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.



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).]

bergermeister:

Well, it's raining cats and dogs here in Los Angeles, and I don't have any work to do at the moment, so I'm breaking out the B&K calibrated microphone and RTA and will do some tests. I'll upload screen shots of my results.

The pink noise generator in the 950, like that in all consumer HT equipment is band limited to the region around 1Khz. This makes it pretty useless to test fequency response.....more to come.

Here is what I have figured from the manual and the other double bass thread (which I can't find right now). For all inputs but the 6 channel input, there are two speaker sizes, large and small. When speakers are set to small, everything below the crossover is sent to the sub. When speakers are set to large, no bass is redirected from them. They receive the full signal whether there is a sub or not. The sub will receive th ".1" and anything below the crossover from the small speakers. If there is no sub, all of this bass that would have gone to the sub will now go to the mains.

The 6 channel input works differently. This works independently of the other bass management! The crossover is set to 80 hz, it can not be changed, only turned on or off. When it is off, all speakers will receive the full signal whether they are marked large or small in the other bass management. When it is on, all signals below 80 hz will be sent to the subwoofer. This next statement is speculation, but if you do not have a subwoofer, I believe the signals below 80 hz will be dropped. The switch basically decides whether all speakers are to be treated large or all speakers are to be treated small.

Like Charlie said before, there is no double bass. If you have double bass, you really have some funky splits and connections in your wiring. If I missed anything, or misunderstood anything, please let me know.

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

bergermeister:

Looks like we'll have to stop at step #1...

First of all, if you set the front left and right mains to 'small', you are forced to have the subwoofer setting to "on" so I can't duplicate a 'normal' setup.

When I play pink noise in STEREO 7 in my current setup, there is very active cross-steering going on. When I play pink noise on a CD which is only on the left channel, it gets re-directed to ALL the other speakers, left _and_ right surrounds and back surrounds and center, to some extent.

Anyway, I did take a nice screen shot of the response of my front right main speaker

http://home.earthlink.net/~soundhound/response.jpg

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

Lena, Absolutely! When people think of matrix decoders, the sound of old Pro Logic usually comes to mind. Too bad. Not enough people realise just how good mordern matrix decoders (PL II, LOGIC7, Circle Surround II) can be. That's fine for spreading out the centre channel content of discrete 5.1 sources. But for listening to 2-channel material via PL II, there may be an easier way: use the Centre Width parameter on the PL II Music mode. Don't let the "Music" moniker prevent you from using that mode for movies. Instead, think of it as PL II with adjustments.

If you find a recording (TV, movie, music) too bunched up around the centre speaker, use the Centre Width control to spread centre channel content out towards the front Left & Right speakers. Keep in mind that you can fine tune the spread as you have eight (count 'em, 8) distinct steps from Min (ALL mono content steered to the centre channel) to Max (NO content steered to centre, i.e. Phantom mode).

On recordings that you think are too flat or boring, you can turn the Dimension parameter ON to give the sound a wrap-around effect. While that effect, obviously, is not appropriate for all recordings, it is surprisingly useful on some older soundtracks and some dryly-recorded music.

You can also adjust the balance you hear, between the fronts and the surrounds, by using the Soundstage control. It works kinda like real life: i.e., as you approach the front of a concert hall, you hear more direct sound and less ambience; as you move to the rear of the hall, the direct sound gets a little quieter as you hear more ambient info. The three settings (Front, Neutral, Rear) mimick this effect quite well, and can really help give better envelopment to recordings that decode with too-tame surrounds.

So before you adjust crossovers, give the PL II Music adjustments a try. The very few times I've used PL II on movies or TV shows, it's always been the Music mode.

Best,
Sanjay

That seems reasonable, since in most setups you wouldn't find 'small' mains and 'large' center or surrounds that you would want to redirect bass to. So if the mains are small, they assume you'll have a sub connected.

Why were you trying 'small' mains and NO sub output? I was suggesting using the Large/Small setting to control if the sub output got signal from the Main or Surround. The sub would always be on.


Well, if it's re-directed but constant in level and still with enough low freq content, it could still be useful if you only look at the Left Main and Surround outputs.


Nice! Does your measurement setup allow input from a line level source, like the jacks on the back of your 950? I know, they may be buried behind the rack...

Thanks for taking time on a rainy day for us! And let us know what you find out when you get your test disk made.

The only thing to add is that when the switch is off all speakers get a full range signal AND the sub gets a copy of the signal from all speakers below 80Hz. That's the double bass. You can avoid it by keeping the switch on, but some would rather not do that.


brianca..

bergermeister:

My problem is that I can't easily re-connect my subwoofers to the LFE on the 950. If you saw my setup, you'd know why...

With the cross-mixing going on in STEREO 7, I would be very hesitant using it for any type of measurement, but that's just my pragmatic engineering side coming through

My RTA software can run on anything you plug into the computer sound input. I have a Bruel & Kjaer measurement microphone which is good +-1db to 40Khz. It has a preamp that puts out line level.

according to scott, the 950 has a fixed lp of 120hz on the subwoofer channel in 6 channel bypass. this is as it should be so as to not lose any of the original information, and this is high enough to allow outboard crossover/slope processing.

setting the switch to off sends 80hz and below from 5 channels to sum with 120hz and below in the sub channel. (i call this obese bass)

remove the cable from the 950's sw output to your sub amp. take the rca plug out of the 950's sw input and insert it into an $80 mono mic preamp, then into your sub amp. the sub will then only see lfe info (directly from the sacd player) and the summed below 80hz signal will go nowhere.

this will also work for HT, as the player will send the decoded lfe through it's sw output also. of course, this is strictly for an all speakers set to 'large' setup.

And no sub selected Thanks Brianca/Soundhound, most like me would be to forget that the first time, and go uhm something’s wrong here.

Okay JT you got me: Re: Rule of Thumb:
‘ALL’ drivers in the speaker over 6.5 = Large
Under 5.25 = Small
I have in my fronts drive units which are 2 x 7" Woofer XPP Cone "Spider-Cone" and 2 x 5.5" Mid-Woofer XPP Cone
The center speaker has dual 5.5" mid-woofers
Therefore the center falls in the gap 5.25 to 6.5 leaning to small. For sure (I) would think my center should be left small…and the Def Techs absolutely no question, at small. but....

Is there math to sum the drivers in the Fronts and divide by X or ? Rule of thumb?? Any drivers under 6.5 in the array leave said speaker at small?

Sanjay: Thank you, Joy unrelenting, something ‘new’ to play with. I went into DPL11 adjustments the first week, got lost, reset to factory default, and forgot about that option.
I’ll try both methods suggested on ‘my things to do’ list. Right now I am mightily distracted by just spinning CD’s to run them through the new speakers.

Which leads me to my next question (totally highjacking the thread). I am beginning to feel great sympathy for 2-channel nuts. (I love my surround sound and look forward to each new SPM released (if it’s not gimmicky). I tended to think of the hard core 2-channel analog guys as (coughs discreetly) old fuddy duddies.
Let those guys sit in the glow of their tubes until they have to fabricate their own needle cartridges when the market no longer produces them. I’m a modern girl.
BUT, I have found when playing CD’s, (not talking about the successful and better laid down mixes on some DVD-A’s) just straight plain old CD. That some of the ‘old’ stuff and old recordings absolutely are mixed perfectly for the ‘best’ (CD-format) experience possible when listening in straight 2-channel bypass.

For example, some of the more modern arraingments on CD’s just don’t seem optimally mixed to produce a very convincing sound stage. Last night (after my margarita at Blue Mesa) conveniently there was a Barnes and Noble’s next door. I picked up Take flight! a Bluebird Collection. This type of CD (collection of old recordings) is so satisfying to play in bypass. The soundstage just leaps out between and above my fronts, It’s as if my speakers are just gone. There are 2 cabinets sitting on the floor with nothing coming from them.
The soundstage is ‘out’ there. The boxes just sit, - to all intents and purposes dead in the water as if they have - no - connection whatsoever with that trumpet or singer over there on my living room stage.

What is it about the way the recording, mixing of a CD is done, - that creates this perfect 2-channel scenario where your speakers just disappear leaving nothing but a big soundstage behind?

Any familiar with this very nice CD will know what I’m taking about, when ‘Cat Woman’ is singing “I Want to be Evil” You can hear her standing right at a mic dead center out in front of you. etc. etc.


[This message has been edited by Smart Little Lena (edited November 09, 2002).]