Hey guys, I once built a TQWT but with 50's drivers based on drawings based on a slightly comparable driver, the results were not amazing. I now found a couple of Visaton FRS-8's in one of my crates and would like to make another effort building a fun set of speakers. They are meant to be on my desk, next to my screen. I will probably supplement the real low with a subwoofer that I still have lying around.
I would like to use PVC as it is easy to come by and easy to use. However, I have got no clue how to calculate the length of the pipe. Can anyone help me out?
I would like to use PVC as it is easy to come by and easy to use. However, I have got no clue how to calculate the length of the pipe. Can anyone help me out?
So basically you wan't a specific volume, and need to figure out the pipe measurements? There are equations for it, but fastest is one of the many online calculators, like this one: Volume of a Cylinder Calculator - Omni
Well, I need to figure out what the pipe measurements are, but I don't know what volume I should have yet. Or what the length of the pipe should be if looking at a TL setup to maximize bass for instance.
I did find the driver in the Loudspeaker database
I did find the driver in the Loudspeaker database
With a simple TL, can't go wrong with an IB's 10x Vas with a < 2.0 Qts', just might be bigger than necessary. Pipe tuning cut length ROT = ~0.707x [Fs/Qts']. Damp to 'taste'.
Qts' = Qts + any added series resistance [Rs]: HiFi Loudspeaker Design
GM
Qts' = Qts + any added series resistance [Rs]: HiFi Loudspeaker Design
GM
Here's a 'no math' suggestion:
Parts Express suggest a suitable sealed volume of 0.06ft^3 (1.7 litres) for the FRS-8.
Obviously, the pipe diameter will have to exceed the driver's overall diameter of 3.07".
Once you've selected the pipe diameter, you can calculate the length required to suit the volume of 1.7 litres.
Start with a longer experimental pipe then shorten it in stages in order to find the optimum length sound-wise.
Stuff the finished pipes with absorbent to kill internal air resonances.
Parts Express suggest a suitable sealed volume of 0.06ft^3 (1.7 litres) for the FRS-8.
Obviously, the pipe diameter will have to exceed the driver's overall diameter of 3.07".
Once you've selected the pipe diameter, you can calculate the length required to suit the volume of 1.7 litres.
Start with a longer experimental pipe then shorten it in stages in order to find the optimum length sound-wise.
Stuff the finished pipes with absorbent to kill internal air resonances.
Correction, according to the technical drawing, the overall width is 93mm (3.7"). https://www.parts-express.com/pedocs/tech-diagrams/292-524-visaton-2004-technical-diagram.pdf
Duh ................
That's OK .... I have developed a new (armchair) system for optimizing T.L. s .
Since the driver Fo goes down as the pipe is lengthened ( by the added mass of the column)
AND
The 1/4 wave Fp also goes down ..... My calculator finds the point where the
2 frequencies converge : ) ....... In this case the Visiton FR8-8 needs to be on a 2"
pipe 41" long for Fsys of 82 Hz ....
That's OK .... I have developed a new (armchair) system for optimizing T.L. s .
Since the driver Fo goes down as the pipe is lengthened ( by the added mass of the column)
AND
The 1/4 wave Fp also goes down ..... My calculator finds the point where the
2 frequencies converge : ) ....... In this case the Visiton FR8-8 needs to be on a 2"
pipe 41" long for Fsys of 82 Hz ....
So, some kind of adapter and then glue that to a 2" diameter pipe that gives it a length completed of 41" and then stuff that thing. Completely open ended, or closed, or perhaps some kind of slot?
Ok, so when I would use a 4" pipe instead of a 2" pipe, I could almost half the length? And then do a 1" by 4" port at the end? Because I cannot make a 1"x4" port at the end of a 2" pipe.
Right ..... I ' m not sure of my calculator with the adaptor .
4" abs with caps ( home depot )
if you drill a 1" hole in a cap .....
one of these :
https://www.amazon.com/10-Pack-Cut-...=2025&creative=165953&creativeASIN=B00LORILBS
will screw in ( some effort and oil needed )
since they are 3/4 " they can be ~ 1" long
Do you have the 4 or 8 Ohm model ?
4" abs with caps ( home depot )
if you drill a 1" hole in a cap .....
one of these :
https://www.amazon.com/10-Pack-Cut-...=2025&creative=165953&creativeASIN=B00LORILBS
will screw in ( some effort and oil needed
)since they are 3/4 " they can be ~ 1" long
Do you have the 4 or 8 Ohm model ?
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