What happened to my room acoustics

@mahgister ...Then i put bundle of straws of dfferent diameter and lenght in the rear porthole, all mechanically tuned then to increase bass depth and clarity going from the 85 hertz specs to 50 with great clarity and impact...

Interesting idea! Perhaps you could develop this concept into a customized tube and commercialize it. Whether or not it's an original idea of yours, being the first to own the commercial product could lead to significant success. Thank you for sharing it.

@mijostyn 

For bass reflex or dipole passive radiator (PR) type (like Burchardt S400) of good design speakers, at resonant frequency of the box, the port / PR does most of (If not all) the hard work and the speaker barely moves.  The woofer has less excursion and therefore less distortion.  It really does not need to rely on couplers to transfer the energy to a big mass for reducing the resonance of the speakers as long as the quality of internal bracing is good. 

The problem might be with below resonant frequency of the box, the effect of the port becomes less effective and, when driver reaches large excursions, the port itself does introduce some distortion to some degree.  Introducing couplers imo may help reduce that impact but, at the mean time, the modern software design tools and available port shapes could be used and optimized to minimize distortion as well.

Dipole PR is more efficient rending more precise control for those impact to the box below resonant frequency.  I own seal-box, rear port and dipole PR design bookshelfs.  The bass performance out of good dipole PR designed like S400 is very impressive.  The bass is articulate even at low volume.

It cannot be patented... It is a basic concept of acoustic and the volume and diameter of the straws their lenght must be computed but with many straws it is a bit complex computation for me with the speakers volume but its is easier to tune it by ears ... The numbers of straws and their dimension parameters will differ for each speakers with a porthole  ... Put in simple term: instead of a single inefficient  porthole it is a complex designed  more efficient porthole ...

The concept if you search for it is : Helmholtz resonator ... Any speakers with a hole in particular is an actual Helmholtz resonator ...

Interesting idea! Perhaps you could develop this concept into a customized tube and commercialize it. Whether or not it’s an original idea of yours, being the first to own the commercial product could lead to significant success. Thank you for sharing it.

@lanx0003 ,

Then you would know every bass guitar sounds different.

This issue is not up for contention. It is an easily measurable phenomenon and not a matter of my opinion.

Porting woofers is a design principle destined for the bowels of some museum. It is an antiquated method of pushing the frequency response of a woofer lower and then cutting it off abruptly in the context of a wooden box which in all respects is a musical instrument masquerading as a pipe organ. Only tightly sealed boxes need apply. Edgar Villchur knew this in the late 50's. Today, given enough power and within the physical constraints of the driver, we can tailor the amplitude response of a woofer or subwoofer to do anything we want without any added limitations or distortion. The quality of the sound depends primarily on the construction of the enclosure, how to not make a musical instrument, and that folks is a trade secret. 

@mahgister 

In the late 70's Randy Hooker aka RH Labs. Made a subwoofer that was a helmholtz resonator. It was a passive subwoofer down firing into a slot. It was huge in comparison to modern subwoofers, about 3 feet by 2 feet by 2 feet. They made beautiful if somewhat colored bass. Inside the enclosure the driver was housed in a larger compartment which was slot loaded into a smaller compartment. It resonated at 20 Hz forcing the driver to go down low. It was a pleated 12" paper driver, nothing special. There were no subwoofer drivers back then. 

Helmholtz resonators are the basis of mechanical acoustics...

As you know i used them in my first room a lot ...

Distribution and location matter ...

Now in my second room with smaller speakers , i designed a new porthole for them using different straws tuned for this goal exactly as when we compute the right size of the neck volume and diameter of the resonator body ...

Then you understand my perspective ...

My goal was first learning acoustics then improve my sound without cost ...

Thanks for the information...

My best to you ...

@mahgister

In the late 70’s Randy Hooker aka RH Labs. Made a subwoofer that was a helmholtz resonator. It was a passive subwoofer down firing into a slot. It was huge in comparison to modern subwoofers, about 3 feet by 2 feet by 2 feet. They made beautiful if somewhat colored bass. Inside the enclosure the driver was housed in a larger compartment which was slot loaded into a smaller compartment. It resonated at 20 Hz forcing the driver to go down low. It was a pleated 12" paper driver, nothing special. There were no subwoofer drivers back then.