Hi there,

i cant´t seem to find an answer to that question.

When i record with a camcorder and one XLR mic, i usually record to two channels (left/right). I set the level of one channel lower than the other to have a save track to prevent clipping.

So to make it clear: I just want to use 1 microphone and record 2 channels of it with different levels.

Is that also possible with these recorders?:

1. Zoom H4n
2. Tascam Dr-100
3. Marantz PMD 661

thanks in advance,
Marcus

I'm pretty sure that all of these recorders will do it but I own a couple of the Dr-100's and I can tell you for sure that it will. You just need to choose a mono source and then you will have independent control over L/R.

Zoom H4n - Yes

See: http://www.dvinfo.net/forum/all-things-audio/487699-h4n-firmware-update-enables.html

thanks,

but I am not sure about the zoom h4n.

The firmware update says:

1. Added the function that recording level of INPUT1 and 2 can be set individually.

So as i understand it: When I use 2 XLR microphones I can set the levels for each Microphone seperately.
But I only want to use 1 microphone and record 2 channels with different levels.

Is that also possible?

I'm a little lost. . . you say choose a MONO source to have separate control of L and R?

I just got a Tascam DR07, has mini plug LINE and MIC ins (one of each). Seems like to get a stereo signal you'd choose stereo, no? That's what the manual says. . .it says mono will give you a mixed signal of all sources on L and R.

I would generally plan on using a mixer with this thing. . .you'd control the levels of the multiple mics with the mixer, no? Set tone and leave it alone after that on the recorder.

just wire your mic into both input channels. an xlr y-cord or similar works fine for this...

Sorry for the confusion. I will try and explain it better what i usually do when i use my camcorder.

When using my Camcorder (Panasonic HMC150, AVCHD) i plug in my ME66 microphone into the XLR-input labeled "Input 2" and record a stereo signal together with the video on an SD-card.

For channel 1 i select "Input 2" and for channel 2 also "Input 2"
Then i adjust the levels for both channels using the gain knobs for channel 1 and 2.
To prevent clipping i usually set the level for channel 2 a bit lower than for channel 1.

When i ingest the material into FCP for example i have a stereo audio track where one track has a lower level than the other.

So my question was if this is also possible with the above mentioned audio-recorders? Can i use one microphone to record 2 channels and set the level of each channel individually?

Hope i could make things a bit more clear. Thanks for the help!

Ok so a xlr y-cord cable could be a solution. Are there any disadvantages when using such a cable. Is the signal still as good as usual?

thanks,
Marcus

Hi Marcus,
This is a reply I posted a while back to a similar question.It may work for you:

ZoomH4n Menu - Input - Mono Mix On.
Then go back to the main screen and press Rec once to standby.See Mono-000.wav on screen.With your mic connected to input one you should see levels on ch L and ch R. (see Zoom H4n User manual page 072).

Also if your recorder has the most recent firmware update you may be able to set separate levels for ch L and ch R. I am not sure this can be done in Mono Mix mode. If it can then you will be able to set the recording level lower on one channel as has been already mentioned.
I have not used this setup.Make sure to do some test recordings.Good luck.Neil

as long as the y is short (1 foot) and wired properly with shielded cable then there should be no degradation of signal.

I was just wondering if it would work to use the Y cable and put a 10 or 20dB pad one branch of the Y so you didn't have to fool with independent levels in the menu. Just a thought.

as long as the y is short (1 foot) and wired properly with shielded cable then there should be no degradation of signal.

No degradation, but when Y-ing (splitting) the signal you are effectively dividing the signal into two, so your levels will be -6dB at each input (50%).


@Marcus Rieger
I just tried this on my H4n and without Y cable it will not work. As long as you have the “1/2 link” disabled, you can’t “mono mix”.

On the Zoom H4n you cannot get one input onto both channels with separate levels. I have the latest software and tried to do this a few days ago. If you choose Mono Mix On it will be identical levels and if you turn it off the input will only record to one channel of the Zoom.

Ok so it doesnt work with the zoom.

Regarding the Y-cable. If i understand you correctly Robert, the signal will be more silent when using the Y-cable than when not using it. So any preamp noise of the recorder will matter even more, because i have to rise the levels?

thanks guys!

Actually, we need a little math to figure the actual amount of loss. It depends on the actual source impedance of the mic, and the actual input impedance of the recorder.

50 years ago, the answer was a little simpler. Most mics had a source impedance somewhere around 200 ohms. Most recorders had an input impedance somewhere around 200 ohms. If you connected one mic to two inputs, you would be dividing the power from the mic (not the voltage) in half, so the level at a given input would be roughly -3dB lower than it would have been if the mic had been connected to only one input. (Actually it would be slightly lower than that, because you'd now be technically putting more of a load on the mic than it was designed for; that causes some internal losses within the mic.)

Things are different today. We have largely migrated over to a situation where recorder input impedances are typically higher than mic source impedances. For example, the AT4050 source impedance is listed as 100 ohms. The DR-100 mic input impedance is listed as 1.2k ohms per channel.

This is really a nicer system. We have a low impedance source feeding a high impedance load. That's actually similar to our AC power distribution system where a low impedance source (the power transformer) feeds high impedance loads (light bulbs, etc.) So we don't have to worry about exact impedance matching and, therefore, we don't have to worry about power division (as we did in the "old days"). One light bulb does not become half as bright when we plug in a second light bulb.

To do the calculation correctly, you need to consider the mic as a Thevenin generator consisting of a pure voltage source behind a resistance (the mic's source impedance).

OK, let's consider an example with the equipment above, an AT4050 feeding either one or two mic inputs on a DR-100.

For the sake of doing the math, imagine the mic is in a test chamber with a constant tone from a speaker. We adjust the speaker level so the mic is putting out 1.0 volts open circuit... in other words connected only to a very high impedance voltmeter or oscilloscope.

Now let's connect the mic to just one mic input on the DR-100. At that point using the Thevenin equivalent circuit, we've created a voltage divider with a 1.0 volt source voltage, flowing through a voltage divider consisting of a top leg of 100 ohms and a bottom leg of 1200 ohms. The input of the recorder is the junction of the 100 ohm and 1200 ohm resistances. The voltage at this junction is 1.0 * (1200/1300) = 0.923 volts.

Next, let's connect the mic to both mic inputs. At this point the total load impedance is the parallel combination of two 1,200 ohm loads, so it is 600 ohms. We now have a voltage divider with a top leg of 100 ohms and a bottom leg of 600 ohms. (The recorder input is the junction of the 100 ohm and 600 ohm resistances.) The voltage at this junction is 1.0 * (600/700) = 0.857 volts.

Finally, we want to know how much lower the level will be, on a given channel of the DR-100, when the mic feeds both channels, compared to when the mic fed just one channel. dB is a ratio of two quantities, with the ratio expressed in logarithmic units. In this case, one quantity is the input voltage with just one channel fed, the other quantity is the input voltage with both channels fed.

The calculation is straightforward. First we take the ratio of the new (2-channel) signal to the original (1-channel) signal. That ratio is (0.857v)/(0.923v) = a ratio of 0.928. To find how many dB lower the signal has become, take the log of 0.928... the log is 0.032. Then multiply the log by 20, and the result is -0.64dB.

So, happily, we find that when an AT4050 feeds two channels on the DR-100, the level on a given channel is only -0.64dB lower than when that mic feeds one channel. (But the result will be different if the mic's source impedance is different, or if the recorder's load impedance is different.)

Note that this result is very similar to the way your line voltage (measured at the wall outlet) drops only slightly when you plug in a second lighting instrument... because the load impedance of the lighting instrument is much higher than the source impedance of the power transformer out on the pole (including the series resistance of your house wiring).

So, in conclusion: good news! The level will drop very little when you connect the mic to both channels, compared to only one channel.

If you tell me the exact mic and recorder in question, we can look up the source and load impedances, and perform this calculation again for your specific case.

I was just wondering if it would work to use the Y cable and put a 10 or 20dB pad one branch of the Y so you didn't have to fool with independent levels in the menu. Just a thought.

Yes, Jim, that's a good idea, and that would work just fine! Such a pad could be made using just three 1/4 watt resistors... total cost under $1.00 (plus cost of connectors, of course).

If we want to make the pad accurately 10 or 20 dB, we need to know the source impedance of the mic and the input impedance of the recorder. Tell me the specs of the equipment in question, and I can easily calculate the resistor values.

Wow thanks for the detailed answer. I swear i read it twice from beginning to end, but even so i am just starting to get the principle of it. I don´t know enough about electricity and sound to follow along.

right now i am not sure what microphones and recorders my audio kit will consist of. Probably a Rode NTG2 or NTG3.

I am also thinking of a different setup, because i listened to some samples of the zoom H4n and it has quite some noise in my opinion, as has the Tascam Dr-100. The Marantz PMD 661 is better in my opinion, but but has no limiters...

So another way could be to buy a Sound Devices MixPre with great preamps and limiters and feed that into a Edirol R-09. I am thinking about the Edirol R-09 just because thats what they use in an B&H Promo video. Although they use it together with a Sound Devices 302. I don´t know if it works better together with the Sound Devices mixers than the other recorders or not.

Klick on the "Item Demo" button to see the video at B&H:
(Edirol / Roland R-09HR Portable High-Resolution Audio R-09HR B&H)

It seems the Problem with the other recorders is, that you don´t want to just connect the XLR outputs of the Mixer to the XLR inputs of the Zoom H4n for example because then you still use the noisy preamps of the zoom. You have to use line in. Then the problem is that the signal is too hot. Maybe the Edirol recorder can compensate for that? Or maybe i can just use a real cheap recorder when using line in?

Lots of things to think about :)

Again thanks for the answers, much appreciated!

The calculations are based on the fact that any signal source like a microphone produces a voltage, and also has some internal resistance. (In the case of a dynamic mic, this is easy to imagine, the internal resistance is the resistance of the thin wire in the winding of the mic coil.)

And any typical load, like the input of a recorder, has some measurarable resistance.

When you connect a signal source to a load, the voltage generated by the signal source is actually divided between the source's internal resistance and the resistance of the load.

My explanation would be a lot easier to follow if I were at a whiteboard and had a laser pointer. ;) Meanwhile, you might want to search for "Thevenin generator" or something similar. (Of course like all info found in the internet, some might be right, some might be wrong, some might be clear, and some might be badly explained. YMMV... Your Mileage May Vary as they say in the automobile adverts.)

I could have sketched some schematics, and included some more math, but that would have been rather time consuming for me. Frankly, I didn't know if any reader would be interested in that level of detail.

If you (or another reader) really wants a more thorough (and hopefully more clear) explanation, please reply and let me know, and I'll find time to put one together in the near future.

--

Meanwhile, as to your specific question about line inputs: Line inputs are usually much better able to handle high input levels than are mic inputs.

You would not connect a mixer's XLR outputs to a recorders MIC inputs... you would connect to the recorder's LINE input. That shoud completely eliminate the use of the mic preamps in the recorder.

A mic input is frequently wired directly into a preamp IC, and an IC can be overloaded if the incoming signal level is too high.

In olden days with valve equipment, the line input was frequently connected directly to the "Line level" potentiometer... the rotary control that set the recording gain for line input. Being a passive device (no amplification), a potentiometer won't generate distortion like an IC will; it will work at any level, until the level becomes so high that it actually burns out the potentiometer. (You will notice a "burning electrical smell" when this happens!)

Our new recorders frequently don't even have rotary potentiometers, but rather some sort of solid state digital gain control IC. Therefore, today's Line Inputs are not quite as immune to overload as olden ones. Even so, they are designed to take pretty high levels.

Worst case, if a given mixer has much too much output for the line input on a given recorder, again, you just build a fixed attenuator "pad," in this case using two or three resistors (per channel) and that reduces the level to one that keeps the recorder happy. So, again, it's first a question of knowing the specific mixer and recorder in question, then looking up the specs, and finally calculating the resistor values (if any are needed).

To get back to the original question (sort of) - specifically concerning the Marantz pmd 661...

Is it possible to monitor and control both xlr mic inputs separately?

From everything I've read, it seems like you have to apply the controls to both mic input's together. For example, after looking through the owner's manual online, it seems that if you turn up the gain, it has to be for the mic/line inputs together, without control over each mic separately.

I also wonder about the recording volume... can this be adjusted on a single mic basis?

Yes,
Why don't you download the users manual.

Hi Rick,

I did. But I didn't see anything that indicated I could, for instance, set different record levels for xlr input 1 and input 2.

Can you reference a page in the manual?

As far as I know this has been corrected in the latest firmware, so I don't know if that change has been corrected in the manual. On the H4N I would install the latest firmware and test it out.

Marantz PMD 661 manual. Page 9,

Item 3. REC LEVEL Control
"Turn to adjust the record level when the “Level Cont.” of preset
menu is “Manual”.
The inside control (Right channel) and outside control (Left
channel) turn together, unless you hold one while turning the
other.
The optimum record level is when the level meter goes as close
to 0dB as possible but does not go OVER."

Thanks, Rick!

As far as I know this has been corrected in the latest firmware, so I don't know if that change has been corrected in the manual. On the H4N I would install the latest firmware and test it out.I've just downloaded the latest firmware and the xlr input volumes can be separately adjusted in the H4n...

The D.Mono mode on the Marantz records input 1 to both the left and right channels with the right attenuated 20db, it also offers full manual control of both channels.