Subwoofers down-firing or side-firing? Why?


Just added down-firing subs (Omega 10", sealed) to my Omega single driver speakers. I could ask Louis, but why do you think he designed them to be down-firing?  My prior REL and Rhythmiks were side-firing (used with very different systems). 
redwoodaudio
Brian Ding at one time offered a down-firing Rythmik model, but discontinued it after coming to the conclusion that the same woofer in the same internal volume enclosure, but front firing rather than down, sounded more impactful.
Here's what Rel says on the topic:

https://rel.net/down-firing-vs-front-firing/

BTW, I couldn't be happier with my Omega DeepHemp 8. Tone, impact, fast, and easy to place. Never asked Louis about his down-firing choice only sealed vs. ported. I'm sure he'd be happy to answer your question and I'd be happy to hear it :-).
I favor a pair of front firing subs located adjacent to the main l/r to create and preserve stereo imaging.

Low bass and the overtones of that low bass is directional, so you get stereo bass working with the imaging and phantom center channel created by equal or varied output from l/r mains.

My 15" woofers were originally down firing from a 1958 Fisher President console on 8" high bronze legs. I inherited it from my uncle who sadly died young.

He had it on carpet. I had it on hardwood floor, The rear mounted ’brilliance’ and ’presence’ controls helped balance the woofer’s output with the mid and high horns in any room.

I designed and had built new enclosures, and faced the 15" woofers forward. I added rear ports, what the heck, let’s get it ’all’. Tilted back for time alignment, project tweeters to seated ear height, and avoid propagation of woofer parallel to the floor. Toed in also avioded propagation parallel to side walls, as well as creating/preserving imaging.

Bass directionality was improved, even more so when I plugged up the rear port which was a youthful mistake, especially my size rooms (3 different rooms)


@melvinjames

Yes, loving my deephemp 10 so far. Maybe it's downfiring to get the most bass out of the smallest cabinet, according to RELs logic. 
I favor a pair of front firing subs located adjacent to the main l/r to create and preserve stereo imaging.
If the subs don't go above 80Hz they won't affect imaging at all. The harmonics of the bass instruments do the imaging, and they will be in the main speakers (unless the mains don't make it to 80Hz- then you have a problem!).


Downfiring subs allow the bass wave to move in several directions in the room at once. The problem you have with bass in a room is standing waves which can cause cancellation at some places in the room and re-enforcement in other places. By having the bass radiate in several directions at once, its easier to place the sub or subs so you can get more uniform bass because some of the standing waves can be less pronounced.

Of course to really deal with standing waves you need 3 or 4 subs. Then you can have really even bass everywhere in the room.
My ML subs are downfiring and placed in opposite corners of the room and are set to work from about 70hz down.
I honestly can NEVER tell they are on, in other words I can never detect where they are by "hearing" bass emanating from a particular corner located sub.
But turn them off?
Who killed the bass player!!

Have never had side firing in this setup so no idea if better but figured that ML know what they are doing........
Downward porting, with a passive radiator solves a few problems.  Add that with side firing active drivers, you get a few things more.  Quicker roll offs, and easier blend between sub and bass. 

 The material used is important in the drivers and PR, paper has great property, in the DOWN firing position, you can pick up on in the forward firing position, but not downward. Woven carbon fiber, is my favorite sounding active driver (it has NO SOUND).

I did find some Alu cones with light enough spider and surrounds that work better with higher XMax drivers, in the Passive position. I also add "More-Tite", non hardening putty, you pinch to get the mass weight correct.  Under your fingernail sizes of adjustment, VERY accurate, for main and sub blending..

The weight and rigidity of the driver cones has a lot to do with the quality and speed of the sound. 

I like phase plugs also, it makes a LOT of difference at the sub/bass driver.  It LOWERS distortion, through deflection.  Because they are outward facing, (even if they are facing the wall), the standing wave doesn't effect the cone face with phase plugs..

The phase plug design shape and length, help a lot also..
I use a bullet shape from 300-1500hz. A  half round, pretty long one from 1-300, and a short flat and sometimes concaved from 20-100hz.. It's paid me great dividends in distortion reduction, bass clarity, and cleanup.

I make it sound pretty rough in application, In reality, I use some pretty precise measurements for lengths and shapes.

Regards
There are so many variables involved, seems like whether driver faces down or sideways is not the major factor... 
In my case (Martin Logan), I did not notice any sound difference so I opted for safety and I use them down firing to reduce any cleaning and/or small children accidents which may happen and destroy the woofer.
I own 2 RELs from a similar era, a Q108MKII down firing 8", and a Q150e front firing 10". They are GREAT subs and work swimmingly together. Bought used at different times for about 200 bucks each...make my own cables out of Canare quad.
According to Louis at Omega, he uses down-firing subs for ease of placement.
I've tried both configurations with the exact same subwoofer.  With downfire, you do hear the bass, but you don't get nearly as much "punch you in the chest" type of sonic impact.
The Sub-x sub from Golden Ear has too side firing active drivers and a top and bottom firing passive radiator. Its much easier to get the placement right.
"....Downfiring subs allow the bass wave to move in several directions in the room at once. The problem you have with bass in a room is standing waves which can cause cancellation at some places in the room and re-enforcement in other places. By having the bass radiate in several directions at once, its easier to place the sub or subs so you can get more uniform bass because some of the standing waves can be less pronounced...."

I believe that is Rel's position on the matter, making for easier integration.  
sub woofers are only meant for HT, sound effects, and parties/HIP HOP/rapp, 
But never ever for real music. 
There is no such thing as a  <<high fidelity subwoofer>>>
a  sub is only for sound efgects = anti musical.
Just thought I'd make this clear.
There is no such thing as a <<high fidelity subwoofer>>>



You are correct it is "High fidelity subwoofer" there are no <<<< or >>>>.

GR research servo bass system, is about as high fidelity as you can get.
Mozartfan? Nothing below 60 hz is considered part of music.
HIP HOP / rapp isn't real music. OK you say so...

"I like big butts and I cannot lie", remember that song? I do, it's music of the most delicious kind... Yea...

Regards...