# Response graph



## Guest (Oct 30, 2006)

Hello everybody.

I have just bought a Behringer 1124 and have almost read the article about this equalizer. I have a SVS PB10 subwoofer and Dali Ikon 6 speakers. I have an old Yamaha 595 receiver. My fronts are set to small and bass is set to sub only.

I have tried to measure the response from the specific frequencies. Here is the graph:
http://img130.imageshack.us/img130/3...board01bk9.jpg

This is without Behringer etc. Just measured in my room. I will try to make a new graph where the futon bed is turned into a sofa etc. so my things in the room is as it is when I watch movies and so on. I think that it might have an effect whether the futon is a sofa or a bed and so on. 

Look at the brown one (the white was my old subwoofer). As you can see the response from 30-31Hz and above is pretty much higher than <30Hz. I have read in the article that you should only use the subwoofer when measuring. Why is that? Because when I turned of the subwoofer my fronts also played the bass-frequencies. I think I could measure it from app. 30Hz and above and it got louder the higher frequency I tried. I have been told that this is how the receivers do. Then, why should I turn off the fronts? The I don't get the correct curve because my fronts plays as well but this is just not measured if you only use the subwoofer.

How can I get the best result? Is it to lower the sound level from 30Hz and above to the level at 20-25Hz? 

Thank you very much in advance.

Best regards,
Martin


----------



## Otto (May 18, 2006)

Hi Martin,

In general, since we want to process the sub signal with the BFD, we only want to consider its response during the measurements. If you also throw in the main's contribution to the signal, then REW (or the user) may try to create filters that won't really apply to what you're trying to do. 

Once your sub is equalized to your liking -- whatever curve sounds good to you -- you can set the levels between your sub and you mains, as well as play around with crossover settings and frequencies, etc.

Good luck and have fun!


----------



## brucek (Apr 11, 2006)

> Here is the graph:


Bad link..........:no: 



> I have read in the article that you should only use the subwoofer when measuring. Why is that?


We want to see the sub without any other speakers influence affecting it, especially around the crossover frequency (i.e. 80Hz), where both mains and sub are producing like frequencies. Since the sub is the only speaker we are equalizing, we do that first.

The crossover in the receiver isn't a brick wall. The mains and sub gradually lower their outputs from the crossover frequency. First we equalize the sub alone, then when that is finished we add the mains to see the effect they have on the overall response. It's at this point we adjust the subs phase control to get the smoothest response. Then we may tweak a few filters to further smooth the response.



> How can I get the best result? Is it to lower the sound level from 30Hz and above to the level at 20-25Hz?


If the sub is in the best position in the room for the lowest response possible (usually a corner), then trying to get more out of a subs bottom end when it isn't designed for it, isn't usually too successful. If the sub is designed to go down to 20Hz and the 30Hz area is higher because of a room resonance, then reducing 30Hz will be quite successful.

brucek


----------



## Guest (Oct 30, 2006)

brucek said:


> Bad link..........:no:
> 
> 
> We want to see the sub without any other speakers influence affecting it, especially around the crossover frequency (i.e. 80Hz), where both mains and sub are producing like frequencies. Since the sub is the only speaker we are equalizing, we do that first.
> ...


First of all, Thank you Otto and Brucek.

Here is a fixed link:
http://peecee.dk/?id=9807

The sub is placed in a corner just beside my sofa. It is turned 180 degrees compared to the front speakers. Here is a few pictures.

Sub:
http://peecee.dk/?id=9809

Other side (front and old sub)
http://peecee.dk/?id=9811

I have to go to work now so I can't reply before tomorrow. 

Thank you anyway. I would be very glad if you could tell me what to do. Which curve should I try to get? An almost horisontal line when the receiver is set to stereo?


----------



## brucek (Apr 11, 2006)

> Other side (front and old sub)


Hopefully, you're not trying to use the old sub with the new SVS? This is a mistake that would 'dumb down' the SVS to the response of the old sub...



> Which curve should I try to get? An almost horisontal line when the receiver is set to stereo?


The sub is usually an equal amplitude at the crossover and then slowly ramps up about 5dB to 30Hz and then flattens as it reaches 20Hz. That's a perfect world.

You've modified the excel graphs vertical and horizontal axis. I would revert back to a vertical scale of 45dB to 105dB. It is not necessary to extend to 12Hz on the horizontal scale. I would revert back to 16hz to 200Hz.

brucek


----------



## Guest (Oct 31, 2006)

brucek said:


> Hopefully, you're not trying to use the old sub with the new SVS? This is a mistake that would 'dumb down' the SVS to the response of the old sub...


Definately not :neener:. I just forgot to erase it when I uploaded the image.



brucek said:


> The sub is usually an equal amplitude at the crossover and then slowly ramps up about 5dB to 30Hz and then flattens as it reaches 20Hz. That's a perfect world.
> 
> You've modified the excel graphs vertical and horizontal axis. I would revert back to a vertical scale of 45dB to 105dB. It is not necessary to extend to 12Hz on the horizontal scale. I would revert back to 16hz to 200Hz.
> 
> brucek


I haven't done anything. I have used the graph from Lsound. Here is the new one downloaded from this site:
http://peecee.dk/?id=9876

THIS WORKSHEET IS USED WITH THE NEW RS ANALOG METER MODEL #33-4050 

The pink line...is this the optimal graph? Or should it be more flatten before 30Hz.


----------



## brucek (Apr 11, 2006)

> The pink line...is this the optimal graph? Or should it be more flatten before 30Hz.


The pink line corresponds to the entries you made in the table labelled "RAW SPL BFD". This is the list of raw responses you get from your RS meter after you've entered your filters into the BFD equalizer.

The blue line corresponds to the entries made in the table labelled "RAW SPL". This is the list of raw responses you get from your RS meter before you enter any filters in your BFD.

In this way you can see the before and after responses on the same graph....

brucek

edit:



> I haven't done anything. I have used the graph from Lsound


Sorry, the graph looked so much like ours, I thought you used it with modifications. I think using the one from HomeTheaterShack site provides more accurate compensation values for the specific meter you're using.


----------



## Guest (Oct 31, 2006)

brucek said:


> The pink line corresponds to the entries you made in the table labelled "RAW SPL BFD". This is the list of raw responses you get from your RS meter after you've entered your filters into the BFD equalizer.
> 
> The blue line corresponds to the entries made in the table labelled "RAW SPL". This is the list of raw responses you get from your RS meter before you enter any filters in your BFD.
> 
> ...


Yes okay. I understand that now. Are you talking about the house curve when you say "The sub is usually an equal amplitude at the crossover and then slowly ramps up about 5dB to 30Hz and then flattens as it reaches 20Hz. That's a perfect world."

Because when you listen to music then it would be better to have a horisontal curve? I use it for both music and movies. I have found out that my receiver makes it to the house curve when I select surround-mode so what I have to do is to make an almost horisontal graph for music right? Then the receiver would make it to a house curve if I watch movies. 

Thank you for your help.




brucek said:


> edit:
> 
> 
> Sorry, the graph looked so much like ours, I thought you used it with modifications. I think using the one from HomeTheaterShack site provides more accurate compensation values for the specific meter you're using.


No problem. I use the one from this site now .


I have just taken a couple of new images:

Front:
http://peecee.dk/?id=9882

Back (far away)
http://peecee.dk/?id=9880

Back (close)
http://peecee.dk/?id=9881


----------



## brucek (Apr 11, 2006)

> Are you talking about the house curve when you say "The sub is usually an equal amplitude at the crossover and then slowly ramps up about 5dB to 30Hz and then flattens as it reaches 20Hz. That's a perfect world."


Yes.....



> Because when you listen to music then it would be better to have a horisontal curve? I use it for both music and movies.


Well, many of us use two programs in the BFD. We have one for music, that is fairly flat as you correctly indicate and one for movies that boosts the bottom end somewhat. It's really just a matter of what sounds good to you.

The important issue is to reduce the peaks that are caused by room resonances. Then listen for a while and see if you like it. Then you can mess with a house curve.

Here's the area to work on with the BFD. Once that is reduced you'll find you may have to turn up the SVS amplifier a bit to compensate, because before filtering, it was that area in red that you were mostly listening to and it determined your sub level..... Once you remove the area in red you'll begin to hear the very low frequencies better... Make sense?










brucek


----------



## Guest (Oct 31, 2006)

brucek said:


> Yes.....
> 
> 
> Well, many of us use two programs in the BFD. We have one for music, that is fairly flat as you correctly indicate and one for movies that boosts the bottom end somewhat. It's really just a matter of what sounds good to you.
> ...


As I tried to explain:
I use the subwoofer for both music and movies. I have found out that my receiver makes it to the house curve when I select surround-mode so what I have to do is to make an almost horisontal graph for music right? Then the receiver would make it to a house curve if I watch movies.

My father has an oscilloscope and we wanted to make sure that the testtones was playing with the same amplitude all the way from 16-160Hz. It was set to surround-mode and I couldn't understand why the amplitude got lower at around 31,5Hz and it then continued to fall when I played frequencies above 31,5Hz. Then I pressed the stereo-mode and measured again. Then the amplitude was the same though all the frequencies. 

So what I need to do:

1. Select stereo-mode.
2. Only use the sub without any other speaker.
3. Try to get a flat curve (because when playing movies it will turn into a house curve itself). 
4. Connect the front speakers. Then re-adjust (fine) so the curve will turn into a flat curve again because it might have changed a bit.

Is that correct?



brucek said:


> Here's the area to work on with the BFD. Once that is reduced you'll find you may have to turn up the SVS amplifier a bit to compensate, because before filtering, it was that area in red that you were mostly listening to and it determined your sub level..... Once you remove the area in red you'll begin to hear the very low frequencies better... Make sense?
> 
> brucek


Yes it absolutely makes sense. I will try to reduce this area with the Behringer.

Thank you very much for your help. It is much appreciated :clap: .


----------



## brucek (Apr 11, 2006)

> My father has an oscilloscope and we wanted to make sure that the testtones was playing with the same amplitude all the way from 16-160Hz. It was set to surround-mode and I couldn't understand why the amplitude got lower at around 31,5Hz and it then continued to fall when I played frequencies above 31,5Hz. Then I pressed the stereo-mode and measured again. Then the amplitude was the same though all the frequencies.


But if your receiver employs standard bass management, irregardless of the mode, if the mains speakers are selected as small (and they should be), then you will not have the same amplitude all the way from 16-160Hz. The crossover setting in the receiver (i.e. 80Hz) slowly reduces the output to the sub as the frequency increases and also slowly reduces the output to the mains as the frequency decreases. This is standard bass management.

The output to the sub should therefore adhere to a target of the following picture if you select a 80Hz crossover:









The output to the mains would adhere to a target of the following picture if you select a 80Hz crossover:









When the responses of both main and sub are mixed together in the room they then create a fairly horizontal flat response. If we didn't use this type of bass management and ran mains or sub full range, then the common frequencies would re-inforce and cause a hump. We don't want this. It is not what we are referring to as a house curve.

A house curve is applied to the subs response by boosting the lower frequencies to result in a target like the following: This target adds 5dB extra from 80Hz down to 30Hz on top of the normal target.










Ensure that in all modes in your receiver, that you have your speakers set to small and not large (which defeats bass management for that speaker).....

brucek


----------



## Guest (Oct 31, 2006)

brucek said:


> But if your receiver employs standard bass management, irregardless of the mode, if the mains speakers are selected as small (and they should be), then you will not have the same amplitude all the way from 16-160Hz. The crossover setting in the receiver (i.e. 80Hz) slowly reduces the output to the sub as the frequency increases and also slowly reduces the output to the mains as the frequency decreases. This is standard bass management.


The front speakers are set to small in all modes. The oscilloscope was connected to the subcable (the sub was not connected because we measured the output from the receiver) and in stereo-mode it was flat while in surround-mode it was a house curve. 
I can't set the crossover. It is done by the receiver (a pretty old one) so I can only set the speakers to small/large and bass to sub, main og both. The crossover might be 80Hz but I don't know for sure.



brucek said:


> A house curve is applied to the subs response by boosting the lower frequencies to result in a target like the following: This target adds 5dB extra from 80Hz down to 30Hz on top of the normal target.
> 
> View attachment 1066


Don't you mean app. 60Hz? There is more than 5db between 80Hz and 30Hz. 




brucek said:


> Ensure that in all modes in your receiver, that you have your speakers set to small and not large (which defeats bass management for that speaker).....
> 
> brucek


It is done .


----------



## brucek (Apr 11, 2006)

> Don't you mean app. 60Hz? There is more than 5db between 80Hz and 30Hz.


Nope, I mean 80Hz. Below is a standard bass management target with an 80Hz crossover overlayed with the same target with a housecurve that rises slowly from the crossover at 80Hz down to 30Hz. At 30Hz and below, the target is 5dB greater..... 











> The front speakers are set to small in all modes. The oscilloscope was connected to the subcable (the sub was not connected because we measured the output from the receiver) and in stereo-mode it was flat while in surround-mode it was a house curve.


OK, you have a receiver that has the attribute where they consider stereo aficionados will not want any management applied to the mains. Actually this feature is often applied to very expensive processors when they are placed in bypass mode. 

Usually when this is the case, then there is no subwoofer signal output. You have a receiver where they are also outputting a full range sub signal. (interesting that you have this feature. My processor also works this way in bypass mode. It's a Bryston SP2). 

This creates a situation where only in stereo bypass you need to apply external bass management to the sub signal and set it for a crossover very low, since your mains will also be outputting a full range signal. The usual fix for this (at least the way I do it), is to use the subwoofers own internal low pass filter as a crossover set very low ~50Hz. Then when listening to multi-channel, you dial the subs own crossover up high out of the way and let the receiver do the bass management.

Another way would be to use two BFD programs. The stereo one would be acting as a crossover plus filters for the sub, and the multi-channel HT one would be just simple filters.

brucek


----------



## Guest (Oct 31, 2006)

brucek said:


> Nope, I mean 80Hz. Below is a standard bass management target with an 80Hz crossover overlayed with the same target with a housecurve that rises slowly from the crossover at 80Hz down to 30Hz. At 30Hz and below, the target is 5dB greater.....


Ohh I see.



brucek said:


> OK, you have a receiver that has the attribute where they consider stereo aficionados will not want any management applied to the mains. Actually this feature is often applied to very expensive processors when they are placed in bypass mode.


Hmm, mine isn't a very expensive receiver as far as I know. I have found the manual:
http://media-server.amazon.com/exec...iBNYW51YWw=&file=TUFOVUFMMDAwMDMyMjUyLnBkZg==
It is just a version called RX-V595-aRDS but I don't think it matters.




brucek said:


> Usually when this is the case, then there is no subwoofer signal output. You have a receiver where they are also outputting a full range sub signal. (interesting that you have this feature. My processor also works this way in bypass mode. It's a Bryston SP2).


On page 13 you can see that there is a subwoofer output if this is what you think there isn't. 



brucek said:


> This creates a situation where only in stereo bypass you need to apply external bass management to the sub signal and set it for a crossover very low, since your mains will also be outputting a full range signal. The usual fix for this (at least the way I do it), is to use the subwoofers own internal low pass filter as a crossover set very low ~50Hz. Then when listening to multi-channel, you dial the subs own crossover up high out of the way and let the receiver do the bass management.


Can I do that? My PB10 only has phase and gain. 



brucek said:


> Another way would be to use two BFD programs. The stereo one would be acting as a crossover plus filters for the sub, and the multi-channel HT one would be just simple filters.
> brucek


I am not sure of that one...

Maybe I will buy a Harman Kardon 4xx/6xx later. Do you know if it will act different? Doesn't these receivers have a house curve for movies like mine have now?


----------



## brucek (Apr 11, 2006)

> I have found the manual:


I looked at the manual and there is no indication that in stereo mode that the crossover to the sub is bypassed, so I have no idea why you're experiencing the situation in stereo where the signals at lower sub frequencies being as strong as the signals at higher sub frequencies.....



> Can I do that? My PB10 only has phase and gain


Nope, if it doesn't have a low pass filter adjust on it, then you can't do that. You would have to use BFD filters to do this.



> Doesn't these receivers have a house curve for movies like mine have now?


Well, as we discussed before, your receiver and all other receiver do not have a house curve. House curves are a result of boost provided by external equalizers like a BFD on subwoofer signals.

brucek


----------



## Guest (Oct 31, 2006)

brucek said:


> I looked at the manual and there is no indication that in stereo mode that the crossover to the sub is bypassed, so I have no idea why you're experiencing the situation in stereo where the signals at lower sub frequencies being as strong as the signals at higher sub frequencies.....
> 
> 
> Nope, if it doesn't have a low pass filter adjust on it, then you can't do that. You would have to use BFD filters to do this.


Okay. I don't know why too then. This is just what we measured. Anyway, I then need to create two filters, one for movies and one for music. Which filter number is best to use? It think I read that filter number 10 is the one it starts with if the Behringer is completely turned off (don't know what it is called ). 



brucek said:


> Well, as we discussed before, your receiver and all other receiver do not have a house curve. House curves are a result of boost provided by external equalizers like a BFD on subwoofer signals.
> brucek


I didn't realize that. I thought that the receiver itself could make this house curve if it was designed for it (an internal equalizer). 

Bypass, what does it exactly?


So what I need to do:

1. Select stereo-mode.
2. Only use the sub without any other speaker.
3. Try to get a flat curve (in filter number 10 if this is the one I uses the most).
4. Connect the front speakers. Then re-adjust (fine) so the curve will turn into a flat curve again because it might have changed a bit.

Then for movies:
1. Select surround-mode.
2. Only use the sub without any other speaker.
3. Try to get a house curve (in filter number 9?).
4. Connect the front speakers. Then re-adjust (fine) so the curve will turn into a house curve again because it might have changed a bit.

Is that correct?

Thank you.


----------



## brucek (Apr 11, 2006)

> Which filter number is best to use?


You can use any program from 1 to 10, but many use 4 or 5 because all the 12 filters of each of those programs are set for parametric mode.
The BFD starts in the default program the very first time it's turned on. After that it turns on in the last program that was selected.



> Bypass, what does it exactly?


Bypass is a word used for a stereo mode many receivers and processors use to strip as many bells and whistles away and leave pure unaffected stereo signal. It's a misnomer because there are varying degrees of bypass provided.



> Is that correct?


Pretty much, except the sub only target is as I showed in the pictures except you'll have 90Hz crossover that is fixed in your receiver in the movie mode.
In the stereo mode, (if there is no crossover invoked as you have measured), then you will need to create filters to produce a close resemblance to the crossover target.

brucek


----------



## Guest (Nov 1, 2006)

brucek said:


> You can use any program from 1 to 10, but many use 4 or 5 because all the 12 filters of each of those programs are set for parametric mode.
> The BFD starts in the default program the very first time it's turned on. After that it turns on in the last program that was selected.


Okay. I just found why I asked: "Here's a tip from Gary Kratochvil: For those out there who use a remote to turn on/off the power to the BFD... set up the BFD so that your favorite filters are stored in preset 10. Preset 10 is the default preset where the BFD returns to after losing power." But it only seems to be an issue if you use a remote control.



brucek said:


> Bypass is a word used for a stereo mode many receivers and processors use to strip as many bells and whistles away and leave pure unaffected stereo signal. It's a misnomer because there are varying degrees of bypass provided.


Sounds a bit too complicated to me :coocoo:. 



brucek said:


> Pretty much, except the sub only target is as I showed in the pictures except you'll have 90Hz crossover that is fixed in your receiver in the movie mode.
> In the stereo mode, (if there is no crossover invoked as you have measured), then you will need to create filters to produce a close resemblance to the crossover target.
> 
> brucek


Dammit. I don't understand that. Sorry :duh:
Could you please try to explain it in another way? Thanks...


----------



## brucek (Apr 11, 2006)

> I don't understand that. Sorry


I'll try again.

You have indicated that in stereo mode your subwoofer output is not passed through a crossover in your receiver and as such signals at 50Hz would be at the same level as 160Hz. If this is indeed the case, then you need to provide an external crossover for that sub signal. You don't have a crossover in your sub, so the only alternative would be to create a pseudo-crossover in your BFD with filters. 

On top of this crossover duty in the BFD, you'll need to do some standard equalization of the sub signal to reduce peaks caused by the room resonances.

A response target to shoot for in this situation would be as shown below for a crossover of 90Hz.









In the surround mode you indicate that the crossover is working, so the only work you'll have to do with the BFD is to filter out any peaks. The target to shoot for will still be the same as the plot above, but it should be easier than the program you created for stereo mode...

For now I would forget about house curves and work on achieving the target response as shown in graph.


brucek


----------



## Guest (Nov 2, 2006)

brucek said:


> I'll try again.
> 
> You have indicated that in stereo mode your subwoofer output is not passed through a crossover in your receiver and as such signals at 50Hz would be at the same level as 160Hz. If this is indeed the case, then you need to provide an external crossover for that sub signal. You don't have a crossover in your sub, so the only alternative would be to create a pseudo-crossover in your BFD with filters.
> 
> ...


Thank you. I think that I understand it now . Yesterday I measured again - both stereo- and surround-mode. Here is the result:
http://peecee.dk/?id=10172

The blue is stereo and the pink one is surround. It doesn't seem like the before-measured values, does it? 
To app. 60Hz it seems to be exactly the same but afterwards it varies a bit. This might change the situation, right?

Thank you for your reply :bigsmile:


----------



## brucek (Apr 11, 2006)

> It doesn't seem like the before-measured values, does it?


No, it appears closer to what I would expect. The stereo and HT mode are quite similar.

So, try and use the BFD filters to bring down the hump to the red line as I've shown below. When you're done, you may find that you have to increase the subwoofer amplifier level because you've been listening to that hump. Reduce the hump with filters, turn up the sub a bit and you'll be good.









brucek


----------



## Guest (Nov 2, 2006)

brucek said:


> No, it appears closer to what I would expect. The stereo and HT mode are quite similar.
> 
> So, try and use the BFD filters to bring down the hump to the red line as I've shown below. When you're done, you may find that you have to increase the subwoofer amplifier level because you've been listening to that hump. Reduce the hump with filters, turn up the sub a bit and you'll be good.
> 
> brucek


Excellent. Just for fun and to see how it reacted I tried to reduce the area from 35-80Hz with 14db and the hump was almost gone. Well, there is still a 10db gap from the highest to the lowest value but I found out that I need to turn up the volume on the sub.

Thank you very much for your help so far. Maybe I will have some questions later but I will definately try what you showed on the last graph. 

Have a nice day! :T


----------



## Guest (Nov 3, 2006)

Ohh...I forgot one thing. The graph above, isn't that only for music? Then for movies the area from 20-30Hz need to be app. 5db louder? Or will the bass be too weak from 30-XXHz? Because then you need to reduce the area from 30-XXHz pretty much. 
What would you recommend?
Thank you.


----------



## brucek (Apr 11, 2006)

> The graph above, isn't that only for music?


Yeah, I think it's usually best when someone first equalizes a sub, to listen for a while to get used to the sound. Then if they think the bottom end is lacking a bit it would be time to add a house curve. They might even want that for music. I would try the flat response for a while and see what you think.

brucek


----------

