Subject:Best quality 8-11 WAV files

Posted by: gigasaurus

Date:12/9/2006 12:05:58 PM

I am doing some work for a toy company that requires wav files that are downsampled to 8-11. I delivered the first batch of sounds and i used SoundForge batch converter's "save as" function and saved a copy of all the files as 8-11. That worked, but the client is asking if I can achieve higher quality. Are there any tricks anyone knows on how to get the best quality when downsampling WAV files? These particular sounds are animal growls and chirps.

Subject:RE: Best quality 8-11 WAV files

Reply by: Chienworks

Date:12/9/2006 3:33:13 PM

Noises lose quality faster than other sounds, so you're in a tough spot. Try resampling within Sound Forge first. You can then apply the antialiasing filter while resampling. This can do an amazing job of preserving quality. Then save as a separate step.

8 bits has much less dynamic range than 16 bits. Make sure your recordings are all normalized to near maximum levels while still in 16 bits. If you recordings are quiet then converting to 8 bits will be very damaging.

Subject:RE: Best quality 8-11 WAV files

Reply by: Skaven252

Date:12/11/2006 12:44:12 AM

I second the dynamics part. You could even consider compressing the samples quite heavily using a tool like the L1 Ultramaximizer to get as much volume out of the little dynamics you have available, this should improve the signal-to-noise ratio. The Ultramaximizer also does 8-bit quantization and noise shaping that may be helpful.

Downsampling to 11050Hz may get some nasty Nyquist artefacts into the sounds, so like Chienworks says, use anti-aliasing. You could also try filtering the high frequencies out more aggressively with a Paragraphic EQ or a low pass filter before resampling.

Subject:RE: Best quality 8-11 WAV files

Reply by: Skaven252

Date:12/11/2006 12:47:14 AM

Oh, and since you mentioned toys... the sounds are going to be played through a small tinny toy speaker, right? Try to get the frequency response specs of the speaker, you may have to do pretty heavy EQing to the samples to get maximum loudness and quality out of the speaker.

Basically, if the speaker is small it doesn't play low frequencies, so you should filter them out of the sample as they hog dynamics away from the playable frequencies.