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Combining drivers
Helge A Bentsen:
Attached is the phase plot of two drivers post equalization with the same reference delay.
What would be your method for combining these for the most linear phase response?
Russell Ault:
--- Quote from: Helge A Bentsen on March 02, 2021, 05:25:39 PM ---Attached is the phase plot of two drivers post equalization with the same reference delay.
What would be your method for combining these for the most linear phase response?
--- End quote ---
That red plot is barely visible on my screen. Is your coherence blanking jacked way up? Can you attach the two .trf to your post (or dump them out as ascii)?
Also, to make any meaningful recommendations it's important to see the mag trace as well, since the goal is phase alignment within the overlap band (and without the mag traces we don't know what the overlap band is).
-Russ
Helge A Bentsen:
--- Quote from: Russell Ault on March 02, 2021, 10:45:30 PM ---That red plot is barely visible on my screen. Is your coherence blanking jacked way up? Can you attach the two .trf to your post (or dump them out as ascii)?
Also, to make any meaningful recommendations it's important to see the mag trace as well, since the goal is phase alignment within the overlap band (and without the mag traces we don't know what the overlap band is).
-Russ
--- End quote ---
I've turned off coherence just to clear up the screenshot.
Also forgot to save the two captured traces showing overlap, this is with a Linear Phase BW crossover inserted.
Helge A Bentsen:
Btw, it's a measurement indoors in my awful sounding loading bay with the speaker on top of a road case.
Russell Ault:
--- Quote from: Helge A Bentsen on March 03, 2021, 04:40:32 AM ---I've turned off coherence just to clear up the screenshot.
Also forgot to save the two captured traces showing overlap, this is with a Linear Phase BW crossover inserted.
--- End quote ---
Ah, okay; the reason I thought you had coherence blanking jacked way up is because your crossovers are super steep and pass-band overlap is tiny.
It's been a little while; let's see if I still remember how to do this. (If I don't, I know someone will be along shortly to correct me; my apologies in advance.)
It looks like your crossover frequency is ~1.26 kHz. In the area of overlap between the two pass-bands (i.e. where there's less than a 10 dB level difference between the two mag traces) it looks like the LF is leading by ~15 degrees, and the HF is lagging by ~165 degrees.
To time-align the two passbands you'll need to add delay to the LF; specifically, you'll need to delay the LF enough to produce ~210 degrees of phase shift at the crossover frequency (15 degrees to go from leading to in time, plus 180 degrees to produce a wrap, plus another 15 degrees to go from 180 to 165), which works out to ~0.46 ms.
Does that sound about right?
-Russ
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