jtnfoley Posted January 2, 2010 Share Posted January 2, 2010 I'm going to start my HII canter-channel design with the goal of lowest profile possible, while maintaining HII responsiveness. I believe this will require matching the interior volume as closely as possible to the original HII box design. According to the HII specs page, the outside timensions are: Height Width Depth 21.375 15.5 13.25 Since they're MDF, I assume they are 3/4" material thickness plus veneer. Ignoring the veneer, my working inside dimensions are 19.875x14x11.75 for an interior volume of about 3269.5 in^3,or 1.89 ft^3. My questions are simple (for now [] ) Is there any center-channel benefit from deviating from the design volume? If so, what volume? Is side-firing or down-firing the woof going to significantly reduce efficacy as a center? Quote Link to comment Share on other sites More sharing options...
WMcD Posted January 2, 2010 Share Posted January 2, 2010 About the volume, I'm not sure. It might be possible to get a bit more bass extension with a larger volume. Someone will have run the TS parameters. But I wouldn't fool with it unless you get some confirmation. About side or downfiring the woofer. I suspect this issue comes to the fore in an effort to reduce the height of the cabinet which will otherwise be the height of the 12 inch woofer. The crossover to the mid horn in 700 Hz and the woofer has to work from their on down to some freq for good performance. In HT receivers the "small" setting is about 70 Hz. So the question is, will tilting the woofer mess up the on axis response between 700 Hz and 70 Hz. More specifically, at what freq does it get messed up and at how much tilt. I'm looking at a spec sheet for an EVM 15 in a square cabinet. Going 90 degrees off axis at 800 Hz you're about 18 dB down from on axis.With a 12 inch it might be a little less' but not much. A smaller radiator should be less directional. So, I'm suspecting that you might tilt the woofer 45 degrees in some cabinet design if you really, really, really have to. The polars for the 15 inch is 8 dB down at 45 degrees. Overall, I say to just live with the 12 inch cabinet height dictated by the forward facing woofer. Wm McD Another issue is just how little bass response is needed from a center channel. A buddy of mine is running a tweeter and K-400. To me, it works but is a bit screechy even with K-Horns at the sides. Another interesting question is just Quote Link to comment Share on other sites More sharing options...
russ69 Posted January 3, 2010 Share Posted January 3, 2010 Redesigning a classic, you're a brave man............ a lot of info comes off the woofer, my guess is that it needs to be facing forward and if that is the case it will be hard to shave more than an inch off the width (height on it's side). Thanx, Russ Quote Link to comment Share on other sites More sharing options...
jtnfoley Posted January 3, 2010 Author Share Posted January 3, 2010 Redesigning a classic, you're a brave man............ a lot of info comes off the woofer, my guess is that it needs to be facing forward and if that is the case it will be hard to shave more than an inch off the width (height on it's side). Thanx, Russ That's what I'm finding! As a learning experience more than anything, I've been playing with WinISD and discovered an 8" driver currently for sale at PE that matches the performance of HII K-24-K almost exactly with an acceptably sized (sealed) box. Gains track to within a percent or two (estimated) from <10 Hz to 1kHz, with SPL 1dB below that of the K-24-K. Unfortnately this is a 12 ohm driver so I may have to play with the crossover OR find another driver with a similar performance at 8 ohms. Quote Link to comment Share on other sites More sharing options...
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