# Behringer FBQ2496 manual adjustment with RTA



## Andysu

Hello morning there. Okay I’ll cut straight the chase shall I?

I have an RTA analyzer a basic model that has range from 25Hz 40Hz 63Hz 100Hz 160Hz 250Hz 500Hz 1 KHz 2 KHz 4 KHz 8 KHz 16 KHz.

I’m using this with Behringer ECM8000 microphone and M100 preamplifier. 

Sub bass is an 18” JBL professional and the simplest of questions I’m looking for is…

What specific filter (bandwidth) should be used on the FBQ2496 that is described in figures on the display panel as shown?

Nothing much happens between when I use figures
1/60 1
1/60 2
1/60 2
1/60 3
1/60 4
1/60 5

That is until I get to these figures
0.10
0.11
0.12
0.14
0.16
0.20
0.25
0.33
0.50
0.75
1.0
1.5
2.5
3.0
4.0
5.0
6.0
7.0
8.0
10.0


I can hear the difference between the tone getting louder (which I assume is filter bandwidth) getting wider and then vice verse where the (bandwidth is getting narrower).

Also I’ve read the user’s manual:reading: over and over and over and over again and there is no reference as to what the shape of the filter looks like in relation to the bandwidth numbers? :scratch: 

Since there is no visual representation to show what the shape of the filter is, I’, wondering if anyone here knows that information as this would be huge benefit in getting the EQ done (manually) as apposed to (auto) with (computer software).

I’ll be standing by for a response as I would like to get this done today.

Thanks.


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## brucek

Just download REW for free and select the FBQ2496 equalizer (and the filter panel) and play with the filters to see their shape. (example below).

Or simply use REW to measure and do it all for you (including RTA duties).










brucek


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## Andysu

Whoa that was fast response thanks. 

So I don’t have to plug this into the BFQ2496, like you said just go to the page and tinker around with the settings, is that to help me, get a general idea on the shape of the filters bandwidth?

Again thanks.:T


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## Andysu

I’ve just looked up and down the link you provided but I’m afraid its amounts to a, needle in haystack, is what u have here, can you please provide direct link to specific article please.

Thanks.


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## Andysu

Well I’ve just gone ahead and installed Java and followed with Room EQ but when click on EQ and thou I haven’t made up lead as of yet with (smaller phone plug) to patch into the computer that would allow me to use ECM800 MIC100, I think I’ve (installed) the wrong, program as it says (DSP1124P) which is the first model they produced.

Or is there a button that selects between the two models DSP1124P and FBQ2496?

Thanks.


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## Andysu

Well I’ve patched up an already made lead (XLR to small phone plug) to the MIC100. I’ve played a sine wave sweep from (dts calibration and set-up disc) (track 14 sine wave sweep from 10Hz to 20 KHz) but stopping somewhere between the lower frequency register, I’ve noticed the gain meters are working on the Wizard which is good sign.

So how would I go about the simple task of recoding the (sine wave frequency sweep) for the sub bass only is there a recoding button?:scratch:

Thanks.


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## Andysu

Hmm, most interesting, most interesting, indeed. I like the way the Wizard can adjust the filter bandwidth) and no I haven’t been able to produce anything productive as yet and soon as I can figure this out with hands on time and I guess I’ll have to remain patient, until I’ve gotten more conference with rather fancy novel device, it’s funky.:yay:

I’ve sorted out the EQ under Equliser and selected the correct mode for the type of Behringer BFQ2496 that I’m using. So would it be just easier for me, to buy a lead to patch between the Behringer BFQ2496 a (MIDI) lead and if I’m not too mistaken I would need a little black box to patch between the (pc) to allow the MIDI lead to function between the Behringer BFQ2496. 

Thanks.


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## JohnM

Spending some time browsing the REW help files is highly recommended  either in the program itself or online

REW can program filter settings for you over Midi, as explained in the (you guessed it ) help files.


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## brucek

> Or is there a button that selects between the two models DSP1124P and FBQ2496?


Yes, the equalizer pull down allows you to select many types of equalizers (including the FBQ2496).

Here's an REW setup diagram for cabling and connections. Also reading the REW help files is recommended.

brucek


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## Andysu

Cheers for that links and online forum support, I’ll go though it.

Thanks.:T


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## Andysu

I’ve managed to get the connecting between using the (REW) Room EQ Wizard, and have conducted a few frequency sweeps has well as saving the, well Mr. REW does that for you, kinder like house butler, LOL. 

I guess you need to post up to ten posts or more before URL is allowed so, I’ll try and get up to ten or more then show three different frequency sweeps that I have done in the past hour.

Thanks.


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## Andysu

Okay I’ve sent print screen captures to (Photobucket) and hopefully the URL will now allow me to post my findings and I have no doubt you seen many like this before.

And by the way the weather is gorgeous over hare at the moment nice and warm, looks like the jolly ole British summer is now here.:yay:

Thanks.


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## Andysu

Test as done at 10 feet to the present listening area where the sofa is, ECM8000 was positioned behind and slightly over the back of the sofa, at ear height.

What I have done here is taken three frequency sweeps with (REW) Room EQ Wizard, the first one is with all three ports on JBL4645 18” sub as is.










Second frequency sweep is with one port hole plugged up, and as you can see there is mild difference between the, first frequency sweep.











Third frequency sweep is with two port holes plugged up, and as you can see again there is difference. 










So am I winning or not LOL.:dontknow:

Thanks.


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## Andysu

I’ve done a few more tests as well as a few guess works on the signal level calibration on the (FBQ2496). I took a reading with RTA my standard basic RTA and placed the ECM8000 1m away from the JBL sub and played some wideband pink noise from the dts calibration disc track 14 and slotted in a few filters where I saw the peak.

Filters used are 
25.1Hz
+2db
0.75

40.3Hz
-23db 
0.75

Now is this right is it wrong, it all seems to be trail and error and it kinder looks right to me, so far.

The first sweep wasn’t showing up to well, according to REW (Room EQ Wizard) and I forgot to add a little amplifier power, so I did a second frequency sweep test.

Thanks.

Final frequency sweep was with ECM8000 placed back at seating position.

First frequency sweep test









Second frequency sweep test


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## Andysu

Anyway since I’m mostly shooting in the dark, with a little (guessing here and there) I’ll fix the frequencies between just where 40Hz starts to drop off at and get a even line as possible up to around 120Hz which is where the LFE.1 starts to drop off at.

Again thanks for the forum support early this afternoon, this is a rather (beneficial device) and thou I would prefer a straight forward barograph display of the frequencies, you know the one with vertical straight lines, no matter I’m kinder getting use to the one REW Room EQ Wizard. 

Thanks.:T


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## brucek

Note:

The standard graph axis for vertical to use with REW is 45dB-105dB with a 75dB target.

The standard horizontal axis for a sub is from 15Hz to 200hz with a sweep from 0 to 200Hz. 

Using these axis will allow everyone to compare much easier.....

brucek


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## Andysu

brucek said:


> Note:
> 
> The standard graph axis for vertical to use with REW is 45dB-105dB with a 75dB target.
> 
> The standard horizontal axis for a sub is from 15Hz to 200hz with a sweep from 0 to 200Hz.
> 
> Using these axis will allow everyone to compare much easier.....
> 
> brucek


Hello there, I think I follow what you’re saying – so you’re saying I have two choices between how I should address the EQ with (REW). So where’s the horizontal and vertical button, as I’m still new to this device.

Thanks.


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## Andysu

One thing I’ve noticed is when conducting (sound check before frequency sweep) is that the sound check is never the same twice when repeating the test in the same position. That is the level is too low or it’s okay. Now is there a reason for this?

Thanks.


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## brucek

> So where’s the horizontal and vertical button, as I’m still new to this device


Graph Limits button icon in the top right corner. See REW HELP FILES



> so you’re saying I have two choices between how I should address the EQ with (REW).


I don't really understand your question. Those are vertical and horizontal graph axis values that are a standard.



> is that the sound check is never the same twice when repeating the test in the same position


It should be unless you've modified your setup, within a few dB.

brucek


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## Andysu

Unless of course I’ve assumed I’m looking at the correct field setting. So let’s assume I’m looking at the wrong field setting “graph” so what should it look like.

Also I should I set-up the “graph” felid settings. What should there vales be set at? 

Thanks.


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## brucek

> Unless of course I’ve assumed I’m looking at the correct field setting. So let’s assume I’m looking at the wrong field setting “graph” so what should it look like.
> 
> Also I should I set-up the “graph” felid settings. What should there vales be set at?


I'm afraid I don't really understand what you're asking. Sorry.

Can you rephrase it another way?

brucek


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## Andysu

brucek said:


> I'm afraid I don't really understand what you're asking. Sorry.
> 
> Can you rephrase it another way?
> 
> brucek


Okay, I think what I should have said is (Axis Limit Settings) what should the values be set at.
I’ve (print screen) to show how its set at present since the installation of (REW).

Thanks.


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## brucek

> I think what I should have said is (Axis Limit Settings) what should the values be set at.


For response measurements

Vertical axis = 45dB-105dB
Horizontal axis = 15Hz-200Hz

Target at 75dB

brucek


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## Andysu

Okay I’ve applied those settings to horizontal, vertical as is untouched. Now what’s next, should I perform the test again.

And by the way I have no crossover for the JBL 4645 has its running directly with LFE.1 only and since it only performs from (10Hz up to its cut-off point 120Hz) will this present a problem if I perform a frequency sweep from – lets say (20Hz to 120Hz}. In the ten years of owning the sub I haven’t had a single major issue with its performance.

Thanks.


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## brucek

> And by the way I have no crossover for the JBL 4645 has its running directly with LFE.1 only and since it only performs from (10Hz up to its cut-off point 120Hz) will this present a problem if I perform a frequency sweep from – lets say (20Hz to 120Hz}.


The sweep settings to test a subwoofer should be 0Hz-200Hz.

If you have the sub being fed from your receiver, then it would have the crossover set in the receiver (i.e. 80Hz). REW feeds the receiver AUX or CD input, and the receiver is set to stereo mode with the mains speakers disconnected. Then the sub only measurement can be carried out.

brucek


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## Andysu

I’ve done another frequency sweep test at 10feet distance to the listening position. Microphone is (point at the front) of the room. 

So what does those (level -19db ok) mean? I assume the level is correct or near to being correct as I have had ones that said (level is low).










Headroom I assume that means I have a good clear level before clipping and my amplifier Alesis RA300 is no where near clipping, unless I’m getting some false readings here? 










I’ve unplugged the ports and done the test over again. I would like to get this done right. But I having a little misdoubt with my conference with this device at the moment. Maybe you can delay me of these negative vibes I’m getting, or it could be that the, heat is getting to me, :gah::bigsmile: it’s rather warm today. 

Thanks.


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## brucek

> Maybe you can delay me of these negative vibes I’m getting


You'd have to answer these questions before I knew if you did things correctly.

Did you do a soundcard calibration routine and store the cal file in REW?

Did the measure a correct flatline response after doing the soundcard calibration of your loopback?

Did you download the microphone/meter calibration file for your mic/meter and store it in REW?

Did you do the Levels setup routine?

Did you calibrate the REW SPL meter?



> Headroom I assume that means I have a good clear level before clipping and my amplifier Alesis RA300 is no where near clipping


No, the clipping is in regard to the soundcard itself. Use the scope tab to observe the input/output levels if needed.

You should be placing the mic/meter in the upright vertical position at the listening position - not ten feet away.

brucek


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## Andysu

No I assumed the basic sound car in the pc was good enough. But if you feel strongly that I should make some calibration test then I’ll do so, just show me visual idea of what to look for please, as computers isn’t my strongest point.

Hmmm, microphone meter? I’m not sure if I did can you please provided direct link to (download file) please. 

(Microphone ECM8000 now placed in vertical position!) Ten feet away is the seating position.

I took another frequency sweep reading while adding a few more filters and have unplugged the ports, thou I feel, I should conduct a few of the above tests that you mentioned. Anyway mate, I’m off for walk down to the shop to get a can opener) being cocooned in the room all-day isn’t doing me any favours and I need to take a 1 hour break.

Thanks.


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## brucek

> No I assumed the basic sound car in the pc was good enough.


No, the basic soundcard is quite crummy actually and needs to have its rather inadequate response compensated for by doing a calibration and creating a file that corrects it's problems.



> Hmmm, microphone meter? I’m not sure if I did can you please provided direct link to (download file) please


Here is the link to the Download page

Your questions reveal that you perhaps haven't availed yourself of the knowledge that can be gained by simply reading THE REW HELP FILES. Please read these files before continuing.

brucek


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## Andysu

I’m back and they don’t even sale (can opener) imagine that.:no:

I’ll read though the link to help absorb enough information on the REW before struggling any further.

I’ll go to download page later on this evening after I have read several pages and then, continue onwards.

Thanks again for the online forum support, I’m sure I’ll get some productive results before the year is out.:rofl: 

Thanks.


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## thewire

Andysu said:


> One thing I’ve noticed is when conducting (sound check before frequency sweep) is that the sound check is never the same twice when repeating the test in the same position. That is the level is too low or it’s okay. Now is there a reason for this?
> 
> Thanks.


Your pink noise level for example when using the subwoofer level in the generator (in tools) or as when you setup the settings such as when doing the "check levels" there should = 75dB on your SPL meter and also 75dB in REW. Try lowering the wav volume then gradually (very slowly) adjust the level until your meter says 75dB. I have found it can take anywhere from 5 seconds up to 30 seconds to get this proper. Determining the proper sweep level can be indicated at the top of the bars during the check levels setup. Watch that each does not go red as this will cause clipping during the test proccess. Even better yet turn on the SPL meter in REW by pressing the red button and watch this reading costantly. During the setup proccess it will tell you if the sweep is appropriate because your reading at 75dB will not fluctuate. The different numbers bellow should be within 10dB from eachother. Then when you go to check levels watch again and if the SPL reading has not settled correctly to within at least .5 of your target (being 75dB for example 74.8 is acceptable IMO). Don't forget to calibrate the SPL meter when you begin to see it stabilize. If anything goes wrong, check your soundcard or try using different sweep levels with the generator again to see what is most stable and how smooth sounding the noise from the subwoofer has become.

Taking the time to verify the inputs accuracy and setup REW much slower than one might think to do so will result in my better testing over longer lengths of time as I have discovered spending almost full days doing so. Watching movies before testing helps also. I hope this makes since.


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## Andysu

Cheers for that brief input of information. I’ll switch everything ON later as I have just woke up too a headache, this late afternoon so I’ll get one with again later on.

Thanks.


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## Andysu

Hello evening guys. Well I think I’m starting to get some progress down here tonight. After take a few more tests and looking at the data on the REW room EQ Wizard I’ve managed to get a few smooth response from, 20Hz up to around 100Hz where I’ve gotten a bit of dip that’s giving me, headache as I’d like to get smooth roll-off down to 120Hz.

I’ll post the date before and after once I’ve finished the task.

Thanks.


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