When and why did the typical floorstanding speaker lose the midrange driver?

[Pharos]

Please forgive me if I am wrong, I do not even have a degree, let alone a PhD, but even the external environment method cannot completely decouple the back emitted wave because the all of the factors are finite.

With enough resources and an acceptance domestically, couldn't we go down to 2Hz?

[Barry]

The idea of an externally mounted speaker in the wall to produce a low frequency compression wave ideally requires the listening environment to be a sealed volume, which of course it is not.

Even so, low frequency waves can be generated by such means. However to have a palpable presence (infra bass is felt and not heard), a considerable amount of power is still required.

[drrdf]

I think most of us have considered it more than once. The principle, provided a true outside wall is selected, (without it having any windows) is really one of the ultimate infinite baffle.

[drrdf]

Pharos: I do not think there would be any point in going down to 2 Hz. Even 16 Hz. is not really a discernible note, but it gives presence. Provided the external wall selected does not have any windows and is a modern double cavity wall, there is no back pressure on the drive units and any "back wave" is radiated externally into the environment. It is thus the nearest thing to a perfect infinite baffle.

G. A Briggs at Wharfedale got close to it with his brick corner reflex, but although it produced infra-bass amazingly it did still suffer from the the anti-phase problem, because it was a Helmholtz resonator. Nevertheless it reduced the cone resonance to 18 Hz and produced this frequency adequately with only two watts of power I believe.

[Macca]

There's a handful of pipe organs in the world that have an 8Hz pipe.

There is one in the old Atlantic City Hall. Apparently the 8Hz pipe in action sounds and feels very much like a large helicopter is hovering right over the building.

[Batty]

Ran my Castle Howards in the back yard at a family gathering and the SQ was the best I have heard from them, they are a 2.5 way 1/4 wave design, one of the drivers is upward facing on the top of the cabinet.
Small drivers can work well, I have tried other speakers, but keep coming back to the 1995 S1 Howards.

[Barry]

There's a handful of pipe organs in the world that have an 8Hz pipe.

There is one in the old Atlantic City Hall. Apparently the 8Hz pipe in action sounds and feels very much like a large helicopter is hovering right over the building.

That's very close to the alpha rhythm frequency of the human brain. Long term exposure to such an external stimulii can cause epileptic fits (in the case of light pulsing at that frequency) and if loud enough can cause loss of bodily control (I'll leave you to imagine what that means). There is a phenomenon known as 'sick building syndrome', wherein occupants (these 'sick' buildings are usually offices) reported feeling unwell after a day's work there. The cause was often traced to air-conditioning units generating low level, low frequency sound.

Many years ago the French looked into the use of infrasound for crowd control. The researchers would have to wear thick protective clothing, making them look like Michelin 'tyre men'. But the project was abandoned because the massive horn speakers used were just too unwieldly for practical use.

[Lawrence001]

I think most of us have considered it more than once. The principle, provided a true outside wall is selected, (without it having any windows) is really one of the ultimate infinite baffle.

I'm not sure most forum members have considered mounting their speakers to the external wall venting to the outside. Happy to be corrected though. Maybe we need a vote

[Barry]

I have never considered it - I'm just aware that some enthusiasts have done so (usually horn loaded speakers, opening into the listening room).

[Pharos]

Pharos: I do not think there would be any point in going down to 2 Hz. Even 16 Hz. is not really a discernible note, but it gives presence. Provided the external wall selected does not have any windows and is a modern double cavity wall, there is no back pressure on the drive units and any "back wave" is radiated externally into the environment. It is thus the nearest thing to a perfect infinite baffle.


G. A Briggs at Wharfedale got close to it with his brick corner reflex, but although it produced infra-bass amazingly it did still suffer from the the anti-phase problem, because it was a Helmholtz resonator. Nevertheless it reduced the cone resonance to 18 Hz and produced this frequency adequately with only two watts of power I believe.

" I do not think there would be any point in going down to 2 Hz", is a value judgement.

"Provided the external wall selected does not have any windows and is a modern double cavity wall, there is no back pressure on the drive units ".

Surely the cavity is finite, and will provide some back pressure, and the cavity volume is also finite.

I think you are missing the philosophical point that there will always be some back pressure, even if it is 10^1000 dB down. World is finite, and hence back pressure can never equal zero.

Similarly, I am sure that the ear does have some sensitivity at 2Hz, and for similar reasons, and it may well be also 10^100dB down, and may provide what you describe as presence.