New Vented/Closed Spreadsheet

[gregorx]

Hi All,
I just created a new spreadsheet for traditional loudspeaker design.

Loudspeaker Spreadsheet (no macros)

When I am trying to learn something I find that it helps to design software or, in this case worksheets, to understand as much as I can about the subject. I searched the web and books to gather most of the formulae but the dimensions are my own.

This spreadsheet calculates HxWxD dimensions using Phi and provides several different vented box solutions and port lengths as well as custom volume solutions. You can also plot the various solutions' frequency response.

If you have the time I would love to hear from fellow DIYers about the spreadsheet and any and all comments or suggestions would be well appreciated.

If you are new to this, like me, I hope you find the spreadsheet useful.

Thanks,
Gregory

 

[rwagter]

Gregory,

very nice and simple to use spreadsheet. I only have 1 question: the ventdiameter doesn't change if I select more then 1 vent?

Ralph

 

[gregorx]

Vent Diameter

Hi Ralph,
Thanks for you kind words.

The vent length changes but the diameter does not. Should it?

My impression was that the reason to add more than 1 port/vent is to increase the port area to reduce turbulance at the openings and thus you would usually keep the same diameter.

Gregory

 

[Ron E]

Nice beginner level sheet. a few comments:

The proper formula for sound speed is 20.06*sqrt(T+273)

Your X's for plotting are locked.

It would be more readable if you removed some of the unnecessary precision in the calculations. I doubt anyone needs to see precision past the 2nd decimal place for most calcs.

 

[gregorx]

Nice beginner level sheet. a few comments:

The proper formula for sound speed is 20.06*sqrt(T+273)

Thanks. I used the less than proper speed
from the url below and the proper formula was starring me in the face.
http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe3.html#c1

Your X's for plotting are locked.

I have fixed these, thanks again, and also fixed the speed to proper.

It would be more readable if you removed some of the unnecessary precision in the calculations. I doubt anyone needs to see precision past the 2nd decimal place for most calcs.

I made them 4 and it does look less intimidating.

Thanks again Ron, great comments!

 

[gregorx]

Peak Velocity at the port

Does anyone know how to calculate the peak velocity at the port to make sure it is below 18 m/s or so.

 

[rwagter]

I don't have the formula for peak velocity only for the minimum diameter:

39.97.((411.25.Vd)/Fb^0.5)^0.5

folowing the optimum lenght:

((1.463.10^7.R^2)/(fb^2.Vb))-1.463.R

Vb is in cm^3

Perhaps you should contact kristian ougaard, he design unibox and has a airspeed graph inserted.

Ralph