well, we do know that two of them in a largish floorstanding MLTL can certainly deliver the goods to at least the low 40s
The problem with that w6 is it is small with 13mm of travel. I'd personally use something with high Sd and less travel to get the same Vd. They're only 83db efficient and part of what I like in a Fast is you can use the woofer to BSC. So if we use an 85db MA driver, I'd want something that is at least 88db to get me at least 3db BSC.
If you used two of them, you're getting there. Relying on xmax to get you bass isn't something I'd normally practice, unless tight on space as said before. This is basically what Klippel is all about. As the cone moves out, things get non-linear. So a larger woofer traveling less, will inherently stay more linear. I think I've actually seen Klippel data on that w6, but I can't remember if it was good or bad. So there again, using two cuts down on the required travel.*
Higher Sd usually means more efficient, which means less travel. Cause you could say, it doesn't matter if there is an spl mismatch, I'm using a minidsp so I'll just boost the woofer. Ya but then you'll be really using that 13mm of travel and, well, I just don't think it'll sound as good as these incrideble MA drivers
It makes sense what you're saying. Perhaps I'd be better off with larger and more sensitive drivers in a sealed enclosure. I found three woofers I like:
SB Acoustics SB23NRXS45-8 (8")
f3 50Hz sealed
Vb 38 liters ~1.34 cu ft (Qtc = 0.707)
88.5 dB 1W/1m
6.5mm Xmax
60W power handling
Morel CAW 938 (9")
f3 39Hz sealed
Vb 81 liters ~2.86 cu ft (Qtc = 0.707)
86dB 1W/1m
4.75mm Xmax
150W power handling
Scan-Speak 26W/8534G00 (10")
f3 41Hz sealed
Vb 70 liters or ~2.47 cu ft (Qtc = 0.707)
89dB 1W/1m
6mm Xmax
150W power handling
I guess I could boost the low end a bit with some EQ, although the SB Acoustics' relatively low power handling would prevent too much boost.
How would you say such woofers in sealed boxes would compare to the W6-1139 in vented?
For me the problem with above drivers (and most others I've seen so far) is the box size requirements. That's what I like about the W6-1139s - their ability to go low in a small enclosures. Part of my design goal is to make a shallow and smallish cabinet. I'm now thinking that perhaps an aperiodic enclosure could be the way to go. What are your thoughts on this?
And just to repeat my previous question: Is a sealed+vented combination really a big no-go in FAST? Even with a XO of say 300Hz?
I hope to put a CA22RNX in a BR cabinet this weekend. May not have time but hopefully I can throw it together. Its not going to go super low, but should give me an idea of what a compliment will sound like with the A7.3. I have heard it already with a standalone sub and liked the result, so i am moving in this direction. My main entry level choices are between Dayton and Peerless woofers of the 10" variety.
WinISD is all I have at present. I would love to have the newer MJK worksheets, but no Mathcad.
jeff
would be nice, but I wouldn't fret if it only has 0 or 180 - when used as intended the woofers will be a fraction of a wavelength of the XO frequency from the rear horn mouth of the FH3
Zia,
I'm not to sure about the stuffing, I usually try and fluff it up. But I'm no pro on box design. My thinking comes from fluid mechanics. Air can be thought of as a fluid, and it'll see friction along the sides of the box, but not in the middle. However, what I just stated isn't totally correct, but my knowledge ends there.
Dimensions will depends on the xo frequency. If 300hz for example, that's just over 1m wavelength. So I'd stay with dims less than 1m. And dims of uneveness are always good. Shouldn't be hard with 27L. For the same reason, I'd say flush mounting is not necessary.
I'm not to sure about the stuffing, I usually try and fluff it up. But I'm no pro on box design. My thinking comes from fluid mechanics. Air can be thought of as a fluid, and it'll see friction along the sides of the box, but not in the middle. However, what I just stated isn't totally correct, but my knowledge ends there.
Dimensions will depends on the xo frequency. If 300hz for example, that's just over 1m wavelength. So I'd stay with dims less than 1m. And dims of uneveness are always good. Shouldn't be hard with 27L. For the same reason, I'd say flush mounting is not necessary.
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WinISD is all I have at present. I would love to have the newer MJK worksheets, but no Mathcad.
jeff
Jeff,
Thanks - I just tried WinISD - f3 is 45 Hz or 35 Hz for 30 ltr?
Dave and experts, a few questions on how to go about building this box:
1. Should I line all inside panels or only top, one side wall, and back wall for the woof box? Any fluff I need to put in?
2. Do you advise any particular dimension/ratio for the box (as long as I keep total volume the same)?
3. Any need to flush-mount the EL166?
-Zia
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Soren, I don't see anything wrong with a sealed MA over a ported woofer. I plan to do it
Again, if space is a premium, perhaps the TB isn't bad. I just don't like the thought of a cone moving 13mm at 40hz while also producing a 300hz signal. That's a subwoofer job. Those are nice woofs you mentioned, but pricier. Mind you, our pricing may be different. See if anyone else has some thoughts. I thought more people would chime in. I threw out the large SB's as an option. I think they're pretty ultimate, but they won't suite everyone, including me ($).
Again, if space is a premium, perhaps the TB isn't bad. I just don't like the thought of a cone moving 13mm at 40hz while also producing a 300hz signal. That's a subwoofer job. Those are nice woofs you mentioned, but pricier. Mind you, our pricing may be different. See if anyone else has some thoughts. I thought more people would chime in. I threw out the large SB's as an option. I think they're pretty ultimate, but they won't suite everyone, including me ($).
Tux,
Thanks for your quick response. I made a few changes to my post - and in the process I deleted and reposted - so guess your post came in before mine that way.
If I choose 28 ltr which is about 1 cu.ft., I can go for 12" x 12" x 12" - IIRC there's a design for SDX-7 done by Dave which is like a cube... but these are all even sides. I can keep volume same and do 14.5"x12"x10". The port length is roughly 8 inches.
Thanks for your quick response. I made a few changes to my post - and in the process I deleted and reposted - so guess your post came in before mine that way.
If I choose 28 ltr which is about 1 cu.ft., I can go for 12" x 12" x 12" - IIRC there's a design for SDX-7 done by Dave which is like a cube... but these are all even sides. I can keep volume same and do 14.5"x12"x10". The port length is roughly 8 inches.
Soren, I don't see anything wrong with a sealed MA over a ported woofer. I plan to do it
Again, if space is a premium, perhaps the TB isn't bad. I just don't like the thought of a cone moving 13mm at 40hz while also producing a 300hz signal. That's a subwoofer job.
Tux,
The TBs Soren referred to earlier are subwoofers, and high xmax ones. Might be good for a tapped horn too - IIRC Chris661 is using them in THs.
Yes, I think also lilmike on avsforum has a TH that can use it. Like you said, it's a subwoofer. Not sure it'll be happy playing at 300hz, no matter what the spec sheet says. I think Soren will need to make a design compromise. Bigger, or accept less than ideal. At least with the mini, he can xo at 200hz later if he chooses
I'm pretty sure it was 35Hz, but I can't post an image, as I'm on my wife's laptop. My CAD box has a dead PS at the moment. My plot for the EL166 looked different than yours. I used QB3 alignment.
jeff
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