Question about using a mic properly.

I

ironpony

Carbonite Member
I was looking at what other audio people had to say. I have the FR-2LE field recorder, which records in stereo. Some say to plug in the mic with a Y-cable. Then turn up one of the mic trims so that normal volume of dialogue records at a level of 12-6. Then turn up the other mic trim, so only shouting and screaming reaches 12-6. Then I can choose the best of both tracks in post.

Others say that using a Y-cable is a mistake, cause it cuts the mic signal in half, thereby weakening the quality, and to just plug the mic into one of the channels instead, and remove the other channel in post. But if a Y-cable cuts the signal in half, then why use it that way?
 
A "Y-Cable", first of all, is only an option with unbalanced signal sources; pretty much any quality mic will use a balanced connection. Also, you DO not want to use a Y cable with a phantom powered mic if you don't want to damage the mic and/or recorder.

As ggrantly says... do this internall within the recorder if you can, or use a device in front of the recorder that can properly split the signal (a splitter or mixer).
 
Well I've already tried the Y-cable with the phantom power recorder before and nothing got damaged at least I don't think. The recorder supplies the phantom power. What do you mean, do it internally?
 
Many recorders allow you to route an input to more than one destination... I'm not familiar with the FR2LE, but, for example, the Panasonic prosumer cameras have a switch that allows you to send the signal from a single mic input to both preamps, so you can set the levels differently and record them on separate channels.

I don't think my 744t will do this in a useful way (it can do a lot of signal routing, but I think it's all in the digital domain after the converters). But with a good piece of equipment like the 744t (and presumably the FR2LE), this kind of trickery isn't really necessary. Record at 24 bits, and set your levels conservatively, and you won't have noticeable noise when adding gain in post. This trick is found on cameras where it's most useful, because their audio systems have a lot more noise, and record with 16-bit precision, so you have a lot less latitude to boost levels in post.

So I'd say... if the FR2LE can do this internally, why not? But I wouldn't worry about it if it can't.

As to phantom power... A Y-cable connects the power source and sink in unintended ways, which you don't want to do. Phantom power should flow from one input into the mic and back to the same input. The Y cable will send phantom power from two inputs to the mic, and directly connect the two phantom power sources to each other... not a good idea. In the short run, you don't know what it's doing to your audio quality; in the long run, you can indeed damage equipment.
 
ironpony said:
I was looking at what other audio people had to say. I have the FR-2LE field recorder, which records in stereo. Some say to plug in the mic with a Y-cable. Then turn up one of the mic trims so that normal volume of dialogue records at a level of 12-6. Then turn up the other mic trim, so only shouting and screaming reaches 12-6. Then I can choose the best of both tracks in post.

Others say that using a Y-cable is a mistake, cause it cuts the mic signal in half, thereby weakening the quality, and to just plug the mic into one of the channels instead, and remove the other channel in post. But if a Y-cable cuts the signal in half, then why use it that way?
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I'm in the "don't use a Y cable" camp. If you want to send a mic into two inputs, you need a proper mic splitter to divide the signal, not just a Y. Y'ing joins the two inputs together in parallel, changing the impedance the mic sees and opening up the possiblilty that the two will interact with each other in unfavorable ways. See if your recorder can route one mic input to both recording channels on its own with different level settings for each - RTFM.
 
Okay thanks, I won't use the Y-cable. And no my recorder cannot send one signal to two inputs internally. If I knew the FR2LE could not do that I would have got something else, but it's too late now. So what do I do then to keep the levels at a good gain, while not peaking when it comes to yelling? I could have the boom holder move the mic away, but I find that that sometimes changes the gain, and it will sound not as good sort of.
 
I routinely split balance, phantom powered condenser mics to two mixer channels - for live use, and the only real issue is doing it to two separate mixers. The reason is that the phantom supply rail is connected to each mic socket by two matched resistors, so using the Y split reduces the current limiting of the phantom supply. In practice, with Soundcraft, Allen and Heath and Yamaha mixers this has caused no issues whatsoever.

Mic splitting to two inputs does result in a slight drop in signal level, but in most cases, it's so small that increasing the channel gain isn't even necessary. In fact, many video cameras do this internally to route the front mic to ch 1 and 2 if you wish.

With a dynamic range so great that the noise floor is very low, the loss is too small to worry about. Many larger PA systems, like those at festivals run with passive splits on all the input channels to allow the monitor mixer and foh mixer to share the inputs. It is so common as to be almost standard. Most mixers are also designed to not suffer problems when a mic split applies 48V 'up the spout'. The general rule is that if two mixers are linked passively, then just one supplies phantom, the other doesn't.

However - having said this, as digital streams are not recorded separately, but all channels embedded together, there's no real point in recording two channels with the same content. It made sense in the old days when recording analogue, just in case dropout on one channel made it unusable - having a duplicate was handy. With digital, any dropouts on tape or memory glitches rouine everything - you won't get a fault on just once channel. Any duplication can be done in the edit suite with a copy and paste.
 
Paulears… not sure whether you're talking about a proper splitter (passive or not) or just a y-cable?
 
Well I'm kind of lost on what to do now, having heard that. I can't set the levels lower, cause otherwise it's too quite. What I could do is just record with the levels set from 12-6, for normal volume dialogue, then if any clipping occurs from sudden yelling, I'll just ask the actors to do ADR on it again in post.
 
paulears said:
...However - having said this, as digital streams are not recorded separately, but all channels embedded together, there's no real point in recording two channels with the same content. It made sense in the old days when recording analogue, just in case dropout on one channel made it unusable - having a duplicate was handy. With digital, any dropouts on tape or memory glitches rouine everything - you won't get a fault on just once channel. Any duplication can be done in the edit suite with a copy and paste.
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With digital the event you're insuring against with the insurance track is not dropouts but just the reverse, levels rising up to the point they cause clipping. With an insurance track 6 or so dB lower than the main track, you're protected in the event a sudden loud sound drives the main up over the top. Of course, proper gain staging, knowledge of the scene so you can ride gain in anticipation of level changes, and a decent mixer with good limiters goes a long way in preventing that sort from happening in the first place.
 
ironpony said:
Well I'm kind of lost on what to do now, having heard that. I can't set the levels lower, cause otherwise it's too quite. What I could do is just record with the levels set from 12-6, for normal volume dialogue, then if any clipping occurs from sudden yelling, I'll just ask the actors to do ADR on it again in post.
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There shouldn't be any "sudden yelling" that takes you by surprise. The sound recordist needs to know the scene as well as the actors and the director. When the scene gets to the point they start to yell, in the beat before the yelling starts, you back down the gain a bit in anticipation.
 
Well my sound guy dropped out so lately, I've been using whoever I can get to show up to do it. I will test and set the gains for the room before hand, and then hand the the equipment off to them. I will try to tell them when the sudden yelling occurs, but couldn't that time, cause the actor decided to yell louder than I had anticipated, but I liked it so much, I decided to do more takes of it. The guy with the boom and headphones did not tell me that he heard any clipping though. Even though it says that it clipped, it doesn't sound like it clipped really, so maybe the FR2LE has a built in limiter. It does get a bit static-ish though.
 
ironpony said:
Well my sound guy dropped out so lately, I've been using whoever I can get to show up to do it. I will test and set the gains for the room before hand, and then hand the the equipment off to them. I will try to tell them when the sudden yelling occurs, but couldn't that time, cause the actor decided to yell louder than I had anticipated, but I liked it so much, I decided to do more takes of it. The guy with the boom and headphones did not tell me that he heard any clipping though. Even though it says that it clipped, it doesn't sound like it clipped really, so maybe the FR2LE has a built in limiter. It does get a bit static-ish though.
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That static is probably the clipping - it often sounds like a rattle or crackle. And he may not have heard it in his phones because it might not have been there - monitoring the audio inputs, as is usually done, takes the signal for the phones off while it's in the analog realm before the A/D converters. Clipping occurs at the converter, when the audio tries to drive the numbers up past 0dBFS. Some recorders allow for confidence monitoring, giving the option of listening to the actual track with a few seconds delay immediatly as it's being laid down, and that would have made it audible.
 
And there's the rub. Funny how if the DP for Camera Op dropped out, no one would even consider just using whoever they can get to show up to handle the visuals.

When production sound is treated with the same attention as image, the results are very predictable. There is nothing magical or mystical about obtaining quality production sound, it's been done for decades. Proper equipment+skilled operator+appropriate planning=quality. Figure out and correct which items you're lacking, and your production sound will improve. Trying it without all three elements, and the results will be, at best, unpredictable, and often, sub-par.

ironpony said:
Well my sound guy dropped out so lately, I've been using whoever I can get to show up to do it.
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There are lots and lots of places in this big wide world where a capable and professional film sound person simply cannot be found, and the cost of bring someone in from another city, feeding and housing them for a few days would often quadruple the budget of many of the pieces I do. I have spent pretty much my entire career working with students, where my job becomes half shooting the piece and half instructing them on how to do their part of the work. I enjoy this to an extent, but it would be nice to work with a pro crew from time to time. However, in many situations that is simply not possible. I am sympathetic to the "whoever I can get to show up" protocol for hiring crew people, because sometimes it's the only way to get the job done. (And if it was good enough for Ed Wood, it should be good enough for me!)

- Greg
 
Right… but I think gpforets point is that people always think sound can be "shortstaffed" this way, but never think that visual recording can.
 
A passive splitter - is a Y-split, as in 1-1, 2-2 and 3-3. Transformer splits offer electrical isolation, but the insertion loss is a bit greater (still perfectly fine, of course) and then we have active splitters that have electrical isolation plus unity gain. My stage boxes have 24 males, and 24 females, so if you need a split for a monitor mixer, just stick in an XLR and make sure phantom is off. This is a nice simple system - and I've never had a problem with it.

It is often thought transformer splits protect against shorts, providing safety isolation, but oddly, they don't and a short on the cable going to the PA mixer will still take out the audio to the recording truck, or monitors. Losing 3dB in a split is easily made up in the preamp.

I must admit I'd not thought of the lower gain, more headroom on the split track - and that could be something quite handy. When you have a rookie sound op, a limiter can be a very handy thing.
 
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