Free Haa5 Stereo Control Effect By Apex Audio Technologies


Apex Audio Technologies has announced the release of Haa5, a free (pay what you want) stereo widener effect in 32-bit VST/AU plugin formats for Windows and Mac OS X based digital audio workstations.

The plugin takes advantage of the “Haas effect” to enhance the stereo image of the processed audio signal. Haa5 can be used to process both stereo and mono audio signals, whereas mono audio material on the input will be converted to stereo on the plugin’s output.

See also: Best Free Stereo Widener VST/AU Plugins!

I’ve tested Haa5 on several different audio sources and it works rather well as a simple but surprisingly effective stereo widener effect. The GUI has only three control parameters (effect amount, output volume and output panning) and the plugin is very easy to use. It can successfully convert mono signals to stereo and it also does a pretty good job at further widening audio signals which are already in stereo. Even at the maximum width setting, the widening effect sounds fairly natural, similar to subtle chorusing.

It’s worth noting that although effects such as Haa5 can work great for adding a sense of width to mono audio signals (they work particularly well on electric guitars and synthesized leads), caution is advised because artificial stereo widening can lead to all sorts of phase cancellation issues if the processed signal is played back in mono. Always check your mix in mono when playing around with stereo widening tools and make sure that everything sounds sufficiently good in mono before rendering your final mix. And if you’re wondering why the hell should one need to worry about the mono mix in this day and age, the simplest answer is that most club sound systems, as well as portable devices such as mobile phones and tablets, are still mono. Also, the general rule of thumb is that if something sounds good in mono, it will sound even better in stereo.

Haa5 is available as a VST plugin for Windows and AU plugin for Mac OS X, but unfortunately it will only work in 32-bit plugin hosts. Hopefully, the developer will release a 64-bit version of the plugin soon! Haa5 is certainly among the better stereo widener effects out there and also a rather promising first release by Apex Audio Technologies.

UPDATE: Haa5 has been updated in the meanwhile and it now works without any issues in 64-bit plugin host applications. This is great news!


Haa5 is available for free download via Apex Audio Technologies (5.4 MB download size, ZIP archive, 32-bit & 64-bit VST/AU plugin format for Windows & Mac OS X).

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About Author

Tomislav is a music producer and sound designer from Belgrade, Serbia. He is also the founder and editor-in-chief at Bedroom Producers Blog.


  1. “most club sound systems, as well as portable devices such as headphones and tablets, are still mono.” Never seen or heard of one of these alleged mono portable devices…AM radio is mono, though.

    It’s just easier to hear phase issues in mono. That’s all the reason anyone should need IMO.

    • Tomislav Zlatic


      Oops – there was a typo in the article. I meant to say mobile phones, not headphones. :/

      Either way, it’s definitely easier to hear phase issues in mono, but it’s also important to keep your mix mono compatible because there are loads of mono playback systems out there.

  2. This is a great effect! Looks like I’ll need to go back into 500+ old projects and replace all the chorus, flanger, and stereo shaping plugs with which I attempted to widen the signal with this Apex one as it simply sounds much better :)


    • Tomislav Zlatic


      Oh yes, it’s quite subtle, but at the same time rich and full sounding. Really a great effect!

      Wouldn’t it be better to focus on finishing your current projects, though? :)

    • yes it is, just place the amount you want to pay for it…if you want it for free, just put 0 and click add to cart

      • No longer free, a minimum “donation” of $10 is required to access the download. If you type in zero, it goes into your cart at $10.

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