Freesound Forums

Hi.

I'm using an FN-BC04 MP3 player board (also compatible with .wav files) to play one of four recorded growling sounds for a Halloween prop. The board's manufacturer recommends files with 8 or 16 bit resolution sampled at 44.1 KHz. I'm using WavePad to accomplish this.

Two of the four files play back just fine, but the two others exhibit an annoying "pop" sound at the very end of playback on the BC04 (I've tried two new units). I neither hear nor see this pop when examining the files in WavePad.

The BC04's manufacturer recommended saving the files in 12-bit format, but as far as I can tell WavePad doesn't support this.

I notice that the two files which don't pop were originally recorded with 32-bit resolution whereas the to files which "pop" were originally recorded in 24-bit resolution.

Any help fixing this problem would be appreciated.

Thanks!

"pop" sound at the very end of playback is usually caused by a non-zero-point ending sample.

To make sure that WavePad isn't hiding the problem (e.g. some programs apply micro-fades at playback start and end) do a paste-repeat of your converted sample on a track, play it, and pay attention at the seams.

If the converted sample loop sounds fine, then the board may be processing it internally (e.g. resampling)

Anyway, from this FAQ here:
https://www.electronics123.com/page/faq-fn-bc04

Q11: The .wav file has an audible "click" when finished playing on the module. However, there is no "click" when I listen to the file on my computer.

A11: We converted the frequency of the files from 22.05KHz to 44.1kHz and the "click" disappeared. The "click" also disappeared when we converted the files from .wav to .mp3 format.

Thanks for your information and suggestions, copyc4t.

It's interesting to learn that the most probable cause is a non-zero final sample.

I did try a fade and trim at the end using WavePad, but the FN-BC04 still exhibited a "pop" at the end.

Ultimately I found two other alternative sound files that don't exhibit the pop at the end of FN-BC04 playback.

Thanks again for your help!

Don't know if this is relevant but cured a similar problem for me once or twice.

A "pop" suggests a DC offset on the sample, where the positive and negative mean levels don't cancel out. Non-zero start or finish points produce a "click" because of the sharp rapid transition.

The old version of Audacity I use doesn't have a dedicated "DC offset correction" add-on so I used a High Pass filter set at 15Hz (could set as low as 2 to 5Hz?) to remove the DC. Worked perfectly without affecting the sound quality.

Wibby.

A bit late to the party here, but...

After years of end-of-sample pop and click misery, I now use some or all of the following steps when prepping samples (in Audacity) to prevent it from happening...

1. Use Select / At Zero Crossings to find the *true* zero crossing point (which is often a short distance away from the apparent zero point shown on the monitor) and cut the sample there.

2. Select the last, tiny (<0.1 sec) fraction of the sample and apply a fade out to it, so that I *know* for sure the sample is ending at zero (longer samples may justify longer fade times).

3. Use Generate / Silence... to add 0.05 - 0.1 seconds of nothing to the end of the sample, especially if the sound has a short decay time.

4. If your sample is very short (again, <0.1 sec), then use Generate / Silence... to make it at least 0.15 if not 0.2 seconds long.

Regarding 3 & 4: I don't know exactly why, but *some* computers / sound cards (like mine) don't seem to like very short sounds (like dry-sounding, closed hi-hats) and don't play them completely all the way through, thus ending them with a click. It's almost as though the machine stops playing the sample as soon as it's finished reading it, even if there's a little bit left in the buffer. I suspect it does the same on longer samples, but the effect is less noticeable.

That's why pretty all my drum sounds are at least 0.2 secs long, even if the sound itself only lasts 0.04 secs. Some may call it overkill, but it works for me. Once upon a time I might have worried about wasting memory or overloading processors with too many overlapping samples, but those aren't really issues any more.

You mention the "true" zero crossing point - why would the one shown on the screen in audacity be any different from the true one?

Another thing to note is that if the sound is in a lossy-compressed format (like mp3) then even if the original waveform ended properly with no offset, the compressed format might not due to the compression artifacts and processing blocks. And that's a good enough reason to add a bit of silence at the end. And my own computer is connected to a home theater system via HDMI, and whenever no sound is being sent, the audio processing turns off, and it takes it a very short time to start working again whenever the audio starts up again, making an argument for having a bit of silence at the start also (but I just consider that a bug of my own setup, and never bother adding silence at the start of any of my uploaded sounds -- YMMV).

You gotta fade it out properly or a few times. Also try cutting off a 'millisec' off the end and fading that out. || Unless it is a DC issue in which case sometimes a high pass filter can do the trick 😵‍💫 😏