LFE track for decoded SQ recordings with Adobe Audition

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podman

New member
Joined
May 6, 2007
Messages
5
Hi

I'm a newbie here, so please be kind to me!

I've successfully used the AA2 script posted on this forum to decode some SQ recordings into 4 wav files, which I've encoded into DTS using SurCode CD Pro DTS.

When playing them back, the four channels have been decoded correctly, but they sound very thin, lacking in bass. I have some DTS discs that Tab made me a few years ago, which utilise the LFE channel and sound good on my system.

My question is, how do I go about making an LFE track from my four wav files in AA2? Any tips would be appreciated.

Many thanks
podman
 
Of course, I am quite new here myself!
Basicall I would like to point you - and everyone else - to this article http://www.ambisonic.net/bassmgt1.html and this part 2 of it http://www.ambisonic.net/bassmgt2.html.

Basically,the point is that for music one should not put music into the LFE channel. The LFE channel is not the sub-woofer, even if some treat it that way. The LFE should be used for dinosaur footfalls and astroids smashing into Earth.

The subwoofer output from the AV receiver (AVR) should be a mix of the LFE and the bass in the five other channels. But if the five (LF,RF,CF, LB, RB) speakers are full range, all bass should go to all these five. Including the LFE.
So the AVR bass manager should take care of this for you. In other words, but the four channels from the SQ disk into LF, RF, LB and RB, and nothing into LFE. And in my opinion nothing into CF either.

LF = Left Front
CF = Center Front
RF = Right Front
LB = Left Back
RB = Right Back

Another thing to note is that the old quad systems placed the four speakers in the four corners of the room, while todays surround systems' rear speakers are more side speakers. However, the rear two extra speakers of 7.1 systems are locaed quite the same as the old quad systems did.

Best regds
Rolv-Karsten


Hi

I'm a newbie here, so please be kind to me!

I've successfully used the AA2 script posted on this forum to decode some SQ recordings into 4 wav files, which I've encoded into DTS using SurCode CD Pro DTS.

When playing them back, the four channels have been decoded correctly, but they sound very thin, lacking in bass. I have some DTS discs that Tab made me a few years ago, which utilise the LFE channel and sound good on my system.

My question is, how do I go about making an LFE track from my four wav files in AA2? Any tips would be appreciated.

Many thanks
podman
 
My question is, how do I go about making an LFE track from my four wav files in AA2? Any tips would be appreciated.Many thanks
podman

Welcome, podman.

You can use a sub-harmonic synthesizer, made by dbx (right?) decades ago.

Maybe AA has an option for doing the subharmonic synth in software.
 
Hello Podman. This subject has come up before and you might want to read this thread:
https://www.quadraphonicquad.com/forums/showthread.php?t=7232

Basically - if I'm not mistaken - you want to have full range sound in your main speakers and in general forget about the LFE, because it's real tricky to do right and there are "Bass Management" issues on one's receiver that can come into play. Besides, there was no LFE in the 1970's for Quad systems. There are experts on the board who can give you a more detailed answer on this subject if you need more info.

I agree with rolvkarsten, keep 1970's Quadraphonic pure - do not put anything in the CF channel for preservation sake. 4.0 mixes and 5.1 mixes are similar but separate animals that provide different "air" and feel in the room IMHO.

I have not used the script for AA 2.0 yet, but there are actually 3 different variations for the script, Low, Mid and high, if I correctly understand the notes for the script(s). That may account for the thin sound or maybe your using small satellite speakers that give the sound. Try full rage speakers on your system if you are not already doing so. Hope this is helpful.
 
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Thanks for the replies so far - there are some interesting points there.

I have not used the script for AA 2.0 yet, but there are actually 3 different variations for the script, Low, Mid and high, if I correctly understand the notes for the script(s).

Where can I get these three scripts? What does Low, Mid and High relate to?

My surround system does have small speakers, but the bass management in the Amp normally makes everything sound Ok, perhaps I need to ask Tab how he used to do his DTS CDs. I guess he's on this board? Does anybody know his user name, so that I can PM him?

Regards
podman
 
I make a mistake about the script info, this refers to QS decoding with AA 2.0.
From the QS notes:

Note: There are three versions of the same script.
The difference is how strong the common information is x-talk cancelled:
- QS_01_low (might be too weak)
- QS_02_med (a good starting point)
- QS_03_high (might also work well)

I'm not sure if Tab is active on the board anymore you might want to contact him directly. But, someone here with more knowledge than myself should be able to provide you with help here.

Have you tried converting other titles? Perhaps something went wrong converting your source material. It should work according to those who use it all the time. I've used Surcode DTS after converting with AA 1.5 with great results - full range sound and no LFE. Also, recheck your volume levels before exporting into separate mono wav's.
 
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I've used Surcode DTS after converting with AA 1.5 with great results - full range sound and no LFE. Also, recheck your volume levels before exporting into separate mono wav's.

I've been experimenting and have discovered something peculiar. My normal audio editor is WaveLab (WL) - I'm only using AA to try this SQ decoding trick. WL handles surround files, so I did an experiment. I used the Montage to render Lf,Rf,Ls,Rs WAVs from the front.wav and rear.wav files, which works a bit like Export the AA Multichannel Encoder.

Doing an A/B test with DTS files of the AA output vs. the WL output, the WL output had much better bass response... how strange?! Perhaps there's some phase issues that AA introduces?

I did make an LFE track in Wavelab, but I have to agree, it sounds better without it!

So from now on, I'll do the decoding in AA and the export in WL.

podman
 
Doing an A/B test with DTS files of the AA output vs. the WL output, the WL output had much better bass response... how strange?! Perhaps there's some phase issues that AA introduces?

That's an interesting discovery. One that should be looked into further to find what's going on. Glad everything is working out otherwise.

So far I've had nothing but problems with AA 2.0, it won't recognize my card as multi channel, only stereo. With AA 1.5 I did not have this problem. Perhaps it's because both are trial versions. As a result, I'm not able to export the wav's that we're done in AA 1.5., perhaps this topic belongs in another thread.
 
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After making the four .wav files, can't you burn them to DVD-Audio files? I understood DTS to be a compressed format. Maybe I've got that wrong?
 
After making the four .wav files, can't you burn them to DVD-Audio files? I understood DTS to be a compressed format. Maybe I've got that wrong?

Yes, I could make a DVD-Audio disc, but while I am getting to grips with AA and the SQ script, I have chosen this method. If I get good, then I will learn how to make DVD-Audio discs with WL.

podman
 
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