Hack3.4.Mix Your Podcast in Hardware


Hack 3.4. Mix Your Podcast in Hardware

Mixers can look intimidating at first, but they are actually easy to use and very powerful.

Mixers are an inexpensive way to get your audio close to broadcast quality, with no digital editing. Figure 3-7 shows the Behringer UB1202 mixer.

Going from left to right on the setup you can see a number of horizontal strips. These are called channels. This mixer has an amazing 12 channels in it. The first four are mono channels capable of taking XLR [Hack #12] inputs. The XLR input of the first channel is highlighted in the upper lefthand corner.

Moving down the channel you can see a set of three knobs. This is a simple three-band equalizer [Hack #57] that can boost or reduce the low, middle, and high frequencies on the channel. This is great for getting rid of high-pitched noises, adding some presence to a person's voice, or removing low hums.

Figure 3-7. The Behringer UB1202 mixer


Below the equalizer section, the next highlighted knob is the pan control. The pan positions the signal in the stereo space from left to right. By default, it's in the middledead center between the two channels. If you are recording two microphones and you want the output to be stereo mixed, you will want one to go slightly to the left and the other to go slightly to the right. This gives listeners a sense that they are at the table with the two people who are talking.

Right below the pan is the master gain for the channel. With this, you can boost or lower the amplitude of this channel relative to all the others. For a person with a soft voice you will want to boost it up, and for a louder person you should turn it down. The process of making small gain adjustments throughout the session is called riding the gain [Hack #56]. Another possibility is to use a compressor to manage the signal levels. More-expensive mixers have compression built right in as one of the effects.

All of the channels flow from top to bottom and from left to right. Inputs go in the top, flow through the channel to the channel gain at the bottom, and then go from left to right to the master gain on the far righthand side of the mixer.

The master gain is the slider with the rows of LEDs above it. The LEDs show your signal strength in real time. Moving the slider up will increase the gain of the entire mix. Moving the slider down will soften the entire mix. On a bigger unit, the channel gains are also manipulated with sliders.

The UB1202 also features several outputs. You can use two XLR output plugs at the back of the unit to connect to your USB preamp. You can also use the control room and tape outputs to go directly to the line-in of your computer or MP3 recording device.

If your microphones [Hack #13] are continuously soft, you will want to use the channel pregain knob, which is directly below the XLR channel input. This will boost the signal before it goes into the channel.

Some mixer models have built-in effects [Hack #58], though this one does not. These effects can provide reverb, chorus, flanging, compression, and a whole host of handy signal processing. For podcasting, you will likely want to use some compression to ensure that signals don't clip, and a slight reverb to add some vocal depth and sense of space.

If you plan to edit the recording digitally, you should keep the signal as clean as possible. I recommend using just the compression feature. The value of hardware compression is that you will keep the signal from clipping when it's converted from analog to digital either at the USB preamp or at the mic-in or line-in port. Software compression is good, but it can't fix a signal that's already been clipped by the analog-to-digital converter. It's best to have a hardware compressor to ensure that you never clip in the first place.

Even for a person who likes twiddling with knobs, a mixer can be intimidating. Here are three rules to live by:

  • Don't tweak more than one thing at a time without checking what happened right after you tweaked it.

  • If you find yourself in a completely messed-up state, just reset everything to its center or default position and try again.

  • Tweak the knob to its full amount first. This will give you a sense of how far you can go and will allow you to dial it back in to find the right setting. If you are familiar with cameras this is similar to the technique of proper focusing; focus far out and then dial it back in to find the right detail point.

Here's one last tip from a father of a young child: keep your mixer away from the edge of the counter, and off the floor. Kids love to tweak those knobs and change subtle settings.

A mixer is an important component of your setup, as it drives your microphones and gives some initial processing to the signal to keep it loud, but not so loud that it clips. A mixer is essential if you plan to skip a USB preamp and go directly to the line-in or mic-in of your computer.

3.4.1. Mixers

When I think about a recording studio, I envision an engineer sitting in front of a gigantic mixer with hundreds of knobs and sliders. The mixers that are in studios can and do cost millions of dollars, but a mixer for home studio use can cost surprisingly little, in the $100 range, in fact.

Table 3-7 shows some of the portable mixers that are available on the market today.

Table A selection of portable mixers

Manuf.

Model

Stereo in

XLR in

Effects

Phantom power

Computer interface

Price

Behringer

Eurorack UB802

4

2

 

X

 

$59.99

Behringer

Eurorack UB1202

6

4

 

X

 

$99.99

Soundcraft

COMPACT 4 Mixer

2

2

 

X

 

$109

Behringer

Eurorack MXB1002

1

5

 

X

 

$119

Nady

MXE-612

4

2

 

X

 

$119.95

Yamaha

MG10

2

4

 

X

 

$129

Alesis

MultiMix 6FX

2

2

X

X

 

$149

Nady

MXE-812

4

4

 

X

 

$149.95

Tapco

Blend 6

2

2

 

X

 

$149.99

Peavey

PV8

2

4

 

X

 

$155.99

Yamaha

MG8

3

4

X

X

 

$199

Alesis

MultiMix 8USB

2

4

X

X

USB

$199

Yamaha

MG12

4

4

X

X

 

$319

Alesis

MultiMix 12USB

4

4

X

X

USB

$399

Mackie

1202-VLZ Pro

2

4

 

X

 

$489

Mackie

1402-VLZ Pro

4

6

 

X

 

$659


The table is organized by price to illustrate how the number of channels and effects can vary as you go up the price scale.

Here is what the columns mean:


Manufacturer and model

The name of the manufacturer and the model of the mixer.


Stereo in

The number of stereo channels. Mixers have two different types of channels. The first is a mono channel that takes XLR inputs. The second is a stereo channel that takes 1/4-inch inputs for left and right, and can be used as either a stereo channel or two mono channels. For pod-casting you will be using the mono XLR input channels for your microphone.


XLR in

The number of mono channels with XLR inputs.


Effects

There is an X here if the mixer has some built-in effects that you can apply to the signal. These effects usually include chorus, reverb, and flanging, among others. Many software packages can simulate the same effects on your computer, so this feature might not influence your purchase.


Phantom power

All the mixers listed in Table 3-7 provide phantom power. I listed it in the table because it's so important to ensure that your mixer has this feature so that you can use condenser microphones. Small DJ mixers often don't include phantom power because they are meant to be used with cheap dynamic microphones. For high-quality podcasting, condenser microphones are necessary, so make sure your mixer provides the phantom power these microphones need.


Computer interface

In a few cases, the mixer can record signals through a computer interface [Hack #12]. The standard of the interface is listed in this column. Though the ones in this list support the USB standard, some higher-end mixers, such as those from Mackie, have plug-in FireWire cards for control and recording.


Price

The list price of the mixer in U.S. dollars. It's easy to find deep discounts on the Web if you shop around.

If you are going on the road you can take one of these mini-mixers with only two or four channels and have the output go into an iRiver MP3 recorder [Hack #69] or a Marantz portable recording unit. An example of this low-cost approach is the Beercast [Hack #30], which uses an iRiver, a mixer, and a few cheap microphones.

A mixer is handy in several situations. When you have more than two microphones you can use a mixer to fit them all into two channels, and you can set the gains and filtering parameters on a per-microphone basis. When you are recording phone conversations through a telephone hybrid, you will want a mixer to properly route and record the audio coming both to and from the phone.

3.4.2. Microphone Preamps

Condenser microphones [Hack #13] require phantom power to operate. You can get that power in several ways. Some condenser microphones (e.g., the Audio-Technica AT835B) have their own slot for a battery. This is the most direct way. Failing that, you will need to feed the microphone power through the XLR cable. Mixers, USB, FireWire preamps [Hack #12], and some sound cards provide this phantom power.

Another option is to use a dedicated microphone preamp. These devices serve two main functions: the first is to provide power to the microphone, and the second is to have gain control to amplify the signal. Some models provide equalization and other filters and effects to give a clean, warm sound.

Table 3-8 shows some of the microphone preamps on the market, sorted by price.

Table A selection of microphone preamps

Manufacturer

Model

Channels

Phantom power

Effects

Price

ART

Tube MP

1

X

 

$57

Behringer

MIC100

1

X

 

$59.99

Behringer

MIC200

1

X

X

$69.99

ART

Tube MP OPL

1

X

X

$72

ART

Tube MP Studio

1

X

X

$86

Rolls

MP13 Mini

1

X

 

$90

Alto

Alpha MicTube 2-channel

2

X

 

$114

M-Audio

Audio Buddy

2

X

 

$119.95

Behringer

MIC2200

2

X

X

$119.99

Presonus

TubePre

1

X

 

$129.95

Bellari

MP105

1

X

 

$150

Behringer

T1953

2

X

 

$169.99

Studio Projects

VTB1

1

X

 

$179.99

Presonus

BlueTube DP

2

X

X

$229


Preamps directly affect the warmth of someone's vocal sound, and can vary in price from $50 to $3,000. I chose to show the less expensive ones because I think these will work well for podcasts and they provide a nice, phat sound for your voice.

Here are the definitions of the table columns:


Manufacturer and model

The name of the manufacturer and the model name or number.


Channels

The number of input channels. On all of these devices, each input channel has both an XLR and a 1/4-inch input jack, and an output XLR and a 1/4-inch jack. This means you can use the device to convert from XLR to 1/4-inch unbalanced to go to a computer's sound card.


Phantom power

All of these devices supply 48-volt phantom power. It's called out here because it's one of the critical reasons for investing in a preamp.


Effects

Some of these preamps come with built-in effects, besides the gain. These include equalization, output limiting, and more.


Price

The list price in U.S. dollars. You can always find deep discounts on musical gear on the Web if you shop around.

If you plan to conduct interviews, you should invest in a two-channel model that can drive two microphones independently.

Most of the preamps in Table 3-8 are tube preamps that deliver a "smooth and fat" sound. Even if you don't need the phantom power or gain because some other device is providing this, you might want to consider a microphone preamp to thicken your voice and to add some warmth.

3.4.3. See Also

  • "Set Up a Basic Home Studio" [Hack #12]

  • "Set Up a Home Studio" [Hack #61]



    Podcasting Hacks
    Podcasting Hacks: Tips and Tools for Blogging Out Loud
    ISBN: 0596100663
    EAN: 2147483647
    Year: 2003
    Pages: 144

    Similar book on Amazon

    flylib.com © 2008-2017.
    If you may any questions please contact us: flylib@qtcs.net