Hey guys, I'll need some help since this is my first build of a bookshelf speaker and crossover.
Basically, I've some weird phase shift around 3.7-4.8Khz (not sure if this is normal but I can also see some deep there in the FRD file) after measuring the speaker with the crossover which I built.
I am pasting below the REW measurement + the crossover design so hopefully some of you guys can help me out since as I said this is my first built and I am not much experienced to determine what may causing this issue.
I wonder, is it because the high impedance at around same frequency around 4khz as seen from the Xsim screenshot? And how I can avoid this?
Thank you in advance!!!
Basically, I've some weird phase shift around 3.7-4.8Khz (not sure if this is normal but I can also see some deep there in the FRD file) after measuring the speaker with the crossover which I built.
I am pasting below the REW measurement + the crossover design so hopefully some of you guys can help me out since as I said this is my first built and I am not much experienced to determine what may causing this issue.
I wonder, is it because the high impedance at around same frequency around 4khz as seen from the Xsim screenshot? And how I can avoid this?
Thank you in advance!!!
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It looks like the phase is close to -180 degrees, fluctuates a bit and the plotting routine fits everything into the interval from -180 to +180 degrees, causing wild jumps. For example, when the phase gradually goes from -179 to -181 degrees, that is mapped to -179 to -180 degrees, jump to +180 degrees, +180 to +179 degrees.
Thanks for your reply MarcelvdG!
So how I can avoid this or does this have something in common with the parts which I've used in the crossover? Also, can you simplify your answer coz it's a bit confusing.
Apart from that I've shorten the impulse in REW to avoid the reflections since I was measuring in my room but within that area there was noticeable drop which I guess is cancelation due to that phase shift...
So how I can avoid this or does this have something in common with the parts which I've used in the crossover? Also, can you simplify your answer coz it's a bit confusing.
Apart from that I've shorten the impulse in REW to avoid the reflections since I was measuring in my room but within that area there was noticeable drop which I guess is cancelation due to that phase shift...
What I mean is that the wild jumps are just a plotting artefact. The phase just smoothly goes down.
So as per you, is there something to fix there or no? Why there is a dip in that region SPL related?
It's more typical to look at unwrapped phase. There's a setting in REW for that, but it looks like you may not have used it.
https://www.roomeqwizard.com/help/help_en-GB/html/graph_splphase.html
That may not be the only issue though.
https://www.roomeqwizard.com/help/help_en-GB/html/graph_splphase.html
That may not be the only issue though.
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Good point, I did that but I am not much experienced so I wasn't sure what I was looking at... My goal with this crossover was to cross around 2500hz but it looks like this is crossing over around the same region where I see this shifts in phase so I guess that may be part of the problem which I am facing considering my Mid-Bass driver gaining impedance around that area.
Could be a mismatch in time alignment causing the phase to jump as it transitions from 1 driver to the other ?
Rob.
Rob.
I did nothing in that regard..., SpeakerBob, how I can fix that using my crossover? Is that possible? my Twitter is around 4cm forward of my acoustic 0 of the mid-bass.
The degree of phase shift is too big, no way 2000+ degree...
The first screenshot is starting from 3.7khz and the 2nd one is where it end up...
The first screenshot is starting from 3.7khz and the 2nd one is where it end up...
It is difficult to see where you've crossed. This may help in setting up the Xsim plot window..
https://www.diyaudio.com/community/threads/xsim-configuring-the-plot-window.406106/
Have you tried adjusting your measurement windowing?
https://www.diyaudio.com/community/threads/xsim-configuring-the-plot-window.406106/
Have you tried adjusting your measurement windowing?
AllenB here it's updated Xsim screenshot with the 2 drivers where they cross
Rob, the polarity of the Twitter is already reversed since I am using 2nd order LR Crossover, so by default this crossover shift the phase for 180 degree which require polarity switch. Are you recommending make it normal polarity just to see how the measurement will look?
Rob, the polarity of the Twitter is already reversed since I am using 2nd order LR Crossover, so by default this crossover shift the phase for 180 degree which require polarity switch. Are you recommending make it normal polarity just to see how the measurement will look?
So that's just how the driver behave there I guess we can't do much about it or?
btw have you looked at the problematic area and how you explain that phase shift...?
here is a screenshot of shortened impulse with wrapped phase to exclude the room...
And here is the same with unwrapped phase
