Looks fairly good, I'd play around to fix this small dent in 2kHz, maybe damper value or damper position. Same with 8kHz, you've got 10dB drop which is quite substantial if you ask me, here I'd increase the cap to 3 or 4uF. In the current set up you have a nice L-shaped signature.

OK, so, in theory the SWFK should be in the same polarity as ED meaning that the cap should go to the left pad not the right as on the scheme, BUT, here's where it gets tricky depending on the tubing size and length, and ultimately a sound preference you might want to keep the polarity as is...

2x22uF in parallel together will make 44uF :) (and 2x22uF in series would make 11uF) so you can solder 2 22uF together and you have 40. As for the drawing 1 is identical to 2. every single time someone mentions wiring the tweeters and phase this exact question pops up, I anticipated it trying...

Yes, and impedance at the specific frequency, not the DC value, unless you are dealing with Planar or DD where Z=Rdc for 99% cases. No In most cases the R is not necessary. You need to consider electrical phase of the driver and how it fits into the rest of the design, in most of the cases...

Lol, you think I'm doing any math haha, use online calculators, you just have to know impedance plot of the driver, which you could technically measure yourself. Yeah of course you can do that, just again be mindful of the crossover frequency - in that configuration 6-8kHz could be a sweet-spot...

You need to do some calculations to understand where you are first, otherwise you are going in blind. 22uF 2389 (single, no center cap) gives you cut off fr at 830Hz with center tap that becomes roughly 1.6kHz ( in reality probably closer to 1kHz as the impedance rises and is not linear) 2.2uF...

Lose the center tap - connect normally - this will give you more mids as your crossover will move an octave down. 2389 is already very low impedance, in parallel dual that impedance is halved further with center tap that impedance is halved once again, you are looking at 2.5 ohms at 500Hz if my...

In this config, if the black squares are caps, the top driver is connected with a 2nd order crossover (12dB/oct), this might not be the most optimal unless the goal is to boost only the highest frequencies in a narrow range

LOL thanks for believing in me

clearly there's sound leak, you just have to find where.

From what I see you have a front-volume vent going to the top, this is why you got no bass, you need to partially block the vent with damper and vent the back volume of the DD at the same time

Glad you like our Hybrid 3Pro :)

Thank you Marcus for a wonderful review! Whaaaat! hahaha! That's AMAZING guys!

Actually HeadphoneCompany should have FIBAE 7U demo, reach out to Thomas. They don't list 7U on the website but do have a demo.

https://eu.mouser.com/ProductDetail/Knowles/RDI-33438-000?qs=BJlw7L4Cy79a%252BXw%2FeRvFfw%3D%3D https://www.digikey.com/en/products/filter/speakers/156?s=N4IgjCBcoLQCxVAYygMwIYBsDOBTANCAG4B2aWehA9lANohxwDsATAJwgC6hADgC5QQIAL6igA