2016-07-16 (Sa) Binaural Recording Microphone

Tolerances on the print were not tight enough simply slide a captive bolt into place so the holes were all drilled with a 3/16" (5mm) drill bit then tapped with a 1/4-20 tap. The 1/4-20 tap doesn't need a metric conversion since it is the standard camera adapter.

 Drill index and tap going through the printed microphone holder

A 1/4-20 nut but forced into place using a long bolt as a handle. The loose printing tolerances made for a tight fit which is a good feature in this case. Instead of having to glue the nut in place friction will keep it steady. The hole below it was also tapped to 1/4-20 but it could have been drilled out so a tripod bolt could reach the nut.

1/4-20 bolt used as a handle for the nut

 Plastic adhesive was applied to the end face and the arc of the microphone holder. These surfaces will be touching the ear-shaped microphones. No modifications to these surfaces was necessary but it might have been wise to sand the outermost edge so it would have a flat surface.

Glue applied to arc and face

Ear-shaped microphones and the holder were held in place by hand until the bond was set. The glue was allowed to cure for ten minutes.

Microphone holder and left ear from the inside

Microphone holder and left ear from the outside

Both ears were given time to cure. A captive nut was put in place at the hole closest to the center of the microphone holder. Four holes were modeled into the holder each of them a different distance from the center. The purpose of the holes was to provide different options for adding a tripod mountable device like a camera or camera adapter for a phone.

Competed binaural microphone

A tablet computer and tablet tripod adapter were added to the microphone holder. A mobile phone can also be attached the same way but the phone was prone to putting interfering EM waves from the NFC and wifi antennas. These had to be turned off for recording so airplane mode was the safest bet to ensure no radio waves were being broadcasted.

Microphone holder with tablet installed on a tripod

One new binaural audio file was uploaded called "Microphone holder test and EM interference" and can be found below with the rest of the recordings. The recording was a street corner while standing under an awning during a light rain shower. During the three and a half minutes the rain slowed and stopped until there was only dripping. Cars pass by. It was supposed to be a pleasant soundscape but the problem of the EM interference is apparent. Shielding may be necessary.

Walking through and outdoor restaurant (1:43)
Walking around a lake (35:13)
Dropping things (0:37)
Knock on wood (0:02)
Microphone holder test and EM interference (3:29)

Microphone holder
Addamay's ear model on thingiverse

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1.

Completed projects from year 2.

Completed projects from year 3.

Disclaimer for http://24hourengineer.blogspot.com/

This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information in this blog, or linked by this blog, are not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.

2016-07-13 (Tu)