Speaker box design vs dimensions

Bubinga99

Looking for advice if anyone here knows much about how changes in box geometry or volume affect the response.

Reason I ask, I'm thinking of building something like these Dennis Murphy CAWO1 (still looking at others though) at http://murphyblaster.com/content.php?f=CAOW1.html,
and he gives the crossover design and box dimensions, but also says a box 4" taller (allows more room to fit the crossover) is OK.

I'm thinking of modifying the box plans a bit, with sloped/curved sides.

Do the height-width-length dimension matter individually, or is it just the total volume that matters? That increase of 4" in height increases the volume by 36%, so is it correct to say you can increase the volume of a baseline design by that much in general, and not have it affect the response?

Systems

The width of the baffle is important as the crossover was likely optimized with that width.Changing it more than an inch or so will affect the response in the lower midrange/ upper bass.

Increasing the volume by 36% will change the bass response(,ie lowering it) and in the case of a sealed box lowering the system Q.Changing the volume of a ported box will require the retuning of the ports.

kcoc321

regarding the 4" increase it says in the description that it is a separate compartment at the bottom to house the crossover. so it would not add to the cabinet volume.
He also says "This approach is highly recommended in any event, since it's very difficult to squeeze all of those parts into the main interior space of the cabinet."

Systems

kcoc321 wrote: »

regarding the 4" increase it says in the description that it is a separate compartment at the bottom to house the crossover. so it would not add to the cabinet volume.
He also says "This approach is highly recommended in any event, since it's very difficult to squeeze all of those parts into the main interior space of the cabinet."

Then no changes in response should occur If you are only adding 4" to the height and not changing internal volume.

Bubinga99

kcoc321 wrote: »

regarding the 4" increase it says in the description that it is a separate compartment at the bottom to house the crossover. so it would not add to the cabinet volume.

Ah, OK. I didn't read that quite as literally first time through, and just thought he was saying there was now more room for the crossover. But after re-reading it (and knowing now that a cabinet volume change would require re-tuning the port), you must be right. The 4" larger cabinet must have sort of a double bottom and a physically isolated compartment.

So it sounds like my plans for say angled/curved sides (even if I add to the cabinet depth so the designed volume stays the same) will change the response in unknown ways since it changes the front baffle geometry (could be improved; could be worse; but definitely not the same). Bummer.

Thanks for the info, even though discouraging. I'm just not all that interested in building a utilitarian rectangular box. Guess I have to figure out what it takes/costs to get set up to do my own measurements on box variations. Any advice on that (software/hardware-wise)?

Systems

Here is a good desription of how baffle size/shape affect response.http://www.trueaudio.com/st_diff1.htm and a free program to simulate it.http://www.tolvan.com/edge/help.htm
searching the term "baffle step compensation " should yield lots of good reading.

If your plan is just to round over the edges,that will actually improve response some.

kcoc321

I wouldn't get too discouraged. There are tons of curved sided mini speakers designs around.
Heck,I would be willing to bet the designer you are looking at is probably working on one right now, as I doubt you are the first one asking for it.
Have you emailed him and asked if he has a curved sided design for the same components?

As far as software goes, WinSpeakerz seems to be a popular program.

Bubinga99

Excellent info and ideas; thanks guys.