Which speaker to replace Dunlavy SC-V?

Sean, as you probably know I am in complete agreement with you on just about everything stated above. The one area, I'm not so sure about is the issue re: Dunlavy's and inconsistent bass. I have noticed this on occasion, but not always. I think uneven ceilings had more to do with that, in those cases that it did. I wonder if the Dunlavy's might actually produce better bass due to their design. I can't help wondering if by having the top woofers reflecting from different distances against different textures and structures than the bottom woofers, spreads out the effect of boundry lobing, actually evening things out?
I also wonder if John Dunlavy was able to keep his company going and he actually produced the planned digitaly amped, digitaly crossed-over speakers with their "FLAT" baffles if the vertical issue would have been resolved?

Unsound: Obviously, non-symmetrical loading of the woofers "can" create a flatter overall in-room response. Acoustic Research put this to use in their 9 and 90 designs, showing various frequency response results in the manual. Unfortunately, such is typically not the case with the type of design that Dunlavy utilized. Whereas the AR ( and similar designs ) always have some type of loading on the woofers due to proximity to the floor, the Dunlavy's might have the top woofer further from the ceiling than it is from the floor!!!

With that in mind, I have yet to find someone that doesn't think that the Dunlavy's are improved when using some type of baffle extension / "sounding board" near the top woofer. One can even fine tune the amount of reinforcement / frequency of cancellation by experimenting with the size / angle / location of the baffle extension. Due to their low Q "over-damped" design, the lack of room reinforcement can REALLY make the Dunlavy's seem like they are lacking in low frequency output. Making use of the aforementioned baffle extension can not only improve bass extension, but also apparent bass weight. When you can increase both extension and output without negatively affecting transient characteristics, it's typically a good thing.

The baffle extension can either be mounted from the ceiling down or from the top of the speaker up. Obviously, mounting it to the top of the speaker makes the design more versatile, as you can now position the speaker without having to go through the hassle of re-positioning the ceiling mounted baffle extension. This might not seem important as one would think that they could position the speaker optimally and then mount the extension to the ceiling, but when you install the extension, it will also alter the room loading characteristics / tonal balance. In turn, this may change optimum placement characteristics slightly.

Baffle extensions are a "trick" that can also be put to great use with small stand mounted monitors to increase low frequency output. Some people refer to this type of baffle extension as a "baffle beard" when used on stand mounts, as it can resemble a long hanging beard that is pitched slightly forward. Sean
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Sean,

The DAL V's might NOT be a narrow dispersion "design" but they do throw out a narrow dispersion pattern, this is well known being quite senstive to adjustments of toe in. As I stated, this is not ideal for HT where a broader dispersion pattern and a larger sweetspot is more desirable. They are still undeniably a fantastic speaker and I have never heard anyone call their bass response inconsistent.

Due to the way that Dunlavy treated the baffle, the dispersion on this design IS more limited horizontally than a more conventional MTM design. Having said that, HT systems typically benefit from such a design as the viewer / listener is presented with a more defined left / center / right image. Spatial cues are more realistic and there is less blurring. This is especially true when the speakers are improperly spaced i.e. too close together as is found with most HT installs.

Other than that, most speakers are quite sensitive to toe-in. Being FAR more linear in output than the mass majority of designs on the market, the Dunlavy's simply reveal tonal imbalances in much quicker fashion. As such, errors in ANY part of the system / installation are displayed quite evidently.

If one HAS to run major amounts of toe-in with this speaker, my OPINION ( and that's all that it is ) is that the speakers are set up too wide and / or the listening position is less than optimal. Either that or there are other tonal / frequency response errors being commited elsewhere in the system. By toeing them in drastically, the Dunlavy's are being asked to compensate for these losses via "beaming" more high frequency information directly at the ears of the listener. Sean
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Sean,
I agree that a single listener will benefit from narrow dispersion speakers in HT when in the sweetspot, but my thinking is that most HT should be designed so that several people can enjoy a movie together.

IMHO, the use of narrow dispersion speakers for HT will yield a less balanced surround sound experience than wide dispersion speakers, particularly for those seated furthest from the sweetspot.