JBL M2 versus 4367 Shootout

[Bugal1998]

24hz is the -3db spec with 18hz at -10db
A little room gain could show more or less depending.
With dual 18" drivers a little EQ should get you whatever you desire.

Indeed, 18hz is what I'm hoping for in the finished space... We shall see. So far they've acted like there's a brick wall filter at 25hz, even with no high pass filter activated.

Until I see otherwise, I can only report to other interested parties what I've actually experienced.

 

[Sal1950]

Indeed, 18hz is what I'm hoping for in the finished space... We shall see. So far they've acted like there's a brick wall filter at 25hz, even with no high pass filter activated.

What sort of DRC do you have at had?
Seems I remember you discussing Dirac a bit?

 

[Bugal1998]

What sort of DRC do you have at had?
Seems I remember you discussing Dirac a bit?

Yes, Dirac. With a JBL SDP-75 (Trinnov Room Optimizer) sitting in a box waiting... Patiently... For my room to be ready for the speaker/electronics installation.

 

[Sal1950]

Yes, Dirac. With a JBL SDP-75 (Trinnov Room Optimizer) sitting in a box waiting... Patiently... For my room to be ready for the speaker/electronics installation.

Great, I'm sure you'll be able to work it out with that gear in the new room.
I have a feeling the roadblock may be a positioning issue if you haven't played with it in this old room.
Have fun.

 

[Bugal1998]

Great, I'm sure you'll be able to work it out with that gear in the new room.
I have a feeling the roadblock may be a positioning issue if you haven't played with it in this old room.
Have fun.

Thanks, Sal. Eyes, fingers, and toes are crossed that you're correct!

I had concrete walls and floor in the temp space and wasn't able to adjust the position(s) of the subs. Some measurements suggest a series of closely overlapping room modes may have caused a deep and broad null at the lower end of their response. But close mic measurements showed a similarly steep drop-off, so we wait to see. I have four 24" IB subs to bring in wherever the quad corner placed 5628s rolloff, and I'm hoping the overlap is no higher than 18hz since that's the lowest mode in the new room.

 

[Sal1950]

I have four 24" IB subs to bring in

wherever the quad corner placed 5628s rolloff

and you have 4 5628's ?

I gotta see this rig in the new room when it's up.
The Force Be With You.

 

[Bugal1998]

and you have 4 5628's ?

I gotta see this rig in the new room when it's up.
The Force Be With You.

Yeah... I swear I'm not crazy though. I bought four 5628s for the same cost as the lowest price I could find anywhere for two JBL Sub18s (regardless of origin). So eight 18" drivers for the price of two with similar extension?! It was a no brainer since I had plenty of space.

The IB-24's are there to take-over wherever the 5628s rolloff. I had a 4.5'x13.5'x7.5' space that needed to be walled off to optimize the room acoustics, so I added a horizontally opposed mounting baffle with two 24s on each side. Again, why waste the existing space that could easily be used as a giant infra-sonic sub?!

I should have unlimited dynamics with a smooth frequency response in the audible range, and excellent infra-sonic extension, all without taxing the drivers in the audible range with infra-sonic bass.

I'll make a build thread when the room is finally up and running.

 

[Adi777]

for some odd reasons perhaps only known to psychologists, the American Audiophiles have all but shunned JBL. It doesn't register.

For Polish audiophiles, JBL is also treated moderately positively. I was reading opinions about the JBL Everest DD67000. If I remember correctly, boring, technical, dry, maybe also raw sound.

I'll make a build thread when the room is finally up and running.

How big is your room?

 

[Bugal1998]

How big is your room?

TLDR: Acoustically, 28’6”L x 19’4”W x 8’5”H (8.7m x 5.9m x 2.6m) finished inside dimensions

Long answer…

32'6"L (longest dimension, but rear wall is irregular) x 19'4"W x 8’5”H (9.9m x 5.9m x 2.6m) finished inside dimensions

After turning the irregularity in the rear of the room into a large (~400cu. Ft. Or 11,300 cu.liters) sealed subwoofer, then acoustically, that results in a rectangular room that’s 28’6” L by 19’4” W finished inside dimensions. I’m using 2’4” of both the front and back walls for site-built bass traps that provide mid and high frequency reflection.

Visually the finished space will be 24’L x 19’4”W

All walls and ceilings are decoupled from the house structure for bass performance and sound isolation, and the rear ~10’ of the room floor is a riser engineered as an additional large bass trap.