Small but perfectly formed JBL home cinema

[macaroonie]

The spray tack is just there to seal the edge of the board and allow the gaffer tape something to adhere to instead of dust. Hey if you don't believe me about the rug get some of your foam panels if you have any left and lay them out on the floor in front of where you sit.
Report your findings

[JBL 4645]

I wouldn’t put a rug up in the room if you paid me to.

I’m not going back to rugs much less carpet stuck on walls its very unattractive.

[JBL 4645]

I wasn’t aware my new digital camera had panorama mode it’s a bit digital noisy.

[lgvenable]

A friend was down in Kentucky late year, bidding on quarter horses at a horse auction. He lost, but to someone he thought looked familiar. Then he realized....it was William Shatner without his rug!

[JBL 4645]

A friend was down in Kentucky late year, bidding on quarter horses at a horse auction. He lost, but to someone he thought looked familiar. Then he realized....it was William Shatner without his rug!

LOL That's right he's into horses.

[JBL 4645]

[JBL 4645]

Basic Instinct has had multiple runs this week and still a brilliant thriller 19 years on that works very well on a who done it. Well I know Catherine Tramell did she’s the ice pick lady a cold blooded psycho killer.

One small change I made today about from doing EQ to get the bands as flat over the LCRS with limited amount that is on hand at present use new version REW RTA I’ve managed too get 98% flat on most channels if I had 1/3 for LCR I could get it tightly flat. The sidewall is not as bad as I have the GEQ3102 for the sides the other EQ for rear back and PEQ EQ on DCX for LCR LF/HF

Oh, the change its much. I stacked up the corner with some loudspeakers that are not being used and its managed too lift the shallow dip up from 70Hz 80Hz 90Hz and 100Hz. I can’t block in the corner as of yet since I haven’t placed absorbent material behind the baffle wall and I need too (unscrew remove the plasterboard) so I can easily work behind it.

Chapter 24 the car chase sounds incredibly tense with composer master Jerry Goldsmith bass timpani percussion beats nicely. Sound effects of Nick’s car driving up the hill ramming into lampposts and other objects is clearly heard from side to side.

Roxy driving the car into Nick lifting him up onto car and over, landing face down. Wow that is wicked stunt, hope the stunt man didn’t get hurt on that take. The LFE.1 come in with an extra body weight slam when Nick lands on the ground the bass over LCR knocks into him then body fall on LFE.1.

[Audiobeer]

LOL That's right he's into horses.

Actually he was aquitted on those charges!

[JBL 4645]

Actually he was aquitted on those charges!

What’s that then sex with horses .

I used to get a ride on a nice shire horse, many years ago. I think he was called hector?

[JBL 4645]

I’ve been outputting at sine wave tones while monitoring the SPL db at close range to bass/mid and HF over narrow range of frequencies.

Since the sine wave is monaural output I use Dolby pro-logic to output to centre and bypass stereo to test left and right fronts.

I can only adjust so many bands and dial in so many bands on the DCX2496 since L-R-24db is taking up most of the CPU on the DCX2496.

Tones I tested while setting for 0db or within 0.5db range setting. I used narrow band filters some bands needed quiet a bit of cut to bring each one within 0 to 0.5db.


63Hz
124Hz
161Hz
249Hz
499Hz
1.000 KHz
1.125 KHz
2.003 KHz
2.251 KHz
3.180 KHz
4.020 KHz
8.140 KHz
16.010 KHz

Re-listened to Ice Station Zebra (1968) which has a lot of dialogue panning centre front to half left/right to hard left/right.

Chapter 7 where Jones is introduced to the captain the EXO voice is panned off-screen to left front then locks to centre when he’s visible on screen in the centre position. Jones voice is panned to left or rather half left. As captain Ferraday leads Jones off the bridge to though a corridor Jones voice slowly moves outwards as if he and the captain are actually walking thou the hatch then the voices lock to centre on the next shot smoothly from the last shot on the bridge without any jumps in the sound as the baffle wall, keeps it nice.

I’ll try this approach with subs and then with surrounds by re-plugging the surrounds from their normal out and plugging them into the front outputs and use the Dolby pro-logic to output centre back when needed. The testing might take several hours extra as testing the fronts took a few hours of walking around with SPL db metre and going to bed room and selecting the next frequency on the sound generator.


Chapter 27 has neat bit of mixing as Jones looks around Zebra for the film canister he explains to the captain about the film while walking around his voice smoothly pans over LCR in one of scenes Jones walks down a few steps and the high to middle end drops off a bit and gives the impression he’s walking down a few steps off to right which made look downwards towards the right.

Jones than walks back up steps and again the voice has the same muffled slight cut off in the mix that gives the illusion of kinder height. The full range of the voice than comes back in.

[Jonas_h]

Aren't you going to put some absorbing material on the baffle wall? I cannot see what you are gaining by having the baffle wall as it is now.

Have you ever used REW for measurements instead of test tones? With REW you are getting a continuous measurement instead og discrete sine waves and REW can recommend filters for a specific target curve in your room and it can predict the response.

[JBL 4645]

Aren't you going to put some absorbing material on the baffle wall? I cannot see what you are gaining by having the baffle wall as it is now.

Have you ever used REW for measurements instead of test tones? With REW you are getting a continuous measurement instead og discrete sine waves and REW can recommend filters for a specific target curve in your room and it can predict the response.

Yes I am and I’m a little behind schedule at the moment. When something crops up on ebay I tend to watch and buy it.

Also I like to use the same martial linacoustic its kinder hard to find in the UK I used at least 8 or so keywords I even took a crack at ebay UK and nothing.

I might have to look for something close that will be soft and spongy absorbent to cover the plasterboard uniformly.


Yes I have REW on the pc and used it but I thought I‘d try a new approach because the sweep is nothing more than sine waves accelerating at fast speeds.

I took my time I wasn’t going to be impatient because I have used REW till almost blue in the face and results wasn’t getting me anywhere its neat device to use and I used the sound generator to output the tones so I can centre on tones that’d would normally be on 1/3 EQ I can’t dial in 31 bands per each channel on the DXC2496.

I might get away with using -6db crossover slopes and be able to push for 9 PEQ bands per LF HF over the 6channel outputs total of 19 bands per LCR still a little less from 31 bands.

I’m also behind getting FBQ3102 31 band EQ I have GEQ3102 that’s being used for sidewall surrounds at present and other mismatched EQ that will soon be removed/replaced with FBQ3102.


So far the smoothness of listening to Ice Station Zebra most nights now, sounds smooth first time I did the EQ last week to last nights listening I like it when the captain and Jones walk off the bridge to left front the smoothness of the dialogue panning sounds natural then snaps clearly back to centre.

I’m going to re-listen to another Dolby classic in moment on laserdisc and DVD because that was giving me headache week before last the sound pan was miles off the mark and I tried several ways until last week when frustrated with listening to Ice Station Zebra. The baffle wall still works, but if the EQ is on the piss its going to have bright passages in the centre and half dialogue pans won’t make you look and listen to that direction (as if I had two people standing ether side or me) I’d be turning around to look at that person.

The Towering Inferno has lot of half pans as Newman and McQueen exchange dialogue as the camera follows the two of them outside the tower while walking into the lobby.

[Jonas_h]

But thats where I think you're wrong: You will never be able to EQ the system well, by only using a 31 band EQ. And the measurements you do with sine's at the frequencies you mention, does not give a clear indication of the overall response of the system.

The filters which are calculated by REW uses multiple parametric eq filters which together achieves the response you want. This cannot be done with GEQ's. You are already using the DCX's which have this capability.

EDIT: You keep on mentioning that you do not have 31 bands etc... Why do you want to use that many filters? The optimal solution is as little filters as possible, as these affect the phase response of the system. So you want to minimize the amount of filters used, and this is exactly what you can do with REW and its PEQ calculations. I have used at most 9 filters for each speaker in my system, and this gives me the exact freq.response I am looking for.

[JBL 4645]

But thats where I think you're wrong: You will never be able to EQ the system well, by only using a 31 band EQ. And the measurements you do with sine's at the frequencies you mention, does not give a clear indication of the overall response of the system.

The filters which are calculated by REW uses multiple parametric eq filters which together achieves the response you want. This cannot be done with GEQ's. You are already using the DCX's which have this capability.

EDIT: You keep on mentioning that you do not have 31 bands etc... Why do you want to use that many filters? The optimal solution is as little filters as possible, as these affect the phase response of the system. So you want to minimize the amount of filters used, and this is exactly what you can do with REW and its PEQ calculations. I have used at most 9 filters for each speaker in my system, and this gives me the exact freq.response I am looking for.

Oh, I agree. I’m doing this as experiment and it seems to be working so far so good. So I’m not going to knock it.

One thing I haven’t tried yet and not sure if I can make a lead longer enough to get the SPL db meter close to JBL as the pc is some 6 meters away.

I’d the test first without then look at the close range response over each LF LCR and HF LCR one at time to see what lumpy bumps I have. The REW has filters for the DCX2496 and might be easier to calculate.

I did another test same thing on the big JBL sub because one thing I hate is excessive boom, boom that is unnatural to the mix. Doesn’t matter where it is could be 35Hz where it peaks a bit or above 60Hz and its annoying to listen to when it sounds most of the time.

I went though 18 bands the rest I use to filter off any high frequency hiss that leaks from the MDX4600 though to Alesis RA300 and it works very well, so the sub is hiss free with filter up at 2KHz and one below it at 1KHz with -36db cut Q 75 reduces any middle range dialogue filtering though and the SW-Remix sub mode that I use for DOLBY STEREO 4.2.4 mixes has its own 80Hz crossover -24db.

[JBL 4645]

I like chapter 5 for soft ambiance between Indy and Belloq as Indy places a bottle down on the table sounding to right front its partly in the centre but sound positioning is to right to create that cool sound like of being there.

Indy then pulls a chair out that scarps across the floor left front the cute Nazi spy monkey squeaks track pans from centre off to right.

Chapter 6 when Indy walks into a tent to find Marion that has deep John Williams tympani that isn’t anywhere as deep on the THX DVD its been slightly reduced trimmed SIGH listen to German track and its there only downside is its not presented in DOLBY STEREO 6channel discrete only 4.2.4 matrix.

The laserdisc is sweet and juice DOLBY in PCM.