Dual Opposed Subwoofer Theory?

[Chromatischism]

Previously my way bigger ported speakers were tuned to about 40Hz. That was too high to take advantage of my (!) room to anywhere lower.

Mine are tuned to 12 Hz, but the port gain extends an octave or two above that. Low enough to avoid audible GD. No port noise or chuffing either

 

[fineMen]

Mine are tuned to 12 Hz, but the port gain extends an octave or two above that. Low enough to avoid audible GD. No port noise or chuffing either

Congrats!

 

[Chromatischism]

Congrats!

Thanks to Rythmik!

 

[AlexanderM]

Here is a super cheap dual driver subwoofer. I am prepared to duck. That company also has triple driver subs.

https://www.amazon.ca/PROFICIENT-SYSTEMS-FS8-Dual-Drive-Subwoofer/dp/B016NXTIBE/ref=sr_1_53?keywords=dual+driver+subwoofers&qid=1670432168&sr=8-53

It's backordered, but what a price and Cdn$, for 12" triple driver Sub.

Proficient FDS-12 Protege FDS Triple 12” Subwoofer – Multivoltage

FDS-12 Protege FDS Triple 12” Subwoofer – Multivoltage Proficient Protege Subwoofer Series – 12″. With High back-EMF woofer design: over-sized magnets generating high motor force, experience unprecedented performance at this price. Specs linkage

eversecu.ca

 

[HighFutility]

WinISD is perhaps the most popular bass box simulator, worth investigating

Dual opposed woofers share same airspace typically. Air volume in the box is an important factor that affects the low end behaviour of drivers when long excursion and air compression/movement happens. This will show in spl response of the unit and maximum spl it can give per frequency. Bass reflex tuning depends on box volume and port length, number of radiators is negligible.

Many dogmas and traditions of loudspeaker's bass performance come from era of drivers with short Xmax and poor power handling, and passive designs without use of signal eq or motional feedback. In this millenium we can bend those rules quite a lot (at least for domestic use) simply and with low cost by DSP and modern driver units, driven by cheap and efficient classD amplifiers.

Dual opposed in my eyes best suited for hifi 3-way speakers, as seen in eg. Vivid Audio Giya. Home theater and PA subwoofers aim for very low freq and high spl capacity, which still means very large cabinets and often some sort of horn to maximize efficiency, then dual opposed is not best giving benefit. I have personal experience with a DIY PPSL dual opposed with two sealed boxes side by side, with 15" woofers. A single Hypex DS2.0 easily drives it to intolerable spl in my HT room!

View attachment 104769View attachment 104770

Can WinIsd model DOS subwoofers?

 

[sigbergaudio]

Can WinIsd model DOS subwoofers?

Just add two drivers instead of one. The inherent response doesn't change whether a sub is just dual driver or dual opposed driver.