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Show HN: I've built a spectrogram analyzer web app

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Re: Show HN: I've built a spectrogram analyzer web app

#41

Post by shangers »

lokimedes wrote: post #36
ssgh wrote: post #2

Author here. This is a basic spectrogram visualizer that's mobile friendly. It allows to select regions on the spectrogram and play them separately. There is no grand plan behind this web app: it's just a handy basic tool to capture sounds on your phone and see what they look like.

Hi, I love it. Perhaps we should chat about making it for radio data as well? We could potentially use it for our radar systems.

Can I ask what kind of use cases would a spectrogram have for radar data? I've been messing around with making my own spectrogram app as well (linux desktop app and not web app though) and would be stoked to know if there's any potentially easy to reach use cases for it

Re: Show HN: I've built a spectrogram analyzer web app

#42

Post by galcerte »

shangers wrote: post #41
lokimedes wrote: post #36

Earlier quoted context omitted.

Hi, I love it. Perhaps we should chat about making it for radio data as well? We could potentially use it for our radar systems.

Can I ask what kind of use cases would a spectrogram have for radar data? I've been messing around with making my own spectrogram app as well (linux desktop app and not web app though) and would be stoked to know if there's any potentially easy to reach use cases for it

Radar signals are modulated in very specific ways, which are visible right away even with plenty of noise on a spectrogram. Classifying the modulation of radar signals is something common in military contexts, since it allows you to listen for emissions and be able to tell if it's an enemy or an ally. I bet it has more uses than that, but it's the first one I could think of.

Re: Show HN: I've built a spectrogram analyzer web app

#43

Post by jo-m »

jboy55 wrote: post #25

Here is a spectrogram of the track, "Look" from the album, "Songs about my Cats" by Venetian Snares. https://imgur.com/sRe6Ypv Aphex twin did something similar, but this is more playful in my opinion.

I once (badly) did something similar as a student [1].

Unfortunately it's in Matlab so I can not run it any more.

[1] https://jo-m.ch/posts/2015/01/hack-the-spectrum-hide-images-...

Re: Show HN: I've built a spectrogram analyzer web app

#44

Post by quickthrower2 »

jboy55 wrote: post #25

Here is a spectrogram of the track, "Look" from the album, "Songs about my Cats" by Venetian Snares. https://imgur.com/sRe6Ypv Aphex twin did something similar, but this is more playful in my opinion.

https://venetiansnares.bandcamp.com/track/look

Warning - this music freaked my dog out!

Re: Show HN: I've built a spectrogram analyzer web app

#46

Post by scotteric »

jo-m wrote: post #43
jboy55 wrote: post #25

Here is a spectrogram of the track, "Look" from the album, "Songs about my Cats" by Venetian Snares. https://imgur.com/sRe6Ypv Aphex twin did something similar, but this is more playful in my opinion.

I once (badly) did something similar as a student [1]. Unfortunately it's in Matlab so I can not run it any more. [1] https://jo-m.ch/posts/2015/01/hack-the-spectrum-hide-images-...

You know a personal license is only $149 USD right? You could then run your old code. Toolkits for home are $49.

Re: Show HN: I've built a spectrogram analyzer web app

#48

Post by sorenjan »

jo-m wrote: post #43
jboy55 wrote: post #25

Here is a spectrogram of the track, "Look" from the album, "Songs about my Cats" by Venetian Snares. https://imgur.com/sRe6Ypv Aphex twin did something similar, but this is more playful in my opinion.

I once (badly) did something similar as a student [1]. Unfortunately it's in Matlab so I can not run it any more. [1] https://jo-m.ch/posts/2015/01/hack-the-spectrum-hide-images-...

If you want to run it again you could try Octave, an open source Matlab alternative.

https://octave.org/

Re: Show HN: I've built a spectrogram analyzer web app

#49

Post by 0xFEE1DEAD »

peepwaah wrote: post #13
djsamseng wrote: post #12

Earlier quoted context omitted.

This is a pretty good introductory primer. https://medium.com/analytics-vidhya/understanding-the-mel-sp... 1. STFT (get frequencies from the audio signal) 2. Log scale/ decibel scale (since we hear on the log scale) 3. Optionally convert to the Mel scale (filters to how humans hear) Happy to answer any questions

Thanks for your effort in sharing the link- am kind of comfortable with most of the theoretical aspects of STFT/FFT/MelScale etc.. but when i look at the spectrogram i still feel am missing something. When i look at the spectrogram i want to know how clear is the quality of the speech in the audio - is there background noise - Is there a reverb - Is there a loss anywhere - I have a feeling that these are possible to…

Look for clear and distinct frequency bands corresponding to the vocal range of human speech (generally around 100 Hz to 8 kHz). If the frequency bands are well defined and distinct then the speech is likely clear and intelligible. If the frequency bands are blurred or fuzzy then the speech may be muffled or distorted.

Note that speech like any audio source consists of multiple frequencies, a fundamental frequency and its harmonics.

Background noise can be identified as distinct frequency bands that are not part of the vocal range of human speech. E.g. if you see lots of bright lines below or above the human vocal range then there's lots of background noise. Especially lower frequencies can have a big impact on the perceived clarity of a recording whereas high frequencies come of as being more annoying.

Noise within the frequency range of human speech is harder to spot and you should always use your ears to decide whether it's noise or not.

You can also use a spectrogram to check for plosives (e.g. "s" "k" "t" sounds) as they also can make a recording sound bad/harsh.

Re: Show HN: I've built a spectrogram analyzer web app

#50

Post by michaelmior »

scotteric wrote: post #46
jo-m wrote: post #43

Earlier quoted context omitted.

I once (badly) did something similar as a student [1]. Unfortunately it's in Matlab so I can not run it any more. [1] https://jo-m.ch/posts/2015/01/hack-the-spectrum-hide-images-...

You know a personal license is only $149 USD right? You could then run your old code. Toolkits for home are $49.

$149 is still a significant amount for many people. Especially for something non-essential.
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