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rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
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Old 28th February 2018, 10:08 AM   #2451
arcgotic is offline arcgotic  Romania
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So IIR low pass & high pass, record with REW the response and then FIR to flatten the phase and SPL dips/spikes in the intended usable range? Is this what you are thinking?
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Old 28th February 2018, 10:24 AM   #2452
TNT is online now TNT  Sweden
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Quote:
Originally Posted by Rajapruk View Post
I never understod that ”an additional filter...” was an high-pass. I was stuck in thinking about the extra shelfing for the bass I want. Compensate + shelf, not compensate + high-pass + shelf. Do you see? You’re with stupid.
Why is this a "high-pass" filter? The function makes things flat. Then, if you don't want it flat you add an additional filter which can be anything you like - thats how I understand it?

The "high-pass" referenced above was just an example for an other user - there is no mandatory "high-pass" to be added as additional filter.

Right?

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Old 28th February 2018, 11:26 AM   #2453
BYRTT is online now BYRTT  Denmark
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rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
Think the "WHY" is because else you ask for non practicable real world boosts in compensate mode, below blue is 66Hz sealed box compensate and at DC potential it will ask for +70dB then the red one is a little more practical asking for 21dB boost rolling that sealed box system off at a BW2 20Hz.


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Old 28th February 2018, 11:38 AM   #2454
torgeirs is offline torgeirs  Norway
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Quote:
Originally Posted by arcgotic View Post
So IIR low pass & high pass, record with REW the response and then FIR to flatten the phase and SPL dips/spikes in the intended usable range? Is this what you are thinking?
Yes, if you ask me:-)
Nowadays in digital domain LP filter is optional:-)
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Old 28th February 2018, 12:04 PM   #2455
TNT is online now TNT  Sweden
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Originally Posted by BYRTT View Post
Think the "WHY" is because else you ask for non practicable real world boosts in compensate mode, below blue is 66Hz sealed box compensate and at DC potential it will ask for +70dB then the red one is a little more practical asking for 21dB boost rolling that sealed box system off at a BW2 20Hz.


rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool-3003-png
Fair enough. But is that "shelf" realized with a HP?

//

hmm, maybe it is - yes...
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Old 28th February 2018, 12:25 PM   #2456
BYRTT is online now BYRTT  Denmark
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rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
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Originally Posted by TNT View Post
Fair enough. But is that "shelf" realized with a HP?...
First we ask for the blue curve boost (compensate mode) up at 66Hz which is nothing other that a inverse normal 66Hz high pass function, then ad a normal 20Hz high pass and we get the red shelf.

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hmm, maybe it is - yes...
...
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Old 28th February 2018, 04:58 PM   #2457
BYRTT is online now BYRTT  Denmark
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rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
Quote:
Originally Posted by torgeirs View Post
A filter with minimum ringing in time response has Q of 0.5
The good old record player rumble filters had 12 or 24dB/oct.
A IIR in front of all FIR filters should be considered. But even such filter will have delay as groupdelay
Quote:
Originally Posted by arcgotic View Post
So IIR low pass & high pass, record with REW the response and then FIR to flatten the phase and SPL dips/spikes in the intended usable range? Is this what you are thinking?
Quote:
Originally Posted by torgeirs View Post
Yes, if you ask me:-)
Nowadays in digital domain LP filter is optional:-)
...think above points in all directions and is very hard to interpret and understand, is it encrypted : )
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Old 1st March 2018, 08:43 AM   #2458
torgeirs is offline torgeirs  Norway
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No encryption, just lazyness, he, he
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Old 1st March 2018, 09:00 AM   #2459
torgeirs is offline torgeirs  Norway
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I endorce your solution, Byrtt to straighten out the curve.
Actually just trying to point out that a 20Hz HP filter has been used for a long time to protect bass element from rumble. 12 to 24 dB/oct filter is common.
I forgot to mention the 0.5 Q applies to the IIR filter.
Use of IIR in low frequency is just to save latency. If the FIR filter is 200ms it is no need to bother with IIR in front.

The LP comment is just a comment about filtering RF pollution in analog domain. And certanly out of topic. Sorry
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Old 2nd March 2018, 06:25 AM   #2460
Rajapruk is offline Rajapruk  Sweden
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Another question about compensate.

If I have a filter enabled when I measure my drivers, for protection of the driver.
Is then ”compensate” the right way to ”remove” this filter, when designing crossover from this measurement?
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