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Old August 23rd, 2006, 10:21 PM   #1
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Line level sennG2 to beachtek to XL1

Using a sennheiser G2, a beachtek XLR adapterand an xl1 I have several ways to lower the level of the audio. I can

1. set the sensitivity on the g2 mic to -30db
2. lower the output of the g2 receiver
3. switch the beachtek to line in
4. turn down the output on the beachtek
5. set attenuation on the XL1
6. lower the levels on the XL1

Can anyone explain what the difference is between all these? or the best way to lower the audio level? I recently recorded a very hot signal from a mixer - I set the g2 transmitter to -30db but it was still peaking quite frequently but the recorded audio sounds great. I would have thought that there would have been some distortion from the g2 transmitter being overloaded, even though the camera levels looked fine.
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Old August 24th, 2006, 08:23 AM   #2
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You may want to buy an additional attenuator to go between a line-level source and your transmitter if your transmitter input can't be set any lower. If the distortion occurs there, then nothing else in the chain will help remove it. The appropriate attenuator will depend on the type of output connector from the mixer, as well as how hot it is. There are a variety of ways to do this depending on the mixer and you may not need much additional attenuation here, but a device with switchable settings is handy.
Setting the BeachTek to Line creates a substantial drop. It's usually better with the XL-1 to use the MicAtt setting on the camera and then feed in a hot Mic-level signal. So keep the Receiver output at hot mic level, the BeachTek at Mic with the control at 9 or 10. Then adjust your camera levels appropriately after engaging the MicAtt switch. This is usually somewhere between 10 o'clock and 1 o'clock on the dial. If you have to go below 10 o'clock on the camera to get a safe level, then you should probably lower either the BeachTek control one click or the Receiver output one level.
Remember that most of the BeachTeks (except the DXA-8 and 10) are passive, so they should be run with the control at 8 to 10. Also if using MONO mode on a passive BeachTek, the "off-side" control also affects the signal to some degree. Keep it all the way up or use it as a trim control. It will affect the signal less per click stop than the on-side control does. Don't forget that some of the BeachTek's inputs are correct when you're looking at the connector side, but that's backwards if you're only looking at the control side. It's easy to plug in incorrectly if you're in a hurry. Some older BeachTeks, like my original DXA-6, are also out of phase if you're using two matched sources. So that's another catch to listen for.
Most importantly, keep listening to the camera. That's the best way to catch distortion, although it may take a headphone amp since the camera output jack is often very weak.
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Old August 24th, 2006, 09:54 AM   #3
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thanks Jay

I guess to put an attenuator between the mixer and the g2 transmitter I would need (ideally) an attenuator with 1/8" or rca in and 1/8" out- do they make such a thing?

also anyone recommend good isolation headphones - the sony 7506 I use are not so useful in loud settings
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Old August 24th, 2006, 10:35 AM   #4
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What do you have the receiver set at? You shouldn't need anything else in that set up it should work fine as it is. It's just a matter of tweaking it to work for you. You said it recorded fine, are you sure your looking at the right meters? Clipped audio is cliped audio anywhere in the chain and there is no getting it back. If it recorded fine it's not clipping.
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Old August 24th, 2006, 12:39 PM   #5
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The beauty of analog FM (as opposed to today's digital which is, of course, beautiful in its own ways) is that it doesn't clip in brick wall fashion if the modulator is designed properly. I used to work at an FM broadcast station and we were allowed 75 kHz peak deviation. If this was reached a light hanging over the console blinked to tell us to lower the level which we did because if the light blinked too much we knew the FCC would be around. But the signal was not distorted when this happened. That's why you are still getting good sound even though your transmitter is indicating peaks fairly frequently. Apparently the G2 is linear well past the peak deviation indication.

The higher the deviation, up to the limit where distortion occurs, the better the received signal to noise ratio (there are, of course, practical limits to this) so if the sound is good at the output of the receiver I wouldn't worry about it. I don't think the FCC truck will be out looking for you as the power from these sets is so low and you don't need to be concerned about breaking anything.

[Mispelling corrected]

Last edited by A. J. deLange; August 24th, 2006 at 04:30 PM.
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Old August 24th, 2006, 02:47 PM   #6
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We really need to talk specifics here. Which G2 transmitter are you using? There are several similar models with different inputs.
Are you using the specific Sennheiser Line-In Cable or just a regular 1/8-inch cable?
What mixer did you connect with and which output was used?
It's very true that transmitters are designed to be run with a hot input in order to get the best signal to noise ratio, that's why you were ok with the transmitter input meter showing alot of peaking. But it's hard to know how much headroom you had left without pushing it further in a test. Since the transmitter is usually the least accessible piece of your chain once the real show begins, not having any room for error there is not a good thing. You were safe this time since you didn't get any distortion but a different mixer output could be much hotter, and then you could need additional attenuation before the transmitter input. There are RCA consumer line-level to 1/8-inch mini mic-level attenuators, but depending on the mixer you're using that might not be the best solution.
It's also been discussed here many times, the XL-1's meters won't indicate if you're clipping the audio input with too hot a signal. The meters show the level of signal going to tape, not whether you've already clipped the signal at the camera input. You have to listen closely to hear this, especially if the transmitter is starting to distort, because that will be more subtle.
The 7506 headphones are good phones, but using a headphone amp on the XL-1 may help in loud environments. In-ear monitors are also a good solution and allow you to monitor correctly at a lower volume, but good ones aren't cheap.
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Old August 24th, 2006, 06:57 PM   #7
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jerry - the af output on the receiver is set to -12db to match the beachtek which is set to mic in.

AJ - I amconcerned that I may not always be so lucky.

Jay I am using the senn ew100 setup the transmitter is the ek100. I'm just using a regular rca to 1/8" cable - I didn't know there was a specific line-in cable - that sounds perfect - I see them online for both 1/4" and xlr - do they have attenuation built in? - thanks for the tip I will check it out tomorrow

I 100% agree with the need for more attenuation at the transmitter but have not been able to find an attenuator that works with rca or 1/8". B&H don't have any such thing. radio shack have an 2 1/8" attenuating cables but they say -90db on one and -60db on the other. Both of them just look like regular 1/8" cables.

As to which mixer well that changes gig to gig - whatever the Dj has. I normally try to use the record out on the assumption that the record out levels will not be affected as the DJ raises and lowers the volume.
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Old August 25th, 2006, 03:07 AM   #8
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Quote:
Originally Posted by Doug Bennett
....

As to which mixer well that changes gig to gig - whatever the Dj has. I normally try to use the record out on the assumption that the record out levels will not be affected as the DJ raises and lowers the volume.
That actually may not generally be the case. On Mackie Compact mixers, for example, the "tape out" and "mono out" jacks are tapped off of the main mix bus post-fader, meaning the levels on those terminals will go up and down as the operator rides the main output controls. On those mixers, to get outputs whose levels are set independent of the main mix level, you need to look to one of the Auxillary bus outputs, Submix bus outputs, or the individual channel strip's Direct outs. While I'm not familiar with DJ specific equipment, I'd expect many boards you'll encounter to be similar in that regard. If you can touch bases with the DJ a few days before the gig and find out of what make and model of board he'll be using, a quick check of the manufacurer's web site will often turn up an owner's manual that will tell you fo sure.
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Old August 25th, 2006, 09:17 AM   #9
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I don't believe the Sennheiser cables have built-in attenuation, they simply connect to the Ring segment of the input jack which is intended for Line-level signals. The Mic-level signals are input on the Tip segment of the jack.
The XLR cable probably doesn't use pin 3, which gives it a 6db attenuation when hooked to a standard balanced line out connector. But that's just a guess on my part. In addition, many inexpensive mixers have impedence balanced outputs but the entire signal is carried just on pin 2. In that case you would not get any attenuation using an adapter cable that has no pin 3 connection.
The Sennheiser manual states you can input up to 2.4Vrms on the Line-level connection. The impedence is 1 megaohm.
Fred can probably give us a better real-world idea of how that compares with line-level signals you're likely to run into.
The mic input is listed as 1.8Vrms maximum at 10 kiliohms impedence.
You have the menu adjustments for 30db of attenuation.
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Old August 25th, 2006, 10:41 AM   #10
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Given that the input impedance to the transmitter is high (1 megohm qualifies) and the output impedance from the source is low (and most are) you can easily make up attenuators of your own with two resistors. For example if you connect a 47 Kilohm (47K) resistor between the tip and sleeve of the transmitter input plug and then connect another 47K resistor between the center conductor of the cable and the tip connection on the plug (thus also connecting it to one end of the first resistor) you will have approximately 6 dB of attenuation. If the second resistor is 100 K you will have about 10 dB of attenuation and if it is 470K about 20.
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Old August 25th, 2006, 12:19 PM   #11
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I just spoke with a tech at sennheiser and he said that as long as the receiver not overload the input to the camera, I don't need to worry too much about the transmitter being overlaoded by the mixer. Sounds strenge - but that is what happened for me last week
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Old August 25th, 2006, 04:42 PM   #12
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I think if you are using a Sennheiser line-input cable connected to a mild line-level output from a mixer then you would be pretty safe as the tech said.
But if you're using an ordinary cable that connects to the mic-level conductor of the jack, and you connect to a full +4db output from a mixer, then 30db of attenuation in the menu isn't going to be enough.
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Old August 25th, 2006, 06:26 PM   #13
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Quote:
Originally Posted by Doug Bennett
I just spoke with a tech at sennheiser and he said that as long as the receiver not overload the input to the camera, I don't need to worry too much about the transmitter being overlaoded by the mixer. Sounds strenge - but that is what happened for me last week
Not strange at all if the design is good and apparently it is. I'll bet these guys have a "Dicke Fix" or similar protective circuitry at the input. This effectively puts a short across the sensitive components if the input level gets to high.
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