Recording Tips and Techniques

What Does Phase Mean In Audio Recording?

December 17, 2012 by Ken Leave a Comment

Phase is a pretty importance concept in audio recording. It affects how different sounds – like instruments, voices, etc. interact with one another. It also affects how the same wave interacts with other versions of itself, created by delay effects or by room reflections when it comes out of a speaker and bounces off the walls and ceilings.
So what is phase? First it’s important to remember that sounds are waves, like the one in the picture on the left. These waves are made by air molecules being pushed around. That red line across the middle of the wave in the picture represents silence – no air molecules vibrating. The peaks on the top part of the graph are the positive pressure parts of the sound wave, made when air is being pushed into or toward a microphone. The bits underneath the red line are the negative waves made by air moving away from the microphone. I talked more about this in the recent article – Using The Polarity Switch To Optimize Live Drum Sound. Whether a wave is positive or negative is its polarity. I mentioned in the Polarity Switch article that the term phase is often mistakenly used in place of the term polarity. So now that you know what polarity is, you’ll understand after this article why phase and polarity are often conflated.

So what is Phase?

Phase is about the relationship between two or more waves. So if we had an exact duplicate of the above wave playing at the same time, they would be in phase, and the amplitude (how high or low the wave is) would be doubled. If this same duplicate wave were moved in time, however, by just the right amount (that is the red one in the lower picture to the left), then the two waves would be completely out of phase with one another and the amplitudes would cancel each other out. Of course any difference in timing between these two identical waves would be considered out-of-phase (just not “completely” our of phase) and some cancellation would still happen.
If wave number two (the red one) were now to have its polarity “flipped” (reversed), it would be back in phase with the first wave. Get it?
Now imagine different types of waves from different sound sources all playing at the same time. If you’re not careful, certain sounds might combine to cancel out some sounds and increase others. We can use things like time delay, EQ, and the polarity switch on mix channels (usually mistakenly called the phase switch) to help us deal with phase issues.
Here is an excellent article that goes into more detail about phase and how it concerns recording and mix engineers:
http://www.prosoundweb.com/article/in_the_studio_techniques_for_dealing_with_phase/

Getting a Music Mix To Sound Good No Matter Where It's Played

December 15, 2012 by Ken Leave a Comment

A very common and serious problem for people recording and mixing music in home studios is that the recordings don’t sound the same on the big CD player/entertainment center as they do on iPod earphones, and different again in the car. This can be really frustrating when it sounded so great in the room where you mixed the music. I wrote an article about why this so often happens called Your Ears Are Lying to You – Why Your Song Sounds Great in Your Room, But Not in Your Car.
The big culprit is almost always a less-than-ideal acoustic situation in the mixing room. First, these rooms are usually coverted bedrooms, which are notoriously bad, acoustically. Their boxy shapes with flat and parallel walls create lots of havoc with sound waves, adding energy at some frequencies and removing energy from others. So if you add and subtract volume with EQ, it may sound great in that room, but terrible somewhere else. That’s because the EQ was compensating for the bad acoustics in the room.
Another problem for the home recordist is that monitor speakers are usually not that great either. Some folks don’t bother with them at all, mixing instead on headphones. Bad idea! Mixing and mastering in headphones is universally frowned upon because music sounds much different through the air than in headphones and again, you get a non-portable mix – one that won’t sound the same on different systems. Likewise using your computer speakers is not a good idea because if they are “good” speakers, they’ll have been designed to complement the sound, meaning they make the things sound better than they really are. If they are average computer speakers, they’ll simply be incapable of accurately reproducing accurate sound across the spectrum. So you need to invest in a decent pair of monitor speakers.
Lastly, a lack of knowledge about frequencies can create a poor mix. If you have taken care of the stuff above – treated the mixing room or designed an ideal space, and gotten good monitor speakers – most things will take care of themselves and you don’t need to be an expert in all the frequency and sound-y science. However, if you don’t or can’t have that awesome mixing space, having at least a rudimentary knowledge of that stuff, AND being very aware how the bad space can and will affect your mix, you can take measures to counteract the problems. In my case, I will make a mix and then take it downstairs with a notepad and write a lot of stuff down when listening on the “big” system. Then I’ll take the mix into the car and drive around doing the same thing. Though you should pull over when writing your notes:). Finally I take all the notes back to the mixing room and make corrections. Then I do the process all over again. Yes this takes longer, but it’s worth it, especially if you can’t afford to acoustically treat your room or buy good speakers.
Here is an article with several tips for treating and buying speakers and for mixing to create a portable mix.
http://www.loopblog.net/tutorials/music-production/studio-techniques/mixing-a-track-tips-getting-your-mix-to-translate-well/

What Is A Delay Throw Effect?

December 13, 2012 by Ken Leave a Comment

One of the many common effect used primarily in music is called a delay. It might help if you call it an echo, because what a delay does is create a copy of part or all of a piece of audio and then repeat it just after the original. It “delays” the repeat by some set amount, usually a fraction of a second.
Now you can attach this effect to an entire vocal track, or you can just treat a single word or phrase in the track. The latter is called a “delay throw.”
So how that would sound is that the audio – let’s say a vocal – would be merrily singing along with no echo (delay). But then at some specific point in the song, maybe right before a chorus to build up anticipation or some other emotional effect, you decide to apply the delay effect to just one word or a short 2-3 word phrase.
In the following video by Dezz Asante, he shows you how to do this using Cubase recording software. Of course you can do the same thing in other DAW (digital audio workstation) programs. In Reaper there a several ways to do it. You can use an effect buss and an automation envelope line like Dezz does in the video. But in Reaper I would be more likely to slice out the audio I want (Shift-Ctrl-S) to create a new audio item, and then simply insert the delay effect onto the new item.
See the aforementioned video below:

Keeping The Electric Guitar Out Of The Way Of The Vocal

December 8, 2012 by Ken 2 Comments

Peek-Through In a rock song, you want powerful and up-front electric guitar – that’s what rock is all about, right? Unfortunately electric guitars and voices usually occupy the same spot on the frequency spectrum around 3 KHz. So the guitar often overpowers the vocal. Well, when we’re mixing, if we want to turn one thing down in relation to another (that’s what mixing is all about, right?), we can just move a slider on, say, the guitar track until it’s low enough that the vocal can be heard clearly. The only problem is that by the time you get a clear vocal all the way through the song, you’ve turned the guitar down too much for it to be punchy and powerful.
Of course you can use EQ to reduce the guitar’s frequency at around 3 KHz, which will help. But what if that isn’t enough? It often isn’t. Well that is where “ducking” comes in (which can be used for any and all instruments – not just guitar of course). See my article on ducking here: What is Ducking In Audio Recording?, where I show you how to do ducking in Reaper recording software. This technique uses a compressor to automatically push down the level of the guitar (or any instrument track), but ONLY when the singer is singing. You could do this manually if you are very, very patient. I highlighted an article earlier this week showing you in a video how to do this in Making The Vocal Track Sit Well In The Mix .
Here is an article by Bjorgvin Benediktsson, complete with audio examples, that talks about “side-chain” compression (the way you make ducking happen) to get the guitar out of the way of the vocal in a rock mix:
http://audio.tutsplus.com/tutorials/production/how-to-use-side-chain-compression-to-make-rock-guitars-stay-out-of-the-vocals-way/

Some Important Tips For Mixing Music

December 6, 2012 by Ken Leave a Comment

Teacher with audio recording tips on blackboard There are as many tips for mixing music as there are people who mix music, but a few of these tips are common to just about anyone who has spent any significant time mixing. Joe Gilder just put out an article about the mixing lessons that were most significant to him in 2012, and not surprisingly, some of these universal mixing tips were on there.
One of the items on his list – the mix is slave to the recording – could be the most important lesson in his list, and was interestingly, the topic of the post I wrote yesterday – A Lack Of Passion In A Performance Can’t Be Fixed By Effects, But… which states that it is far better to get good tones, levels and performances while in the recording stage that it is to try to fix them in the mixing/editing stage.
Another of Joe’s tips is something I always, always, always (getting the idea?) do, and that is to test your mix on crappy speakers. In my case I usually do this in the car while driving around in traffic, where a good chunk of my audience will be listening to my music. The point of this is to ensure a portable mix, one that sounds good on any system it’s played on. If your mix has flaws, these crappy speakers will often highlight them better than your “good” speakers. This is doubly important if you do your mixing and mastering in a less-than-perfect acoustic space.
For the rest of the tips on Joe’s list, see his article here:
http://www.homestudiocorner.com/2012-lessons/