Genelec Dual Sub Optimisation

[Kervel]

In my room (14 m²) possibly due to small distances to the boundary surfaces both speakers have some nulls below 120 Hz. There is a single subwoofer in the right corner. For both speakers GLM determines a compensation of -3 dB and -4 dB. So corner-loading is not enough ...
Would adding a second 7350 (stereo-)subwoofer in the left corner and setting crossover higher probably help mitigate both problems?

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Your subs response looks really good until 100hz, so a crossover at 80 should be good. Your right speaker looks really good above 80hz. Only your left speaker has a dip at 100hz, but a very steep one (very high q), so I doubt its audible. A second sub wont help in terms of frequency response (it would increase SPL capabilities).

 

[Rundalnurg]

Great thread
wish i had read it before buying two 10" Gen subs. I am using them with non-Gen mains. This is for a control room and im trying to flatten my 100hz null. Room is treated to the max. Before I return them I'm going to run some more tests. But...

issues
- fixed crossover at 85hz when using non-glm mains
- separately eqing each sub defeats purpose of two subs outputting the same thing?
- no time alignment between subs in glm

solutions with the gens
- find a variable analog HP for the mains (thats proving hard)
- minidsp (which one)? https://www.minidsp.com/products/minidsp-in-a-box/flex

ditch Gens
start from scratch

I am happy to say get the eq / gain sorted in glm... use some filter solution to get my crossovers good for my null(s). time align manually and using REW happy to not have it all done for me. But its a lot to think about.

 

[Ellebob]

Easy solution if possible. Move the seating. If you are sitting in a null from a room mode applying a filter will not work. Doesn't matter if using two subs. If a null is from a room mode it happens at certain locations in the room. Typically near quarter and half points of a dimension in rectangular rooms.

Two subs are about good placement and using volume and phase between them to diminish the null. Might not totally eliminate. Then you have to integrate with the mains. Mini DSP with a lot of trial and error time is easiest way to do it. Which minidsp model depends on equipment and use? Is this control room stereo or multichannel?

If the null is not from a room mode you need to find it's source. Is it from SBIR? Poor crossover integration? Other acoustic problem? A lot to figure out.

 

[Rundalnurg]

2 channel control room
null is floor to ceiling mode i think
ive found best of all possible mains and seating postion

for mini dsp im looking for analog out 2 mains and 2 subs. but would spend 500 over 250 for better connectors than RCA

i am on a real multi day journey of sub placement and nothing looks good. But my crossover is stuck at 85 hz

 

[Rundalnurg]

Orange is the best response I can get positioning wise with the subs and GLM software with crossover set to 85
white is with no sub and my mains at full freq

 

[Ellebob]

If it is from a height mode then the solution is to have one sub near the ceiling and one on the floor. You won't fix a height mode with subs on the floor. You will still need the DSP.

 

[Rundalnurg]

thats going to be a hard stand to build

 

[Ellebob]

We don't run into problems with height modes too often but that is because in most homes people's ears aren't in the half or quart point of height dimension. I am guessing your ear height is higher than most couches/recliners like near 4 feet for an ~8 foot ceiling or you have pretty tall ceilings?

 

[Rundalnurg]

maybe im wrong about it being a height mode but when i move traps to the floor there its greatly impacted
my ears are at 51" and my room is 10 ft tall. Ive done a ton of testing and I originally made some guesses with the room sim.... but non of the REW room sim stuff panned out. Biggest issue i guess for my making a little headway is not having crossover control. I do like what the GLM stuff does when I calobrate vs no calibration and I test it in REW at least just in freq response. But no ability to test the crossover where the issues really are.

now say maybe I can attack that with the minidsp
but bang for buck idk that the gens are doing me favors im like 6k deep on them
and then at that I find they clip kind of early

 

[Rundalnurg]

after a TON of tests
and using a minidsp 2x4 to set the crossover above my 100 hz problem to 120 hz + lots of treatment under my desk and screens
the 2 sub thing yielded
white = pre sub
yellow is = dual sub

nothing worked until something did ill spare the details for now of the sub placement and settings as its going to be different in different rooms
symmetry in my room actually worked best. its a symmetrical room after all but i tried everywhich way and the REW room sim suggested mostyly asymmetrical setups. but alas testing yielded.

i dont looooove the mini dsp and will return it for a different crossover solution but thts a mixing mastering thing... thankd for chat above yall it helped.

the Gen calibration helps a ton too still and you just cant set the crossover higher than 85 hz - if your mains are not genelec

 

[nocturne]

GLM recently got an update, which was posted to the Genelec facebook group, so I inquired about the possibility of multi sub support. I got a response back saying they still do adjustments based on the measurements of separate subs, but "we're discussing alternative options" - fingers crossed