Archive for the ‘Hardware’ Category

Hat Mics on the road

September 4, 2010 Leave a comment

I recently went on a San Juan River fly fishing trip with my dad and brothers, my brothers traveled separately, so it was just my dad and I for the 3 hour drive from Rio Rancho to Navajo Dam, NM.

My dad was visiting from Florida for more than a week, so it was a great opportunity to interview him and ask random questions to help me and my kids understand his family history as he knew it.  All total I have about 6 hours of recording just talking with dad, I learned many new things that I did not know before.

Since both my dad and I wear baseball caps, it was a excellent chance to use the Hat Mic technique and my Olympus LS-10 as detailed in a previous post here.

There was a fair amount of road noise in the recording from the Toyota Tundra truck.  I also noticed that the road noise level changed as the truck went over bridges and rougher patches of road.

Here is a sample of the recording so you can hear what this particular setup sounds like.


– Dom

Direct link to the MP3 audio:

Microphone placement for interviews … the “Hat Mic”

August 12, 2010 Leave a comment

Here is a very good microphone placement technique I learned years ago for recording audio interviews and corporate educational materials.  Some people have called this the “Hat Mic” or “Hat (Mic) Trick” technique.  I’m posting this so more people can learn this great miking technique.

It involves is clipping a lavalier/lapel microphone to the brim of a baseball cap as shown here:

Then putting on the hat mic and running the microphone cable behind a ear and to the recorder or computer mic port.

This miking technique has several advantages.  The most important ones are a constant fixed distance between the speaker’s mouth and the microphone (really helps with setting gain levels) and the microphone is out of the breath path of the person speaking (removes breathing on the mic and plosives).

Here is a MP3 audio example of the the hat mic technique in action.

Here is a direct link to the MP3 example:

The WAV audio was recorded with a Olympus LS-10 and “Hat Mic”.  The MP3 audio was edited and produced using Audacity and the Levelator.

Here are the blog posts where I initially found and learned about the Hat Mic technique.

Hope this was useful. Enjoy!

– Dom

How to record and produce a MP3 file from a 2 person interview

August 10, 2010 Leave a comment

When I record audio interviews, I usually choose between 2 hardware setups depending on the situation.

The first setup is for ultra-light portable field recording without any power nearby or audio mixer to plug into.  This comprises primarily of a Olympus LS-10 digital audio recorder, 2 lavalier/lapel wired microphones with 1/8 mono connectors, and a Y connector which connects each mono connector to the right or left stereo input on the LS-10.  Click on the image to see a larger version.

The second setup is also for field recording that gives me more options to either plug into an existing audio mixer, or use higher quality phantom powered wired or wireless microphones.  It’s made up of a Marantz PMD661 digital audio recorder and paired with a couple Shure Beta58A microphones (as pictured) or a couple Shure PGX wireless lavalier/lapel microphones (these require AC power nearby).

One of the more important points about recording interviews is microphone placement.  I prefer to use the lavalier/lapel microphones when I can because it allows me to place the microphone at a consistent distance from the mouth of the person talking and there is little chance for handling noise.  With hand-held microphones, moving of the hand on the surface of the mic can cause audio noise to be picked up by the recorder.

One tip on using the devices, the Olympus LS-10 can be setup to use Auto-Gain or Fixed-Gain, the gain applies to BOTH left and right channels at the same time, there is no individual gain for each channel.  On the Marantz PMD661, each channel has it’s own gain and can be adjusted independently depending on the person’s speaking volume.

Once I am done with the recording, I take the WAV file from either recorder, run the file through the Levelator, and edit them using Audacity (remove parts I don’t want).  Once all the editing it done, the audio is then rendered (or produced) into MP3 format.

Below is a video I made of the production process using Audacity & the Levelator (the audio used was recorded using the Olympus LS-10 setup):


– Dom

Here is the video link for those who can’t see the embedded viewer:

Here is the MP3 file so you can hear it outside youtube:

Here is the direct link to the MP3 file:

The video was made and rendered in 720p using Tech Smith’s Camtasia Studio 7.

Modified iSkin revo case for iPhone 4

July 8, 2010 1 comment

Ok, I’m waiting for a email from on when their new iPhone 4 silicone cases will be available, no email yet, it’s been a week since adding my name, and 2 weeks since the phone has been out.  You can also see my iPhone 4 review here.

In the meantime, I took my iSkin revo case which I had for my original iPhone and modified it somewhat so I can use the 2 cameras on my new iPhone 4.  The older cases are still being sold on the iSkin website for $20.

Here is what the new modified case looks like, I removed material on the left side of the earpiece opening so the front camera is not covered & increased the camera hole size in the back to show the full lens and the led light.  The tools used, a paper hole puncher and small wire cutters.

These photos were taken using the iPhone 4 & uploaded to twitpic while waiting for a to-go order at the local Lotaburger (they have purple tables).

Additional photos below of the iPhone in the modified revo case below.

Now I can take pics and shoot video with the iPhone protected by a case.

– Dom

Dominic’s iPhone 4 Review

July 5, 2010 Leave a comment

I was teaching in San Ramon, CA when my new iPhone 4 arrived at the house last week.  My wife and I have had some of the original iPhones for several years and liked them (we also protected our phones using the iSkin revo).  We decided to continue with the new iPhones due to being grandfathered into the unlimited data plan, and I can use the phone when I travel internationally (because it uses a GSM radio versus CDMA).

I activated our phones after getting back on Friday (7/2) and started using our iPhone 4s.

I can say these phones are beautiful and no picture I can take will do any justice to the ones on the Apple website here.  My brother Pat, who is an expert working with stainless steel was impressed with the new industrial design.

I was disappointed to find the lack of cases available for the new iPhone 4, it’s one of the first things I put on any mobile device that I will own for any number of years.  I did hear about the “bumper” through Apple, but I don’t like the lack of protection at the front and back of the phone (2 pieces of glass to worry about now).  I’m going to wait for the new iSkin case for the iPhone 4.  I really like this case because of the removable plastic display cover to protect the multi-touch screen.  Since one is not available, I’m using the original iSkin revo case on our new iPhones, they work quite nice.  Here are some pics (original iPhone on left, iPhone 4 on right):

I’m not too concerned about the antenna issue that seems to be swirling around the new iPhone (maybe because I have a bit of background in the electrical engineering area 😉 ), but the exposed antenna on the edge of the device did surprise me (things like this are usually insulated), glad the iPhone will be in a case.  It’s funny, the “bars” on the phones are from the analog days of mobile phones, with the new digital phones, either there is a signal or not, pretty simple, more bars don’t mean better call quality.  Most of the newer phones have internal antennas and can experience the same effects when a hand or body gets in the middle of the phone and the tower it needs to talk to (also because of the cellular technology one can be switching between towers at any time).  This also reminded me that not too long ago we had antennas on the outside of our mobile phones, I still have one lying around:

Of course, the new iPhones are quicker, many of the tasks I performed on the older iPhone are so much faster now.  But then again, when you let almost 3 years pass before updating hardware, it will be faster since hardware technology changes so fast today.

Here is some test video from the iPhone, the video was shot, trimmed, and uploaded all from the phone.  Even though the iPhone records in 720p HD, the process (without iMovie) compresses the video BEFORE uploading to youtube, hence there is no HD on the sample video here.  I guess that can be expected when uploading using the 3G connection, AT&T does not want all kinds of HD video clogging up it’s already stressed network.  Will try iMovie for the iPhone sometime soon and see what happens.

Here is the same video, I used iPhoto on the Mac to “copy” off the .MOV file then uploaded this version to youtube.  As you can see this video has the HD option and is a bit clearer when you switch to the 720p setting.  The raw .MOV file details are:  1280×720 res, 24fps,  AAC mono 44.1kHz, 10.4 mbits/sec.

BTW, the iPhone was held in the tripod using the ProPrompter Wing hardware.

Overall, the HD video will be nice for on the fly video recording, replacing the Flip HD we have.  Moving up to GPS is a plus, and it looks like we are going to enjoy our new iPhones once we have cases that fit well.

– Dom

Improve your video audio by turning off AC/DC power

June 14, 2010 Leave a comment

In my Audio & Video learning over the years, I discovered this little nugget to improve audio quality when recording video.  I’ve only recently remembered to create a video on it.

Here is my setup:  Sony HDR-SR11 HD video camera with a 1/8 microphone input, an unbalanced lapel microphone with a 1/8 mono connector, & the AC/DC power cable for the camera.  This is a general problem with unbalanced microphones and when transformers are in close proximity.  Take a listen to the video to see the improvement in action.


– Dom

* For better video & audio quality watch the 720p HD version.

700 MHz Wireless Microphones

June 2, 2010 Leave a comment

The FCC recently reminded people (on 5/28) in the United States that there has been a change in spectrum allocation to avoid interference.  On June 12, 2010, wireless microphones and monitors will no longer be able to be used in the 700 MHz band (specifically698 to 806 MHz).  Here is the PDF on the FCC website.

What this means, is those individuals/groups who use wireless microphones for audio capture for video, screencapture, or podcasting, in the above bandwidth will start to receive noise and non-ideal audio as new 4G consumer devices are deployed in proximity to the wireless microphone.

The solution for the vodcasters/screencasters/podcasters is to either replace the wireless microphone or work with the equipment manufacturer to get the wireless radio inside the transmitter & receiver changed out to operate on a frequency outside the 700 MHz band.  Some manufacturers have a trade-in or rebate programs to help people with this change.

Here is another helpful link on the FCC website which lists known wireless microphones in the 700 MHz band.

Now, if by chance you live on a Indian reservation away from any mobile or cellular phone service, your wireless microphone should work just fine after June 12, 2010.  🙂

– Dom

%d bloggers like this: