speakers box design

[tom_haric]

Hi everyone!

How would it be, if the box of a speaker was a sphere formed and made of masive wood (one piece).
What kind of quality of a sound would it gave?

Thank you!!!

Have a nice day.

[sgt bass08]

[QUOTE=tom_haric]Hi everyone!

How would it be, if the box of a speaker was a sphere formed and made of masive wood (one piece).
What kind of quality of a sound would it gave?

hi a speaker can be made in all different shapes.ive seen some crazy shape speakers made by kef .so it doesent really matter what shape you wont try it.wood is a huge part of constructing a speaker.what do you mean by massive wood (one piece)?.there only two options in wood hard wood and soft wood .there wouldnt really be any differents accpect soft wood absorbs more.hard wood will bounce a little more.but im not 100% sure they my be more to it .but thats my advice .

[kexodusc]

The shape of the cabinet definitely contributes to the sound -
Internal resonances would be minimized by a spherical shape, and cabinet diffraction artifacts outside would be less of an issue than most flat, box speakers. How big a difference would this make? Well, I think it is a secondary concern to the choice of drivers and crossover design, but you'd be able to hear some difference between a rectangular box and spherical box.

Also, you want a hard, non-porous material of consistent density. Unfortunately most wood types aren't non-porous and of consistent density (think knots, imperfections, etc), while preferable for furniture and aesthetics, don't make good cabinet materials despite the odd speaker manufacturer marketing-spin about using "real wood". The woods that do meet the criteria are usually very expensive, and many believe better sound is achieved by investing that money in better electronic components.

[basite]

yes, the shape definately does matter!

all what Kex said :)

don't forget the drivers too though, and the crossover...
these parts have to be high quality too, and most importantly, work well together. It's not just getting the best and throwing it into a box.

[johnny p]

How would it be, if the box of a speaker was a sphere formed and made of masive wood (one piece).
What kind of quality of a sound would it gave?

I'm under the impression that old speakers from Salvation Army that cost $5 would sound better than anything I could possibly make. That being said, you have intrigued me with you conceptual design of speakers..... so here's what I am picturing, and tell me how far off I am (I'll add a suggestion or two also, but keep in mind I know nothing about nothing)

Solid wood, being starting with a kiln-dried solid, one piece hardwood, something very nice asthetically, such as Lake Recovered Hemlock, etc.

Take that wood, hollow it out to the exact size to accept the woofer, etc, that you will place inside it.

Possibly burn the inside of the wood to make it more of a solid, pore-free surface (much like whiskey barrels?)

sand the outside to bring out the wood grain, etc. and get the desired shape, and possibly cover with a clear sealant.

Find a way to mount it or make the bottom flat to use as bookshelfs


All this being said, I think if done properly it could make for some very nice looking custom speakers that would basically be a work of art, and certainly a converstation piece. as far as sound quality, I think you're gonna go through a LOT of effort to make them look nice and when it's all said and done, they might sound terrible..... I'd just get mid-level cones, etc. and use them more for asthetic reasons.


Am I far off?

I think about the root-tables (the ones where the cut off the roots, and trunk of a tree and seal it and put a glass top on it for a table) or the ones people place on the wall with clocks in them, it's the same concept, it's using something found in nature, and adding the electronic guts to it.

[tom_haric]

http://img80.imageshack.us/my.php?image=zvoniki3po4.jpg

This is a link of a picture (i hope it works). I draw this in autocad....

Ok, if i got it right... If you made good adjusment, you can get a very good sound. Even in this kind of speakers..

Also... Dont take this so serious. It's just an idea of possible product that "my" machine could product.. My task is made a concept of a machine which could made something like that.. Diploma stuf.

I wish to excuse for possible bad English.. I'm from no speaking English area. :)

[sgt bass08]

The shape of the cabinet definitely contributes to the sound -
Internal resonances would be minimized by a spherical shape, and cabinet diffraction artifacts outside would be less of an issue than most flat, box speakers. How big a difference would this make? Well, I think it is a secondary concern to the choice of drivers and crossover design, but you'd be able to hear some difference between a rectangular box and spherical box.

Also, you want a hard, non-porous material of consistent density. Unfortunately most wood types aren't non-porous and of consistent density (think knots, imperfections, etc), while preferable for furniture and aesthetics, don't make good cabinet materials despite the odd speaker manufacturer marketing-spin about using "real wood". The woods that do meet the criteria are usually very expensive, and many believe better sound is achieved by investing that money in better electronic components.


i dont understand shape of the cabinet definitely contributes to sound.ive seen all different size shapes just look at the old kef speakers and tdl speakers or even bose .they can be anything you could have a triangle shape speaker and compare it to a rectangle speaker there would be no differents .the most important thing is the mass or the litre of space .as long as a speakers as got a nuff mass so that the sound waves can move .the more litre of space or more mass the better .so the shape of the speaker doesent matter .also why do you need expensive wood most speakers are made of mdf ???.the expensive part is going to be the high mid low drivers or electronic components .

[johnny p]

Ah... I see what you're looking at...... It could work (I'd redesign the stand part, but that's just me..... maybe just another round ball under the other three....)

[sgt bass08]

hey thats a wicked desgin .ive seen that do some where else but caint rember.i would keep the two round balls at the top .but at the bottom make a huge rectangle box for the low ends that would be awesome. i would love to make speakers do you make speakers as a business or is it a hobby.:cornut:

[kexodusc]

i dont understand shape of the cabinet definitely contributes to sound.ive seen all different size shapes just look at the old kef speakers and tdl speakers or even bose .they can be anything you could have a triangle shape speaker and compare it to a rectangle speaker there would be no differents .the most important thing is the mass or the litre of space .as long as a speakers as got a nuff mass so that the sound waves can move .the more litre of space or more mass the better .so the shape of the speaker doesent matter .also why do you need expensive wood most speakers are made of mdf ???.the expensive part is going to be the high mid low drivers or electronic components .
I'm afraid you're over simplifying.

The shape of the speaker will determine it's volume, and more importantly the length of the vertical, horizontal, and height axes. These measurments will have a big impact on the interior standing waves inside the cabinet. The woofer moves forward and produces sound. It also has a backward motion that directs sound inside the cabinet. Just like your room would have standing waves, modes, and nodes, a speaker cabinet is also vulnerable to this. If not carefully considered, the cabinet can color the sound sound in the bass/midrange. This partially why speakers have damping material inside them, but that alone isn't enough. Best practice is to have no 2 dimensions the same size, or in any multiple of any other dimension. There are proven "Golden Ratios" for speaker cabinet dimensions. We try and spread the resonances over the broadest range of frequencies possible, so that total response is reasonably flat.

Also, the front baffle size and shape is very important. Sound waves don't just move forward out of the woofer/tweeter, but they radiate outward at all angles. Some of those sound waves will bounce off the front baffle towards the listener. When the frequency decreases, the wavelength size of soundwaves increases. What happens is some of the sound bounces off the cabinet and is re-inforced (louder) some of it actually wraps around the speaker and isn't re-enforced. This has to be compensated for in the crossover design. Wider baffles in some aspects are better for bass reinforcement,but offer a different set of challenges. Additionally, the edges of the front baffle have to be taken into consideration - diffraction introduces small, but noticeable artifacts in the response, most noticeable in the upper midrange and highs...you'll get a jagged, harsh response on a flat baffle with 90 ° edges. Not unlistenable by any means, but not optimal. Same reason why flush mounting tweeters is preferrable. Most of your higher end speaker cabinets will have rounded-over or chamfered edges to alleviate this.

Cabinet shape is a fundamental aspect of speaker design, you can go ahead and throw any drivers in a box, but it won't sound optimal unless these concerns are addressed. As with anything, this added complexity increases cost. Mass production cuts corners quite often. The speaker won't necessarily sound bad - but it won't sound as good as it could.

[basite]

i dont understand shape of the cabinet definitely contributes to sound.ive seen all different size shapes just look at the old kef speakers and tdl speakers or even bose .they can be anything you could have a triangle shape speaker and compare it to a rectangle speaker there would be no differents .the most important thing is the mass or the litre of space .as long as a speakers as got a nuff mass so that the sound waves can move .the more litre of space or more mass the better .so the shape of the speaker doesent matter .also why do you need expensive wood most speakers are made of mdf ???.the expensive part is going to be the high mid low drivers or electronic components .


speaker drivers extrude, once you put power in them, they move forward. but after that, they move backwards again, even behind their original resting position. All of this creates soundwaves (the theory is a tad longer, but this is just 'in a nutshell'), but in the cabinet, there are also soundwaves :yikes:, where do they go? in a simple cubic box (or rectangular, for that matter) those waves will reflect too much in the cabinet (even with alot of damping materials inside them), and create standing waves (http://hyperphysics.phy-astr.gsu.edu/Hbase/waves/standw.html). which cause distortion and an unflat frequency response.

apart from that, using the wrong material, will change the resonance frequency, which will then also cause disortion, and limit the speaker's frequency response.

then, making the box too large or too small will change the frequency response, a too small box generally means little bass response and much disortion, a too big box will give a frequency boost somewhere around 60-150 hz, and not much bass below that.

a closed (sealed) enclosure puts out 'less' bass, but the bass will attenuate slower than in a ported enclosure (around 12db per octave in a sealed enclosure and around 15 (or 18) db in a ported one), a sealed enclosure also gives a tighter, more correct bass. A bad designed ported speaker gives sloppy, muddy bass without defenition.
then you also have passive radiators and stuff like that
and driver placement, and ways of mounting them (normal, isobarik, ...)
and that's for the inside only.
the outside is at least as complicated. DO mind that these are just BASIC things, no calculations or so, no details, and only a top of the iceberg.


anyways.Tom, that design looks very promising.

however, slight adjustments could still be made...

which drivers are you planning to use? and if you don't know, could you give the dimensions of the speaker (each ball) and maybe the sizes of driver you are going to use?

Check out B&W's website for alot of information, they use 'balls' too for their mids and tweeters (in the 800 serie and nautilus serie only...)

Keep them spinning,
Bert.

[sgt bass08]

i see but still as long as you get the measurment right .just getting the size cubic will be very important.aswell as depth of the speaker unit so the soundwave can move around.i like the idea of big depth in the low end frequency.as the bass then will sound better .its a shame we dont see many different shapes and desgin speaker.most manufactres tend to keep the standard tall rectangle shape.the only speakers i can rember that were shaped different from most speakers today.were some kefs and some tdl speakers wich they were tranigle shaped.

[kexodusc]

i see but still as long as you get the measurment right .just getting the size cubic will be very important.aswell as depth of the speaker unit so the soundwave can move around.i like the idea of big depth in the low end frequency.as the bass then will sound better .its a shame we dont see many different shapes and desgin speaker.most manufactres tend to keep the standard tall rectangle shape.the only speakers i can rember that were shaped different from most speakers today.were some kefs and some tdl speakers wich they were tranigle shaped.

The triangle or pyramid shape speakers are a bit tougher to build. It's not as sturdy and rigid as a plain rectangular box, and bracing can become a problem towards the top. But they look cool, IMO. Nice thing about that design, the width and depth axes are constantly reducing in size as you move from top to bottom - cuts down on some resonances. I think companies don't do it because it increases the cost a bit and with so many speakers out there now, pricing is very important.

Axiom has a neat approach to speakers...the front is wider than the back - that angle helps cut down on resonaces as well.

There's plenty of different shapes and sizes out there if you look for them, what a lot of designers do is use compartments, or boxes inside boxes to cheat. That allows them to throw together some nifty looking designs.

[basite]

i can rember that were shaped different from most speakers today.were some kefs and some tdl speakers wich they were tranigle shaped.


see:

B&W (everything from the 700 serie and up)
Kef
Monitor audio's platinum serie
Avalon
Thiel
Wharfedale
JM labs
Wilson audio
Avantgarde
Floating (especially their Synthese)
Verity audio
Audio Physic
probably every planar speaker
the higher Dynaudio lines
some Dali speakers too I think
Hansen Audio
and alot of others, but these are the first that came to mind...

Keep them spinning,
Bert.

[GMichael]

I would think that a speaker that is perfectly spherical might have standing wave issues similar to that of a box with all sides being equal. Maybe an elliptical enclosure would be better.
But as Kex said, the components and baffles you use will make a bigger difference.

[kexodusc]

I would think that a speaker that is perfectly spherical might have standing wave issues similar to that of a box with all sides being equal. Maybe an elliptical enclosure would be better.
But as Kex said, the components and baffles you use will make a bigger difference.
The sphere still has the resonance issues and standing waves like any 3 dimensional cabinet will but, the distribution of the frequencies is more broad instead of concentrated at a constant frequency....not sure I explained that well, but hopefully you get what I mean.
Think of a rectangle - start on the front wall. Everywhere along that front wall is the same distance from the parallel point on the opposite wall. In a sphere that doesn't happen. Draw a line through the middle of the circle. It's length will be X. Now draw another line, parallel to the side of it...that length will be shorter...the length continues to decrease...this effect, sort of distributes the negative effects more broadly than in a rectangle...
Err...I think...:confused5:

[johnny p]

here's a spherical sub design......

http://www.hometheaterstore.com/B_W_PV1_SubWoofer_2_8_Powered_500_WATT_p/pv1.htm

[basite]

if you really want to get the most out of your project, you should take this thread to www.Audiokarma.org , there are quite alot of DIY dudes there, most of them very familiar with speaker box calculations and stuff, there might be useful tips there too...

(I'm a member there too, you'll find me in the Mcintosh room :))

Keep them spinning,
Bert.

[GMichael]

The sphere still has the resonance issues and standing waves like any 3 dimensional cabinet will but, the distribution of the frequencies is more broad instead of concentrated at a constant frequency....not sure I explained that well, but hopefully you get what I mean.
Think of a rectangle - start on the front wall. Everywhere along that front wall is the same distance from the parallel point on the opposite wall. In a sphere that doesn't happen. Draw a line through the middle of the circle. It's length will be X. Now draw another line, parallel to the side of it...that length will be shorter...the length continues to decrease...this effect, sort of distributes the negative effects more broadly than in a rectangle...
Err...I think...:confused5:

I see what you mean. I'm not sure if this does the same thing but, draw an X in the middle of a circle. Both lines are the same length.
Years ago as a kid we had a round pool. If you jumped up and down in the center (holding some kind of floating device) you would get what looked like standing waves. Wouldn't the same thing happen in a sphere?
Not that I know. Just theorizing.

[sgt bass08]

The sphere still has the resonance issues and standing waves like any 3 dimensional cabinet will but, the distribution of the frequencies is more broad instead of concentrated at a constant frequency....not sure I explained that well, but hopefully you get what I mean.
Think of a rectangle - start on the front wall. Everywhere along that front wall is the same distance from the parallel point on the opposite wall. In a sphere that doesn't happen. Draw a line through the middle of the circle. It's length will be X. Now draw another line, parallel to the side of it...that length will be shorter...the length continues to decrease...this effect, sort of distributes the negative effects more broadly than in a rectangle...
Err...I think...:confused5:

kex i like that idea .because with rectangle and square speakers you are get even width so the measurement are even wich will help to stable the soundwaves .so the resonance will maximum to its full .the rectangle will keep the resonance even all threw the cabinet.wich will keep the sound natural and equal.its a bit like building a house on 4 side its going to be stable not just on the structure but on the resonance.but would you really wont a different shape speaker in your room .ive seen some that tilt and some like pyramind and they do look ugly.they dont look like speakers more like some scary furniture.but the sphere speakesr look cailm and relaxing i like sphere speakers they should make more.but how would resonance work with sphere shape speaker.but arent sphere shapes even as the sound resonance is still traveling without changing because its in a sphere there no decreasing in size just bending the waves equal around the mass of the sphere.