Set up like above for comparo. Hilo LO > TOCOS pot > Parasound Zamp > NegMonitor vs Hilo MO > LSR305 balanced TRS input set for 4dBu
Started going back and forth and went WTF. Vocal on NegMonitor was effed to hell. Tried sitting on some books but it wasn't just the off-axis response. Of course I turn them back vertical and things lock into place. So much for quick switching; have to give each the spotlight and listen
Biggest difference is bass volume. The 305 has a lot more mid bass volume, akin to my OSMT. Sealed cabinet is never going to extend as low. In this case though it's too much given the positioning (rear of cabinet is <9" from wall). I did try pushing down LF trim but it needs more than 2dB. The reason I made mine sealed in the first place
Other than that, it breaks down like this
LSR305
+ More bass punch
+ More vibrant, faster
+/- Hyper-dynamic JBL sound
- Slight artificial tinge on acoustic instruments
- Cuts out some low-level stuff
NegMonitor
+ More precise, more nuanced
+ Bass doesn't overhang
+ Deeper stage, disappears better
+/- More reserved, consistent sound
- Congested lower mids, upperbass
- Less dynamic
Overall I'm fairly happy that I've got the tonal balance pretty close to the 305, considering I know the 305 to be quite flat. The 305's do tend to grate on my ears after a while, for whatever reason. Almost like a technicolor sort of effect. Probably because they're hyper-dynamic with too much port energy. After listening to the 305 for a good part of the day and then going to AB against the NegMonitor, the music really does start to wash over you. I'm so happy that these drivers can be so precise and resolving while still having certain euphonic qualities. A lot of precise and resolving headphones are missing that natural quality or are just straight up fatiguing. I can only hope that adding that additional damping behind the woofer will clean up the lower-mids and add even better blackness. The fact that these are still comparing well in what is essentially a raw cabinet gives me hope.
BTW, the 305 is still way better than any headphone <$1000. Highly recommend for headphone lewsers who are interesting in getting into real hi-fi