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Old 27th August 2013, 02:36 AM   #11
BHTX is offline BHTX  United States
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In my experience, one even becomes subconsciously accustomed to how the room influences the low frequency response at different positions (afterall, it is the main contributor in a small/average room with such low frequencies), and I think this can also have a large effect on being able to localize the sound. At the same time, it can also have the opposite effect. I often experience a subwoofer in a front corner of a small room while bass around a certain frequency (around 40 Hz in the last case I remember) is localized on the opposite side of the room, coming from the other front corner.
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Old 27th August 2013, 03:38 AM   #12
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Quote:
Originally Posted by markus76 View Post
^ Pressure gradients due to room modes can give misleading localization cues.

Other than that, do you have single sines, e.g. 35Hz? Close your eyes, turn around a couple of times until you don't know anymore which direction you're facing then play those 35Hz from one speaker with your eyes still closed. Are you still able to localize the speaker?

P.S. 0.5% THD at what SPL? My speakers have 0% THD when turned off
Hello

Yes, I can still able to localize the speaker.

Thank

Bye

Gaetan
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Old 27th August 2013, 06:48 AM   #13
BHTX is offline BHTX  United States
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Quote:
Originally Posted by markus76 View Post
^ Pressure gradients due to room modes can give misleading localization cues.
Ah. This sums up what I was trying to describe in the latter part of my post.
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Old 27th August 2013, 10:16 AM   #14
cristig is offline cristig  Romania
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Originally Posted by Pano View Post
But your subwoofer that you cross at 100Hz will certainly have harmonics, and you'll hear its position.
The distortion is mainly from the speaker itself, so it doesn't matter how low you set the crossover frequency.

For example I measured my YG Acoustics Carmel THD at 95db SPL at around -40db over 60Hz, but at 35Hz it is only -6db (amateur measurements with uncalibrated mic, so please get them only as an example to make a point, not as exact values). If you correct for the ear sensibility I am sure that at 35 Hz sine I hear mostly 70 Hz mixed with 105Hz.

With 60db Hz I can walk to my speaker with my eyes closed but if I don't move and try to point at the speaker location I make significant errors (even 30 degrees).

IMHO everyone can sense the difference between a mono subwoofer and stereo subwoofers , but if you have stereo subwoofers you won't be able to make a difference if they are separated from the speakers but not very far from them. But to get -20db THD at 30Hz from a speaker it's not easy, and -46db (0.5%) even at 20hz, not 10Hz, seems impossible to me at real SPL. For 100db at 10Hz with a 20 inch woofer you will need 1 inch of excursion, which if possible at all I doubt it will be linear.
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Old 27th August 2013, 11:31 AM   #15
AllenB is offline AllenB  Australia
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Gaetan, i tried this once and came across the same result as yourself. I went about sealing leaks, adding damping, reducing buzzes and changing amps, and IIRC I could still locate most of the bass.

A little harmonic distortion might not be such a problem in practice. Instruments will have harmonics anyway and it will be these that make bass instruments easier to localise.

In cases where much of the bass appears to come from the front centre then other issues might be making this a little pointless though.
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Old 27th August 2013, 10:11 PM   #16
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Hello

I did not done the thd measument of the woofer of my Dyaudio, but I've take it from this graphic from Dyaudio.

Bye

Gaetan
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File Type: jpg dynaudio17W75_02-thd.jpg (263.7 KB, 129 views)
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Old 28th August 2013, 06:30 AM   #17
cristig is offline cristig  Romania
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If I understood the graph correctly it was measured at 86db SPL and at 600Hz you get -36db distortion but at 35 Hz is -22 db (8%). At this level it means that for a 35Hz sine the distortion will be at 58db SPL and this can be heard as it is mainly a mix of 70Hz and 105Hz.
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Old 28th August 2013, 10:50 PM   #18
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Originally Posted by cristig View Post
If I understood the graph correctly it was measured at 86db SPL and at 600Hz you get -36db distortion but at 35 Hz is -22 db (8%). At this level it means that for a 35Hz sine the distortion will be at 58db SPL and this can be heard as it is mainly a mix of 70Hz and 105Hz.
Hello

No, in that the distortion graphic, the distortion level are raised by 20 db to fit all it in the same graphic (it's wrote in red on the graph. At 600 hz it's .2 % of distortion.

Bye

Gaetan
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Old 29th August 2013, 12:24 AM   #19
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~ -30dB from 60-80Hz
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Old 29th August 2013, 12:39 PM   #20
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Looks like -22dB at 35Hz as cristig said, distortion is ~2dB under speaker response on the graph.
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