Know How... 66

What kind of microphone is best for you, build your own raspberry pi MAME, how ROMs are made, and more.

Podcasting Mics 101

In this segment, Fr. Robert shows you how to go about choosing the right microphones for your podcasting setup. Dynamic or condenser, XLR or USB, cardioids or omnidirection, you'll be able to get the mic that fits your needs, style and budget.

Mics On Set

Name	Element	Pickup	Address	Freq. Response	Interface	Price
Audio Spectrum AS400	Dynamic	Cardioid	End	80Hz - 12kHz	XLR	~$20
MXL 990	Condenser	Cardioid	Side	30Hz - 20kHz	XLR	~$80
Audio Technica AT2020	Condenser	Cardioid	Side	20Hz - 20kHz	XLR	~$100
Audio Technica AT2020USB+	Condenser	Cardioid	Side	20Hz - 20kHz	USB	~$120
Sure mx391	Condenser	Omnidirectional	Omni	50Hz - 17kHz	XLR	~$130
Heil PR40	Dynamic	Cardioid	End	28Hz - 18kHz	XLR	~$320
Sennheiser ME66	Condenser	Super-Cardioid/lobar	End	40Hz - 20kHz	XLR	~$475

Step 1: Choose your Transducer

The first step in choosing the right microphone is to decide if you need a dynamic or condenser element.

Dynamic Microphones

In a dynamic microphone, soundwaves strike a diaphragm that is attached to a coil of wire. The diaphragm vibrates, moving the coil, passing it through a magnetic field created by a permanent magnet. As the coil moves through the magnetic field, a current is induced within the coil that is an electrical representation of the soundwave. The Dynamic Mic differs from the condenser microphone in several ways. First, it doesn't require phantom power. Second, it is far more rugged: able to withstand physical shock and much higher sound pressures. Third, its frequency response tends to be narrower and curvy: meaning that it will respond to certain frequencies more than others. Pros: Durable Self-Powered Versatile (vocals, instruments, etc.) because it is NOT as sensitive to loudness. High Gain before feedback, which makes them EXCELLENT for LIVE sound Cons: Narrower frequency response range than a Condenser microphone Not good a distant or low volume sounds

Condenser Microphones

In a condenser microphone, the transducer is comprised of a diaphragm and an electrically charged backplate. As soundwaves vibrate the diaphragm it changes the electrical field generated by the backplate. That change in the field is an electrical representation of the soundwave. Microphones that use condenser transducers typically have a flatter frequency response than their dynamic counterparts. This means that you get more accurate sound production across the entire range of frequencies, from vocals to woodwinds to strings. The construction of a condenser element brings with it two important differences from a dynamic element. First, a condenser mic requires "phantom power" – typically 48-52 volts that must be provided by a pre-amp, the mixing board, on an integrated power source. Second, a condenser microphone is more fragile that its dynamic counterpart: physical blows to the microphone can permanently harm the audio qualities of the mic, as can too much sound pressure. (screaming into the mic or placing it too close to percussive instruments.) Pros: Wider frequency range CAN provide a higher quality audio signal Good for studios with controlled audio environments Cons: FRAGILE Sensitive to loudness Requires external power

Step 2: Choose your Mic Addressing and Polar Pattern

"End Firing" vs. "Side Address"

Mics can be either "End Firing" (in which the membrane is parallel to the microphone body) or "Side Address" (in which the membrane is perpendicular to the microphone body) – USALLY, but not always, side address microphone have larger diaphragms than end firing microphones. Large Diaphragm Microphones (LDM) provide "deeper" sound. It "warms" the sound of whatever it's recording Small Diaphragm Microphones (SDM) and best for wide frequency response and "fast" sounds (strings).

Polar Pattern

The "polar pattern" of a microphone is the "pickup pattern": a pattern that describes the different sensitivities that a transducer will have to sound generated in the 360 degrees surrounding the microphone. http://en.wikipedia.org/wiki/Microphone#Microphone_polar_patterns Most mics used in podcasting will have a cardioid polar pattern, but there are opportunities to use omnidirectional, supercardioid, and bi-directional polar patterns.

Step 3: Choose your Interface & Price

There are really only two interfaces you should consider for your studio mics, XLR and USB. XLR interfaces use balanced cables, allowing for long runs with very little interference. XLR interfaces are standard throughout the pro-audio world, meaning that an investment in a XLR microphone will most likely last you through the growth of your podcast. If you think that you want to use a mixer to mix together multiple audio streams, you will DEFINITELY want to use XLR mics. USB Microphones like the AT 2020USB+ and the BlueMics Yetti are popular because they are quiet, easy to use and portable. They include a A/D (analog to Digital) converter within the microphone body, meaning that you don’t need a XLR-USB converter or a mixing board with computer output options. However, there are very few USB microphones that allow for multiple sources on a single computer.

Raspberry Pi M.A.M.E.

TD and editor extraordinaire Bryan Burnett was building himself a MAME (that stands for "Multiple Arcade Machine Emulator") with a Raspberry Pi. This setup will work fine on either the 256MB or 512MB Raspberry Pi. Bryan tried this project with both models and they both work well. The RetroPie Project has a lot of different emulators available, but he focused on the NES, SNES, and SEGA systems.

Materials list

Software

• Cyberduck
• TextWrangler or Notepad++

Parts List

• Raspberry Pi (512) Model B
• Pi Case
• 8GB SD Card
• USB SNES Controller
• Keyboard
• Mouse
• Monitor
• HDMI Cable

Step 1 Download & Install

Download Retro Pi image from PetRockBlock.com. Then make a bootable SD Card and extract Retro Pi. For a Mac, Bryan used the guide over at AllTheWare. If you've got a PC, you'll need WinDisk32 Imager. Once you've made a bootable SD card, place it into Raspberry Pi and boot up!

Step 2 Boot Raspi and Set Up Emulation Station

When you first turn on Emulation Station you'll have to map your controller. After that, exit out to terminal so you can set up your global emulator settings. To set up your controller type the following in the terminal: cd RetroPie/emulators/RetroArch/tools ./retroarch-joyconfig >> ~/RetroPie/configs/all/retroarch.cfg

Step 3 Raspi Config Setup

We're not done configuring things. Next up, go to terminal and type the following: sudo raspi-config At the Raspi Config window select the second option "expand_rootfs" and then press enter. You will be presented with a message saying "partition will be resized." In the Raspi Config Menu select "memory_split." If you have the 256MB Model A enter "128" into the field. If you have the 512MB Model B enter "256" into the field. Then exit to terminal.

Step 4 Update your Pi

Type the following into the terminal: cd RetroPie-Setup sudo ./retropie_setup.sh Update script Update binaries Run Binaries-based Installation **This can take awhile!**

Step 5 Move your ROMs and Edit your Config Files

Bryan found it easiest to FTP into the Raspberry Pi to get his ROMs on to the device. On the Pi, go to terminal and type "ifconfig" to find your IP address. Then use your favorite FTP client to move your ROMs to the Pi. Bryan used Cyberduck on the Mac to FTP. If you're using Cyberduck, here's what you do. Go to quick connection. Select SFTP. For server number, type in the IP address you got from your Pi. The default username is "pi" and the default password is "raspberry." Then navigate to RetroPie / Roms. Transfer ROMs according to folders. Bryan also moved all of his unwanted emulators to a new folder he created called "Unused." When you fire up Emulation Station, you won't see the emulators in that folder. Navigate to RetroPie / Configs / all Then find retroarch.cfg open in text editor. If you've got an SNES controller like Bryan and want to set it up just like he did, check out his configuration file here.

Step 6 Making things pretty

Go to Terminal and type in the following: cd RetroPie-Setup sudo ./retropie_setup.sh Run ES-scraper. It will grab box art and game descriptions so you'll have a nicer looking menu. However, ES-scraper isn't perfect, so you can clean up any incorrect information. To correct your library, use Cyberduck again to download the gameslist.xml file located in the Rom folder. Then you can open the XML file and edit titles,descriptions and images.

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