Hi
I am about to build a bass reflex speaker with 15inch driver. I have the ideal dimensions for the cabinet and port which are close to meeting the golden rule for dimensions.
However to keep the wife happy I am forced to change the shape, whilst keeping the internal volume the same.
Unfortunately now I could end up with a cabinet which seems to fulfil the worst dimensions - typically 800x800x400cm (two dimensions the same and one is half of that value).
What would I get in terms of frequency aberations if I built this box. The sub will only be required to cross over at about 75Hz.
Can internal damping help?
Cheers Winnie
I am about to build a bass reflex speaker with 15inch driver. I have the ideal dimensions for the cabinet and port which are close to meeting the golden rule for dimensions.
However to keep the wife happy I am forced to change the shape, whilst keeping the internal volume the same.
Unfortunately now I could end up with a cabinet which seems to fulfil the worst dimensions - typically 800x800x400cm (two dimensions the same and one is half of that value).
What would I get in terms of frequency aberations if I built this box. The sub will only be required to cross over at about 75Hz.
Can internal damping help?
Cheers Winnie
If you're using it as a sub, the dimensions won't give you any problems; to get standing waves, the waves need standing room, and your box is way tiny compared to the shortest wave you're talking about. 1kHz is one foot, 100 Hz is ten feet, so your box (with a maximum dimenion of less than three feet) won't be used anywhere near a regime where any golden ratio or similar scheme is significant.
At the frequencies you're designing it for, I don't think the shape of the enclosure will make a difference. For higher frequencies, standing waves are an issue, and hence the enclosure shape is important. Low frequency wavelengths are much longer and internal standing waves are not an issue in the same way.
Someone will confirm this hopefully.
Someone will confirm this hopefully.
I'm faster on the keyboard!😉 But it's always reassuring when someone gets the same answer independently from two sources.
One important qualification that's not relevant in this particular case: if you make an enclosure too long and narrow, you can get some funny pipe effects.
One important qualification that's not relevant in this particular case: if you make an enclosure too long and narrow, you can get some funny pipe effects.
Mrs. Y assures me that there's a difference between 25 mm and 25 cm. I assumed/hope that winnie actually meant the former.
Thanks guys
That's very reassuring. You did of course spot the deliberate mistake - dimensions are in mm not cm.
That's very reassuring. You did of course spot the deliberate mistake - dimensions are in mm not cm.
Dont mind standing waves, better think about bracing your box, that way the box wont "ring" (Place your ear on the sp. cabinet and you'll hear it)
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