First this room "from Hell" is my laboratory, or dedicated room not a living room...
Then keep any sarcasm for yourself, people use them when they have no arguments and you seem articulate... 😁😊The photos in my virtual page has nothing to do with my actual room the images were taken before i iuse the Helmholtz method...
"Helmholtz treatment "only" work on ONE frequency and to bring down a peak in that very specific frequency and nothing more or less. Change the volume of the air cavity, or the length or diameter of the neck, and you change the frequency of resonance."
First Mechanical resonators are not DSP at all...Your comparison with DSP is flawed...
Why?
Because Helmholtz resonators (H.R.) absorb a larger bandwith and not a singular frequency...
And they DIFFUSE also other frequencies which are not absorbed...And they work in relation with the room geometry and size, and their placement is critical...Mine are mostly tubes with neck of various dimensions , some fabric cloth act as an absorbing material at the base of the tube end... They are made of different materials...
«Such a Helmholtz resonator has some very
interesting characteristics. For instance, sound is absorbed at the frequency of resonance and at nearby frequencies. The width of this absorption band depends on the friction of the system. A glass jug
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 jug or
stuffing a wisp of cotton into the neck, the amplitude of vibration is
reduced and the width of the absorption band is increased.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 a very desirable thing in a
studio or listening room.»
The Master Handbook of Acoustics Fourth Edition by F. Alton Everest P.215
Also all my H.R. are of different size, not one is the same in neck, lenght, volume or perimeter....For exemple one is 8 feet in my 8feet high1/2 inches in my studio, they ALL Differ by some ratio...
Then your comparison with DSP correction which use a one test frequency is flawed.,..A DSP dont absorb some bandwidth and dont diffuse some otrher bandwidth in some ratio at the same time...A DSP enhance some PRECISE test singular frequency...
Also i had a set of specialized Helmholtz diffusers or H.D. , which are way less known devices, this H.D. are OPEN TUBES OR PIPES, all of different lenghts and perimeter , then differering in volume, with a FILTERING GAZE or cloth fabric of different densities then of different absorptions properties... One mouth is open the other FILTERED by this gaze of various fabric densities or by a set a set of various thinner STRAWS of different size.... This created a powerful diffusion in critical placement....In particular near listening position and on the speaker themselves at precise location DIFFERENT for each one speaker by the way... Guess why? 😁😊
Location is KEY.... Like i said in my previous post i use the Haas law of the first wavefronts to tune my sound for EACH ear from EACH speaker.... My speaker are modified by H.D. placement around them or on them in an asymmetrical way to increase some acoustic crossfeed of large bandwidth...I even use a double two section foldable screen behind me to increase the acoustic crossfeed by the speaker A on the phantom image of B and speaker A on the phantom image of A for each one of my ears...
All the tuning was made on few months period daily, it was fun and very enlightening ...The work was exactly like a piano tuning but here it is a MUTUAL speakers/room tuning.... The H.D. and H.R. devices circle the room from the "HEAD" speker to the "TAIL" speaker with the "BELLY" of this acoustical SERPENT being my listening location chair with the FOCUSING lenses of the reflected waves of this foldable screen behind my head...
Time and timing of reflected and direct waves are the KEY...Reverberation control is key...
«A sound field in a room is composed of direct sound and reverberation. The interaural correlation follows the sinc function corresponding to the subjective diffuseness
in a room, as the distance increases from the source, when the sound source radiates random noise. However, for speech signals a listener is able to localize the
sound source even in the reverberant space. Early reflections within around 30 (ms)
of the direct sound enhance the energy of the direct sound. This positive enhancement due to early reflections can be explained by the Haas effect or the precedence
effect [18][44][45][46] in terms of the binaural sound localization.» Acoustic Signals and hearing Mikio Tohyama P.202
All my 8 headphones are in a closet now... Why ?
Because my room/speakers give me an intimacy, a dynamic, a soundscape, an imaging SUPERIOR to each one of them... I cannot go back to headphones...
When you correct the room with electronical tool unlike my mechanical devices which are part of the room, you cannot tune the room for TWO Listening locations like mechanical room tuning, and the tuning location with a microphone feed back and test frequency are valuable ONLY for a "sweet spot" which measure around one millimeter you bend the head and all ,easures are amok... In my room the sweespot are larger in nearfield listening (three feet) or my regular position (8 feet).... The regular position is more like regular speaker listening, the nearfield is nore headphone like , BUT in the two positions, acording to the recording album, the soundscape CIRCLE me almost and the listener is not in front of the music sometimes, but in the center with instruments sometimes around me...it is relative to EACH RECORDING effect... I can hears the acoustic bubble specific to each recording choices by the studio engineer...
Then before moching the lack of esthtic of my room, and his alleged efficiency think TWICE....
"Just imagine to take 100 books and place them on the floor, and scattered around on the floor around the sweet spot, and a book is far smaller than a Helmholtz resonator.. i can not imagine that mess.."
Your description has nothing to do with my H. grid location RESONATORS AND DIFFUSERS size and precise working location function for psycho-acoustic effect and not only physical acoustic effect , these two devices are not the same thing also...