tapping into house PA

[David W. Jones]

Robert, you don't want to use a direct box as a go-between from the mixer to your camera.
A direct box is a musical instrument interface, for converting an electric bass guitar signal for example, to a balanced signal into a mixer.

Bill Davis has given you a very good list of what you should have in your bag.

Good Luck!

Dave

[Rick Reineke]

David is certainly correct, you do not absolutely need a DI... however if I where anticipating patching into an unknown system, I wouldn't leave home without one. ( and for that matter an IL19 iso, but that's another story)
Which DI Robert? Surprisingly, the cheaper Live Wire Solutions SPDI DI model has an attenuator and would most likely be better for A/V production. The more expensive model appears to be of heaver duty build and shielding, but with no attenuation.
IMO, the Rolls DB25b is an even better option with a variable attenuator, and is a little cheaper. All three have ground lift switches, which is a 'must have' feature, and standard on most DIs.
NOTE: If buying a DI for musical instrument purposes, I would recommend an active DI, like the Countryman Type 10, a long-time favorite among pro players and engineers.

[Rick Reineke]

Message deleted again, sorry. PC issue, NOT GOOD

[Robert Bobson]

I had spoken with the location AV guy last week, and he told me No Problem, they'd be able to hook me up - any type of connection I need.

Well, the event was yesterday, and the AV guy didn't show up till the last minute... and then said he was too busy to hook me up to the house board.

So I ran a wired mic to the podium for that part of the presentation. As for the rest of the house mics, luckily the AV guy was able to record his house feed on CDs, which he gave me afterwards.

Now, if I can just sync them up with the video, I should be okay.

It doesn't matter how much you plan, there's always something...

Thanks again for all your suggestions!

[Jay Massengill]

Another good problem solver to have in your kit is the Ebtech Hum Eliminator. It isolates from ground loop hums and converts to or from balanced to unbalanced in either direction. It doesn't change the signal level like a DI is designed to do, and is primarily for line-level to line-level connections.

And yes, there is always something unexpected that is likely to happen. If you have a couple of alternate plans in place, always including your own independent equipment, you can usually deal with a problem and get a satisfactory end product.

[Bill Davis]

A "direct box" has almost no use in a video production chain.

It's function is to bypass the "amplifier stage" that is typical in a live music performance where guitar or other instrument is plugged directly an amp. A microphone is then placed in front of the amp - and that mic level signal is sent to the mixing board.

A "direct box" bypasses the mic/amplifier and simply feeds a musical instrument "directly" into the input of the mixing board matching impedance and level so that the instrument signal "looks" like a mic to the board input.

All audio for video is concerned with the OUTPUT of the mixing board - and routing it properly to the input of a recording device.

No "direct box" needed.

[Richard Crowley]

Of course Mr. Davis is correct that a Direct Box is NOT the right tool here. However sometimes that is all we have in the role of "isolation". A proper isolation transformer (such as the Ebtech mentioned by Mr. Massengill) would be the correct solution.

A direct box is better than nothing when you need some isolation from an unbalanced source into a mic-level input on your camcorder, etc. In exactly the same way you can hammer a (small) nail with a wrench.

[Benjamin Maas]

Bill Davis's list is pretty much spot on... When I'm mixing shows and a video person show up and has even half of the gear he has listed, I'm happy to help out. When a video person shows up at the last minute, doesn't have any cable or connectors to interface *their* camera, I tend to not want to help.

I would usually suggest a couple small changes to what he listed-

1. XLR cables longer than 25' are a good idea. 25' can be consumed easily just moving around a console.
2. Consider a 2 pair cable/snake. When I'm shooting, I'll bring a 2 pair snake with me to make it easier to run audio. I have several of these- a couple are standard snakes with 2 full lines in them. A couple are what I usually refer to as duplex cables. Take a piece of star quad cable (4 conductors plus a ground) and have it terminate in a 5 pin XLR. From there, you adapt out from the 5 pin to a "Y" with 2 standard 3pin XLRs. Ground is shared between the two lines. I've run over 100" with this cable without issue and the advantage is that it is a single thin cable so it is easy to route, tack up over doors, etc...
3. If ground issues are a concern- especially if a lower end console is used that doesn't have balanced outs, get a pair of these: LINE BALANCER/SPLITTER - Catalog - Whirlwind You can get multiple functions out of it- split to multiple cameras/locations, balance a line, ground lift, hum removal, etc...

I've used DI's plenty of times to do a similar job, but it really isn't quite the right tool. If you do use a DI, use passives, not active DI boxes. Be aware that your input level will almost certainly go down from Line to Mic. Also, listen to your signal- if you are hearing distortion, make sure the buffer on the DI is engaged. You may be overloading the DI.

--Ben

[Ron Edwards]

Told ya about house sound ... "Don't do it"

Now your worried about sync with the audio C/D ... I would be too !

Wow...why didn't you send a wireless lav signal directly into your cam?

SIMPLE AND YOU CAN MONITOR THE SOUND ON THE FLY

[Robert Bobson]

Happy ending - the CD audio sync'd up fine and the project was a success.

A wireless would have been nice, although I've run into problems with wireless interference.

I'm looking at a digital audio recorder that I can feed wired mics into!

[Cole McDonald]

I've used a VHF wireless system to hook into a headphone monitor jack on the mixer (friendly with the mixey folks)... Stereo > Mono adaptor into my wireless setup. This allowed me to capture synch sound throughout my gig... I even got to set the levels on the headphone out to hit my meters right :)

[Shaun Roemich]

Originally Posted by Cole McDonald

I've used a VHF wireless system to hook into a headphone monitor jack on the mixer (friendly with the mixey folks)...

Scary thing about doing that though is if the sound guy solos a channel at any point, that's all you get on your feed.

I've done it (and it's a good reminder) but I'd suggest that is a LAST resort and would only consider it as a backup to another source that is "guaranteed"... like a room mic.

[Rick Reineke]

Yes, most systems with an operator would need the headphone freed up for soloing or other purposes. with a set and forget system in hotel meeting rooms and such, I suppose that would be ok, but in either case I would opt for a main or sub feed, or better yet, a prefader aux send, which the least likely to be fiddled with.

[William Hohauser]

Having just tapped into a theatrical house PA (it was offered by the house) I have a few bits of something to add.

1) Expect large houses to have some sort of feedback preventing delay in the audio. Usually one frame or so. The reverb will be apparent when you play back your video with a camera or room mike mixed in.

2) The PA mix is for the house not television so don't expect everything on stage to be in the house feed in anything approaching a usable mix. I did camera on a concert once and the house audio tech offered to so a multitrack recording of the band but forgot to assign the tracks before it started. We ended up with with eight identical house PA tracks which were minus the drums and the bass (which had it's own stage amp). The room mikes were not good enough and the project never went into edit. The theater pice we just filmed had a couple of singers who could fill the room without amplification so the tech turned them down on the house PA. Fortunately the room mikes were able to get them with decent quality and I could mix it into the edit.

3) I find that a portable mixer is the best solution as it gives me the most ability to adjust the house feed although an audio kit is the better in situations where a mixer is too much to deal with.

[Paul R Johnson]

One has a double wound transformer, so the ground lift leaves the earth intact, but provides insulation between incoming and outgoing grounds. The other is the more usual type that simply lifts the ground, relying on the ground the other end. I'd be happy with both.

A DI box is pretty useful, because if you want a mic level signal from the board, then how else will you get it from line level sources?

Quality wise, a direct board feed is better - when mixed with the room sound.

The frame or so delay in digital boards is a necessary function of analogue to digital coding and decoding - it does have a small benefit in feedback reduction. The only other delays are usually provided externally in the speaker management systems, not in the mixer - so what you get from the board is as close to aligned as is available. The distance from the stage to the cameras usually matches or is worse than the latency of the mixer, even digital ones.

NEVER trust the board op to keep your feed balanced. They won't have the time or inclination to do it. At best you will get a mostly balanced feed - but it won't be perfect.