[Tyson]

Hello again,
Yesterday I spent some time swapping my low bass woofers (bottom) to the top, and the midwoofers from the top to the bottom on my RM40's.  The results in my room are revelatory, the speakers sounds much faster, cleaner, clearer, and hugely improved midbass response (actual "punch" and snap are evident in the bass). 

In my room, before the swap, I had a measurable broad-band dip in the upper bass, it was about 10 db down compared to the low bass and the midrange.  This might be an artifact for my room, as I didn't notice this in my last home, in a much larger, more open space.  My suspicion is that with the speakers fairly close to the room's corners, there's more of a reinforcement of the low bass from 3 planes (floor, plus 2 walls), and less room boost for the midwoofer that isn't corner loaded. 

Anyway, I've heard consistent feedback from people over the years that the 40's are mid-bass shy, for maybe the same reasons I've observed in my own space.  If this is so, flipping the woofers seems to address it very nicely, and would seem a reasonable option to offer from the factory. 

[ctviggen]

With the new mid-bass drivers, I'd say the RM40s have excellent midbass.  Now, I personally think they're shy on low bass. 

[Tyson]

I have the new midwoofers, and my pair were certainly not shy on low bass, they were 10 db higher than the upper bass, all the way down to 20hz!!  20hz-100hz were all around 90db on test tones w/an SPL meter, and 125hz-500hz was recessed at 80db in comparison, and everything above 500hz was at 90db.  It was clearly audible in normal listening too, which is what caused me to break out the old SPL meter and test tones in the first place.  Now, after the swap, it is audibly flatter across the frequency range.

Likely it was a room issue, as I have an odd shaped space that I'm in now, and I'd never heard this frequency anomalies in my previous 2 homes.  Personally I'm just glad a simple driver re-arrangement could result in such a good solution.

[John Casler]

That bass response is a funny animal.

My RM40s have both low and midbass in my room to the point I only use my subs for HT now.

I think brian said that swapping the woofs under most circumstances would reult in the lower bass being about 3db down, but Tyson's experiment shows that his room and placement balance that out.  The close to walls positioning probably reinforces/amplifies the "low" bass, and putting the midwoofer close to the floor creates a better boundary than the ceiling for the midbass.

In the old days, before the midwoofer upgrade, I used a "sonic director" tweak to "direct" the midbass frequencies better than my 9' ceiling, and nearfeild listening angle.

My new RM40s have the midbass upgrade and don't need it.

You could always just turn the whole speaker "upside down" and sit in a chair that is 3" lower to see if it works for you.

[audiochef]

Hi Tyson, welcome back.
In the past it seemed the primary reason others did the switch was because they felt the soundstage  was unrealistically too high. Did you notice any change in this. Although an easy experiment, I've never tempted this myself.

Thanks. Stan

[woodsyi]

I never swapped the woofers.  Since I tri-amp and ask the woofers to do only between 280 and 50, they are quite happy to put out. 

[Tyson]

I always liked the soundstage height that the 40's offered, so that was on an issue at all for me.  In my setup it was strictly a bass imbalance (too much low bass), and the woofer swap has addressed it very nicely.