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How to sample deep bass sounds?

bltpyro

New Member
We have a tempered glass shower door that makes a really cool deep bass "BoOoOoOoOoM" sound that lasts for about 3 seconds. I currently only have a Tascam DR-40 with only the built in mics. Trying to sample it with this I just end up with a "Thunk" sound that is only about 1/4 second long.

So the question is, what needs to be done to capture that sound? Is it mostly about the mic used? Or the recorder preamps? Or would both need to be upgraded to have any hope of recording this kind of sound?
 
The recorder specs say it is capable of recording as low as 20hz, which is plenty of range for recording bass. Its possible your speakers aren't capable of reproducing the low frequencies the door makes. You can check by analyzing the audio spectrum either with EQ or a spectral viewer like Izotope RX, to verify those low frequencies were actually captured. Its also possible the information is there, just not as loud as you heard. So you would want to do a mastering pass and bring the bass up. Which is a trade off, because you'll also be boosting noise.

You also may be recording from too far away, so try getting right up on it.

Last resort, a cheap contact mic would probably give you all the bass you want
 
I just bought a subkick mic for recording deep bass sounds, but honestly it isn't a magic bullet. Even with the subkick and an AKG 414 as close as I could get it, I still had to EQ and use a bass synthesizer plug-in to get the boom I wanted. There's a free bass synth plug-in called Thump for AAX that works well. (Metric Halo maybe?)

Other mics known for bass are the usual suspects on kick drum: U47 FET, Sennheiser 421, RE-20, etc.
 
You could also try a PZM mic (pressure-zone-mic) aka hemispherical, aka Boundary.
Last one I used was a Shure Beta 91 for doing some sound design multitrack recordings.

Some things to keep in mind when trying to capture ultra-low frequencies:
  1. Low frequencies = pressure; whereas higher frequencies = waves.
  2. Think of the environment you're in. For interior rooms, the room is a component of the speaker when thinking about playback. If you know anything about placing a sub in your mix environment, then trying to capture low-frequency content you'll want to experiment with positioning your microphones in a similar matter.
  3. To elaborate on #2: because low frequencies = pressure, and the fact that you're in essentially a box, you will run into "nulls" where the pressure dips. Finding the sweet spot where the low frequencies peak can be done by watching the metering on your recording device. Move around the room while monitoring and take note of the dip in amplitude (a null) and rise in amplitude as you find that sweet spot.
@JunoVHS brought up the excellent point of playback and monitoring. For maximizing the sound to become audible on less efficient systems, you can always experiment with mixing tools like harmonic exciters - anything that saturates or drives overtones in the audio content that are even or odd orders above the fundamental tone thus making the sub-frequencies "appear" to be heard and not just felt.

Tools like Waves MaxxBass are one such tool, and waves just introduced Saphira as well. The opposite would be sub-harmonic generators like Waves LoAir which "generates subharmonic content by lowering and filtering designated audio content by one octave."

I find that contact mics can be great in certain situations. If you really want to grab the impact and sustain, contact mics do not have much high-end fidelity but can really grab the true kinetic energy of the impact and sustain since it's direct transfer and transduction of the energy and not passing through the elastic medium of air and interacting with the room/environment. Just beware of your positioning and placement to minimize mechanical noise like the cable or connector touching or vibrating sympathetically with the glass door :)
 
Awesome, thanks for all the great info! I will try to do the best with the equipment I have first before I go and spend tons of money on mics. Some of those are dang expensive! If I were to get just 1 mic to start out for low frequency sounds, any recommendations on one that wouldn't break the bank? The DR-40 does have XLR with phantom power if that makes a difference.

Would the same mic also be good for ambient stuff?
 
I would look into a condenser mic with a 1" diaphragm and switchable patterns (at least cardioid and omni). Omni has better bass response than cardioid, and would be a good ambient mic as well. I bought a used AKG 414-XLS for under a grand, it's popular for percussion and just a good all-around mic to have. You can also look at mics from Rode, Audio Technica, Neumann, and many others in that price range. You can buy large diaphragm mics way cheaper than $1k, but that seems to be where the quality starts to get good. I'd rather have three great mics than 20 cheapos for the same price.
 
Ya, for me this is just a hobby, so anywhere even close to 1k for a mic is way too much, as nice as they might be. I may just have to settle for the built ins.
 
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