# Equalization of TC-2000 sub.



## krisdz (Nov 11, 2007)

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


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## brucek (Apr 11, 2006)

> 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


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## krisdz (Nov 11, 2007)

[/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.


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## krisdz (Nov 11, 2007)

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


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## brucek (Apr 11, 2006)

> It make sense to you?


Yep, and that's what you'd expect for a standard commercial product. The +4dBu setting is usually reserved for pro products or high end processors that have a high output level.

With the trim at 0dB, and a loud movie, using -10dBV, you have a yellow LED and occasional RED - perfect..

brucek


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## krisdz (Nov 11, 2007)

Brucek
OK problem solved. Thx.
But it brings another question.
What will be the BFD output -10 dBv or + 4dBu?
It is neutral device so I will say – 10 dBv that mean to low for the EP-2500 which is Pro Amp.
Right or wrong?
Kris


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## brucek (Apr 11, 2006)

> 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


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## krisdz (Nov 11, 2007)

Brucek, 
Thanks for your help.
Do you want me to post here the measurements?
Kris


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## brucek (Apr 11, 2006)

Yep, that would be good......


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## krisdz (Nov 11, 2007)

The screenshot #1 is native no filters applied
The screenshot #2 is after couple of hours fight with BFD.
What you guys think? I’m going in to right direction?
Kris


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## brucek (Apr 11, 2006)

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


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## krisdz (Nov 11, 2007)

I started from scratch. Reset the BDF. Reload Room EQ.
Adjusted the graphs.
Measure without the filters. Then apply the 8 filters to BDF and is not much change between those two curves. 
I'm wonder if I'm doing something wrong? 
Kris


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## brucek (Apr 11, 2006)

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? 









brucek


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## krisdz (Nov 11, 2007)

Yeah, but I don't have much room to play with the sub. Do you want the jpg attached or posted?


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## brucek (Apr 11, 2006)

I would be interested in seeing a graph of the sub alone without the mains (including the target line set with the crossover you're using). 

brucek


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## krisdz (Nov 11, 2007)

All the graphs are the sub only and my crossover is set to 40 Hz. I have big mains.


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## krisdz (Nov 11, 2007)

I’m feeding the BFD directly from PC and RAW


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## krisdz (Nov 11, 2007)

Here are new graphs. I hope they look more promising. 
I did it wrong. I want use the sub up to 40-50 Hz why correcting frequencies above which I will never uses.


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## brucek (Apr 11, 2006)

> 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


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## krisdz (Nov 11, 2007)

Okay, I did what you ask for: Sub only, no mains, receiver in stereo mode with no sound fields.
1. X-over 40 Hz target 40 Hz
2. X-over 60 Hz target 60 Hz
3. X-over 80 Hz target 80 Hz
4. All together
Which one I shall use for the equalization?


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## brucek (Apr 11, 2006)

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


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## krisdz (Nov 11, 2007)

Thanks for the advice. 
I measured my mains only and compared them to earlier sub measurement.
Thy look kind of similar except of the bottom end gain.
What you think?


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## brucek (Apr 11, 2006)

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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## krisdz (Nov 11, 2007)

After I apply 5 filters it is still rough. I shall apply more filters over those five or play with those primary filters? What is the best practice?


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## brucek (Apr 11, 2006)

> What is the best practice?


Less is better. You really don't have to get it perfect. The goal is really to eliminate the main peaks caused by room resonance. Leave the dips alone. You've basically got three problem areas. Around 20Hz, around 35-40Hz and 70Hz.

brucek


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## krisdz (Nov 11, 2007)

After applying 12 filters in 3 rounds 5 then 4 then 3.
That what I get.
/quote Around 20Hz, around 35-40Hz and 70Hz / How you quote?
So 5-6 filters?


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## brucek (Apr 11, 2006)

> That what I get.


Not too good I'm afraid.

You need to put the target line up on your graph and make an attempt to average around that line. You can't drop from 20Hz as you've done.....

Set the crossover in REW and then set the target at 75dB. Be sure to press the Set Target Level once REW is calibrated to 75dB.

Follow the target.....

brucek


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## krisdz (Nov 11, 2007)

How that one look? 75db 60Hz sub only


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## brucek (Apr 11, 2006)

It looks a lot better. You do have enormous output below 20Hz, but the BFD can't do much about that and there's not a great amount of information below 20Hz. Movies with synthesized signal down that low will nicely shake your home.... You can chalk your rise to 14Hz a really aggressive house curve. 

Now you have to add your mains and see how well they integrate into that curve. Hopefully they'll come in around the 70-75dB range and not cause any new peaks or dips. If they do, you have phase, time and filters to work with....

BTW, what size enclosure is the TC-2K in?

brucek


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## krisdz (Nov 11, 2007)

The TC-2000 DVC is mounted in the 320l (Net) sonotube with both ends flared 6” 14.5 Hz port.
It was built on the base of many proven designs posted in DIY areas. (Thanks everybody and Home Theatre Shack). That means cap thickness, dumping materials, size etc. See attached pictures.
I still want use my mains lower end. To do so I need disconnect my woofers from the rest of the drivers in the box and put the BFD in between. I purchased my BFD for $50 on eBay. Maybe someday I’ll do so.
What you think?


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## brucek (Apr 11, 2006)

> I still want use my mains lower end. To do so I need disconnect my woofers from the rest of the drivers in the box and put the BFD in between.


The BFD is a line level device. The drivers in a speaker box are speaker level devices. They don't don't play well together..... sorry, that idea is non starter...... can't be done.

brucek


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## krisdz (Nov 11, 2007)

brucek said:


> The BFD is a line level device. The drivers in a speaker box are speaker level devices. They don't don't play well together..... sorry, that idea is non starter...... can't be done.
> 
> brucek


Yeah, stupid me! It’s Monday morning.
I need EP1500 + BFD to power my lower woofers in stereo mode right?
Then I’ll have nightmare to equalize there subs?
Do you have better solution in mind? Or my big mains are wasted or just expired.


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## brucek (Apr 11, 2006)

> I need EP1500 + BFD to power my lower woofers in stereo mode right?


Mmmm, well, the EP1500 is also a line level input device. What do you propose to drive it with? And if you were able, the EP1500's gain would have to match the gain of the receivers amplifiers......



> Do you have better solution in mind? Or my big mains are wasted


My solution is to set your mains to small in the receiver and leave it at that. They're not wasted, they still enter into the mix down to and below the crossover. 
My own mains retail at $11K, and I don't feel they're wasted by using them as small. The very bottom end of a woofer isn't what makes or breaks a good speaker........

brucek


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## krisdz (Nov 11, 2007)

I have two Bryston SST (Mono bridged) driving the mains. My pre/proc has ability to split the output.
So I will basically feed the EP1500 with the same signal which is going to Brystons. But let me try what you suggested. My mains cost “only” $5k twenty years ago and were one of the top at that time in Europe. Since there I replace all the caps and tweeters with new models.


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## brucek (Apr 11, 2006)

> I have two Bryston SST (Mono bridged) driving the mains. My pre/proc has ability to split the output.
> So I will basically feed the EP1500 with the same signal which is going to Brystons.


I use all Bryston amps too. Instead of the pristine signal that your Brystons supply, you're going to feed a BFD and EP1500 instead.............. shame on you..... :sad2:

brucek


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## krisdz (Nov 11, 2007)

After your comment I’m in deep depression. :hide: What I was thinking? LOL
Let me listen to it and then I’ll let you know what’s up.
Thank you very much for your time and the great support. 
Regards
Kris


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## krisdz (Nov 11, 2007)

Here it is as good as you get. (In my opinion after few hours of tweaking)
Sub and Mains together, stereo, no sound fields
Crossover @:
1. 40 Hz
2. 60 Hz
3. 80 Hz
4. 100 Hz
How it looks for you? 
It sounds marvellous. Very deep, long bass. I can’t find difference between 60 & 80 however 40 and 100 sounds not that deep. 
I used filter #12 as you suggested for the house curve and I still have 3 filters available.
We done here?


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## krisdz (Nov 11, 2007)

Brucek,
You were absolutely right! The interference from mains was obstructing the entire sound. I know that I was missing something but never have time to investigate.
Cutting the mains bottom and control it trough BFD was the key.
Even the room curves are still rough. The sound is now richer, deeper and panoramic.
I didn’t know that the frequency adjustment below 200 Hz is so important.
I guess, good mains can take care of them self above 200 Hz 
It is incredible how knowledge can help. I’m right now on completely different sound quality level.
Thank you again
Kris


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## brucek (Apr 11, 2006)

> We done here?


I think so. The 80Hz chart looks the best, but you'll have to choose which one suits you between 60Hz and 80Hz.

brucek


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## krisdz (Nov 11, 2007)

I was listening to all my fevered CD and DVD-A and it sound amazing now.
It is anything what I can do to improve it more? 
For example the BDF or EP2500 don’t have phase change.
How I can accomplish that?
Could you explain to me why the 80 look better then 60?
You think I’m annoying?


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## brucek (Apr 11, 2006)

> Could you explain to me why the 80 look better then 60?


Well, I think as we discussed, that the mains have less influence at your problem ~75Hz area if they are crossed at 80 rather than 60, and it shows that the peak at that point is lower and the mains appear to mix into the sub a bit better too.



> It is anything what I can do to improve it more?


I don't think so, others might. I'm not a fan of adding a mess of filters to try and get the response to absolutely track the target. You simply won't hear the difference. 



> For example the BDF or EP2500 don’t have phase change.
> How I can accomplish that?


Distance delay for the sub in the receiver is a very close approximation to a phase control. You can adjust it in and out if you think you need some phase change. I don't see anything that looks like phase problems though.

brucek


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## krisdz (Nov 11, 2007)

Hi Brucek,
Thanks again.
Regards
Kris


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