# Help with front right speaker nulls



## Ellisdj (Mar 16, 2012)

Hi

I wonder if I can get a bit of advice re the nulls in the response of my front right speaker.

I put it partially down to me not being able to treat the right wall as there is a window there.
I wonder if there is anything else I can do either behind the speaker on the front wall or at the other end on the back wall.

I cant have corner panels as much as I would love to as its not allowed with the decor.

This is my response - aplogies if its not to the format or scale - let me know and I will change it?
I am crossing over at 80hz with 24db octave - I have eq'd out the big peak at 60hz











Thanks for any help


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## bpape (Sep 14, 2006)

Can you give a little more info about your room size, seating location, sub location, etc?


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## jim1961 (Apr 8, 2011)

Maybe change the scale to 5db increments instead of 8db ones.

Like to see the un-EQ'd version of your FR

+1 to what Bryan said.


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## Ellisdj (Mar 16, 2012)

that is uneq'd i will try and change the scale and ber back with dimensions and pics when baby asleep

How do you change the scale sorry?


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## jim1961 (Apr 8, 2011)

Ellisdj said:


> that is uneq'd i will try and change the scale and ber back with dimensions and pics when baby asleep
> 
> How do you change the scale sorry?


Minor thing, dont worry about it. 

Might try crossing over the sub a bit higher, say 120-140hz. This may fill in the gap between 60hz and the 150hz region. 

Without seeing the other speakers response, cant say for sure this is a good idea though. EQ'ing 60hz down must make it very bass shy compared to whats happening 150hz and above. Better to try to full the null I think.


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## Ellisdj (Mar 16, 2012)

Room Size is

570cm or 18.7feet long
365 cm or 12 feet wide
243 cm or 8 feet high

The listening position is central to the width and 270 cm from the back wall

I have attached pictures - they show the panels I have made and fitted - please excuse the everywhere - I did not tidy up before taking the shots - the house is still messy from the weekend.




























This is my left channel response by comparison









Please bear in mind I am crossing over at 80htz so the resposne should track the line going down as that is the target. Both these responses are speaker only no sub


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## jim1961 (Apr 8, 2011)

Ellisdj said:


> Room Size is
> 
> 570cm or 18.7feet long
> 365 cm or 12 feet wide
> ...


Now I am confused. This FR isnt with the sub? Or is it?

Put both channels on one plot for easy comparison.


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## Ellisdj (Mar 16, 2012)

Both the readings I have posted here are with the sub off.
I was checking to see how the response tracked the 24db roll off through the crossover.

I haven't run sweeps with the sub - I have the sub setup as a hard knee house curve. 

My main area of current focus was to try and improve above the crossover response for my front R and L if possible.

I am sure I can get away with a few more panels before the mrs kicks me out. I wondered if a type of panel in the corner (not across) on the front or back wall would help?
Or maybe the use of a specific panel such as the scopus tuned in the front or back corners?


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## Ellisdj (Mar 16, 2012)

This is both channels as requested - I had to use the measured tab in Rew 4 as I couldnt work out any other way to overlay.










Gold is Right Front Speaker, Blue is left Front speaker - again no sub


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## Ellisdj (Mar 16, 2012)

I have been looking at options of where stuff is in my room - I am pretty limited due to futniture plugs etc.

However - Tri Traps look great and potentially the ideal solution - however I think I cna only have one in a bottom corner - picture below.











It is the side I have the main speaker issues which I am hoping may have a good effect?

Having 8 in a room the results speak for themself - however what about 1 in a corner?


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## jim1961 (Apr 8, 2011)

I really think you should be running your measurements WITH the sub. 

Phase and timing play a huge role in how two frequency curves combine. Making two converge the way you are trying to do only works when all the frequencies in question are in phase. With the sub way off to the left, how the right speaker combines with the sub will be very different than how the left one does.

If you want each channel to combine smoothly, the only way to know is to have the sub in the measurement data.


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## Ellisdj (Mar 16, 2012)

You are right there and I will do that.

becuase I was lookign for advice 80 -100htz upwards a lot of that my sub wont be affecting hence why I didnt post full range plots.

I am waiting for a new mic to turn up and when it does I will run sweeps with the speakers and sub.

It has made me look at / think about options for better acoustics which is a good thing.
I am going to make a few enquiries with GIK re a the effect of a single tri trap in a corner and maybe extra thicker absoprtion panels on the rear wall i.e 2 244's (the art panel versions) instead of 1 2inch with a 1inch air gap home made


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## jim1961 (Apr 8, 2011)

I would put bass traps behind each speakers in those corners. 

Fundamentally, room treatment begins with adequate bass trapping, and that almost always starts with bass trapping in all corners. Then treating first reflection points (side wall, floor and ceiling).

Once the above is done, many find this enough for good sound. Of course, the Rabbit hole goes much deeper if your brave enough to take a look


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## Ellisdj (Mar 16, 2012)

jim1961 said:


> I would put bass traps behind each speakers in those corners.
> 
> Fundamentally, room treatment begins with adequate bass trapping, and that almost always starts with bass trapping in all corners. Then treating first reflection points (side wall, floor and ceiling).
> 
> Once the above is done, many find this enough for good sound. Of course, the Rabbit hole goes much deeper if your brave enough to take a look


Its the corners that I am not allowed to do, they look the worst of all treatments - flat on the wall behind the speakers I can probs get away with - but I dont know whether that will have much effect balanced against the cost. I would do it if it was worth it

Its the rear wall corners - one in particular I have some leway - I could just about squeeze a tri trap in there - the opposing corners has plugs we regularly use and the tri trap would block them.


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## jim1961 (Apr 8, 2011)

Ellisdj said:


> Its the corners that I am not allowed to do, they look the worst of all treatments - flat on the wall behind the speakers I can probs get away with - but I dont know whether that will have much effect balanced against the cost. I would do it if it was worth it
> 
> Its the rear wall corners - one in particular I have some leway - I could just about squeeze a tri trap in there - the opposing corners has plugs we regularly use and the tri trap would block them.


Do the ones you can then.


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## Ellisdj (Mar 16, 2012)

will 1 tri trap make a noticeable difference ? I would think it would but if it doesn then I need to rethink


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## jim1961 (Apr 8, 2011)

Ellisdj said:


> will 1 tri trap make a noticeable difference ? I would think it would but if it doesnt then I need to rethink


Not sure what you mean by tri-trap, but even one "done right" corner trap (floor to ceiling 24" across corner) will make a measurable difference in a room that has none. 

Noticeable difference depends on ones attention to detail and expectations. 

There isnt any way to forecast the outcome in a subjective way.


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## Ellisdj (Mar 16, 2012)

Thsi is what I meant http://gikacoustics.co.uk/product/gik-acoustics-tri-trap/

I can literally only have one, floor to 4 foot above - not 2 stacked on top of each other as is ideal - I dont think she will let me have that, she is already moaning about what I currently have


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