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Dear Fellow SC IVA owners

Dear SC IVA owners. I recently made some improvements to my SC IVAs that were transforming when all were added up together. I thought I'd share these and hope others contribute to what improvements they have made. 1. Added Sunfire IV subwoofers set at the lowest crossover point and very very low volume. This improved midrange noticeably by opening it up while the bass went a bit deeper. Spread speakers out from each other nearer sides of room so at least 2.5 feet farther from each other with major improvement in detail and clarity. Added symposium ultra platforms under each speaker with Walker points under the platforms. Major improvement again. All of these transformed my sound from very good but slightly cloudy to very clear with even deeper and tighter bass, a scary musicality rare in any component and a top to bottom coherence that this speaker is known for. I hope someone else has had similar success and perhaps some other new tips. All of these improvements except the subwoofers came from suggestions from other Audiogon members.
jonathanhorwich
timlub
2,039 posts
 
Hi Pryso, the wool was strictly diffraction control. I agree with you on the subwoofer points also.
unsound
7,329 posts
 
Pryso, the Dunlavy's also have stepped baffles, in order to maintain proper time alignment.
pryso
1,928 posts
 
Thanks Unsound. There is enough mis-information on the internet without my adding to it. ;-)

Probably what I was thinking of, the Duntech baffle step backs are open on the sides to help dispersion. My recollection is the DAL speaker's sides are not.
timlub
2,039 posts
 
Pryso, you are thinking right. A very basic description would be, Stepped baffle is putting the tweeter behind the same plane of the woofer to align voice coils. (kinda like a stairstep) That is why I called it voice coil alignment in my earlier post, that is stepped baffle. You are actually putting the voice coils in alignment. The idea is that the sound radiates from the same point for correct time alignment of the signal to your ears. The dispersion from the drivers then bounces off the frame of the drivers. The wool felt absorbs part of this to keep the reflections from warping the frequency (defraction). You can also align the signals electronically, this is called stepped baffle compensation for time alignment.
I hope this helps, Tim
unsound
7,329 posts
 
Pryso, I could be mistaken about some of the details, but, John Dunlavy might have made some prototypes(?) of a statement speaker (Magnumns?) that had active digital cross-overs and separate digital amps for each driver in a rather oddly shaped cabinet that appeared to look like 2 triangles mounted upon each other at a single corners that had flat baffles. The digital cross-overs were to electronically correct for the timing issues of the various voice coil depths. Apparently this avoided the cupped horn loading problems of the stepped baffles. I think John Dunlavy was waiting for higher resolution digital devices to become more of a marketable item to make the speakers more reasonably priced. John told me that this was the future of his designs, and he hoped that as the digital technology developed, it could be trickled down to his less expensive products. He believed that the digital technology could cut the costs of the then necessary labor needed to hand match each set of speakers. Unfortunately, poor health took over before he and us could realize the promise of his brilliant ambition.
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