Pro Mixing Series: Episode two: The Haas Effect
For some of us this may be a very mysterious image: “panning” presets in a delay device of a sequencer DAW…
Well it IS a mysterious image until you check this article about the Haas effect.
Have you ever been so frustrated with a mix that doesn’t have life, wide stereo image and airy, “natural” space? Are you not getting enough depth in your mix? Have you added so much stereo reverb to add “space” to your mix that you end hating what you have done? Well… I have…
It is truly horrible getting every track in a mix sounding so “mono” after panning left and right different lines or instruments. It feels truly like there is something in the way from the original tracking to your final mix. The panning of some tracks helps very much to make a clear mix but sometimes that is just not enough to make things clear and certainly deeper, spacious, open and rich-sounding.
There is a solution to this lack of depth: The Haas Effect . It can take a simple mono instrumental or vocal line and give it presence or take it to the back of the mix, depending on how you use it and what other effects you add to the chain.
Basically, what you are doing with the Haas effect is making the listener’s brain to interpret the sound coming from a certain direction and angle in a way that is more natural to the ear than a simple panning adjustment. The Haas effect takes full advantage on the fact that we have TWO ears.
In real life, when a sound comes from the left it is received by the left ear BEFORE the right ear, so the brain interprets this difference as “a sound coming from the left”. The interpretation depends on how long is the delay between the two ears the less the delay, the more centered is the sound. This very short delay can be interpreted as a phase shift because the sound reaches first one ear and then the other. So, when there is no phase shift, no delay between the two perceived signals together are interpreted as dead center, with no panning at all.
We CAN use this psychoacoustic effect (the Haas effect) to print more depth and directionality into our mixes without even moving the panning control of the console! That’s why I put the snapshots from Ableton’s Simple Delay. You can make your own Haas effect presets in any delay that permits very, really shot delay times and also inserting a time shift between the two channels. The Haas effect is performed delaying one of the two channels (left or right) just a little bit, from a couple of samples to no more than 30 milliseconds (more in depth scientific info in the article from Wikipedia referenced above); the channel that reaches our ear first is the one that dictates where is the sound “coming from”, the later channel is interpreted as the natural tail of the sound.
As illustrated on the image above, the delay we will use MUST support 100% wet and the ability to delay each channel at different times; that is where the true nature of the Haas effect resides, in the little delay we can insert to one channel to widen stereo image and panning illusion.
If your delay does not support 100% wet setting, then it is not suitable for Haas treatment, this is because the delayed signal -since it is a very shortly delayed signal- has also a phase shift respect to the original signal, so phase cancellation will occur if you mix the original and the processed signals and you’ll end up with a strange comb filtered sound instead of the stereo expanded effect (unless this is exactly what you are looking for… you know there are no rules… If your target is the comb filtered sound then go for it).
Good amounts of delay go from just 2 samples (with the right plug-in or device) to 30 ms. More than 30/40 ms results in the brain interpreting the expanded sound as two different sounds coming from left and right, the signal is not expanded anymore, it’s clearly echoed or delayed.
I made a little demo using a mono piano loop, enhanced with a simple delay and a couple of other effects.
(In the making of this little sample I didn’t touch the volume fader or the panning knob)
The loop is repeated four times. The first cycle is the original mono signal. The second cycle is the mono signal with a delay in the left channel of 10ms. The third cycle is the Haas effect enhanced with L/R equalization, higher frequencies are raised in the right channel and lower frequencies on the left channel*. The fourth cycle has some reverb added to get a deeper sound, more “roomy” sound.
It is important to know that the Haas effect can be reinforced by the way you make frequencies reach the ears. The brighter the sound, the more directional it is. Lets put in other way: when you hear a sound from the left the perception that the right ear has of the same sound in less bright because the head is absorbing some of the higher frequencies, that is also caused by diffraction: low frequencies can travel further and around obstacles more easily than high frequencies do. The point is that you can make a clearer Haas effect by making a difference in the spectrum perceived by each ear, so you may leave bright in the “closer” channel and more bass on the “further”. In Ableton Live you can use the Traditional EQ Eight to make a better configuration of your Haas processor. That’s what I did in the third cycle of my piano demo loop. I raised brightness in the right channel and bass on the left, so you get more “room” on the left, expanding the perceived space of the treated signal.
You can check a simple Haas processor I built in Live 6.0.10 and try new settings and tweaks to make it a better one for your goals, this one is quite basic but does the job with just one macro control (Haas panning and spectral difference).
Haas processor Ableton Live 6.0.10 Device Chain
· You can use the Haas phase shift on any signal mono or stereo. Just remember to adjust wet to 100% if you do not want the comb filtering in your audio.
· The less phase shift, the more “centered” is the sound.
· Haas effect can be reinforced with selective EQ on each channel.
· Using the Haas effect with some amounts of lowpass and reverb will send your sound to the “back” of your mix. The more reverb you use in a Haas processed signal the more it goes to the “back” of the mix.
· To get the “in the next room” effect lowpass at 600Hz and add a second delay with a time of 50ms or 60ms with ground 40% wet to make artificial reflections and a reverb to make the sound muddy.
· If you are trying to get the comb filtered sound by setting the wet knob below 100% you have to know that at different delay times different frequencies are cancelled, so explore a little to get what you really are looking for.
Mixes full of depth are the holy grail of home recording mixing, it’s one of those little details that separate amateurs from pros. Make sure you apply this tweak with good criteria. A track by track hard “Haased” song also sounds artificial and hollow, some mono sounds wont be bad at all, you can create huge soundscapes and powerful productions but just don’t overuse this tool if your aim is a natural sounding mix. Of course you can do what you want with your music, just make sure it is what you really want 
0p0::::
September 15th, 2008 at 6:15 pm
Thanks for the nice summary. I had read about Haas before but your article made it very clear.
September 27th, 2008 at 2:27 am
Great article! I’ve just discovered this site, please keep these articles coming.
October 7th, 2008 at 7:19 am
Great article, and very clearly explained. It’s been a pain in the Haas trying to create depth in my mixes, until now.
October 15th, 2008 at 4:52 am
AWSUM READ MATE WELL IN GOOD INFO
November 15th, 2008 at 3:56 am
Sorry mate, but this is a very dangerous practice.
First af all, depth is always achieved from clever use of mono sounds and mono reverbs. Carefully distributed instruments/sounds acros the panorama always do the trick for my mixes. And it`s not even so much about panning as about producing the right type of sound for the mix. The most common problem many people have is that they try to apply lots of effects on their tracks to make them sound bigger, which is completely wrong and gives away their poor programming skills. Which leads to my second argument.
Many experienced producers, including myself, spend hours and sometimes days to create the sound which fits the mix. This takes incredible amount of tweaking on one synth or more, if you decide to employ layering technique, which makes the job even harder, but gives much better results.
What you`re suggesting here, is to use EQ to achive a wider, deeper sound, by boosting/cutting the frequencies which makes stereo separation more evident.
Now, I could maybe agree with cutting, but boosting is something evereone should keep their hands off, and only boost ( especially the low range ) if it`s absolutelly necesarry, and even then, with extreme caution and no more than a few dB.
Sure, what you`re suggesting will sound nice`n`wide, but it will completelly destroy a character of the sound that you may have spent hours to program. What`s more, is that instrument may sound nice in isolation, but when you add it in the mix, you will ruin it`s spectrum. Imagine if you already have an instrument playing somewhere on the left side of the panorama, which contains lots of low frequencies in its spectrum. Then you add your nice`n`wide sound that you have boosted in the low end on the left side as well. What happens? Muddied, distorted sound that overclips and many other nasty things.
So, really, this is one bad idea in a list of all bad ideas you could possibly do with your mix.
If the mix lacks in depth and energy, that is more likely because of poor programming of your instruments, or because of little instruments playing in your mix. Don`t be afraid to add an extra instrument or two, as long as it doesn`t hurt the overal mix. Cleverly pan all your sequencer tracks ( preferably mono ) acros the panorama, and you will achieve the depth you are looking for.
No offence man. Just sharing my experience.
December 2nd, 2008 at 1:14 am
Oh sure man! no worries.
It’s a great add you made to the post. Thanks a lot!
what I intented to make clear about this article was the ability of a little milisecond-delay in a mono signal can make it a very different thing when some one is lacking depth in their mixes.
I’d rather not to treat the soun enyways but not all of us have the studio we dream about or have the money to pay a great recording in a super duper ballroom filled with 3000 bucks mics.
I just shared a little trick. It’s not like I tell everybody to Haas all of their sound, I’ve done it in experiments and I really know how hollow it sounds when everithing goes through the “milisecond-delay”.
Then again thanks a lot for your tips too! they are great tricks when you have the time and the performance and/or synth programming ability
0p0.