HPX170 audio question at DVinfo.net

Andy Tejral · April 27th, 2009, 02:11 PM

I'm gettin' ready to buy one these puppies but I got a question:

There is a great audio technique that I haven't been able to use. When you are expecting loud sounds but won't be able to adjust the level, set one channel to, say, zero and the other to -15. So, when the loud sound comes, you use the quieter one in post.

But, I shoot stereo so this doesn't work on a 2 channel system (dv/hdv).

Can I record from an external mic to channels 1/2 and the internal mic to channels 3/4 at a reduced level? From what I've read, it doesn't seem to be the case...

If'n ya care, the subject will be trains--the horns are extremely loud but the cars themselves are comparatively extremely quiet. So, if'n ya got any other workarounds, I'm happy to listen.

Dan Brockett · April 27th, 2009, 03:15 PM

You can offset Ch1 and 2 but you have NO control over 3 and 4 other than to disable these two channels or enable them.

Basically 3 and 4 are useless on the lower end P2 cams, not sure why they even have them there. On the higher end camera beginning with the HPX300, having more than two channels is actually useful for something.

Will you be shooting trains in temperatures of less than 32 degrees Fahrenheit? If so, make sure you check out the threads over on DVX User about people in colder states (I live in California, what's cold?) the some issues with the focus ring on the 170. If manually focusing in the cold is relevant to your needs, might be a deal breaker on the 170, you might have to get the 200a instead.

Dan

Andy Tejral · April 27th, 2009, 06:33 PM

Huh, interesting.

I added a post there asking if people were making valid comparisons--200a vs 170 not 200 vs 170. Barry Green seemed to back up Panasonic saying the problem did manifest itself on the 200a.

I'm not sure how big a deal it really is--I generally stay near infinite focus and don't mess with it. If if did work on the Iditarod albiet not very well, that's good enough for me.

Back to the audio issue: no control over 3/4 means AGC? Or will it distort if it gets loud? Not that that will help me much--most AGC/limiting doesn't have a quick enough attack for train horns.

Andy Tejral · April 28th, 2009, 06:41 AM

Yes, it seems to be confirmed over on DVX user: the issue is with old/new cameras--the 200a and the 150 has the sticky focus issue and the older 200(no a) does not.

Dan Brockett · April 28th, 2009, 08:12 AM

3 and 4 are camera mic only and average levels (not AGC technically) only. It probably will not give you the quality you are seeking. But why would just using quality mics on inputs 1 and 2 not suffice?

Dan

Andy Tejral · April 28th, 2009, 08:54 AM

Quote:

Originally Posted by Dan Brockett

But why would just using quality mics on inputs 1 and 2 not suffice?

Basically due to the unpredictable nature of train horns and the small amount of time to adjust levels between horn (extremely loud), engine (very loud), and cars (relatively very quiet). Ideally, I'd like to have one 'normal' setup and one for 'very loud'. If you could control the level on 3/4, it would be perfect--sound quality on the horns isn't very important as long as it isn't distorted.

Yes, I could use a external audio recorder but for run and gun--following trains along the line, the smaller amount of equipment the better.

Indeed, the unpredictable nature of trains in general is why I want this camera--even the 3 second pre-record will be a big help.

Andy Tejral · April 28th, 2009, 12:00 PM

I've just been looking into the Zoom H2. That seems like it has a lot of potential--surround sound would be a big plus for the recordings. Then I could set the camera audio to record very low and drop that in when the H2 distorts (not if, when).

If only there were a way to sync the record buttons together...

Barry Green · April 28th, 2009, 12:41 PM

Put your external mics on 3 & 4, and run them through a MixPre or other external mixer. That way you can control the levels of 3 & 4. Put the internal built-in mic on 1 & 2, and use the camera's level controls for those.

Andy Tejral · April 28th, 2009, 01:47 PM

Ah, how I would love to own something like the MixPre. Sound Devices looks like they make some pretty neat stuff. Plus their limiter sounds like it might actually do the job for what I need.

Alas, that is way out of my price range. For people of means, that makes a great solution.

No, I think the Zoom H2 should do pretty well for me. I've been to many locations where the echoing sound is fantastic. While you'd still hear it in stereo, to have it in surround makes it worth the while.

Heck, the cheapest mixer, with metering, B&H has is more expensive than the Zoom H2.

Dick Campbell · April 29th, 2009, 03:05 PM

You're not really recording stereo separation when you do this. Why not just set Ch 1 for the quiet cars, and Ch2 for the loud horns, and remix in post?

Andy Tejral · April 29th, 2009, 08:52 PM

Quote:

Originally Posted by Dick Campbell

You're not really recording stereo separation when you do this. Why not just set Ch 1 for the quiet cars, and Ch2 for the loud horns, and remix in post?

What do you mean? When I do what?

Admittedly, I'm using a fairly low end stereo mic (ECM-MS957) but to my ears, it does a really nice job of capturing the ambience. I've heard mono and stereo train videos and I definately prefer the stereo. I think the surround of the Zoom H2 has definate possibilities.

April 27th, 2009, 02:11 PM	#1
Andy Tejral Major Player Join Date: Jan 2007 Location: New York City Posts: 523	HPX170 audio question I'm gettin' ready to buy one these puppies but I got a question: There is a great audio technique that I haven't been able to use. When you are expecting loud sounds but won't be able to adjust the level, set one channel to, say, zero and the other to -15. So, when the loud sound comes, you use the quieter one in post. But, I shoot stereo so this doesn't work on a 2 channel system (dv/hdv). Can I record from an external mic to channels 1/2 and the internal mic to channels 3/4 at a reduced level? From what I've read, it doesn't seem to be the case... If'n ya care, the subject will be trains--the horns are extremely loud but the cars themselves are comparatively extremely quiet. So, if'n ya got any other workarounds, I'm happy to listen. __________________ Andy Tejral Railroad Videographer

April 27th, 2009, 06:33 PM	#3
Andy Tejral Major Player Join Date: Jan 2007 Location: New York City Posts: 523	Huh, interesting. I added a post there asking if people were making valid comparisons--200a vs 170 not 200 vs 170. Barry Green seemed to back up Panasonic saying the problem did manifest itself on the 200a. I'm not sure how big a deal it really is--I generally stay near infinite focus and don't mess with it. If if did work on the Iditarod albiet not very well, that's good enough for me. Back to the audio issue: no control over 3/4 means AGC? Or will it distort if it gets loud? Not that that will help me much--most AGC/limiting doesn't have a quick enough attack for train horns. __________________ Andy Tejral Railroad Videographer

April 28th, 2009, 06:41 AM	#4
Andy Tejral Major Player Join Date: Jan 2007 Location: New York City Posts: 523	Yes, it seems to be confirmed over on DVX user: the issue is with old/new cameras--the 200a and the 150 has the sticky focus issue and the older 200(no a) does not. __________________ Andy Tejral Railroad Videographer

April 28th, 2009, 12:00 PM	#7
Andy Tejral Major Player Join Date: Jan 2007 Location: New York City Posts: 523	I've just been looking into the Zoom H2. That seems like it has a lot of potential--surround sound would be a big plus for the recordings. Then I could set the camera audio to record very low and drop that in when the H2 distorts (not if, when). If only there were a way to sync the record buttons together... __________________ Andy Tejral Railroad Videographer

April 28th, 2009, 01:47 PM	#9
Andy Tejral Major Player Join Date: Jan 2007 Location: New York City Posts: 523	Ah, how I would love to own something like the MixPre. Sound Devices looks like they make some pretty neat stuff. Plus their limiter sounds like it might actually do the job for what I need. Alas, that is way out of my price range. For people of means, that makes a great solution. No, I think the Zoom H2 should do pretty well for me. I've been to many locations where the echoing sound is fantastic. While you'd still hear it in stereo, to have it in surround makes it worth the while. Heck, the cheapest mixer, with metering, B&H has is more expensive than the Zoom H2. __________________ Andy Tejral Railroad Videographer

April 27th, 2009, 03:15 PM	#2
Dan Brockett Inner Circle Join Date: Feb 2006 Location: Los Angeles, California Posts: 2,109	You can offset Ch1 and 2 but you have NO control over 3 and 4 other than to disable these two channels or enable them. Basically 3 and 4 are useless on the lower end P2 cams, not sure why they even have them there. On the higher end camera beginning with the HPX300, having more than two channels is actually useful for something. Will you be shooting trains in temperatures of less than 32 degrees Fahrenheit? If so, make sure you check out the threads over on DVX User about people in colder states (I live in California, what's cold?) the some issues with the focus ring on the 170. If manually focusing in the cold is relevant to your needs, might be a deal breaker on the 170, you might have to get the 200a instead. Dan

April 28th, 2009, 08:12 AM	#5
Dan Brockett Inner Circle Join Date: Feb 2006 Location: Los Angeles, California Posts: 2,109	3 and 4 are camera mic only and average levels (not AGC technically) only. It probably will not give you the quality you are seeking. But why would just using quality mics on inputs 1 and 2 not suffice? Dan

April 28th, 2009, 12:41 PM	#8
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	Put your external mics on 3 & 4, and run them through a MixPre or other external mixer. That way you can control the levels of 3 & 4. Put the internal built-in mic on 1 & 2, and use the camera's level controls for those.

April 29th, 2009, 03:05 PM	#10
Dick Campbell Regular Crew Join Date: Jul 2005 Posts: 117	You're not really recording stereo separation when you do this. Why not just set Ch 1 for the quiet cars, and Ch2 for the loud horns, and remix in post?