C3 External Microphone Mod

[Conrod]

I've finally got round to producing a write-up of my external microphone mod - please see the attached PDF file.

I performed the initial testing using an album track, which enables direct comparisons to be more easily made. I need to edit these as they're huge WAV files at the moment, and then figure out how and where to upload them! For now, I've run them through Audacity to produce waveforms which hopefully show the huge improvement in audio dynamic range.

You can find larger photos in my Google+ Innovv C3 External Microphone Mod gallery here.

I should have my Cobra replica back on the road again within the next few days, so weather permitting I can hopefully make some comparitive "V8 music" recordings

I also plan to produce some comparison videos for two new non-fisheye lenses I've successfully installed in the C3 lens case, and will create a new thread for that when they're ready. Watch this space ......

 

[Nigel]

Do you not get any clipping with the sound of a V8? Looking at your traces, the C3 must have a good automatic microphone volume control?

 

[Conrod]

I haven't tried it yet Nigel. But I chose the audio track (Ipswich by Georgi Kay) because of it's high dynamic range and punchy bass, and it sounds superb, without any audio or visual (from Audacity) evidence of clipping). So yes, the AVC/ALC does seem to work very well in the C3!

Do you not get any clipping with the sound of a V8? Looking at your traces, the C3 must have a good automatic microphone volume control?

 

[Nigel]

I will be very interested to see the result when you have V8 power instead of some cardboard speaker cones!
I predict a load of red lines on the Audacity trace...

 

[Conrod]

Yes, I suspect my test system is no match for the 115dB from each sidepipe!

Eh??? Pardon???

 

[Conrod]

For completeness I've opened the original recording in Audacity and have appended the waveform to the Google+ gallery. You can see from that just how punchy this track is, and how well the microphone has captured this. I despair of the increasing trend for recordings to be compressed to death these days - Google "CD loudness wars" for further info. This track is a superb example of how music should sound, and it's one of my all-time favourites.

Incidentally, when I made the test recordings I accidentally stopped one of them before the end of the track, so I truncated them all to the same length and added a fade-out. That's why the one I've just posted looks different at the end!

 

[Conrod]

Good news and bad news!

The good news is that my Cobra is back on the road and after several hours work one the carburettor this afternoon (I've become quite an expert on Holley tuning now) it's now running almost perfectly - just a few more tweaks to go ....

The bad news is that, having focussed and reassembled my modified lens case (with a 70 degree lens), when I put the standard 90 degree lens case back together this morning one of the 14 internal wires seems to have broken again - so I only have one working C3 at the moment. Having resoldered one of these already I can't face doing it again - it's a real pain! So I'm ordering another lens module from Rock, which will obviously take a while to arrive here in the UK. But hopefully when it does summer will have truly started and I can then get cracking with the test/comparison videos in the Cobra!

Incidentally, I've suggested to Rock that he considers encasing the internal wires and terminal black inside the lens case in epoxy resin rather than the soft glue currently used. That should hold everything solidly together and prevent strain on the wires when the back of the lens case is unscrewed. The rubber grommet at the rear grips the cable too well, even if you try spraying silicone lubricant into it first, so the cable tends to twist with the rear of the lens case, stretching and breaking the wires internally. It's not an issue for normal users - only for us compulsive meddlers and tweakers!

 

[Biker]

I've finally got round to producing a write-up of my external microphone mod - please see the attached PDF file.

I performed the initial testing using an album track, which enables direct comparisons to be more easily made. I need to edit these as they're huge WAV files at the moment, and then figure out how and where to upload them! For now, I've run them through Audacity to produce waveforms which hopefully show the huge improvement in audio dynamic range.

You can find larger photos in my Google+ Innovv C3 External Microphone Mod gallery here.

I should have my Cobra replica back on the road again within the next few days, so weather permitting I can hopefully make some comparitive "V8 music" recordings

I also plan to produce some comparison videos for two new non-fisheye lenses I've successfully installed in the C3 lens case, and will create a new thread for that when they're ready. Watch this space ......

Thank you for charing, very interesting and you have made an excellent documentation!
A small tip, on all my cameras that I use for video with sound recordning I have taped a small pice of faux fur over the microphone hole. It takes away must of the wind noise.