The two major ones indicate you have some kind of reflex loading 😊 but there's no relation with the free air resonance of the woofer (there almost never is, unless you go Open Baffle). The theory is that your reflex tuning is either at the impedance minimum between the two or at phase = 0 degrees. Somewhere between 37 and 40Hz. The peak at 130Hz could relate to an internal dimension of 75cm or 150cm, standing wave issue in the enclosure. The one at 650Hz could be a cone breakup or a standing wave too. Since you won't use the woofer at 650Hz, only the first standing wave is worth addressing to.
Mark, I have a 6 inch port 11 inches long. That is the low 30's (if I am correct) The woofer free air resonance is 22hz. So is there anything to worry about regarding the zma? regarding the 75cm dimension. I will check but the cabinet is 40 inch high, and the midrange enclosure may reside at 29 inches so maybe that is causing an issue??
True devotees to reflex systems might argue both peaks should be equally high. I'm not one of them. The issue at 130Hz (the midrange enclosure could be at play) could be fixed by placing a sheet of acoustic foam 4-5cm horizontal, between port and woofer, but that's just an educated guess.
i could put the foam on eith of these two locations the bottom level is between woofer and port, the higher level is between port and mid enclosure. Note that port is not shown but you may be able to sneak a peak at the flare attached to the front panel.
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so I put the foam in and it damped the second peak a bit, I thought I saved a jpg of it but apparently I didnt. It didnt do much, next I will damp the undersides of the top of the cabinet and midrange enclosure. BTW something very bizarre happened; Just for the hell of it I decided to do another frd of the woofer. And the impulse is the inverse of yesterday and the set up has not changed, WTF!
There are two ways to accidentally invert polarity. One is in the wiring, another one is to flip it in software if there's an INV button.
have not changed the wiring and I would not even know where the invert button is on Omnimic lol
Ok so I started all over. I made sure I am fully/adequately padded inside the enclosure. All bolt holes secured with fasteners and I redid the zma and frd and impulse measurements. going to try to upload the snapshots here. I am struggling and if there is anyone out there that can spend some phone time I would be grateful. I have a bunch of questions.... Sim is not going well
