Subwoofers - Front Firing vs. Downward Firing

Which is best? What are Pros and Cons of each?
Acoustically there is likely to be only a small difference in the bass. The downfiring sub will be close to the floor surface at a high pressure point - so you may get slightly more acoustic output (think how loading helps a horn) - although this will lower the F3 of the design and reduce the sensitivity (need a bigger amp) but the resposne will be flatter. The downfiring will also reduce the audibility of any small amounts of midrange that come through.

If you want to run the sub up higher in frequency then a front firing will have the advantage as you can place it close to your speaker and use it like a bass bin. (if you do that with a downfiring sub then you will tend to smear the midrange)
With a down firing sub you can also turn it upside down and place a board on top (with something heavy on it to hold it down). This will reduce floor bounce anomalies and tighten up the bass considerably. To do the same with a front firing sub you would need to raise it up off the floor on some kind of rigid platform.

Just a consideration.

Ptmconsulting: Your suggestion of turning the down-firing sub upside down interests me. Are you saying that this arrangement generally tightens up the bass some? With an active sub unit, are there any complications (e.g. heat dissipation, etc.) that one should consider before doing this? I’m interested in trying this with an REL Storm III. Thanks!
Bear in mind that by moving the woofer around you are altering the position of the bass driver. This is similar to moving a speaker or raising it on a stand. If your subwoofer is 2 feet high then if you turn it upside down you have rasied the woofer by two feet.

Two feet corresponds to a quarter wave cancellation of around 130 Hz ( a suckout ) - since most subs have plenty of output at 130 Hz then you will get the smoothest response by keeping it downfiring. If you tuck it up against a wall then you'll get the smoothest response.

Of course room modes will be more severe with a wall or corner placement - so "in theory" you can try to play around with position to get the most even response at the listening position by balancing quarter wave cancellation with room modes. In practice this is very hard to do as they hardly ever line up so that they cancel eachother over the sub bandwidth and you lose dynamic range in doing so (the sub is most powerful placed up against a side wall or corner). Generally a corner placement with down firing sub will give you the most dynamic range and smoothest response but this comes at the expense of overly strong room modes. Often a side wall placement with downfiring and pulled out from the wall where you have the speakers seems to be a suitable compromise - in this case the quarter wave cancellations from floor and side wall are eliminated and the cancellation from the wall behind the main speaker is not severe or deep because of the odd geometry between you and the sub.
As a general rule - as you move the sub out into the room you'll need to use a sharper low pass filter and lower cut off to achieve proper integration and don't forget to add delay based on the sub position to the listener => 1 foot closer = 1 msec of delay (roughly).
Mdrummer01 - I've done this with my REL Strata III to good effect. You may have to turn the volume up a wee bit, but it made a nice improvement. I also suggest moving it out of the corner, if that's where it is now.

Try it, you can always move it back if that's not for you.

Ptmconsulting: Or, you could turn your main speakers upside down -- or perhaps have them firing into the floor -- or maybe straight up. I'm sure that the designers wouldn't have a problem with that. It makes just as much sense.
9rw - please don't comment on things you have not experienced for yourself ... until you have actually tried them. Supposition does not warrent comments. Only experimentation leading to actual knowledge should prompt a response.

So, come back after you have tried it for yourself.

Bob: I'm sure you know more than the engineers who designed the REL Strata III and your speakers. Perhaps you would like to share with us your white papers and other technical credentials. Some things simply do not warrant (note the spelling) experimentation.
9rw - I used to think like you (well, maybe not as extremely self-deluded). But then I actually tried something that was suggested to me and ... it worked, somewhat. That lead me to experiment with other things and, you know what, they also worked sometimes. And sometimes not.

I guess you're not a scientist, where trial and error often leads to new discoveries. If I had to guess I would say you were an accountant playing by the numbers and only the numbers. You're certainly no audiophile, because God knows we've all heard something unexplainable that has changed the sound in a way that is not easily explained.

Be a good sport and try it for yourself (you do own a sub, right? or you wouldn't/shouldn't be posting on this thread). Then come back and let us know if it did or didn't work for you. Otherwise please go away and troll with your textbook answers on some other thread.
Ptmconsulting: Looking at your mid-fi home theater-based rig -- certainly not an audiophile-quality dedicated two-channel system -- I can see why you've come to that conclusion. You couldn't be more wrong about me, my occupation and my credentials. And I sincerely doubt that you know more than Richard Lord, founder of REL. And, yes, I own a REL Stadium III, which is quite a few notches above the Strata. Happy viewing, er, I mean listening!
Mdrummer01: Just keep cranking up your REL. You might consider adding three or four to your system. And try stacking them.
9rw, don't bother with the HT crowd, they live in their own world. One of them told me what my two REL Stadium subs sounded like, even tho he had never heard one. Logic told him. Another told me how high their distortion is. For a real laugh look at HT Shack, where they test subs intended to be woofer downward next to a wall [RELs] in a parking lot with the woofer pointing to the side. They are still living in the 70s when many thought you could tell something about sound from a spec sheet. One of them commended that while I was depending on my own experience and published tests my opponent was using the HT tests and spec sheets, which were obviously better. They seem determined to repeat every mistake that has been made in the last thirty years. One of them told me if I would step outside the "Audiophile" crowd I would realize that bi amping with 2 amps gave no advantage whatsoever over using one identical amp. There are 2 separate worlds on Audiogon and they intersect only marginally. As for myself, I chose to remain a member of the "Audiophile" [AKA Reality Based ] community.
For a real laugh look at HT Shack, where they test
subs intended to be woofer downward next to a wall [RELs] in a parking lot
with the woofer pointing to the side.

FWIW - Ilkka Rissanen, who conducted those "laughable" tests,
recently got a job working in the research department for
[url=]this[/url]pro audio
manufacturer. The bad thing is that working at Genelec gives him access to
a top notch research laboratory equipped with the very finest measuring
instruments in the industry (Klippel Analyzer, Audio Precision, MLSSA) and an
anechoic chamber. I suspect even Genelec still go outside from time to time
to make calibration measurements in a halfspace (parking lot) or suspend a
speaker from a crane and then repeat the measurement to get a calibration
for their chamber...just as Dr. Floyd Toole used to do at Canada's National
Research Council Laboratories before he got a VP job at Harman (since

Definitely a different crowd.
Allow me to paraphrase the great mathematician David Hilbert. There is no conflict between HT and music reproduction, there will be no conflict between HT and music reproduction, there CAN be no conflict between HT and music reproduction because there is NO CONNECTION between HT and music reproduction.
I personally like to take two down firing subs, placing one on the ceiling above me- firing down at my head - and another under my chair, firing upwards. This makes me happy.
Anyway, with front firing subs, I like to set two of them on opposing sides of my head like headphones...of course one is set a little louder, cause my wife yells into one ear more than the it balances the sound, and stuff.
BTW, what's a subwoofers?

Always enjoy your articulate and fact filled responses. I learn something every time...

9rw - home theater based mid-fi? Your ability to read is clearly as bad as your ability to (not) listen.
Here is an anecdotal explanation on why downfiring gives a smoother response in the 100 to 300 Hz range. This is quite an old discovery. The technical explantion is "quarter wave cancellation", which I gave above.

I checked out REL's design (uses downfiring). Richard Lord uses a 12 db/octave filter on the sub amplifier close to the corner frequency of the sub. This is very clever. It allows him to make a small subwoofer sound musical. Small boxes have higher Q (resonance) which is the main cause of HT boomy sound. By rolling off the driver before it hits resonance means that REL can maintain low Q across its output bandwidth even in a small box. The compromise with this design is that the main acoustical output is below resonance and SPL output is limited and distortion will be higher than alterantive designs. The added benefit is that the natural roll off below resonance will tend to integrate better with the in room bass boost and furthermore the 12 db/octave roll off from the amplifier will mate very well with most full range speakers. All this to say, REL makes a sub that will be highly musical (low Q) and one that integrates well with full range main speakers in a convenient small package. It may not kick the proverbial butt of the JL F113 in measurements and pure SPL output but for many audiophiles with full range speakers it may immediately work much better for them in their room from the get go. REL's design is less suitable for use with small satellite speakers. YMMV
Shadorne, you are quite correct about the REL subwoofer designs (or at least the early ones).
Having had a REL Stadium II for 10 years, I found it integrated well with my full-range speakers when run from the main speaker terminals (in other words, allowing the main speakers to still run full range).
When trying to high-pass the main speakers through the REL, the degradation in sound was significant.
The Stadium !!s however, in my room didn't go much below 40 Hz, and when I added the Halcro DM58 Monoblocks to my system, they managed to drive my full-range sealed-box speakers (with 12" paper woofers) down to exactly the same 40Hz?
I now have 2 Vandersteen 2Wq subwoofers with their truly transparent passive high-pass filter and get +- 3dB down to 32Hz.
My room simply won't produce audible sound below this although I do hear pressure waves at 25Hz though probably -10dB?