:
Originally Posted by Bill Way View Post
I don't hear any distortion. Could it be the piano sound is exciting/buzzing something in the room?

Can you record the distorted sound so we can hear it?

WW
You are right, I forgot to include some very important details.

There is nothing buzzing in the room. The room is pretty much empty, and I'm 100% sure the distortion is coming from the area where the speakers are located, where there is nothing but the speakers and the stands. I can distinctly hear it coming from the left and the right speakers.

This is where it gets weird: the closer I get to the speakers, the less noticeable the distortion becomes. Could there be some psycho acoustic explanation to this?

I have uploaded some samples:
- one from monitoring position (roughly 1,5 meters from the speakers)
- one with the mic up close to the cone, about 2 inches away. This is level-matched to the first one
- the first file with a bandpass filtered centered around 2k, the range where I hear the distortion
- the second file with the bandpass filter. Notice how, though the non-filtered file was level-matched, the distortion is less noticeable here
Attached Files

mon pos filt.wav (1.96 MB, 118 views)

mon pos.wav (1.96 MB, 112 views)

up close filt.wav (1.96 MB, 122 views)

up close.wav (1.96 MB, 122 views)

Old 23rd October 2018
  #4
Gear Head
 

any clue anyone?
Old 12th November 2018
  #5
Gear Head
 

Last bump.
Just curious if this is normal for cheap speakers like this ($800ish a pair) and only now my ears are getting adjusted to it, or if this is an issue with my pair.
Old 12th November 2018
  #6
Gear Addict
 

Quote:
Originally Posted by saemola View Post
Last bump.
Just curious if this is normal for cheap speakers like this ($800ish a pair) and only now my ears are getting adjusted to it, or if this is an issue with my pair.
I'm almost sure that there's nothing wrong with your speakers in this regard.

I cannot download your files (plays back weird).
But even on my tablet I can hear some tension in the piano chords of the first youtube clip. The second clip plays less bass notes and simpeler chords.
The tension is the same that you'd normally hear when playing on an acoustic piano and playing chords in the lower register (more when throwing some dissonant notes in there).

This was the sound I used to hear when growing up paying acoustic piano, before there even existed electronic/virtual pianos, with exception of the Fender Rhodes.
Being accostumed to the clean electronic piano sounds nowadays, this tension does indeed sound like distortion.

In an untreated room, some frequencies, or frequency bands, can get boosted/exagerated in one location and attenuated in other spot.
So, it is completely possible that your acoustics is enhancing this part of the sound at your listening position, while damping it in other places,; moving closer to the speaker, you're probably moving out of the range of the typical first reflections, and maybe into a dip zone for that frequency band.

You can even test it like this:
Move to the position close to the speaker, where you do not hear this "distorton", then hold up a wooden board next to your head (sometimes even a piece of paper A4 works for this experiment).
The change in sound that you'll experience, is just a tiny showcase of the impact of acoustics on your sound.

I hope this sets your mind at ease.

Regards,
Old 12th November 2018
  #7
Gear Head
 

Quote:
Originally Posted by Prodba View Post
I'm almost sure that there's nothing wrong with your speakers in this regard.
[...]
I hope this sets your mind at ease.

Regards,
Hey Prodba, thanks for the reply.
I hear what you are saying, and I did entertain the idea of the room being the problem, but the thing is:
- the room is acoustically well treated. Primary reflections are well absorbed, ceiling included
- I think the distortion sounds way too high in the frequency spectrum to be a low frequency issue (I understand about low frequencies playing tricks in the upper harmonics, but we are talking the distortion being in the 2kHz here)
- this doesn't only happen in tension chords. It happens in a simple tonic + third chord as well if it's low enough.

It just sounds so much like distortion that I have a hard time justifying it some other way.
Do you think that a low frequency issue in my room (which I don't hear cause my room is fairly flat!) can create issues in the 2kHz range?
I guess my only solution is to somehow try other speakers in my room, but right now I don't know where to get them.
Thanks for the reply!

P.S. Maybe you said the files sound weird because they weren't clearly labeled. This is what they are:
mon pos filt.wav - recording from monitoring position, with a 2kHz bandpass to only let the distortion through
mon pos.wav - recording from monitoring position, full range
up close filt.wav - recording from up close to the speaker, with a 2kHz bandpass to only let the distortion through (distortion is less noticeable when up close)
up close.wav - recording from up close to the speaker, full range (distortion is less noticeable when up close)
Old 12th November 2018
  #8
Gear Addict
 

Quote:
Originally Posted by saemola View Post
Hey Prodba, thanks for the reply.
I hear what you are saying, and I did entertain the idea of the room being the problem, but the thing is:
- the room is acoustically well treated. Primary reflections are well absorbed, ceiling included
- I think the distortion sounds way too high in the frequency spectrum to be a low frequency issue (I understand about low frequencies playing tricks in the upper harmonics, but we are talking the distortion being in the 2kHz here)
- this doesn't only happen in tension chords. It happens in a simple tonic + third chord as well if it's low enough.

It just sounds so much like distortion that I have a hard time justifying it some other way.
Do you think that a low frequency issue in my room (which I don't hear cause my room is fairly flat!) can create issues in the 2kHz range?
I guess my only solution is to somehow try other speakers in my room, but right now I don't know where to get them.
Thanks for the reply!

P.S. Maybe you said the files sound weird because they weren't clearly labeled. This is what they are:
mon pos filt.wav - recording from monitoring position, with a 2kHz bandpass to only let the distortion through
mon pos.wav - recording from monitoring position, full range
up close filt.wav - recording from up close to the speaker, with a 2kHz bandpass to only let the distortion through (distortion is less noticeable when up close)
up close.wav - recording from up close to the speaker, full range (distortion is less noticeable when up close)


I do indeed hear this "sound" also in the non-tension chords here ( in the youtube clip), but maybe we're listening to different things.
Acoustics issues are not limited to the low end, and your console or desk can also be a cause of first reflections; issues around 2kHz are typically caused by boundaries very close by.

Maybe a stretch, but if you have a garden and long enough cables, you could setup a monitor outside to check whether you hear the issue in a more acoustics-free environment.

P.S.
The files playing weird, has more to do with my tablet, since I've had this happen before.
Old 12th November 2018
  #9
Lives for gear
 

Download the free REW.
REW - Room EQ Wizard Room Acoustics Software

Run a sine sweep test at different levels. Run it with a slow test (10Hz to 20,000Hz, length = 1M) and do one speaker at a time. And record it with your best transparent mic (omni SDC would be best but if not that, cardioid SDC pointed at the speaker being measured)

Increase the level and do it again.
If there's a driver problem, you should be able to hear it and/or see it in the recording.
Once you narrow it down (if there's a problem), you can pull up the Generator in REW and adjust the sine frequency until you find the exact problem (or problem driver)

That's pretty much how drivers are checked by speaker makers just they have standalone signal generators and measure the speaker driver in a closed box.
Old 26th November 2018
  #10
Gear Head
 

I sort of figured it out: it comes from the speaker, but not from the cone.
That might explain why I didn't hear with my ear right next to the cone, as the volume was too loud compared to the noise that up close.
It comes from inside the enclosure, from the bottom.
I thought it was some loose screw or something like that, but nothing rattles when shaking the enclosure.
I think my only option is to open it up and take a look inside, which is kinda scary.
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