Creating depth: The Haas effect

The Haas Effect


The Haas effect or the Precedence Effect is a Psychoacoustic Effect described by Helmut Haas as the ability of our ears to localize sounds coming from anywhere around us.

In short, our ears determine the position of a sound based on which ear perceives it first and its successive reflections (arriving within 1-35 ms from the initial sound) which, will give us the perception of depth and spaciousness. Pretty simple!

In general, we use our pan knobs to position sounds within the stereo field. Lets discuss panning briefly… If we have a sound coming out of a stereo pair of speakers at an equal volume, our ears will interpret that the sound is coming out from the middle. So, panning is not much more than the amount of volume you send to each speaker…  Let’s remember that our ears depend on not only volume, but also on time and frequency differences for the localization of sounds.


The Haas Effect – How To

The concept of the Haas effect can be applied in order to get a wide, open and spacious sound resulting in a more realistic sense of depth. In our example, we’ll use a stereo-delay plug-in to achieve this effect. There are 3 things to remember:

1) Set the delay time on the side where  you want to perceive the sound is coming from to ‘0’ (no delay)

2) Set the delay time on the opposite side anywhere from 1 ms – 35 ms. Solo your track and  increase the delay time starting from ‘0’ and listen!

3) Watch for a possible loudness increase since you are converting your mono track into a stereo track when you insert the stereo delay plug-in. My suggestion would be to set the ‘MIX’ control on both sides of the stereo-delay  to 50%. Adjust your track volume accordingly.


The Haas Effect – Example

Listen to the following audio examples using the Haas effect technique in two mono guitar parts.

Both guitars panned center:

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Guitars panned L50-R50:

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Haas effect concept; a stereo delay plug-in is inserted on each guitar track. See pictures for settings. Notice that the settings are exactly the same but applied accordingly (inverted) on each side.

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Haas Effect

Haas Effect

As with anything in mixing, experiment using different settings and tweak different parameters until you get the desired results. Choose only one or two instruments that you feel should sound open and spacious and apply this technique. Overuse could result in an unfocused stereo image.

If you want to download the files and import them into your DAW, click here




    1. Hello Randy! It is nice to see you around here:-)

      Love your point. I meant to say in this article that if you are concerned about comb filtering and how it all translates into mono, you should double-check and adjust your settings while monitoring going back and forth into mono.
      In general, there is a higher risk of running into comb filtering issues when using delay times shorter than approximately 20 ms. You can also increase comb filtering if you insert your stereo effect into your mono track, apply the Haas trick and then try to change your pan pots to other than hard L&R; which, will defeat the whole purpose of using this trick anyway!
      Yes, lowering the level in the late channel definitely helps prevent comb filtering as well but, keep in mind it will reduce some of the sense of depth we are after by using this technique. So, I’d be careful when adjusting my mix levels within the effect itself for that reason.
      A good listening environment or a good pair of headphones will help you detecting whether you are helping your mix by trying to create depth using the Haas effect.
      I didn’t run into any comb filtering issues at all while mixing the above provided examples. Always check your mixes at the end using a spectrum analyzer as well as converting it into mono!
      And most important…use your ears!

      Again, thanks for your comments!
      God bless

    2. This explains a lot Randy. I used to track guitars using two amps with one delayed anywhere from 10 to 35 ms. Stereo track automagically. If I knew they were going to mono my guitars I would automatically take that out to 50-100ms and lower the level. I didn’t know why it sounded better. I just knew it sounded “box-ey” if I left it between 10-35 and they ended up mixing the guitar to a mono track.

      Years ago I recall I used a long delay on a song for volume swelled chords. Since the delay and guitar were separated by hard pan, the engineer who traced it, panned hard left/right during the tracking date. Later I came back to hear some mixes and someone had dumped the delay channel and they didn’t do anything to compensate so all the wonderful delay swells were gone. Ouch!

    1. Hello Kawentzmann!

      As explained in this article, the late channel (also known by some engineers as the ghost channel) should be slightly different than the original sound. And this is all because high frequencies travel shorter distances than low frequencies. Therefore, our ears will perceive a signal with less high frequency content as being farther away…
      Let’s always remember that our ears use not only volume to localize sounds. Time and frequency both play a BIG role in identifying where a sound is coming from.
      If you take a look at the pictures above, the plug-in has a parameter called LPF which stands for Low Pass Filter. Notice that it is set to 10K in the ghost channels. What that means is that we are knocking off all frequencies above 10K resulting in a darker sound coming from that side, thus, giving us the impression of distance and depth.
      As of a reflection having different transients… Any changes in frequency content will affect your transients so, that’s a given once you apply the LPF.
      Good question! Keep ’em coming:-)

        1. Thanks Kevin! You know? I have learned that there is so much more than just theory to the art of music production in general. And, there’s no better way to learn than discussing stuff in a community like and simply learning from each other. I have read all kinds of books and even went to college, visited just about every blog out there on the web etc. but, it wasn’t until I took my Mix-Like-A-Pro course with you that I realized nothing replaces learning from someone with the experience and desire to teach others. So, as I continue to expand on the things I’ve learned, I realize nothing replaces sharing knowledge when you’re learning such a subjective art form. So, I truly look forward to sharing more from my own experiences in this journey as a recording/mixing engineer with the hopes that it will help somebody out there… Thanks for the opportunity!

  1. Instead of using a stereo delay why could’nt you just duplicate your track, pan them left and right and then use the delay offset on one of the events to delay it by up to 7 ms?

    1. Hello Paul!

      The method you advice is a nice way to ‘stereorize’ a mono track and a very useful trick indeed!

      However, in our discussion here, we were after not only ‘stereorizing’ the track but adding some sense of depth as well. You limit yourself in that regard if you just delay the duplicated track. You’d still need to at least insert a LPF in the delayed track and roll off some top end to create the effect we’re trying to achieve as the title implies. As a bonus, using a stereo delay at its most basic level still gives you other extra parameters to play with such as rate, feedback etc in case you were curious and tried to get more creative.

      It really depends on your workflow and what you’re trying to achieve.

      Thanks for commenting!

  2. OK, say I have a mix with the focus being the guitar ( finger picking), and the vocal. Is it possible to use this effect to make it so it sounds like there are 2 different guitars playing the same thing,one comming from the left and one fron the right, set back in the mix? Or would that automaticly turn mono being that the same thing is being played on both sides? I hope I’m making sense as I don’t know how else to describe it! How would you treat a senerio with just a vocal and guitar?

    1. Try this.

      Mult your Gtr channel.
      Pan one hard right, one hard left.
      Put an eq on each side.
      BOOST one side by 2 or 3 db and CUT that same amount on the other.

      Try different frequencys. But start at 1k

      Report back! 🙂

    2. Hello Paul and thanks for coming back!

      The style of music you’re working on will have an impact on how you want to treat a voice and instrument in a sparse mix such as the scenario you are bringing. Say you have a song like say… Radiohead’s Exit Music (For A Film) and then you listen to something like Tuck & Patti… Two totally different approaches!

      Kevin’s advice on duplicating the track and cutting/boosting the same frequencies on the opposite sides is a good way to ‘stereorize’ your guitar sound, and make it sound bigger. On the other hand, if you wanted to actually widen the guitar overall image so it sorrounds the voice in the middle, you could still try the delay trick with slight different times on each side, you’ll see how it does open up the center while keeping its focus.

      Try this:
      1-Assuming you have a mono guitar track and a mono vocal track, insert a mono-stereo delay in the guitar track. Set the delay time as follows: Left 1.5 ms & Right 0.5ms
      2-With your guitar & vocal track panned center (guitar stays hard L&R) toggle your bypass on/off and see what it does for you… try different time settings if needed until you get the sound you want.

      Don’t forget you can also add some reverb to set the back to front perception you are looking for…

      In conclusion, I truly believe that there are different options depending on the style you’re working on and…needless to say how your tracks were recorded in the first place- 1 mic or a stereo pair, maybe the combination of guitar mic and a room ambiance mic, etc…?

      Let us know if some of these work for you, if not, we can explore other ways:-)

      God bless!

  3. Thank both of you for your advice! I will try these tomorrow as I just got done with a hard day of work. I too, want to thank you for what you are doing here! May God bless you also.

  4. OK! Now it’s sounding alot fuller! Thank you very much! Would it be possible to send you a song (wav file) so you could maybe give a listen and give some feedback, and if so how? I am putting the finishing touches on a song I wrote and would like a professionals opinion.Thanks again.

    1. Hello Jon!
      I personally apologize for the late reply. I didn’t know this comment had gone unnoticed since I’m no longer part of MixCoach.
      By now you have probably already figured how to switch to mono in PT. But I’ll go ahead and answer in case someone else has the same question. I’m still happy working in Pro Tools 9 and the simplest way (and free!) for me is to put the AIR Stereo Width plugin (it comes with PT!!) found under the Sound Field plugins category.
      1- Simply set the Width to 0% .
      2- To switch back to stereo simply bypass it.

      That’s it!
      Thanks and God bless,

  5. Hello all,
    A great and a very informative article on the audio engineering. As i’m new to the respective discipline i am relying more on the self learning.
    One thing which i’ve not been able to figure out is that even by panning both the L-R channels by 50% would make no difference. as they’re having the same ratio of 1:1 the same which they have on 100% pan levels to both the channels.
    Then why will we pan both by 50% ?
    Please reply to my question 🙂

    1. Hello Ali!

      I appreciate your comment and thank you for your kind words. As you may have noticed I’m no longer part of the MixCoach community but I’ll do my very best to help answering your question.
      After listening to the audio files above, I noticed that somehow they were changed and all 3 examples play the same file which I believe is the one with the gtrs panned center. Not sure how that happened but I’m not surprised, stuff like that happens;-)
      Anyway, you won’t hear any difference, and that kind of explains your concern.
      Best thing to do would be to try the suggestions in the article and see if it works for you. Otherwise, feel free to contact me directly and I’ll do my best to help!

      All the best,

  6. Yep, I double checked my original sound clips that I had submitted to MixCoach and these here somehow got changed defeating to whole purpose of showing what the effect sounds like in context.
    I personally apologize for any inconvenience this may cause. I’ll contact the super dynamic team over at MixCoach and I’m sure they’ll be able to fix it. Otherwise, I’ll have the post removed!
    Thanks everyone!

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