R

Randall Flagg

Audiophyte
Hello, new here!

Looking to build a cheap sub so I ordered a Lase 21LW-2400....yikes. I may have made a mistake.
No Vas available, even after emailing Lase.

Thiele & Small Parameters
  • Resonance Frequency : 37Hz.
  • DC Resistance : 6.5 ohm
  • Mechanical Factor : Qms 5.754
  • Electrical Factor :Qes 0.768
  • Total Factor: Qts 0.391
  • BL Factor : BL 27.2T. M
  • Effective Moving Mass : 245.317gr
  • Compliance : 123.14M/N
Is this a lost cause? All the box programs demand Vas.

Thanks....
 
ryanosaur

ryanosaur

Audioholic Overlord
They give a formula here for solving for Vas:


On another point, what is your goal with this subwoofer... that Fs is awfully high. Looks maybe like a pro-audio driver, perhaps.

How are you going to be using it?
 
William Lemmerhirt

William Lemmerhirt

Audioholic Overlord
They give a formula here for solving for Vas:


On another point, what is your goal with this subwoofer... that Fs is awfully high. Looks maybe like a pro-audio driver, perhaps.

How are you going to be using it?
Yes. That FS is a big one for me too.
 
ryanosaur

ryanosaur

Audioholic Overlord
Yes. That FS is a big one for me too.
For the cost of that driver, you could build a Dayton Kit pretty much, and by most accounts get better performance down low.
Or, there's this 18" driver:

Or 2 of these for duals!

A lot of options that can get you there! ;)
 
R

Randall Flagg

Audiophyte
Thanks for your replies...
Sadly, the Pyle 21 was not available at a reasonable price when I was drinking and chose a driver before first investigating it lol.
My intention was another low cost 4th order driven by a class D.
It never occured to me I'd end up getting a driver without specs.
"Vas = (rho*c^2*Sd^2)/(4*pi^2*Fs^2*Mms)"
I can't use that formula. What is rho!?, what is c? Is this metric or what?
I had found that thread a couple weeks ago and seems it's irrelevant to reality.
Maybe I should just return this thing and track down a Pyle. The 4th order box I had built lit up at 20 and knocked things off walls.
 
Verdinut

Verdinut

Audioholic Spartan
Hello, new here!

Looking to build a cheap sub so I ordered a Lase 21LW-2400....yikes. I may have made a mistake.
No Vas available, even after emailing Lase.

Thiele & Small Parameters
  • Resonance Frequency : 37Hz.
  • DC Resistance : 6.5 ohm
  • Mechanical Factor : Qms 5.754
  • Electrical Factor :Qes 0.768
  • Total Factor: Qts 0.391
  • BL Factor : BL 27.2T. M
  • Effective Moving Mass : 245.317gr
  • Compliance : 123.14M/N
Is this a lost cause? All the box programs demand Vas.

Thanks....
You can get one of the DATS speaker testing kits from Parts-Express which will measure the VAS and enable you to compare with the values which were provided by the manufacturer. Some speaker specs can vary by as much as 10% and even more.
Parts-Express have two testing kits and both of them are reliable. I have the more expensive one which I have used so often to measure Thiele/Small parameters, when building enclosures.

 

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