Ratios for internal dimensions of speaker box

[bm_mode]

The book I'm using gives me the "golden ratio" and an accoustic ratio for the dimensions of a rectangular speaker box, but neither of these will give me what I am wanting (aesthetically). Does anyone know some ratios that will give the (currently fashionable) tall thin floor-standing speakers?

Could someone also explain how the ratios used for box dimensions are derived? I realise it's something to do with minimising standing waves, but what criteria must the ratios meet to minimise standing waves?

Thanks for your help.
Joseph.

 

[BAM]

The best way to reduce standing waves is to make sure that the back wave off the driver does not reflect in the same two places. The Golden Ratio offers a very narrow side profile, which can be made into the front. However, you will wind up with an enclosure with a long depth.

 

[walker]

Bm_mode the golden ratios make it easier to steer clear of harmonics problems within a speaker enclosure.
This is more important for ported boxes or enclosures that have minimal filling. If your design is sealed and fibre filled you will have less problems. If your design is ported then select the internal dimensions so that their resonances don’t occur at the driver, frequency response, high points. If it is possible you may be able to assist low points in the response.
Dimension (ft)=1130/frequency (Hz)

If you don't want to go to that trouble just make sure that the three major dimensions are different.

You could make your enclosure without parallel sides, this has been done effectively many times before.
Regards WALKER

 

[tomcat]

From what I have read on the subject in various mags/journals over the years, the main criteria is to avoid even multiples of the dimension of another side. In other words keep the dimensions to odd multiples and this will prevent sympathetic resonances/harmonics build up. I hope you get the idea... but this is the simplest way I can explain it.
tomcat

 

[jimstewart]

I know this is really old.

I know this is a really old post but I found it fast on the net so I will offer what I have found to others that might find this as I did.

golden ratios
1 : 1.14 : 1.39
1 : 1.26 : 1.59
1 : 1.28 : 1.54
1 : 1.44 : 2
1 : 1.60 : 2.33
1 : 1.62 : 2.63

I am currently looking for a ratio that will also allow me to make a very tall narrow enclosure. Except ulike these ratios I don't want it too deep. If I am successful in my endeavorer I will return and update this list further.

 

[sreten]

Re: I know this is really old.

I am currently looking for a ratio that will also allow me to make a very tall narrow enclosure. Except ulike these ratios I don't want it too deep. If I am successful in my endeavorer I will return and update this list further.

Hi,

Make them any different width and depth you like, simply avoid
1:1.5 or 2.0. Make them any height you like but avoid x2 or x3
of the width or depth. Avoid symmetrical / equal area bracing.

/sreten.

 

[augerpro]

Try using Boxnotes

Try to keep the resonances from piling up one each other, being multiples of others, or in sensitive frequency ranges. Pretty handy little program.