# PCC vs. PZM preferences



## Chris Chapman (Jun 15, 2010)

I've been using Crown PCC160's forever for border mic/floor mic applications. A friend of mine said I should consider PZM's as an alternative.

I need to replace 2 160's this year so I'm looking at alternatives. I have heard some good stories of using 2 PZM's back to back as an excellent stereo solution for house mics as well.

Thoughts?


----------



## bishopthomas (Jun 15, 2010)

It's been a while since I checked so I could be wrong, but I believe the PCC160's are cardioid, while a true PZM is omnidirectional. Depending on your need one could work better than the other (PCC160 on the lip of the stage, PZM's upstage in scenery). I'm with you, though, been using PCC160's for years and never had the desire to try a true PZM as I always got decent results from the Crown mics.


----------



## blalew (Jun 15, 2010)

Small quibble... PZMs are hemispherical, not omni. They work well as part of set pieces or on tables, under closed piano lids, etc. Here's an amazing array of uses by the 'king' of PZMs - Crown - includes a lot of interesting diagrams utilizing plexi to pick up sounds, showing the basis of the amazing SASS mic:
http://www.crownaudio.com/pdf/mics/127089.pdf

At the very least, interesting reading.


----------



## DaveySimps (Jun 15, 2010)

I think this is a case of the right tool for the job. Both have very different characteristics. Neither is an exact replacement of the other. You would not use a ERS to do the same job as a fresnel. 

In my personal opinion, I would stick with the PCC's for your floor micing applications. Since you are looking for a replacements, I recommend the Bartlett TM-125C. Make made by the same guys who invented the PCC for Crown, but with a lower price, and improvements. 


~Dave


----------



## mixmaster (Jun 16, 2010)

It's my understanding that PZM generically refers to a type of mic that relies on physical contact with a hard boundary to transmit the changes in air pressure (sound waves) to a transducer. Essentially the plate on the mic, and the surrounding hard surface, like the floor, becomes part of the element. It's also my understanding that this technology involves or cause a phase shift. depending on the relationship between the size of the boundary and the wavelenght of the sound. I believe a basic PZM could is considered to be an Omni pattern, because in free space it has no front or back and even sitting on the floor it picks up sound from upstage as well as downstage, left as well as right.
Crown's PCC takes the basic PZM technology a step further by altering (reversing?) the phase of the signal and by using a cardioid pattern. The name of the mic stands for Phase Coherent Cardioid.


----------



## museav (Jun 16, 2010)

PCCs and PZMs are both boundary mics.

"PZM" is addressing the Pressure Zone Microphone concept and while Crown has a trademark on both "Pressure Zone Microphone" and "PZM", the patent on the concept expired in 1999, so there are other mics using the same concept, however they can't use the trademarked terminology. The actual concept involved is a mic element facing and parallel to a large 'boundary' surface. By getting the element close enough to the boundary surface, in the pressure zone, any reflections off the surface have a relative phase to the direct sound that results in summation up to higher frequencies, the small distance between the element and reflecting surface pushes the frequency where combfiltering occurs up high enough to not be a factor. This means more gain from the summation and less problems with combfiltering than traditional microphones on a stand.

The PCC uses a cardioid element mounted perpendicular to the boundary surface. By keeping the element very small and located very close to the boundary surface, the resulting interference from reflections also occurs at very high frequencies. This same general concept is often applied when measuring loudspeakers or speaker systems, the measurement mic is place very near a large reflecting boundary surface in order to minimize the effect of 'ground bounce' and push the resulting interaction up to frequencies above those being measured.

I've used the Crown SASS with success many times as a stereo ambient or archival recording mic by mounting it to a balcony face or ceiling 'cloud' in theatres and concert halls.


----------



## 3dB (Jun 17, 2010)

Chris, you didn't mention whether you have an orchestra pit or not, but a mic such as the PCC-160 would arguably be a better choice in that respect as well, due to its directional characteristics. While it does have a small rearward lobe due to its supercardiod (half-super if you like to cross t's and dot i's) pattern, it still has enough rearward "rejection" to aid in tuning out the orchestra somewhat while providing a more focused frontal pickup area (than an omni/PZM). In the event that picking up sound from the pit is a problem, pit sound can be minimized further by placing acoustical foam behind the rearward portion of the mic. Crown suggests a 2'x2' section of 4" Sonex postioned about an inch behind the mic. 

Best of luck with your project.

Regards,
Mark


----------



## TimmyP1955 (Jul 5, 2010)

For upstage use, I can't imagine a PZM working well. A PCC is often of limited use (but our exceedingly lively room may be the cause).


----------



## brubart (Oct 14, 2014)

DaveySimps said:


> I think this is a case of the right tool for the job. Both have very different characteristics. Neither is an exact replacement of the other. You would not use a ERS to do the same job as a fresnel.
> 
> In my personal opinion, I would stick with the PCC's for your floor micing applications. Since you are looking for a replacements, I recommend the Bartlett TM-125C. Make made by the same guys who invented the PCC for Crown, but with a lower price, and improvements.
> 
> ...


The TM-125C is now called the Stage Floor Mic C, and it is available from www.bartlettaudio.com


----------



## brubart (Oct 14, 2014)

mixmaster said:


> It's my understanding that PZM generically refers to a type of mic that relies on physical contact with a hard boundary to transmit the changes in air pressure (sound waves) to a transducer. Essentially the plate on the mic, and the surrounding hard surface, like the floor, becomes part of the element. It's also my understanding that this technology involves or cause a phase shift. depending on the relationship between the size of the boundary and the wavelenght of the sound. I believe a basic PZM could is considered to be an Omni pattern, because in free space it has no front or back and even sitting on the floor it picks up sound from upstage as well as downstage, left as well as right.
> Crown's PCC takes the basic PZM technology a step further by altering (reversing?) the phase of the signal and by using a cardioid pattern. The name of the mic stands for Phase Coherent Cardioid.



Here is an article on omnidirectional boundary mics (such as the Crown PZM): http://cdn.shopify.com/s/files/1/02...a9abcfe4-9502-4ccf-a277-65df0b61c770.pdf?1690

Here is an article on undirectional boundary mics (such as the Crown PCC-160 or Bartlett Audio Stage Floor Mic): http://cdn.shopify.com/s/files/1/0247/3799/files/directional_boundary_mics_1.pdf?1581

I hope that those articles clear up the confusion about these mics' operating principles.


----------

