We would be a lot more help to you if you showed the filtered measurements like I suggested in post # 712.
Without that information, we are left to guess at what you are doing.
Here's a sim inspired suggestion. Might not work, but sure looked good in the sim. It's simple. Change the mid filter to 4th order Butterworth at 2.1K. Leave the tweeter at 2.5k LR4. Maybe in a week, we will see. Till then, you could listen to it, and guess about how well it will measure.
Here are the driver measurements from the 3rd and 4th sessions:
- the 3rd one has raw tweeter and woofers, including off axis (the mid measurement I have messed up). Large room (church). Mic distance 1m, distance to floor 2m+
- the 4th is tw and mid, on axis only, raw and then eq-ed a bit and bfc on mid. there is also LR4 applied. At home, distance to floor/ceiling abt 1.2-1.1m depending on driver. mic distance 60cm.
I came up with some interesting results. Still playing, but here's what I see.
Your tweeter response looks perfect. I made changes to the mid response. It looked pretty good, but the tweeter was perfect, so worked with the mid.
What I did was this. I made an frd of your filtered mid, and tweeter responses.
Then I loaded those filtered responses into my PCD sim software. They added nice, but didn't have a remarkable reverse null..
I noticed that you did not notch the mid peak near 7k, so I added that EQ in the software. I notched it 20dB. The Q is 1. The resulting mid roll-off became 30dB per octave, and the reverse null looked great.
AllenB will fuss about looking at that, so I also looked at the phase. As I added the notch at 7k, they lined up better. Much better. There is no delay on either driver.
So, assuming the phase in the data is accurate, adding a notch at 7k seems to improve things. I also added a touch of EQ at 1.7k. 2dB with a Q of 3.
Note that I did not change the settings for measurement distance in PCD. That could have an effect since you measured close, and midway between drivers. I can look into that later.
On the phase graph, the blue woofer phase still shows. I tried to remove it for clarity, but could not for some reason.
Your tweeter response looks perfect. I made changes to the mid response. It looked pretty good, but the tweeter was perfect, so worked with the mid.
What I did was this. I made an frd of your filtered mid, and tweeter responses.
Then I loaded those filtered responses into my PCD sim software. They added nice, but didn't have a remarkable reverse null..
I noticed that you did not notch the mid peak near 7k, so I added that EQ in the software. I notched it 20dB. The Q is 1. The resulting mid roll-off became 30dB per octave, and the reverse null looked great.
AllenB will fuss about looking at that, so I also looked at the phase. As I added the notch at 7k, they lined up better. Much better. There is no delay on either driver.
So, assuming the phase in the data is accurate, adding a notch at 7k seems to improve things. I also added a touch of EQ at 1.7k. 2dB with a Q of 3.
Note that I did not change the settings for measurement distance in PCD. That could have an effect since you measured close, and midway between drivers. I can look into that later.
On the phase graph, the blue woofer phase still shows. I tried to remove it for clarity, but could not for some reason.
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Well, that was my finding - no delays at the best null.
The tweeter is recessed into the waveguide by about 12mm (baffle plane to dome top), maybe that provides the luckily matching delay.
I also liked the tweeter response - almost perfectly flat. With the tapering bevels I think directivity and diffraction are very decent, too.
The mid: some of the deviation is definitely the baffle diffraction ripple and the baffle step drop. Not sure if there are any other faults to find and correct. I will try your eq to see how it works.
I also need to integrate the woofers.
Thank you for studying this!
The tweeter is recessed into the waveguide by about 12mm (baffle plane to dome top), maybe that provides the luckily matching delay.
I also liked the tweeter response - almost perfectly flat. With the tapering bevels I think directivity and diffraction are very decent, too.
The mid: some of the deviation is definitely the baffle diffraction ripple and the baffle step drop. Not sure if there are any other faults to find and correct. I will try your eq to see how it works.
I also need to integrate the woofers.
Thank you for studying this!
I have not even thought about 7k on the mid as it is more than an octave above xo. I thought LR4 will push it low enough not to matter. Or even LR8. But I think I heard some people advise to clean the drivers to two octaves out of the xo. Is this the reasoning for what you are doing at 7k? Or is there another specific reason?
I would also have never thought of a 20dB notch. How did you decide on that depth?
I would also have never thought of a 20dB notch. How did you decide on that depth?
Breakup is never good to hear, even if it's down a ways. Initially, I notched it about 6dB just to make the roll-off better. Then I played with delays, and didn't find much improvement. So then I started looking at the phase. It didn't seem to change much with different delays. Then I played with the amount of EQ for the notch. The more I added, the better the phase matched. I figured the software would stop at -12dB, but it kept going. Next I looked at how steep the roll-off became. Basically 5th order. It was time for lunch, so I posted what I found. I suspect that a 5th order filter might also work, but it might not have the same initial roll-off.
Eight order probably would not benefit from the notch, unless you were crossing above 4k maybe.
Keep in mind that the phase may match at one location better than another. I think you are Ok even without the notch, but reducing the breakup 20dB has to be an improvement in clarity.
When I measure passive speakers, I measure for the reverse null at several mic heights to see if it's like I want it.
Eight order probably would not benefit from the notch, unless you were crossing above 4k maybe.
Keep in mind that the phase may match at one location better than another. I think you are Ok even without the notch, but reducing the breakup 20dB has to be an improvement in clarity.
When I measure passive speakers, I measure for the reverse null at several mic heights to see if it's like I want it.
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