There are some .wav files at documents\deflemask\samples

the format is like
\samples\hihat_1.wav

Format : Wave
Format settings : PcmWaveformat
File size : 14.8 KiB
Duration : 237 ms
Overall bit rate mode : Constant
Overall bit rate : 513 kb/s

Audio
Format : PCM
Format settings : Little / Signed
Codec ID : 1
Duration : 237 ms
Bit rate mode : Constant
Bit rate : 512 kb/s
Channel(s) : 1 channel
Sampling rate : 32.0 kHz <- here this could be less
Bit depth : 16 bits
Stream size : 14.8 KiB (100%)

they seem to be all mono. and 16bit.

Im resampling them in 16 bit mono and Deflemask just ignores them when selected. Doesnt even preview the file or give me an error message.

Okay i tested myself.

i can load the .wav file like this.

On Instrumentlist : double click orange "Samples"
click big orange box "+"
load custom sample.

now i have a custom sample loaded.
Its in the Sampleslist and i can preview the sample.

The only systems i could hear this custom sample in editor added as note "C" was in

NEO - GEO -> SP1 (chanel) other SP2-6 chanels might work too.
NES + FDS -> PCM works too
ARCADE -> SP1 other SPx chanels might work too.

Yup, I know that not all systems support sample use. I figured it out though thanks to a vid on Youtube from Inglebard Gaming. Using Audacity instead of Edison and resampling to 16000hz and exporting as an 8 bit unsigned PCM sample.

aha, i tested with some donwloaded. good to know

The WAV format has NOT stayed the same from the time in Windows 3.x (3.1, 3.11 etc) to now. It changed a lot, especially in the 90's, but since XP has *mostly* stayed the same. WAV format can be a few different formats, pcm is just one of them. There's even ones encoded and compressed similar to mp3 format from the Win98~XP era, some of which can't even play on a modern OS (I've run into this when perusing old disks). However, most of the modern OS's (all Windows since 3.x) will play the uncompressed variety just fine, including the sound effects off the old Windows 95 themes CD's I have here at the desk (well I guess that optical drive is good for something now, isn't it?).
So don't always assume that wav files are these simple formatting things, they can have a few different internal formats and can be picky to work with at times.
Still, it's easier than working with sound in the 90's, of which wav was one of several completely different formats, including VOC and some others. IIRC it was a blessing when Winamp came out around 98 or 99 and you could 'freely' play just about all the different formats with one piece of software.
When in doubt, set mixer settings (bass/treble/pan/EQ) level and record the audio from one software to another if your soundcard lets you do this, OR, convert the format using audacity or something similar to that (sometimes easier especially with motherboard audio which can be 'iffy' on a good day).
Be careful when using 8 bit samples, as they won't have nearly the precision of audio recreation that 16-bit samples would, and can sound really tinny or just plain terrible depending on what is playing it (software and hardware, and if it interpolates sound or not). It's not just samples per second in hz or khz you want to worry about, but I believe it's 8-bit that only had 256 different levels of sound available per sample (meaning, the level of the audio, like when you look at a spectrum analyzer). 16-bit has some 65,536 levels, I believe, or something crazy high like that. Though, that said, if you're making something decidedly old sounding, that 8-bit sample might be just the ticket.
All in all it shouldn't be too much of an issue either way here, once you figure out what format they are, and how to get them into this software.