Subwoofer PLacement ?

I used to have very little leg room and couldn't put the sub below so what I did is I bought a new desk with a lot of leg room and put my sub down there.  Kicking the sub once or twice wouldn't damage the sub (at least you can't hear the difference or unless it's a cheap sub). Just make sure to keep your foot away from the sub  
 
People have different spots where they put theirs to their liking.
 
Here is a thread with the same subject as yours: http://forum.cakewalk.com/tm.aspx?m=378626

The sub does not have to be centered between your main speakers as long as the crossover frequency is below 80Hz.

The ideal location is something you'll have to determine by trial and error - and measurement. Just avoid putting it in a corner or very close to a wall. Beyond that, every room and every sub is different.

BTW, the best book I've ever read on this subject is "Sound Reproduction" by Dr. Floyd Toole. Of all the books in my library, none has been more thought-provoking. I have read it three times, picking up something new each time, and I still refer to it often. Highly recommended for any serious student of sound.

Put it where you want, and listen to a series of mono, low frequency sine waves (below and a bit above the cutoff frequency) and see if they sound off center.

Low frequencies are pretty much omnidirectional below 300Hz. Studies by Dr. Toole showed that the threshold at which we can detect directionality is around 80-90Hz. What this means is that your subwoofer will fill the room with sound regardless of where you put it, even if it's behind you or off to one side.

The biggest problem is that the long wavelengths (relative to your room's dimensions) guarantee that the sound will not and cannot be uniform. The sound waves bounce off the walls and meet themselves, sometimes colliding when both the original and the reflection are in phase (constructive interference) and sometimes when out of phase (destructive interference). Consequently, the sound pressure levels at various points in space vary radically.

You can easily demonstrate this effect by playing a low-frequency sine wave through your sub while you walk around the room. You will clearly hear the volume go up and down as you move about, sometimes almost disappearing altogether. It's not unusual to have a 20, 30 or even 40db variance! Obviously, this is very bad for making mix decisions, which require an honest frequency response from your speakers.

To a limited extent, you can partially compensate for this effect through "room EQ" or "room compensation". If a particular frequency is in constructive interference mode at the mix position, you can turn that frequency down. Of course, doing so will also turn that frequency down in other parts of the room where it's in destructive mode, exacerbating the problem at those other places.

And any frequency that's in destructive mode at the mix position cannot be fixed through EQ at all because turning that frequency up also increases the amplitude of its reflections. You could crank it up to lethal levels and there would still be a null wherever that frequency meets an inverted version of itself.

To a limited extent, you can partially compensate with bass traps. The idea is to absorb the bass energy so it doesn't bounce around and cause interference. Unfortunately, this just isn't practical in a small room because the trap itself would have to be five feet thick. Tuned resonators can target specific frequencies but they are expensive and you have to really know what you're doing.

Reality: in small rooms, low bass will always be a problem. It's why some folks argue against having a subwoofer at all and defer to a separate mastering facility to figure out their low-end mix EQ. Other things you can do to mitigate it: use headphones, listen to mixes in the car, or employ visual aids like SPAN and Har-Bal.

So the unfortunate answer to the original question is that all you can do is place the sub somewhere where it won't be quite as bad. It's going to be bad no matter what you do.

In my studio, which, BTW, is not an acoustically treated room. Basically I put my speakers where I had room for them. And one of them is even inside of a cabinet of sorts. (you can see it in my pics on the web site...MC4 page) I know that's not supposed to be.... but you gotta do what you gotta do.

So I added a 10" sub some time back and was faced with the same problem. Where to put it?  So I opted for the floor, behind me. It now serves as the stand for my boogie amp as well.  It sets along the wall, firing about 2' to a cabinet, along the wall, with much open space behind it. The stairway opening is behind it and there are open railings around the stairwell.  ((This got me to thinking, and maybe I'll experiment a bit and turn it 90 degrees and fire it into the room and see how well that works. ))

It works well in that position. I do notice that when I slide back about 2 feet and towards it, mostly when I'm working with someone else in the studio, the bass from the sub is overwhelmingly strong. So, my assumption is that I have entered the point where some standing waves are peaking. Moving just a few feet (2') takes me out of that peak point.

So.... if you are limited in the places and space you have to place the sub, just place it where you can. then play back some music that you know and make the adjustments to the sub's level.

I have heard others say put the sub where you will sit, and then move around the room, near the floor, to find the sweet spot.  I didn't use that method, but the sub does seem to be in a sweet spot where I put it. I have made some adjustments to the crossover and to the level so that it sounds right to me when I'm setting in the chair mixing.

Nothing here is done scientifically, and I'm imagining that some of you are pulling your hair out at my explanation or shaking your heads sadly......

Put your sub at ear-hight at the listening position. Pay a sweep through your system and crawl about the floor at sub-height listening for where you hear the greatest "clarity" and definition. Place the sub at this position.

Rough and ready, but it can work.
FS

Put your sub at ear-hight at the listening position. Pay a sweep through your system and crawl about the floor at sub-height listening for where you hear the greatest "clarity" and definition. Place the sub at this position.

I gave that exact same advice for years and even used that technique myself. I had to stop suggesting it when I later discovered that it doesn't always work. (Or to be more precise, it only works reliably in rooms that have no walls. Which is to say it's unreliable in any normal room.)

I still think it's worth a try. Just don't become conflabergrated when the sub doesn't sound the same after swapping the chair position for the ear-at-the-floor position.

Fearful Symmetry


But,I'd probably advise folk with no treatment to avoid subs anyway as it's probably only going to make things worse. Tricky things subs.
FS

Not necessarily. I have an untreated room. It just takes a careful ear to get it as close as one can.

Unless you have a dedicated space, that can be built to spec, most of us must deal with what space we have.  Our mission is to make that limited, untreated space, which often does double duty, as good sounding as we can so the product we produce in it is as good as is feasibly possible.

Listen to the songs in the songs forum. Knowing that many are operating in less than optimal sounding spaces, is a testament to the ability to adapt and overcome those limitations.

My sub is mostly for me....ear candy so to speak. Although it also helps me to hear what's happening near the bottom of the mix quite well.

Yeh, that's not very reassuring, is it...knowing that every time you sit down you may hear the mix differently.

Reference monitors are directional by design, because they're meant to be listened to in one spot only, and designing a speaker for wide dispersion necessitates some sonic compromises. Consequently, many nearfields exhibit a very narrow "sweet spot".

My ADAMs definitely suffer from this. The high end drops off dramatically if you're not sitting directly in front of them. But it's a tradeoff I accept because the speakers are otherwise very accurate. Mackie, OTOH, proudly advertises a super-wide sweet spot, but mixers complain the Mackies sound too much like hi-fi speakers and don't translate well. Always a tradeoff.

I believe those MA-15Ds are meant to be used at close distance, closer even than the standard 3' rule of thumb. You may find that they work better at 2'. When I listened to them I remember having to get really close. They are severely underpowered, for one thing.

you , of course ; need to spend some more $$$ on this !!!


http://www.rationalacoustics.com/pages/Smaart_Landing_Page



Not to hijack ( well , sort of !)

But does the book flipper mentioned say any thing about speakers that use ports to extend the bass reproduction lower ?? I have been reading Mike Seniors new book , and he seems to think life for use pro-sumers  without a killer treated room would be eaisier if we stay away from ported monitors AND subs!!

My plan is to bring them a foot closer to each other and face the speakers toward where I am sitting (in between the two speakers and not facing the back of the room). Do you think this will be ok for mixing?

Yes, I do. With caveats.

You are going to have difficulty with bass, that's a given, and only partly because your speakers are bass-shy. Even if you add a subwoofer or upgrade your speakers, you'll still be working in a small room. Even if you add acoustical treatments, you'll still be working in a small room. No matter what you do, you'll always be fighting small-room acoustics.

That's the bad news. The good news is that despite popular obsession with bass, it's not the most important aspect of your mix. It's really all about the midrange. Many mixers use midrangey speakers such as Auratones specifically to avoid the distractions of the spectral extremes and concentrate on the all-important mids. So yes, those speakers will serve you well for mixing - mostly.

Make use of visual aids such as SPAN to help out with the low end. SPAN can't tell you what sounds good, but it can tell you if you're in the ballpark. Just as it's important to spend time listening to well-made records on your speakers to train your ears, it's also very helpful to observe well-made records on a spectral analyzer to train your eyes.

My main speakers are in the conventional equilateral triangle, positioned on stands slightly over 3 feet away from my ears. A subwoofer sits on the floor. Very conventional.

How far back you place the speakers to some extent depends on the size of the woofers and the size of the cabinet. You might place 6.5" woofers 2.5' to 3' away, 8" woofers 3' to 4' away, 10" woofers 4' to 6' away. (No, those aren't guidelines, just examples.) The minimum distance is largely dictated by the spacing between the woofer and tweeter. The farther apart they are the greater the minimum distance. Another factor is the minimum distance you can put between the two speakers without interference by your video monitors. If you have dual displays that will probably be the deciding factor.

My woofers are 7.25". Experimentation has shown that I don't want them closer than 2' but less than 4'. I have two 20" video monitors, about 36" combined from edge to edge, so my speakers must be no less than about 38" apart. This is why I specifically chose 20" monitors over something larger.

Regarding the link to post #8...Seth makes a curious statement about "bass buildup". Curious because the term usually applies to acoustical interaction between the speaker and adjacent boundaries, not to a characteristic of the speaker itself. Seth's a very knowledgable guy, so I'm sure he knows what he's talking about and perhaps just chose some ambiguous words.

Now, the MA-15D does have an unusual feature, and this may have been what Seth was alluding to, and that is the so-called "bass enhancer" circuit.

The MA-15D's woofer is only 4" and the enclosure is compact, so there is a definite limit to how low it can go - a limit that's dictated by physics, not clever engineering. Roland is curiously coy about just what the frequency response is, but I'm guessing it's only flat to around 80Hz.

The "bass enhancer" is described by various sources as a harmonic distortion module. Distorting the bass is a standard trick to make it sound deeper and louder than it really is. I do it myself with Ozone's harmonic exciter. But IMO it has no place in a speaker system the manufacturer describes as an accurate reference monitor.  Be sure to switch it OFF, even if it sounds better enabled.