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633&664 am I missing something ?


nicoproson

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Hello,

I own a 633 and often use a 664. I don't really get why phase inversion is avaliable only on channel 2 on 633s and 2&4 on 664s...

I have my boom on channel 1 and the rest is all lavs which I guess is standard set up. I often have phase issues whith my lavs and I can only flip channel 2...

What's the logic behind sound devices choice ? Do you have any advices for me ?

Thank you

Nicolas

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+1 Same here! 

 

My very first gig that I used my 633 on was for a show and had program material bleeding from mics obviously and the first thing I looked after was phase flip. I was SHOCKED when I realized that this basic function (for a high-end mixer/recorder) is not on all channels! 

 

Today I'm at a gig which I could totally use my 633 for but guess what, had to bring my 788 cart which is an overkill but I didn't want to take the risk!

 

Phase limitation on 633 (and looks like 664 as well) is odd to me as I would think it is a software manageable function. Well... let me stop here before making more unrealistic assumptions because clearly it is not a simple software tweak and SD somehow couldn't do it.

 

Engin

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Hello,

I own a 633 and often use a 664. I don't really get why phase inversion is avaliable only on channel 2 on 633s and 2&4 on 664s...

I have my boom on channel 1 and the rest is all lavs which I guess is standard set up. I often have phase issues whith my lavs and I can only flip channel 2...

What's the logic behind sound devices choice ? Do you have any advices for me ?

Thank you

Nicolas

 

Nicolas,
 
It seems to me that you are confusing polarity and phase.
- Polarity is inverting the audio signal : usefull for  stereo mics  in case one is wired in the wrong side (+is - or the opposite).
- Phase means a delay between two mics, it can't be correctly solved by the polarity switch (too many people are calling it phase switch). It can be corrected by a delay between those two mics. You can do it in post or in production (if the delay is unvariable). The delay menu exists in both 633 and 664. (You can also avoid phase issues by using only one mic on one audio source !)
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Nicolas,

It seems to me that you are confusing polarity and phase.

- Polarity is inverting the audio signal : usefull for stereo mics in case one is wired in the wrong side (+is - or the opposite).

- Phase means a delay between two mics, it can't be correctly solved by the polarity switch (too many people are calling it phase switch). It can be corrected by a delay between those two mics. You can do it in post or in production (if the delay is unvariable). The delay menu exists in both 633 and 664. (You can also avoid phase issues by using only one mic on one audio source !)

Indeed I meant polarity.

I sometime mix my own audio and I have to invert the polarity of my lavs on order to have a full sound.

So yes I can fix it in post but voices are often sounding very thin in my mixdown....

Sound devices please make an update with polarity switches on all channels. It would be a uge improvment.

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i don't know a lot about these things and i might be missing something, but couldn't you just wire up some polarity reversing patch cables (or even better, an direct connection cables with different polarity) and use those if necessary? not quite as convenient as a switch but a low cost solution for your existing gear.

also i'm wondering why you would have sometimes polarity issues and sometimes not, i would assume that the polarity doesn't suddenly change somehow - do you often have to use untested radios/lavs?

chris 

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Generally what people do as far as I know is to test all the microphones you are going to be using together for the same polarity (often referred to as phase, even the provided switches are called phase reversers). I will add that it is not entirely incorrect to refer to polarity as a phase issue, but that's another discussion. With my setup, I discovered while testing that DPA lavs into my transmitters are "out of phase (polarity)" with Sanken COS-11 lavs into identical transmitters. So, if I am using DPAs and COS-11s in the same scene, I flip the "phase" polarity switch on the input for the COS-11s. The reason for switching the COS-11s is that the DPAs are all correct with respect to all of my other conventional (non-lav) microphones.

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also i'm wondering why you would have sometimes polarity issues and sometimes not, i would assume that the polarity doesn't suddenly change somehow - do you often have to use untested radios/lavs?

chris

Indeed it's not a random phenomenon. I have this issue on track where I can't " switch phase"

I have this issue with my personnal Sennheisers G3 with cos11...

Is there a wiring solution ? Can I modify my XLR/JACK câble or can I create some kind of polarity inverter câble ?

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Yes, you can. There are commercially available XLR barrels that flip pins 2 and 3. Or it's a simple matter to build (or have built for you) short jumper cables which do the same thing.

 

that's what i thought, but since i'm way out of my comfort zone here it's good to have confirmation from somebody in the know... so i guess that means you could also wire a direct jack-XLR cable with proper polarity, or have somebody do it for you.

 

chris

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that's what i thought, but since i'm way out of my comfort zone here it's good to have confirmation from somebody in the know... so i guess that means you could also wire a direct jack-XLR cable with proper polarity, or have somebody do it for you.

chris

You say your way out of your comfort zone here, how have you cone to the conclusion you need the phase flipped?

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You say your way out of your comfort zone here, how have you cone to the conclusion you need the phase flipped?

 

i don't.

 

i just was responding to the original poster that this might be possible with a simple cable and hoped somebody would confirm ;)

 

chris

 

 

ps: which brings up a good point:

what is a good indicator that one has a phase/polarity problem?

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i don't.

i just was responding to the original poster that this might be possible with a simple cable and hoped somebody would confirm ;)

chris

ps: which brings up a good point:

what is a good indicator that one has a phase/polarity problem?

Sorry, I think I misunderstood your post.

Jeff summed up pretty well in his post when it's commonly needed.

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Here is the simple test: plug 2 microphones into your mixer's inputs (this could be a hardwired mic or the output of a wireless receiver) and assign to a common mix bus;  then hold the 2 mics close together and hum into them (low frequency tone from you or you could use an audible tone generator if you have one to play a tone or pink noise through a speaker). Now, bring up input 1 to a decent listening level, then bring up input 2 and at a certain point the overall level will increase if the mics have the same polarity (in other words, the signals will be additive). If, as you bring up input 2 the overall levels actually decrease, sometimes even to the point of canceling each other out, this is the indication that the two do not have the same polarity. If this is the case, flipping the polarity or phase invert switch on one of the inputs should now cause the levels to increase rather than decrease.

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Nicolas,
 
It seems to me that you are confusing polarity and phase.
- Polarity is inverting the audio signal : usefull for  stereo mics  in case one is wired in the wrong side (+is - or the opposite).
- Phase means a delay between two mics, it can't be correctly solved by the polarity switch (too many people are calling it phase switch). It can be corrected by a delay between those two mics. You can do it in post or in production (if the delay is unvariable). The delay menu exists in both 633 and 664. (You can also avoid phase issues by using only one mic on one audio source !)

 

 

Are you sure?  I thought "input" delay was only available on the 633.

 

Tom

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i don't.

 

i just was responding to the original poster that this might be possible with a simple cable and hoped somebody would confirm ;)

 

chris

 

 

ps: which brings up a good point:

what is a good indicator that one has a phase/polarity problem?

 

In my case it's pretty clear, I have a loss of low end when the phase switch is off. And it's pretty easy to compare since there is no phase switch on the other channels... By the way let me clarify that my phase issues were not happening between lavs but between my lavs and my boom. 

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Jeff's #9 post in this thread says it all.

As has been discussed before the Sanken COS 11 when wired as 2 wire (as is the case for many transmitters) is

reversed polarity to most other mics - booms or lavs. That is why I reverse the polarity on all my 400 series

receivers when using Sanken COS11s. It is a permanent situation - doesn't change in different situations. So,

whether by switching or adapting at your receiver outputs, the polarity should be correct. Your can hear the

difference.

Regards,

Jim Rillie

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I am embarrassed by the fact that when I switched my COS-11s to "servo" wiring, I didn't know right away that they were reversed. I "corrected" the issue, as it occurred, by flipping the switch, but didn't realize it should be a permanent setting for any time my COS-11s are in use.

It's now my SOP to reverse "phase" on venue for channels using COS-11.

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that's what i thought, but since i'm way out of my comfort zone here it's good to have confirmation from somebody in the know... so i guess that means you could also wire a direct jack-XLR cable with proper polarity, or have somebody do it for you.

 

chris

I don't know what's available where you are, but here in the US, barrel polarity reversers are easily available at a reasonable price. The Hosa barrel pictured below lists for US $12 and is available for ~US $7. 

Best regards,

Jim

post-1223-0-16679600-1424711906_thumb.jp

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