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PostPosted: Mon Apr 18, 2022 11:04 pm 
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one consideration on the cloud - drop the front down about 4-5"

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PostPosted: Mon Apr 18, 2022 11:12 pm 
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Weird changing info..... Clearly the 90Hz is SBIR because the frequency is changing with distance from the Front Wall.

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PostPosted: Tue Apr 19, 2022 12:54 am 
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L&R measurements.
Fyi: these ones have the rack/table that was missing earlier.


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Last edited by anodivirta on Tue Apr 19, 2022 3:08 am, edited 1 time in total.

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PostPosted: Tue Apr 19, 2022 2:21 am 
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DanDan wrote:
Weird changing info..... Clearly the 90Hz is SBIR because the frequency is changing with distance from the Front Wall.
gullfo wrote:
one consideration on the cloud - drop the front down about 4-5"


Thank you Glenn and Dan.

I can try to lower the cloud, if I drop it ~10cm it will be in level with the fronts dropped ceiling.
Dont know if its easy to see in pictures, but first 120cm of room ceiling has acoustic panels 40cm lower and then this 120x120cm cloud 30cm lower.

I'm sure it doesnt help this weirdness that measurements are done during very long time perioid and I think there has even been 4sets of speakers involved (starting with pa-speaker to amphions and finally smaller and bigger genelecs.)+changes in listening position.


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PostPosted: Wed Apr 20, 2022 1:51 am 
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Looking for better position on right speaker.
Fyi: speaker still has previous glm correction on.


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PostPosted: Mon Apr 25, 2022 4:10 am 
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Looking for correct location:
Moving the speaker 10cm at a time
Away from centerline=red
Away to back=blue


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PostPosted: Mon Apr 25, 2022 11:00 pm 
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it was very annoying to notice how big changes I can get when changing the speaker location,
but also very annoying to notice that "best" location is very much compromise between -first from usability, but
also one position that is good for example 80hz is bad for 150hz etc.

I noticed that using noise and RTA in REW was very revealing and using smaller speakers allowed me to move almost freely and test everything quickly,
bigger speakers are almost 30kg each+weight of those cinder blocks so saved my back :)

Next step I was planning is to get new measurements with main speakers in the "best" location, then test lowering the cloud.

Looking at room mode- calculator and having found MLV (60cm wide roll, weight 7.3 kg/m2) I thought about trying to make few limp membrane traps targeting that ~40hz


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PostPosted: Tue Apr 26, 2022 12:41 am 
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note that treating 150hz should be easier than 80hz. also note that bumps are be partly solved with eq whereas nulls cannot.

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PostPosted: Tue Apr 26, 2022 1:12 am 
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gullfo wrote:
note that treating 150hz should be easier than 80hz. also note that bumps are be partly solved with eq whereas nulls cannot.

Thanks! So in real world I should maybe focus those frequencies and not that 40hz?
I'm just horrified by that long decay times in bottom range:)


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PostPosted: Tue Apr 26, 2022 5:55 pm 
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or if I rephrase:
is it realistic for unexperienced builder like me to get get much better low frequency decay times in a limited space like mine?

Looking at the acousticmodelling.com it seems that you could make decent size (or ~25cm deep) limp mass-thingy that would work on low enough.
But thats the simulation :D


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PostPosted: Wed Apr 27, 2022 12:39 am 
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the 40hz is likely the fundamental and the 80 is the harmonic on that. first try would be to cut some on the 40hz via EQ and see what that does. then if no on the EQ - the 40hz with a limp membrane trap would be good. not sure it needs to be 25cm deep, maybe 15cm though... so it seems that the 150hz is likely the second one to fix and again a membrane trap may be the right option.

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PostPosted: Wed Apr 27, 2022 7:27 am 
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Your Waterfall axes are quite hard on you. Typically I use only about 45dB Vertical scale and whatever time is needed to see the decays fully, typically more like 500mS or more. The Lowest Mode is always tough. I have 4 large Corner Traps but still need Dirac Live to finally tame my 35Hz.

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