Subwoofer placement

[David W]

Hi guys

Just brought a sub woofer to compliment my Genelec 1030a nearfeilds and wondering the best place to put it in the studio. I have a large custom console that fits my Control 24 mixer and a row of 19" rack gear on the side.

Would there be any issue with putting it on the console in the middle of the two near fields of should it be on the floor. Only issue with the floor I see is I wont have an unobstructed line from sub to mixing position.

Also how is it best to judge the frequency cutoff point for the subwoofer.

[DarkSky]

For anything under 120Hz or so, the sound is not directional, so an unobstructed line from the sub to the listening position is not needed. The more important issue is phase and whether the sound from the sub arriving at the listening position is in phase with the lows arriving from your left and right speakers.

The simplest way to solve this (at least as a starting point) is to put the sub in the centre on the floor and match up the distance (from the sub to your ears in the listening position) to be the same as the distance from your ears to the L&R speakers. However you will also need to consider reflections, esp if there is a wall nearby, so some adjustments may be needed to get even and tight bass throughout the lower octaves.

[geofflee]

I would have thought that most subwoofers are designed to be placed on the floor. Genelecs usually come with comprehensive guidelines for monitor/subwoofer placement. Always a bit tricky to get right - stupid bass!

[DarkSky]

FWIW, there's a decent article by Bob Katz on subwoofer placement over on the Digital Domain site. The link is:

http://www.digido.com/subwoofers.html

[Kurt]

One idea I read about (Stav?) was to put the sub on your chair, then crawl around the floor, find where it sounds best and stick it there..

If your room is as small/cramped as mine it will be dictated by space to quite a degree.

[The Tasmanian]

Only Stav would come up with an idea like that - that is crazy!
And maybe it works but it still is a bizarre approach. I can't see myself with my head on the floor listening to the sub in the chair.
Ray nailed it with the phase - its probably the most important factor to look at.
If you are right up against a wall then you may have to turn the subs down to compensate for the bottom end corner build-up . Or move your console further away from the wall. (had to do this myself years ago when a sub was added)
Equidistant from your nearfeilds to the monitoring position.
Sub must be on the floor though - that is what they are designed for.
If you have carpet then a stiff sheet of 25mm ply (much larger than the sub) under the console can help in this situation.
The other thing to add here - the more volume you have on the sub then the more your control room problems are exasperated - sometimes it can defeat the purpose of adding a sub.
So in a small room - just a hint of subs is the way to go.

[Linear]

For anything under 120Hz or so, the sound is not directional...

The theory says this, however I think you can still pick where a sub is in a room if it's not centred with the other speakers.

So I would just say that make sure you place it equidistant with your nearfields, and move it around till it sounds good.

Chris

[waitup]

It's funny how little information about placing subs there is... even the AES paper on 5.1 speaker placement is super vague about where to place your sub. The obvious consideration is that the higher your crossover point, the more your ears can localize the speaker, and hence the more you'll want to get it a similar distance from the listening position as your mains. The lower the crossover point, the less you'll have to worry about directionality, so you're more free to move the sub about off center.

I reckon if your sub is really just covering the super low end of your system then just try a few places until you find the spot where the bass is most even. You could do some dodgy tests with some sweeps and an SPL meter or something if you were feeling adventurous.

Anyway, have a good easter weekend t'rockers!!

[audioio]

I think you can still pick where a sub is in a room if it's not centred with the other speakers.

Second this. Had a Genelec sub behind a Control 24 at work. Could definitely tell the difference when we moved it out (and it crossed over at 120 Hz).

[The Tasmanian]

We can feel where bass is coming from through our bodies and our ears can detect vague direction of bass, but when the 2 are observed together it is not hard to detect the direction that the sub is in.
Dead centre is a must I would suggest - or 2 subs (which is better).
The phantom mono image would be confusing with one off to the side - and if off to the side sounded better then my guess is this would suggest serious acoustic issues.
It should sound great dead centre - moving it forward or back to find the sweet spot - and also playing with level.

[David W]

Thanks guy's.

You know up till this post and some internet searching the best I could find was the previously scoffed at idea of placing the sub at listener position and crawling around to find the sweet spot.

The main reason I am going to do this is that a lot of high pass and 40-50Hz stuff can be beneficial to a mix but unless I do some extream boosting it's hard to be confident of what is really happening down there. I really need to hear somewhere around 70 - 60 Hz and lower a little better.

Anyway I will try a few suggestions and hope all goes well.

[The Tasmanian]

Just another thought
I've spent quite a few months at The Grove studios and their subs are at the back of the control room.
About 3m behind the mix position.
With the SSL there would be not a lot of room for the subs, and I imagine that they started behind the console and with tests found them better at the rear.
It felt a tiny bit disconnected from the monitoring position (i was tracking not mixing) - but on further thought triggered by this post, it would be a logical position to try as a second choice if you felt that is was too confusing at the mix position.

[Ben M]

I think building the sub into the mix position seat would be ideal... with a little switch to turn it off when it gets annoying.... or when nature calls.

Would be totally kick ass.

[Kurt]

I bought a couple of bass shakers with the intention of building them into the drum riser at the pub my PA lives in. One day I'm sure I'll get around to it!

Shaker.
http://en.wikipedia.org/wiki/Tactile_transducer

[Kurt]

I worked on set-up at Cirque Du Soleil a few years back, they had one each under the drummer, keyboard player and bass player all fed from the FOH sub send. Apparently all the guys loved being able to literally feel the music.

A drummer I toured with used to put one under his drum throne - felt pretty cool when you hit the kick.
Need large power amps to drive them though.
I've heard of some bands having up to 16 of them under bass risers etc.

[Hookemeister]

Hi David

Once you've decided on the best place to mount the sub, the next thing I would do is run a slow sweep tone thru the sub and track down any panel resonance in the room. Just gradually raise the frequency from 20Hz up to 100Hz, at a reasonable level and you'll be suprised at what starts to vibrate and rattle. Anything that resonates will cause smearing at that frequency and any metal that start's to rattle will drive you nuts.

You'd be surprised how many pro studios install subs and never do this simple test.

Greg Hooke