Hello all,
I'm looking over the feedback on the 40s over time and the lack of midbass and the surfeit of low bass seems to be a common feedback/criticism of this speaker. I used to have a HUGE acoustical space in my last apartment, and I never agreed with this feedback while I had my 40's in that space.
But I recently moved to a new space, still a large space, but slightly different, and surprise (surprise) I do hear too much low bass and not enough low bass! I try everything, putty, pots, position, everything. Out of desperation I decide to swap woofers, putting the mid-woofer in the bottom position and the low bass woofer in the top position, and suddenly I've hit audio bliss.
My question is for other RM40 owners - how many of you have tried this? And what are your results?
Tyson,
The RM40 is not just "ONE" speaker model, but many. By that I mean since its introduction in 2002, Brian has slowly and surely made many changes. Some of these changes directly affected the areas you are talking about.
One of which was to move the Woofer crossover from 166hz to around 250-280hz.
The other was switching from using two "different" Bass Drivers, and instead using the same drivers with differing magnetization.
Another was the "Vitrification" of the Passive Radiator.
The RM40 being such a large speaker, it "couples" with the room boundaries to a greater degree than a smaller speaker. This means that having the woofers "closer" to those boundaries will cause "effects".
Having the lower woofer and PR closer to the floor will generally reinforce the low bass due to the boundary effect.
Having the Midbass Driver higher will "generally" provide a clearer and more detailed presentation of the subtle upper bass detail that many never hear.
However, the proximity to the ceiling, the material of the ceiling, and other factors like room dimensions can all effect the overall sound.
To that end, I, with my first pair of RM40s placed a few record albums on top of my RM40s so that they stuck out over the upper woofer 4-6". I called this the "Sonic Director" and its purpose, was to "Direct" Midbass Energy that would be reflecting off the ceiling more toward the listener. Since it was so close to the driver, it didn't have any deleterious affect on the sound.
This was a simple solution for those who had low ceilings, or ceilings that caused "bad reflections".
If you are in a room that creates a bass imbalance (with the emphasis on "low bass") moving (swapping) the woofs will reduce the low bass (I think Brian said by 3db). It will also cause the then close to the floor "midbass" driver to be reinforced by floor reflection and reinforcement.
So it is a mechanical manipulation of the FR of the speaker/room interaction to more fit your space.
If one is extemely "adventurous"
and has a strong neighbor, you can try simply turning the whole speaker "upside down". This would also "lower" the speaker by a couple inches (since there is no slot and PR on the top) so you may have to "slump down" a bit to see if it helps your room. If it makes a dramatic (positive) change, then swapping the woofers is not too hard. But do know that in most cases, it will reduce low bass and increase midbass.
