My favorite spectrogram phone apps

My favorite spectrogram phone apps

One question I get over and over again is: which apps work best if you want to make spectrograms on your phone? I’ve got a couple of recommendations. (Note: I have no financial interest in any spectrogram app.)

Why use a spectrogram app?

Spectrogram apps are terrific because they can allow you to make a picture of a sound right when you hear it. If you are trying to identify bird sounds, a spectrogram app can show you the shape of the sound, and then you can compare that shape to the ones in the Peterson Field Guide to Bird Sounds to find a match. It turns bird sound identification into a visual challenge, which can be really advantageous since many of us have an easier time remembering visuals than sounds.

What should I look for in a spectrogram app?

There are a lot of apps out there that will generate spectrograms. If you are interested in bird sounds, here are the main features to look for:

  • The top of your display should be around 10,000 Hz (= 10 kHz). This is roughly the average upper limit of hearing in many adult humans, and it’s roughly the upper limit of most bird sounds too. If your app doesn’t top out around 10,000 Hz, look for the option to change “sample rate” or “sample frequency.” The top frequency on the display will be half the sample rate. Thus, a sample rate of 22,000 or 24,000 Hz should generate a display that is around the optimum height for bird sounds.
  • The display should scroll across about an inch of screen per second. Most apps don’t scroll this fast, so just look for one that has the fastest possible speed. If the scroll moves too slowly, the bird sounds will end up looking horizontally squished, and it will be hard to see the necessary detail.
  • The display should have a black-on-white option. The default is usually multicolor-on-black, which is not ideal. Grayscale-on-white is much easier to read, because the sound is the signal; it is the text. Text should always be dark-on-white for extended reading.
  • The display should scroll, not wrap. That is, the whole spectrogram should move across your screen from right to left, with the most recent sounds at the right.
  • You should be able to pause and screenshot the display. This allows you to “take pictures” and save them for later viewing.
  • You should be able to play back the recorded sound later. Even the worst-quality phone recordings are usually higher in resolution than phone spectrograms, so recording the sound is highly recommended.

So… which apps do I recommend, as of February 2019?

For iPhone: SpectrumView

SpectrumView for iPhone is great because it has all the above features in the free version. I don’t own an iPhone so I haven’t used it myself, but it’s highly rated and from what I can tell, does a very nice job of illustrating bird sounds.

For Android: SpectralPro Analyzer

On my Android phone, I use SpectralPro Analyzer by RadonSoft. It’s not as good as SpectrumView, but it’s the best I’ve been able to find for Android. The two big drawbacks are: 1) that it does not record audio; and 2) that key features are only available in the paid version. Last I checked the paid version was only about $5. And to work around the lack of recording ability, you can  always download a separate free audio recording app and run it at the same time as SpectralPro. That’s a little clunky, but it does the job.

If you are aware of any app that can do better than the ones I’ve listed, let me know!

6 thoughts on “My favorite spectrogram phone apps

  1. I’ve downloaded the app and wonder which in app purchase would allow me import an audio file for analysis. I use an iPhone so I use Voice Memos or Zoom Handy Record to record my bird songs.
    Thanks

  2. Hi Lisa. That’s a good question. I was focused only on the ability to create a real-time scrolling spectrogram of the audio from the microphone, so I didn’t check for the ability to make a spectrogram from a pre-existing audio file. On my laptop I use Raven for that. You can download the free version, Raven Lite, from ravensoundsoftware.com. Not sure what the system requirements are, since that link seems to be dead on their website. And I’m not sure if there is a comparable package that will work on a phone. Maybe somebody reading this will know more than I do.

  3. Thanks for this useful post, Nathan – I’ve long wanted to experiment with spectograms on my iPhone, so following your advice just downloaded SpectrumView for iPhone. However, the vertical frequency axis tops out at 8000 Hz, not 10000 Hz as mentioned in your post. I’m only using the free version, but the in-app purchase options don’t appear to offer the facility to change this (nor would I expect them to).
    Regarding Lisa’s question about importing audio files, it seems this can only be done from the user’s iTunes Library or SoundCloud Library. These options can be accessed via the Playback function, but require an in-app purchase (albeit an inexpensive one).

  4. Thanks for the info, Dominic! A vertical axis to 8000 Hz will still catch most bird sounds except for the very highest ones. Good to know there is an option for importing audio files, even if the methods are limited.

  5. Hi Nathan. I have used a few audio apps to make recordings. I suggest you look at Tom Stephenson and Scott Whittle’s BirdGenie (http://www.birdgenie.com). So far it has been the best app to quickly record a song. As soon as you start the app it starts pre-recording. You can tap virtually anywhere on the screen to start recording. The pre-recording is to ensure you get the beginning of the call even if you are slow to start recording. The main purpose of the app is to ID the bird calls but so far it’s pretty limited in which species it recognizes. After you make a recording you can see the spectrogram.

    The other bird ID app that makes recordings is David Sibley’s Song Sleuth. It also pre-records. It’s a little slower to start up and you have to tap a little circle to start recording but it has a live spectrogram.

    The last app I have tried was recommended by Cornell Lab. It’s called Voice Record (free). The best thing about this app is it allows you to record at the eBird recommended sample rate of 48KHz and a bit depth of 24 bits. All three can record .WAV files which is also the recommended format for eBird. This link is very helpful: https://help.ebird.org/customer/portal/articles/2159648. I follow their suggestion to normalize the bird sounds, using Audacity. It’s a simple method that makes the sound files sound so much better!

    Each of the three is a bit lacking. If only they could combine their powers to make a perfect bird recording app that you can tap anywhere to start recording, pre-records, records in 24-bit WAV, and shows a live spectrogram. It would also be nice you you could directly upload it to your eBird checklist through the app. One can dream…

    In response to Dominic, SpectrumView does have the ability to display 10,000 Hz. You need to go into settings and change the Audio Sample Rate to 24,000 then you can change the Maximum Frequency to 10,000.

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