the h4n lets you set different gain levels on each channel

Thanks, @soundgh2. So, if I bought that item, would I set it up as illustrated in the attached diagram? If so, what level of attenuator would you recommend?

I don't want to lower levels in post because the whole point is to avoid losing very high or low audio levels while recording. If I record L and R at the same level, then if there's a loud crash, it will be distorted regardless of whether I lower the levels in post. If I have an attenuator on one of the channels, I would be more likely to capture that loud crash, while the normal sounds (eg. voices) are on the un-attenuated channel.

Another example is, let's say I put a lav mic on the groom at a wedding. Wouldn't it make sense to attenuate one of the two channels of his mic? In post, I would use the attenuated channel for his loud voice, and I would use the unattenuated channel to capture the bride's soft voice. Does this make sense? Or should I just stick with raising the levels in post on the bride's voice and lowering the levels on the groom's voice?

For me, it's a waste to record two channels of audio which are basically the same, so I'm wondering if I can make more use of having two channels.

@DrDave, so I would lose quality with the attenuator? I thought that it only decreased volume (as if you were decreasing the levels on your recorder), not quality. Thanks.

Thanks to all for their replies. I guess there is no good way to accomplish this. I may just have to save up for one of those recorders that records a lower level track in addition to the normal level track. Such a shame we can't adjust left and right levels independently. I bet very few people value the stereo affect on the GH2 or most other cameras, because it has very little value. If you are trying to create quality stereo sound you should have one mic to the left of the "stage" and one mic to the right. Might as well have mono sound for 99% of what we do with the GH2 audio.

@Peter123456 What's the problem? If you want to insure you have enough headroom, just make or buy a single-channel -6db attenuator as others have suggested.

@Trevmar, thanks for the info. I will definitely look into that audio meter. Can you recommend a good book on sound recording?

@LPowell, I was worried that the attenuator would affect sound quality, but I think I will give it a spin anyway. Can you please confirm that my diagram from my first of two posts from October 1 is correct (assuming I get the single channel attenuator)?

Thanks.

A camera has nowhere near 16 bits audio. You can't even get 16 bits in a CD recorder. Just look at the waveforms--there's tons of empty space. You can dither the 16th bit by adding low level noise, but you still won't get the full resolution. You can "fill" the unused bits with with information using HDCD encoding, but you can't do that on a camera, and no one does it anymore since you can record 24 bit on a Zoom.

Most Panasonic cams have compressed audio. It decodes to something that looks like higher resolution, but it isn't. Since it is compressed, you can't push it in post and it almost always simply throws away the low sounds and the high sounds. Many Olly's have 16 bit pcm, which works out to 14 bit at best. Olly 16 bit sounds decent, but it isn't 24 bit like a zoom.

And for stereo sound, the best sound comes from a matched set of stereo microphones, where the capsules are virtually identical, and the levels are exactly the same. No need to attenuate. Use an spaced AB or an ORTF setup. If you want to reduce the volume, do it in post.

Also, with an attenuator there is indeed very little degradation of the sound going into the converter, but once it hits the converter you of course lose resolution. However, if it sounds good, go for it.

Rode mic noise figures: Rodes are generally way, way, way quieter than 20dBa. And NT1A (cheap) has a self noise figure of 5dBA. That doesn't make it better, just quieter. 20dBa is too noisy.

99.9 percent of audio is microphone placement. Recording at the correct level is important, but using simple math we can see that 1 bit=6dB. So if we set the gain too low, 12 dB too low, and record at 24 bit, we are still at 22 bit, which is still totally fine. Place the mic wrong, and it will just sound bad.

There is no reason to buy a sound meter. A digital bit meter can be useful, and all the meters you need are included in RME if you need precise, reliable metering of all aspects of audio. An inexpensive meter will not meter accurately, and may miss spikes in fast moving transients.

Adding 40 dB in post: at 16 bit you are basically getting 14 bit if you set the levels correctly. Set them 40 dB too low and you lose 6 or 7 more bits. IMHO that's too much for 16 bit, and even at 24 bit you are then running into preamp junk that kicks in at low levels. I would only add 40 dB in case of epic gain knob failure.

Books on recording: the Classic is the Stereo Soundbook http://www.soundonsound.com/sos/nov09/articles/stereosoundbook.htm but it doesn't cover everything. A good intro is at the DPA online website "microphone university" http://www.dpamicrophones.com/en/mic-university.aspx

Basically, the online stuff covers everything if you look around. Why no great book, only good book? There's too many kinds of audio. Pop isn't classical isn't video, and so on. I do recommend the school at Detmold, but that is a ways away. Unless you live there, of course. http://en.wikipedia.org/wiki/Hochschule_f%C3%BCr_Musik_Detmold

Headroom: the headroom is not independent of the source or the mic placement. Setting the gain to an arbitrary level like "37" will simply give you three results: too high, too low or just right. Recording samples and looking at the waveforms will tell you quite a bit, and even cheap DAWs like Samplitude have FF analysis and show precise levels.

Trevmar, it's true that a gain setting of 37 on the Zoom H1 produces the lowest internal noise. Your mistake is that you did not account for the other sources of noise in the system. Using a gain setting that is too low will result in a recording with lower effective resolution (bits per sample). After boosting the gain in post, you'll end up with more quantization noise than if you had set the gain correctly on the H1.

Basically on the Zoom H1, 20-100 is the range of useful gain settings, and 37-100 is the range with the lowest equivalent input noise. If your choice is between a setting of 35 antd 37, 37 is almost certainly the better choice. But if you have a lot of clipping at 37, a lower setting is almost certainly better.

Having 24 bits of resolution gives nice headroom, but you'd need a recorder with much more than 24 bits to be able to just set the gain and forget it.

Good idea, @Rambo, but what about the officiant? Did your uni-directional capture his voice as well?

Hi all, just an update. I bought the adjustable attenuated cable from soundprofessionals, but realized it would probably require mono to stereo adapters, and I just got annoyed with all the connections which would probably degrade the sound quality. I think it's more trouble than it's worth unless you could get/build a mono 1/8 inch attenuator. I am just sticking with a normal setup for now.

I want to attenuate one of the channels coming out of the tape out on a Sound Devices MixPre. The tape out has a 2.1k ohm output impedance. What resistors should I use to attenuate just one of the channels to -12db? I'm having a hard time wrapping my brain around the appropriate values and hope some of you have some more experience in this than I do. Thanks.