Headphone audio
 

Many times when I film a dance recital or theater performance and need a board feed I have to as a last resort plug into the sound board’s headphone jack. I would rather have a mono feed from aux xlr out often a teenager who’s only there to operate it has no knowledge to give me a proper feed or sometimes the board doesn’t have enough outs and yes I always request a feed in advance but inevitably you get there and you are struggling to get audio.

So the question is, is there anything wrong getting audio from the headphone jack? The other question is what’s the best 1/4 to xlr adapter (mono vs stereo) and how it effects the feed. I’ve had some board operators tell me only use a stereo 1/4 as opposed to a mono. I assume no matter what adapter ( stereo or mono 1/4 to xlr) into a headphone jack isn’t going to sum a stereo feed but rather discard one of the channels? This will travel through an xlr cable into one of the camera’s channels.

Re: Headphone audio
 

Option 1: For mic level XLR input. Purchase a DI (Direct input) box (for instance the low cost Rolls DB-25(b) has two 1/4" inputs and a single XLR mic level out. it also has switchable or variable attenuation) There are other DIs available that have RCA and/or 1/8" inputs.. You may need a standard off-the-shelf adapter cable though for a 1/4" headphone output.

Option 2: For line level input. Build or have someone build a custom 1/4" TRS to XLR cable/adapter. Wired as such: 1/8 or 1/4 inch TRS, Tip and Ring connected to XLR pin-2, Shield/ ground to XLR pins-1 and 3.
BE AWARE: a standard off-the-shelf 1/4" TRS to XLR adapter would result in no audio at all... the Left/Right <> Hot /Cold configuration would be 180 degrees out-of-phase on a XLR input .

Re: Headphone audio
 

You could us a passive line mixer (e.g. Behringer Micromix MX400) to combine the stereo output of the headphone jack to mono. Use a TRS to dual TS "insert" cable to connect them.

Re: Headphone audio
 

Except then you're connecting two amplifier outputs together without isolation. I would not recommend this. The two 1/4" jacks are not two inputs, they are parallel so you can patch through the device using one as an input and one as an output.

Re: Headphone audio
 

There are several caveats to this method. Not to say that I haven't resorted to using it myself on occasion.

Using the headphone output means that the operator can't use the headphones (as for cue, preview, etc.) and is subject to the operator leaving the controls fixed (which bus is monitored, headphone level, etc.). That is rather dodgy IME and only an option low on my list.

Taking only one channel (Left or Right) and discarding the other is OK if they are running the system completely in monaural. But, of course if they are playing the tracks in stereo, then you are getting only 1/2 the music and likely to sound strange.

I love the Rolls DB25 iso box. I have several of them myself and always keep at least 2 or 3 in my remote kit. But @Patrick Tracy is correct that the two 1/4 inch TS jacks are connected in parallel to allow "looping". Connecting the Left and Right output from anything hard-wired together is rather an abuse and frowned upon. Although it is unlikely to actually damage the gear and only somewhat likely to damage the audio signal either. I admit to violating this rule on more than one occasion. But it is not "proper".

But the iso box is a great tool to isolate you from the venue system (with the transformer), and trim the level to something comfortable to your gear, AND to convert to balanced, low-impedance so that you can run the signal a long distance where necessary. I highly recommend the Rolls DB25

And note carefully @Rick Reineke's caution about taking unbalanced stereo (as a headphone output) and connecting it into a balanced input. Many people have come through these forums asking how to fix their audio tracks that have Left-minus-Right problems.

Re: Headphone audio
 

Forgive me for asking what is surely an amatuer question, but at a dance recital, presumably the music is pre-recorded. Can you not grab a copy of the original MP3 file, or rip the CD's to a latop, and then synch/mix them in post?

Re: Headphone audio
 

I use one of these: AV Direct – Audio/Video Direct Box – ART Pro Audio

or one of these for stereo: http://artproaudio.com/product/dual-rdb/

Re: Headphone audio
 

I don't know about MP3 files, but CDs do drift, so depending on the action you can find sync drifting. This was an issue when shooting music videos to CD playback, so the editor had to make sync adjustments when cutting to the music track.

Re: Headphone audio
 

I've never had any Digital source drift once we moved to decent PLL control - mp3, CD, any of the data formats are stable enough for normal sync purposes. Pinching the CDs is a good move - always a good fix!

Re: Headphone audio
 

It’s possible but very time consuming. First you have to convince the director to mail them to you. Most of the time the songs have been customized for content and length. There can be real time issues like in my last recital the cd skipped in a couple of places like wise it can also skip while ripping. That’s very hard to sync because you can’t remove the skip. Sometimes they will restart a song if there is a dancer problem. In addition I’ve found syncing software has difficulty with classical and with ambient that has reverb. Syncing 50 individual songs just isn’t fun. While there would be drift between what the camera recorded and the actual music since the songs aren’t played continuously there wouldn’t be enough time for them to drift enough to hear.

Re: Headphone audio
 

Back to my initial question, plugging a 1/4 to xlr adapter into the board’s headphone jack.
1. What would happens to the channels if you plug a mono adapter into a stereo jack?
2. What happens when you plug a stereo adapter. Because I assume that the left or right channel will be sent through the pin/wire that is reserved for reversed polarity to make it balanced. So what does the camera do since it’s expecting a balanced mono feed but instead is receiving an an unbalanced stereo feed?

I get that because the distance is so small that there are no noise issues sending unbalanced signals.

Re: Headphone audio
 

You get the Left channel, and the Right channel is shorted to ground. Shorting the output of a piece of modern gear is unlikely to damage it as most modern gear is designed to be "short-circuit-proof".

Depends on what you mean by "stereo adapter"?
If you mean something that combines Tip (Left) and Ring (Right) signals together then you should get a proper mix of stereo down to monaural.
But if you mean something that connects Tip to XLR pin 3 and Ring to XLR pin 2, then you will record Left-minus-Right which will typically be horrible and unusable.

Distance is only ONE (and perhaps minor) issue. A much larger issue is ISOLATION between the venue system and your gear. Of course, if you are only operating on batteries, you can probably get away with it. That is why I like the Rolls DB25 iso boxes. So that the interconnection causes no problems for either me or for the venue system.

Re: Headphone audio
 

I would not 'recommend' using a HP output in the first place. It is basically a functional work-a-round when no other options exist. Tying L/R HP terminals together will not damage anything.. in most cases.
PA system power amps are another story.

Re: Headphone audio
 

With a direct-box (DI) method you should be getting mic-level balanced on XLR connectors to your camera. With XLR inputs on your camera, you should be good for up to 300 feet (100 meters) using decent cable.

I myself haven’t used the Rolls DI, but, do look for one with a switchable pad, and take time to set it during rehearsals or sound check. This may be an instrument/amp switch, or, could be a sliding switch with 0, -20db, -40db positions. In theory, a headphone output is close to line-level. In practice it varies widely.

My usual DI is an EWI FB-202 2-ch, which can solve some problems. You can always use just one ch. A specific adaptor cable in 1/4” that takes one stereo to two mono signals is readily available, like a Hosa STP-201 from your favorite retailer or online source.

Re: Headphone audio
 

FWIW, the original (discontinued) Rolls DB-25 had a switchable 20, 40 dB pad. The updated DB-25b has a variable pad pot. Both have a ground lift switch and are passive (does not require battery or Phantom power).
There are others like the aforementioned ART worth looking into as well,,,, specially made for HP outputs on computers and such.

Re: Headphone audio
 

If you're going to be at the venue for the duration, perhaps you can arrange to split the output of the mixer or whatever is feeding the speakers. Or even split the source. If there are multiple sources bring lots of (RCA?) splitters and your own mixer.

I record live music all the time and it's generally not a problem to get some kind of feed from the mixer that isn't the headphone output. I suppose a dance recital may use simpler gear, but it still seems like there has to be a better way.

When I want entirely independent audio I bring my XLR splitter snake and my own mixer.

Re: Headphone audio
 

Patrick's really got e only solution that is business like. If you want it done properly, take everything you need. It's also a perfect example of where advance documents really help. I run a theatre and when I receive a technical rider that says they need a reverse feed of the main microphone sent back to the stage to allow a show recording, it's a two minute job. Same when they ask for feeds to mixers or outputs for cameras. If the video guy turns up 30 minutes before the show and ask for an audio feed, then he'll get a cable about six feet long, and a guess mix. No way to play a track with the people in. If the first number is a tricky one, then the sound op may not have any time to even check what's going down the cable, level wise. The late request is usually then followed by a tap on the lighting guys shoulder asking for more/less/ light, or even changes of colour. Happens all the time and if they cannot turn up for rehearsals, then unless it's on paper and agreed they have priority over the audience, then they get no changes.

Don't forget that for many events the audio equipment is not the venue's and has been supplied by another company. They have no compulsion to do anything, but might if the request is done properly.

Re: Headphone audio
 

I’m starting to change my policy that it’s not enough to request a board feed from the director of the show or the person who’s hiring me. I need the direct contact info for the person knowledgeable with the sound system who will be setting up that board. Because a lot of times the request for a feed never made to the right person. One of the most prevalent trends i’m noticing is they will either rent the equipment or use the venues but then only hire someone to set it up but the day of the show a student will only be there doing simple cues and has no knowledge of the board. This must be a cost saving measure

Re: Headphone audio
 

When I was recording legal edu seminars in NYC metro area hotel ballrooms and such, most of the folks who set up or rented the system were not what I would call "knowledgeable" and did not know the difference between mic and line level.
In my case though, the producers used many the same venues, so after I got to know the hotel's A/V dept. or rental co. folks, they allowed me to integrate the recording set-up with the PA and have full control of both. FWIW, my usual MO, I used the prefader sends for the house sound and the main faders for the recording,.

Re: Headphone audio
 

To be clear, 90% of my live recordings are done on a Zoom H5 getting a mono or stereo duplicate of what the mixer is sending the speakers plus the onboard mics. I've even used the passthrough XLR of active main speakers as my board feed. It works great when the recorder is at the foot of stage with the mics capturing stage noise (amps & drums).

Re: Headphone audio
 

Over the years Rick, Paul, Richard and I have probably written volumes on this board about "What should a video guy do when he needs a board feed." It is an important question with no one single good answer. The answer is based on your own knowledge and kit.

I realise not all of you can carry a complete audio kit designed to make this work for every situation. If your going to accept unknown feeds with little control my first advice is not about how to do it, it is to say "Go for it but do not count on it without a separate solid backup recording in place." This board is littered with the other thread that comes after the patch question "Dude Help!!! I can't use my audio!!!" A backup is not a joke, it is a mandatory life saver for live events. Best advice I can give. Now that I got that out of the way.....

As everyone said the first thing you need in your kit is a DI box, its mandatory. It is like a magic little tool that can take a wide range of crap coming out of a board and turn it into a known and usable signal that can be handled by your patch cables and cameras.

On the kind of cheap mixers found at recitals with a kid standing behind the low end board this is one time when I might not immediately discard classic RCA outs if they are there. Recitals are the kind of scene where you might still run into a mixer (or even a player) with RCA outs. A short RCA connector into a DI box, then XLR for the camera run can work. This will most likely be a Consumer Line Level feed. It's up to you to know what your DI box will do to it and what your camera or recorder wants.

My point is that my kit is built to be versatile. It is centered around DI boxes and pads with a lot of cables and adapters. My goal is always to start by trying to get a balanced signal straight from a good board output and keep it balanced all the way to the cameras or recorder. But, Just as you said Peat, sometimes the real world sucks and you have to punt. When your standing on the 60 yard line and you have to punt you need to know what your doing and have a little luck that the guy on the other team at the end of your cable does not drop the ball.

Kind Regards,

Steve