Sub placement

Risking redundancy: For my tastes the low notes generated by the sub are part of the musical whole, and I wouldn't hear a proper mix with my head on the floor in the corner. It's easy to get an accurate, musical main/sub blend in a listening space...and not complicated at all. Do not be afraid. Otherwise, maybe you could carefully balance a stack of your main speakers in a pile on top of your sub at the "sweet listening spot", crawl around on the floor until your knees ache and your head becomes crammed into a place where the moon don't shine.

Sub placement is too complicated. Ditch it and get some speakers that slready put out decent bass...
Or, experiment. I think placing one sub just to the outside or right in front of each speaker might be best, try that.
Another option would be to place the sub in your listening chair, crawl around the room, find out where it sounds best and then adjust your monitors accordingly so that they sound best also, in your new listening position on your hands and knees in the corner of your room.
Seriously though, just get some speakers that have decent bass to begin with; if not, you'll always wonder if the sub is just muddying the waters and whether or not it's fast enough to keep pace with your monitors. I liked subs for about a month, then I realized a good set of speakers is all you need for the best bass response (vandersteens made me come to this conclusion, blame them, not me ). If you want really deep, big boom, go with a sub. If you want mixed well, articulate, fast, look into speakers. Just my oppinion.

Another reason why I can't get the "put your head where the sub sounds best" thing is that it takes the main speakers out of the picture...and the sub/main synergy is where the mojo lives.

Wolf_garcia, you are incorrect again. As I have mentioned in one of my previous posts, when putting the sub at the listening position one tries to find a place that is roughly the acoustic equivalent (for the low notes) of the listening chair. That means that 1) the bass will be very similar in the listening chair and in the place where you would like to put the sub, 2) all bass sources (i.e. room, main speaker and subwoofer) have been accounted for. (Only this paragraph is addressed to you Wolf_garcia.)

One has to realize that below 200 Hz, the listening room (and the neighboring rooms too!) has(have) a very significant effect on the sound that you hear in your listening chair. This is because the room can significantly amplify or absorb specific frequencies, i.e. the room modes. In fact, it often happens that when listening to big speakers what one hears below 100 Hz is dominated by the room response!

The main advantage of adding a subwoofer is that one can place the speakers in the position that gives the the best stereo image and most natural midrange, and place the subwoofer in a different place that minimizes negative bass resonances induced by the room.

I really do not want to be condescending and/or impolite, but people should understand that in order to properly integrate a sub into a system one has to understand how waves interact, i.e. the interference phenomenon. It is really not a difficult phenomenon (it is taught in high school), plus one does not need to understand the math to be aware of its consequences. (It is pretty much like with the water, one does not need to work out the theory or look at phase diagrams to understand that water can exist in different phases, e.g. solid, liquid and gas).

Integrating a sub into a system is utterly room and system specific so rendering suggestions on this is tough. Another reason why I can't get the "put your head where the sub sounds best" thing is that it takes the main speakers out of the picture...and the sub/main synergy is where the mojo lives.

I use a similar method as suggested by Polk432, except that I align the subs (2 15" sealed), facing each other from the outsides of the speakers. Basically, you will aim the subs towards each other across the sides and slightly to the rear of each main speakers. I use a Velodyne SMS-1 sub controller to address any issues. This could also aide in mitigating phase issues.

I have used this process for years with satisfying results. Also, the sound stage seems to open up greatly using this method. Observe that a cutoff below 60hz also removes localization issues associated with bass.

Hi Marty, what you report it can certainly happen but it is not the general rule. Sometimes the interference fringes may be less affected when rotating and/or moving the sub. I am sure that you have often noticed while setting up your sub that moving the sub in one direction can induce significant changes while moving the sub in other direction has only a minor effect, if at all. Since one can never predict this, as it depends on the room and subwoofer, it is best to experiment like you have done. However, as I have mentioned in my previous post, this has nothing to do with our inability to detect the position of the source of law waves.

I've used a REL Stentor 3 (a down firing ported subwoofer) for four years and I have set it up in three different rooms. In one of them rotating the sub made very little difference, while in the other two the difference was significant.

NVP,

Not IME. For the last 6 years, I've used a RTA to measure FR at the listening position. If the subs are in a good spot, I get good results irrespective of orientation. There may be small differences, but if you're setting up subs by ear, I wouldn't characterize the delta as significant.

Of course, different rooms and/or different ears might yield a different conclusion

Marty

Marty, the orientation of the subwoofer can make a big difference as the
interference patter in the room, i.e. position of the bass nulls and peaks,
depends sensitively on the relative orientation of the cone (and port) with
respect to the walls.

To be more explicit, because of interference, i.e. the way wave interact, the
bass response is not the same across the room. There are places with very
strong bass, i.e. these are places where constructive interference occurs for
some specific frequencies (the room modes), and also places with very little
bass, here destructive interference occurs (again for room modes). The
position of these bass nulls and peaks in the room depends on where the
subwoofer is located in the room. Thus, by changing the position/orientation
of the subwoofer one is looking for a position that does not give any
significant resonances (constructive and/or destructive) at the listening chair.

In conclusion, because our ears are somewhat insensitive to the position of
the bass source one can (and one should) move/rotate the subwoofer around
in the room in order to improve the bass response at the listening position.

subs are omnidirectional. face the cones any way you like. if the method works for you, it will work without regard to the subwoofer driver orientation

Marty

I am capable of adjusting my sub using years of experience tempered by personal taste and it does not involve my sticking my head on the back corner floor behind my left main speaker while the sub enjoys a single malt and hip magazine on my listening couch.

I agree with Vicdamone and this is how my JL's are set up. The ARO is a very strong piece of software and can't imagine trying to dial subs in with a basic eq and volume control. On another note, if you are using them to only bring in the 40hz and lower then you may not need to put them next to the speakers. But by all means if you are crossing at a higher frequency then I think they need to be an extension of the mains and placed very close to the mains and maybe a couple of inches in front.

Assuming your two subwoofers are getting separate left and right channel signals treat them like extensions of your main speakers by placing them next to, but forward of, your main speakers.

The listening position method is meant for single sub placement and it can be very successful. Unfortunately, those locations can be obtrusive to multi use rooms. Still, if you have the time the procedure can give you another character aspect of your room.

If your subs lack digital signal processing then a product such as DSpeaker may be of great benefit to better integrate your subwoofers into your room and system.

I use 2 M&K KX10 8'' subs with a pair of Lipinski L707 monitors. I place them just behind and to the outside of each speaker and they sound as one. You need to keep the subs away from the amp and rack to keep vibration to a minimum. Best of luck.

Placing sub under your listening chair with woofer cone up will create an extra stimulation of your hips groins and genitalias. Your wife/date/girlfriend may like that idea
:-)

Wolf_garcia, regarding your comment:

The "put the sub in your listening spot" suggestion is ridiculous (but amusing) so ignore that one

You are simple incorrect. Placing the sub in the listening position and then walking/crawling across the room to find the place with the most even bass response, helps one find the place in his/her room that beside having an even bass response it is also the acoustic equivalent of the listing position, i.e. the interference pattern of the low waves in that place is very similar to the one in the listening position. The method is not ridiculous at all, in fact it is based on simple 3-dimentional Euclidian geometry.

It's true...bachelors often put their subs in the middle of the room.

Try right next to your listening position . My rel placed there was invisible sonically . It sounded like the bass was coming from my speakers . I read a book by Alton Everest ? I think that was his name . He stated that and i thought it was absurd , but being a bachelor i can place a sub in the middle of the room !

The "put the sub in your listening spot" suggestion is ridiculous (but amusing) so ignore that one. Your room and tastes are specific to you so the only answer has to be to experiment with placement as there is no magic formula...I just loosely followed REL guidelines and my ears...found an ideal spot (for my tastes anyway) after a while. I do turn my sub up and down a little depending on the recording, and have no idea if anybody else does that...but it's the only "tone control" I have and it's all I need.

This thread may help
multisubsetup

for reinforcement of bass you can put sub facing corners. placing subs is less of a concern if you adjust bass crossover to bellow 60hz. if you need to adjust 80hz or above, you'd be better of placing them both next to speakers.