JBL Synthesis - Something BIG is on its way...

[nlsteele]

For movies, one wants not to be able to localize the surrounds, right?
At times, you do want localization, like when a plane is flying from the left rear to the right front, for instants.
But in a movie like Twister, when you're in the middle of a tornado, you just want the sound all around.

If I'm not off my rocker (pardon me if I am) in-phase sound sent to a particular channel should be localizable intentionally, in-phase sound sent to a pair should be localizable to the centerpoint between the two, and out-of-phase sound sent to two should be un-localizable. If your surrounds were creating too many reflections it would make it more difficult to differentiate the conditions of in- and out-of-phase, especially with the contemporary surround and rear surround arrangements of 7.x.

[jblsound]

If I'm not off my rocker (pardon me if I am) in-phase sound sent to a particular channel should be localizable intentionally, in-phase sound sent to a pair should be localizable to the centerpoint between the two, and out-of-phase sound sent to two should be un-localizable. If your surrounds were creating too many reflections it would make it more difficult to differentiate the conditions of in- and out-of-phase, especially with the contemporary surround and rear surround arrangements of 7.x.

If connected properly, all the speakers are in-phase. But like the two examples I mentioned, the plane would be localized, but if the sound effect is being in the middle of a tornado, the sound is whirling all around. There might be a bit of localization, but mostly its mass kaos.

There are some DVD-A disc that have the sound panning across the back and across the fronts creating a racetrack type of sound image, but that's not the norm.

[nlsteele]

If connected properly, all the speakers are in-phase. But like the two examples I mentioned, the plane would be localized, but if the sound effect is being in the middle of a tornado, the sound is whirling all around. There might be a bit of localization, but mostly its mass kaos.

There are some DVD-A disc that have the sound panning across the back and across the fronts creating a racetrack type of sound image, but that's not the norm.

Yeah, you're right that the poles of the speakers would be physically in-phase, but you can still send an out-of-phase signal to two of them (reverse polarity for the signal to one channel of the two) ala the THX optimization tests on any THX disc. So for a scene like the tornado in twister, you can send out-of-phase signals to the multiple pairs, creating an entirely unlocalizable, but fully surrounding sound.

[JBL 4645]

We watched the first part of Master and Commander, and near the beginning you see the ship's bell being rung in the middle of the screen. I exclaimed, "Man! That sounds like it's ringing right out of the bell."

Pans are very good, but will be even better when the fronts are fully calibrated.

And the distance from screen! Would you like to have front row because the nearer the wider and wilder the fronts sound even in cinema. The further you move back the stereo starts to narrow.

I’ll give that moment a another listen again!

Jesus Christ! I just back home and have bath and cat is going batshit! running around like blueass fly bumping into doors! See what I have to deal with?


Edit: 10:20 hours UK summertime

The ships bell is heard centre with half of its sound on front right left is free from the bell sound it kinder sway rather like Doppler shift to give the since of moving sound.

A few voices are heard over C/R no difficulty at 9 feet to present listening distance.

Then again I can mute anyone of the LCR LF/HF fronts for monitoring or figure out a way of adding a little delay on one of the HF to make some pain the ass Dolby stereo 4:2:4 front LCR work without having to strain to listen so to speak.

[jblsound]

Yeah, you're right that the poles of the speakers would be physically in-phase, but you can still send an out-of-phase signal to two of them (reverse polarity for the signal to one channel of the two) ala the THX optimization tests on any THX disc. So for a scene like the tornado in twister, you can send out-of-phase signals to the multiple pairs, creating an entirely unlocalizable, but fully surrounding sound.

Same with DVD setup disc. It sends an in-phase and then an out of phase signal to each pair of speakers, working around in a circle, for the purpose of checking for proper phase setup. I mis-read what you were saying.

[nlsteele]

I mis-read what you were saying.

That just puts you in a lot of good company.

[JBL 4645]

Same with DVD setup disc. It sends an in-phase and then an out of phase signal to each pair of speakers, working around in a circle, for the purpose of checking for proper phase setup. I mis-read what you were saying.

It’s not too hard to spot the difference once you know what to listen for.

Like the phase test for centre back when listening to the signal (in and out of phase the outer phase goes to the matrix rear on Dolby pro-logic decoder or the overheard surround channel!)

If you also placed the signals from LCRS into mixer and use a single output to one speaker and play those test singles it’s somewhat different.

There’s manufacture I think its called Leader who make some rather costly audio test gear I mean costly. Its got some fancy features on some of the products to align the sound system up.

LEADER
http://www.leader.co.jp/english/index.html

AES E-LibraryVisual Monitoring of Multichannel Stereophonic Signals
http://www.aes.org/e-lib/browse.cfm?elib=7836

[Titanium Dome]

Well, I'll settle for the JBL DACS and be happy.

As for sound in the surrounds, it needs to be both localized and not localized, depending simply on the intent of the mix.

[JBL 4645]

The art or technique after a bit of trail and error was (the spacing of the monopoles along the sidewalls) the cost in the long run was no drearier than pair of dipolar/bipolar surrounds for x10.

Three on each sidewall spaced out.

Centre back a bit tighter closer together for soild centre back without that sodden hole its soild in the middle and to the outer sides.

I think you should first mute LCR/sub bass and just listen to the monaural matrix surrounds from Dolby stereo 4:2:4 mix or DVD that has monaural surrounds there are plenty out there from the 70’s 80’s era only handful was realised with split-surrounds/stereo surrounds.

Also you won’t need the THX turned ON as this eliminates the need. I haven’t used the THX ON for months now, plus you have that annoying hand sawing effect on right surround channel if you play some pink noise all channels and mute LCR you’ll hear it

That Chris guy should be able to get the tone spot on to be within a few 0.5 db or what ever spot on so the hiss from centre matches the hiss or close enough in frequency otherwise too much from centre might mask the surrounds and vice-versa.

The Blues Brothers region 2 DVD mobile as it flies over the bridge has music on the split-surrounds followed by roaring overhead duck! Effect!

What are we doing here?

You promised you’d visit the penguin the day you out.

Yeah. So I lied to her.

You can’t lie to a nun

We gotta go in and visit the penguin.

No fu&king way.


Oh, no I thought it was suppose to be five years.
Didn’t you get five years?
No, sir, not you.

Interesting sound fact is the fogy LCR dialogue track on The Blues Brothers Dolby 5.1 mix. It has mildly spill over to left/right but its clearly focused on centre and this type of mix is also found on early Todd-AO The King and I South Pacific The Sound of Music West Side Story soundtracks and newer later few Dolby stereo 70mm like Cocoon Apollo 13 Star Trek II the Wrath of Khan Wargames and a few more.

Come on. Seriously, the food here is really expensive. The soap is f&*_king $10! LOL

We’re on mission from God.
How much for the little girl?
What?
The women? How much for the women?
Your woman I want to buy your women.
Your little girl. Your daughters. Sell them to me.
Sell me your children LOL LMAO
Maitre d’!

This film cracks me up!

The fu*^king Nazi party PA horn is heard over LCRS
I hate Illinois Nazis.
LOL

They all jump the bridge LOL we’re gonna kill that son of bitch.

(Ray Charles) chapter 22, Ray’s Music Exchange has nice beat without sub bass extension as the LFE.1 adds its own discrete beat kick.

Twist it shake it, shake it baby.

Chapter 23, The flamethrower was decent enough as the flame licks out from centre with mild left/right then whips over the surround or around my ears makes me flitch. There’s defused and stereo effect happing at the same time.

Hey Jake, there’s got be at least seven dollars change here. WTF! They just got blown up for second time and they don’t bother to ask questions? LOL

To monitor the city, county and state police on their CB’s LOL
Mr Blues is gonna f%^(k up.
And when he does…LOL
He better pray the police get to him before we do.
[Nazis smilling]

Oh, no things are about to get ugly. LOL this films a classic laugh. Can’t say much about the sequel thou it was pants.
The Good old Boys LOL

We're talk to Bob.

Back in 5 minutes!

Chapter 44 the guns cocking along the LCR with a few single cocking sounds on surround left and right. Whoops! Jail House Rock LOL
The discrete isolated instrumental on the split-surrounds beats along with the fogy vocal LCR and the accompanied LFE.1 supports the rest of music nicely to the final end credit role over black.

I’d like to add some LCRS sub bass extension and keep LFE.1 discrete. I need you, you, you!

[Allanvh5150]

[Get The Blues Brothers laserdisc spinning unless you have region 1 DVD?]

DVD region code?

If you search the web for "how to unlock DVD region codes" you will most probably find the code to unlock your DVD player to allow you to play DVD's from any region.

Allan.

[JBL 4645]

[Get The Blues Brothers laserdisc spinning unless you have region 1 DVD?]

DVD region code?

If you search the web for "how to unlock DVD region codes" you will most probably find the code to unlock your DVD player to allow you to play DVD's from any region.

Allan.

Regional hacking is like looking for needle in haystack. I don’t have to happen the codes or proceeded to start with my Pioneer DV-525 as its strictly region 2 and I think a few other regions will play expect region 1 it will play region 0 no problem.

I have few of the same title on disc. It’s uncommon for someone in the US to have few region 2 DVD LOL its very common in the UK to have region 1 titles or (NTSC laserdiscs) due to release dates of the past.

[boputnam]

...and the sub output changes to this. Woo-hoo! Solid at 20Hz and heading down into the teens.

Interesting filters.

Hz b/w gain
20 1/6 -0.5
39 1/12 -1.5
40 1/6 +6
54 1/24 +4
54 1/6 +5
64 1/12 -6
80 1/24 -2
102 1/6 -9
155 1/3 -9

That's a total of nine filters on one band pass - and there are redundant filters (e.g., 54Hz; where one might work) and adjacent competing filters (e.g., 39Hz (-1.5 dB) vs 40Hz (+6 dB); again, where a different approach might result in one filter...). I find this a bit strange, or extreme to me, at-the-least. And this is for a +2.5 octave bandwidth? I'm curious what the phase response of that band pass looks like...

So, some questions?
- Are the subs being EQ'd as a group?
- This filter set is from the room response - so this is the filter set on the inputs to the subs?

I'm guessing those answers are "yes", largely due to the whopping ±2.5 octave +5dB anomaly at 500Hz in your "pre" plot - that's well above the sub HPF..

My preference would be, if the capability is there, to EQ each sub separately, close-in. This would be done after the crossover, on the input signal to each sub. After that, you can test the entire room with only the subs lit, and EQ the inputs to the crossover. Does that make sense?

In SR, we EQ the signal to each band pass to "tune" each cabinet's response first - mitigating undesirable cone and cabinet resonance(s). Typically, this is three, maybe 5 filters at-most (depending on the bandwidth of the band pass). Then, once each band pass is done, the outputs are all opened and we look at the system response for frequency and phase - again, close-in. Typically, there will be (undesireable) phase anomalies (discontinuities) at/near the crossover points. The question becomes, if those perturbations are result of some of the filters, can we lessen the magnitude (and number of) filters to achieve a better phase response while maintaining the desired response curve. Not easy stuff.

Once that is done, we look at the room response to each band pass (say, all subs), and add filters to the overall input signals (before the crossover - the way you'd use a GEQ). If we have controlled the response of each individual band pass, the overall EQ required is significantly less.

The brief before/after bass-EQ adjustments also seemed effective in "tightening up" the bass and reducing apparent room influence ...

Perfect.

I have performed a similar (if less comprehensive and time-efficient) EQ process with an analog parametric EQ at home. Having hardware to run averages (and probably more) with 8 positioned microphones is a distinct advantage.

But Dave, are the 8 mics "merely" measuring different locations in the room, and is all this done without first measuring cabinet/band pass responses?


My point in all this, is, you have multiples of the same cabinets deployed around the listening area. If you are able to first mitigate their undesireable frequency responses before they excite themselves (and the room) your overall abiltiy to control the room response is dramatically increased, and with fewer filters (= better overall phase response).
.
.

[grumpy]

You bring up some good points, and I could guess in responding, but this
was the first time I had seen this system and was a guest, observing the
process.

I'll hazard a guess at one item anyway: If I recall correctly, the sub outputs
were indeed measured with multiple mics (which were placed mostly on seats,
one was fairly "near field"), but sounded driven full-range with the test
signal, so ... the resulting cabinet -and- room responses were then adjusted
to provide the desired composite flatness, level, and crossover slope...
probably delay too. I don't recall if they were measured one and then the
other, or simultaneously... perhaps Doug remembers. The point seeming
to be to achieve the desired acoustic response at typical listening positions.

I follow the SR procedure outlined, and I like to have the nearfield response
of whatever I'm working on too, but I'm not sure in an HT environment
that the ultimate outcome would be much different... other than room
modes for 2 18" subwoofers, the whole room is almost nearfield

There's another possibility... these are all JBL-Synthesis components...
whose responses may very well already be preset somewhere in the
software of the measurement system.

Good question for Chris, in any case.

There -was- an abrupt knee in the "final" EQ curve that seems might cause
a corresponding phase issue, but it was pretty low in freq (IIRC).

[Titanium Dome]

The one thing I recall is that each of the system components and the system itself had to be identified to the DACS before the process was initiated. For example, it was important to identify S1S-EX rather than simply S1S, or, worse, "subwoofer," etc. I suppose the DACS could read/identify the SDP-5 and SDEC-4000P/X units via the network interface, but not the loudspeakers or amps. It needed to be told in order to access the right profiles for the compiler.

Beyond that, I couldn't hazard a guess as to what was going on.

[Mike Ronesia]

Beyond that, I couldn't hazard a guess as to what was going on.

Crazy voodoo magic would be my guess...