Whats up everyone. I read the majority of posts on subwoofer TLs, but I still have a few questions.
I read about multiple ways of designing a TL from the ground up based loosely on a tuning frequency I would select and the Sd of the driver.
I plan on using two of these:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-460
I want to make 2 TL's As skinny as possible (11.5 inch width) and approximately 54 inches tall.
Depth is not really an issue, although I would like to stay under 18 inches. I want to build out of 3/4 inch MDF.
Is it reasonable to think a TL can be made in these dimensions which will have its -10 dB point below 20 hz?
If so, what design?
If not, how big do I need to go?
I read about multiple ways of designing a TL from the ground up based loosely on a tuning frequency I would select and the Sd of the driver.
I plan on using two of these:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-460
I want to make 2 TL's As skinny as possible (11.5 inch width) and approximately 54 inches tall.
Depth is not really an issue, although I would like to stay under 18 inches. I want to build out of 3/4 inch MDF.
Is it reasonable to think a TL can be made in these dimensions which will have its -10 dB point below 20 hz?
If so, what design?
If not, how big do I need to go?
Greets!
Drivers with a tiny Vas to fit in small cabs typically don't do well in low tuned TLs since its CSA is so small (low gain). To tune it to Fs to get to below 20 Hz requires a ~152" long pipe with only a ~25"^2 CSA, so you should be able to fold it up in the allotted size with a half space ~18 Hz F10 if the specs are reasonably accurate. Tuning this low also shifts its 3rd harmonic down into a sub's BW, so there's basically a 'black hole' in the response from ~70-100 Hz.
GM
Drivers with a tiny Vas to fit in small cabs typically don't do well in low tuned TLs since its CSA is so small (low gain). To tune it to Fs to get to below 20 Hz requires a ~152" long pipe with only a ~25"^2 CSA, so you should be able to fold it up in the allotted size with a half space ~18 Hz F10 if the specs are reasonably accurate. Tuning this low also shifts its 3rd harmonic down into a sub's BW, so there's basically a 'black hole' in the response from ~70-100 Hz.
GM
The hole in response would be perfectly acceptable, since I plan on crossing over to them around 60-80 hz anyways.
Will increase the CSA result in any benefits? Its kind of hard for me to fit a 10 incher that is around 6 inches deep in a 25 inch cross section. Is a CSA of 50 or so possible?
With this line length and CSA is the response flat till what?
Is it possible to go lower without getting alot bigger?
Last question, I swear!
Other than the smaller Vas, is there any other reasons to not use this driver for a TL for low tuning?
Thank You so much!
~Jerick
Will increase the CSA result in any benefits? Its kind of hard for me to fit a 10 incher that is around 6 inches deep in a 25 inch cross section. Is a CSA of 50 or so possible?
With this line length and CSA is the response flat till what?
Is it possible to go lower without getting alot bigger?
Last question, I swear!
Other than the smaller Vas, is there any other reasons to not use this driver for a TL for low tuning?
Thank You so much!
~Jerick
Greets!
You're welcome!
Increasing the CSA will increase peaking at each end of its response. Adding a short section just big/long enough to mount the driver won't affect the response enough to matter. It will just look a bit funky standing proud of the baffle if you don't bother to cosmetically blend it in.
There's nothing in the driver's published specs to indicate it won't work, but there's only one way to find out for sure.
See the first plot. Upping the CSA to 50"^2 and length to 175" looks good to really drive the room modes (2nd plot).
GM
You're welcome!
Increasing the CSA will increase peaking at each end of its response. Adding a short section just big/long enough to mount the driver won't affect the response enough to matter. It will just look a bit funky standing proud of the baffle if you don't bother to cosmetically blend it in.
There's nothing in the driver's published specs to indicate it won't work, but there's only one way to find out for sure.
See the first plot. Upping the CSA to 50"^2 and length to 175" looks good to really drive the room modes (2nd plot).
GM
Attachments
Greets!
I'd start with 60 Hz/4th order since the room's modes are going to chop it all up anyway, so you'll probably need EQ to smooth it out somewhat. The potentially big problems are running out of Xmax if there's not enough room gain and/or they're too far out of spec.
Anyway, a mini-review would be nice.
GM
I'd start with 60 Hz/4th order since the room's modes are going to chop it all up anyway, so you'll probably need EQ to smooth it out somewhat. The potentially big problems are running out of Xmax if there's not enough room gain and/or they're too far out of spec.
Anyway, a mini-review would be nice.
GM
Thanks again GM!
I have started drawing up plans, but I do not know how big to make the end of the line.
I assume it is just the same as the starting, but want to doublecheck.
Will putting a curve at each bend help anything? I have seen it on a few designs, and i think I could easily make it if it will help.
Also, just for fun, are there any other TL geometries that might work better than a straight TL? If anything I would like to compare two types of TL. Maybe Straight versus Tapered or Expanding. (expanding might get too big for even I.)
Other than those few questions, I should be building soon. Won't be testing till I get my 2 plate amps though. I think I am going with the Rythmik Audio 350 Basic.
~Jerick
I have started drawing up plans, but I do not know how big to make the end of the line.
I assume it is just the same as the starting, but want to doublecheck.
Will putting a curve at each bend help anything? I have seen it on a few designs, and i think I could easily make it if it will help.
Also, just for fun, are there any other TL geometries that might work better than a straight TL? If anything I would like to compare two types of TL. Maybe Straight versus Tapered or Expanding. (expanding might get too big for even I.)
Other than those few questions, I should be building soon. Won't be testing till I get my 2 plate amps though. I think I am going with the Rythmik Audio 350 Basic.
~Jerick
Greets!
You're welcome!
This is a simple 1/4 WL pipe, so it has a constant CSA. If it had a forward expansion it would be a horn and if reversed, then a TQWT (aka ML-TQWT, which is more accurate).
Adding curves to better preserve the expansion through the bend only helps its HF BW, so isn't necessary in a limited sub/LF/midbass BW alignment.
An offset driver ML-TQWT will be smoother in the 3rd harmonic - up BW, but this isn't an issue for you so I see no reason to go to the extra effort and increased footprint.
A < 20 Hz basshorn will be huge by most folk's standards even if mass loaded and/or 'tapped', though of course it will have considerably more gain than a straight pipe simply because of its greater Vb.
GM
You're welcome!
This is a simple 1/4 WL pipe, so it has a constant CSA. If it had a forward expansion it would be a horn and if reversed, then a TQWT (aka ML-TQWT, which is more accurate).
Adding curves to better preserve the expansion through the bend only helps its HF BW, so isn't necessary in a limited sub/LF/midbass BW alignment.
An offset driver ML-TQWT will be smoother in the 3rd harmonic - up BW, but this isn't an issue for you so I see no reason to go to the extra effort and increased footprint.
A < 20 Hz basshorn will be huge by most folk's standards even if mass loaded and/or 'tapped', though of course it will have considerably more gain than a straight pipe simply because of its greater Vb.
GM
I see I see. 
So I have two choices now, the CSA of 25 and 152" line
or the CSA of 50 and 175" line.
Now after thinking about your comment about making a larger chamber for the woofer that is at the end of the line, I think I may go with the smaller CSA for an overall smaller box.
Heck, I am so confused I may build them both! Now that I am done with school I have all the time I need.
Last question, could I lengthen the line and keep the CSA down to get the extended shelf like the longer and larger csa of 50 box?
I really like the predicted response of the larger box, but the smaller one is of course smaller and would be nicer to have. I figure I could fit a CSA of 25 line of length of around 190 ". If I can get a larger shelf(preferably flat to 20 hz.) I would like to.
Even if I can't thanks very much for the 2 designs already, and for your excellent explanations. Have a good one.
~Jerick
So I have two choices now, the CSA of 25 and 152" line
or the CSA of 50 and 175" line.
Now after thinking about your comment about making a larger chamber for the woofer that is at the end of the line, I think I may go with the smaller CSA for an overall smaller box.
Heck, I am so confused I may build them both! Now that I am done with school I have all the time I need.
Last question, could I lengthen the line and keep the CSA down to get the extended shelf like the longer and larger csa of 50 box?
I really like the predicted response of the larger box, but the smaller one is of course smaller and would be nicer to have. I figure I could fit a CSA of 25 line of length of around 190 ". If I can get a larger shelf(preferably flat to 20 hz.) I would like to.
Even if I can't thanks very much for the 2 designs already, and for your excellent explanations. Have a good one.
~Jerick
Well Hello Again!
I was just offered an even trade, 2 of the 10" HF subs for 2 12" HO subs found here:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-466
My question, Should I take the trade? Still looking for the lowest flatest extension I can get in a relatively small box; Which is less than 3.5 cu ft.
I was just offered an even trade, 2 of the 10" HF subs for 2 12" HO subs found here:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-466
My question, Should I take the trade? Still looking for the lowest flatest extension I can get in a relatively small box; Which is less than 3.5 cu ft.
Alright, so just to double check, the line is 175 inches end loaded with a CSA of 50 inches square?
Should I measure the line length from the center of the driver, or from the end of its chamber used to allow it to fit?
What frequency do you think I should filter this at?
And will stuffing even out the upper response, or is it not worth it, In other words, just cut the sub before that garbage up top.
Thanks Very Much GM!
Should I measure the line length from the center of the driver, or from the end of its chamber used to allow it to fit?
What frequency do you think I should filter this at?
And will stuffing even out the upper response, or is it not worth it, In other words, just cut the sub before that garbage up top.
Thanks Very Much GM!
Greets!
That's what I posted........ The sim assumes from the end of the pipe, which would be the driver's mounting flange, but an inch or two either way on a 175" nominal length isn't going to matter.
The XO would be whatever blends best in-room, though you'll probably want it to be below the huge dip with a steep slope to quickly attenuate its upper harmonics.
Any stuffing will roll off its LF gain too, so only use it if it's too boomy in-room.
You're welcome! Looking forward to a review!
GM
That's what I posted........ The sim assumes from the end of the pipe, which would be the driver's mounting flange, but an inch or two either way on a 175" nominal length isn't going to matter.
The XO would be whatever blends best in-room, though you'll probably want it to be below the huge dip with a steep slope to quickly attenuate its upper harmonics.
Any stuffing will roll off its LF gain too, so only use it if it's too boomy in-room.
You're welcome! Looking forward to a review!
GM
I really like the folding used in the Jensen Transflex, which would be easy to scale to whatever length and CSA you want. It may be easier to make you 12's fit too. Then you could try also try it as the Transflex and as a straight TL.
GM,
Do you have an opinion about the Transflex design with the front radiation and TL terminus sharing the terminus at the end of the line?
GM,
Do you have an opinion about the Transflex design with the front radiation and TL terminus sharing the terminus at the end of the line?
The Transflex is just soo Tall. I would have to set it up in the corner, or lay them on their side in the front and back or sides of the room.
This size, I can scoot them around anywhere, lay them under things, whatever.
I may try a transflex design though, to see how it performs agaisnt one of these...
The question is, what do you think about the end of the line I pictured above? Is it acceptable as long as it is the same CSA?
This size, I can scoot them around anywhere, lay them under things, whatever.
I may try a transflex design though, to see how it performs agaisnt one of these...
The question is, what do you think about the end of the line I pictured above? Is it acceptable as long as it is the same CSA?
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