Dear experts,
I need your kind help and knowledge for understand if I’m on the right path or not. I’m doing a 3 way project MTMWW (SB 26ADC-C000-4, 2xTB w4-1337sd, 2xRCF L8S800). The idea is use an active XO (miniDSP 2x8) and 3 Crown XLS for run the drivers.
For the measurements, I have a UMIK-1 and an external sound card.
Here the simulation of the active XO based on the in box measurements (minimum phase)
After several nights of study, I’m still not sure I’m doing the right thing, and I would to know your opinions on the below
Question #1 – real time delay
I’m struggling to understand if there is a way to correctly measure the driver time delay: I’m using the methodology from “Finding the Relative Acoustic Offset in PCD” written by Jeff Bagby, but I would like to measure the result back to see if the drivers are really aligned after input in the MiniDSP the simulated delay. Can you please help me, or point to some tutorial? Is that possible?
Question #2 – phase alignment
I’m not sure I’ve understand yet the driver time alignment, and when they look good or not. In my simulation excel (Passive Crossover Designer 7 (2007)) I can get the phase – or at least I think so – but I’ve no idea if they are right. Below the results
All the measurement are “minimum phase” before the simulation
Can you please give me your comments or, again, point me to some “good phase” and “bad phase” alignment example, so maybe I can finally get it?
Question #3 – standing waves
I have done all the inbox measurement, and looks like nothing is wrong from the impulse and FR point of view, and I can’t hear anything strange when I run the sweep.
Is there any example or clear way to define if there are or not standing waves, and how to identify them?
Question #4 – protect the tweeter
Do I need to protect the tweeter? I will probably use a 2nd order filter at 4000kHz, is it still necessary? I can even use the amp capability to work as a low pass filter as safety net.
I would really avoid to add any passive components, because a 47uF capacitor in series it’s, at the end, a 1st order filter…
All the FRD, Impulse response, Phase, ZMA in box measurements available: I didn’t bother you with 16 pics yet
Thanks to all that will find the time to answer!
cheers
I need your kind help and knowledge for understand if I’m on the right path or not. I’m doing a 3 way project MTMWW (SB 26ADC-C000-4, 2xTB w4-1337sd, 2xRCF L8S800). The idea is use an active XO (miniDSP 2x8) and 3 Crown XLS for run the drivers.
For the measurements, I have a UMIK-1 and an external sound card.
Here the simulation of the active XO based on the in box measurements (minimum phase)

After several nights of study, I’m still not sure I’m doing the right thing, and I would to know your opinions on the below
Question #1 – real time delay
I’m struggling to understand if there is a way to correctly measure the driver time delay: I’m using the methodology from “Finding the Relative Acoustic Offset in PCD” written by Jeff Bagby, but I would like to measure the result back to see if the drivers are really aligned after input in the MiniDSP the simulated delay. Can you please help me, or point to some tutorial? Is that possible?
Question #2 – phase alignment
I’m not sure I’ve understand yet the driver time alignment, and when they look good or not. In my simulation excel (Passive Crossover Designer 7 (2007)) I can get the phase – or at least I think so – but I’ve no idea if they are right. Below the results


All the measurement are “minimum phase” before the simulation
Can you please give me your comments or, again, point me to some “good phase” and “bad phase” alignment example, so maybe I can finally get it?
Question #3 – standing waves
I have done all the inbox measurement, and looks like nothing is wrong from the impulse and FR point of view, and I can’t hear anything strange when I run the sweep.
Is there any example or clear way to define if there are or not standing waves, and how to identify them?
Question #4 – protect the tweeter
Do I need to protect the tweeter? I will probably use a 2nd order filter at 4000kHz, is it still necessary? I can even use the amp capability to work as a low pass filter as safety net.
I would really avoid to add any passive components, because a 47uF capacitor in series it’s, at the end, a 1st order filter…
All the FRD, Impulse response, Phase, ZMA in box measurements available: I didn’t bother you with 16 pics yet
Thanks to all that will find the time to answer!
cheers