Home Theater Forum and Systems banner

1 - 4 of 4 Posts

·
Registered
Joined
·
47 Posts
Discussion Starter #1
I'm wondering if Bruce or someone could speculate what might be going on.

First this is not a standard room measurement I'm doing. There are no Mic, Speakers or Room Effects in these measurements. And no smoothing.

Most folks with Meridian systems love to listen to 2 channel music in a Music processing mode call Trifield. Which creates a center channel and some rear ambience. Generally works great.

Some folks that have much better main speakers than center speaker prefer to shut the center speaker off. There is a debate if this is a "valid" listening mode or not. So I thought I'd try to check it.

I always had thought Trifield left the mains alone and just added center and rears.

So I measured the left speaker (Preamp out directly connected to sound card) and compared it to straight stereo left channel.

The results are bizarre in that Trifield has this large rolloff starting at around 10Khz. But only SOMETIMES !!

Every few times I measure it, it's perfectly flat. When I measure straight stereo it's always flat.

But when I measure it with trifield it varies.

What could Trifield be possibly doing that would confuse REW? I tried changing the number of averages thinking Trifield might do some sort of time shift and it might not average correctly. But it was the same random results.

Would looking at impulse or something help diagnose what it's doing?

By ear it sounds fine.

Any ideas what might be going on is appreciated.

Same results using EMU USB 0404 and TASCAM US-144

I'm using the live loopback to calibrate.

 

·
Registered
Joined
·
7,514 Posts
Music processing mode call Trifield
You just answered your own question. REW is a mono signal. Processing modes and soundfields rely on phase for their signal direction. A mono signal does not qualify.

brucek
 

·
Registered
Joined
·
47 Posts
Discussion Starter #3
But even with a stereo signal can't some components be mono? Periodically you may hit a mono track on older music, would that mean it would roll it off?
 

·
Registered
Joined
·
7,514 Posts
Periodically you may hit a mono track on older music, would that mean it would roll it off?
I have no idea what their Trifield soundfield does.

You simply cannot use a soundfield algorithm with the REW mono signal. The results are unpredictable.

brucek
 
1 - 4 of 4 Posts
Top