Bass Response on Dunlavy SC-IVa

The problem is the variation in the reaction of the woofers to the floor and the ceiling. You have a large differential in boundary effects. The woofer on top is much further from the ceiling than the woofer on the bottom is from the floor. So you probably have a bass suckout of about 6db at 60 to 70 hz at ear height at your listening position. This is where much of the hit bass is on most recordings. Some geometric panels {and not soft} to act as a lens to refocus lost energy back at your chair would greatly enhance phase and frequency. Tom

I never got the bass right either. On the IVA or the V's. They are one huge speaker which makes it a lot more difficult to get right and live with

I have a possible solution, which is worth trying.
Try listening to the room.
Play one speaker, using a low frequency test tone, with the speaker in a 'probable' final,location.
Walk around the room, and find where the 'hot spots' of good bass are. This will give you an idea as to where the potential locations of the listeners chair might be. The key is to extrapolate that in to the 3 diminsional puzzle that setting up an audio system presents.
When setting up a system in a problematic room, I always try to get a 'fix' on the room's sound.
Best

While i can dig up the facts / figures on this speaker, does anybody happen to have the crossover points handy?

I agree with what Tom / Audiotweak is saying in that the woofers are non-symmetrically loading into the room. Since all rooms have various ceiling heights, the results with this type of speaker will vary from installation to installation. Then again, this is true ( to varying extents ) with any design that raises the woofer(s) up above floor level / very bottom of the cabinet. That's because boundary effects are somewhat "set in stone" with a design of this type.

One will also encounter this with woofers that are stacked vertically but somewhat spaced apart from the other. This is especially true if the bottom woofer is already measurably up off of the floor. The larger Vienna Acoustics speakers suffer from this quite noticeably and even the reviewer in Stereophile commented on this. If i remember correctly, he went so far as to say that they were the hardest speakers that he's ever had to deal with in terms of placement.

Having said that, the staggered woofer array can be put to great use, but one would have to fine tune the spacing between the drivers and the crossover points for the individual listening area that the speakers would be used in. By "tuning" the output range of one woofer where the nulls of the other woofer(s) are occuring, the response sums to something that is much flatter overall. This is probably what Dunlavy was trying to accomplish, but without knowing the ceiling height and the distance from the side walls and how far they are pulled out into the room, there is no way to optimize the design.

Having said that, Dunlavy gives pretty specific placement suggestions for these speakers that seems to work quite well, but if you can't follow them, there are other methods that may work for your given installation. Only problem is, this requires a LOT of moving & listening, which large speakers like this aren't exactly easy to work with. Sean
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Try this: Move your listening chair,place a ladder where your chair use to be. Play a constant test tone at about 60hz. Climb the ladder up to ceiling height, make reference of the 60hz tone with either an spl meter or your audio memory. As you come down the ladder at each step make another measurement and record the output, do this until you reach about 2 feet from the floor. Now after you have done this move the ladder, re-install your chair at the original position and take the same measurement at ear level {38to40in.}..At ear level you will have a 6 to 8 db suckout..in contrast to the floor and ceiling measurements.The frequency of the suckout maybe 50 to 80 hz so your reference tone may vary slightly.While doing any of these tests do not touch the volume control. ..You can mitigate some of the phase cancelation by moving your ceiling or by building an acoustic lens attached to the ceiling ..Tom