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

4230 Views 28 Replies 3 Participants Last post by thewire, Mar 2, 2009

thewire

Discussion Starter · Jan 21, 2009

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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thewire

Discussion Starter · #21 · Feb 1, 2009

When I measure each channel I turn off the amps that I am not measuring. The last time I measured with the output of REW directly into my pre/pro input and I measured with the center and subs, then the center without subs and I saw no difference. It was the same for the surrounds. I will check again since I have done this before and I did not see this happen. I noticed when I checked the output of my player with a CD using Pink PN noise I made using REW, that my center channel had lower output around the crossover. It may have been some fluke that I am not sure how I did, so I will recheck.

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thewire

Discussion Starter · #22 · Feb 1, 2009

I think I know what might have caused it. I was recently using my CD input for Stereo Bypass mode and since in this pre/pro you have to do some switching or other, it may have turned off the crossover for the other channels when I tried using the 6 channel bypass mode again. I'm pretty sure I had turned off everything and switched inputs. Maybe I need to go back and disable the 2 channel bypass for the stereo analog inputs, or if I don't need to now, I should have then.

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Andysu

· #23 · Feb 1, 2009

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:

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thewire

Discussion Starter · #24 · Feb 1, 2009 (Edited)

It looks like the crossover for the center and surrounds works again. When I had switched the polarity on my center when I was testing my center with the Pink PN from the player, I get a very large dip in the 138Hz area (aproximate), but the 100Hz - 150Hz area is lower like the left and right. This what levels look like in the pre/pro after using the optimizer. I turned off the crossover on my DVD player and without doing a recalibration checked to see what changes I got in SPL.

One of my subs may have, or may not have been off when I measuring just earlier. A pair of the bannana plugs woln't turn well on my one my subs amps so they are laying inside and can fall out if I'm not careful. I measured a 105dB peak at the begining of Master and Commander at reference level.. Maybe I should give War of the Worlds a spin again.

Still not sure what to do about this center channel. I could try using one of my other mains placed horizontal to see what difference that makes. It doesn't look good at all as it is. I'm tempted to not even use it. This is with the mic pointed up in the front row center. The left, right, center are about 6 feet away and this is 1/6 smoothing.

Blue = center

Red = left

Green = right

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Andysu

· #25 · Feb 1, 2009 (Edited)

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”
80dbc

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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thewire

Discussion Starter · #26 · Feb 1, 2009 (Edited)

Thanks Andysu. I have thought about one of these DCX2496 before and it keeps looking more and more like what I need. You can see on my graphs here my subs require a bit of tweeking after the crossover as the slope is not steep enough. When I equalize from a 80Hz crossover point and eq the 90Hz bump, it results in a flatter looking response for my left and right channels.

The center I checked out and it is in phase according to my volt meter. I went inside and removed some extra damping material I added in there some years ago, and the extra dip went away. I also noticed my new replacement tweeter was out-of-phase in comparrison to my other mains. It's no wonder I was having so many problems with it. Now this makes me wonder if the extra damping material I placed behind the lower drivers in my towers that had none are not having some kind of negative effect. I'm also not sure if increasing the volume in my subs by removing the displacement caused by the plate amps enclosures is not somehow increasing the output above the crossover area to high. When I measured near field I did not notice such a bump however so it could only be something to do with my room modes at 80Hz which I was aware of when designing the room. So I might be able to correct this with a custom roll-off instead of using the eq to do so. It makes it difficult to set levels when I need to add eq after my crossover, but if I do calibrations in REW with sweeps instead of using these Pink Noises to set levels I get it looking better.

I tried this time with the polarity on all my subs reversed and I also checked the center to see that it was in-phase with the voltmeter afterwards. I'm not sure which was left or right here but the sub unequalized is purple, the response without subs of the center is in black, and the center is still blue. I will think about the DCX2496. I should be getting some tax return money sometime soon.

edit: now getting 98dB in Jurrasic park and the room sounds alright, bit loud though.

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Andysu

· #27 · Feb 1, 2009

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!?

3-D
Forwards backwards
Side-to-side
Up-and-down

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thewire

Discussion Starter · #28 · Feb 6, 2009

Andysu said:
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!?

3-D
Forwards backwards
Side-to-side
Up-and-down

I put all these holes in my stage now and the front left and right speakers now match seemless, but there is still the back wall I need to treat. There is the scene in Jurrasic Park right before Dennis is going to execute his virus on the computer, then they cut to the lawyer and the lightning strikes. That boom reverberates off my back wall like it is so easy to make my room sound bad, when in fact it sounds pretty good already. It doesn't sound like when I heard it at the theater I liked so much for that sound, and it is similar to problems I hear. So I want to fix the basics and get rid of the boominess in my room and then I will think about the eq more. :scratchhead: When I get the eq wrong it just sounds worse than no eq at all, and setting up my current eq with the FBQ takes me a long time to enter in the two filters because I feel like I have to get it just right for all four subs and every seat.

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thewire

Discussion Starter · #29 · Mar 2, 2009

Andysu said:
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!?

3-D
Forwards backwards
Side-to-side
Up-and-down

The used equalizers are sure as not as cheap as they used to be. I spent awhile trying to find one, then gave up. I did find a cheap subsonic filter to try adding to the subwoofers.

http://store.hlabs.com/pk4/store.pl?view_product=12

Adding lots of acoustic treatments seems to have smoothed out (fixed???) some of the problems. The lower ports on the speakers had been eluding me. :yes:

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