Making my own full range 20hz speaker vs add dual subs to my floorstanding speaker

[Gahf]

People say that 20Hz cannot actually be heard. A (very) low distortion woofer from my own lab didn't make me hear lower than 30Hz, and even that was hard. If you believe otherwise, which is o/k with me, why stop at 20Hz then?

If using a smaller enclosure the power demand will explode (not really, but square law is pretty strong already ), the cone's mass etc. There is always compromise.

I cannot imagine the room they are going to be used in, but as already stated, room acoustics will most probably be a substantial factor for the overall performance calculation, taking all compromises into account. If possible you might even think of a smaller room as to achieve desired low frequencies with less power using simple pressurization.

A ported design is clearly ruled out due to port size. This opens the door to feedback drive. Basically every sealed box is capable of going as low as you want given the right feed with an equalized signal.

Finally an uncompromising speaker would comprise like a dozend speaker for low excursion in a volume that would allow your amplification to drive them alltogether to the given excursion for acceptable distortion. What are thes parameters in your case? Budget?

I like your idea of the uncompromising speaker. A few months ago I managed to build a similar unit which has now become the benchmark for everyone who hears these speakers, even the golden ears one (yes we are blessed with a golden earned listener whose assessment generally is agreed by REW too). The sub base unit comprises of 4 dual magnet 8 inches sub woofers with a fairly deep excursion, and driven correctly at appropriate gain these do give out one of the best bass I have heard. These go as low as 20hz and in certain specialized music or videos we can feel the rumble. As fineMen says if you can bear a large box (mine is 13*18*48 inches) and multiple drivers driven actively at high amplification and equalisation, you will be able to hear soul stirring music. Here is a photo attached. Am keen to write a separate post which I will perhaps be able to soon.

 

[gnarly]

Hi BrokenEnglishGuy,

Since you're considering the DIY path as an option, may I offer maybe a change in perspective, in terms of the equipment you might want for adding subs?
(and certainly for potentially going the DIY route)

When I first started adding subs to my system, I wanted all the hardware (amps/dacs/dsp etc) to be high spec gear....(in line with your desire not to hear hiss at 3-5cm.)
Then, later after getting into DIY, I found the gear i had didn't always have the functionality I needed for DIY projects, so i turned to prosound gear to provide it.
An example would be the DBX Driverack PA2 posted earlier in this thread. I also bought higher spec gear like a Linea ASC48, and a bunch of OpenDRCs, and Manley & Midas stuff and on and on...

Anyway, the moral of my story is that I now value what I've learned to do with gear far more than the gear itself. I recommend getting whatever offers you the most flexibility in terms of input and output types, I/O routing, crossover and filter sets, delay setting capability, levels, etc, etc.
The Driverack PA2 or something similar would make a good start imo.

There's so much basic stuff to learn (maybe you already know most of it and if so I apologize),
but for me..I've had to learn about balanced vs unbalanced , proper line/amp gain staging (which solve the hiss), optimal xover strategies, when EQ works / when it doesn't, and
more advanced stuff like IIR vs FIR filtering etc)

I honestly think knowing how to use equipement optimally greatly exceeds the presumed sonic benefit of high spec gear.
I vote for the best hardware/software learning platform, that offers the greatest looking forward flexibility you can get.

And that doesn't have to $ cost a ton. It has a learning cost of course...but hey, that's what I'm trying to say has given me the most capability in achieving the sound I want.

A gear/learning example would be a used QSC Qsys Core110f off ebay for $1200-1300. After spending some time with the online tutorials, it will utterly smoke anything you can buy within miles of that price that i know of...in terms of the range of processing functions including FIR , overall flexibility, and I/O capability.
If you find you hear/have sonic issues with it ( i can't) after mastering all it can do,...well congrats ...you're in grad school for sure !! Go buy some high $$$ processing!

Alternatively, is of course the PC processing solution with the right sets of DACs/ amps/etc. I've done that too, and personally found the qsys a lot easier to implement, and play with safely in real time..
But of course, ymmv