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

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I have acquired this 8" TB Neo sub for free, and I can't figure out what to do with it. I'd be fine using it in my car or as a small home sub, but whenever I use software to model a box for it it gives me a port so long that the box required to hold it would defeat the whole purpose of a small but powerful driver like this. I am not that experienced with using those programs so i could be doing something wrong. I have searched both here and on Google on gotten nothing but dead-end threads with the same question as me, but nobody seems to answer. Anybody got any ideas?

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-833
 
For home use, how about a .6 cu. ft. box with this port.

Build the box out of 3/4" MDF to be 9"x16"x13"

Mount the port and the woofer on the 9x16 side.

Use the maximum length of the port, which is 11 inches. The end of the flared port will be 1.25" from the back wall. This will extend the acoustic length of the port to about 14"

In a .6 cu ft. box w/ 2" x 14" port you get a tuning frequency of about 30hz.

Assuming your plate amplifier has a rumble filter (2nd order highpass at 25hz), at 120 watts air velcity in the port will be 37 ft/sec. Not ideal, but the heavily flared port will prevent any kind of chuffing.

If you want to build the subwoofer amplifier into the box, make the box taller. 9"x20"x13" could also work.

Dan
 
Your problem is that the Vas of the drive unit is quite small, and Xmax fairly large. To get a vent that does not chuff due to the large excursion of the drive unit, it needs to be wide, which means it needs to be long because of the small box. The answer is a passive radiator for best efficiency, or use the box sealed with some EQ and trade SPL.
 
There are lots of posts around the net about folks using these, so a search is probably worthwhile. (also search on the W8-740C which is a ceramic magnet version with similar tradeoffs).

The nutshell summary is that you have 4 basic choices, in rough order of practicality:
1) sealed box in the car, where cabin gain compensates for the high F3 rolloff. You could try an eq'd sealed box in the home, but there isn't that much volume displacement to work with.
2) Passive radiator. Only practical way to get a useful small box for home use
3) Tuba. I haven't built one (yet - TT on the slate when I can get back in the shop), but they're amazing looking designs if you have space for a big box
4) Get a few more of the same drivers and run them in the same box, which brings the box size up to the point where the ports aren't quite so silly. Maybe not that cost-effective though, as a single Dayton RS series sub driver costs about the same as 3 more of the TB's.
 
#4 doesn't solve the problem, because as you add drivers the port area and length requirements increase.

Paul - the solution I suggested will work very well with the 75wrms amplifier. If you want to use it in your car, I'd highly recommend against ported. Instead, go with a .25 cu. ft. sealed enclosure. The QTS of .55 will sound great in a car.

Dan
 
I built this odd contraption for the MCM 55-2421, a cheaper clone of the W8-740C. I choose this as I had the left over parts. The enclosure is a tube with a 7.25" i.d.. If memory serves, the thing is about 30" long. It has a pvc port with a 3" i.d., about 27" long. The driver fires into the bottom. The port is held in with a closet fitting, that is filed by hand to be very flared. Obviously, it's not the ideal solution in terms of resonances, but it works pretty well. It models -3db a little below 40hz, and it pretty flat to 35hz in room. The port chuffs easily with 30-35hz sine waves. I gave it to my step brother. With the typical stuff he listens to, it sounds great. There isn't enough content down there for the chuffing to be audible. It also isn't the most efficient use of space, but it fits decently at the very front of his trunk. It's a cheap and easy build. It's an easy way to get a long enough port into a small enough enclosure.

This is my least favorite implemenation of three I've tried for this driver. However, the 8ft transmission line isn't going to work in your car. (I no longer needed it, so I cut it down to build the ported enclosure.) I also built a passive radiator system for a friend. Its tiny and works great. Its an E.B.S. that reaches 30hz easily, but must be crossed over below 60hz. Unfortunately, the nice, cheap P.R. I used isn't available anymore. I haven't seen another cheap P.R. that has enough mass to tune suitably and enough Xmax to use the drivers capabilities. I think it would be silly to pay twice as much for the P.R. as for the driver.

I know the TB Neo is a bit differnet, but I thought I might give you some ideas. The Fitzmaurice AutoTuba would be great if you have the room and can build it. Note however, that he uses a little sealed box in his own trunk, as he, like most of us, doesn't need that much bass in his car.

Whatever you choose, I predict you'll be very happy with that driver in your car.

pj
 

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I think I have enough scrap wood around here to try it in both a .25 enclosure in the car and a bigger one in the house and see where it is most valuable. I'm already thinking it will please my wife to have it in her car, except I was just about to put a 15" free air sub in there with some EQ for ***** and giggles. I'd better ask her before I do that anyways. Thanks for the input everybody.
 
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.
 

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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.
 
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.
 
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.
 
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