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Getting decent video audio on your Seven


Croc

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Welcome Jeff! I am sure more than a few of us would be only to keen to help you get into a seven! Plenty of owners in TX who could take you out for a taster!

 

Does the replay mic that you are using allow you to set gain? I have not seen that feature in video mics before?

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The gain is not adjusted on the microphone. The gain setting, along with several other camera settings, resides in an editable text (txt) file that resides on the memory card. When the camera is powered up, the camera processer reads the settings on this text file. There are several settings that can be changed within the camera: exposure, sharpness, white balance, contrast, saturation, frame rate, mic gain, and so on.

 

The Replay microphone is a battery powered condenser microphone, just like the Audio-Technica ATR3350.

 

I know Paul Kwan in Houston, who has three Caterham Sevens. He's kindly let me drive two of them. It's partially his fault that sleep with pleasant dreams of driving a Seven. :)

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I made another attempt taking video on our trip from Los Angeles up to Canada to join the Grizzly Bear tour. This time I tried to do it the simple way(without the servo controlled swivel gadget I used to have) using a Drift Ghost HD attached to the windscreen frame and a remote mic behind the (full) windscreen. The matchbox size remote control is strapped to a steering wheel spoke. The camera can run in standby mode for 4-5 hours.

 

Video appears to be pretty good and the audio is also not bad in principle. No wind noise at all. However, I noticed when cruising long distance at e.g. constant 3000 rpm in fifth gear, the hissing noise of the tires on the road is usually louder than the exhaust or intake, except for the occasional burst when passing. But even the constant engine drone when cruising is not that appealing.

 

Not sure what to do with that. Maybe I need to find some appropriate background music, after all.

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Hello. My name is Jeff, and I've been a lurker of this forum for a while as some day I hope to be a 7 owner.

 

I've been reading this thread, as I too have been playing with POV cameras. I thoroughly enjoyed reading Croc evaluation of different cameras.

 

I drive a BMW Z4 M coupe in autocross and track events. I have the Replay XD 1080HD, and like xcarguy I love the video quality, but it was a challenge to get great audio quality. I too found the windbreakers not to solve the wind noise issue. I got the Replay external mic, and tried it in all different positions. The best location I found is in the engine bay, and the second best is with the microphone clipped on the rear license plate pointed towards the exhaust.

 

Here are some examples with the microphone mounted in the engine bay (gain setting at max 59 dB):

 

And on the rear plate:

 

JeffC,Thanks for the post. I'll be sure and check the dB level on my text file.

 

X

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  • 2 weeks later...

I am by no means an electronics expert, but my guess the whine is EMF from the alternator or ignition system (high energy coil, i.e. MSD).

 

There are filters you can buy and attach to the alternator, or MSD, to eliminate the noise. Search the net for more info.

 

You posted earlier that you use the external power option (12VDC accessory power jack). Have you tried unplugging that and running off of the internal battery alone? I wonder if EMF could be transmitted through the power cord.

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HAHAHA, I was sitting in the Dallas Ft Worth airport listening for that whine on my Iphone ear buds. I could make out the whine at the end just barely, but then it got a whole lot louder. Way louder! In fact it got so loud that the whine kept going after the video ended, which I thought was another plus for the I-Phone. Nah, it was just a door alarm going off. For a minute there, I thought you had a really bad alernator.

 

Tom

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I am by no means an electronics expert, but my guess the whine is EMF from the alternator or ignition system (high energy coil, i.e. MSD).

 

There are filters you can buy and attach to the alternator, or MSD, to eliminate the noise. Search the net for more info.

 

You posted earlier that you use the external power option (12VDC accessory power jack). Have you tried unplugging that and running off of the internal battery alone? I wonder if EMF could be transmitted through the power cord.

 

JeffC,

 

Thanks for the input. I have not tried using the internal (battery) camera power with an external mic. Once I get strapped in the car, It's a) hard to get to the buttons on top of the Reply with camera sitting above and behind me and b) it's easier to plug it in an external power supply and allow the camera to turn on and record automatically.

 

No MSD on my car, but the mic was positioned next to ECU wiring and almost directly in front of the ECU. I'm going to try moving the mic first and then go from there if I still have noise issues.

 

X

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I looked/listened at the latest results with the Drift Ghost HD again today on the big computer and better speakers. Actually not so bad, see short video/audio sample below. This is with the $30 Radioshack lavalier omnidirectional mic tucked with weatherstrip tape into the nook between windscreen frame and scuttle. The rubber weatherstrip insulates against direct body contact noise. This mic does not need a battery, apparently it gets its bias voltage from the camera. The camera mic sensitivity is set to minimum.

https://www.dropbox.com/s/s5igxuhpqs8dxeb/SoundTest1.avi

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I looked/listened at the latest results with the Drift Ghost HD again today on the big computer and better speakers. Actually not so bad, see short video/audio sample below. This is with the $30 Radioshack lavalier omnidirectional mic tucked with weatherstrip tape into the nook between windscreen frame and scuttle. The rubber weatherstrip insulates against direct body contact noise. This mic does not need a battery, apparently it gets its bias voltage from the camera. The camera mic sensitivity is set to minimum.

https://www.dropbox.com/s/s5igxuhpqs8dxeb/SoundTest1.avi

 

slomove,

 

In the video, before you make the turn, does the road straight ahead take you out to Kicking Horse :deadhorse: reservoir?

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slomove,

 

In the video, before you make the turn, does the road straight ahead take you out to Kicking Horse :deadhorse: reservoir?

 

I would not have known but looked it up on the Montana map and you are right. It is not exactly in Arkansas but you seem to know your way around there (or you cheated with help of Google maps and the street signs :) )

 

I picked the snippet because it was one of the spots to rev the engine at least somewhat.

Edited by slomove
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I would not have known but looked it up on the Montana map and you are right. It is not exactly in Arkansas but you seem to know your way around there (or you cheated with help of Google maps and the street signs :) )

 

I picked the snippet because it was one of the spots to rev the engine at least somewhat.

 

I either cheated . . . or I was in Kalispell a couple of weeks ago . . . or both :smash:. Okay, I was in Kalispell and Cranbrook on a company trip in late July; even had a sandwich and wings at Nickel Charlie's. I would never have looked up where you were had I not seen Kalispell on the road sign. :) Since I had also been in Cranbrook, I wanted to know if you were in Canada or Montana. Curiosity got the best of me. :seeya:

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Well, there is simply something about the Audio-Technica ATR-3550 Lavalier mic that my car does not like. After trying several different mic locations, the whine/squeal would not go away; at best, it became sporadic—mysteriously disappearing and then suddenly reappearing. I finally reverted back to using the Replay-supplied external lavalier mic, and presto, my whine/squeal problem vanished.

 

The following video clip was shot using the Replay camera with the Replay Hard Wire Car Adaptor (external power supply) and the Replay external mic (covered with an aftermarket foam windbreaker). The mic dB on the editable text was set to factory settings—33 dB (I’ve since edited the camera dB to 59—max setting—but have not had a chance to try it out). In the video, the mic is positioned underneath the rear cover, between the fuel tank and the bulkhead. Since I have a diffuser on the car, this area is fairly well isolated from wind.

 

The best sound spots in the video are at 2:10, 2:50, 3:30 and 4:36. At 3:30, I do a series of quick shifts in the 5-to-6k rpm range.

 

 

Edited by xcarguy
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Gale,

 

I believe you are right. In Sept, I'll be back at MSR Cresson; I think the same weekend you guys will be wrapping up the Ambush. Hopefully, I'll get some decent on-track vids with motor.

Edited by xcarguy
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  • 2 weeks later...
.....the mic is positioned underneath the rear cover, between the fuel tank and the bulkhead. Since I have a diffuser on the car, this area is fairly well isolated from wind.

 

 

I think you have nailed it - thats what it should sound like. A bit of clunky metal on the gear change - a bit like the Ferrari metal gear gate sound? I assume that is the linkages I am hearing? Also at the 3.30 mark you can hear just one spot where the mic got overwhelmed by the sound and distorted - that is pretty good.

 

Next test will be to see how well it works on a track as the wind noise will appear there if anywhere, along with the distortion from the greater sound loads.

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I think you have nailed it - thats what it should sound like. A bit of clunky metal on the gear change - a bit like the Ferrari metal gear gate sound? I assume that is the linkages I am hearing?

 

 

The clunky metal sound during the gear changes is the faceplating modifications on second, third and forth gears . . . kind of sounds like two hammers competing for the first blow with each change, especially when shifting at low rpm's. :smash::smash:

 

Cresson on the 14th will be the truth-teller for the mic and its location.

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