If you have a soldering iron, you can build your own:
http://www.uneeda-audio.com/pads/

My camera Sony Z1's has separate level controls for the two audio channels (stereo is a consumer term) so all I need is an XLR splitter and adjust the second channel to peak about 6db lower than the first.

I think you're looking to record a "safety track" in case the main input is too hot, right?
This can easily be accomplished with a panning mixer between the mic and recorder, but experienced pros just record one track at conservative levels.

In other words, the input gains on the recorder are preset so that no peaks can possibly exceed -4 to -6 dBFS. Even if the actual program does not exceed -12dB you are still on safe ground with a relatively quiet system.

If the program levels are too low, of course the result will be noise or compromised bit depth in extreme cases. But the "sweet spot" between about -3dB to -15dB is easy enough to hit when one is familiar with one's own equipment.

And the conservative approach to live recording beats the heck out of dealing with flat-top recordings in post, every time.

If you're handy with a soldering iron then you could try making something like this:



Put it in a little metal box for shielding with a 1/8" mono input jack and a 1/8" stereo output jack. The output's left channel will receive the full level signal while the right channel will get approximately 1/4 the level. The 2200 and 710 ohm resistors are appropriate for a high impedance mic. If the mic is low impedance then 440 and 110 ohm would be a better match. If you really want to get creative you could replace the two resistors with an audio-taper pot and have a variable right channel level.

Note that if your mic is electret then it's power source should come before the input (possibly a battery in the mic) of this circuit rather than being driven by the recorder, which would most likely be the case with your setup. I wouldn't guarantee that this circuit would pass phantom power from the recorder very well.

I would be inclined to use a t-pad in an unbalanced mic circuit or an h-pad in a balanced circuit. Of course one needs to know the input and output impedances.
I did a few of these to adapt headsets to spec for the Clearcom buss. Best to build the pad right into the mic connector if you can.

Thanks. I have something to look at now. And yes, this is in order to record a "safety" track in case the main gets too hot.

Happy New Year.

Chienworks idea looks very good to me, if you're very handy with a soldering iron and used the smallest resistors available you could probably fit it into a plug or even one part in a line socket and another in the plug, just to keep the amount of boxes you have to lug around manageable

My only concern is by how much you find yourself clipping, perhaps a bit more attenuation would be in order.

Bob.

I've fit stuff like that into a 1/4" / 6.35mm plug barrel easily enough, for various values of "easy". However, i'm pretty sure that all the connectors on the minidisc recorder are 1/8" 3.175mm and it would be extremely difficult to work inside that space. Of course, one could build it inside a larger plug and then use a 1/4" to 1/8" adapter after it. This would however add a lot of solid inflexible mass to the poor little input jack on the recorder and put you in a lot of risk of damaging it should it get bumped.

A nice compromise might might be to build the adapter as i specified, but with a short cable and male plug on the output instead of a jack. This would avoid the need for a separate male-to-male cable to connect it to the recorder. It would make it a little less general though and more specific to this particular application.

A., back in my analog recording days i've done something similar when making a mono recording, but i usually have a lot more equipment with me. I'll set the mixer gain on the mic to avoid clipping even on the loudest peaks. Then i patch that mic input to two buses and set the level rather high on one and rather low on the other. Then i send one bus to the left output and the other to the right output and record that on stereo medium. The left channel generally gets a better S/N ratio while the right avoids distortion.

Now that all my recording is straight to digital i'm not so concerned anymore. The mixer and A/D converter both have a better than 95db S/N ratio while my mics achieve about 75db or better. I set the levels to avoid distortion on the peaks and don't worry about the rest of the material ending up around -30. Correct in post with a little noise reduction and it's all good. Of course, i'll record some quiet room tone beforehand to have a sample for the noise reduction to work on.

Um, if originally recording to minidisc and 'too hot', the damage is likely already done, and all you'll be transferring to Vegas is a lower-level-but-still clipped track.


If recording directly into Vegas, and there is no pre-AD 'real' mic level control, then a 10dB pad in line with the mic on one channel would be the story.

geoff

Geoff, normally I actually end up with a fairly low gain, it is just sometimes I end up misjudging the needed gain a bit, even when trying to be conservative, though I hadn't really anticipated the "enthusiasm" of the stand up comedian, once he got started :)

As you said, once recorded "to hot", the damage is done. Luckily SoundForge's clip restoration did manage to save me, this time.

As the current setup only records to the left channel, I wanted to use the right for the lower level, as a safety option.

The Minidisc in question (Sony MZ-RH1) is actually a very good recorder, where even very low levels are clean of noise. I don't recall its specified S/N ratio, but if [url=http://www.avisoft.com/recordertests.htm] is to be believed, it should be about -122dB. And it is a bit smaller than most wireless transmitters the speaker would have to wear instead.

"I don't recall its specified S/N ratio, but if www.avisoft.com/recordertests.htm is to be believed, it should be about -122dB."

Not quite, by a big margin. 122dB is around the theoretical limit for a 600 ohm input so I just had to check that out.

The equivalent noise is -124dBu (A). The input clips at -64dBu so the dynamic range at Max Gain is 61dB.
61dB S/N is OK but that's at just under the onset of clipping. If you leave yourself 10 dB of headroom your S/N ratio drops 10dB which is probably OK as I doubt the venue is all that quiet. I would be starting to get a bit nervous about much more headroom than that though.

Bob.

I [i[wish] my preamps had a -122dB noise floor. Going through the PC inputs, a noise floor of -48dBm is considered pretty good. Even my external Presonus - Firewire box is only quiet to -90dBm.

OTOH - the million-dollar studios can afford gear with a noise floor so low that it's below any consumer's ability to detect, let alone hear.

Geoff, we're talking about attenuation between the mic and the recorder, pre-digitization.

Thanks Bob.

I think I understood some of that.
(I flunked Analogue electronics at University. Twice.)

But it explains the insane Signal/noise level of -122 dB, which surprised me when I first saw it.

Cheers
Asbjørn

> Steve Mann "My camera Sony Z1's has separate level controls for the two audio channels (stereo is a consumer term) so all I need is an XLR splitter and adjust the second channel to peak about 6db lower than the first."

Actually... if you have a Sony HVR-Z1 all you need to do is go into the AUDIO settings and change AUDIO MONI --> CH1+CH2 and it will record the XLR mic on channel 1 to channel 2 as well. Then just set the channel 2 volume 6dB lower and you have a safety copy on channel 2. No splitter needed. I shoot like this all the time.

~jr

... in which case the alternative pad option suggested.

But this may be difficult in practice if the recorder mic input is unbalanced with a DC electret powering voltage. as common for such devices....

geoff