My DIY speakers "J&N"

[jororaitchev]

I understand Archimedes Principle, but it involves comparing weight in water with "free weight" to calculate density.

What I don't follow is how you are establishing the weight in water!
Archimedes requires determining the force of buoyancy and I do not follow how you determine it.
Or what clever trick you use to avoid it.

Archimedes used the floating force to find out if there is silver in the royal crown.

I tried to explain to you that the specific resistance of MDF in my measurements is taken in pure weight units and removed from the total weight of the water in the cabinet volume.
Joro

 

[jororaitchev]

And continue with my "clever trick";
Let's assume that the density of MDF is 0.75 kg. of cubic decimeter/ average value by tables /. This is 75% of the actual reduced volume.
The reduced volume error is:
3.5 / 0.75 = 4.6 liters actual reduced volume, and the whole volume is 43-4.6 = 38.4 liters.
The total error of 39.6 liters is 1.2 liters or -3.1%.

 

[MrBoat]

I understand what you are saying, jororaitchev. Initially, I was more concerned with the volume before the enclosures were built during the design and drafting phase. It never occurred to me one would measure after with something like a speaker cabinet. I have seen Archimedes principle applied for displacement, or the volume of solid, irregular shaped objects. I have used Archimedes principle to measure lard for baking to keep from having to pack a measuring cup with the fat.

In the case of ship building, these volumes are known for the most part, with an adjustment feature built in by way of added or removed ballast perhaps, provided they are relatively close to start with. A ship hull comes from the architect with a designed waterline before the first piece of material is cut. When the boat is launched, it will be stated that she "rests on her lines". . . .hopefully.

 

[MrBoat]

Of course! ... as long as you are measuring the amount displaced with beans. Duh! I was thinking about the missed volume of the gaps between beans, but that doesn't matter as long as it is consistent.
I must say however that for a complex shape with many pockets like Jororaitchev's frame, I'd want to employ a shaker or tumbler to make sure all of the voids get filled!

Dry beans are very settling due to their irregular, smooth shape, their weight and their slippery and hard exterior. You could essentially stir them into place. They also come in a variety of sizes to match scale.

Ok, I am not totally serious but, it would work in a pinch if one did not want to source or construct something more complicated. I grew up knowing some pretty resourceful thinkers that could make due with whatever was around them with some surprisingly accurate results. Those left/right brain types.

Dry sand can even be used to measure volume, as it is fluid enough to find it's way through the hourglass.

 

[jororaitchev]

I can now start collecting the cabinet;

 

[jororaitchev]

I have an idea to make a new project to in the base there should be two 10" loudspeakers - just an idea. They look like animals, maybe dinosaurs, but important are 20Hz.

 

[KEW]

I have an idea to make a new project to in the base there should be two 10" loudspeakers - just an idea. They look like animals, maybe dinosaurs, but important are 20Hz.View attachment 21789 View attachment 21790

You need to raise your ceiling, scale up this model so they tower over you and build the speakers into the abdomen and chest cavities!

 

[jororaitchev]

You need to raise your ceiling, scale up this model so they tower over you and build the speakers into the abdomen and chest cavities!

My high ceiling criteria differ from reality,this "Lego" is very good!

 

[jororaitchev]

And the original model will look like this;

 

[jororaitchev]

I continue with the collection of the cabinet;

Now I can make the exact measurement of the volume. And that's 31.5l, just as much as I need!
Oh, l forget to show you what I did to get that volume!
I maked a filter compartment (for the MW and TW), the W section will be in the box;

I previously make the last layer-10 mm MDF / to get a sandwich construction / on the front panel and the bottom;

Last constructive action ;
After 10 hours I will install the last layers of 2 x 4 mm bent MDF;

 

[jororaitchev]

A small structural change for the side panels, last layer is 1 x 4 mm plywood and everything is re ady for the measurements.

 

[KEW]

It a delight just to look at your constructions!
Woodworking porn FTW!

 

[jororaitchev]

It a delight just to look at your constructions!

Thanks!
And a risky picture (everything is supported by gravity), how look for compared to the frontal columns, are not on one line, but I rely on your imagination.

 

[jororaitchev]

Several steps to the moment with measurements ...

 

[KEW]

Several steps to the moment with measurements ...
View attachment 22260 View attachment 22261 View attachment 22262 View attachment 22263

For some reason, that white reminds me of the helmets from "2001: A Space Oddyssey"! Beautiful!
What are your finish plans for the bases?

 

[jororaitchev]

If we have to associate with the white, it is with the helmets of the warriors of "Star Wars".
This is the project of the rear speakers, will finish it with "Bird's eye view".

 

[jororaitchev]

The first home tests are good.
My current surround speakers of " Technics" CA-10 with a good sound from 1997, they are sadly retreated himself ...

 

[ARES24]

I don't think I have seen a single project with this much effort in it! Very nice work.


Apparently you are not building these for someone else and charging them by the hour

 

[jororaitchev]

I don't think I have seen a single project with this much effort in it! Very nice work.


Apparently you are not building these for someone else and charging them by the hour

Thank you for your good evaluation of my work!
These speakers was sold to a client builds his house at that moment , the time for the project to run is about 3 years.

 

[jororaitchev]

After the measurements, this is are Technical data:
Frequence Range; 33-25000 Hz
Long term Max Power; 200 W
Crossover Frequency; 2800 Hz
Impedance; 4 Ohms
Sensitivity; 90 db SPL
Cabinet Volume; 31 L
Gross weight / without stand /; 27kg.

There will be a sequel ...sometime..

Joro Raitchev
Sofia- Bulgaria