Archive for August, 2006

Let’s just back up a sec

Friday, August 25th, 2006

In the midst of my transition from London to Toronto, I am of course reminded of how important backup procedure is in audio as with everything else in the digital sphere.

Just a reminder that with digital audio, as I’m sure with other digital media, it is recommended to make at least 2 copies in addition to the original backup in some hard format like DVD or CD. My new personal method however uses a larger hard drive partitioned into business and personal. My biggest concern with writable media is the unknown shelf life. Any comments?
On a related topic, LaCie has come up with a novel, if nothing else, approach to multiple hard drive using people like us audio engineers know as the brick that patterns itself after the peg and hole lego bricks.

LaCie Brick

From conversations with the fine folks at Carbon Computing in Toronto is that they are pretty but no less noisy than any other drive. Something a rather large firewire cable could remedy.

Hopefully, the downtime from the move won’t be too long. More to come about the audio signal chain.

Mister Mixer

Wednesday, August 23rd, 2006

I’ve drawn up two typical audio signal chain diagrams to illustrate how most people would be recording podcasts. Before getting into the finer points of signal processing, I thought it would be useful to discuss the use of a mixer in this chain.

basic audio signal chain Audio signal flow to record

1) MIXER BASED MONITORING

2) MIXER BASED RECORDING

In the monitoring (1) diagram shown, the audio signal goes from points A/B to Y/Z via the mixer. The mixer is used to amplify the individual input signals (microphone, CD/DVD, etc.) and “mix” them together to go to the main outputs. In many cases, the will be an additional stereo output (left and right channels) used to get the mixed signal to a recording device (2). That record output path will mirror what is going to the speakers (as shown in the diagram).

Mixers are an excellent way to simplify the recording and editing process as the resultant audio file recorded will only be stereo, although this also limits the ability to edit any individual microphone signals in post production.

Chain, chain, chain

Monday, August 21st, 2006

Great song, even greater to the importance of how you record.

Without going into too many details, the audio “signal chain” as it’s known is the entire network of interconnected equipment between your sound source (voice, musical instrument, etc.) and your playback system (headphones, speakers).

What is in between those two points makes all the difference in your final perception of the sound and the recording you are to make.

This week’s posts will be dedicated to each piece of equipment and what it’s doing to improve your sound.

Windsheild/Popscreen or Popsheild/Windscreen?

Thursday, August 17th, 2006

Let’s call the whole thing acoustic diffusion.

Some people have asked me to clarify the differences between a popshield and a windscreen. So I will.

A windscreen is intended to do what it’s name implies; namely preventing the sound of wind from becoming a droning noise in the background of your recording. The windscreen is typified by the “man on the street” reporter and looks like the afro of the microphone world.

Shure A5 8WS Wind Screen
Obviously, not all windscreens are created equal. Differences in foam desities, thicknesses and overall size will impact price but for average use, something like this Shure A5 8WS will work just fine.

The popsheild, or the pop filter, is usually used in a controlled studio envrionment to prevent what are called plosives, ie. P’s, T’s, B’s, etc. So, when I say, “Today on the Program”, you don’t hear the wind noise of either syllable. Popsheilds are usually thin mesh or nylon suspended between a plastic or metal ring, all of which is anchored to an arm that allows it to be attached to a mic stand

Neumann Pop Filter

Above is the buy it from a store solution. More expensive, less hassle.
Here is the popsheild on a budget solution. Less expensive, more hassle.

To remember which is which, think of wind being something that’s outdoors and the sound “POP”. Maybe you can think of a better way to remember :)

Two Hard Drives Walk into a Bar…

Monday, August 14th, 2006

One says, “I’ve had words with that bar keep before.” The other replies, “that guy? He looks tough”. The first responds, “ya, but his bark was worse than his byte”… ouch. Sorry, it was the best I could do this early.

So who needs a separate hard drive in this age of terabytes and 4 GB RAM chips? YOU DO. Why? Because if you’re storing you’re audio on the same drive as your running your programs off of, you are taxing your system more than it needs to be.

The hard disk will be constantly moving between the program data and the audio data it is reading/writing. Adding a second hard drive, either internal or external, depending on whether you’re running a desktop or a laptop, will allow your drive to access information faster on both disks and you’ll run into way fewer CPU overload errors in your recording, or none at all if you’re lucky.
Be sure to get a drive that runs at least 7200 rpm. The disk’s storage capacity is up to you but depending on what you’re recording, podcasts for instance, you’ll likely want to go bigger; 1 minute of wav. quality audio is about 5 MB so just interpolate from there.

Proximity Effect

Tuesday, August 8th, 2006

You know when you meet someone at a soiree and you just wish they’d back off a little bit? They are just too in your face? That’s kind of like “proximity effect”. The phenomenon happens when a more directional microphone, like the cardiod I discussed in my last post, is up really close to the speaker and you get this very “boomy” low end heavy sound. Great if you’re looking for that, but what if it’s affecting intelligability?

Omni-directional microphones, unlike cardiods, can pick up sound somewhat equally in all directions. This makes this polar pattern typical in lavalier microphones or lapel mics. The reception of audio in all directions works to reduce proximity effect and minimize that low frequency boost for a smoother sound across all frequencies.

omni directional polar pattern

Next time you’re looking to invest in a lav mic, think about the polar pattern. Remember that you’ll never make bad sound good, just less bad.

Polar patterns are your friends

Thursday, August 3rd, 2006

This is not a blog about bears in the artic making snow angels. Though I’m sure one exists somewhere.

Polar patterns are a the various directions in which microphones pick up sound. Cardiod or the “heart shaped” polar pattern is typically used in live sound situations because of it’s rejection of sound from one direction and it’s sensativity to sound in the other. This fair degree of “directionality” would allow the microphone to pick up the voice in front of it, while rejecting some of the noise from behind.

cardiod polar pattern

Think of how useful this is when there is a noisy computer fan right beside where you record. You in the front, fan in the back. Less noise! Seemly easy but very useful.

cardiod polar patterns help reject noise
More fun polar pattern “trickery” to come.

Potent Portables - Reflection Filter

Tuesday, August 1st, 2006

In my post Location, location, location, I expounded upon how the environment in which you record can make all the difference to sound quality. Luckily for the individual podcaster, being located in a noisy room doesn’t have to make you cancel your latest show.

SE Electronics has come up with a wonderful device known as the Reflection Filter, that helps reduce room noise without need for a full vocal booth. Through a multi-layer acoustic material process, the filter is able to incrementally reduce noise over a wide frequency range. Well done sE!
sE electionics Reflection filter sE Electronics Reflection Filter