Audio Quality

Don Palomaki · September 3rd, 2007, 03:02 PM

Michael: What was the audio configuration when you shot? While not up to professional DAT audio standards (but then what camcorder is?), the sound from the A1 is pretty clean when appropriately configured. Was the A1 receiving the exact same sound source as the DAT and how was it connected to the camcorder?

Using +12 dB XLR audio gain up will make the noise floor pretty high and should be avoided.

Using LINE or MIC ATT setting will improve the noise floor, if your source has high enough output.

Using audio automatic gain can cause the noise to become more apparent during periods of softer audio input, and should be avoided if audio quality is critical.

The A1 has sufficient audio recording setup options that allow one to get good audio, or poor audio, just as one can get good video or poor video depending on how one uses the presets and exposure controls.

See http://www.dvinfo.net/conf/showthrea...ht=noise+floor for more data on the A1 audio capability.

Michael Blieden · September 6th, 2007, 09:35 PM

Quote:

Originally Posted by Jack Walker

Are you using a mixer and going into the camera at line level, or are you plugging the microphone directly into the camera?

Hey Jack,

I just checked with my sound mixer who worked on a scripted project that I shot, and he was definitely going into the camera at line level. This is discouraging news for me because people in this thread having been saying that at line level the audio is super quiet, but compared to the pro audio recording of the same audio signal, the canon is significantly louder, and compressed sounding. Now, to be fair, I'm comparing the canon audio with a professional hard drive recorder, which is a pro audio device recording uncompressed. But even if you give the canon a handicap for being a non audio dedicated device, it still has come out way too far behind for my taste.

The only wild card here is perhaps the audio cables themselves that went from the mixer to my camera. It is possible that they had something to do with degrading the signal, so I'm going to have to test it further.

As for the ATT switch for recording a mic level signal directly from the shotgun I will be testing that tomorrow.

Kelly Olsen · September 7th, 2007, 04:34 AM

This is all very interesting. I went to a three hour a1 seminar at Birns and Sawyer here in LA and the guy giving the seminar said to NEVER use line in off a pre-amp because for some unknown reason the camera will not give you decent results.

Said that he always uses mike in only. Don't have experience in this myself because I have been reluctant to move from my DVX after this and other statements about audio being below par. This was was not what I wanted to hear since I was planning on buying it at the end of the seminar, but that cooled my jets.

Don Palomaki · September 7th, 2007, 06:09 AM

Can you post a short sample of the poor sound?

Larry Secrest · September 13th, 2007, 07:31 AM

I'm thinking about getting the A1 to produce a film, but I just can't have bad sound. What I'm reading about the sound on the Sony V1 and the Canon A1 makes me want to shoot my project with the DVX100B.

Bill Pryor · September 13th, 2007, 08:57 AM

The camera I use at work is a DSR500, a 2/3" chip DVCAM, and for most interviews and dialog I use mic in. When there's more than one mic we use a mixer and line in. The audio quality of that camera is fine for everything I've done with it, including some stuff that was transferred to 35mm film.

When I got the XH A1 for personal use, one of the things I noticed about it is that its audio is significantly cleaner than the DSR500. So I don't have a problem at all with mic in on it. Sound studios, of course, have different standards. For dialog with actors, interviews, etc., the sound quality is perfectly good. If you are going to record a symphony orchestra, you might want to do double system and use a recorder.

And speaking of recorders, I've intercut sound from the DSR500 with double system sound from our Tascam DAT deck, and nobody can tell the difference. I also have a little Microtrack flash recorder with 1/4" inputs, and I've intercut its sound with the XH A1's and again nobody can hear any difference.

If you stick a mic on the camera and run it on auto gain, you are not going to get good sound. If you use a soundman with a decent shotgun mic on a boom, properly positioned, and/or good quality wireless mics also properly positioned, you will get good sound.

Larry Secrest · September 13th, 2007, 10:37 AM

I agree that to record a symphony you need highly specialized uncompressed recording devices. This is probably not of any interest to anybody interested in cams. Now you are saying that the A1 has cleaner audio that the uncompressed PCM audio than the DSR500?
Even though the A1 might be fine to take actors lines with a shotgun mic properly placed, aren't you pushing a little here? MPEG1 audio as clean as PCM audio?

Bill Pryor · September 13th, 2007, 11:36 AM

Yes, it sounds cleaner to me when comparing mic in to mic in. The DSR500 with line in was much cleaner than mic in. I haven't used the mixer yet with the Canon, other than a quick test to make sure line inputs worked, so I can't say about that.

Larry Secrest · September 13th, 2007, 09:35 PM

"Yes, it sounds cleaner to me when comparing mic in to mic in."

That is truly amazing to me.

Peter Moretti · September 14th, 2007, 03:59 AM

One thing to consider is that HDV compresses audio. So regardless of how clean the A1's sound is, you still wind up with compressed MP-2 audio.

To stay within DV's data rate, the HDV codec (among other things) compresses sound to give video more bandwidth.

This is considered okay if you aren't doing a lot post production work, but if you are going to do significant sound finishing, compressed audio is not what you want to be starting out with, FWIU.

Peter Moretti · September 14th, 2007, 04:07 AM

Quote:

Originally Posted by Kelly Olsen

This is all very interesting. I went to a three hour a1 seminar at Birns and Sawyer here in LA and the guy giving the seminar said to NEVER use line in off a pre-amp because for some unknown reason the camera will not give you decent results.

Said that he always uses mike in only. Don't have experience in this myself because I have been reluctant to move from my DVX after this and other statements about audio being below par. This was was not what I wanted to hear since I was planning on buying it at the end of the seminar, but that cooled my jets.

Kelly, one reason why the A1 shooting in HDV does not have as good sound as a DVX because a DVX is standard def and therefore records 16-bit uncompressed sound. Now before adding effects, the difference between uncompressed and MP-2 is considered pretty minor. But when effects are added to the audio, the difference can become rather significant, FWIBT.

If you want uncompressed audio recorded to the camera, you'd need to use a cam like the HVX, which records four uncompressed 16-bit tracks.

Shiv Kumar · September 14th, 2007, 10:22 PM

Michael,

All the videos I've done so far are interviews, using an Audio Technica Lav mic (but the lav is fixed to a boom in front (off camera) of the talent).

Yes, there is some hiss in the quiet passages due to the AC vent. However, in post (using Adobe's Soundbooth) it's very simple to take out monotomous sounds from the whole audio track. Even other unwanted sounds like doors slamming or cell phones ringing etc.

Take a look at these two videos. (if the video stops/starts, just let it buffer 100% before playing). The second video can be seen by clicking on the "Philosophy" button.

http://thehomefront.dynamicarchitect...ing/BuildOrbit

I've not altered/modified the sound in any way in these videos. In fact in the first one, the last two interview passages have the lav mic positioned in the front of the talent rather than cliped to her shirt. One can noticed a marked imporvement in clarity of voice in those last to passages as compared to the earlier.

Shiv Kumar · September 14th, 2007, 10:28 PM

To to add to my ealier note...

I used the XLR CH1 input (as Mono) and the mic was on a 25 foot XLR cable plus 6 feet cable of it's own.

Mikko Lopponen · September 15th, 2007, 11:38 AM

Quote:

Originally Posted by Larry Secrest

MPEG1 audio as clean as PCM audio?

There is no discernable quality difference between mp2 at 384kbps vs pcm. A different preamp will sound way different compared to another preamp than mp2 vs pcm will.

Peter Moretti · September 19th, 2007, 01:04 AM

Mikko,

From what I uderstand:

That is only the case if heavy effects or post work is not done on the sound.

One way MP-2 compresses is by removing sounds that are made inaudible by other sounds. E.g. you don't need a whisper immediately following a huge explosion, b/c the human ear can't adjust quickly enough to hear it. But remove the explosion in post, and you may be asking yourself "Where did the whisper go?"

Compression is fine for releasing the finished product, but if more work is going to be done on the sound, it can cause some problems. How serious an issue this is, I'm not sure. It has a lot to do with how much post work will be done and where the material will ultimately be played.

Again, this is what I've been told; I don't have experience taking a project to professional post house where these issues seem to become most important.

September 3rd, 2007, 03:02 PM	#16
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,487	Michael: What was the audio configuration when you shot? While not up to professional DAT audio standards (but then what camcorder is?), the sound from the A1 is pretty clean when appropriately configured. Was the A1 receiving the exact same sound source as the DAT and how was it connected to the camcorder? Using +12 dB XLR audio gain up will make the noise floor pretty high and should be avoided. Using LINE or MIC ATT setting will improve the noise floor, if your source has high enough output. Using audio automatic gain can cause the noise to become more apparent during periods of softer audio input, and should be avoided if audio quality is critical. The A1 has sufficient audio recording setup options that allow one to get good audio, or poor audio, just as one can get good video or poor video depending on how one uses the presets and exposure controls. See http://www.dvinfo.net/conf/showthrea...ht=noise+floor for more data on the A1 audio capability. __________________ dpalomaki@dspalomaki.com

September 7th, 2007, 06:09 AM	#19
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,487	Can you post a short sample of the poor sound? __________________ dpalomaki@dspalomaki.com

September 13th, 2007, 07:31 AM	#20
Larry Secrest Major Player Join Date: May 2007 Location: Bethesda, MD Posts: 404	This is not the only place I'm thinking about getting the A1 to produce a film, but I just can't have bad sound. What I'm reading about the sound on the Sony V1 and the Canon A1 makes me want to shoot my project with the DVX100B.

September 13th, 2007, 09:35 PM	#24
Larry Secrest Major Player Join Date: May 2007 Location: Bethesda, MD Posts: 404	Oh! "Yes, it sounds cleaner to me when comparing mic in to mic in." That is truly amazing to me.

September 7th, 2007, 04:34 AM	#18
Kelly Olsen Regular Crew Join Date: Jun 2007 Location: Santa Monica Posts: 26	This is all very interesting. I went to a three hour a1 seminar at Birns and Sawyer here in LA and the guy giving the seminar said to NEVER use line in off a pre-amp because for some unknown reason the camera will not give you decent results. Said that he always uses mike in only. Don't have experience in this myself because I have been reluctant to move from my DVX after this and other statements about audio being below par. This was was not what I wanted to hear since I was planning on buying it at the end of the seminar, but that cooled my jets.

September 13th, 2007, 08:57 AM	#21
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	The camera I use at work is a DSR500, a 2/3" chip DVCAM, and for most interviews and dialog I use mic in. When there's more than one mic we use a mixer and line in. The audio quality of that camera is fine for everything I've done with it, including some stuff that was transferred to 35mm film. When I got the XH A1 for personal use, one of the things I noticed about it is that its audio is significantly cleaner than the DSR500. So I don't have a problem at all with mic in on it. Sound studios, of course, have different standards. For dialog with actors, interviews, etc., the sound quality is perfectly good. If you are going to record a symphony orchestra, you might want to do double system and use a recorder. And speaking of recorders, I've intercut sound from the DSR500 with double system sound from our Tascam DAT deck, and nobody can tell the difference. I also have a little Microtrack flash recorder with 1/4" inputs, and I've intercut its sound with the XH A1's and again nobody can hear any difference. If you stick a mic on the camera and run it on auto gain, you are not going to get good sound. If you use a soundman with a decent shotgun mic on a boom, properly positioned, and/or good quality wireless mics also properly positioned, you will get good sound.

September 13th, 2007, 10:37 AM	#22
Larry Secrest Major Player Join Date: May 2007 Location: Bethesda, MD Posts: 404	I agree that to record a symphony you need highly specialized uncompressed recording devices. This is probably not of any interest to anybody interested in cams. Now you are saying that the A1 has cleaner audio that the uncompressed PCM audio than the DSR500? Even though the A1 might be fine to take actors lines with a shotgun mic properly placed, aren't you pushing a little here? MPEG1 audio as clean as PCM audio?

September 13th, 2007, 11:36 AM	#23
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	Yes, it sounds cleaner to me when comparing mic in to mic in. The DSR500 with line in was much cleaner than mic in. I haven't used the mixer yet with the Canon, other than a quick test to make sure line inputs worked, so I can't say about that.

September 14th, 2007, 03:59 AM	#25
Peter Moretti Trustee Join Date: Mar 2007 Location: Sherman Oaks, CA Posts: 1,259	One thing to consider is that HDV compresses audio. So regardless of how clean the A1's sound is, you still wind up with compressed MP-2 audio. To stay within DV's data rate, the HDV codec (among other things) compresses sound to give video more bandwidth. This is considered okay if you aren't doing a lot post production work, but if you are going to do significant sound finishing, compressed audio is not what you want to be starting out with, FWIU.

September 14th, 2007, 10:22 PM	#27
Shiv Kumar Major Player Join Date: Jul 2007 Location: Gainesville, VA, USA Posts: 327	Michael, All the videos I've done so far are interviews, using an Audio Technica Lav mic (but the lav is fixed to a boom in front (off camera) of the talent). Yes, there is some hiss in the quiet passages due to the AC vent. However, in post (using Adobe's Soundbooth) it's very simple to take out monotomous sounds from the whole audio track. Even other unwanted sounds like doors slamming or cell phones ringing etc. Take a look at these two videos. (if the video stops/starts, just let it buffer 100% before playing). The second video can be seen by clicking on the "Philosophy" button. http://thehomefront.dynamicarchitect...ing/BuildOrbit I've not altered/modified the sound in any way in these videos. In fact in the first one, the last two interview passages have the lav mic positioned in the front of the talent rather than cliped to her shirt. One can noticed a marked imporvement in clarity of voice in those last to passages as compared to the earlier.

September 14th, 2007, 10:28 PM	#28
Shiv Kumar Major Player Join Date: Jul 2007 Location: Gainesville, VA, USA Posts: 327	To to add to my ealier note... I used the XLR CH1 input (as Mono) and the mic was on a 25 foot XLR cable plus 6 feet cable of it's own.

September 19th, 2007, 01:04 AM	#30
Peter Moretti Trustee Join Date: Mar 2007 Location: Sherman Oaks, CA Posts: 1,259	Mikko, From what I uderstand: That is only the case if heavy effects or post work is not done on the sound. One way MP-2 compresses is by removing sounds that are made inaudible by other sounds. E.g. you don't need a whisper immediately following a huge explosion, b/c the human ear can't adjust quickly enough to hear it. But remove the explosion in post, and you may be asking yourself "Where did the whisper go?" Compression is fine for releasing the finished product, but if more work is going to be done on the sound, it can cause some problems. How serious an issue this is, I'm not sure. It has a lot to do with how much post work will be done and where the material will ultimately be played. Again, this is what I've been told; I don't have experience taking a project to professional post house where these issues seem to become most important.