fun with pzms

I've had access to a nice pair of crown PZM mics for several years, but only recently have I really been running them through their proper paces.

My interest was really piqued a while back when I decided to mount one to the license plate of my motorcycle and take it for a drive.
 

The fact that the mic could go 80mph with zero wind noise and capture that much punch and detail really impressed me.

Later on, we had a gun recording roundtable on Tonebenders featuring Charles Maynes and Frank Bry.  Charles spoke very highly of the PZMs in his rig for capturing punch and low end there as well.

With all of that in mind, I took the mics out a few times in recent weeks to really get a feel for how they would react in a few different situations.

The first test was the explosive percussive impact test.  Every fourth one of my coworkers lights off some giant mortar style fireworks at his lakehouse, and this year I decided to bring the pair of PZMs and just run those exclusively.

here's what it looked like:


so

That's cool. Here's the unprocessed recording:

Then to hear the boom I used some parallel limiting to make it much louder, and eq'd some more low end into the crushed channel. The main takeaway for me is that the PZMs really have super fast transient response, and very tight low end response.  They really don't require any wind protection even outdoors in moderate conditions, and they caught a surprisingly small amount of the reverberation in the space out at the lake house.

The next test was to run out and get some ambiances with them.  For both of the following recordings I had the mics on the ground about 8 feet apart.

First up was a residential neighborhood at about 8 am on a Sunday. I eq'd out some of the low end to reduce the traffic rumble, and left the high end untouched.

Second was some rain out by a business park.  similar eq to reduce traffic rumble down low.  high end untouched.  Mics were vertical against a wall.

In both of these cases I got what was a very detailed but not very binaural sounding recording.  Very wide and flat compared to ORTF and XY techniques.

After all of this I certainly feel like my PZMs are underused in big percussive recordings, but I feel like I need to experiment more with placement to get the ambient sounding recordings working just right.  I could try jecklyn disk style back to back placement, but before I do that I need to place some of this stuff against picture and maybe try panning it around a bit in the surround field to see if I like what it's doing.

recording my moto: the VTX1300

My motorcycle has been sitting for too long, so I'm going to sell it.

Anytime an audio person makes the decision to sell a vehicle the first question is always "have I recorded it sufficiently?"

In my case the answer was no.  I'd recorded the bike before, but I had never really given it the full treatment, so I rolled it to work last week and set about recording it after hours but before the sun set.

This bike is a Honda VTX1300 with aftermarket Vance and Hines big shot exhaust.  Honda's VTX line has a big, beefy transmission that clunks loudly when you drop into and out of first, and the big shot exhaust really does that distinctive chopper cruiser sound well.

Outside of those two main elements I didn't see much else on the the bike that I felt as though I could record cleanly and at speed.  Tires were pretty out of the question, as was any noise that my feet made on the gear kicks.  My plan was to find the best compromise of drafting placement and proximity to the transmission/exhaust for the onboard mics.

Drafting is a huge deal anytime you want to record a vehicle going faster than about 10mph.  Drafting is the concept of placing mics within the shape and structure of a vehicle in a way that minimizes direct wind exposure when the vehicle is in motion.  No amount of wind protection will stop an 80mph direct exposure to wind, but proper placement will allow for minimal wind protection to be sufficient even at that speed. 

Motorcycles are a little trickier than cars and trucks when it comes to this because they have less surface area on which to mount things and the bodies don't divert nearly as much wind around them, so drafting options are more limited.  This bike is pretty sporty and stripped down, which limited my drafting options further.

I decided to go with the following mic placements, wrapping each mic in a few layers of a cut up T-shirt:

• Line Audio CM3 behind the shock and near the exhaust
• Line Audio CM3 behind the engine block and aimed at the transmission
• Sanken COS11 lav behind the engine, under the seat for general engine bite
• Crown PZM 6D behind the license plate and near the exhaust.

here are the placement pix and isolated tracks of a 60mph run.

 

Of all of them, I feel as though I could have walked away happy with just the combination of the PZM and the Lav (which I almost didn't put up).  Both mics capture a ton of detail, and the PZM in particular felt like the gold standard of someone behind the vehicle moving at speed with a mic aimed right at the exhaust and no wind.  That mic just had tons of low end, and got the quick transient nature of the cylinders just right.

The CM3s acted a little wooly and took on the most wind of all the mics, though they were certainly still acceptable and in the end gave me some interesting lower mid punch that the other two mics weren't picking up.

When they all came together I just about came out of my seat because I heard for the first time a representation of what it really does sound like to be piloting that bike.



Everything is there.  The transmission kicks when I'm climbing the gears,  the whine as the engine lets up, the fluffy kind of release in the exhaust, and all of the power of that bike feels like its there.  The only thing missing is the wind, which is a pretty crazy experience given how intimate I am with the sound of this thing.

Its easily one of the best recordings I've ever made, and I feel like that PZM near the exhaust is going to be my new secret weapon when it comes to the exhaust portion of vehicle recordings.  That thing took zero wind behind about 4 layers of cotton T-shirt even at 80mph on the highway over a 10 minute ride I did the same day.  It was kind of magical.

I had my intern out helping me on the shoot, and he captured a perspective that I'm less familiar with: the exterior by.  He was running a 416 in a blimp and was tracking me as I passed.  These recording also came out great:



In all I got a full compliment of sounds from the favorite moto I've ever owned in about 3 hours of recording (including setup and teardown).

Things never seem to come together this well, so its important to sit back and appreciate it when they do.  Feel free to use these recordings in whatever context you see fit.

Enjoy!