audio equipment

Autonomous wrote in post #12338597
chippy help me what to buy cause i'm going to b&h today .

Autonomous wrote in post #12338597
i know i'm getting the audio technica lavs channel one suggested, but apparently i need a mixer to go with that?

The problem you might run into is with two lavs you are right at about $300 leaving only a couple hundred in your projected budget.

As such you might consider a basic field mixer such as the Rolls MX34, while not the top-of-the-line mixers they are reasonably quiet and being stereo allow you to pan each input to it's own channel on the 7D, the real down side is they lack any form of VU indicator requiring you to experiment with the levels to have it low enough to prevent clipping. That said once you get the levels correct you can place a couple of witness marks on the panel with a permanent marker and you will be good to go.

http://www.bhphotovide​o.com/c/product/597824​-REG/Rolls_MX34B_MX34b_​LiveMix_2_Channel.html

Wayne

Chippy569 wrote in post #12338578
JMG is right in that cell phone interference is from the RF signals caused from the phone communicating to the tower.

Technically speaking the noise is not the RF but the product of the RF signal being demodulated by a non-linear junction device such as a transistor or a diode within the electronics of the microphone or a improperly soldered (cold solder joint) or loose connection (poor crimp) within a connector or cabling interface or defective cable (partial open).

The actual noise being heard is a product of the transmitter being switched in what is commonly know as frequency shift keying (technically GMSK) which the non-linear junction being non-linear demodulates into an amplitude modulated signal and being AM that acts just like audio hence the noise.

For what it is worth the reason the older “analog” cell phones didn’t cause this type of noise is they utilized a continuous FM 4.5 KHz modulated signal which requires a discriminator to extract an audio level signal from the RF whereas the “digital” cell phones do not transmit continuously being TDM based instead they burst data as they are polled by the BTS at the cell site and it is those bursts once demodulated that make the all too familiar buzzing that people commonly relate to cell phone interference.

Wayne

jmg181 wrote in post #12338613
Again, it is not a matter of balanced versus unbalanced. I see you're in Florida - go to Infocomm this year, grab an engineer from Shure or Sennheiser, and ask them.

Hate to burst your bubble but I have been there and done that and for what it is worth the so called engineers that are there are really sales folks not engineers and I don’t get technical advice from salesmen.

My thoughts exactly.

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I'll ignore your ridiculous behavior and attitude, and answer.

Channel One wrote in post #12339642
Oh by the way note in the photograph the young lady (my friend Joyce Kaufman) is holding a AT&T I-Phone in her left hand, further note how close she holds it to the microphone which is a standard "non-shielded" Electro-Voice RE-20 while using it, now this is something she does continuously throughout her broadcast as she is constantly sending and receiving text messages from her listeners and nary a bit of interference or noise is picked up, that is unless she forgets to turn off the ringer but that is a different matter.

Because its a dynamic, not a condenser mic.

Seriously, don't be silly. Lets also not forget that for an outside environment, or really anything outside of a studio where you've achieved the proper STC rating, dynamic mics are significantly worse in terms of picking up HVAC and other noise, which is why most on-location mics are condensers.

Which are susceptible to the 217Hz gsm pulse most people call "the blackberry noise".

And don't for a second think that the only people in attendance at infocomm are the sales guys.

EDIT: Btw, iPhones are 3G GSM - WCDMA. Different animal.

jmg181 wrote in post #12339801
I'll ignore your ridiculous behavior and attitude, and answer.

At least I am not changing the subject as I go along.

Nice backpeddeling but that is not what you claimed eariler.

Wayne

Channel One wrote in post #12339874
At least I am not changing the subject as I go along.



Nice backpeddeling but that is not what you claimed eariler.

Wayne

I made a claim earlier about dynamic mics? No, my"claim" was that balanced vs unbalanced has nothing to do with the SAW wave that is a tdma pulse.

Your childlike behaviour is noted.

Autonomous, sorry for the threadjacking, I won't bother with this guy further. Have you gone to BH yet to see the options?

jmg181 wrote in post #12339801
EDIT: Btw, iPhones are 3G GSM - WCDMA. Different animal.

That is true and since they utilize QPSK they in theory can cause even more interference then the narrowbanded GMSK, remember the greater the frequency/phase shift the larger the demodulated output from a non-linear junction will be, thanks for bringing that up I love it when someone confirms what I already posted.

Wayne

Channel One wrote in post #12339936
since they utilize QPSK

HSDPA.

jmg181 wrote in post #12339972
HSDPA.

Nice try but HSDPA is a "technology" whiich utilizes QPSK modulation in either 16QAM or 64QAM depending on the s/n ratio, with a high s/n ratio it will run 64 as the s/n drops and the noise floor comes up the technology drops the modulation to 16 to reduce the bit error rate .

You have really stepped out of your league with this post.

You failed to realize there is huge difference between a technology and a type of modulation utilized to deliver that technology.

Wayne

Forget it, no longer poking the troll. Need to stop getting sucked in.

Channel One wrote in post #12339367
The problem you might run into is with two lavs you are right at about $300 leaving only a couple hundred in your projected budget.

As such you might consider a basic field mixer such as the Rolls MX34, while not the top-of-the-line mixers they are reasonably quiet and being stereo allow you to pan each input to it's own channel on the 7D, the real down side is they lack any form of VU indicator requiring you to experiment with the levels to have it low enough to prevent clipping. That said once you get the levels correct you can place a couple of witness marks on the panel with a permanent marker and you will be good to go.

http://www.bhphotovide​o.com/c/product/597824​-REG/Rolls_MX34B_MX34b_​LiveMix_2_Channel.html

Wayne

1 lavs should be good for me though

Autonomous wrote in post #12340320
1 lavs should be good for me though

You're only mic'ing one person? No mixer needed. Mic's for two or more? Thats when you need the mix (when going straight to the camera).

but my question is if im just getting 1 lavs, how can i directly record that audio on camera? does the lavs come with something or something?

Autonomous wrote in post #12340345
but my question is if im just getting 1 lavs, how can i directly record that audio on camera? does the lavs come with something or something?

There a number of adapters which can connect and match the XLR connector of the lav to the 3.5mm input on the 7D, while you are there ask the rep at B&H to provide you with the correct one.

I would also recommend you bring your 7D and a pair of headphones along so you can try the microphone connected to your 7D and see if it meets your needs before you lay down your hard earned cash.

You can record a short clip to the 7D and then with you headphones conneted to the 7D you can play back the clip in camera and see if you like the audio.

Wayne

Autonomous wrote in post #12340345
but my question is if im just getting 1 lavs, how can i directly record that audio on camera? does the lavs come with something or something?

It depends. Some, like the AT Pro 70, are going to be XLR - you can't go straight into the camera, you need to adapt in-between. Other, less expensive lavs may offer an unbalanced line right out.

A lav thats xlr is (generally) going to be a better mic, in terms of design, construction, and quality, than the less expensive models which would go right into the camera. Since there is a degree of measurebating going on, let me say this instead - listen to the mics. I'm sure the guys at B&H have a few options set up you can do a few tests with, and see if its acceptable to you. You can look at pickup patterns, freq response, etc. all day long, but the best way to know if its right is to try it out and see how it sounds.

Just make sure any audio is coming back through the same set of monitors, and at the same levels.

If what you want is a mic without a mixer or adapting inbetween, theres an answer; if the question is whether or not its acceptable, I can't really answer that. If you want to know which approach is better, balanced (XLR) to a mixer, mixer to the camera, hands-down.