# Interpreting my graph PLS



## Masterolli (Sep 28, 2010)

hi,
ihave measured my sub , but what i get... i think its quite bad.
Problem is i dont have much positions for the sub.
i have a DSP1124, maybe i can correct as much as possible?
Or what would be the thirst thing i have to do?

I dont have an spl meter only an ecm8000 i dont know what the reference level is to get 75db. 

thank you


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

Welcome to the Forum Mastrolli!

I’m not used to seeing such a steep drop above 40 Hz. What is the crossover frequency you are using for your subwoofer?

Regards,
Wayne


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## Masterolli (Sep 28, 2010)

hi,
Im using 80hz for crossover.

What can i do?


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

Since you can’t relocate the sub, your options are limited. That response is too bad to completely flatten out with an equalizer. Since you don’t have a SPL meter don’t worry about the 75 dB reference level. 

You can use REW’s RTA feature and adjust the filters on the BFD in real time – i.e., you’ll be able to see the change in response on the screen. This thread tells about the RTA feature.

I’d suggest cutting the peaks at 20 and 40 Hz down. However, reducing them by about 10 dB is the best you’ll probably be able to do. As I mentioned, you won’t be able to get flat response, but you can at least make an improvement.

Regards,
Wayne


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## Masterolli (Sep 28, 2010)

ok thank you i will try your advice... when I have tried all out I will post my results.
Here u can take a look at my Room, can u say something to it, maybe u got an better eye for it.
Personally, I found no other option to set up my 5.1 System.


grettings olli


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

Yeah, that’s a tough room! You might try moving the sub over to where the front right speaker is. With the door closed it would be near a “decent” corner – against one room boundary and close to another. That would probably be better than it is now. The present sub location is essentially out in the middle of the floor – hardly ever a good option.

If all else fails you could try putting at the left rear speaker. I’m not fond of rear subs, but that might be better than having bad response.

Regards,
Wayne


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## Masterolli (Sep 28, 2010)

hi,
where the Left Rear Speaker is, that would not be an option, because otherwise it would not be possible to get on the terrace, thats bad.
near the right front speaker would be possible, but does it plays a role when the subwoofer direction would look to the Right Front or Left Front Speaker?
Because the sub is very big and when i will place it with direction to listening pos near the right front speaker, there would be small place to passthrough table and sub.

greetings olli


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## lsiberian (Mar 24, 2009)

Masterolli said:


> hi,
> where the Left Rear Speaker is, that would not be an option, because otherwise it would not be possible to get on the terrace, thats bad.
> near the right front speaker would be possible, but does it plays a role when the subwoofer direction would look to the Right Front or Left Front Speaker?
> Because the sub is very big and when i will place it with direction to listening pos near the right front speaker, there would be small place to passthrough table and sub.
> ...


At the very least I'd pull it out of the smaller room section. It also looks like you have the volume too high for REW on the measurements. Take it down so we can get a better idea.


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## Masterolli (Sep 28, 2010)

hi,
have tested now several possible positions, what du u mean to my result?
I have turned the volume of my av receiver a little bit down.

the graphs are from number 1 to 4 down.

pos 3 is beside the table and pos 4 under the table.
The redline is the direction of the speaker.

I think the new pos are better then the old pos.

Which one should i now use?

I am living alone in my apartment, so every pos wolud be possible, but i would prefer pos 1 and 2 for the WAF better saying my acception factor, dont know anyone who has his sub beside his table or under.
But when pos 3 and 4 u say is xxx times better then the others...


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

Unfortunately those locations are getting even worse results. What about that corner behind the front left speaker? Can you try that location?

Regards,
Wayne


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## Masterolli (Sep 28, 2010)

hi,
here is the graph for the pos, behind the front left speaker, the sub has 30cm space to the back and to the left wall and direction to listening pos.

Im really glad, that this is such a nice forum and the people are so helpfully 
greetings olli


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## Masterolli (Sep 28, 2010)

sorry forgot smoothing


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## Masterolli (Sep 28, 2010)

and this one i could get out by playing with the corner


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

Actually, taking another look at your graphs in Post #9, the red and green graphs at least show you’re getting the upper bass in the equation. It would be easier to tell if you posted the graphs with a horizontal axis of 10-200 Hz and vertical axis of 45-105 dB – see here. Sorry for not noticing earlier. 

Regards,
Wayne


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## Masterolli (Sep 28, 2010)

hi,
thats not your fault, mabye i have better to check what standards are in use for posting graphs 
I have brought all necessary graphs now in the right format.
started with

pos 1
pos 2
pos 3
pos 4

last graph shows the corner pos behind Front Left Speaker
every graph now is unsmoothed

What do u say

greetings olli


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

The last one looks like it would be the easiest to equalize. Without a SPL meter it’s hard to get response to the Target Curve so REW can auto-equalize. But you can tweak BFD filters on-screen and get a prediction of what response will look like.

Regards,
Wayne


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## Masterolli (Sep 28, 2010)

hi,
ok thats fine that i can use the last graph, with the position in the corner its the best optical room factor 
Is the spl meter only be needed for calibrating the 75db reference level?
When its so could I buy an cheap one for setting up the 75db or what i have to pay attenion for buying an spl meter?

greetings olli


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

If you’re using v4, you can click on the “Trace Adjustments” button (left side of screen). Under it you will find a field to offset the trace ( i.e. response reading). Enter the appropriate number of dB to get your trace down to the Target level. After that, click “Add offset to data.” Then REW can auto-equalize for you. These same functions are available in v5, but the access for them is probably different.

I’d say lower the trace until your 25 Hz peak is at about 77-78 dB. That will put your worse peaks and dips above and below the Target curve. REW v4 will auto-equalize the peaks, but not the dips. You’ll have to manually boost the dips using the EQ Panel.

Regards,
Wayne


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## lsiberian (Mar 24, 2009)

Yeah the last position does look the best of the bunch. It's a weird room so don't be discouraged. Our minds are very good at compensating for room modes so if you get it equalized you should end up with some improved response for sure.


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## Masterolli (Sep 28, 2010)

hi,
Im using v5, i have checked out the auto eq function and played around with.
Correct me when i am not right, the finish is that I try to eq the graph until it hits completly the target curve for best response?
I will try this tomorrow, theres more time for it.

One thing I am thinking about, when i dont know where the 75 db level is and i set it like u said the 25 hz to about 77db and correct then the curve, i dont really know how much cutting and raising the peaks and dips are needed, cause my 75 db lvl is an self determinated without measuring.
But that effects only my volume when i have set the curve to low, i have to raise sub level and when i set it to high, i have to lower sub volume.

Do I understand it technically right.

I think the end of my sub problem is near that never could be possible without your help. Big Thanks

greetings olli


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

> Correct me when i am not right, the finish is that I try to eq the graph until it hits completly the target curve for best response?


More or less, but there’s no need to over-equalize. Any filters with a boost or cut of only 1 or 2 dB will not be audible, so there’s no reason to even use them. Also, don’t use filters that are too narrow. With the DSP1124, that would be bandwidths 1, 2, or 3. All it all, it shouldn’t take more than 4-5 filters to get the job done. The goal is improved sound, not a pretty flat line on the graph. 




> One thing I am thinking about, when i dont know where the 75 db level is and i set it like u said the 25 hz to about 77db and correct then the curve, i dont really know how much cutting and raising the peaks and dips are needed, cause my 75 db lvl is an self determinated without measuring.


For equalizing, it doesn’t matter if the 75 dB Target isn’t a real 75 dB. That will not affect the filters that will be chosen. The 75 dB Target is merely a reference point for the program to equalize with. If you left your trace where it was, way higher than the Target, the REW would try to equalize everything all the way down to the Target – 20 or 30 dB! Naturally, that’s not the way to equalize.




> But that effects only my volume when i have set the curve to low, i have to raise sub level and when i set it to high, i have to lower sub volume.
> 
> Do I understand it technically right.


Yes, after equalizing the sub will not sound as loud as it was before, so you will have to turn it up to blend properly with the rest of the speakers.

Regards,
Wayne


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## Masterolli (Sep 28, 2010)

hi,
after some paying arround i got this...
from my last measuring the first graph, i equalize it until i get the last graph
But for this i had to use more than 4-5 filters some are narrow, i have tried it like u said but dont know maybe i have not enough experience.
Maybe u can say what i have to do, to do it better


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

The filters above 70 Hz probably aren’t necessary. In that range, the main speakers will be overlapping the sub, so those filters probably won’t be heard.

The broad trough between 45-70 Hz, a couple of broad filters could have accomplished the same thing as the four filters you used.

But you’re definitely moving in the right direction. If you saved your measurement, attach the .mdat file to your next post and I’ll load it into REW and see what I can do with it.

Regards,
Wayne


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## Masterolli (Sep 28, 2010)

hi,
i have left the doors open..., but the attached .mdat with closed doors looks quite similar to the graph posted before. 
Would be really nice if u can take a look at the file and show me how it has to be equalized.

Thank you

greetings olli


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

These filters should get you response close to this.















​

Regards,
Wayne


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## Masterolli (Sep 28, 2010)

hi,
yeah thats looks nice with only 4 filters, in some post above u wrote that i have to use low Bandwith, cause of this i have used so much filters.
I have sent your settings to the BFD, tomorrow i will measure once again and look what i get for an response with your settings.

greetings olli


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## Masterolli (Sep 28, 2010)

hi,
i have measured once again, i have add only one more filter to your setup @ about 60hz.
I think the graph is now much more better than without an EQ.
I would let it now how it is, thats good enough for me.

1000 thanks for the members who helped me to get best out of my sub.

greetings olli


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