NTG-1 and feedback with monitor speakers..
 

Hi, I'm a bit of a newbie so I'm sure I'm doing something wrong. I bought a Rode NTG-1 mic which I have mounted on a boom above and in front of the subject's head (stationary) I have the main out of my mixer going into the camera and the monitor out going to two high quality Ramsa PA speakers. The problem I am having is that when I turn up the monitor volume from the mixer, it creates that waaaaooo feedback sound. How does one overcome this?

Move the mic away from the speakers, or move the mic so it isn't pointing towards the speakers. Are the monitors for the talent to listen to, or for an audience?

The mic is pretty far away from the speakers, about 8-9 feet away. Also, the mic is pointed toward the subject and 180 degrees away from the speakers. The speakers are RAMSA WS-A80 http://www.da-av.com/DA/WS80.html and I even tried turning the speakers 180 degrees from the mic too. There's no audience but he has to hear what's coming out of the speakers during recording...

For that you should set him up with headphones.

No go on headphones, he doesn't want to do the headphones thing, and he's making an instructional DVD, would look silly...

Hi Mike...........
 

I think the only way out of this is to fit the guy with a wired/ wireless earpiece linked to the mixer O/P - reasonably unobtrusve and solves the feedback problem once and for all.

Shouldn't be too hard to lay your hands on one.

CS

What does the earpiece do, or what is it for? Do you have a link to one, a brand or model? What is "O/P"

What is it that he has to hear through the monitor speakers? At the very least, why does the mic have to be included in the mix that goes to the monitors? Can't you just leave the mic out of the monitor mix while leaving it in the main? I don't know what you're using for your mixer but with many of them setting up a "mix minus" or independent monitor and main mixes is no problem.

How about a rundown on the full recording situation you're trying to resolve - what you're recording besides his voice and how you're setting it up - we might be able tro offer some suggestions. I'm trying to figure out what the situation might be where a sole performer with an acoustic intrument and no audience needs PA speakers to hear what's going on when he plays while making an instructional video and I can't come up with a scenario where you couldn't just ditch the speakers altogether and have whoever is responsible for sound quality monitor through headphones during each take. A little more detail of the problem you need to solve would help us help you.

I don't see how it would look silly for him to monitor through headphones while on an instructional DVD - after all, 'phones are the way muscians have monitored their own performances in just about every studio recording session that's been held since recording began and so for him to use 'em while recording on-camera, putting them on while playing and taking them off while narrating, would look totally professional and be perfectly logical. But that's just me.

The earpiece Chris was referring to would be an in-ear monitor, also called ear-canal headphones, used instead of regular headphones. (NOT the same thing as consumer earbuds, BTW.) Shure makes a selection of 'em and I've heard very good things about the Etymotics brand - check out their website. Very common in live performance these days in lieu of or in addition to on-stage monitor wedges to provide feedback to the performers while also providing them hearing protection. When used in film and video, they're often used either wired or wireless in conjunction with what's called the "IFB" or "Interruptible Foldback" system to unobtrusivly provide a mix-minus feed to the talent. They're the ear pieces you'll see on a lot of news anchors if you look closely. See "IFB" on Wiki.

He has to hear his guitar, as well as background music through those monitor speakers. The mic has to be included because the mixer sends everything through the main and monitor outs.. I like the NTG mic, we bought it to overcome all the hell that comes with a lavalier and it's doing well but now this other problem has come up...

What brand/model mixer do you have, does it have an AUX bus you can use? What other mics are you using beside the shotgun for his voice?

You're not trying to use the same mic and mic positioning for his voice and to pickup the guitar are you? Can you keep the monitors off while he's talking, then fade the mic down and bring the monitors up when he switches from talking to playing? (I don't see why he should need to hear himself in the monitor even if he is playing to a pre-recorded backing track.) Or perhaps better, cut between and do the talking and record the playing from different setups altogether? Trying to do the whole thing in one take so the entire lesson is from one camera position and with one framing doesn't seem like a visually very interesting approach anyway.

It's an Alesis MultiMix 6FX
http://www.alesis.com/product.php?id=36

(It's in a compact rack type situation) To answer your question, I wouldn't be able to fade the monitors in and out because it's an instructional video. There's talking and playing, sometimes simultaneously. I probably should have specified all this when I started the thread, sorry =)

I have a channel for Guitar, Mic, Background MIDI track. The main out goes to my video camera, and the monitor out goes to those RAMSA speakers...

It seems like it worked better when I turned the main volume up to about 2 o'clock on the mixer (lowering the input volumes on my cam), and kept the volume on the mic channel lower. Then I was able to bring the monitors up where I wasn't getting that loud waaaaoooo feedback (if that's what it's called) sound AS much, but it's like right on the edge of happening which is rather annoying..

The mixer has an AUX Send - a classic use of an AUX is to provide a monitor feed to the talent so try this. Forget about using the mixer's monitor outputs at all - they really are for a studio situation where the speakers are not in the same room with the talent anyway, that's why they're called "control room monitors" <grin>. Also, there's no need to provide him with stereo monitoring, mono should be just fine for this purpose. So instead of both speakers on the monitor output, connect just one of the speakers to the AUX Send output. Send the Rode mic plus the guitar plus the background track to the main just as you are now. Also send the guitar and both channels of the background track, but NOT the mic, to the Aux Send. Voila! The classic mix-minus to provide feedback to the talent yet no mic in the studio mix to trigger feedback howls.

As for talking and playing at the same time, that's where you need to step in and exercise your authority as the director - what might work in person won't work on video. No matter how expert he is on the guitar and on what works musically, you're the expert on what works in video. The audience can pay attention to what he's saying or they can pay attention to what he is playing but I'll guarantee they won't be able to do both at once and make any sense out of it at all.

Ahhhh interesting! I didn't even know about that AUX send, or at least pay any attention to it. I will try that tomorrow. Just to be clear, I'm reading the manual
http://www.alesis.com/downloads/manu...6FX_Manual.pdf

And it appears that in order to send a channel to the AUX send output, you do that by raising the AUX knob on that particular channel. So if I don't want to send the MIC channel out to the AUX, I would just lower the knob all the way down?

Also, I am now wondering about this:

"This knob controls the level of the internal effects and the aux
send. If the EFF/AUX switch is engaged, this knob controls the
level of the aux send, and if the switch is in the up position, the
AUX knob controls the internal effects send level."

Is this an either/or situation? Meaning, if I push the button down to send it to the aux send output, do I lose the effects? That was the reason this mixer was selected for this compact rack is that it has internal effects. So for example, the guitar - That IS something I want to send to the AUX send output so he can hear it. So I should press that button down and increase the fader knob. I'll have to see what that does to the effects being used on that channel for the guitar, I hope it works!!

You are correct - turn up the Aux fader on a channel to send it to both the the Aux Send and the Main and turn it down to send it to the Main only.

I don't have one of those mixers but according to the block diagram in the manual it is an either/or situation with that switch so you can send the Aux feeds from the input channels either to the internal fx processor or the external Aux Send but not both at once. But unless you simply have no choice, NEVER record with any effects applied, other than perhaps light equalization if needed on a channel! Always record your performance dry! The time and place to add effects if you're going to use them is in post production where you can try out different mixes and change your mind if it doesn't work the way you'd hoped it would. If you do it when shooting, you're committed and there's no way to undo the damage if it doesn't work.

Hmm... Well what other choice would I have? The L&R outs from the mixer go into a direct box and come out as one XLR that plugs into the XLR input on my camera. So when I capture the tape, I have a video and audio stream (consisting of the guitar, mic, and tracks). Is there another way to do it? We've always just gotten the audio the way we want it to sound, then just record; didn't know there was another way? In addition, the guitar player won't want to play with a dry sounding guitar (no reverb), makes it difficult..

Is he unable to play the music without hearing the reverb??? If that's the case you have no choice but to lose the speakers and get him to wear headphones or in-ear monitors. If he can play it but just is worried it won't sound right in the video, convince him that he's not doing a live performance but making a recording and different rules apply - the material he's recording is only the raw material for the final soundtrack which is actually going to be assembled in post production. Either that or get another mixer as well as the one you have or upgrade your current mixer to one with more aux sends and more flexible routing options.

Another option occurred to me just now. You said you were taking the main outs to a direct box and then to an xlr input to the camera. That sounds like you're mixing them to mono and only using one channel of audio in the camera. Is that the case or do you have a 2-channel DI box, or do you have two direct boxes? If you're only using one channel in the camera, take the mic off the mixer completely and send it directly into the second camera audio channel, doing the mixdown with the music tracks in post. The guitar and backing tracks would still go to the mixer, monitors, and DI box just as they are now.

Steve House is a saint. Very good work, Steve.

Ty Ford

Anytime it's a live sound situation, the sound system needs to have the proper EQ curve for the space and mics.

In addition to the good advice you've received, the send to the speakers/amp should be routed through a graphic EQ. Play a strong signal of pink noise through the system and adjust the frequencies curve using a spectrum analyzer.

Or...gradually turn up the volume to the point of feedback and identify and reduce the offending frequencies.

Simple, don't feed the mic to the PA.

This was outlined in great detail by Steve House's reply.

Ty Ford

Trust me, a stubborn old musician is set in his ways. He wants to hear the guitar with the effects as he plays as he has done forever =)

I do have another mixer in a Yamaha recorder I've used before so that's a possibility....

The direct box I'm using is this:
http://www.rolls.com/products/db25.php
It takes in two 1/4" inputs from the mixer and outputs one XLR which goes to my camera. Honestly I don't even know what the direct box is for, someone told me I need one, so I got it and it seems to work ok...

If I recall correctly, I tried to do something similar so I could have the guitar and music on two channels in case one was recorded too loud or too soft. From what I remember, when I tried to capture the tape to the computer, it only captured one channel of audio. Do I have to use the same camera I shot with to capture the tape (and both channels of audio)? What I do is shoot with my good camera and capture with an older Canon miniDV camcorder (to save as much heads use on the good cam)

I really appreciate all the replies here!!

Yep, the DI box is a mono box. The two inputs are in parallel so you're mixing the L&R outputs of the mixer as they go into the box. Combining L&R by simply Y'ing them together (which is what that's doing, just not using a "Y" cable to do it) may or may not compromise your sound. So if the mixer is going to the DI and from there to the camera, you're only using one of the camera's two stereo tracks so far. Don't have a clue why you only got one audio channel when you captured a stereo recording before. That's not what's supposed to happen - you should have gotten a single stereo track with two channels and most editing software should let you then split them off into two mono tracks.

You said earlier that you were mixing the mic, the guitar, and a MIDI background track. The shotgun mic is obviously going to be mono but what are your signal sources for the guitar and the MIDI track? I assume you're getting the guitar as a mono signal off on its pickup, is that right. But what's the MIDI track coming from and is it mono or stereo?

The guitar signal goes into a PreSonus Bluetube (to give it some juice and warm it up) and then out to the mixer into channel 1. The MIC goes into the other channel of the Bluetube and then out to the mixer on Channel 2. The MIDI tracks are played from a MIDI player which we're taking the MONO output of straight into channel 3 on the mixer. It's been a long while since I tried using both channels on the camera to capture different audio so I'll give it a try, among your other suggestions, today.

Because of all these problems, I'm allowed to purchase another mixer - Do you have any recommendations on what I should get? The other mixer I mentioned I have is a Yamaha MD4S. Should I be using a different direct box, do I even need a direct box..... I'm not shooting hollywood epics here, just instructional DVDs =)

Does your camera only have mic level inputs or can you send it line level?

It's a Panasonic DVC-80, on each of the two inputs, there is a switch for mic or line level. I'm going to try plugging the mic directly into the camera from the Bluetube on Input 1 - So I don't destroy the camera, should I have that input on mic or line level?

Set both of your camera's XLR inputs to line level and forget the DI box (the DI box is to take line level, generally direct from a guitar or similar instrument, and drop it to mic level wihile matching impedance). Send the mic to the Blue on Ch1 and send Blue's Ch1 output direct to the camera on Input 1. Send the Guitar to the Blue on Ch 2 and Blue's Ch 2 out to a mixer line input. Send the mono MIDI playback to a second line input. Setup your reverb and monitoring as you like, monitors on the control room outs. You can use either mixer output channel to send to the camera since you're already in mono and the two should be identical. Convention would be to use the left so send the left main out to the camera input 2 through a TRS to XLR cable.

Try like heck to convince him headphones look cool and professional. Point out the Sirius radio commercials where all the talent is wearing cans. I have a copy of Roger McQuinn's (The Byrds, "Mr Tamborine Man") DVD "Guide To Home Recording Using a Computer," an instructional DVD not unlike what I'll wager you're shooting. And when McGuinn's playing and singing, guess what ... he's wearing headphones and singing into an on-camera studio vocal mic. Show your talent the video clip in this link, I think he'll agree it doesn't look at all silly or obtrusive

http://www.homespuntapes.com/prodpg/...1129&prodType=

The idea is to try to prevent bleed from the playback/monitoring speakers over into the same channel as the voice and you're still going to get that which could give you some headaches in post as you mix the two together. But at least this arrangement will kill the feedback.

I did it! I was a little concerned because that NTG mic picks up quite a bit more than voice - it was picking up the guitar playing from the guitar itself. It sounded very strange to hear that in the headphones, but when I captured it and dropped it onto the timeline, duplicated the audio track, and then picked left channel only for one track, and right channel only for the other track, it sounded pretty good. I can always just cut the power to the mic altogether while the guitar and sequencer are playing at the same time, or I can cut it in the post production as well. But it seems to give everything a fuller sound as it picks up the sounds in the room such as the guitar and the monitor speaker playing the guitar and sequencer.. The NTG mic is superb! The audio from it is crystal clear, couldn't be happier to NOT be using that lavalier! One thing I noticed is that I have to bring the gain on the Bluetube almost all the way up to get a hot signal on that mic, before with the directbox, it didn't need that much juice. Are you positive the setting on the camera should be LINE instead of MIC? If you want I can post some audio samples from our test.

It would be great if I could have everything on a separate channel but I guess that isn't possible with only a left and right in the camera and on the tape..

Glad it's finally working for you. AFAIK your camera should be set on line levels, since that's what both the mic pre amplifier and the mixer are outputting. Just how hot are you trying to get it in the camera?

Which output connection are you using on the Blue for the mic channel? The XLR outpout is pro line level, +4dBu when the meter reads 0VU but the TRS output is -10dBv, a lot lower level! Your camera wants pro level line so be sure to use the XLR connector for the line for the mic channel from the preamp to the camera. When the 0VU lights are illuminated on the meters on both the Bluetube and the mixer you're getting +4dBu output, pro line level. The camera specs say its line input sensitivity is nominally 0dBu, which is normal for digital equipment. So if the 0VU lights are flickering on the Blue, you should be seeing the camera's meter somewhere around -12dB with normal speech. Also be sure you don't have the -20db pad on the Blue switched on in the mic channel.

I forget where you said you had the mic positioned. It should be above and to the front of the talent, directly above the line between his face and the lens, aimed at about a 45 degree downard angle towards his mouth. Get it as close to him as possible without intruding into frame. You might try a stage wedge on the floor in front of him instead of the PA speakers if he insists on no 'phones. Position the mic first for best voice quality, then put the wedge on the floor farther away from him so a line from the wedge to the mic would be at 90 degrees to the axis of the mic, that way it's in the maximum null of the mic pattern. While wearing phones to monitor, experiment moving the wedge back and forth until you find the spot of least pickup. That should help minimize the bleed from the monitors. There's no way you're going to eliminate it completely without getting him to wear cans. The place to clean up the bleed is in post - when he's playing, mute the track from the mic.

I'm using the XLR connection on both ends from the bluetube to the camera. One thing I should note is that I didn't have a short cable for that connection so I'm using a pretty long one, probably 25 feet or so - Does the length of that cable matter much?

The mic is indeed positioned above and slightly in front of the subject's mouth, aimed down at the mouth and out of the picture frame.

I have that RAMSA speaker pointed at him about 10 feet or so in front of him.

Here's a few mp3 samples I made from the recording below. The first two are the same section on the timeline, I just muted each channel and encoded them separately. (I know the mix between the guitar and MIDI track is bad) The third one is both channels together with some talking and guitar, no sequencer:

Guitar & MIDI sequence channel

Mic channel

Talking & Guitar, both channels

Not bad - you're right that the balance between the guitar and the midi track could be better but not bad. The best situation would be if you could record all three tracks individually rather than worrying about the balance of the guitar and backing during the shoot but since you're stuck, not bad.

25 feet on the XLR cable shouldn't be a problem at all - line level balanced cables routinely are run as much as several hundred feet. The voice sounds fine for level, he still may be a little distant or slightly off the mic - try aiming it down a little bit, more towards his upper chest than his mouth - but not distractingly so and as far as level goes you can increase it a tad in post to balance it out with the music track. What are you editing in? Where are your camera's recording gain controls set and what are the meters on the preamp and in the camera showing for his voice?

Thanks! I was worried because it was hard to listen to in the headphones while recording having two different thing going into each ear but it came out good for a first try. I use Sony Vegas for the editing. The gain level for the mic channel on the camera is 12:00 (halfway point) The gain on the Bluetube for the mic is almost full up (which I don't believe it should be??) The Bluetube makes signals hot as hell so it's weird that I have to turn it almost all the way up to get decent volume into the camera.

As for exact meter levels, I don't recall what they were on the Bluetube, but on the camera I try to keep everything between -12 and 0. I hate buying or watching videos where I have to increase the volume so much to hear it. Plus I usually use the W1 Limiter (http://betabugsaudio.com/plugs.php) (I didn't use it in the clips I posted) to make the audio sound much bigger and better.

For our purposes, I think this setup will be just fine, although I'm sure something is wrong that I have to boost the gain so high on the Tube...

No, nothing is wrong, in fact, perhaps you should lower it a bit. You're under the mistaken impression that you should be hitting that high on the camera meters and in fact you may be recording too hot and risking clipping, especially on the guitar track - I didn't hear any but you're in the range where it's a danger. Peaks should just be touching -12 dBFS or maybe a little more thereabouts. You don't want peaks to even come CLOSE to full scale. I don't what you did with the levels when you made the tracks you posted but when I loaded them into Soundforge, the voice track peaked at -1.7 dBFS on the guitar noodling with the voice averaging about -6 to -8 dBFS. But the guitar/seq track lit the clipping indicators at several locations and the VU meter shows a max level of +9.5dB so if that's what you got in the camera it's definitely too hot.

If you had a mixer with tone, as a starting point you'd send a 0VU tone to the camera and adjust the camera levels so it read about -20 dBFS in the camera's meter. Then if the material wasn't too "peaky" you might record a little hotter. You said you can't stand programs that you have to turn up and I agree with you but that's not something you adjust in the camera or recorder on set. Don't make the mistake of thinking the level on the tape in the camera is the level it will be in the final program - your goal when shooting is to get the full dynamic range of the performance on the tape without clipping or distortion - post is where you adjust levels for what is heard in the final program.

Thanks for telling me that. This was just a quick and dirty test, but no, I never have anything clipping and I rarely adjust the volume in post because I get the volume loud enough when the filming was going on. So you're saying that the audio meters on the camera should never go above that -12db as seen below on page 45:

http://www.mediacollege.com/equipmen...ra/agdvc80.pdf


What I've been doing was recording in the range between -12 and 0, but never quite hitting 0.

Does -12dB on the camera meter (on the tape) equate to -12dB in Vegas? I guess I worry that if I record the volume too low on the tape, that even if I increase it in post it won't be high enough and that's why I was trying to record as loud as I could without hitting 0dB.... I'm learning a lot here, thanks again!

I was just looking through the manual and read this on page 49:

You're saying to set it to LINE because it's coming from the Bluetube and not the mic directly into the camera, correct?

Yes, that's correct. The Blue is a preamp, which means it is already boosting the mic level to line level.

I won't say it should NEVER go over -12 but that's the general ballpark of the average levels you should be shooting for. You can't really say that -12 on the camera will equate to -12 in Vegas because of meter response times - who knows for sure what Panasonic has set theirs up for - but they should be pretty close most of the time. -20dBFS sine wave usually corresponds to -12 to -14 dBFS on voice waveforms.

Alrighty then, I'll be sure to let you see the final outcome of this video when it's done, we're probably going to shoot it tonight...