tapping into house PA

[Robert Bobson]

I've read the postings on this but have a few more questions.

I'm recording an event this weekend that will have 5 people at microphones, and the theater has a house PA system. But I haven't been able to speak with the A/V person, and don't know what kind of board they have, etc.

So essentially I'll be winging it. And I'm not exactly clear on everything that's involved.

I want to attach a feed from their board to a spare video camera in the audio booth to record the audio. I'll then be free to move about with the main camera.

The camera has both XLR and RCA inputs.

I'm going to buy a Passive Direct Box. These allow signals to flow both ways, yes? I've read that they can be used to connect low signal guitars to the high signal boards. But they'll also connect the output of high signal boards to my low signal camera, correct?

I also understand that they have several types of connections; XLR, RCA...so I'll take along an assortment of cables and male/female adapters...

I'm also worried that their XLR may be wired differently than my XLR, but I'm not sure how to test that? and can hooking up a differently configured XLR damage anything...their board or my camera? are there some type of "crossover" adapters available?

Should I get some XLR to RCA adapters? RCA to 1/4"???

any other tips for "going in blind"???

thanks :O

[Gerry Gallegos]

any and all adapters you can add to your kit will help you adapt, however you need to make sure you attach only adapters that will not compromise the original signal.

A direct box even a passive one is not made to convert to +4 balanced line level but is designed convert a instrument level or line level ( -15 to -10 roughly) to microphone level which traditionally sits at about -30db they are NOT designed to bring XLR +4db line level down to -10 consumer line level.

what you ideally need is what is called a splitter preferably an isolated splitter as the sound guy will not likely let you interrupt his main feed with anything that could compromise what he is doing.

but having all these things in your kit will keep you prepared for more situations as they pop up.

more than likely the sound guy will have an available feed that he can probably give you if you coordinate with him or her. this is where your people skills come into play. but be prepared to adapt whatever his board may have to your camera (this is where a DI would work great if he only has line out -10 consumer, this can give you an isolated mic level feed to your camera) or you can simply adapt it to RCA that you say your camera has.

good luck, hope this helps a little

GG

[Robert Bobson]

"be prepared to adapt whatever his board may have to your camera (this is where a DI would work great if he only has line out -10 consumer, this can give you an isolated mic level feed to your camera) or you can simply adapt it to RCA that you say your camera has."

So if the AV tech says "I have this output for you to attach to", how do I know what level it is? or what level I need?

Do I always need to connect to the board through a transformer-type DI to keep the electrical systems separate?

I don't mind using the RCA connection. Would most (?) boards have an "RCA out" that would be the correct level? or do I need an RCA inline attenuator ???

I'm going to set a third camera up with a shotgun mike pointed at a house speaker - just in case nothing else works.

thanks for your reply

[Steve House]

Why record to a spare video camera? A purpose built audio recorder should do a much better job. The audio sections of video recorders typically leave much to be desired in the quality department.. If that's all you have then go for it, of course, but you might want to consider adding a dedicated audio recorder to your kit at some point.

[Rick Reineke]

Aside from the other good recommendations above.

"So if the AV tech says "I have this output for you to attach to", how do I know what level it is? or what level I need?"
> 1/4" TRS outputs will likely be of the +4dB level. Your best option in that case is to have a 1/4" to XLR adapters or cables, and set your camera to 'Line'. Using a balanced line level signal can offer very long cable runs without issue. NOTE: (although the output is referenced to +4dB, the actual output may be lower depending on how the mixer is gain staged.) If you experience a ground-loop hum, use your DI.. most DI boxes have a 'ground lift' switch for those instances. An RCA connection is normally referenced to unbalanced -10dB, in that case, the cable going to your DI should be short and set camera or other recording device to 'mic' level when inputting from the DI.

"Do I always need to connect to the board through a transformer-type DI to keep the electrical systems separate?"
> Not always.. refer to above.
FYI: It's usually best to power the recording device from the same A/C circuit as the house PA, avoiding ground-loop issues in the first place.

"I'm also worried that their XLR may be wired differently than my XLR, but I'm not sure how to test that? and can hooking up a differently configured XLR damage anything...their board or my camera? are there some type of "crossover" adapters available?"
> Most XLR's are wired the same these days ( once upon a time there was a discrepancy on some equipment as to which pin.. 2 or 3 was the hot = +. Pin-2= hot, has been the standard for quite a few years now so you needn't be too concerned if your XLR cables are wired the same. You do have a some way to test your cables... (Pin-1 to Pin-1.. (ground/ cable shield) -- Pin-2 to Pin-2 --- Pin-3 to Pin 3.
NOTE: Even if Pins-2-3 were reversed, it would cause no damage.
FYI; 1/4" TRS > XLR cable or adapter should be wired to use the following pin allocation:
- XLR pin 1 - to 1/4" TRS Sleeve (ground/ cable shield)
- XLR pin 2 - to 1/4" TRS Tip
- XLR pin 3- to 1/4" TRS Ring

[Bill Davis]

Robert,

Let me try to make this simpler.

To start off, you should never presume to touch or otherwise jack into house sound equipment yourself. That’s the job of the FOH (front of house) mixer. His or her job is to route the board signals to the appropriate ports and set them up for you.

Next, there are 3 basic connector types that show up most on common sound boards. XLR connectors, 1/4" phone connectors, and RCA-style line-level connectors.

Deciding which to feed to you is the board operators option. You can “request” what you want — but some or all of the available choices may already be in use for other purposes so the reality is that we video folks have to take what we can get.

So the smart videographer who wants a clean board feed comes prepared with all the necessary “problem solvers” in hand.

Here’s what I traditionally carried to gigs where a board feed was likely.

(ITEM 1.)
A pair of quality 25’ XLR mic cables.
These are commonly terminated in an XLR-M (male) connector at one end and an XLR-F (female) connector at the other. With these two basic cables you can set up your camera up to 25’ from the board and take a feed to two camera inputs.

ITEM 2.
A pair of 12” to 24” ¼” stereo Male to XLR-Female patch cords.
These turn one end of each mic cable into a ¼” phone plug which is what most “music oriented” mixing boards like to see. This lets the board operator give you a feed from various common patch points including AUX outs, AUX sends, and even Channel Inserts if necessary. If you’re working with an experienced board operator, request these as “pre fade” sends so that gain adjustments at the mixer don’t effect your feed. These should be "balanced" adapters with at least 3 separate connection pins or rings at the plug ends. Two segment plugs do NOT allow for a balanced feed, but a 3 conductor plug works just fine with a 2 conductor unbalanced signal.

ITEM 3.
A pair of switchable XLR Barrel Pads
These will reduce a line level feed down to mic level. The best ones are switchable with various stages of perhaps, 10db, 15db , and 25db or similar. This lets you take a line level feed, and pad it down to a signal that won’t overdrive a mic input at the camera. (If you have a MIC feed, but your camera requires a LINE level, you’ll need signal amplification and that typically means you need to add a powered mixer to your setup.)

ITEM 4.
A quality, well-shielded 10-20 foot (or so) RCA stereo patch cable. If all the sound board operator has available is a “tape out” send, this will let you tap into it and use the RCA Female to XLR-M adaptors below to feed it to your camera inputs.

ITEM 5.
A pair of RCA-F to XLR-M adapters. This lets you direct-connect the RCA cable to the camera’s mic inputs (using the pads if necessary, some cameras may have direct RCA audio inputs to the tape, but many do not.)

Occasionally useful but less "necessary" are:

ITEM 6.
A pair of XLR “Y” cables. (each one an XLR-M to two XLR-M’s which will transform a mono board output into TWO feeds one for the original house feed and one for your camera – but most sound engineers don’t like folks putting an extra load on their “main outs”, so this may just gather dust in your kit. I think I used mine maybe twice in 15 years of my prime working life - most commonly in places like high school GYMs where nobody’s really in charge and you can get away with it.

ITEM 7.
The final “useful” item would be a couple pairs of XLR “gender changers” which are nice when the house guy drops you a line and you’re expecting it to be terminated in one gender, but it actually ends in the other gender instead. (trust me, it happens more often than you think!)

If you have this equipment in your kit, along with a camera that lets you adjust the microphone levels properly, you should be good to go in most “house feed” circumstances.

This is not a “comprehensive” list – just a good basic start on a problem solving “tap the house board” sound kit.

Hope this helps.

Good luck.

[Jon Fairhurst]

Bill, you get the "nailed it" post award for the month. With those tools, a recordist can take anything off a board. The only way you could fail is if there are no free outputs, or if the mixer tells you to get lost.

Control everything you can control. And dont sweat the stuff you cant

[Steve House]

Originally Posted by Jon Fairhurst

Bill, you get the "nailed it" post award for the month. With those tools, a recordist can take anything off a board. The only way you could fail is if there are no free outputs, or if the mixer tells you to get lost. ...

And it should be noted by our OP that the latter eventuality is always possible and he should plan for a backup strategy accordingly. The FOH mixer is there to provide house sound for the audience and anything he provides to the videographer is done purely as a courtesy. He is perfectly within his rights to tell the videographer to eff off. So come prepared to record without receiving a house feed at all, treat him nice and offer to buy him a beer after the show.

[Robert Bobson]

Thanks again for all the great advice!

[Jay Massengill]

The only thing I would change in Bill's post is Item #2 would be more useful in the OP's case if they have male XLR ends. That way it would be the proper gender for being a 1/4-inch output cable from the board to an XLR input on a camera or recorder.

[Bill Davis]

Hey, it was a long post.

If that's the biggest case of "gender confusion" I have in my life, I'm OK with it. ; )

(Also, now you can see why I recommend carrying both F/F and M/M XLR "gender changers" with you - sometimes what you think you're thinking isn't what you think to ask for in the heat of setup!)

Peace.

[Robert Bobson]

can someone explain what the difference is between these two "direct boxes"? If I wanted my camera's XLR fed by a 1/4" feed from an audio board?

GuitarCenter

thanks

[Ron Edwards]

My suggestion for house sound "DON'T DO IT"

The only two times I would have been burnt is taking a feed off the "sound guy". If it hadn't been for my backup I'd been in big trouble.

I found the best way is to ask the "sound guy" where a "sweet spot" might be that you can set up a wireless lav and feed the signal directly into your cam. I have dropped lav mics down from the balcony very near the sound guy and got great sound.

I would also recommend a totally separate sound recording (backup).

[Rick Reineke]

Originally Posted by Robert Bobson

can someone explain what the difference is between these two "direct boxes"? If I wanted my camera's XLR fed by a 1/4" feed from an audio board?

GuitarCenter

thanks

these two "direct boxes"... What two "direct boxes?
GC page: "Compare Another Item"

[Robert Bobson]

Sorry - guess that page went away. the two direct boxes are:

Live Wire Solutions SPDI Passive Direct Box with Attenuation Pad and more Direct Boxes at GuitarCenter.com.

Live Wire Solutions PDI Double Shielded Heavy Duty Passive Direct Box and more Direct Boxes at GuitarCenter.com.

thanks