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I am in the process of designing and building a system for my home stereo, and my mains will be a two-piece design with hexagonal (or faceted trapezoidal) enclosures simlar to the old Tannoy Definition line (D500, D700, etc.) but with slightly more pronounced facets. I already have the driver that I will use for the mids and up (unless I add a supertweeter later), a pair of 8" dual concentrics by Tannoy. They have a poly cone woofer and a metal dome tweeter firing through the "Tulip" waveguide bored through the polepiece that's good to ~1.4kHz. I've measured T/S parameters for one of them, and the only thing that jumped out at me as somewhat unusual was a very high Qms value of 10.55. (I spoke with a Tannoy rep and he sent me a spec sheet indicating that to be about right.) The current mid-tweet crossover is a bit high, but I'll fix it once I decide on the rest of the parts and start cranking. Lovely as they are, they really need to not be moving much. I've not yet decided on woofers under it, but I'm leaning towards two 10's per side in a sealed enclosure*, operating from ~400Hz down. Budget's an issue, especially with crossover parts to buy (see more below), so I'll find it pretty hard to justify more than $70/woofer right now. I will also be running my current sub (probably), so ultimate LF extension isn't a big deal as long as it goes up cleanly and has an F3 of 60Hz or lower.
Based on those criteria, I've shortlisted the following woofers on paper, though I've not heard any of them. The ordering is random.
-Peerless 830668/SLS10 (I use the SLS8 in my car, don't know if the 10 is available through the usual suspects.)
-Peerless 850146/CSX10 (I've used the HDS205 in a previous home system, and liked it.)
-Dayton RS270 (No experience with the line, but the buzz seems great. Wish PE would post full parameters including Sd, though.)
Before anyone asks, yes I think I'd rather go with two medium-excursion drivers than pay the same for one high excursion driver. I want the efficiency (the Tannoy 2046's are 91dB/2.83V/m) and I want the extra surface area to keep cone movement in my system to the minimum possible. That said, I'm only fishing for ideas now; Darren's given me enough information (1mH inductance, yum - though the xmax Darren quoted me is a lot less than the 20mm figure I read in the 10" 3-way thread here) that any ultimate decision will wait until the Dayton RS subs come out. If that driver will work, then I might well go with one woofer per speaker. It's too bad a 12 will make the enclosures too wide for an acceptable SAF score...
However, the reason I posted this long message here is that I'm considering a C-E filter between the woofers and the dual, probably with some modifications for BSC. My only question on that front right now is that I'm having trouble picturing how physically large and expensive (using "regular" parts, e.g. Dayton or Solen poly caps, air core wire inductors, and Dayton resistors) a ~400Hz 8th order C-E filter of the type used in the speakers designs that have their home here here could get. I've never done a passive (or active, for that matter) filter steeper than 4th order acoustic, and never used a passive that low, either. Can someone give me a ballpark estimate?
*I would like to go dipole/cardoid in the future, but right now I can't afford the cone area I'd need to reproduce Shostakovich 10 in such a speaker. Besides which, 2 or more 15's per side would dominate my current living room to such an extent that I'd likely never again be allowed in it! So for now it's the lowest-Qtc closed boxes I can get away with.
Based on those criteria, I've shortlisted the following woofers on paper, though I've not heard any of them. The ordering is random.
-Peerless 830668/SLS10 (I use the SLS8 in my car, don't know if the 10 is available through the usual suspects.)
-Peerless 850146/CSX10 (I've used the HDS205 in a previous home system, and liked it.)
-Dayton RS270 (No experience with the line, but the buzz seems great. Wish PE would post full parameters including Sd, though.)
Before anyone asks, yes I think I'd rather go with two medium-excursion drivers than pay the same for one high excursion driver. I want the efficiency (the Tannoy 2046's are 91dB/2.83V/m) and I want the extra surface area to keep cone movement in my system to the minimum possible. That said, I'm only fishing for ideas now; Darren's given me enough information (1mH inductance, yum - though the xmax Darren quoted me is a lot less than the 20mm figure I read in the 10" 3-way thread here) that any ultimate decision will wait until the Dayton RS subs come out. If that driver will work, then I might well go with one woofer per speaker. It's too bad a 12 will make the enclosures too wide for an acceptable SAF score...
However, the reason I posted this long message here is that I'm considering a C-E filter between the woofers and the dual, probably with some modifications for BSC. My only question on that front right now is that I'm having trouble picturing how physically large and expensive (using "regular" parts, e.g. Dayton or Solen poly caps, air core wire inductors, and Dayton resistors) a ~400Hz 8th order C-E filter of the type used in the speakers designs that have their home here here could get. I've never done a passive (or active, for that matter) filter steeper than 4th order acoustic, and never used a passive that low, either. Can someone give me a ballpark estimate?
*I would like to go dipole/cardoid in the future, but right now I can't afford the cone area I'd need to reproduce Shostakovich 10 in such a speaker. Besides which, 2 or more 15's per side would dominate my current living room to such an extent that I'd likely never again be allowed in it! So for now it's the lowest-Qtc closed boxes I can get away with.
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