What can I do with this 8" TB sub without a 100 foot long port? - Page 2

ckwase · 20th February 2007, 01:13 PM

I built this box orginally for the tb w6-1139, although at the moment there is an elemental designs Eu-700 in it which performs baiscally the same. A slightly larger box would probably work for the 8 inch version.

Bill F. · 21st February 2007, 09:11 PM

Specs look like a promising candidate for a compact 30Hz tapped horn. William Cowan has plans on his DIY Website. Dead easy.

zobsky · 23rd February 2007, 08:10 PM

Quote:

Originally posted by Bill F.
Specs look like a promising candidate for a compact 30Hz tapped horn. William Cowan has plans on his DIY Website. Dead easy.

Funny, I was thinking of the same thing today (I have an extra unit of MCM driver mentioned a few posts earlier). I also have an auto-tuba running with the MCM driver that works well

audiosteve · 26th February 2007, 09:48 PM

I've been wrestling with trying to figure out how to use this woofer myself. I bought it based on its appearance and an assumption that it would easily work great in a conventional ported design. Not so. Stupid me. Model twice, buy once. I have since been modeling a number of designs including passive radiators.
The first respone to this thread with the 2x11" round flared port looks good but the port velocity is also on the high side and could be problematic. There is no conventional round port possible that would have acceptable port velocities and that would not require a huge length. I also cannot find a passive radiator with a good enough xmax and small enough size that also has characteristics (even with added mass) yielding a flat enough response.
It is looking very much like CKWASE is on to something with his type of design. My models are telling me that a 1/2 cubic foot enclosure together with a rectangular folded port of 1x8 inches and 32" length will yield a compact design with a relativey flat response, an F3 of of 34 Hz and workable port velocity. Not bad for a reasonably priced and compact sub to be used in the office.
Wife permitting, I will start building this weekend. Does anyone else see any problems with this type of design or have a better idea?
BTW, I am using Winisd Pro Alpha for the models.

audiosteve · 17th September 2007, 04:57 AM

It has been quite a while since I first chimed in on this thread, but my hectic schedule has finally given me enough time to build the subwoofer. I opted to go with Owli's basic idea and am pleased I did so.
The overall dimensions are slightly different but the end result is probably very close to what he suggested.

The External dimensions are 9.5"w x 13.5"h x 13.75" d using 3/4" MDF. After subtracting for port, amplifier and driver volumes, the net internal volume is 15.5 l (948 in^2). Sides, top and bottom get foam pads for damping.

It uses a Tang Band 1363-SA 8" woofer, Dayton (Parts Express) SA-100 amp and a 2" x 12" Precision Port flared on both ends (net effective length = 11"). with these box dimensions and with the port flare inset into the cabinet, the port is positioned so the internal opening is about 1 1/2" from the back wall in order to extend the effective length. Both port flanges had to undergo some creative trimming in order to squeeze into the limited baffle space.
But nothing affected the appearance. The hole for the port leaves the edge of the outer flange right at the bottom edge of the cabinet.

The results are VERY satisfying. WinIsd says that F3 is a about 32.5 Hz and, after listening, I have no reason to doubt that.

I made this for my office stereo and it sounds great. I'm very happy with the results. If anyone is considering a compact 8" sub for small to medium spaces, I wouldn't hesitate to recommend this one.

Right now it is unfinished. I couldn't wait to listen. I still need to veneer the cabinet and make a nice grill for it. Maybe in a few more weeks.

audiosteve · 17th September 2007, 05:13 AM

One other note to follow up re the sub I just built. IF you made the box 1/2" taller it would only alter the volume about 3% and would not affect the the response much at all. winISD verifies this. But it would probably allow you to forgo trimming the external port flange. BTW, the trimming is on the large perpendicular part of the flange to allow it to clear the bottom panel. Nothing that shows is trimmed. On the inside port you will probably still have to trim the flange a bit. The bottom edge of the flange is cut off (a secant for you geometrically inclined folks) to allow it to sit flush with the bottom panel.

17th September 2007, 04:57 AM	#15
audiosteve diyAudio Member Join Date: May 2004 Location: Niwot, CO	It has been quite a while since I first chimed in on this thread, but my hectic schedule has finally given me enough time to build the subwoofer. I opted to go with Owli's basic idea and am pleased I did so. The overall dimensions are slightly different but the end result is probably very close to what he suggested. The External dimensions are 9.5"w x 13.5"h x 13.75" d using 3/4" MDF. After subtracting for port, amplifier and driver volumes, the net internal volume is 15.5 l (948 in^2). Sides, top and bottom get foam pads for damping. It uses a Tang Band 1363-SA 8" woofer, Dayton (Parts Express) SA-100 amp and a 2" x 12" Precision Port flared on both ends (net effective length = 11"). with these box dimensions and with the port flare inset into the cabinet, the port is positioned so the internal opening is about 1 1/2" from the back wall in order to extend the effective length. Both port flanges had to undergo some creative trimming in order to squeeze into the limited baffle space. But nothing affected the appearance. The hole for the port leaves the edge of the outer flange right at the bottom edge of the cabinet. The results are VERY satisfying. WinIsd says that F3 is a about 32.5 Hz and, after listening, I have no reason to doubt that. I made this for my office stereo and it sounds great. I'm very happy with the results. If anyone is considering a compact 8" sub for small to medium spaces, I wouldn't hesitate to recommend this one. Right now it is unfinished. I couldn't wait to listen. I still need to veneer the cabinet and make a nice grill for it. Maybe in a few more weeks. __________________ Nihilism is best done by professionals.

17th September 2007, 05:13 AM	#16
audiosteve diyAudio Member Join Date: May 2004 Location: Niwot, CO	One other note to follow up re the sub I just built. IF you made the box 1/2" taller it would only alter the volume about 3% and would not affect the the response much at all. winISD verifies this. But it would probably allow you to forgo trimming the external port flange. BTW, the trimming is on the large perpendicular part of the flange to allow it to clear the bottom panel. Nothing that shows is trimmed. On the inside port you will probably still have to trim the flange a bit. The bottom edge of the flange is cut off (a secant for you geometrically inclined folks) to allow it to sit flush with the bottom panel. __________________ Nihilism is best done by professionals.

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21st February 2007, 09:11 PM	#12
Bill F. diyAudio Member Join Date: Nov 2001 Location: SW MI	Specs look like a promising candidate for a compact 30Hz tapped horn. William Cowan has plans on his DIY Website. Dead easy.

26th February 2007, 09:48 PM	#14
audiosteve diyAudio Member Join Date: May 2004 Location: Niwot, CO	I've been wrestling with trying to figure out how to use this woofer myself. I bought it based on its appearance and an assumption that it would easily work great in a conventional ported design. Not so. Stupid me. Model twice, buy once. I have since been modeling a number of designs including passive radiators. The first respone to this thread with the 2x11" round flared port looks good but the port velocity is also on the high side and could be problematic. There is no conventional round port possible that would have acceptable port velocities and that would not require a huge length. I also cannot find a passive radiator with a good enough xmax and small enough size that also has characteristics (even with added mass) yielding a flat enough response. It is looking very much like CKWASE is on to something with his type of design. My models are telling me that a 1/2 cubic foot enclosure together with a rectangular folded port of 1x8 inches and 32" length will yield a compact design with a relativey flat response, an F3 of of 34 Hz and workable port velocity. Not bad for a reasonably priced and compact sub to be used in the office. Wife permitting, I will start building this weekend. Does anyone else see any problems with this type of design or have a better idea? BTW, I am using Winisd Pro Alpha for the models.