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Uses for a boundary mic?

Discussion in 'Recording' started by FootPrints, Jun 17, 2007.

  1. FootPrints

    FootPrints Active Member

    Hey everyone, my mom just bought a Samson CM11B boundary half omni-directional condenser mic to record board meetings, but they are only going to need the mic a few days a year, so the rest of the time, I am able to use it. I was wondering if anyone knows of any music recording application this mic would be useful for.
  2. jonyoung

    jonyoung Well-Known Member

    Sure, drum overheads, electric guitar amps, room mic, lots of uses. They should be mounted on flat panels or the wall to maximize bass response. Almost impossible to clip because the air molecules in the boundary/pressure zone don't expand and compress like they do in open space, they oscillate in place. I have one of the original Radio Shack PZM's with the Crown element in it that I've been meaning to mod so I can use phantom power from my board. I've used it on guitar amps, and it's the most accurate mic for that I own!
  3. RemyRAD

    RemyRAD Guest

    Jon, I have 8 of those Radio Shaft PZM's. I've never found a decent modification that would allow those microphones to be phantom powered without hum. Let me know if you find any?

    They do have balanced outputs! All one needs to do is remove the 1/4", unbalance connector and you will find a red, white and shield wires. Just stick on an XLR connector.

    An improvement in signal-to-noise and headroom is possible by replacing the 1 1/2 volt AA battery with 2 EverReady 6 volt, alkaline batteries. The specific model number, I can't remember offhand but the 2 of them, take up the same space as a single AA battery, empowering the microphones with 12 volts. Just make sure that you remove the batteries when finished and for storage, because at six bucks apiece, they ain't cheap.

    PZM's and boundary microphones look similar. Are mounted and used similarly but sound significantly different from each other.

    I've used 2 on the floor to cover an entire drum kit. On walls for audience microphones. Taped under the lid of a grand piano. Stuck inside a bass drum. Taped to a microphone stand for a vocal. Stuck on the front of a guitar amplifier. They're cool!

    Enjoying the Pressure Zone. Oh baby. Don't. Stop. Don't. Stop.
  4. jonyoung

    jonyoung Well-Known Member

    Thanks for the insights on the apparent lack of a decent mod, Remy. I won't be ripping mine apart any time soon. Thanks also for the tip about the batteries and balanced conversion. I'm guessing those batteries are lithium photo batteries?

    As I understand it, the capsule on the PZM actually faces the plate, and the boundary capsule faces forward.
  5. cathode_ray

    cathode_ray Active Member

    Yeah, helpful info 'cause I'm considering trying PZM.

    But I really just hang to hear what RAD really feels...

    Lonely but never alone...
  6. TVPostSound

    TVPostSound Guest

    All PZMs are boundary mics, but not all boundary mics are PZMs! :lol:
  7. RemyRAD

    RemyRAD Guest

    TVPostSound, I think I have overstepped my boundaries? Right. Obviously, I can't deal with the pressure and think it's time for me to zone out?

    An interesting piece of information about those Radio Shaft PZM's. I had a couple of Crown PZM's that originally set me back about $375 each, US. When I heard the Radio Shaft version I was quite surprised at the similarity in sound. I just had to know how this, then $30 Taiwanese imitation clone could compare to my $375 devices. So I picked up the phone and managed to get past Crown's customer service/operator to an actual design engineer. This guy told me that Crown did not manufacture their own capsules but actually purchased them from a Taiwanese manufacturer. They were built to Crown's specifications and each microphone was tested and calibrated. He told me that Radio Shaft went to the same Taiwanese manufacturer and purchased a similar capsule in bulk. He told me that it was a crapshoot where, if you're lucky, you might get a good capsule. Out of the 10 Radio Shaft PZM's I purchased, sure enough, 2 sounded like crap. So I gave those to a friend who loved them. I still have my Crown units, which also includes a tie clasp lavalier PZM, which is really cool, especially if you put it on the test of a drummer and 8 of those old bargain babies.

    That Ever Ready Battery, is a six volt alkaline, not lithium-ion. That alkaline version is already 6 to $8 each. I can't imagine what the lithium-ion would cost? Think about it. To power up 8 of those suckers with 2 batteries each, is a fair chunk of change for not a whole lot of hours. I'm sorry I can't remember the model number and I don't have any handy. I don't see them anymore for sale at Radio Shaft but I would imagine a quick e-mail to Ever Ready would get a reply? I modified a couple of the old units to accommodate 1 and 2, 9 volt batteries. It just gets a little bulky at the battery box. I don't use them as much as I used to. Too bad Radio Shaft still doesn't make those.

    The PZM's appear to have a thinner quality to them which I like for House/audience microphones. Although I'll also throw one in a bass drum still from time to time. Since it's not mounted on a large flat surface, the low frequency response suffers so you get a nice bright bass drum sound. I've also had occasion to use those directional Crown PZM/PCC microphones on the edge of the stage and the Radio Shaft units to capture operatic vocals. I thought they worked quite well. But were not particularly pretty sounding on bright tenors and shrill sopranos.

    Pressure Zone Monster
    Ms. Remy Ann David
  8. jonyoung

    jonyoung Well-Known Member

    Remy, I picked up a couple of Duracell 28L 6V batteries that are exactly half the size of a AA.....a little over $8 each, and lithium to boot. I'll be doing evil experiments later this week, heh heh heh......
  9. RemyRAD

    RemyRAD Guest

    That sounds like the ticket! And lithium too, ooooooo.

    I'm all excited!
    Ms. Remy Ann David
  10. TVPostSound

    TVPostSound Guest

    :roll: OUCH

    RatShack paid licensing to Crown, and was allowed to use their (Crown) supplier. When RS got greedy, and went to a cheaper (Mainland China) supplier, Crown pulled their license, thus the new ones aren't even close.
  11. RemyRAD

    RemyRAD Guest

    And only built by the finest Chinese slave children now.

    Would you like egg role with your Chinese slave child?
    Ms. Remy Ann David
  12. FootPrints

    FootPrints Active Member

    So the Samson boundary mic should be able to handle high SPLs?
  13. jonyoung

    jonyoung Well-Known Member

    Yes to high SPL's.
  14. FootPrints

    FootPrints Active Member

    Well that's news, thanks for all of your help.
  15. achille

    achille Active Member

    I have 2 Radio Shack PZM, I modified with XLR and put 2 9V batteries, I take off the plate and fix the mic near the hole of my acoustic guitare (nylon cord)It,s give me a natural sound better then my others microphone, the trik it's to find the right spot.
  16. Kev

    Kev Well-Known Member

    http://www.celestial.com.au/~rosswood/data/images/PZM Mod.PDF

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