Equalize Your Listening With HiFiScan

Audiophiles will go to such extents to optimize the quality of their audio chain that they sometimes defy parody. But even though the law of diminishing returns eventually becomes a factor there is something in maintaining a good set of equipment. But what if your audio gear is a little flawed, can you fix it electronically? Enter HiFiScan, a piece of Python software to analyse audio performance by emitting a range of frequencies and measuring the result with a microphone.

This is hardly a new technique, and it’s one which PA engineers have used for a long time to tune out feedback resonances, but an easy tool bringing it to the domestic arena is well worth a look. HiFiScan is a measuring tool so it won’t magically correct any imperfections in your system, however it can export data in a format suitable for digital effects packages.

Naturally its utility is dependent on the quality of the hardware it’s used with, but the decent quality USB microphone used in the examples seems to give good enough results. We see it used in a variety of situations, of which perhaps the most surprising is a set of headphones that have completely different characteristics via Bluetooth as when wired.

If audio engineering interests you, remember we have an ongoing series: Know Audio.

28 thoughts on “Equalize Your Listening With HiFiScan

      1. For a venue you’d need a system capable of optimizing individual long FIR filters for a ton of speakers and a ton of listening positions. Bela could do the zero latency convolution with open source, but the open source software to create the filters doesn’t exist.

        For closed source there is AFMG FIR maker.

        1. “For a venue you’d need a system capable of optimizing individual long FIR filters…”

          Kids these days. Back in my day, you’d hang some blankets on the walls, maybe point the speakers more this way or that way, and call it good. These days you need a DSP PhD just to tweak your tweeter.

          I’m kidding. My experience is that show sound increases with technological sophistication of the engineers. I remember when 9:30 in DC pulled all its audio cable and replaced it with ethernet direct to speaker/amp combos. Saw two shows shortly after that really blew my mind.

          But I’m also not kidding — you can do a lot with simpler means as well. Punk rock style.

          1. Especially as long as you don’t care song text is unintelligible for most of the audience. This is the reality with traditional setups, sound from a dozen speakers can’t add up to something intelligible with only simple delay and volume.

            Sound engineers seem a bit resistant against FIR though. For fixed venues they are willing to use AFMG’s various software, but for on the fly they want knobs, not measurement and calibration.

      2. For a few decades now, sound systems are often quickly checked and EQ and levels tweaked by playing pink noise through the speaker(s) of interest, picking up the sound with an instrumentation mic at a representative location, and viewing the mic signal on a spectrum analyzer.

  1. Bluetooth sounding different is no surprise. I had a TV, well several, that looked completely different (better) through the VGA port. Maybe color space or some post processing due to the analog signal.

  2. We’re missing one final (important) part in the listening chain here. The person’s ears. I’m pretty sure with all the differences between people, hearing is different as well. So maybe that should be measured, and compensated for, as well?

    1. Compensated, but to what?

      Getting things right “by ear” is kinda like wine tasting. You get used to the sound in seconds and then keep twisting the knobs until you’re way off. Then you come back the next day and find it’s all wrong.

    2. There have been some efforts at that. Sony have this thing where they 3D scan your head to pick (or build) an appropriate HRTF for their headphone surround effect. Samsung have a simple wizard built into their phones that lets you tweak EQ through a series of audio tests. Years ago HTC put mics into their bundled earphones, the phone would play test sounds while you’re wearing the earphones and the response the mics picked up is used to correct audio output.

    3. Until there’s a SPDIF input at the base of your skull, your ears are the only sonic inputs you have. Whether you’re in the same room as a string quartet, or listening to a recording of them, you use the same ears. There’s no “right” ear response curve that your ears need to be “equalized” to. If the reproduction system (including the listening room) is capable of faithfully reproducing the sound of the thing that was recorded… job done.

  3. When I hear the term smart speaker they mean smart microphone and the network it’s on. The speaker is passive and dumb. These speakers and phones are smart. Bose did RTA in a home system years ago? My curb find surround amp has a mic jack for some EQ setting. Having four 10 band EQs I”ll pass.

    Phones-hearing aids will now do some of this for the user, more to come. Over the counter soon.

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