12 bit & 16 bit - Noticeable quality difference?
 

I have never recorded in 12 bit audio with the XL-1 and want to know if there is a noticeable difference in 12 bit and 16 bit audio by someone who specializes in audio. I did plug a mic into my camera while in 12 bit and monitored with headphones and it sounded just as full and clear as 16 bit. Also, I can understand why audio has to be 12 bit in order to be able to provide ST 1 & ST 2 (adding two channels) in the menu but why is it an option for just ST-1 too? Who would choose supposed lower quality for stereo sound when they could just use 16 bit stereo? In other words, other than different bit rates, what is the difference between 16 bit stereo and 12 bit stereo. You're not saving on tape usage (space) so what's the point of using 12 bit stereo.

Oops. I just got this message from Don Palomaki:

"4-channel is 12-bit and sampled at 32 kHz (roughly FM broadcast
quality potential with a ~15 kHz upper frequency limit) while
2-channel is commopnly 16-bit and samples at 48 kHz (with an ~22 kHz
upper frequency limit, which could be better than CD quality).
However, most epeople will not hear the difference due to limitations
of microphones, preamp and venue noise floor, and limitations of
typical playback systems, especially with dialog."

Note that some DV camcorders default 2-channel recording at 12-bit, 32 kHz sample rate. User had to manually select 16-bit mode if they wanted to use it.

I believe that the discontinued VX1000 was one example. Reason was probably to allow dubbing to the second channels later. A seldom used feature in this day of low cost NLE systms.

As I understand it, the 12-bit audio mode uses some compression to obtain about the same dynamic range of 16-bit. Worth noting that the Stereo HiFi digital audio (PCM) channels on Sony's Hi8 system used something like 10-bit recording.

Recording ST1 in 12bit now allows you to overdub narration or commentary to ST2 later. That is why your camera allows you the option of just recording 2 channel @ 12bit.

Thanks Stephen. How would you go back and record audio on those additional channels later without recording over the original audio and video? I guess that recording in 12 bit with 3-4 channels could allow you to record notes for documentation, commentary or even language translation in real time as the native language was being recorded.

Okay, I just thought of this after writing the above. I guess using an audio dub feature on the camera or deck would be the answer to preserving the original content. I have just never seen the need to do this because of NLEs.

Per our sidebar e-mail exchanges:

The audio rates used are based on the DV specification and the bandwidth allocated on the tape for audio. 4 channels at 12-bit and 32 kHz equals the data rate of 2 channels at 16-bit and 48 kHz.

The DV spec was probably finalized back in the early to mid 1990s, when the 80486 chip ruled and 200 megabytes was considered a huge hard drive. That is to say when linear editing was the norm and before the prospect of meaningful home NLE was a reality.

Note also that the DV spec also provides for a 16-bit, 44.1 kHz audio
(same as audio CD) but to my knowledge it has notr been used in camcorders as a record option, although it is supported for playback in the XL1 (and many other DV devices).

So what is the better frequency to record audio in 12bit or 16 bit? I want to be able to add voice overs during editing. I am using the on board mic provided on the XL1s and will be adding wireless at a later date! Thanks,

If you want to add the additional audio to the SAME TAPE at a later time, use 12-bit. Otherwise you are probably better off these days to use 16-bit audio and add the additional audio in post.

Note that some NLE have difficulty with 4-channel audio.

So if I use 16 bit I can add audio within Adobe as a wav or midi file? Thanks for being patient with me Don!

Yes. You can add additional audio tracks in most NLE programs, including Premiere. And you can use the audio tools in the NLE to adjust levels, left-right balance, etc.

I'd stay with 16 bit for your original camera recording, because most NLE systems default to that setting. These same NLE's support a lot of other audio formats, often automatically making the necessary conversions upon import. Also, most NLE's allow for direct voice-over recording, anyway.

The decision is, of course, yours. Sticking to default settings will make your editing tasks easier. It is one of those natural by-products of the editing process. I'm sure that is why Shiner Beer has a banner ad at the top of page I am currently using as I reply.

Now if I add my Sennheiser wireless mics to the stock mic on my Canon XL1 I can still record in 16 bit, or do I need to switch it back to 12 bit st-1 and st-2

If you want to record from 4 channels (two wireless and the stock stereo mic) you have to use 12-bit mode with ST-1 and ST-2. If you want 16-bit recording, you will need to mix the four channels of sources down to two channels using an external mixer, and that may require some adapters for the XL standard mic (if you intend to use it) to ensure it gets power as swell as coupling the signal to your mixer.

Ok, I do mean to be stupid here but I want to be sue I am doing this right... I have the MA-100, stock XL1S Mic, and a Sennheiser wireless mic, I have the MA-100 hooked up to the wireless recevier and so i set the audio to 12 bit st1 and st2, and the stock mic will record on one channel, and the wireless will record on the other. Correct?

Nope, in the scenario you describe, the on camera mic will record onto channels 1 & 2. The wireless would be recording on channel 3 and channel 4 would be empty.

-gb-

So what is my best bet than? still 16bit? This is confusing I am sorry!

What end result are you trying to achieve with your sound? What is the program material, what is the end product? Can your NLE cope with 4-channel sound? Those will drive the best option for your audio recording.

To use both a wireless and the stock mic at the same time, connect the MA-100 to the Audio 2 jacks on the side of the handle, and its power cord to the 5 VDC jack on the back. Use the 12-bit - ST-1/ST-2 mode, set the Audio 2 input to MIC ATT for starters. Keep the Audio 1 input switch set to MIC (or mic ATT as necessary). Connect the wireless to the MA-100 using a balanced output. (Alternatively you could connect the wireless directly to the Audio-2 input if you like.)

You should get the wireless on one of the ST-2 channels depending on where you connected it to the MA-100. Don't forget to adjust the metering and head phone monitoring to the source of interest when shooting.

That is what I am looking for, all I want to do is to be able to put a wireless mic on the hunter, and have the stock mic to pick up surrounding noise, like the animal moving, birds chirping and so on. I am using Premiere Pro 1.5 so it should be able to handle the audio, shouldn't it? I will hook it up and give it a shot and will let you know how it works! Thanks!!!
Jeff

Don, what is mic att? and when I plug in my headphones to listen to the incoming audio, will I be able to pick up the onboard and the wireless at the same time or will I need to make some sort of modification? Thanks for all the help, if you ever get around Iowa I will buy you dinner! Oh, also when I go to import into Adobe Premiere Pro 1.5 will this capture all of the audio I have recorded, or will I have to purchase scenalyzer?

You're creating alot of extra work by using the on-camera mic in the mix. I would use a self powered shotgun mic for natural sound on one channel and the hunter on the other through the MA-100/200, then you will only need to use two channels at 16 bit. Premiere can easily seperate these channels in the timeline.

That is mic attenuation and it gives you more headroom for sound that would ordinarily be off the chart.

The MIC ATT setting reduces the sensitivity of the input by 20 dB compared to the MIC setting. Use it to avoid distortion with high output mics and loud venues, and perhaps to manage AGC gain pumping when using AGC. Use good headphones to judge when to use it, at least until you get a feel for how it works with your mics and venues.

The perhaps major benefit of using the on camera mic for ambient sound in 4-channel mode is your ambient sound will be stereo, if you want that effect.

Alright! Got everything hooked up and it seems to be working ok! However, is there only supposed to be sound in one earphone when I listen to the wireless mics? I have everything set up as directed and when I monitor ST-2 I only get a response in one channel and in one side of the earphones? Also the mic sound is soft but the channel is going over 12db on the monitor. Any ideas?

If you're only recording w/ the wireless to one channel, then you'll only hear one channel--left if track 3, right if track 4. This is completely normal. You can double the track in post-production so that it will come out of both speakers.

As for your second question, I'm assuming that the mic output seems to sound lower because you're only hearing it in one ear. Definitely set your level based on what you're seeing on the meter.

Another thing when using 3 to 4 channels is that you have to hit the monitor button several times to cycle the display to check levels for channel 1 and 2, then 3 and 4. It can get real confusing.

As to how loud the earphones sound, some brands/models of headphones are not very efficient and will not sound very loud, even if the headphone volume control is set to max, with normally recorded material.. You need to be sure your headphones are reasonably well matched to the output of the XL1 headphone jack.

I have a set of Sennheiser headphones and the volume jacked up on the camera. I did go into the transmitter settings and set the sensitivety setting to -20db and it seems to sound much better. Should I leave the two selector switches under the white flap turned to auto for ST1 and ST2, or manual and control the input myself? I do notice on the audio monitor on the camera that the bars are going above 12 is that acceptable? The normal range is well below 12 but if you cough, or raise your voice than it goes it significantly but the Senn Receiver does not peg out only on the audio monitor on the camera. Guess I can run a test recording and see how it sounds on playback. Oh, also, is there a certain freq I should be setting to? I am just using Bank 1... Thanks alot for the input everyone, you are making this alot easier!

James, can a self powered mic be mounted to the camera where the stock mic is mounted? And if so, what mic do you recommend? Also what do you mean by self powered, batteries in the mic itself? Thanks,

-20 dB is usually set on the camera, not the source. The sound guys send tone from their mixers and set the level on the camera at -20 dB as a constant. They actually ride the levels of all of the mics with their own mixer that is attached to the camera by cable or wireless transmitter. If you ever get to work with a sound guy, you will appreciate them alot more and wonder how you ever worked without them.

When monitoring audio yourself, 12 is where the meters need to stay or be slightly below. It is sometimes called the unity mark or level. When setting levels for speakers, have them talk as usual to get an idea of their voices average level. It's something you'll just have to monitor the whole time if you don't have a sound guy.

I don't know about the models after the XL-1 but it doesn't provide phantom power so your mic has to have its own power or circuit to provide sound through the MA-100/200.

James. there is an actual sensitivety setting on the Sennheiser transmitter that can be set to -10db, -20 db, or -30db depending on the amount of ambient noise or background noise. Is there an output setting on the Sennheiser Receiver to control the amount of input being sent to the camera or how do I control the over modulation that seems to be happening on the camera meter? Do you understand my question? Thanks,

The question is, do you understand? I don't know anything about the wireless system you have. There might be a set screw somewhere to adjust the receiver's levels. I just said in post #27 that levels are usually set on the camera. Just have your on camera person speak as he normally would for about 5-10 seconds and set a level on the camera. If he's going to be hunting out in the woods, he's probably not going to be talking too loud but if he does something exciting and starts speaking normally you had better be ready to adjust the levels.

Over modulation is usually an issue with the transmitter, and the transmitter adjustment compensates for hot mics and loud venues. Adjust it using headphones connected to the receiver to ensure that you do not hear any distortion with the loudest sounds you want to capture distortion free.

Once you have set the transmitter level to be distortion free, set the receiver output level and camcorder input sensitivity to provide the desired record level. You will have to consult the wireless receiver manual as to its settings capability. In general, you want to receiver output level to reasonably match the camcorder input sensitivity. Most receiver "MIC" output levels are a good match to the XL1's MIC or MIC ATT sensitivity setting. MIC ATT is a preferred setting if you get enough output from the receiver to use it.

You have to run your own tests to decide which works best for you in your planned shooting situation.

Thanks guys, I guess my questions was missed... Is it ok for the mic transmitter levels and the receiver levels to be with range, but have the on camera monitor show that the incomming audio is sometimes spiking above the 12db mark on the camera. I run headphones and do not hear any distortion and I will run a test record and make sure it is not distorting but I do not like the fact like you stated James that if we are recording in the woods and he raises his voice that we don't have a spike. Also should I run the volume controls on the camera under the white flap on Auto or manual and adjust the recording levels there my self or let the camera do it? Thanks again for all the responses!!!

Yes. But generally speaking you do not want it spiking to 0 (zero) very often except perhaps for explosive or percussive sounds, like a gun shot or door slam, or maybe applause when sitting in the middle of an audience.

Ok, everything seems to sound great on film thanks for the help it is greatly appreciated. Now, to replace the stock mic on my camera and to be able to use 16bit will this be a good replacement shotgun mic, http://www.bhphotovideo.com/c/produc...otgun_Mic.html
Let me know your opinions!

Mics are very much a personal preference thing. It is all about sound. Like which camcorder do you like, or which film, or which brand of coffee or beer.

In my opinion, as shotgun mics go, there are much better models available for not a lot more money.

Potential issues with the Azden for serious use include: not a great signal to noise ratio, relatively high output impedance, and max sound pressure level is rather low.

If you check posts here in several different forums, a number of people have commented on their experience with the Azden shotguns. That may be of interest to you.

For just a bit more money, check out the AT837 and Rode NTG-2, which have some what of a following.