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Multi-Way Conventional loudspeakers with crossovers

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 9th March 2019, 10:15 PM   #2661
chebum is offline chebum  Poland
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rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
Quote:
Originally Posted by pos View Post
What convolution engine are you using?
What do your EQs look like? (maybe show us a rephase graph screenshot, with any measurement bypassed)
At what SPL and dBFS level are you recording these measurements?
Thank you for the input, Thomas.

I'm using Equalizer APO. It uses FFTW3 for convolution. I doubt that's the case since the convolution causes no distortion if there are only high- or low-pass filters. The first chart included a 3-way crossover generated with rephase yet the distortion level was lower.

I'm attaching a screenshot with EQ settings for the tweeter.

Amplifier's volume setting was the same. Actual volume was lower due to the equalization applied. I'm attaching a volume comparison chart as well.
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File Type: png tweeter-settings.PNG (831.1 KB, 288 views)
File Type: png eq-no-eq.png (57.7 KB, 292 views)
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Old 9th March 2019, 10:32 PM   #2662
pos is offline pos  Europe
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Quote:
Originally Posted by chebum View Post
Amplifier's volume setting was the same. Actual volume was lower due to the equalization applied. I'm attaching a volume comparison chart as well.
You might just be seeing an increase in relative noise ratio then.
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Old 10th March 2019, 03:45 PM   #2663
JohnPM is offline JohnPM  United Kingdom
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It's a good idea to include the noise floor when looking at distortion plots, and to check the plot without normalisation.
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Old 10th March 2019, 06:59 PM   #2664
chebum is offline chebum  Poland
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rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
Quote:
Originally Posted by pos View Post
You might just be seeing an increase in relative noise ratio then.
Thank you for the suggestions. This indeed improved THD values.
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Old 11th March 2019, 04:27 PM   #2665
Rajapruk is offline Rajapruk  Sweden
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pos, when do you plan to release the bugs implemented last week on high altitude in the alps?
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Old 12th March 2019, 07:29 PM   #2666
thierry38 is offline thierry38  France
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A question (for fun/learning).


What about the :
Dolph–Chebyshev window (rePhase or REW) ?


Any trade-off ?


Click the image to open in full size.

Last edited by thierry38; 12th March 2019 at 07:34 PM.
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Old 12th March 2019, 08:18 PM   #2667
Juhazi is offline Juhazi  Finland
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About the distortion measurements of chebum, they were the farfield measurement of loudspeaker's output. We saw only distortion curves with percentage, not dB.

Typical domestic ambient noise level is 30-35dB. Typical hifi-loudspeaker must play at 95dB/1m or louder to show "real" distortion above noise level. One standard is to measure/set spl to 95dB at 1000Hz with some smoothing of response. Another way is to use standard voltage, but then we must also see the measured dB values to compare.

In theory, loudspeaker equalization always leads to higher distortion levels (when we look at spectrum). There is no way to raise efficiency or lower distortion by eq. When input voltage is lowered, distortion gets lower too. With eq we typically suppress loud parts of spectrum which leads to effectively lower total efficiency. Then, to get same spl level in a measurement (say that 95dB/1m), we must use higher voltage and we will see higher distortion percentage.

If quiet parts of response are amplified, distortion rises just as well and for same standard spl, we get higher distortion again. The problem with this is that we might introduce clipping in loud parts of music signal, in digital domain. It is very common to see music playing very close to clipping of even badly clipping because of "the loudness war" in original signal, so there is not room for eq left. The propability of this depends on where in signal chain spl volume control and eq is performed.
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Last edited by Juhazi; 12th March 2019 at 08:25 PM.
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Old 13th March 2019, 10:39 AM   #2668
pos is offline pos  Europe
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Quote:
Originally Posted by Rajapruk View Post
pos, when do you plan to release the bugs implemented last week on high altitude in the alps?
soon enough
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Old 13th March 2019, 10:41 AM   #2669
pos is offline pos  Europe
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Quote:
Originally Posted by thierry38 View Post
A question (for fun/learning).


What about the :
Dolph–Chebyshev window (rePhase or REW) ?


Any trade-off ?
I will look into that and implement it in the next release if it proves useful
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Old 17th March 2019, 01:53 PM   #2670
arcgotic is offline arcgotic  Romania
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Hello,
I noticed something when tested my DE250 on RCF H100 horn. Did a FIR and then an IIR high pass @ 1200Hz. The phase for the IIR filter is corrected with some 'compensate' 2nd order all-pass.

So the measurement looks the same but I can clearly say that the sound is more detailed/refined with the IIR filter. It has a better definition, 'bite'. I listen at low level, 70 to 85dB at listening position.

What is the cause? the pre-ringing of the FIR filter?

Thanks!
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