XH a1 sound question at DVinfo.net

Walter R. Scott · February 19th, 2008, 09:56 PM

Has any one done this and what were the results ? I was think of putting a wireless into channel 1 and a wired mic into channel 2. At times I am sure they will be picking up the same audio. Will I notice a delay on the wired mic when the person with the wireless is far from the camera? I want to use the wired mic for ambiant sound.

Todd Smaretsky · February 19th, 2008, 10:49 PM

I am new to this, but I experimented with the same issue and I heard no delay.

Don Palomaki · February 20th, 2008, 08:06 AM

Sound travels at about 1100 ft/sec (depending on air temperature, pressure, etc.) . Radio waves and light are nearly instantaneous. So you can expect the audio from the wired mic to lag the wireless mic (and image action if the image is on the wireless mic location) by about one frame (assuming 60i) for every ~37 feet the wired mic is more distant from the sound source than the wireless mic.

However, whether or not it will be an issue depends on the sound source. distances involved, and how you are using/mixing it in the final product. If uncompensated it can add a sort of echo or reverberation effect. BTW: Most single point microphones will not do a very good job of picking up the sound of a person speaking at a distance, whey work best within a few feet of the person where the delay would not be an issue.

A viewer will notice the apparent shift in sound sync if the distances/lag is large enough (more than a frame or two) but also will usually adapt to it quickly, especially if the program is more interesting than the production artifacts.

Walter R. Scott · February 20th, 2008, 10:42 AM

Don you are a busy guy! Thank you for the numbers. Having the numbers makes the situation clearer. Is there a better way to do this?

Don Palomaki · February 20th, 2008, 11:28 AM

What you propose works reasonably well, especially for events like weddings, where options are somewhat limited.

Typically the camcorder mic gets ambient sound, the wireless gets the talent. And you mix the sound in post to get the combination you want, typically more wireless than ambient. Typically you would not want to switch between the two different mics for the same sound source and scene if you can avoid it because the differences in sound quality/tone may be distracting. If the delay is distracting, using a NLE you can decouple the audio and video tracks, and shift the audio on the time line for improved lip sync.

Recommendation beyond the above general observations would require more detailed information on what you plan to do, the venue, the final product, the end user/consumer, and your artistic intent/agenda.

February 19th, 2008, 09:56 PM	#1
Walter R. Scott New Boot Join Date: Feb 2008 Location: Sheridan Oregon Posts: 9	XH a1 sound question Has any one done this and what were the results ? I was think of putting a wireless into channel 1 and a wired mic into channel 2. At times I am sure they will be picking up the same audio. Will I notice a delay on the wired mic when the person with the wireless is far from the camera? I want to use the wired mic for ambiant sound.

February 20th, 2008, 08:06 AM	#3
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,487	Sound travels at about 1100 ft/sec (depending on air temperature, pressure, etc.) . Radio waves and light are nearly instantaneous. So you can expect the audio from the wired mic to lag the wireless mic (and image action if the image is on the wireless mic location) by about one frame (assuming 60i) for every ~37 feet the wired mic is more distant from the sound source than the wireless mic. However, whether or not it will be an issue depends on the sound source. distances involved, and how you are using/mixing it in the final product. If uncompensated it can add a sort of echo or reverberation effect. BTW: Most single point microphones will not do a very good job of picking up the sound of a person speaking at a distance, whey work best within a few feet of the person where the delay would not be an issue. A viewer will notice the apparent shift in sound sync if the distances/lag is large enough (more than a frame or two) but also will usually adapt to it quickly, especially if the program is more interesting than the production artifacts. __________________ dpalomaki@dspalomaki.com

February 20th, 2008, 11:28 AM	#5
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,487	What you propose works reasonably well, especially for events like weddings, where options are somewhat limited. Typically the camcorder mic gets ambient sound, the wireless gets the talent. And you mix the sound in post to get the combination you want, typically more wireless than ambient. Typically you would not want to switch between the two different mics for the same sound source and scene if you can avoid it because the differences in sound quality/tone may be distracting. If the delay is distracting, using a NLE you can decouple the audio and video tracks, and shift the audio on the time line for improved lip sync. Recommendation beyond the above general observations would require more detailed information on what you plan to do, the venue, the final product, the end user/consumer, and your artistic intent/agenda. __________________ dpalomaki@dspalomaki.com

February 19th, 2008, 10:49 PM	#2
Todd Smaretsky Regular Crew Join Date: Sep 2007 Location: Los Angeles, CA Posts: 36	I am new to this, but I experimented with the same issue and I heard no delay.

February 20th, 2008, 10:42 AM	#4
Walter R. Scott New Boot Join Date: Feb 2008 Location: Sheridan Oregon Posts: 9	Don you are a busy guy! Thank you for the numbers. Having the numbers makes the situation clearer. Is there a better way to do this?