# House Curve question



## PoorSignal (Jul 23, 2009)

I read the posts but got really lost now!
are you supposed to tune everything flat first then add more filters to meet the target?

Also what happens to the response above crossover frequency, i.e. above 80hz, are you supposed to disconnect the main speakers. 

Would it be possible to do the tuning of PEQ with the main speaker on also, because it is very hard for me to reach back to unplug the speaker wires..

I attached a file of room response, I did some limited PEQ using my receiver. But what happens when I get the BFD, do I start with a new target line and then try to conform to it.


(crossover is at 80hz)

Thanks!


----------



## PoorSignal (Jul 23, 2009)

This is house curve I defined,

30 6.0
80 0.0

target set to full range, is the target line a right house curve?


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

PoorSignal said:


> I read the posts but got really lost now!
> are you supposed to tune everything flat first then add more filters to meet the target?


It’s usually best to use the filters to get the house curve.




> Also what happens to the response above crossover frequency, i.e. above 80hz, are you supposed to disconnect the main speakers.
> 
> Would it be possible to do the tuning of PEQ with the main speaker on also, because it is very hard for me to reach back to unplug the speaker wires..


No, you have to get a subs-only reading. If not, REW will try to equalize that graph as if it’s a sub. Check this thread to see what will happen if you try that. Doesn't your receiver have a switch or something to turn off the L/R speakers?




> But what happens when I get the BFD, do I start with a new target line and then try to conform to it.


You’ll start from scratch once you get the BFD.




> This is house curve I defined,
> 
> 30 6.0
> 80 0.0
> ...


If your room needs a 6 dB house curve, then yes that’s correct. However, it looks like you have your Target curve set for full range, not subwoofers.

Regards,
Wayne


----------



## PoorSignal (Jul 23, 2009)

When trying to follow a house curve is it normal for the response to swing up and down along the target? This is due to filters right? 

Can you explain how to best apply the filters to make it conform, just experiment so that it uses the least filters?

I already tuned my phase correct with the mains. What happens when I got it to match the target, connect the mains again and the integration causes more dips, do you go back and fix it?

When everything is finished do you fine tune the receiver volume level so that volume at 30hz is about 6db greater than that at 120hz (mains)


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

> When trying to follow a house curve is it normal for the response to swing up and down along the target? This is due to filters right?


Not the filters so much. Often response is up and down because of what the room does to it. It’s virtually never perfectly flat. But basically, the house curve should track the Target. Here’s an example.







​



> Can you explain how to best apply the filters to make it conform, just experiment so that it uses the least filters?


If you align the Target curve properly with your response, REW can do a good job of filtering. Or, you can experiment and create your own filters, or modify what REW recommends You can do it all on-screen; REW will show the predicted response. 



> I already tuned my phase correct with the mains. What happens when I got it to match the target, connect the mains again and the integration causes more dips, do you go back and fix it?


A parametric equalizer can often take care of problems that appear once the mains are added to the sub.




> When everything is finished do you fine tune the receiver volume level so that volume at 30hz is about 6db greater than that at 120hz (mains)


No, the exercise to determine the difference between the 30 Hz and 120 Hz test tones is done first. That determines if your house curve needs to be 4, 5, 6, or whatever dB.

Regards,
Wayne


----------



## PoorSignal (Jul 23, 2009)

My last question meant, how do you adjust the subwoofer channel volume in the receiver vs the L,R,Center etc.

L,R,C set to same volume test tone via SPL checking.

Do you do this last?


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

After equalizing the sub, you set your sub level as you would normally, using the receiver's test tones or a calibration disc. After that, it's not a bad idea to go through some material to see if the sub level needs further tweaking. The sub level should sound "right" to you - not weak or overbearing.

Regards,
Wayne


----------



## PoorSignal (Jul 23, 2009)

I added house.txt

30 6.0
80 0.0

Can you tell me why there is about 10db difference between 30 and 80 hz..
if I set the curve to full range the it is OK

it has to do with the subwoofer cut off, if my receiver cross over is 80hz then should I put 80 in that field?


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

> Can you tell me why there is about 10db difference between 30 and 80 hz..
> if I set the curve to full range the it is OK


Not sure what you’re using as your reference points, but the house curve merely adds so-many dB to the Target Curve (6 dB in your case). The Target Curve tracks the crossover slope you’ve selected for your subwoofer (24 dB/octave in your case).




> it has to do with the subwoofer cut off, if my receiver cross over is 80hz then should I put 80 in that field?


Yup, that’s correct.

Regards,
Wayne


----------



## PoorSignal (Jul 23, 2009)

So the target curve is correct if I want 6db difference between 30 and 80hz,
even though the actual difference if I meet the target is more like 14db, according to the target graph.


----------



## JohnM (Apr 11, 2006)

PoorSignal said:


> So the target curve is correct if I want 6db difference between 30 and 80hz,
> even though the actual difference if I meet the target is more like 14db, according to the target graph.


It is not 6dB difference, it is 6dB more at 30Hz than it would be without the house curve (and 0dB more at 80Hz).


----------



## PoorSignal (Jul 23, 2009)

JohnM said:


> It is not 6dB difference, it is 6dB more at 30Hz than it would be without the house curve (and 0dB more at 80Hz).


Arh!! It makes sense now.
The original curve that REW puts in there is just a standard 80hz crossover for the sub to fade out around 80hz right?


----------



## JohnM (Apr 11, 2006)

Yep, you got it.


----------



## PoorSignal (Jul 23, 2009)

Wayne A. Pflughaupt said:


> Not the filters so much. Often response is up and down because of what the room does to it. It’s virtually never perfectly flat. But basically, the house curve should track the Target. Here’s an example.
> 
> 
> View attachment 19643​




How can I get the straight line like yours? Do you have to put more linear samples in the house curve file?

Well, I found the one posted by Wayne, it looks like you have to fudge the values until it is straight, but I have a hard time converting that to 80hz cut off, or coming up with my own, it's too hard. Any tips?


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

The Target Curve, with or without a house curve added, is mere a target line for the subwoofer qualization to generally track. After equalization, the sub level needs to be re-adjusted to blend properly with the mains. Once that happens, the "actual difference" will probably not be anything near 14 dB.

Regards
Wayne


----------



## PoorSignal (Jul 23, 2009)

This is the 80hz version I have came up with. Is it straight enough? I am overly obsessed with little numbers in real life! But I can see the little jags if I change the scale more, kept using a straight edge on the screen to check.

30 6.5
35 4.8
40 3.3
45 2.1
50 1.2
55 0.5
60 0.0
65 -0.25
72 -0.3
76 -0.2
80 0.0


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

Looks good. :T

Regards,
Wayne


----------



## JohnM (Apr 11, 2006)

PoorSignal said:


> How can I get the straight line like yours?


On the house curve settings page tick the "use logarithmic interpolation" box.


----------

