Subwoofers - Front Firing or Down Firing - Which Sounds Best?

I think you will probably find every sub added brings improvement. My initial plan when building my DBA was to sell my Talon Roc to offset the cost of the four DBA. So when the subs went in the Talon went out of the room. The four were amazing! But then just being curious I decided to try with 5. The Roc went back in. Wasn't expecting too much. The literature after all says going from 4 to 5 should only be a very small improvement. What I heard though, or more accurately what I felt, was not small at all! Most amazing of all was the definite feeling that the bass I was getting with 5 was so much lower than anything I ever felt was coming out of the Talon at any point ever.

I think what happens is any one sub on its own, it does go very low but because of room resonances does so at a much reduced level. Then we get a double-whammy because of the way human hearing works, Fletcher-Munson equal loudness counters rise a lot at low frequencies. In other words really low bass has to be quite loud in order to be heard at all. We simply aren't that sensitive to it. But then the instant it crosses that threshold where we do hear it, wow! Impressive!

So more subs increases the lowest frequencies to where we can really hear them. 

noromance: I know you have a lot of concrete in your rack. But if it's sitting on bouncy floors, what then?

Well what then is mass equals inertia. That much mass simply cannot be moved very fast without a great deal of energy. Way more energy than a bouncy floor. That much mass can only be moved slowly. The effect of massive concrete and damping sand combines to drive all energy into a very low fundamental resonance frequency range. You can see this in action. Stamping or jumping on the floor does move the rack. But it moves very slowly, and very subsonic, around a few Hz.

The response of this massive rack on a suspended wood floor is actually better than a lightweight rack on a solid concrete floor. Because the lightweight rack is subject to vibrate from acoustic energy. Also I lived for years on concrete enough to know even concrete slab can still move and if it does the lightweight rack will transmit that energy right up to the table. A massive rack will absorb and dissipate that energy into its mass.

So that's what then.
btw, I never have recommended "using any old subs". What I have said is they don't need to match, and more is better than few. Which is true.

Nix the down firing. That produces the most floor interaction which muddies the bass and obscures the midrange most especially with the suspended plywood floors found in most modern construction homes.

Interesting. Except mine fire right into the walls, as do Tim’s, as do all of Duke’s, and there is another very similar DBA design that fires down into the floor. The one thing they all have in common is exceptionally clean, clear, articulate and fast bass. The opposite of muddy. Oh well. Think and is don’t always agree.

You can’t have a good turntable rig on suspended floors. You can bolster it and reinforce it but there’s no beating 5" of concrete.

Okay. If you say so. But who says it has to be in the floor? And why only 5"?
https://systems.audiogon.com/systems/8367

That's where I was. Had one Talon Roc sub that seemed to do everything right, except it just wouldn't go low. Exactly like yours, it was just way down at those low frequencies. It is, or was at the time, a really highly regarded and powerful sub. Oh well. 

The solution was to add more small subs. With those the bass extends so low and flat and articulate its hard to believe. Its not just that there is more volume and deeper, there is definition and character way beyond anything I ever even imagined was there before. Its not me, and its not my subs. All the guys who have done this have the same experience. Its the DBA. Just get more subs. You will see.

Its not the manner. Its the frequency. At low bass frequency the wavelengths are as long or longer than the room. So long that no matter where you put the sub or what direction the sound travels out and reflects and can even return all the way back to the sub even before one full wave cycle.

Then add onto that the fact these low frequencies do not even register on human hearing at less than a full wavelength.

Put it all together, this is why it doesn’t matter where the subs go relative to the stereo speakers. Because timing is not a factor. Cannot even be a factor!

What is a factor are the room modes. Room modes happen because the room is smaller than the wavelength. So they bounce around and reinforce and cancel. This is why people find it so hard to figure out where to put a sub. They have to keep moving it around trying to find the one spot where it gives the smoothest bass. Then they get confused and say its coherent, or matched, or synchronized, or integrated, or whatever. They got a million terms. None of which is right. Because they are all based on the same false understanding, the one that applies to short wavelength midrange and treble not low bass.

This is why "you know the answer" dweller is multiple subs. Multiple subs allows you to place them in different locations around the room. Each sub in each location has its own lumpy bass response because of the modes. But each one is a lot smaller because each one puts out less bass because there’s more of them. So they all average together into one extremely smooth bass response.

This cannot work with EQ. All EQ can do is make bass smoother at the one place its measured- but at the cost of making even more bass somewhere else. This excess bass hangs around until it fades out, in the meantime muddying up the bass. So you pay big money for GIK trying to soak up the excess bass you paid big money to create with the EQ. This is the old school solution still being promoted by people who can’t be bothered to learn something new.

Buy whatever sub puts out the most bass for the money. Buy as many of them as you can afford. Put them in different locations around the room. Point them whatever direction you like. Just so there’s at least four of em.

The gift that keeps on giving-

But I Still Want a Subwoofer! That's fine, get one.

Yes, I actually bother to read such drivel. Otherwise, how you gonna know its drivel? We read him so you don't have to!

You know the answer: which sub matters far less than how many. They can be upfiring, downfiring, tubes laying sideways firing or mounted up on the wall ceiling firing. Just as long as there's four firing. Then your 20-ish range will no longer be very rare, but consistent and true to the recording.