Quote:
Originally posted by soundhound:
I could indeed check that, but I'm not quite certain what you want me to check for. Please 'splain.


The behavior in question involves the triple crossover settings and their effect on the low pass to the sub output of the Main, Center, and Surround signals. The LFE signal and how it is handled and what output it shows up at is not the issue at the moment.

If the Mains are set to Small and high-passed at 40Hz, and the Surrounds (or Center) are set to Small and high-passed at 150Hz, the Sub output should have the Main information low-passed at 40Hz and the Surround information low-passed at 150Hz. The concern I see being raised is that the Sub output might be low-passed at 40Hz, the lowest of the settings, thus leaving a "hole" between 40Hz and 150Hz where the Surround info is not sent to an output.

Here's the setup I'd use to test this if I had a 950...

Source:
Full bandwidth pink noise, from 20Hz - 20kHz, fed into the CD input.

Measurement:
Spectrum analyzer to check what's coming out of the Left, Surround, and Sub outputs of the 950. Note no amp/speaker/room effects, we want to look at what the processor is doing.

950 Settings:
The 5-STEREO processing mode on the CD input. All channel output trims to 0.

Check One:
Set Mains, Surrounds, and Center to Large.

Verify that the 5-STEREO mode sends the full bandwidth pink noise to Main, Surround, and Center outputs, and nothing to the Sub output. If it doesn't, stop here, and wait for soundhound's DD disc.

Check 2:
Mains Small, high pass at 40 Hz.
Surrounds and Center Large, so nothing from them should go to the Sub output.
Sub On.

The Main output should roll off below 40Hz, and the Sub output should roll off above 40Hz. Do this to note what the Sub's low-pass rolloff looks like on the analyzer. Surround and Center output should still be full range.

Check 3:
Mains Small, high pass at 40Hz.
Surrounds Small, high pass at 150Hz.
Center Large, so nothing from it should go to the Sub output.
Sub On.

Again, the Main output should be rolled off below 40Hz, but now the Surround output should be rolled off below 150Hz.
The Sub output should have Main AND Surround up to 40Hz, so the Sub output level below 40Hz should be 6dB (or 3dB?) higher than Check 2. The Main contribution should start rolling off above 40 Hz, but since the Surround info should be present from 40Hz to 150Hz, the sub output should not fall off like Check 2, but flatten out a bit between 40Hz and 150Hz. Then the Surround contribution should start rolling off above 150Hz. If you change the Surround crossover frequency, the sub output above 40 Hz should change also. If you change the surround trim to +10, then it should dominate the sub output, and make the effects easier to see.

If the 950's internal calibration signals are full-bandwidth pink noise and "upstream" of the crossovers, you could use them instead of the CD/5-STEREO input, and be able to check the sub output for Main or Surround or Center separately. If the LFE calibration is full range, or at least 20Hz to 200Hz, you could do something similar to check the effect of the triple crossover on the LFE roll off in the sub output, if there is one.

Quote:

Note: I am one of those crazies that does not use the bass management feature: I have full range speakers all around, but I have an analog 60Hz crossover network inline with my front left and right feeds. I set the 950 to 'no subwoofer', which feeds the LFE to the front left and right mains. It is split to the subwoofers (4, in stereo) by the external crossover. I do set the center crossover for 150Hz, but I do this because it kind of 'spreads' the dialog across the front, taking the point source onus off the one center speaker.

Anyway, what I'm trying to say in a longwinded way, is that I might not be able to do the measurement you are asking for since my system does not use the LFE in the traditional way. Let me know.....


If I upgrade (from my current ProLogic!!!! setup) my Main output would be set up like yours, Large with an external crossover to my one lowly sub and front speakers, with the 950 Sub output off. My Center and Surround outputs would still be Small, so info from them below their crossover points (and ALL the LFE info, too) should end up at the Main outputs, where they would be divided between the sub and mains.

Hope this helps, and is coherent!


[This message has been edited by bergermeister (edited November 08, 2002).]