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I don't understand the BFD clipping meter. Please help.

4230 Views 28 Replies 3 Participants Last post by  thewire
I was watching Master and Commander at around +5 reference and it sounds great, but I notice that the BFD clip light comes on. I use the +4 setting on the back. I also notice that the right input meter begins to light up and clip as well when the left side (input I use) is clipped. Why does the right input meter light up? What exactly does this do to make the sound less good sounding? It does not clip my sub amps or bottom the subs. Thanks.
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I’d hate to be the room with you if, you’re running it like this. I’d need to use the ear plugs for my own benefit.:hide:

At best I keep SPL at 85db its no big deal.

Anyway at best my FBQ2496 will only reach -12db on channel A which is used for the LFE.1 track.
Channel B is used for LCRS that is sent off to the secondary sub bass extension and that doesn’t get any issues.

LFE..1 is sent directly off to the FBQ2496 while LCRS is taken from various sub bass filters and feed into the audio mixer where it then gets sent off to the FBQ2496 so I have the mixers faders to control the flow of summed L/R front centre and L/R surrounds.

If I get any issues I just make cut or modify the level of one of the L/RCL/Rsurrounds same goes with LFE.1.

I’ve played Master and Commander too many times in the past and since I had the FBQ2496 its been no where near clip unless the switch on the back is in the wrong position, then your have a few issues.

One thing I’ve noticed is crosstalk with -10db last November I think with that dreadful film IronMan it wasn’t my cup of tea it was too loud just not into loud film last year.

Well I had the -10db setting ON and whoa the LFE.1 crosstalk over to the sub bass extension and the amp for the LFE.1 was turned down while do a test. The sub bass extension wasn’t being used but it sent a nasty crosstalk :yikes:during the silly sonic boom, wow big deal!

So make sure you have at +4db that will prevent risk of damaging the subs.

Anyway I’m thinking of turning Madonna off yes this thread as interrupted my evening and you owe me a pint of paint of Milk please.:bigsmile:

You wouldn’t happen to remember the moment in the film where this happened do you?
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Come on mate you might be 8 hours behind me but its late hare in the UK its just gone past midnight and I’m willing to have a look at this issue. I need to know what part in the film, I have region 2 standing at my side and I need to know first before playing it.
Lunch okay I see, I see.

I know the moment in the film and yes I have Jurassic Park DVD JPII on THX dts laserdisc and JPIII on DVD all DVD are region 2.

I’m surprised you didn’t notice the clipping during the opening “down all hands down!”

Keep it at +4db this will prevent crosstalk and both LED indictors illuminating.

I’ll start up the SONY CRT loud up the film and run some tests at silly levels, don’t worry not a chance I’m going to bust anything in. You might want to consider DCX2496 it’s a lifesaver.
Just as I suspected -10db is bad news. “Down all hands down!” will send it into clip and +4db at best is 12db at 0db on the Kenwood KRF-X9050D with LFE.1 at 0db.

So you probably didn’t notice it until about chapter 15. You don’t have the LCRS diverted to sub by any chance?
I was having lunch.

I should have followed up on this thread. After I have looked at the back of the FBQ the -10 setting was in fact engaged. The level does not sound that loud. I was only getting a 100dB peak in Jurrasic Park at the scene where the T-REX does it's big roar at the car after they climb over the cliff and the car falls. I will recheck what I am getting now. I have changed my subs locations, used much less eq, and the gain is at -6 instead of where it was before. I have been listening to -5dB reference (THX optimizer = 74dB -75dB) instead of louder.

The scene that caused the clipping on the meter was right after I took it off pause after the scene where they must cut the mast down. The scene was over and I only hear a very faint rumble from the next room as I was in the equipment closet. I did not hear any highs or midbass from the room during the clipping. I will give it another try today (not as loud a setting on the master volume) and see if getting the setting right helps. :hide: That's a good tip about the crosstalk. :T

I think it’s fortunate that you did this thread after noticing the, funny. Well brucek did say turn it down! don’t be hero our ears are not indestructible! 130db is the limit for physical pain!

89db is the sensitivity for the control 5 at most 85db is used and that might be for all three depending on the frequency of the mix it might go higher in the lows by +90dbc and back down again.

I’ll set-up JP1 2 and 3 but 2 depending on the laserdisc player as it needs a little attention might take me while to start-up so bugger JP2 never really liked it that much.

Oh Pulse the film everyone hates inducing me, that silly moment with all the low end that is around -18 to 24db at best, yet the level of the slow pulsating computer signal or evil within it so to speak doesn’t really need to be at 120db levels I’d be surprised if most professional THX screens like the Empire would reach that level.

Cloverfield had high levels that danced up and down.
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At reference level (master volume 0) I am getting 106dB uncorrected C-weighting slow, for "all hands down" and the FBQ is at the fourth LED but was staying mostly around the third.
What is the centre channel like on its own with all-other channels muted left and right fronts surrounds and all-subs muted! What’s the SPL dbc level at the listening position.

I can switch mute any channel off or monitor the action over the LCR LF or HF to see I have any faults of kind. So mute all the other channels except the centre channel.

If you think I’m going to run the subs at this time, your crazy its flipping 1:35am.:bigsmile:
You like me like tinkering around with things. LOL

I’m just running though centre channel only at the moment with (Master and Commander) “down all hands down!” on the dialogue it’s softer over the hail of incoming cannon fire that whizzes and tears into the HMS Surprise.

Some portions of the centre I can feel. It would be better if the floor was modified with very low level sub flooring. But the height is only 7 feet 8” no need to reduce headroom, this inst a flipping cinema.

A front baffle wall will help but I have to wait until I have the dosh to spend out a £100 pounds or so.

About another 50 minutes and me and my cat are getting some cat naps because I’m shattered and its no real fun if the subs are off at this time. Time Zones suck don’t they.:bigsmile:
It’s not too far off on the graph trail and error.

Whoa gone past my bed time must have lost track of time. Successful test level comes in nicely with the dynamic EQ and some limiting and level balancing. The loud moments smoothly pass over without the ear bleeding sensation, well the unbearable loudness at chapter 4.

“Down all hands down! 80dbc to 82dbc

I like dialogue at chapter 20 “I command a King’s ship, not a private yacht!”
“We do not have time for your dammed hobbies sir”

All the soft detail is easy and the loudness is relaxed to me and others at easy while still maintaining the excitement.

Get a DCX2496 mate it is so choice for the silly price.

Levels have been somewhat changed to +15 db LF to HF LCR while dynamic EQ is set smooth out the wide frequency range and some limiting at -15db is helping for this room and it would also serve you’re needs as well without worrying about busting in the loudspeakers.

I’ll make final changes in the daytime as it somewhat rather late at the moment.

Catch you late and stay healthy
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Afternoon Wire, Its chilly here in UK! We had mild snow fall this afternoon yippy![BANANA][/BANANA]

I’d think hard if I was you. I was gutted when I saw the dbx4800 layout at the Empire Leicester Square and know this was the new word for cinema installation. I know there was no sure way I had £3K for each dbx4800 and was I depressed for weeks after hearing it in action with Transformers at 56KW!

After looking around Google I stumbled onto the DCX2496 and when I saw the price I know this would tackle some of the minor difficulties that I’ve faced over the years. Something that has most the problem solving under one lid.

It might have a few things less then the THX dbx4800 but it’s really for cinema the home doesn’t really need it unless you shamelessly rich.

A DEQ2496 is another thing on the shopping list the DCX2496 only has 9 band EQ per LF and HF when used for LCR fronts over its 1, 2, 3, 4, 5 and 6 outputs the more steeper crossover filters you use, the less and lesser the FREE SPACE because on the DCX2496 for dynamic EQ on inputs and all 6 outputs.

But when you weigh the cost of a few DCX2496 two is basic for LCR and another for surrounds and LFE.1 or surrounds and centre back.

Additional ones can be assigned for multiple surrounds and surrounds means lots placed along the walls to warp it around and defuse the sound without the THX being turned ON!

Mine has been turned OFF now for 4 or 5 months. The THX for the surrounds right adds this annoying hand-sawing like sound! That is noticeable with pink noise all-channels it sticks out like sore thumb!

I use 10 surrounds small JBL control 1, six for the sidewalls 3 on each side. 4 on the back wall because two isn’t enough I can hear the gap between the two.

Empire has at least I think 16 on the back wall? 11 for each side wall and each one is powered separately, I think, or that is what I have read, unless two or three are wired together and sent off to the Crown amp and so and so on.

Anyway I can ramble on for hours, a DCX and DEQ is cheap as biscuits when compared to £$3K.

I’d keep working on the graph a simple solution might just be eluding you?

Try standing the sub, on stool, first test it as is, then on a stool in the same area except it won’t be in the space anymore!?

Forwards backwards
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