Jump to content
maxmercy

The Low Frequency Content Thread (films, games, music, etc)

Recommended Posts

I can't speak for anybody else but I rip the movies to my computer and then use SpecLab to directly read the digital audio file.  I had a lot of issues when I tried to run things through my sound card as well so I quit doing it.

Share this post


Link to post
Share on other sites

in the 'file' menu there's an entry for 'audio file and stream analysis'.  In that menu select 'analyze audio file (without DSP)'.  That'll take you to a menu where you can select the audio file and set the FFT lengths.

  • Like 1

Share this post


Link to post
Share on other sites

I can't seem to add the dts file, what program do you use to convert it into a wav file? Sorry I should of asked this from the beginning.

 

I use eac3to.  It'll convert Dolby and DTS files to multiple WAV files (one for each channel).  Then those files are mixed down to a mono WAV in Audacity.

  • Like 1

Share this post


Link to post
Share on other sites

That's interesting, i would of thought that down mixing especially to mono would pretty much ruin the audio file and not give an accurate result. why would it not do that?

A receiver does pretty much the same thing, redirects all (5 or 7 channels) the low frequencies to the lfe (mono).

  • Like 1

Share this post


Link to post
Share on other sites

That's interesting, i would of thought that down mixing especially to mono would pretty much ruin the audio file and not give an accurate result. why would it not do that?

 

Mixing WAV's together doesn't do anything to the quality of the audio (unless you change bit rates or sampling frequencies).  We have to do that mixing in order to create the PvA graphs and level numbers when we graph movies.  You can run individual channels through SpecLab if you want to see what's going on in them but in order to capture the overall bass in a track you need to mix them down to a single file.

Share this post


Link to post
Share on other sites

To the best of my knowledge SpecLab can't process multichannel WAVs, it can only do mono.  That's why we do the mixdowns

Share this post


Link to post
Share on other sites

 

the second one was done by extracting all channels then adding them to Audacity and exporting as mono wav in the same 24bit as the original movie files.

 

You have to respect the differing digital signal levels in the lfe channel vs the other channels. Just summing them doesn't deal with this.

Share this post


Link to post
Share on other sites

As a note of interest, mixing all the channels down to mono does potentially discard content, even though bass management does exactly the same.  If the bass is out of phase between one or more channels, then there will be some cancellation on the mix-down or after bass management.  OTOH, if you are running full-range mains (or a low XO like 40 Hz), that bass will still get played by the speakers.  The direct sound arrival for that bass may cancel at the listening position, but it will be returned to the listening position in later reflections.  This is an interesting dilemma because it means that amount of bass reproduced from a track depends to some extent on the mains XOs used.  The "reference" for bass managed systems is somewhat ambiguously defined.

Share this post


Link to post
Share on other sites

The direct sound arrival for that bass may cancel at the listening position, but it will be returned to the listening position in later reflections.

What do you mean by that exactly? The difference between the transient leading edge of a signal vs steady state or something else?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×