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Equalization of TC-2000 sub.

5K views 41 replies 2 participants last post by  krisdz 
#1 ·
My sub chain: Outlaw 990 (LFE XLR out), BFD 1124P (XLR in) (XLR out), EP-2500 bridged (XLR in)
The Outlaw 990 has XLR outputs but I can’t find the XLR outputs level spec in the manual.
It is: +16 dBu at +4 db or +2 dBV at -10 dBV?
Any one knows those parameters?
I guess I can experiment with the switch on the back of BFD (+4 -10) but it will be not sincerity.
The next concern is my sound card, how good it is? Good enough?
How can I reference the sound card?
I read those posting about using the BFD, Room EQ and CM-140. They are strait forward and thank you very much for the enlighten. Especially the BFD setup now is clear and easy.
I will be appreciated if someone will share hands-on comments about the whole process of EQ a sub
 
#2 ·
The Outlaw 990 has XLR outputs but I can’t find the XLR outputs level spec in the manual.
It is: +16 dBu at +4 db or +2 dBV at -10 dBV?
Any one knows those parameters?
I looked at the poorly written specifications of your processor and you're quite correct to be confused. I suppose they think we're mind readers. Usually if the single ended level is offered, you will assume the balanced is simply twice that level. But they haven't spelled out maximum or nominal too clearly so it's hard to say.

Anyway, it's of no importance, since the BFD conveniently provides input level VU meters (I hope those who think input level indicators aren't an essential item read this).

If you press and hold the IN/OUT switch of the BFD until it flashes, the VU meters are now reading input level (rather than their usual output level indication).
Set the BFD rear operating level to -10dBV (which represents a nominal level of ~315mvRMS) and a maximum level of +2dBV (which represents a level of ~1.25vRMS).
Set your LFE sub output from the Outlaw at neutral trim and play a movie that provides a lot of bass (War of the Worlds, Transformers, etc) and watch the VU meters. Be sure to play it at the loudest you would normally ever use.

If the VU meters are continually in the red, drop the trim a bit and see if that's OK. If not, switch to the +4dBu setting (which represents a nominal level of ~1.24vRMS) and a maximum level of +16dBu (which represents a level of ~4.9vRMS). Repeat the experiment.....

The next concern is my sound card, how good it is? Good enough?
How can I reference the sound card?
Most any soundcard is good enough as long as it has a line-in and line-out jack (most laptops don't). What do you mean by 'reference' it? You create your own calibration file to make up for any response anamolies....

brucek
 
#3 ·
[/QUOTE] What do you mean by 'reference' it?

I thought there is reference sound card which could be used to compare against it.
Instead I can create calibration file for my SC. I did that. Now I’m waiting for the cm140.
Also I play little with the +4 and -10 BFD but it is not conclusive. I will play more with it tonight.
 
#4 ·
Hi brucek
I did test the Outlaw 990 and BFD.
That what it comes out:
Total volume control -10 dB playing Star Wars III first scene.
It is very loud; usually I’m listening between -15 dB and -12 dB but I can crank above -10db another 2-4 dB before my speakers starts clipping.
Blinking BFD input LED
990 LFO out +10 dB and BFD +4dBu = yellow LED on BFD, occasionally very briefly red
990 LFO out 0 dB and BFD -10 dBv = yellow LED on BFD, occasionally very briefly red
Looks like It is 10 dB (according to Outlaw dB scale) difference between +4dBu and -10dBv
It make sense to you?
Kris
 
#7 ·
What will be the BFD output -10 dBv or + 4dBu?
The level will be whatever level you feed the BFD. It simply passes the signal through (subject to any filtering gain or cut).
The 2500 accepts a very low input level for a pro amp to provide maximum output. It is stated as 1.23vRMS, which is exactly the maximum output level of a BFD when using the -10dBV switch position - small coincidence since the two devices are made by the same company.

The 2500 has input control pots to dial down inputs that are too high.....

brucek
 
#11 ·
Before we continue, allow we to make some suggestions about graphing.

The little floppy icon in the lower left hand cornner of the REW graphs is to SAVE graphs so you can post them. Use 800 bips wide.

Set your vertical axis to 45Hz-105Hz and your horizontal axis to 15Hz-200Hz. Use the Graph Limits icon to enter these limits and every time you measure you can go back to this icon to reset to those limits with a single click..

You can show graph comparisons on the All measured tab in REW.

Repost your graphs as outlined above.

So far it looks like your before response is better, so I'll wait until you repost. :)

brucek
 
#13 ·
I think you may have to move your sub around a bit to try and smooth the response out a bit. It certainly is a bit of a rollor coaster.

Again I'll ask you to post the graphs that REW creates from pressing the floppy icon in the lower left corner of the graph. It will be much easier to see. Do you see the icon I am talking about? :)

Text Line Font Parallel Diagram


brucek
 
#19 ·
All the graphs are the sub only and my crossover is set to 40 Hz. I have big mains.
I’m feeding the BFD directly from PC and RAW
There's no evidence in your graphs that reflects you're using a crossover at all, but I guess since you're feeding the BFD directly then that's the reason.

I would advice to use your receiver/processor in the mix with REW and engage the crossover you will be using. You will accomplish far more with REW filtering and crossover interaction between the mains and sub that way.

In my opinion, whether your mains are big or not, using a 40Hz crossover has problems. You are allowing the bandwidth of your mains to extend into modal resonance areas where they can't be controlled. That's the entire reason for using a BFD equalizer in the first place. If you use the mains at a higher crossover (60Hz-80Hz), then the subwoofer takes care of the problem frequency range caused by the room. The subwoofer peaks can then be equalized.

Give a try to feeding your receiver/processor with REW and turn on a 60Hz crossover and show us a graph from (in your case with such a good sub) 10Hz-200Hz showing the 60Hz target. Sub only, no mains, stereo mode in your receiver with no soundfields.

brucek
 
#21 ·
Given your capable mains I would usually go with the 60 Hz (never 40Hz), but you do indeed have a peak at around 70hz likely caused by the floor to ceiling measurement of ~8 feet. If you use 60Hz as a crossover, the mains (which will suffer from the same resonance) might overwhelm the mix of the sub and main, and the peak might be tricky to get rid of. You could try it though at 60Hz and see how that goes.

If 60hz is a problem, then go with the 80Hz and see how that works out. I suspect it will be easier to get a smooth overall sub + mains when you're done using 80.

Man, your sub and room are some hot below 25Hz eh? Whew... The BFD will reduce that peak fine though...

Start off and eq the sub and then add the mains and try and match the level somewhat with the sub a bit hotter. Then play around with sub phase, sub receiver timing and filters to smooth the cross area (whichever one you choose 60 or 80)

brucek
 
#23 ·
I am guessing that you're displaying a full range graph of the mains and not crossed over mains?

I would suspect that the peak at 70 will probably be a bit additive. I'm thinking that 80Hz might be the best for you, but as I was saying before, you can try crossing at 60hz and see if you can keep the ~50-80 range looking good where the mains and sub are mixing. If not give 80 a try.

Make sure you eq your sub first by itself and then add in the mains and take a look..... Sometimes the mains will cause horrible results when added and you have to mess with the sub phase and filtering around the crossover to clean it up. Other times you simply might have to up the crossover and go to 80....

brucek
 
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