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Multi-Way Conventional loudspeakers with crossovers

Freq measurements and Hypex Filter Design adjustments
Freq measurements and Hypex Filter Design adjustments
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Old 2nd October 2019, 02:00 AM   #211
PLB is offline PLB  United Kingdom
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Hi Steve,

Are you aware of the "Pink Cutoff(Hz) function in ARTA that has a selectable HP filter used for making measurements on tweeters?
When a measurement is made with this function set to say 1KHz, the inverse of this function is then applied to the data after aquisition. This provides you with a frequency response of the speaker without the response of the 1KHz filter!
So you don't need to apply a 1KHz crossover to the tweeter in order to protect it from excesive low frequency excursion.

Peter
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File Type: jpg Pink cutoff function.jpg (68.6 KB, 205 views)
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Old 2nd October 2019, 08:48 AM   #212
Steve2111 is offline Steve2111
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Default Freq measurements and Hypex Filter Design adjustments

Hi Peter,

No was not aware. But I see that it is not available under "Sweep"?
Not used Pink Noise for measurement before
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Old 6th October 2019, 07:16 PM   #213
Steve2111 is offline Steve2111
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Set up my living room for measurements again.
Just a few questions on ARTA set up.

I'm going to be measuring Tweeter, Farfield (1meter)
Going to risk HighPass LR4 at as low as 500Hz. (don''t know how to do with Pink Noise, Peter, as other drivers measured with Sweep)

ARTA Impulse response measurement/ Signal recording Window

Under Sweep generator:

Sequence length, 16K to 256K which and why?
Sample rate, I presume 48000?
Output Volume 0?
Log freq sweep - tick or not?

If later measure with Hypex FD (not done before) anything to consider?
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Old 7th October 2019, 02:41 PM   #214
AllenB is online now AllenB  Australia
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Sweep is good, it allows you to gate.

Regarding length.


0=0dB, normal full output.

Choose log sweep.
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Old 7th October 2019, 06:54 PM   #215
Steve2111 is offline Steve2111
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Default Freq measurements and Hypex Filter Design adjustments

Thanks Allen
Trying to understand the length link
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Old 31st October 2019, 05:57 PM   #216
Steve2111 is offline Steve2111
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Focal confirm TD5 XO at 2.5KHz (not 2KHz) You were right YSDR!
Also 15WX XO OK at 500Hz
ATC confirm they use range for SM 75-150S of 380Hz to 3.5KHz

If I use XO freq of 2.5KHz for the TD5, is the tweeter measurement in Post 201 with highpass at 1KHz good enough? The Highpass at 1KHz seems to affect the response from 2K downwards
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Old 3rd November 2019, 05:50 AM   #217
YSDR is offline YSDR  Hungary
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Yes, 1kHz highpass is usable for measurements for 2kHz and up, 2.5kHz and up is even better imo. My advice for xo point is still somewhere 2.5-3kHz.
Here is two 1kHz highpass response, one with BW2 (2nd order Q=0.71) and one with LR4 (two cascaded 2nd order BW2) for help.
As we an see even the LR4 is only around 0.5dB down at 2kHz. You can create these target responses in ARTA with ease, and it's useful.
1kHz_BW2+LR4_target.png
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Old 11th November 2019, 07:44 PM   #218
Steve2111 is offline Steve2111
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Default Freq measurements and Hypex Filter Design adjustments

Just some questions on ARTA
When try to truncate impulse measurement get:

Error:Gated length < 128samples

Need to go beyond 1st reflection in order to not get that message. See attached Trunc.jpg

Then with smoothing 1/1 get approx +/- 1dB see smooth1-1.jpg
with smoothing 1/24 get approx +/- 7dB of the same measurement See 1-24.jpg
Attached Images
File Type: jpg Trunc.JPG (87.5 KB, 82 views)
File Type: jpg smooth1-1.JPG (68.0 KB, 83 views)
File Type: jpg smooth1-24.JPG (71.3 KB, 83 views)
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Old 11th November 2019, 07:54 PM   #219
YSDR is offline YSDR  Hungary
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64k Sequence length is enough, but your impulse response looks strange to me. Please add little more gain in ARTA for better visualization.
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Old 12th November 2019, 08:42 AM   #220
Steve2111 is offline Steve2111
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Default Freq measurements and Hypex Filter Design adjustments

Impulse with 64K Sequence
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File Type: jpg 64k.JPG (485.5 KB, 49 views)
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