Output levels of Sennheiser G3 receiver

[Steve House]

Originally Posted by Rick Reineke

So Steve, are your saying, the EK100 receiver will drive a +4 input adequately? I can't see how. I'm not sure what spec Sennheiser is using for 0dB. Could it be the AF setting of +12dB on the receiver refers to the actual maximum peak output level in dBu or VU? In a +4dB 'real world' situation, program peaks regularly reach and exceed +20dBu.
In any case, I certainly can't get adequate input levels feeding +4dB input, even if sacrificing headroom on the transmitter to get a hotter output at the receiver.
My typical settings are (using a Tram) 'Sensitivity' setting on the transmitter @ -20dB (or occasionally -10dB for a 'low talker' or quiet scene) The receiver's 'AF' is normally set to -12dB, feeding a mic level input. Though I'd prefer to use line level, this works good.

Have you tried setting the receiver output to 0 and connecting it to a prosumer (-10dBv) line level input, then doing all further gain adjustments at the transmitter? You mention "sacrificing headroom on the transmitter." Sennheiser does NOT suggest you allow for ANY headroom on the transmitter - their instructions explicitly say that the audio input control on the transmitter should be set as high as possible so the meter goes to full scale, backed off just enough to prevent the 'overs' LED from illuminating. Remember we're driving a transmitter's modulator here, which works differently from the way a recorder works. You don't get clipping, you get overmodulation if you drive it too hard. You want it to come as close to 100% as you can - the digital recording equivalent would be where you'd want the signal to come up to where it just touches 0dBFS. Can you get normal recording levels for speech with that strategy? If you can, then driving a +4 input shuld be possible by dialing in more 12dB of boost on the receiver output with the same transmitter setup and source.

10/8 ......

Here's direct quotes from Sennheiser's tech support FAQs...

I can't get enough output from my Evolution Wireless, what could be wrong?
The sensitivity adjustment on the transmitter is adjusted too low, it is factory set at "-30 dB". Follow the directions in your owner's manual and readjust.

and...

My wireless system is noisy
Never control mixer board levels with transmitters sensitivity settings. The audio level/volume knob on the back of the receiver should be used for board levels. The sensitivity level of transmitter is set by looking at the receivers audio display. The ideal audio level is 3/4's of the way up the display scale. If the display level peaks every now and then that's good.

[Rick Reineke]

Thanks anyway Steve, but I really don't have a 'problem' with my current setup. I was just relaying my experience for the OP... but I'll try pushing the transmitter levels a little hotter.. though I've 'been-there-done that' and it's resulted in audible distortion. (and it wasn't in the receiver>mixer interface) I'm still skeptical, unless they've changed the gain structure on the G3?

[Tom Morrow]

I got a lot out of Steve's suggestion to really pay attention to the transmitter level meter and not worry about digital clipping.

Everything Steve says makes sense in a controlled environment where the sound source level is completely consistent, such as a professional newscaster doing a remote.

But my experience agrees with the others that trying to set the transmitter for full scale deflection results in clipping; I've experienced tclipping in situations where the microphone was a "plant" taped under a table to capture action taking place around that table, and I had cranked the transmitter gain to account for the distance to the speakers. The clipping light on my SD mixpre went on in those cases, and the sound was distorted.

By the very nature of these devices it's impossible to monitor and adjust gains in real time; the only level setting approach that can be used is to have the soundperson squint at that tiny transmitter meter that has no calibration markings and try to guess how close a given signal is to peaking. And that's typically done once during rehearsal unless you have a soundperson crouching under the table during the shoot riding levels on the speaker's transmitter :-)

Trying to dial in that final 6db on the recording device preamp, as well as transmitter and receiver gains, during that single rehearsal while the transmitter is body-mounted on talent, seems like more work than I can handle.

Since you can't ride the transmitter levels at all during the performance, setting it to peak right at full deflection sounds like a recipe for clipping. And since wireless is used when the action is too dynamic for wired sound, it is expected that there may be more level variation.

It just seems like with wireless it is necessary to leave a lot more headroom on the transmitter than you would if you have the ability to adjust it easily in real time.

So even though it may be technically possible to achieve line level signals under the most controlled conditions, it makes sense to sacrifice the strength of a line level signal for headroom to deal with the unexpected, and that's probably why most people end up with mic level signals.

Steve and everyone, thanks very much for helping clear this up.

[John Willett]

Originally Posted by Steve House

So a full deviation signal into the transmitter produces a consumer line level output on the receiver if the output of the receiver is set at 0. Dial in +12 gain on the receiver output and it should be adequate to drive a pro line level input, perhaps a tad low but still usable, especially if there's some additional gain above unity available on that input..

I think people tend to forget that the transmitter gain and the receiver gain are independent. Any signal that drives the transmitter to full deviation will produce the same output level at the receiver for any given receiver gain setting. Whatever the signal source, adjust the transmitter AF gain to produce full deviation on the meter. You found that a setting of 30 with a +4dBu input did that. A mic plugged into the transmitter would need a different setting at the transmitter to give the same deviation. A consumer CD player yet another setting at the transmitter. A DJ's sound board output yet another setting at the transmitter. But if the transmitter was set in each case to give full deviation with only rare flickers of the 'over' light, you would get exactly the same output coming from the receiver, regardless of the actual level of the source being fed to the transmitter.

So the order of operations to get things set up with proper gain staging would be to first adjust the transmitter gain for full-scale indication on the the transmitter's meter without unduely lighting its 'over' indicator, then adjust the receiver output level to adequately drive whatever input you're sending it to, perhaps needing a combination of the receiver output setting and the input 'trim' setting of the destination device to get it just right. I would expect a 0 on the receiver to be about right for a prosumer camera line level input, values in the low negative range to be right for a mic level input, and +8 or +12 for line levels on pro mixers or cameras. In all cases, fine-tune it with the input trim control on the final destination device. But the transmitter gain has to be set up properly first before you can even think about receiver output level settings.

The perfect answer. ;-)

[Tom Morrow]

Another issue to consider: How good are the preamps in the g3 receiver versus whatever gain is available afterwards. If feeding signal into a DSLR with cheap mic preamps, then you would want to set AF OUT relatively high (perhaps 0), but if you are feeding a sound devices mixer with good preamps, you might want a lower signal so the mixer preamps do the heavy lifting. It's probably also worth considering which device has the best batteries... +12 will probably use up the g3 battery more.

After reading this thread and doing a little testing of my g3's I'm going to try out these rules of thumb and see how they play out in reality:

Transmitter AF: -30 for loudish speakers, -21 for normal speaker, chest mounted, -9 Distant or quiet speaker.

AF OUT: 0 for most cases, -12 feeding SD mixer mic input, +12 if for some reason I really need a line level which is rare for me.

Experimenting with these settings I get strong mic levels and enough headroom so the AF peak light comes on only when the speaker raises their voice to a level close to shouting. If I am in a controlled situation where levels won't vary too much, I might be able to adjust the Transmitter AF 10db or more hotter based on rehearsals.

[Steve House]

Originally Posted by Tom Morrow

....Transmitter AF: -30 for loudish speakers, -21 for normal speaker, chest mounted, -9 Distant or quiet speaker.

AF OUT: 0 for most cases, -12 feeding SD mixer mic input, +12 if for some reason I really need a line level which is rare for me.

Experimenting with these settings I get strong mic levels and enough headroom so the AF peak light comes on only when the speaker raises their voice to a level close to shouting. If I am in a controlled situation where levels won't vary too much, I might be able to adjust the Transmitter AF 10db or more hotter based on rehearsals.

For best S/N you want the transmitter modulated as fully as possible. Unless you know there's going to be shouting and you need to leave room for it, the transmitter intput level should be high enough that in normal speech the meter is full scale but the 'over' indicator stays off except perhaps just barely flicker on the very loudest peaks of the voice. Generally the meter would be pulsing between about 80% and full scale.

A wireless rig is NOT a single single chain of gain stages with the radio portion behaving as if it was an invisible cable. It's actually two fully independent chains, mic/source->transmitter and receiver->mixer/recorder. The setting of the gains in the various stages prior to the transmitter's antenna has no influence on the gain settings of the various stages starting at the receiver's antenna and ending with the recording device, nor vice versa.

One chain of gain staging runs from the mic element or signal source to the transmitter, going through the transmitter's audio circuits and ending at the RF modulator section. It comes to a full stop there. You need to adjust the gain staging of this chain so it modulates the signal fully without going into overmodulation, the transmitter's equivalent of clipping.

The second chain STARTS at the RF demodulator in the receiver. The demodulator is the original source of that signal and It produces a certain level when it receiver a properly modulated signal. On the transmitter side that signal might start out as a +12dBu loud sound off of a sound board's pro line level (+4) output or it might be a -45dBu whisper picked up by a lav capsule planted in the flower arrangment in the middle of the lover's table during a tet a tet, if the transmitter has been adjusted so that each one gives full deviation on its meter you'll get exactly the same level signal coming off of the receiver demodulator. That chain continues through the audio output circuits of the receiver into a mixer or recorder or camcorder's input. You adjust the levels in those stages for optimum performance in that chain.

Each of those two chains is complete in and of itself and the optimum settings on one of them has no bearing on the proper settings for the other.

As for your setting for the SD inputs, I'd experiment to see which works best but starting with setting it to line. Generally circuits work best when they're running about the mddle of their control range. I'd start with the transmitter audio at whatever gives you full deflection on its meter with your test signal, the receiver output at 0, the mixer meter on VU ballistics, the mixer input on line, the mixer fader set on unity, and then play with the mixer trim control to see if you can get speech metering between 0 and +4 on the mixer while the channel trim is in the middle 2/3 of its range. If the receiver is output is too hot drop it down a notch, too low dial it up a notch, and try again, If you can't adjust the trim to get good level on the mixer meter with the input on line without going up to the extreme of the receiver's adjustment range, switch the mixer input to mic level and repeat the process.

[Tom Morrow]

Doh, this morning I shot footage with the transmitter level set to -21 and got very clipped sounding dialog in my headphones. I ended up literally crawling over to the guy being interviewed in the chair while the video was running, checking the transmitter meter, crouching just below the frameline. Not very professional but this wasn't more of a practice shoot so I could get away with it.

I turned the level down to -30 and the clipping went away. Then I realized the likely cause: This was the first time I was using the ME4 cardioid microphone, and it probably had a different output level from the Rode Lavalier that I came up with those rules of thumb on.

So lesson learned: recheck the transmitter sensitivity when switching microphones.

I'll reread this thread when I'm less tired and frustrated.

[Tom Morrow]

Originally Posted by John Willett

The output level is adjusted in the receiver.

The output of the EK 100 is unbalanced on tip and sleeve only (the ring is not connected). It is supplied with two cables: one to mini-jack (tip and ring shorted at the far end so the sound is fed to both channels) and the other to an XLR.

#################
EDIT: Note that the following text has been proven incorrect in later discussion. It's left in place for people who want to follow the thread, but I no longer believe that line and mic are connected to the same thing.
#################

For completeness, I want to reinforce this fact. There is some info floating around the internets that the g3 transmitter has both a line and mic input and that it switches between them based on whether the ring or tip of the locking connector is wired to a signal. This is not true; my original post in this thread was incorrect. You use the input level control not a different connection to switch between line and mic level inputs to the g3 transmitter.

John's statement and my experiments today agree: There is only one input on the g3 transmitter, on the tip and sleeve of its input connector. The ring connector is not connected to anything. I came to this conclusion by using an ohmeter to see that all three sennheiser brand adapters (locking to 1/8", XLR male, and XLR female) are wired with no connection to the ring on the locking connector. Also I see the same signal levels on the transmitter LCD no matter which cable I use to feed a 1k tone to the transmitter.

[Steve House]

Originally Posted by Tom Morrow

For completeness, I want to reinforce this fact. There is some info floating around the internets that the g3 transmitter has both a line and mic input and that it switches between them based on whether the ring or tip of the locking connector is wired to a signal. This is not true; my original post in this thread was incorrect. You use the input level control not a different connection to switch between line and mic level inputs to the g3 transmitter.

....

Look at page 32 in the manual for the SK100G3 bodypack transmitter to see the connector assignments for the transmitter's 3.5 mm input. There are two drawings at the bottom of the page, labelled "mic" and "line." The illustration for a mic-level input signal very clearly shows the mic signal hot (explicitly labelled "mic +") going to the tip, with the ring and sleeve jumpered together to connect both to ground. The illustration for a line-level connection shows just the reverse, signal hot (labelled "line +") connected to ring while tip and sleeve are jumpered together so both go to ground. (Note that these diagrams are in the stand-alone manual for the bodypack transmitter but seem to have been omitted from the more generic manual for the 100G3 sets. Look up the transmitter on the Senn website, download its manual and see for yourself.) For your ohmeter checks you need to be sure you're using the Sennheiser supplied CI-1 (1/4->1/8) instrument input cable or CL-2 (XLR-F->1/8) line input accessory cables and not the cable that comes with the set that's intended to connect the receiver to its destination input. The cable with the XLR-F is the line input cable intended for the transmitter, the one with the XLR-M is the output cable for the receiver and is NOT wired the same. AFAIK, both line input cables are extra cost accessories and don't come in the sets. The CL1 (straight 1/8->right angled 1/8) that comes with the set is also for receiver output, not transmitter input.

The input level control is the gain control for the transmitter's audio stages, set to whatever gives you full modulation. Think of it as a trim control similar to the recording gain on a camera or recorder, applied in order to adjust the transmitter's modulation level after the basic input sensitivity is set to either mic or line by the choice of input connection wiring .

A wireless setup is really two separate but interdependent chains of gain staging and they need to be thought of separately. The first chain is signal source (microphone or line level source) going to the transmitter while the second chain is the receiver to the signal destination. You adjust the first chain so the transmitter is working at its best - best signal to noise and so forth, then you adjust the second chain's levels for optimum levels going to the camera or recorder. You use the transmitter input level adjustments to control the first chain, the receiver output level adjustments in conjunction with the ultimate signal destination's input levels to control the second. Set the transmitter level to give near full-scale deflection on its meter, overs light rarely flickering, while ignoring what's coming from the receiver - once its set leave it alone. Then adjust the receiver output level to give optimum results in your final destination device. DO NOT use the transmitter level control to adjust the receiver's output level even though changing the transmitter control will, in fact, change the receiver output. You always want the tranmitter working at its best - averaging as full a modulation level as possible without risking it going over.

[John Willett]

Originally Posted by Tom Morrow

For completeness, I want to reinforce this fact. There is some info floating around the internets that the g3 transmitter has both a line and mic input and that it switches between them based on whether the ring or tip of the locking connector is wired to a signal. This is not true; my original post in this thread was incorrect. You use the input level control not a different connection to switch between line and mic level inputs to the g3 transmitter.

John's statement and my experiments today agree: There is only one input on the g3 transmitter, on the tip and sleeve of its input connector. The ring connector is not connected to anything. I came to this conclusion by using an ohmeter to see that all three sennheiser brand adapters (locking to 1/8", XLR male, and XLR female) are wired with no connection to the ring on the locking connector. Also I see the same signal levels on the transmitter LCD no matter which cable I use to feed a 1k tone to the transmitter.

Tom - sorry, this is misleading and incorrect.

Read the manual - please.

On the G3 TRANSMITTER:

The microphone is connected to the tip and sleeve and the ring is shorted to sleeve. This puts out a plug-in-power voltage to power a tie mic.

A line level input is connected to the ring and sleeve and the tip is shorted to the sleeve.

This is clearly stated in the manual.


On the G3 Camera RECEIVER:

The output is unbalanced and is connected to tip and sleeve only.

If you have a 2000 series or 500 series G2 receiver, then the output is balanced: +ve on tip, -ve on ring and screen on sleeve.


Sennheiser do several adaptor cables. The ones with a male XLR are for the receiver. There are two versions: one wired unbalanced for the 100 series and the other wired balanced for the 2000 / 500-G2 series.

The ones with a female XLR are for the transmitter. There is one that is for a microphone and is connected to the tip and has a blocking capacitor inside the XLR, the other is for line level and is wired to the ring.

[Tom Morrow]

Thanks Steve and John, it's clear that I spoke too fast when I declared it to be a fact that the transmitter doesn't have separate line and mic inputs. My apologies for muddling things, and I'm going back right now and redoing my experiments... stay tuned.

[Tom Morrow]

A little aside: One snippet from Sennheiser's animated manual

Sennheiser evolution wireless G3 100

In the "Adjusting sensitivity" section Sennheiser says the transmitter sensitivity is optimally adjusted if the level display deflects as much as possible, and the peak display occasionally lights up for a short time.

Just like Steve said!

The idea of hitting full scale scares me, but I'm going to guess they have some safety margin above where the Peak indicator lights so that one doesn't have to run out of clean gain right at the Peak indicator.

[Bob Willis]

Thanks for the link Tom.

[Tom Morrow]

Indeed I now find that my cable (CL2 I believe) is wired as described in John's post, with
1/8" locking sleeve tied to tip and XLR-F pins 1, 3.
1/8" locking ring to XLR-F pin 2

I just verified that all three of the lav mics I have were wired with the sleeve and ring tied together.

My printed and online manuals don't have any information about the line/mic connections, but I did find an online manual that has the diagram of the separate line/mic connections, the one that John referred to, on page 32:
http://www.sennheiser.com/sennheiser/products.nsf/resources/C12573B10069CA4AC12574E300453716/$File/SK_100_US_INT.pdf

I did some searching around online, and I was able to find these cables for the g3s (not counting the 1/4" instrument cables):

• The receiver (EK100) to male XLR cable is called the CL100 and comes with the kit
  (my kit cable has a blue XLR-M body, while the CL100 sold separately has a black XLR-M body).
• The receiver (EK100) to male right angle 1/8" cable is called the CL1-N and comes with the kit.
• The transmitter(SK100) to female XLR cable wired for Line not Mic, is called the CL2
  (with black XLR-F body and silver locking 1/8" connector)
• The transmitter(SK100) to female XLR cable wired for Mic not Line, is called the CM1 and it incorporates a DC blocking capacitor to protect the mic diaphragm
  (with black XLR-F body and black locking 1/8" connector)

I would like to locate a cable for inputting line level 1/8" signals into the transmitter for when I want to soundcheck my transmitter by feeding it an iphone signal. Now that I know that the CL1-N cable shorts the right and left channels together I'm leary of connecting it directly to the iphone; I want a cable that either sums(monos) the R+L signal or just takes one or the other. Also,the CL1-N which uses the tip for the signal would end up wiring to the mic not line connection on the transmitter. And horrors it probably doesn't block plug in power.

Thinking about this now, I suppose I already have what I need to put together that cable. I just take my Sescom SES-IPOD-XLRM06 cable and plug the 1/8" end into the iphone. The right (or left, I choose) male XLR of the Sescom then plugs into the female XLR on the CL2, which of course plugs into line connection on the transmitter.

Thanks everyone (esp John and Steve) for being a good sport and filling in useful info.

[John Willett]

Originally Posted by Tom Morrow

A little aside: One snippet from Sennheiser's animated manual

Sennheiser evolution wireless G3 100

In the "Adjusting sensitivity" section Sennheiser says the transmitter sensitivity is optimally adjusted if the level display deflects as much as possible, and the peak display occasionally lights up for a short time.

Just like Steve said!

The idea of hitting full scale scares me, but I'm going to guess they have some safety margin above where the Peak indicator lights so that one doesn't have to run out of clean gain right at the Peak indicator.

With a transmitter you want to have as high an output as possible to reduce noise, but not so loud that you distort.