Miracles in Audio, by luck, by good choices,by design or by tweaking...

Thank you for the guidance and encouragement, mahgister! 
I will next start with Helmholtz resonators. The golden plates are on the way, and I habe one SG so far. 
I think the swing base is around 1200 Euro.

A SIMPLE EXPERIMENT DESIGNED TO AWAKE ACOUSTIC CONSCIOUSNESS



This experiment will not necessarily increase the quality of your audio experience or decrease it....The positive or negative impact is imprevisible for me because it is relative to your particular gear interaction with your room/ears....

This experiment will be audible with NO work to implement it...This is the reason why i propose it, there is NOTHING to do....

This is very simple and only suggested to you to make you listen what is the power of a single object can have on sound quality in a small room...

Take a big cylinder of any materials, 3 inches diameter and at least 2 feet high.... Put it at the reflection point to your right or left near the wall and listen...

This is only a primitive Helmholtz resonator without a neck....

This will give you an "idea" of how powerful and precise a mechanical equalizer could be when it is fine tuned...

Report the result....

And remark that all my results are gained with no money investment or very low one...

My goal is : audiophile experience at no cost with basic common sense and listenings experiments....

It seems that to place a tube of any kind and any lenght in a room to try a simple experiment in acoustic, the simplest possible experiment is too hard for most !

Or nobody read this thread....

The second alternative is probable....


😊

You all may benefit from placing a small 4 inch pie / tart tin pan below your SGs.YMMV, but I'm getting more mpg, and needing it. Gas prices are going up!

AN IMPORTANT FACT ABOUT HELMHOLTZ RESONATORS USED AS DIFFUSERS






The underestimated fact of their powerful capacity as sound diffusion engine...

I used them like resonators to damp and enhance some frequencies.... With mechanically tunable straws of different diameter and lenghts as necks...

But i used them also not only as tubes and pipes resonators but as DIFFUSERs with 2 big empty glass water bottles of 50 liters with larger hole for the neck ( few inches) and this hole topped with 2 or 3 cardboard large tubes neck covered with thin fabric clothes and with some plastic surfaces punched with many small holes over it ....


The result is stupendous in my 2 listening position... They are very powerful diffusers.... And diffusion is very important to control in the right balance with absorbtion and reflection....

Cost: peanuts....





Here are some of the acoustical science facts i used:

«Change the volume of the air cavity, or the length or diameter of the neck, and the frequency of
resonance changes. The width of this absorption band depends on the friction of the system. A glass
bottle offers little friction to the vibrating air and would have a very narrow absorption band. Adding
a bit of gauze across the mouth of the bottle or stuffing a wisp of cotton into the neck, the amplitude of
vibration is reduced and the width of the absorption band is increased. For maximum effectiveness,
Helmholtz absorbers should be placed in areas of high modal sound pressure for the tuned frequency...


The sound impinging on a Helmholtz resonator that is not absorbed is reradiated. As the sound is
reradiated from the resonator opening, it tends to be radiated in a hemisphere. This means that unabsorbed energy is diffused, and diffusion of sound is very desirable in a studio or listening room...»

P.214 Master handbook of acoustics by Everest, Frederick Alton Pohlmann, Ken C.