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Subbass psychoacoustics: pitch perception?

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Category: General
Forum Name: Advanced Discussion
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=106238
Printed Date: 18 April 2024 at 10:02pm
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Topic: Subbass psychoacoustics: pitch perception?
Posted By: bob4
Subject: Subbass psychoacoustics: pitch perception?
Date Posted: 21 April 2021 at 10:28am
Hi,

I had recently a weird experience. A friend was testing a CKRAM (30hz tuned reflex, b&c 21DS115 loaded) outdoors.

Coverage and loudness was ok, but i felt the sound was a bit one notish, and i couldnt really make out the melody of the bass line in some songs. The source material was unfamiliar to me, so i put it down to bad production.

Incidentally, I shot a few bits of video with my phone to share and have as a memory. Listening back to those videos later, i noticed that I could clearly make out the melody of the bass line, that i had been unable to perceive when I was actually there!!!

Does anyone have similar experiences? Or a possible explanation for this phenomenon?

At home i have a dipole open baffle arrangement with two 12" woofers, that provides excellent tonal/pitch distinction, and strong output down to 30 hz. 



Replies:
Posted By: snowflake
Date Posted: 21 April 2021 at 11:01am
put the recording with your phone through an RTA - would be interesting where the HPF of the recording is, and what frequencies the bassline you can perceive is at.


Posted By: Sypa
Date Posted: 21 April 2021 at 4:41pm
Maybe distortion in the recording exposing the upper harmonics .


Posted By: bob4
Date Posted: 21 April 2021 at 6:27pm
My phone is a Samsung A50. It seems that it has a very low hpf, if any. In the "spectroid" app, I get readings down to 30 Hz. Although they appear consistently a bit rolled off (6 dB slope), no matter how I crank my setup at home or elsewhere. Thinking about it, I guess the rollof has to start around/below 40 Hz. 

I don't think it was distortion, I was standing about 40-50 meters away from the sub at that point. 


Posted By: bob4
Date Posted: 21 April 2021 at 7:06pm
This really puzzles me..... I play musical instruments, and have trained ears. 




Posted By: sarsen1
Date Posted: 22 April 2021 at 9:19am
Are you listening to the phone recording through headphones or out of the internal speaker? Could be little or no HPF on the actual recording but when played through the phones speaker, the speaker distorts and probably has HPF/limiter applied at that stage rather than the recording itself? 

Or perhaps the phones internal mic is voiced to pick up less low end (human voice ect) so the upper bass is more exposed on playback. Listening with ears and then listening through tiny phone mic and then ears is going to have a very different sound!


Posted By: bob4
Date Posted: 22 April 2021 at 11:54am
Originally posted by sarsen1 sarsen1 wrote:

Are you listening to the phone recording through headphones or out of the internal speaker? Could be little or no HPF on the actual recording but when played through the phones speaker, the speaker distorts and probably has HPF/limiter applied at that stage rather than the recording itself? 

Or perhaps the phones internal mic is voiced to pick up less low end (human voice ect) so the upper bass is more exposed on playback. Listening with ears and then listening through tiny phone mic and then ears is going to have a very different sound!

I listened back on standard Samsung earbuds, which admittedly don't have very strong low bass response, but with my beyerdynamic DT 770 pro I can tell there is definitely some content in the 40- 60 Hz range. I uploaded the video to youtube: 



As I said, I don't think this is an issue of distortion. What kind of psychoacoustic/auditory process could be going on here? There is the age old purported topic and phenomenon of "one note bass", which is sometimes attributed to bass reflex speakers.  

Clearly, I need to do some more field recordings with more appropriate gear at the next opportunity.

at the time that video was shot, I just dropped in rather late to catch up with my mates Embarrassed 

edit: listening back on my macbook speakers, there is not even a hint of the bass line, so again, I very much doubt that any recording and/or playback distortion is going on.....



Posted By: Elliot Thompson
Date Posted: 22 April 2021 at 2:53pm

Possibly the filter settings are too steep why you would hear a one note response from a Reflex Box. The Youtube video you have uploaded offers a response as follows...



The above response leads me to believe too steep of a dB filtration.


Best Regards,




-------------
Elliot Thompson


Posted By: toastyghost
Date Posted: 23 April 2021 at 10:54am
The CKRAM is hybrid sixth order box, not a reflex. Could you see the driver when it was being run? That might explain the difference in tone, since it’s meant to have a cover over it. Check the thread on data-bass forums.

But then also, as a hybrid bandpass box it will have a strong peak in the response by design.


Posted By: bob4
Date Posted: 23 April 2021 at 12:21pm
I have studied the discussion on data-bass...... without the attachment, it is basically just a reflex box with 30 hz tuned L- shaped shelf port......

Frankly, I was hoping for a general discussion on pitch perception in the bass range 30 -150 Hz, other peoples experiences of this kind or otherwise related......


Posted By: Elliot Thompson
Date Posted: 23 April 2021 at 2:09pm
You would have to play the cabinet without any means of a HPF,  LPF, in addition to, equalization to confirm the signal processing is not creating any severe phase issues. Phase issues can cause a sound to emit a peculiar sound from the original program material. Traditional Scoops, are notorious of creating their own sound caused by phase issues, due to the nature of it's design.

Since it is your first encounter hearing that design, you may want to give the box the benefit of the doubt. If you hear the box again used by someone else and, you encounter the same experience, then you can draw to the conclusion, that the box is the root of the phenomenon. 

Best Regards,





 


-------------
Elliot Thompson



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