You may be too close to the work. I can listen to the ACX sample all day long without thinking there was anything wrong with it. How are you listening? Right this second, I’m on good, wide range, high quality Sennheiser headphones. If you’re listening on the built-in speakers of your laptop, I can see why you would think the work suddenly vanished. The resampled clip they offer is less crisp than your original.
I think your original has a little too much talking-into-a-wine-glass sound. That can be caused by excessive Noise Reduction and/or making a poor MP3. They usually catch that during the QC process, but yours is pretty subtle.
One personal preference, I think your submitted clip is too crisp and sharp, almost harsh. I think their version is easier on the ears, or at least on mine.
We know ACX resamples and recompresses the works for different products and services. They said so. This is where doing production in MP3 format just kills you. Each step in the production process causes the MP3 compression artifact damage and distortion to go up and you can’t stop it.
We recommend very strongly to do all your personal production in WAV (Microsoft) 16-bit—the Audacity default sound file format—and only stoop to making an MP3 just before you submit. I know some people think they need to do everything in MP3 because that’s what ACX requires.
There is a trick to submission.
be a 192kbps or higher MP3
192 is not a requirement, it’s the minimum. You can go higher than that.
You may upload 256kbps or 320kbps files if you’d like…
…and it’s recommended as long as you don’t go past the 120min chapter count or the file size limit…
Each uploaded file must be no larger than 170MB.
Those are all direct quotes from the ACX published specifications.
Submissions higher than minimum will help minimize distribution and product generation damage.