Following on from here:
Does anyone have a zoomed impedance response (or log scale) between 500-2KHz
Does anyone know if the rear cup can be removed?
Hats off to @silverD for his waveguide. Now I have a suspicion (but no evidence yet) that the midrange amplitude response and harmonic distortion could be further improved with a modified rear cup.
Cursory look indicates the rear cup is glued.
This is the 7600, but it is the same driver it just has a more of a waveguide faceplate.
A bit of hot air gun later…
do tell!
I’m happy to share the waveguide STL, but I’m in no way an expert. I have yet to make progress on the build with the DM-7500.
If I am not mistaken I think Thanh is trying to get one of us to heat gun our DM7500’s to remove the cup - too cold here and don’t have a heat gun . . .
To be clear, I’m not trying to talk anyone else into doing it. I’m trying to talk myself out of the being the first idiot to try it. I’ll only even consider it once mine arrives and I can inspect the glue line properly.
I found a pair for a reasonable price from a trusted distributor…
Guys, Don’t waste your time and money on the DM7500 - Go with the DM7600 instead!!
I just replaced the DM7500’s in my mid field 3 way monitor mini towers tonight and the DM7600’s are much warmer and detailed XO’d from 600 Hz @ BW-48db/oct to 3500 Hz LR-48db/oct - exact same XO settings as the DM7500 - (DM7600’s are right out of the box though - no burn-in done yet). The directivity problems I was blaming on the tweeter (HiVi RT1.3) are mostly gone now in my weird basement room.
Off axis is MUCH smoother and even as I walk back and forth - vertical dispersion is MUCH better too!! DM7500’s are too trebly - DM7600’s have the missing depth/guts that were previously missing.
Hi-hats and snare have far more guts now - from 6 ~ 8 ft away standing in the sweet spot . . . .
Anyone want these DM7500’S ??
1/2 price plus shipping via Paypal . . .
Thanks for the report. Now I’m happier that I’ve got a new pair of DM7600s on the shelf.
Where did you find a DM7600? They’ve been out of stock on hivi’s website every time I went to look for them. I’m looking at some JR from a different forum linked on Aliexpress… kinda nervous and weighing them against Part’s Express’ Morel CAM 558 (MDM 55 with a round faceplate, parts express exclusive) … It’s a 2 inch dome, but its a 2 inch dome that dome aficionados seem to respect. The difference is 20 bucks and not being able to return the Hivi’s to the seller if/when I find out they’re production rejects being resold. >.<
You found the link I suspect but this is where I bought the DM7600’s –> https://www.aliexpress.us/item/3256806560872392.html?spm=a2g0o.order_list.order_list_main.5.6a6318024UT67Q&gatewayAdapt=glo2usa
Mind you that I am using DSP so I don’t pay much attention to impedance mismatches as I can adjust FR to my ears/space.
It was a good transaction for me.
Let us know what you do or don’t and how it turns out or not, Mr. Dichotomist !
Hey, silverD - how is your DM7500 in a printed wave-guide going?
Care to elaborate?
Bet it is just as good as the DM7600 . . .
Hi Steve,
I haven’t done anything more since my post. I’ll share the STL in a few minutes, but I’m also willing to ship out my prints to someone with DM-7500 who can take better measurements than I.
DM-7500 Waveguide final.txt (1.8 MB)
Change from .txt to .stl
Thanks for the feedback and gracious distribution of your efforts silver-dude!
If you’ve already made good 3D prints, I’m happy to accept them.
But might costs a small fortune to ship anything Down Under (Australia- post/zip code 3000) no thanks to recent world events.
I’m setup to take good polar measurements (eg. higher SPL handling microphones with low self noise/distortion) for high sensitivity/larger Sd drivers. My main limitation is time; due to recent home renovations priorities.
An alternative if you share your trusted print material/settings and online 3D printer and I could give it a go…
I still haven’t bought these. Got a new job so speakering was put on the back burner. ^^ I was wondering if we had any measurements for the 7600 on vs off axis performance anywhere. JR (or was it you steeve?) posted DM 7500 on and off axis measurements that indicated around 1.2-1.5kHz the 7500 had a sort wider response than may be desirable. Which may or may not have been part of what you were hearing in them. I’m not sure.
I’m still looking for a tweeter to pair with these. A Morel CAT 308 was suggested, but that was to go with the MDM55, which I was considering subbing out with this HiVi DM7600. . . The woofer though is pretty much locked in. A Dayton 10’’ SiG270-4. This driver should let me have substantial overlap with the dome all the way up to 1.2-1.5kHz, so should let me employ a very gentle crossover handoff. I’m hoping the tweeter can also have a lower cutoff comfortably around 1.5Khz, again, to overlap with the dome and have a smooth directivity transition as well as the output reinforcement that comes from that. Hopefully allowing extremely low distortion at moderate to high output levels. You know, faking the vanishingly low distortion of Volt/ATC/Bliesma domes.
I also plan to FS compensate the dome if I can do it for under ~$100 per dome. That should improve their low frequency performance even more. As well as using Purifi’s passive compensation technique to suppress distortion from the Dayton’s cone breakup (because passive electronics can provide electrical dampening qualities that reduce distortion in ways equalization can’t) Those would both be good if you planned on using this dome in Hivi’s crossover range of > 350Hz & < 6.5kHz
I know that seems off topic but I would say implementation details like that coupled with that printed waveguide would help to level this dome’s capabilities up a touch. . . and, you know, validate my thoughts and stuff~ 
