Would a Rythmik still benefit from an MBM?

[jbjb]

Just wondering, what frequencies would be encompassed by the term "mid bass" in relation to subs?

[monomer]

Just wondering, what frequencies would be encompassed by the term "mid bass" in relation to subs?

Ah, such a simple question but alas the answer is not really well defined. There have been whole threads over on the AVSForum dedicated to arguing over what exact freq range does mid-bass refer to. Car audio guys give a totally different range than home audio guys, and audiophiles and trained musicians seem to have different ideas than home theater aficionados. So take this with a grain of salt but when I use the term in relation to subwoofers I'm thinking along the lines of a 40-80Hz range... its the freq range that is often credited with providing the "slam" or visceral effects of bass when played loudly.

[jbjb]

Thanks for your thoughts on what mid bass means. In terms of "slam" I always thought the area between 30-50Hz was key.

So then what is the role of the deep bass like 15-30Hz?

[monomer]

Thanks for your thoughts on what mid bass means. In terms of "slam" I always thought the area between 30-50Hz was key.

So then what is the role of the deep bass like 15-30Hz?

The precise freq range for "slam" has also been highly debated (again there are threads on other forums dedicated just to arguing the point).
My MBM is tuned to roll-off below 50Hz and I have it crossed at 80Hz. If I want "slam" all I have to do is turn it up and you can literally feel the bass passing through your body. However that upsets the balance of bass... it's great for a thrill ride but more often a bit too juvenile for my tastes. My tastes appear more oriented to seeking a musical balance across the whole freq spectrum with the bottomline of having things sound REAL as opposed to just pursuing giggles. Deep bass (below 30Hz) is for making pant legs flap and vibrating the foundations of your house and pissing-off your neighbors.... seriously, deep bass is for movie explosions, UFO landings, monster stomps, earthquakes and other such movie sound effects. For me, above 30Hz is for musical instruments and voices... however I will admit that with certain movie sound effects, unnaturally boosting the mid-bass region can be fun by making you jump at the sound of gunfire and vibrating certain parts of your body. I wish Rythmik subs would have the damping on a remote control so I could change the tuning just for those 'fun' movies.

[monomer]

Just a quick follow-up...
After living with these subs in various configurations for awhile I've got to say, for me, I feel the answer to my original question is "Yes, a Rythmik will still benefit from the addition of an MBM". I purchased a second Rythmik two weeks ago as I love what it does below 50Hz, its just amazing how accurate and clear those low frequencies can sound coming from these direct-servos but alas I prefer having the (sealed) MBM punch above 50Hz. The good news is I find the blend is completely seamless between the MBM and the Rythmiks and I believe I now have the best of everything from 80Hz on down... with the goal here being 'keeping it REAL'.

[Mcpanse]

How did you install your two Rythmiks and your MBM?

[monomer]

How did you install your two Rythmiks and your MBM?

Not sure what kind of answer you're looking for here but...
The short story is... After a LOT of attempts at different configurations I finally found a good blend by literally replacing the VTF-2 with one of the Rythmiks. IOWs, I have one F12 co-located with the MBM. This F12 has its cross-over set to what approximates a 40Hz on the dial. The two are stacked in totem-pole fashion about a foot to the inside of and slightly behind the left main and the other F12 is located in the mirrored position in relation to the right main and its XO is at max (IOWs the Onkyo controls the bass management). This arrangement makes phasing equidistant to all listening positions for all three subs. My room is almost but not quite exactly symmetrical, which is why I think this arrangement seems to work out so well. I had to level balance the F12 / MBM in relation to each other first and then balance that combo to the other F12... BTW none of this was easy to do. In the end, it does sound great... However I would feel better if I had another MBM to co-locate with the other F12 and then I could also drop its XO to 40Hz... to be honest, I just don't want to pay the full price for another MBM right now, so I'm patiently waiting for a used sealed MBM to come up for sale somewhere (or if I can find a really cheap ported version I'd pay the additional $70 to ship and get the amp modified). Right now time is on my side as I'm really quite happy with the way everything is sounding ...so I'm feeling like I can afford to be patient and wait for a good deal on a used MBM to turn up.

[Mcpanse]

Thanks Monomer. A very useful post for folks who might want to go this route.

Did you connect the MBM to the F12's line outs, or visa versa? How did you handle the crossover settings? That's what I was getting at with my question above. Sorry for the confusion.

[monomer]

...Did you connect the MBM to the F12's line outs, or visa versa? How did you handle the crossover settings? That's what I was getting at with my question above. Sorry for the confusion.

I used lotsa splitters to go from the single sub pre-out on my receiver to feeding each sub's inputs (both L and R). The MBM has a natural roll-off below 50Hz so the Onkyo handles the bass management on the upper end (I'm using 80Hz at the Onkyo)... so the challenge becomes setting the F12's XO appropriately. I should have used REW to help but instead I just used test tones and a SPL meter to find the XO point that produced a relatively flat transition from ~30-60Hz and it happened to end up being with a XO setting approximately corresponding to 40Hz on the dial. I guess that sounds right since XOs are not brick walls but slopes and when you sum the output of two slopes together you're better off measuring the total SPL output to prevent unnatural peaks at the XO point. Anyway, that's what I've done so far. In the near future when I get the time I will probably break out REW and fine tune the whole set-up but for now, its sounding really good.

[monomer]

Latest iteration (for the last month now) has both my F12s crossed ~40Hz and using the single MBM to handle the mid-bass range solo. This time I employed REW to select a cross-over point that provides a smooth transition with the MBM's roll-off and also used it to help set the X-O points identical between the two Rythmiks. I'm nearly to the point of breaking down and purchasing another MBM to co-locate with the other F12, even though currently the sound is well-balanced and FR reasonably flat with adequate headroom... (I guess must be the money is just burning a hole in my pocket).