Xi External Mic levels at DVinfo.net

Jason Dirks · February 23rd, 2005, 07:20 PM

Hello Again,

Well I purchased the Azden SGM-2x to use as my external shotgun mic, and I have to say I'm very pleased with the overall quality of it. Used the roll-off and came through with nice clarity and sound quality. I'm also using the beachtek 4p audio adapter.

There is one thing that I'm a bit confused on, however. Let me preface by saying this was a test I did myself with no one to help monitor mic placement or levels. That being said, I had the mic at a relatively close distance (12"-15" from my mouth above my head), at a slight angle, but not one that affected the overall quality. I changed the audio control on the Xi to manual and I had to boost it up to just under 0 db's. That's just about maxed out. Again sound quality was good, but any time you open it up that much you get ambient noise behind it. And, to boot, once I imported it into FCE I still had to boost the audio level to +7 to get to a nice level that was pretty loud, but didn't clip in the loudest sections.

I guess my question is, does this sound like a normal operating procedure? Obviously, every mic is different, but I would think with a condenser mic like this that is indepently powered (via AAA battery in the barrel) I shouldn't have to jack up the levels as much as I did. Any suggestions overall as well when using an external shotgun mic?

Appreciate any advice. Thanks.

Jason

Ty Ford · February 26th, 2005, 06:57 AM

Your excercise (mic adjustment, placement and levels) was a good practical approach.

The fine points of the gear and exactly how you used it (and what it may be capable of) are the issue.

As I told my client yesterday after he copied some CD tracks to one CD to bring to me for an edit, "Good audio is not trivial."

I'm not sure what he did, but he did something wrong. The files were clipped. He had the original CDs as a safety. When we checked the originals, the audio was fine.

Regards,

Ty Ford

David Ennis · February 26th, 2005, 09:18 AM

I've read complaints about the SGM-2X sensitivity before. I'm quite sure that the problem is that it has an output impedance of 680 ohms. Azden touts this as a low impedance, but it's not really, when compared to popular AT and Sennheiser mics which run from 100 to 250 ohms. 680 ohms is a mismatch for the BeachTek DXA-4P's input impedance of 200 ohms. I'd expect that to result in a recording level 6 to 10 dB below AT or Sennheiser mics with similar open circuit sensitivity specs.

If I'm right, it should perform better as a camera mounted mic with an XLR to 1/8" mini adaptor plugged directly into the cam's mic jack, which is probably at least several thousand ohms.

Jason Dirks · February 26th, 2005, 09:42 AM

Thanks for the comments and the potential solutions. I'll try the mini-plug adapter (though, to be honest, because of the great potential of the beachtek adapter, I'm considering maybe trading out the Azden for a different mic). I'll definitely try going directly into the camera's audio in to see if that makes a difference.

Fred, I guess the other question I have is because I was just recording dialogue, it would probably be stupid of me to expect levels floating between -3db and 0. In fact, I read something the other day that says dialogue levels should hover somewhere between -12db and -6db. And I suppose that makes sense because if you overlay instrumental music, for an example, that audio will fill primarily your left and right field while the dialogue fills the center. Then you can adjust all of it until you get to an acceptable loudness level.

I'm just kind of thinking out loud, but let me know if I'm on the right track. I've been recording music for years, but have taken a recent foray into DV. One of the things that always bothered me coming out of my home studio with any work I had done is how you can never get to loudness levels that you find on commercial CD's without clipping. I'm sure most of that is due to my mastering inexperience, but I'd love to hear anyone else's thoughts. Thanks.

David Ennis · February 26th, 2005, 11:12 AM

Mics and recorders vary of course, but my sense is that at studio distances dialog levels with the average mic will provide -12 to -6 dB to the average recorder without having to adjust too far from mid gain. From the measurements I recently made and posted here, I know it would be true of one of my AT3031 mics and my GL2.

Regarding the volume of commercial CD's compared to what you and I record, I think the difference is sophisticated compression. If you reduce the dynamic range, you can boost the levels of the whole recording up. As a matter of fact I've started to experiment with software compression for my videos.

Jason Dirks · February 26th, 2005, 11:39 AM

To your point, it would be nice if I could get -12 to -6db without having to boost my levels. But I have to go to at least -6 to get to peaks of -12.

I agree w/ the thoughts on compression. That's not the first time I've heard that. I also know that radio stations run music through a series of compressors and then, to your point, boost the whole thing. That's why when you listen to songs on the radio, parts that may have intentionally been recorded softer for mood never seem to sound that way on the radio. Everything is about the same volume.

I'm using Peak as my external audio editor (both for my final cut projects and music projects) and I know it has some compression capabilities, but I haven't experimented with it that much.

Thanks for the help, Fred.

February 23rd, 2005, 07:20 PM	#1
Jason Dirks Regular Crew Join Date: Jan 2005 Location: Ohio Posts: 27	Xi External Mic levels Hello Again, Well I purchased the Azden SGM-2x to use as my external shotgun mic, and I have to say I'm very pleased with the overall quality of it. Used the roll-off and came through with nice clarity and sound quality. I'm also using the beachtek 4p audio adapter. There is one thing that I'm a bit confused on, however. Let me preface by saying this was a test I did myself with no one to help monitor mic placement or levels. That being said, I had the mic at a relatively close distance (12"-15" from my mouth above my head), at a slight angle, but not one that affected the overall quality. I changed the audio control on the Xi to manual and I had to boost it up to just under 0 db's. That's just about maxed out. Again sound quality was good, but any time you open it up that much you get ambient noise behind it. And, to boot, once I imported it into FCE I still had to boost the audio level to +7 to get to a nice level that was pretty loud, but didn't clip in the loudest sections. I guess my question is, does this sound like a normal operating procedure? Obviously, every mic is different, but I would think with a condenser mic like this that is indepently powered (via AAA battery in the barrel) I shouldn't have to jack up the levels as much as I did. Any suggestions overall as well when using an external shotgun mic? Appreciate any advice. Thanks. Jason

February 26th, 2005, 06:57 AM	#2
Ty Ford Inner Circle Join Date: Nov 2004 Location: Baltimore, MD USA Posts: 2,337	Your excercise (mic adjustment, placement and levels) was a good practical approach. The fine points of the gear and exactly how you used it (and what it may be capable of) are the issue. As I told my client yesterday after he copied some CD tracks to one CD to bring to me for an edit, "Good audio is not trivial." I'm not sure what he did, but he did something wrong. The files were clipped. He had the original CDs as a safety. When we checked the originals, the audio was fine. Regards, Ty Ford __________________ Ty Ford's Audio Bootcamp Field Guide Ty Ford's Audio Video Blog

February 26th, 2005, 09:18 AM	#3
David Ennis Fred Retread Join Date: Jul 2004 Location: Hartford, CT Posts: 1,227	I've read complaints about the SGM-2X sensitivity before. I'm quite sure that the problem is that it has an output impedance of 680 ohms. Azden touts this as a low impedance, but it's not really, when compared to popular AT and Sennheiser mics which run from 100 to 250 ohms. 680 ohms is a mismatch for the BeachTek DXA-4P's input impedance of 200 ohms. I'd expect that to result in a recording level 6 to 10 dB below AT or Sennheiser mics with similar open circuit sensitivity specs. If I'm right, it should perform better as a camera mounted mic with an XLR to 1/8" mini adaptor plugged directly into the cam's mic jack, which is probably at least several thousand ohms. __________________ "Nothing in the world can take the place of persistence..." - Calvin Coolidge "My brain is wired to want to know how other things are wired." - Me

February 26th, 2005, 11:12 AM	#5
David Ennis Fred Retread Join Date: Jul 2004 Location: Hartford, CT Posts: 1,227	Mics and recorders vary of course, but my sense is that at studio distances dialog levels with the average mic will provide -12 to -6 dB to the average recorder without having to adjust too far from mid gain. From the measurements I recently made and posted here, I know it would be true of one of my AT3031 mics and my GL2. Regarding the volume of commercial CD's compared to what you and I record, I think the difference is sophisticated compression. If you reduce the dynamic range, you can boost the levels of the whole recording up. As a matter of fact I've started to experiment with software compression for my videos. __________________ "Nothing in the world can take the place of persistence..." - Calvin Coolidge "My brain is wired to want to know how other things are wired." - Me

February 26th, 2005, 09:42 AM	#4
Jason Dirks Regular Crew Join Date: Jan 2005 Location: Ohio Posts: 27	Thanks for the comments and the potential solutions. I'll try the mini-plug adapter (though, to be honest, because of the great potential of the beachtek adapter, I'm considering maybe trading out the Azden for a different mic). I'll definitely try going directly into the camera's audio in to see if that makes a difference. Fred, I guess the other question I have is because I was just recording dialogue, it would probably be stupid of me to expect levels floating between -3db and 0. In fact, I read something the other day that says dialogue levels should hover somewhere between -12db and -6db. And I suppose that makes sense because if you overlay instrumental music, for an example, that audio will fill primarily your left and right field while the dialogue fills the center. Then you can adjust all of it until you get to an acceptable loudness level. I'm just kind of thinking out loud, but let me know if I'm on the right track. I've been recording music for years, but have taken a recent foray into DV. One of the things that always bothered me coming out of my home studio with any work I had done is how you can never get to loudness levels that you find on commercial CD's without clipping. I'm sure most of that is due to my mastering inexperience, but I'd love to hear anyone else's thoughts. Thanks.

February 26th, 2005, 11:39 AM	#6
Jason Dirks Regular Crew Join Date: Jan 2005 Location: Ohio Posts: 27	To your point, it would be nice if I could get -12 to -6db without having to boost my levels. But I have to go to at least -6 to get to peaks of -12. I agree w/ the thoughts on compression. That's not the first time I've heard that. I also know that radio stations run music through a series of compressors and then, to your point, boost the whole thing. That's why when you listen to songs on the radio, parts that may have intentionally been recorded softer for mood never seem to sound that way on the radio. Everything is about the same volume. I'm using Peak as my external audio editor (both for my final cut projects and music projects) and I know it has some compression capabilities, but I haven't experimented with it that much. Thanks for the help, Fred.