Need a tool to cutoff frequencies outside auible range in a WAV file

[DJ Alik]

Hi. I am looking for a tool that would let me see the cutoff frequency that was used during encoding of that file.

[DJ Bobo]

Use RazorLame. It's a GUI for Lame. There you can adjust the lowpass frequency. That's if you're encoding.

If you're just curious about an MP3 file, open it in CoolEdit and activate Frequency Analysis while playing.

[DJ Alik]

i am using Sound Forge 6. and it gives me a very nice spectrum graph but i was wondering if there is something that would tell me EXACT cutoff that was used in the encoding of a particular mp3.

The reason i am doing this is because I reencode most of the mp3 files that I download after "cleaning" up the sound (noise gates, normalization, silence removal etc) and i don't want to overkill the bitrate by using a higher frequency cutoff than the one used in the "original" encoding.

[DJ Bobo]

You don't need *very* precise information. You look where the graph falls dramatically, you note that frequency, add 1 KHz, that's it. Even when you add 5KHz, it won't affect anything, because the MP3 encoder discards automatically what goes beyond the original lowpass frequency (it kinda detects it on its own)

[DJ Alik]

I've been playing with different mp3 files all day today and still can't figure out how to use the Sound Forges spectrum analyzer. If I select the file and just run spectrum analyzer does it gives me a graph but it shows that the frequncy is cutoff around 16khz. But if play the same file while having the spectrum analyzer on I see that there are some samples that jump all the way to 20khz. Is there a way to see what's the maximum frequncy of a file? Basically i am trying to compare original wave and the encoded mp3 and see how much they differ.

[DJ Alik]

still no replys :confused: well can someone maybe just teach me how the spectrum analyzer works and what i need to look for?