sub woofer

[harry.mchugh]

does anyone know what i will need to have to make a sub woofer rumble. Like, in a scarry scence or to add suspense and i can make the subwoofer rumble if there is one. Like if i played it in my dvd player which is setup with surround sound and it got to that part my subwoofer would rumble. Do I need software, and if so what kind? Or, can i just get like a .wav file. Thanks so much, I have been wondering this for a while.

 

[Drew Ott]

Don't know the answer but I am also curious.

I don't think there is an "increase bass" setting in most NLEs but, I would assume if you got a deep rumbling sound effect and turned up the volume on just that clip it would work.

 

[SMuir]

Well... for starters you'll need audio material with plenty of energy in the 20-100 Hz range. The exact upper limit of that range will depend on the subwoofer and the crossover frequency, as well as whether you're using a discrete LFE channel (as used in Dolby Digital encoding).

The easiest way to do this would be to plug a sweepable test tone oscillator (such as the one Rolls makes) into the line input on your amp, then sweep the frequency downward until you hit the point where your subwoofer is rumbling nicely. Rolls' test osc is pretty reasonably priced, and this method doesn't require any significant audio editing or recording experience.

If you have access to non-linear audio software such as ProTools, you're options increase significantly. With enough skill, you can create CD's or DVD's with quite complex sub-bass effects.

Synths can create sustained LFE rumbles easily enough. You can also take existing sound effects and pitch them down (without time correction of course) until they sit in the desired frequency, then apply a low-pass filter to knock out the top end.

For recording effects that are primarily sub-bass, I've gotten a fair bit of mileage out of the AKG D112 kick-drum mic. Using one to close-mic the exhaust on a deisel tractor, for example, will give you a nice jaw-rattling LFE track.

I suppose you could also use a bass-extender like the DBX 120A to add sub-harmonics to your existing bass and LFE materials. I haven't used this particular effects processor myself, but I know a few club DJ's who swear by them.

I hope that helps.

 

[Noiz2]

And now for the bad news. Bass uses a huge amount of energy and if your doing a stereo mix with that much "rumble" in it you need to do some careful testing on regular old TV speakers because you might just overload them and make the whole mix sound like shi*. This starts to quickly be one of those "kids don't try this at home" situations.
That said you might well be looking for subsonic sounds (below 20Hz). Use sub-harmonic synthesizers or a synth, or if its for a specific event (someone's head exploding for instance) you might just take the sound and pitch it down a bunch of octaves.

 

[ScoobySounds]

i second the use of a synth to produce the actual noise you're looking for,


The rolls oscillaor mentioned above only produces a pure sine wave, so you'd onloy be finding the resonant frequency of your sub/room/house as things start to rattle around you.

I think you are just talking about trying this on a dvd setup, not an audio editing set up. not sure how you would do it without making the dvd yourself, yes, with software.

I don't think you couls add LFE tracks if you only have a dvd authouring suite, i'm not sure how sophisticated they are, but probably could only do it with audio editing suite, setting up the 5.1 channels of audio, saving it as an ac3 interleaved file then burning that onto dvd with the authoring software.

Thats just how to do it on a dvd, but just for experiments on noise probably just hook it straight to your computer and pitchshift/lowpass stuff.

 

[Noiz2]

Withe DVD Studio Pro you can bring in 6 discrete tracks to make the AC3 stream. If you can set the downmix to exclude the LFE then it should work well on most systems. The stereo fold wont get the rumble but they will be able to hear the rest.

 

[carlone]

Whatever sound you use you need to apply a high pass filter to it. Roll OUT anything above 40hz and all TV or small speakers won't be able to reproduce this sound (that's a good thing). Anybody with a Sub will hear the sound. Don't go crazy with the level (in other words you don't have to turn this sound up extra loud). Bass frequency's down this low (between 20hz and 40hz) are meant to be felt more so than heard. Just a little bit of volume goes along way.

 

[Noiz2]

You mean Low pass filter. You can hear 20-40Hz. Your right that most speakers wont play it but it still uses up headroom. I guess I;m just reenforcing what your saying, don't go overboard with it.

Whatever sound you use you need to apply a high pass filter to it. Roll OUT anything above 40hz and all TV or small speakers won't be able to reproduce this sound (that's a good thing). Anybody with a Sub will hear the sound. Don't go crazy with the level (in other words you don't have to turn this sound up extra loud). Bass frequency's down this low (between 20hz and 40hz) are meant to be felt more so than heard. Just a little bit of volume goes along way.