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Old June 7th, 2008, 11:50 PM   #1
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How to test "Stereo" in ECM-680s mikes

so i gave into temptations and bought the Sony ECM-680s mono and stereo shotgun for the EX1.

how does one test the stereo of this mike?

i try to make a minute noise in the each side, but listening through earphones, both channel recorded the noise. since they are spaced so closely together, just how does one know the stereo effect is working?

also, the noise floor seems higher than my ECM-XM1 as well as ECM-673. some constant low hum. is mine broken?

thanks,

paul
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Old June 8th, 2008, 12:33 PM   #2
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You need to describe both the test and your monitoring setup including camera settings.

XDCAM EX imported into Final Cut Pro is dual track mono (center panned). You either need to pan the channels or use the Modify/Stereo Pair on the timeline clips. Actually if you try to export an FCP timeline to MXF using Sony XDCAM Export command to make MXF, it will then tell you that you must make the track Mono again.

Hum? You may have a bad ground somewhere or something in the environment creating it. You also need to test and adjust the input sensitivity in the EX1 as the mic (many mics) can overdrive the preamp into distortion. I'm finding low frequency wind noise can do that so the input sensitivity adjustment may well depend on the environment.
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Old June 8th, 2008, 08:03 PM   #3
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i tried a pink noise generator, but the test was not systemic, i'll need to have someone run it monday....(will report again..)

as for the hum, it may be the air conditioner 8 feet away at the session.

still, do you use the low pass switch option, Craig, on the 680s?
does it roll off below 100hz or more to reduce the wind and other noise?

paul




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Originally Posted by Craig Seeman View Post
You need to describe both the test and your monitoring setup including camera settings.

XDCAM EX imported into Final Cut Pro is dual track mono (center panned). You either need to pan the channels or use the Modify/Stereo Pair on the timeline clips. Actually if you try to export an FCP timeline to MXF using Sony XDCAM Export command to make MXF, it will then tell you that you must make the track Mono again.

Hum? You may have a bad ground somewhere or something in the environment creating it. You also need to test and adjust the input sensitivity in the EX1 as the mic (many mics) can overdrive the preamp into distortion. I'm finding low frequency wind noise can do that so the input sensitivity adjustment may well depend on the environment.
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Old June 8th, 2008, 11:46 PM   #4
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Paul, I've had nothing but good results (untested!) from that mic which I've had for a month now. It appears to have reasonable stereo directionality for a shotgun, I have really heard NO noticable hum, and the bass response (below 100Hz) is definitely more solid than a couple of Audio Technica mono shotguns that I've used previously. I do, however, await someone of the ilk of Bass Pig for definitive measurement!
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Old June 10th, 2008, 04:39 AM   #5
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Quote:
Originally Posted by Paul Chiu View Post
. since they are spaced so closely together, just how does one know the stereo effect is working?
Paul,
I guess there may be some compromises involved in a mic that is stereo/mono switchable. Please tell me: can you use just one channel input (freeing the other for wireless, for instance), when you switch to mono mode?

Because if you can't, I guess the Edirol CS-50 is a much better solution; it is not advertised as stereo/mono switchable, but in the Wide stereo the separation is absolutely fantastic, while in the Focus mode it's very directional indeed - so much so that I can disconnect one channel (in order to connect wireless, or switch to one of the internal EX1's capsules), and still get true mono sound...
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Last edited by Piotr Wozniacki; June 10th, 2008 at 05:10 AM.
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Old June 10th, 2008, 08:10 AM   #6
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I'd never roll off the frequency response in mic. I'd rather get a better wind screen.

RULE: for professional recording all air conditioners, fans, refrigerators, cell phones OFF as well as fluorescent lights and computers too. I tell that upfront to all clients. The alternative is that I have to fix the audio in post. That will take time and money and may damage the audio.

Quote:
Originally Posted by Paul Chiu View Post
i tried a pink noise generator, but the test was not systemic, i'll need to have someone run it monday....(will report again..)

as for the hum, it may be the air conditioner 8 feet away at the session.

still, do you use the low pass switch option, Craig, on the 680s?
does it roll off below 100hz or more to reduce the wind and other noise?

paul
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Old June 10th, 2008, 08:16 AM   #7
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The mic has surprisingly good stereo spread in stereo. It has excellent side rejection in mono. In mono you only need on channel in. These is a nearly $1000 list mic and it'd be useless for people with that kind of budget for an on camera stereo mic otherwise.

Before making any purchase one should research thoroughly as I did with this mic. I normally wouldn't get a stereo mic because IMHO most are "compromised" but this was a rare find and apparently only recently introduced by Sony.

Quote:
Originally Posted by Piotr Wozniacki View Post
Paul,
I guess there may be some compromises involved in a mic that is stereo/mono switchable. Please tell me: can you use just one channel input (freeing the other for wireless, for instance), when you switch to mono mode?

Because if you can't, I guess the Edirol CS-50 is a much better solution; it is not advertised as stereo/mono switchable, but in the Wide stereo the separation is absolutely fantastic, while in the Focus mode it's very directional indeed - so much so that I can disconnect one channel (in order to connect wireless, or switch to one of the internal EX1's capsules), and still get true mono sound...
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Old June 10th, 2008, 08:18 AM   #8
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Originally Posted by Craig Seeman View Post
I'd never roll off the frequency response in mic. I'd rather get a better wind screen.

RULE: for professional recording all air conditioners, fans, refrigerators, cell phones OFF as well as fluorescent lights and computers too. I tell that upfront to all clients. The alternative is that I have to fix the audio in post. That will take time and money and may damage the audio.
Very true, Craig.

Only... not always viable. I recorded a music performance lately, and even though we asked the audience to please turn off their mobiles, not everyone did. Result: audio spoiled by roaming connections coming into some audience members' pockets...
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Old June 10th, 2008, 08:32 AM   #9
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As long as the client knows the consequences. I make it quite clear what can go wrong and the client must be informed in advance and either consent to my control or the results due to the lack of such.

I've shot many music performances and some it horrible conditions. The first thing I bring up in my client conversation is the audio.

Quote:
Originally Posted by Piotr Wozniacki View Post
Very true, Craig.

Only... not always viable. I recorded a music performance lately, and even though we asked the audience to please turn off their mobiles, not everyone did. Result: audio spoiled by roaming connections coming into some audience members' pockets...
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Old June 10th, 2008, 08:40 AM   #10
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As long as the client knows the consequences. I make it quite clear what can go wrong and the client must be informed in advance and either consent to my control or the results due to the lack of such.

I've shot many music performances and some it horrible conditions. The first thing I bring up in my client conversation is the audio.
Sure thing, with the exception that the audience is NOT the client, so they don't care. Recently I started asking them to switch their mobiles completely, not just mute them; they give me that strange look "what is this guy thinking! I don't even remember my PIN code, so I couldn't switch mine back on again" :)
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Old June 10th, 2008, 08:41 AM   #11
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A/C off will be a hard option in the summer

Craig,

any options to turning off the A/C, other than wireless lav mikes on each player?

is there some really directional stereo shotguns that pick up only what's straight ahead?

actually, that's rather dumb, as the A/C noise is all over...
oh well, any options?

paul
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Old June 10th, 2008, 08:56 AM   #12
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Client must either give me control or take responsibility or consequences.
I also tell people to turn them off, not mute or vibrate. Try putting a mute cell phone next to various unshielded speakers and you'll hear the results. They're still transmitting unless they're off.

When the audience doesn't care, the client must live with the results. This is all part of the discussion with client.

You need to offer the client the options (and cost). Direct recording from mixing board for example or Camera mics with all the risks laid bare to them.

Quote:
Originally Posted by Piotr Wozniacki View Post
Sure thing, with the exception that the audience is NOT the client, so they don't care. Recently I started asking them to switch their mobiles completely, not just mute them; they give me that strange look "what is this guy thinking! I don't even remember my PIN code, so I couldn't switch mine back on again" :)
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Old June 10th, 2008, 09:03 AM   #13
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tried any other stereo mikes with EX1?

Craig,

i tried the big fussy rycote furry and it was so big i am afraid the wide angle will pick it up.

a few colleagues have mentioned that perhaps the mike's "inherent noise" may be higher than other top end mikes.
i am not sure that is as the sony ecm-680s is higher numbered than the ecm678 which has a posted 16db for inherent noise. the ecm680s post no such stat so i don't know.

did you try any other high end shotgun, mono or stereo that has real low listed inherent noise stats? most of these like the sanken cms-10 or senny mkh-418s are way more money than our sony ecm680s. are these better at handling noise?

thanks

paul






Quote:
Originally Posted by Craig Seeman View Post
I'd never roll off the frequency response in mic. I'd rather get a better wind screen.

RULE: for professional recording all air conditioners, fans, refrigerators, cell phones OFF as well as fluorescent lights and computers too. I tell that upfront to all clients. The alternative is that I have to fix the audio in post. That will take time and money and may damage the audio.
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Old June 10th, 2008, 09:24 AM   #14
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Paul,

You should be able to very easy distinguish between the mic inherent noise, and anything else. Please do not overlook your cables; search this forum for Bob Grant's post about the XLR "pin one problem".
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Old June 10th, 2008, 09:32 AM   #15
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You're not going to be able to roll off "inherent" noise nor would such noise necessarily be below 100Hz. The camera pre amp and internal electronics may have more inherent noise than the mic itself. Also one needs to get a handle on the mic input sensitivity controls.

There are short haired Rycotes worth looking at.

If you look at my Brooklyn Bridge Fireworks video on Vimeo (see EX1 clips section) you'll see that Bass Pig and I had a discussion about the camera and the ECM680s. He's tested the camera already but I suggested he also test ECM680s.

Vimeo is not a good way to judge many of the audio characteristics since the video goes through a round of audio compression before uploading and then Vimeo compresses it again. Often times compression software does "normalization" as well as some equivalent of limiter and/or AGC type controls.

Note that Bass Pig thought I should bring down the input sensitivity even further than I did and I thought I was being very aggressive.
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