Modding the Zu Omen MKII

Hello, I saw this post and recently purchased the Zu Omen DW’s with Jupiter cap upgrade and I’m very interested in the 475-be tweeter replacement for the stock ones in the DW speakers.  I’ve been reading the post and are these the parts I’d need to replace the stock tweeters?
1.  475-be tweeters 
2.  Lpad using Mills wirewound resitstors [I have no idea what these are]
3.  P-Audio PC-20 Adaptor - 1" Small Format Bolt On to 1" Screw-in Horn [How many will I need] 

I have never done a DIY before, but I’m trying to reinvent myself by telling my foolish self that I could do it! I’d appreciate any help with the parts I need to replace the stock tweeters with the Radian 475-be tweeters. Could I fit the ZU 2" HFL-1 TWEETER LENS in the DW’s and are these lens compatible with 475-be tweeters? Sorry for all these questions.

@kevinjkim, Congrats on picking up the Omen DW’s with the Jupiter cap upgrade! I’ve enjoyed mine (with the Clarity caps) for a couple years and decided to upgrade to the Radian 475 beryllium tweeter over the summer (along with variety of other mods). A list of the mods I performed:

• Upgraded to Radian 475 beryllium tweeter
• New high-pass filter network with Duelund tinned copper caps and Path Audio resistors
• Upgraded to Zu’s 103ND full-range driver
• Changed all screws and mounting hardware to t-nuts
• Applied sound-deadening material to interior
• Epoxied dowels laterally and between the full-range driver and tweeter
• Added 2-inch thick butcher block platforms hard-mounted with stainless steel set screws

I tried to document the process as much as I could here:

https://www.dropbox.com/sh/pktaalffodhoxnf/AABfkg37-ALobyUkX6HhbQWWa?dl=0

And I put together a list of parts I used here:

https://docs.google.com/document/d/1lGO5Ovrh5U3NazCCaO3-H_cO2Lhy7sGjlG8bLZan-gw/edit?usp=sharing

If this is your first DIY project, putting together the L-pad (or high-pass filter network) might be the hardest part since that requires soldering. Refer to the parts list for the values of the resistors I used (credit goes to @zuangbro for the values). I verified the resistor values from page 12 of Zu’s upgrade manual for the Druid IV (note that the schematic uses a 16-ohm Radian tweeter, whereas I used an 8-ohm version):

https://static1.squarespace.com/static/51dd8a95e4b0ff2f7c9874ae/t/51fc5f88e4b05ae014fc4eb4/1375494024810/UK-Druid-4-13.pdf

Being that the Radian 475 is a much heavier tweeter than the stock Eminence ASD:1001 (6.4 lbs vs 2 lbs) I would highly recommend upgrading the mounting hardware for the tweeter lens. I believe Zu doesn’t recommend removing the tweeter lens at all because the stock wood screws will strip the threads in the MDF cabinet, which is what happened to one of the screws on mine. Upgrading the mounting hardware to t-nuts, lock nuts, and new button head stainless steel screws will make the tweeter lens/cabinet interface rock solid.

The 2-inch tweeter lens won’t work on the Omens. With a lot of work it might, but then you’d have to use the much heavier Radian 850, which is a 16 pound tweeter. I used the P.Audio PC35 flange adapter to pair the Radian 475 to the Omen’s stock tweeter lens and it works seamlessly.

Overall I had a blast modding the Dirty Weekends, definitely one of the highlights to an otherwise difficult year. It was a great summertime shelter-in-place project, and as we go into winter with more lockdowns likely, I hope more DW owners will get the modding itch.

Btw, on *that other* audio marketplace website, there’s someone selling a pair of Radian 475 berylliums. Make a deal and save some bucks! Good luck!

OH~MG 
Dear, SlowLearner28

Thank you so much!  I’m going to check up on all these parts and start this project!  Thank you so much for the detail information!  I’ll keep ya posted!  I’m going to save all the pics on my iPad and start looking up on parts!  A lot of things to study! 

@kevinjkim So glad I can be of help! I made comments on some of the photos on dropbox, providing more context and detail where I could. Feel free to ask questions. DIY will change your life. :)

Just chiming in here. I today finished up all the mods that @slowlearner28 mentioned. First, several months ago, I inserted the dowel bracers and applied the auto sound deadner. That tightened up the bass somewhat.

Last month I replaced the stock drivers with the 103ND. That brought greater clarity and dynamics to the mid-range.

Over the past few days I installed the Radian 475 aluminum tweeters (I couldn’t afford to spring for the beryllium versions). I did an A/B test with installing a Radian in one speaker and going back and forth with the balance control on my amp. It seemed to my ears that the new tweeter adds more presence to the high end. I have to listen a bit more - there’s definitely a difference, but I can’t pin down what it is yet, as dumb as that sounds. Today I put the remaining Radian tweeter into the other speaker.

Some advice:

If you can afford it, I’d go with the Acoustic X coating instead of the auto mat stuff. I’m sure they both worth fine, but I think applying the coating might be easier and cover every square inch. The auto-mat stuff is heavy, can get in the way of the dowels, and takes a while to flatten completely out with a roller. I know Zu uses the Acoustic X type stuff. 

Be very careful with installing the t-nuts if you’re adding those to the mix. Make sure the t-nut cones fit properly in the drill holes and accept the screws without locking up before you put them in the cabinet. I had one t-nut get stripped or something when I screwed in the 103ND and it was a huge headache - the screw got 3/4 of the way down the t-nut but then would turn continually without tightening or loosening. I had to get a pair of bolt cutters to snap the screw head off and ended up scratching the aluminum perimeter ring that goes over the driver. I had a similar problem with one of the smaller t-nuts for the tweeter, but at least that time I had learned my lesson and tried them all out before installing them. Frankly, the t-nut installation was by far the biggest PIA of this project.

Finally, the theaded steel studs that came with my tweeter-to-dome adapter were 1/2" too long. They stuck so far out of the tweeter that I couldn’t screw the Radians into the Zu tweeter dome. You need to get 1/4-20 threaded studs that are 1" long, something like these.

Anyway, the project is now finished. I’m hoping to put in some serious listening time in the next day or so.