My home cinema

[andyblackcat]

An XLR Y cable arrived early evening that I can split the SW/LFE.1 shared over two inputs on the Behringer MDX4600 that outputs to Behringer inuke3000 powering the front JBL and rear back JBL for a more ... felt like a landslide in Exodus: Gods and Kings (2014) on chapter 35 where I felt lows pressing into the backs of the seats and against my body with port air low end blowing around the room once the landslide settled down.

I like these inukes should have got them few years ago as now they have a newer edition NX series in black thou I like the design.

 

[andyblackcat]

Setting up the rest of microphone boom stands. Tiger nice heavy boom at very low price. Few more cheap XLR cables be here in few days.

 

[andyblackcat]

Experimenting with pink noise and multiple microphones with Behringer inuke3000. The power or whatever it appears clean compared to the other amplifiers Alesis RA300 being using for years.

I like inuke I may go for inuke6000.

Tuned the crossover down 20Hz L-R -48db for front/back JBL subs to see what I can see thou was hearing my ears being pressured at very soft moderate level in AM hours.

 

[andyblackcat]

Might as well call the Behringer inuke3000 the iQuake!

Well sine wave lows made me feel a little sort of sink few nights ago... iPuke careful with gain levels.

I not tried a nuke film yet thou have plenty of them.

Tried mountain landslides and tsunamis, Exodus: Gods and Kings (2014)

Trying the classic grand sub bass daddy Earthquake (1974) at mild soft level.

Lowed the crossover settings lower down with steep L-R -48db sort of experimenting with Earthquake.

The LFE.1 is at the left of the in-room spectrum lab microphone pick up. The response on the right is the five-screen channels playing.

 

[andyblackcat]

Sat at the back row centre middle for few moments of Earthquake and it made me feel queasy with crossovers settings now at ...
Front JBL 22Hz L-R -48db gain +3.0db
Rear back JBL 23Hz L-R -48db gain 0.0db
But least I know its working.

Gain level raised on the MDX4600 +5db each

I had pleasure of seeing Earthquake 70mm at local ABC screen 1, 'Feb 75, x4 times in Sensurround over several months for 79p. You won't get real cinema at great value today when back then for child it was 79p, today its £20.00 for child.

I not even re-wired all the bass shakers attached to the seats yet not even used them for a year or so. May wire them to other amplifiers and set the gain levels accordingly so they operate within safe levels.

 

[andyblackcat]

Spent 8 hours rechecking the horns to "keep on listening" with sine wave tone checks and looking at harmonic frequencies produced few cycles above the generated sine wave tone.

Its long and tedious and my arms are aching after 8 hours a little trembling in my hands. I take another crack it another day or get out one of the other few horns I have left to see if I can ... Well I would be totally surprised if I can get a transparent overlay of frequency and phase.

Jiggle the diaphragm to the side up and down easing it up delicately tightening down the three screws in random sequence to reduce the harmonic or even giving the diaphragm gentle tapping on the side to nudge it into place. Then looking at pink noise then running a repeated frequency sweeps and deleting the not so good ones and using one as sort of kind of template even thou the piece is not going to be like a jigsaw puzzle the piece of frequency have to all fit together.

Its like SWR-ing a CB radio antenna to have good 1 to 1.5 SWR though all bands and modes SWR of 3 is near bad and that's a lot of hassle if having to climb up a ladder same with a mobile antenna tweaking the antenna tiny fraction up and down.

I guess next I be checking voltage frequency output from amplifier even thou its going to be flatter than horn.

 

[andyblackcat]

I was right, Anakin the Jedi cats are taking over.

My furbabies wanted to see what I have been up to all day when packing it up for the night started climbing over the work bench and other JBL speakers laying on the floor.

 

[andyblackcat]

The other x2 XLR cables arrived yesterday. I do the extra multiplex microphone later in the day.

 

[sterling shoote]

Aren't those JBL's from their Control Series. Back in the late 1980's and mid 1990's I used Control 5's for my 5.1 system using a JBL B-380 for .1. I replaced the mains with JBL L100t3's and surrounds with JBL L20t's. I can not say that it sounded better for movies. I see that those Control 5's are still made today and that they sell direct from JBL for about $169.99 each. Seems like the way to go for a great home theatre experience for little money.

 

[andyblackcat]

The 1, mid 80's 5, I think those are mid late 80's the 10 is I think late 80's the 12SR I think appeared around 1990 as I didn't see them until 1991 in PA music store around £800 each I think at the time that also had 15" sub box that mounted to the 12SR or stand alone tripod.

Surprised they still make 1 and 5 the 5plus stopped being made but JBL carries on with other control series. I like to get few of the SB-5 owned one in past and that was an okay TCB sub would have liked to have few of them around 1991 as the large PA ones would take up too much floor space.

 

[andyblackcat]

Now I am feeling skeptical about the sweeps.

Direct frequency sweeps to see what the frequency roll of is like.

Processor output though the THX sound system on (processor monitor) This bypasses the DCX2496 its just signal passing though the THX to the computer.

Processor to DCX2496 and amplifier with crossover switched off on the high end expect for the lower end where crossover is switched ON at 447Hz the sweep continues though to the high frequencies but starts to steadily roll off where it should be continuing to at least flat.

The X-curve ISO 2969 starts rolling off at 2Khz but the roll off curve of the frequency is way too steep.

With a horizontal line placed on the direct processor sweep I see a roll of starting around 6Khz.

Now to rule out possibility of which is causing the high frequency roll off as I may have to re-align the JBL 2371 horns again.

1) Is the amplifier rolling the high frequencies off or maybe in some small way rolling the high frequencies off?

2) Is the Dolby CP65 rolling the high frequencies off?

3) Is the Behringer DCX2496 rolling the high frequencies off even thou the crossover for the high end is switched to OFF its only switched ON at crossover point between the bass frequencies and where the high frequencies start to take over at.

4) is it the computer rolling off the high frequency due to its sound card type?

Its one or more of the above ^ ?

I need to run a frequency sweep direct sweep looped though the computer to start eliminating one by one which is creating the roll off.

 

[andyblackcat]

Took a direct pc to pc or looped a lead from output to input.
One sweep 0Hz to 20.000Khz
Second sweep 0Hz to 24.000Khz as that is the max limit of the REW frequency sweep.

Yeah that's more like it.

 

[andyblackcat]

Another frequency sweep was from pc to the Denon AVR-1602 which is used as a direct input to power LCR HF horns. (I use another AVR Yamaha to power the left-centre right-centre LF/HF) but these AVR's will be soon replaced with pro amplifiers.

So the Denon AVR-1602 is rolling off the high frequency at little past 2Khz which seems sort of normal but maybe a bit unnecessary as this causes some confusing errors in in-room frequency sweep testing.

So I may need an amplifier that I can test that has a flat response to redo the alignment of JBL 2416h diaphragms.

 

[andyblackcat]

Started with centre channel horn no reason to start with it first its just there.

Cleared yesterdays PEQ settings in the DCX2496 and started fresh again only adding a lower crossover slope Butterworth -6db 3.04Khz added in some PEQ at 3.04Khz with Q quality 1.4 then lowed the gain level down -10.0db and with each testing I raised the amplifier gain to compensate for lower SPL db level.

Then added in LPF 12db 8.32Khz lowered gain by -5.0db
Checked the sweep which isn't here as I deleted it and its the last sweep test I checked that may get altered again.
I added in HPF 12db at 607Hz lowered gain down -15.0db and raised amplifier gain up to compensate and gave it a listen with STAR TREK The motion picture laserdisc DVD-RW theatrical Dolby Stereo mix.

Better its better. But will have to double back check with crossover slope even though the lower, lower Hz isn't going to break the driver its far too lower down.

I still need to take one many other JBL 2371 horns with 2416H 8ohm and do a direct frequency sweep of all the other amplifiers I have to see which one is flatter on the high end?

Guessing the new Behringer inuke3000 thou a gentle amount of gain power will be used as I don't want to nuke my JBL horns.

Then again might be one my vintage Marantz 1050 that has flat earth frequency high end? I have to check them all and that is going to take several hours of direct pc to amp testing.

 

[andyblackcat]

Had another go at the other SDDS D3000 and managed to reformat it with all gain levels EQ set to 0.0db default and configure set-up the AUX 1 and AUX 2 for use.

There is a Matrix setting on the processor that can shuffle channels around and that has been set to Matrix 1 on AUX 1, 2 and will be readjusted once I find some rack space for it.

The fan will be disconnected and the top panel lid removed so heat can vent upwards away from the processor and run silent.

My first D3000 sits on the floor and will be reinstalled later in the day once I give the processor a run though but seems all normal and fine.

 

[andyblackcat]

Experimenting with the microphones positions one facing forward the other two in opposite directions.

 

[andyblackcat]

Back around May, picked up a Penton - gb20t cheaply to see how it would fair for an overhead experiment?

I disconnected the transformer inside it as I didn't need the "cybertron" reducing the voltage. It was sort of okay that it sounded in circle like hemisphere.

Weakness was the full range 8" driver which is only suited for public voice announcements or very soft ambiance music that is often heard in shopping centres. Maybe if fitted with another 8" that fits it depending on the basket diameter and with some extra padding inside it to reduce any possible resonate noises. Its sealed so no port on it.

I tried a simple Dolby Stereo moment from Star Trek the motion picture (1979) with V'ger's highly charged electrical lighting moving across the LCR and into the matrix mono surround sounded fairly good and like above if fitted with better 8".

data sheet of specifications and frequency response
http://www.pentonuk.co.uk/…/downloads/GB20TENC_datasheet.pdf

 

[andyblackcat]

Installing the other Sony SDDS D3000 for tomorrows other install upgrade.
Finding rack space in these small 24U frame racks has served well over the years with gear being shuffled around in them.

The Dolby remote fader will be installed at the side of the rack once finished.

 

[andyblackcat]

DB-25 adapter boards for the wiring of the second SDDS processor.
I have to get the multi-meter out and read up on the Sony D3000 manual for wiring for the pins and get some cables made up

Sooty was sort of curious at what I was up to?

 

[andyblackcat]

Redid it with screw fitted in place and metal drill bit used on the cordless drill to make the hole a faction wider so that the screws threading can screw into place.