The Reality of Lav Mic Placement
Often times hiring producers and Directors expect me to rely primarily on the lav mic for talking heads. There's a time and place for lav mics to save the day but there's reasons why lavaliere microphones don't sound as good as a properly placed Boom mic. One being the type of mic they are and another being the placement.
The best placement for a microphone is not on the body.
Of course, sometimes we don't have much choice, so, recently, DPA Microphones wrote a very helpful article on Lavaliere Microphone Placement and how some common placements effect speech frequencies. There's a lot to take in there and none of this should be too surprising. Have a look below.
There's just too many variables to be able to say one position is the best position or being able to trust this chart very much for post-production to apply a preset EQ filter. I always say, before we put a bandage on it, let's make sure we've done all we can to straight up take the problem away; in this instance, move the mic to a better sounding position, adjust wardrobe as per wardrobe department's approval before any EQ. Also, very important, this entire article goes to show, how inadequate a lavaliere mic will sound, compared to a condenser boom mic within a few feet of talent's mouths, on axis and operated properly. In case you didn't read DPA's article, the biggest cause for that dip in the yellow band (where speech intelligibility is most critical) is from the microphone being BEHIND the mouth. Certainly a properly placed boom mic will always be IN FRONT of the mouth/source.
Before I quickly dive into each of the listed placements, I do want to also note the peak they all have around the 700-800Hz region. This is not unique to DPA mics, this chart is indicative of lavaliere microphones in general, in response to placement on the body.
That 700-800Hz peak is where most voices, male especially, sound nasally, again, as a result of being behind the mouth and close to the throat.
Compensating for this around the 700-1kHz range on all lav mics is typical, perhaps a bit higher for women, although I don't find it as common with them.
Placing the microphone on the hairline or on hat brims is very common in theatre and is made easier with pre-rigging the mics to talent's wigs. Adam Savage from Myth Busters did a snippet on wig and headpiece miking as part of a behind the scenes series on Hamilton on Broadway. If you're curious to see what I'm talking about, the video is below:
I mostly do sound for film and Television, so it's not nearly as common to put mics in the hair or hats since it's more difficult to hide the wire with the closeups, multi-cameras and a stricter 4th wall. Although there have been a few feature films and a short or two which I was able to rig a DPA 4061 Lavaliere in the hat for the entire production. I'm sure those actors were much appreciative to know they'll sound amazing every shot, pretty much no matter what, as long as they didn't improvise taking their hats off. Winter beanies and hoodies are my friends. I also have nothing to worry about in regards to anything rustling on the mic like it sometimes does when hidden inside the shirt.
The earpiece and headset placements are pretty self-explanatory. I use these for houses of worship, and corporate presentations. Rarely the earpieces, no wonder why those bluetooth airpods sound like junk, but the headsets can be nice as long as the gain structure is properly set with talent and the mic is properly sized and fitted for talent. FYI, this can take some extra time miking talent if you don't want them constantly adjusting it on stage. But there are definitely more factors than just placement of the microphone in regards to making it sound good. Wind protection or keeping it far back enough to not get pops is important and beards are difficult, so again, some extra time with talent to fit it properly and make sure it's secure and comfortable in addition to sounding good with a clean signal going into the board.
In other words, don't underestimate the attention to detail, time and importance of rigging a headset mic.
I use DPA's necklace mics fairly often in corporate A/V. It's usually better than clipping a mic to the top of a turtleneck or sometimes talent has some interesting outfits so having a few necklace mics handy has saved my butt. However, the throat is a really nasty spot to put a mic, so it always needs as much distance from throat as possible, perhaps tape on the back to keep it in place and EQ.
Evaluating that chest mic placement is tough because, working mostly in narrative and reality TV with hidden mics, we can't just simply place the mic in the best sounding position due to wardrobe and/or body shape. Also, sometimes talent's movements make it impossible to either physically place it there, or it would be far too noisy. The placement in DPA's image is very ideal but usually, I put it at least 2 inches lower, to protect the mic from rustling with the clothes. Sometimes it's another few inches lower than that or a bit to the side (deep v-necks, especially on women), or it's underneath thicker clothes than I'd like, which effects the frequencies picked up as well. That's what the high frequency boost capsules are for, at about 10kHz but more ideal mic placement is better, followed by post-EQ.
Either way, you see the lav mic chart above and you see the peaks in that 700-800Hz range resulting in a nasally tone and the large dip in the 2-4kHz range muffling speech intelligibility. Here is a frequency chart of a DPA 4018A supercardioid boom mic. You see how much more natural that will sound when placed/operated properly? A few feet away from talent's mouth, IN FRONT of their face without the risk of talent touching the mic or rustling on the clothes. There's reasons why lavaliere microphones don't sound as good as a properly placed Boom mic.