A full range speaker?

A 30 hz bass note is 38 feet LONG.

A 20 hz bass note is 56.6 feet LONG.

<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>

"People Ask"

"A 30 Hz sub tone is most apparent (and desirable) with movie soundtracks. Most music doesn’t have much sub 30 Hz information, however there are exceptions such as rap/hip hop/electronica-type music. Also, pipe organ music can go down to 16 Hz (in organs with a 32 ft long pipe)"

<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>
Re: OP

After all, a grand piano’s low A string is less than 8’ long, and to create that tone only requires it to travel a fraction of an inch.

<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>

NO, you’re hearing it generate a tone because of the construction of the cabinet and how the that tone is amplified. There is a WHOLE lot more going on other than a string being struck by a hammer. The length of the string inside offers ONLY a means to tune to the NOTE desired. It could be 24" long and still hit an extremely low note.

The size and construction of the "String" really gets complicated depending on what they do. Bass vs Classical vs Steel Guitar vs Upright vs Grand piano. ALL stringed.

Again SUB is felt and it vibrates your ear drums, BUT hear it.. NO YOU DON’T. SUB means BELOW what you HEAR. What you actually hear is BASS.

No different with above 20Khz, VERY few can hear above 12-3Khz, but leave it out of the MIX you will notice it MORE than you will ever hear it.
The Hi in HiFi, just isn’t there.

Though I’ve seen live performances that shut OFF the bullet tweeters behind people LEAVING the joint, and VERY short tempers flaring.

In any case enjoy your information gathering, do a DEEP dive into pipe organs.. CRAZY some of the huge pipe organs.. 3 stories high..
I’ve seen and herd some Jim Doozies..

Full range speaker, no problem..  http://pointillistic.com/vmps-audio/RMX.htm

6 pairs or LESS are left on this earth.. only 16 pairs were ever made.. I just happen to have a pair.. 20hz-25khz

2 dollars and 22 cents worth

Regards

NO one hears a sub signal NO ONE.. You feel it..

If anyone was to sit in a SUB only room, and then crank the sound, your bones would fall apart.. Just that simple..

On a hydroelectric dam face the turbine rooms, limit the exposure to ALL people.  Same issue in engine rooms on transport ships..

You have to be VERY careful with exposure to low LOUD harmonics.

I read earlier in the thread 15 hz.. LOL. A 32 foot pipe will hit 16 hz in a TUNED chapel/Cathedral ONLY.  Helmholtz tech is used to control and obtain it.. It doesn't just happen in nature..

A VERY well thought out room is the only way to get even close to 20 hz.  NASA's Langley Research Center has purchased two Larger VMPS Subwoofers as a source of 118+ dB, 20 Hz tone bursts. The Larger Subwoofer was the only commercially available system capable at that time.

Nearfield testing can go lower, add a room in the mix, it literally has to be built to work.. 

FEW people could even put up with VIBS like 15-25hz.. Unless you're already NUTS..

<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>

I read earlier, "Whoever said that there's just not that much musical info below 40 Hz was absolutely wack."

"Also recall that "20 Hz" does Not represent the "lowest sound we can hear"

<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>

I'm going to leave the statements above, but I would recommend a little education.. HEARING and SUB in the same sentence. Surely you jest!!

OP AGAIN you cannot hear a sub frequency, you're not getting it..

YOU feel it.. What you call confrontational, I call educational. 

WORDS count and proper nomenclature. I clown ALL the time, does it really bother YOU to be corrected or do you just want to continue to SAY your hearing when in fact your FEELING something..

Honestly I think you got who is confronting who backwards.. 

Maybe I am a little brash.. Let me tip toe away.. LOL YOU got to be kidding.. Romp, pass gas, belly laugh, knee slapping..  

Semi regards, 6 out of 10 on the regard scale we'll see how it goes.. :-)

Good Lord OP I had to visit the (open but closed to any SS person) Social Security office today. I'm not kidding ONLY people who don't have a SS card could get a face to face appointment. I almost went into riot mode.. I'm a EASY going guy.. I like having fun.. I didn't today AT ALL

GD, MF, SOBs $hit! I had to put a nitro pill under the ol tongue. Got me cookin' I almost started bleeding out of my eyes again..

It use to happen when I'd pick up an engine block or something every now and them..

Concentric vs
Single driver
Whizzer AND
Phase Plugs

Whizzer cones have an effect, a lot lower than 7Khz. If you compare the response of the speaker with and without the whizzer cone, not just the frequencies where the whizzer is the sole source of sound.

An 8" driver with 160mm cone and 80mm horn shaped whizzer with and without whizzer, was tested. They found the whizzer cone starts to have a large effect on the off axis response as low as 2.5Khz.

Specifically the presence of the whizzer cone reduced the on axis response from 2.5Khz to about 6Khz by nearly 3dB, but increased the (30 degree) off axis response by several dB. The dispersion between 2.5Khz and 6Khz was greatly improved at the expense of -1db loss of on axis response.

On axis response without the whizzer actually had a +3dB shelf from 2.5Khz to 6Khz, which suggests the main cone of the driver was designed with an increased output in this range (a slight convexed taper)  so the response was balanced once the whizzer was placed.

Above 7Khz the response of the single main cone by itself disappears. At 7Khz the output is almost entirely the whizzer cone.

So technically the whizzer is only acting as a second separate cone above 7Khz, but between 2.5Khz and 7Khz it is still acting as a source of sound as well as a directivity modifier for the main cone.

The improvement in dispersion is so great that at 4Khz without whizzer cone the 30 degree off axis response was -9dB with on axis response (severe beaming). With the whizzer cone in place the 30 degree off axis response at 4Khz was only -1.8dB from the on axis response...

Now think concentric driver with a whizzer for better off axis and phase plug for back wave distortion reduction.

My question is can you still keep the acoustic center of the two drivers and use the correct phase plug to stop the back wave (BASS), from the rear/side walls first reflection.

Hypothetically the HF driver would have to be set inside the phase plug or Open Baffle the HF driver backwards.. (I’ve seen that).. and it works if the rest of the driver system is in a box, bipoled the opposite direction.
(I haven’t seen that)

What I’ve seen and herd though was BOTH sides of the driver were in an open baffle. So it was dipole for the bass and bipole for the HF driver (it had it’s own chamber) and it was facing the front wall..
A nightmare to get the timing right.

The acoustic center only stay aligned, IF the driver and structure are placed in a chamber, I don’t think you could get it to work correctly in a listening room. Maybe.. within 1/2" to get it right..

3 years I worked with the old GRs at a buddies.. 90s. (Super Wedge or something).

He gave up.. I didn’t have much of a choice.

Regards

Concentric is two drivers in one chassis with the center being the High Frequency (HF) driver independent of the outer Lower Frequency (LF) driver. Tannoy speaker drivers.

Read what it says over a few times and it will make sense.. We want it, in your head, not over your head. :-)

Regards