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Old February 28th, 2014, 08:18 AM   #46
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

Quote:
Originally Posted by Peter Dunphy View Post
It's better to have audio recorded from the mixing desk (both as backup and as a higher quality recorded) into something like the Roland R-88 8-Channel Recorder & Mixer-- which not only records the audio in a higher quality than the SONY HXR-NX3/VG1 camera can manage (is this strictly true?), but also it features a limiter, which will prevent sound passing through it from leaving it in the 'red'.
I don't disagree with anything that Richard wrote. In light of your ORIGINAL question (post #1), concerning the ability to record from boards, I would add that a multitrack recorder gives you flexibility that in-camera recording does not. If you must (or want) to connect a camera to a board feed, you live with the mix from the board. However, when you can lay down several tracks, e.g., 8, you could record (up to) 8 channels (or sub mixes) from the board and then mix to your own taste. Otherwise, you trust the board operator to fade channels and apply any FX that you can live with.

In one instance where my confidence in the operator was almost nil, I just took a few direct outs from the board. In another with more than 30 channels, including instruments, stage mics, and nearly a dozen wireless mics, I relied on the experienced operator to provide me a with a few post-fade mixes through the board's aux sends, all to excellent effect.

In no case do I EVER rely upon my recorder's limiters. Though the limiters are armed, I set levels so that a rare spike is the only thing that might engage the limiters.
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Old February 28th, 2014, 10:11 AM   #47
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

Even a direct output (or pre-fader send) is subject to the board operator skills (or lack thereof). The direct out can still subject to preamp overload and an external comp/limiter wouldn't help. A transformer mic-split would be the 'safest', of course that requires an additional skilled person and more gear. Even then, an awful mix could acoustically would get into the room mics or even the spot mics to an extent.
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Old March 1st, 2014, 01:36 PM   #48
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

I gave this tread some thought and tried to figure out how to simplify it for you. I can’t. The problem lies in your original question about “how do I do it in ALL situations”. That is liking asking me to put everything I have leaned in 20 years in one paragraph, it can’t be done.

What separates a basic camera operator from the guy that gets it right every time is experience and knowledge. The guy that can always get it right is a technician.

Everyday there are a lot of guys out there recording conferences with a couple of cables and maybe a sub mixer (if that) and recording decent audio. Some of them are probably reading this thread and thinking, what are we doing to the poor OP? The basics work in a perfect world. Beyond that, your screwed if you do not understand how to adapt to the real world. Conference audio guts messed up a LOT. Even by AV companies that have their own technicians working on it.

The root of ALL audio is about signal flow. Explaining signal flow is beyond the scope of any simple forum thread. I think you said you picked up Jay Rose’s book on recording good digital audio. That is a great place to start. It will be much easier for us to help you with specific questions instead of broad sweeping ones. Richard did a great job of breaking down your last post, but I suspect you are still scratching your head. There is no easy answer to complex audio situations.

I have learned to THINK of audio in terms of signal flow. You obviously want to learn. Start with the basics, and expand on your foundation from there. The basics of signal flow never change.

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Old March 1st, 2014, 04:37 PM   #49
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

Good comments, Mr. Digges.

Above and beyond getting an appropriate mix, I think the basic concepts to keep in mind are:

1.) the difference between balanced and unbalanced signal wiring, and the different levels typically encountered,

2.) the causes of overload, distortion, clipping, and how to remedy same,

3.) the types and causes of various forms of unwanted electrical noise.

Once a person understands those concepts, then he will know which adapters to use, when and how to use a DI box, etc.

I'm pretty confident that Jay Rose covers those topics in detail, although I haven't looked over his books for a number of years.

One very important point. Once distortion is introduced at some link in the signal chain, you can't remove it at a later link. So the levels must be appropriate at every link (i.e. proper gain staging). And if the distortion is generated inside the house mixing desk (e.g. a mic preamp or a mix buss with gain set too high), there is nothing you can do with your equipment to fix it later. That's why the house equipment and house operator are such an important -- and scary -- variable in the whole equation.

Obviously, as Mr. Digges says, all of this requires more than one paragraph. On the other hand, it doesn't require calculus and it's not rocket science. (I wonder whether rocket scientists have an internet forum somewhere!)
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Old March 4th, 2014, 08:48 AM   #50
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

Thanks so much for the feedback guys.

Here's where I'm at (responses from two sound companies I will be dealing with)

1. A sound technician from one company wrote "All our desks can supply you with audio via a quarter inch jack aux output, it will be unbalanced at line level."

2. A sound technician from another company wrote "Can provide auxiliary XLR out balanced. You would need to have a female XLR at 90% of desk' to get a feed. It would also be worth you having converters (XLR to Jack) and you will also need to convert the female XLR at the camera end to input the camera. Most pro camera's can accommodate XLR but smaller camera's may not, not my game."

My SONY HXR-NX3/VG1 requires a require a male XLR connector to plug into it.

What do you think he means by "female XLR at 90% of desk"?
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Old March 4th, 2014, 09:15 AM   #51
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

"What do you think he means by "female XLR at 90% of desk"
90%? right-angle maybe???.. and it's entirely possible the board has XLR-M outputs. So you need a XLR-F to XLR-M (standard XLR cable)
Most boards these days use 1/4" TRS for outputs.. be it main/masters, aux sends, direct channel, sub-masters and marix, so always have 1/4" TRS to XLR-M cables or adapters. Most are (nominal) +4dB balanced/unbalanced as well, but actual program level can vary depending on if the operator has everything gain staged properly., so expect anything! As was stated, having a DI with switched or variable attenuation is a no brainier when dealing with the unknown..
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Old March 4th, 2014, 09:39 AM   #52
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

90% means ninety percent. 9/10. Universal mathematical notation as in 5th grade math. The other "10%" of boards may have TRS, TS, RCA, or something rare.

90º means ninety degrees. right angle. Universal mathematical notation.

Mr. Reineke's comments about other connectors, adapters, cables, levels, etc. are spot on.
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Old March 4th, 2014, 09:47 AM   #53
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

Quote:
Originally Posted by Greg Miller View Post
90% means ninety percent. 9/10. Universal mathematical notation as in 5th grade math. The other "10%" of boards may have TRS, TS, RCA, or something rare.

90º means ninety degrees. right angle. Universal mathematical notation.

Mr. Reineke's comments about other connectors, adapters, cables, levels, etc. are spot on.
So it's probably a typo that he wrote desk instead of "desks". It was the singular use of desk that threw me.
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Old March 4th, 2014, 10:38 AM   #54
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

Could I check with you guys, when you say "1/4" TRS for outputs" and "My bag of tricks includes some XLR to TRS cables" are you referring to either '1' or '2' on this page?:

A Guide to Types of Cable Connector... | Dawsons Music
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Old March 4th, 2014, 12:47 PM   #55
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

Peter,

"Could I check with you guys, when you say "1/4" TRS for outputs" and "My bag of tricks includes some XLR to TRS cables" are you referring to either '1' or '2' on this page?:" Answer.... number 2 is the 1/4" TRS end of what we refer to, XLR is on the other end.

That page has a good, simple explanation of the jacks.

TRS is Tip, Ring, Sleeve, number 2 on your page

TS is Tip, Sleeve, number 1 on your page

The function of each is explained on that page. But they are only explaining one plug. A 1/4 TRS to XLR patch cable is commonly used to go from the 1/4" output on the board to a XLR input on a camera or other device. If the 1/4" output on the board is balanced you will send a balanced signal to the balanced XLR input.

A TRS to XLR cable cannot carry a stereo signal. TRS to TRS can carry stereo. I only mention that because they do. But here, we are talking primarily about balanced and unbalanced signal paths.

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Old March 4th, 2014, 08:21 PM   #56
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

1) Be prepared for XLR of EITHER gender. Proper outputs from mixing equipment is typically male. However there are situations where they send you the feed via an existing mic drop which is typically female out at the far end (where you are).
2) Be prepared for 1/4-inch both TRS (balanced) or TS (unbalanced).
Those should cover most (but perhaps not 90%) of the cases for professional equipment.
3) Be prepared for RCA and 3.5mm connectors, also. RCA are typically consumer line level (-10dBv), and 3.5mm are typically "headphone level" stereo. But "headphone level" is close enough to line-level to not be a big deal.
4) Be prepared for everything from mic-level up to speaker level.
5) Isolation is always a good thing.
6) Conversion to balanced ASAP is also a good thing.
7) Use conventional balanced XLR cables for the physical link over to your camera (or recorder, or mixer, etc.)
8) Be thoroughly familiar with the operation of your camera (or whatever equipment you are using to receive the audio). Know how to switch (if possible) and the limits for mic level and line level. Know how to turn phantom power on and off. Know how to switch between mic-level input and line-level input.

The Rolls DB-25 (A or B) is a very handy gadget and offers very good performance for what it costs. It pretty well covers these items:
(4) Especialy the Rolls DB25b has a continuously-variable attenuator which accommodates virtually any level you will encounter.
(5) It provides full isolation via a decent transformer.
(6) It balances your feed regardless of whether the source is balanced or not.

A couple of Rolls DB-25 and a handful of input jumper cables and adapters for (1)-(3) will cover virtually all professional situations, and most amateur ones, as well. The DB-25 is inexpensive and very good value for the money. No good excuse not to have at least one or two of them.

The next level up would include a small mixer and some microphones and stands and perhaps mic-splitter transformers as well.

And of course, REGARDLESS of where you sound is coming from, always (Always, ALWAYS) monitor the audio in GOOD, SURROUND, OCCLUDING HEADPHONES. Or GOOD ear-buds (not cheapie things that come with iPod, etc.)

Recording audio without monitoring and metering is exactly like shooting video with framing and focusing. You wouldn't try to shoot video without a viewfinder. You wouldn't expect to record audio without good headphones.
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Old March 5th, 2014, 03:34 AM   #57
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

Terrific advice Steven and Richard (and everyone else who has posted to date). Shall absorb and post again soon.

In the meantime, the 3rd (of 3 -- they don't hire any others apart from these 3)sound technician emailed a reply in response to my email: "Our powered desks would (be able to provide audio via a quarter inch jack aux output, it will be unbalanced at line level) but our digital desks would be XLR.
If we are ever working an event in which you would require an audio feed all you need to do is contact us before hand and we can supply whatever input and run of cable you would require at no extra cost to the client."

So, these are my 3 sound technicians I will be dealing with:

1. A sound technician from one company wrote "All our desks can supply you with audio via a quarter inch jack aux output, it will be unbalanced at line level."

2. A sound technician from another company wrote "Can provide auxiliary XLR out balanced. You would need to have a female XLR at 90% of desk[s] to get a feed. It would also be worth you having converters (XLR to Jack) and you will also need to convert the female XLR at the camera end to input the camera. Most pro camera's can accommodate XLR but smaller camera's may not, not my game."

3. "Our powered desks would (be able to provide audio via a quarter inch jack aux output, it will be unbalanced at line level) but our digital desks would be XLR.
If we are ever working an event in which you would require an audio feed all you need to do is contact us before hand and we can supply whatever input and run of cable you would require at no extra cost to the client."
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Old March 5th, 2014, 04:09 AM   #58
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

If I could focus on this particular sound technician first of all, just to get me up and running, and offer your thoughts if you could:

"All our desks can supply you with audio via a quarter inch jack aux output, it will be unbalanced at line level."

So,my thinking is that because I am taking unbalanced outs from their board, I'm definitely going to need a Rolls-DB25b DI box, to convert the unbalanced signal from the board to balanced, which can then go into the balanced XLR line input on my video camera.

----------

1. I purchase a cable with a ¼” unbalanced Jack ('Stereo Jack'/TRS) Connector on one end [#2 from below link] to plug into the sound desk output, and on the other end of this cable there is a ¼” **TS** unbalanced Jack [#1 from below link] which plugs into the Rolls-DB25b DI box input.

A Guide to Types of Cable Connector... | Dawsons Music

What type of actual cable should I get (cable between the connectors)?

What length of cable is advisable? 3 feet?


2. I purchase an XLR mic cable for balanced signals with a female XLR connection at one end (for the balanced output from the Rolls-DB25b DI box) and a male XLR connection for the camera input.

What length of cable is advisable? 100 feet?

------

How does that sound?

Last edited by Peter Dunphy; March 5th, 2014 at 05:06 AM.
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Old March 5th, 2014, 05:17 AM   #59
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

"1. I purchase a cable with a ¼” Jack ('Stereo Jack'/TRS) Connector on one end [#2 from below link] to plug into the sound desk output, and on the other end of this cable there is a ¼” **TS** Jack [#1 from below link] which plugs into the Rolls-DB25b DI box input."
> The DI's 1/4" input is unbalanced I'd get a cable with 1/4" TS plugs (unbalanced, guitar type) at either end to go from the board's 1/4" output to the DI's 1/4" input. This cable is unbalanced so the length should be kept relatively short. Typically less than ten feet. Shorter is better in this case.
BTW, Not to nitpick but Dawson's terminology in incorrect: A male connector is a "Plug" a female connector is a "Jack" (at least in the pro audio world)

"2. I purchase an XLR mic cable for balanced signals with a female XLR connection at one end (for the balanced output from the Rolls-DB25b DI box) and a male XLR connection for the camera input."
> A standard XLR cable to go from the DI's XLR output to the camera's XLR input. The camera must be set to Mic level BTW

"What length of cable is advisable? 100 feet?"
> Depends how far you will be from the DI. Most have many of different lengths. However since it's balanced coming out of the DI, length is not an issue. You could likely run 300+ feet without any audible issues. I would recommend purchasing good quality cables.. Not only are the less likely to pick up extraneous RF noise, they much easier to work with and coil up. A good quality cable should last your entire career. w/o catastrophic accidents.
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Old March 5th, 2014, 10:07 AM   #60
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Re: What's your kit-list to attach various sound desks to your cam's XLR input?

Richard, Your last post has to qualify for some kind of record about how much good information can be fit into one post. Great stuff!

Peter, A couple more basic tips:

Tech areas, ie: the table where the desk is, are notorious for having big piles of messy cable all over the place. Make sure your audio cables are not run alongside AC power cables. You should avoid contact with power cables at all times. If they must touch, do it at 90 degree angles.

Depending on how much gear is at a tech area, it is also common for their to be a 3 phase 60 amp electrical drop box nearby. Technicians often throw a piece of black drape over it because they are ugly. Keep your audio cables away from it too. One time, we had one leaning against a back wall next to a tech station covered by a black screen skirt. I looked over and saw a guest sit on it, and he set a large cup of coffee down next to him on top of it. After I caught my breath, I politely removed him. I did not know how to explain, if he spilled his coffee his gonads were going to be welded to a metal box by the electrical arc.

Using an aux send is a good feed. Remember that the gain must be set for every channel that is in use. If the audio guy forgets to turn up the gain on a channel, like PC audio for example, you will not receive audio from that channel. A totally unacceptable but common fail! If every channel is tested and gain levels are set this does not happen. So what does the fail tell you?

Steve

Edit: I should note that now if a drop box is placed outside of our tech area they are clearly labeled as HAZARDOUS. Not only would the coffee spill have been catastrophic.....I HATE it when my show goes black!
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