Same set up again, this time for an SX like you have. This was only a 15 though, almost the same box as the SE. They both work great for music/movies in boxes like this. Just use enough bracing inside the enclosure and built it solid. I also like the ports on the front and bottom always, it is a preference of mine. It always seems to make the sound more predicable to me, maybe I have just had bad luck with the port in other places, but I have built maybe 50 or more subs like this for home audio and have always had good luck doing it this way. I like to have the cabinets sprayed with Line-X by the way...
Attachments
You are going to hear lots of different opinions on here, all them right of course....
You will be fine, if you built the box a little smaller and less vent you would also be fine....
Just shoot for a flat alignment with low tuning like you planned and build a stout box, you will be happy I'm sure...
You will be fine, if you built the box a little smaller and less vent you would also be fine....
Just shoot for a flat alignment with low tuning like you planned and build a stout box, you will be happy I'm sure...
To remove the tendency of the big long port turning this box into a TL (which it still is -- length is ~10; which is getting you a primary resonance on the order of of just under 30 Hz), you will need to divide the port into a couple or more ports. It also wouldn't hurt to make the port smaller (& therefore shorter) as long as you don't get small enuff to start having problems with port chuffing.
Or you could just model it as a TL in MJK and do a much more accurate sim -- because once you build this you will have little capability to retune the port and you'll have burned thru a lot of plywood.
I'd also run the braces the other way -- they will be much more effective. And i always situate a brace to tightly couple the magnet to the entire box.
dave
Or you could just model it as a TL in MJK and do a much more accurate sim -- because once you build this you will have little capability to retune the port and you'll have burned thru a lot of plywood.
I'd also run the braces the other way -- they will be much more effective. And i always situate a brace to tightly couple the magnet to the entire box.
dave
I bet you would be very happy with the results of that design. That SX 18 will hammer out some serious lows in that box. Your port dimensions are almost exactly the same as my XXX 18 enclosures I am currently running for my H/T right now. They were just about right on the money with my calculations and they are absolutely devasting, I don't think I could have done better........
Attachments
If you fancy something a bit different, here's one idea -a mass loaded tapped horn (not the TD style - driver front vents to the room).
Total line length is 120in, folded in half for a 60in tall box. Internal width = 19in. Depth of the sealed end = 6.0in. 1:4 taper ratio, depth of the 'open' end is 24in. In the open end is a 5in diameter 8 3.5in long vent. You can either have it firing vertically (suggested) or horizontally, as close to the end of the line as possible. Driver is mounted 32.75in down from the open end. Line the box from the sealed end to just above the driver on opposing faces with 1in acoustic fiberglass.
Anechoic FR attached. To this you can add the usual approximate +3db from 100 - 40Hz & +6db below that figure. Impedance curve is nearly flat, excursion is 1mm total for 1w / 1m at 15Hz.
Total line length is 120in, folded in half for a 60in tall box. Internal width = 19in. Depth of the sealed end = 6.0in. 1:4 taper ratio, depth of the 'open' end is 24in. In the open end is a 5in diameter 8 3.5in long vent. You can either have it firing vertically (suggested) or horizontally, as close to the end of the line as possible. Driver is mounted 32.75in down from the open end. Line the box from the sealed end to just above the driver on opposing faces with 1in acoustic fiberglass.
Anechoic FR attached. To this you can add the usual approximate +3db from 100 - 40Hz & +6db below that figure. Impedance curve is nearly flat, excursion is 1mm total for 1w / 1m at 15Hz.
Attachments
ßart West-VL. said:You mean; you have no windows!?!
I honestly don't listen to it that loud these days, once and a while when I have had a few drinks maybe.... And then I think the neighbors pass it off as the train that runs near our town every hour.......
As a side not, and this isn't meant as Off Topic, please delete this post if you see fit mods, but is there any Audio Groups anywhere near Ramstein? I have been at a loss searching on the web.....
wasted911 said:
Badly. Drawing is not exactly my strong point. Side-on view. Total line length is 120in, folded in half, as you can see, for a 60in tall box. Narrow bit is 6in deep, wide bit 24in deep (cabinet is 19in wide). The vent is 5in in diameter & 3.5in long, firing upward in this case, though if you want to move it so it fires horizontally, be my guest, so long as you keep it as close as possible to that end. Line the box with damping material from the narrow end all the way down that half of the line, & up the 2nd half of the line to just above the driver, the centre of which is mounted 37.75in down from the wide end.
Attachments
I think your vent is unnecessarily huge. Dual 6" round x 36" long ports that are heavily flared in 12.5 cu ft. will give you the tuning you want.
You could get these, and extend them with 6" PVC.
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=268-354
I also think you should reconsider the shape of your box. Take a look at the Thor subwoofer. The woofer is mounted so mechanical energy travels through the walls rather than flexing the front baffle.
http://www.linkwitzlab.com/thor-intro.htm
Consider a front baffle that is 20" wide and 30" tall. Mount the driver and ports on the front. Make the box deep enough to get you the volume you need, and accommodate the 36" long ports.
Dan
You could get these, and extend them with 6" PVC.
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=268-354
I also think you should reconsider the shape of your box. Take a look at the Thor subwoofer. The woofer is mounted so mechanical energy travels through the walls rather than flexing the front baffle.
http://www.linkwitzlab.com/thor-intro.htm
Consider a front baffle that is 20" wide and 30" tall. Mount the driver and ports on the front. Make the box deep enough to get you the volume you need, and accommodate the 36" long ports.
Dan
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.