Help Designing TL

[h22lude]

I am currently trying to design a TL enclosure but am having quite a few bumps along the way as far as understanding how to come up with dimensions. I have built many sealed and ported enclosures successfully.

I have already spent quite a bit of time at the tlinespeakers.org and quarter-wave.com and still do not understand how to fully calculate enclosure specs for a TL.

If anyone could help me get going in the right direction I would greatly appreciate it.

I need help understanding how to calculate line length and how do you measure the line length of the box? is it from the speaker opening all the way to the port end?

And after calculating the line length how do you determine the box height and line width.

Does tapering have a big advantage? Should the box end up having a specific volume in the end?

Sorry for so many questions i'm just really interested in this box design and would like to learn to build my first oen so i can experiment from there. Thanks for your time!

My driver specs are:
Model: 05C154
Nominal Impedance(Ohms): 4
SPL dB 1W/1M: 90.2
Displacement, cc: 3260
Displacement, cu.in.: 198.7
Hole cutout, in dia: 13 7/8
Mounting Depth, in.: 7 3/8
Revc: 3.32
VC Inductance, mH: 3.44
Sd, m3: 0.0856
BL: 15.32
Vas, Liters: 272.329
Vas, CuFt: 9.62
Moving Mass , oz.: 7.38
Fs:21.68
Qms: 11.2
Qes: 0.397
Qts: 0.383
Peak Power Handling, watts: 500
EXmax, mm: 11.53

 

[planet10]

One thing i'll say right off the bat is that the TL will be BIG (i guess to be expected for a 15")

1st thing to do is pop the parameters into Martin's tables, this will give you an idea.

The higher the taper the smaller the box (in general). The taper helps improve the terminus low pass function meaning that you can get away with less damping and get more bass out of it.

You will get pretty good results right out of the tables but if you want to play further you need to play with the TL in Martin's software.

dave

 

[h22lude]

Okay thanks for the response that helps alot ill definately be tapering than. The tables your referring to are the one's i have to buy right?? Will the tables help me out substantially with what im trying to do? I just wasn't sure if they would help me with what i needed and did not want to waste my money.. Thanks!!

 

[planet10]

The tables are free... the software costs a very modest amount.

http://www.quarter-wave.com/TLs/TL_Theory.html

near the bottom.

dave

 

[bjorno]

If anyone could help me get going in the right direction I would greatly appreciate it.

Hi,

FYI: An example simulation of many possible where the line length is kept short: 1(2)

b

1(2)

 

[bjorno]

2(2)

 

[h22lude]

Okay thanks planet10 and bjorno! That definately got my wheels moving again.. Ill keep looking further into these tables and see what problems i run into. Thanks again!

 

[bjorno]

Hi,

Discard attachment 1(2) here above which now is updated.
Correcting a mistake when cut and paste the FR plots: See the picture 1(1).

b

 

[h22lude]

Wow so that definately ended up being a LOT bigger than I thought. What numbers from the driver determine the volume of the box? Is there any other way to make the box smaller? Otherwise would the driver below be substantially smaller? Im looking for the box to be 5 cu ft max. Is that possible? Or am I better off just going with a vented enclosure...

Thanks for all the help so far! It's very much appreciated!


Model:06S8L72
Nominal Impedance(Ohms)2
SPL dB 1W/1M:83.4
Displacement, cc:980
Displacement, cu.in.:59.8
Hole cutout, in dia:7 5/8
Mounting Depth, in.:4 11/16
Revc:3.305
VC Inductance, mH:2.77
Sd, m3:0.0273
BL:14.29
Vas, Liters:10.075
Vas, CuFt:0.36
Moving Mass , oz.:4.83
Fs:44.1
Qms:7.064
Qes:0.614
Qts:0.5645
Peak Power Handling, watts:900
EXmax, mm:12.2

 

[GM]

Fs, Vas, Qts sets box size and for a TL its length is normally a function of Fs, so a low Fs combined with a high Vas and medium Qts = big box. Even tuning the 05C154 up around 60 Hz requires ~6.5 ft^3 and a T/S max flat vented alignment is 9+ ft^3, so no help there. A prosound vented alignment OTOH is only ~3.7 ft^3, though of course not much deep bass output either:

Vb = 3.684 ft^3 net
port = 5" dia. x 24"

BTW, what brand drivers are these?

GM

 

[GM]

Model:06S8L72

Are these specs for real?! With such a tiny Vas, these are best suited for a ~IB sealed cab, though an oversize, but still small, TL could be used.

GM

 

[h22lude]

These are all Kicker drivers. So the 06S8L72 wouldnt benefit from a TL? They do really well in vented enclosures. So I was really curious to see how they would sound in a TL. Thanks!!

 

[bjorno]

TL simulation with a smaller cabinet and a ported box to compare with.

B

1(4)

 

[bjorno]

2(4)

 

[bjorno]

3(4)

 

[bjorno]

4(4)

 

[h22lude]

Okay thanks for those sheets bjorno! you saved me alot of time!! I think im going to go ahead and try out the 06S8L72 in a TL box as long as i can get it under 5 ft^3.. Thanks again!

 

[GM]

These are all Kicker drivers. So the 06S8L72 wouldnt benefit from a TL?

You're welcome!

Ah! Car audio drivers. Not really. For instance, tuned to Fs the pipe isn't big enough to put the driver in it since its net Vb is only 0.83 ft^3 and why I noted a TL would need to be oversize, which will result in excessive stuffing due to being under-damped. So if you still want to try it, then make it ~75.5" long and just big enough to mount the driver.

WRT the other driver, if you use two in a clamshell isobaric, then a TL will be fairly compact, but best to find a driver that ~meets your needs. For instance, a driver with a 25 Hz Fs, 4 ft^3 Vas and 0.5 Qts will work well in 5 ft^3 net.

GM

 

[h22lude]

Thanks GM!! That helped alot i never fully understood what i was looking at when i looked at QTS and VAS. but now i definately have a better understanding of their relationship to the enclosure.

I think i'll give that TL a try if i have spare time at work. So 75.5 " long? does it matter how many turns i make throughout the line? and will not tapering it make it sound bad? Is the tapering evenly gradual all the way throughout?

How do i calculate what the total box volume should be??
Do TL's benefit from putting gussets in the corners?

 

[GM]

Thanks GM!!

does it matter how many turns i make throughout the line? and will not tapering it make it sound bad?

Is the tapering evenly gradual all the way throughout?

How do i calculate what the total box volume should be??

Do TL's benefit from putting gussets in the corners?

You're welcome!

Not really.

There's no taper, a TL is a constant taper (straight) pipe.

Figure the pipe's minimum internal width, depth based on the driver's dims and multiply them by 75.5" to get net Vb less driver.

Not for sonics, but they do brace the corner joints if you feel they need it due to using butt joints/whatever. Ideally you want to fill any cavities with a massive material such as sterile sand, kitty litter or similar.

GM