iBird Plus 6.1 for iOS devices on sale

To: David Adams <>
Subject: iBird Plus 6.1 for iOS devices on sale
From: Peter Shute <>
Date: Sat, 9 Feb 2013 07:37:46 +1100
I downloaded the lite version for a look at the spectrograms, and I think 
they're useful, but are limited by poor presentation. It's exciting that 
they're included, but they need work. I hope our local apps, Morcombe/Stewart 
and the forthcoming Pizzey and Knight/? include these sooner rather than later.

They seem to have applied some kind of noise suppression or compression to the 
recordings before generating the spectrograms, which results in areas of 
complete black between notes. But the background "noise" is present during the 
notes, so you get these confusing vertical blue bars, which should be ignored. 
You need to concentrate on the green bits only.

I'm thinking they've quantised the values into just high, medium and low 
(green, blue, black), rather than display a continuous range. This makes the 
loudest bits stand out, but hides the softer detail. I think it would have been 
better to just use a full greyscale.

Every track's spectrogram fills the width of the screen, so the time scales 
aren't consistent, and there are no times shown, just four pointless, 
identically placed tick marks on the time axis.

The frequency scale seems to be identical for each call, which allows 
comparison, but hides the detail of the lower pitched calls. There are no 
frequency labels, it just says "kHz". They could have made them much taller - 
they're so squashed that they lose a lot of detail. I think this alone would 
make a huge difference to their usefulness.

I find a well presented spectrogram to be invaluable for understanding a call 
well. These are better than nothing, but could be much better.

I wasn't able to find a way to start and stop the tracks playing, so I had to 
resort to turning the volume right down while I looked at several spectrograms. 
They just start playing as soon as you go into that section, whether you want 
it or not.

The spectrogram settings are just three quality/speed settings. These don't 
seem to affect the speed of spectrogram calculation on my recent iPad model, 
but might on an older one. They make the spectrograms look different, but I'm 
not sure what they do. If they affect speed of calculation they might control 
FFT window size or overlap.

It's interesting that they've included these controls. It means that the 
spectrograms are generated at the time of playing. This means that they could 
potentially give you control of more parameters like the quantisation and 
scales. I would have thought they would have carefully generated them 
themselves and stored them as images. I suspect someone has decided at a late 
stage to include spectrograms, and has just set it up to auto generate them all 
with the same parameters. If you could control more parameters, and could save 
them for each track, this would be a great leap forward in the presentation of 
bird recordings in apps, in my opinion.

There's a good tutorial on reading spectrograms at The Canyon Wren spectrograms at can be compared to those 
in the lite version of the app to get an idea of how much more useful they are 
when done well.

Peter Shute

Sent from my iPad

On 08/02/2013, at 3:46 PM, "David Adams" 
<<>> wrote:

 iBird, by
the way, also includes spectrograms for the bird calls. I'll admit I
haven't read up on how to make use of these, but they sure look great. As I
understand it, there's a technique for using to better memorize and recall
bird calls. Even without knowing what exactly they're all about, they're
interesting and you can easily "see" the call. Many of the on-line
recording libraries seem to be heading in the direction of including such
graphs with recordings.

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