Sub help

khuntim

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Jan 27, 2024
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I am not sure what changed, I used to be able to get different results with RoomFit just by changing the Sub from 0° to 180°, now regardless of sub position, sub polarity or crossover, always looks like this.

if I boost by 3db or so in the Sub settings it doesn't sound right. hoping to get back to something a bit closer with a bit of sub impact.

Speakers are Shanling S0 50hz-20khz, Sub is REL Tzero mkiii 37hz-? Crossover at 60hz. LFE input on sub. RoomFit 30-400hz. Using optical input, have tried USB and AUX.

The sub will not fit behind the TV, unless I figure out a different stand of some sort. floor and walls are concrete. I tried pulling the sub out a bit, can't have it in the walkway, that did nothing..

sub latency tested using all speaker inputs with the Ultra in listening position, Sub always leads the speakers by at least 3ms, up to 40ms using USB.

Microphone is Umik1 using iPad.

Ultra was factory reset after latest firmware.

rf_latest_cr.jpgrf_final_latest_cr.jpg
cube_audio.jpg
sub_right.jpg
sub_left.jpg
sub_0.jpgsub_180.jpg
 
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Don't apply boosts.
Test speakers and subwoofer seperately see how the response is
then compare with the both on, if each response changes a lot then they're cancelling and boosting each other out)
Try moving sub around room.

That's a massive room you need more than a tiny subwoofer, a couple of decent 10"/12" sealed boxes should be enough for music
 
Don't apply boosts.
Test speakers and subwoofer seperately see how the response is
then compare with the both on, if each response changes a lot then they're cancelling and boosting each other out)
Try moving sub around room.

That's a massive room you need more than a tiny subwoofer, a couple of decent 10"/12" sealed boxes should be enough for music

So use Non-boost mode? I can try this. Roomfit used to work differently, I'll mess with it some more.

Only options are to move the sub left and right under the TV shelf, I have tried maybe 8 positions in the small space under the TV and same results, so I just moved it back to the middle.

So power off the speakers and see if the sub has more power. worth a try.

in the past, when I changed the sub polarity (and latency for that polarity) that would make a big difference, now the same...

as far as the bass, this woofer is fine in this space, just not sure what happend

Thank you
 
So use Non-boost mode? I can try this. Roomfit used to work differently, I'll mess with it some more.

Only options are to move the sub left and right under the TV shelf, I have tried maybe 8 positions in the small space under the TV and same results, so I just moved it back to the middle.

So power off the speakers and see if the sub has more power. worth a try.

in the past, when I changed the sub polarity (and latency for that polarity) that would make a big difference, now the same...

as far as the bass, this woofer is fine in this space, just not sure what happend

Thank you
Out of curiosity, does closing the bedroom door make a difference to the measurement results?
 
Correct use non boost mode, boosting uses lots more power. You only want to apply cuts

Need raw response of the sub and raw response of the speakers, so you can see what it's like. If it changes, and speakers & sub response change then crossover isn't right

That massive dip at 60hz could sub and speakers cancelling each other out.

Correct, close windows and doors. That will effect bass response.
 
use REW room sim to get an idea where best location of the sub should be,

Basically need something like this, this is for speaker but principle is the same, how it interacts between the crossover point and over the range

If you imagine the subwoofer is the blue line, green is the speakers. Only one active during testing.

Then plot another response with both switched on. Compare the individual sub and speaker responses, to the combined response It should look similar, but flatter with both of them on.
 

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I am not sure what changed, I used to be able to get different results with RoomFit just by changing the Sub from 0° to 180°, now regardless of sub position, sub polarity or crossover, always looks like this.

if I boost by 3db or so in the Sub settings it doesn't sound right. hoping to get back to something a bit closer with a bit of sub impact.

Speakers are Shanling S0 50hz-20khz, Sub is REL Tzero mkiii 37hz-? Crossover at 60hz. LFE input on sub. RoomFit 30-400hz. Using optical input, have tried USB and AUX.

The sub will not fit behind the TV, unless I figure out a different stand of some sort. floor and walls are concrete. I tried pulling the sub out a bit, can't have it in the walkway, that did nothing..

sub latency tested using all speaker inputs with the Ultra in listening position, Sub always leads the speakers by at least 3ms, up to 40ms using USB.

Microphone is Umik1 using iPad.

Ultra was factory reset after latest firmware.

View attachment 26770View attachment 26771
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View attachment 26774
View attachment 26775
View attachment 26776View attachment 26777
As a first experiment I'd suggest just increasing the sub crossover frequency in WHA to 100Hz and see if that fixes/changes the dip after re-running RoomFit. Remember to disable MMM so you get the Individual Channel RoomFit option.
 
As a first experiment I'd suggest just increasing the sub crossover frequency in WHA to 100Hz and see if that fixes/changes the dip after re-running RoomFit. Remember to disable MMM so you get the Individual Channel RoomFit option.

I tried 100hz, and quite a few others and came up the same, will have to try again. I was wondering how I lost the left/right option, thanks
 
I tried 100hz, and quite a few others and came up the same, will have to try again. I was wondering how I lost the left/right option, thanks
Here I mainly want to see if there's any change, e.g. if the dip moves in frequency or changes shape.
Another thing I'd suggest to try is to disable the sub in WHA and re-run RoomFit. Please post RoomFit screenshots for both tests (the one with 100Hz sub crossover and the other with sub disabled).
What we're trying to do first is just to identify the cause of the dip, then we'd have some idea what we could do to try and fix it.
 
Here I mainly want to see if there's any change, e.g. if the dip moves in frequency or changes shape.
Another thing I'd suggest to try is to disable the sub in WHA and re-run RoomFit. Please post RoomFit screenshots for both tests (the one with 100Hz sub crossover and the other with sub disabled).
What we're trying to do first is just to identify the cause of the dip, then we'd have some idea what we could do to try and fix it.

0_60hz_cr.jpg180_60hz_cr.jpg
0_100hz_cr.jpg180_100hz_cr.jpg
no_sub_cr.jpg
 
Perfect!
So this tells us a few things:
1) Loudspeaker and MLP placement is OK, no significant LBIR or SBIR dips are visible in the last picture.
2) The issue seems mainly caused by the crossover to the sub, and quite possibly by the automatic sync delay settings.

Can you tell me all of the settings values you have configured under the Sub Out menu in WHA? Do you have both "Subwoofer Bypass Mode" and "Main Speakers Output Bass" options disabled?

How are the physical potentiometers on your Rel subwoofer set? Is the "crossover" knob set to maximum value (120Hz)? What is the position of the phase switch?


EDIT: Disregard the above, after a closer look the dip is visible even in the last picture with the sub output disabled - it just seems less severe due to a large difference in vertical scale.

This in mind, I suspect the dip might be caused by the position of your listening spot.

To test this can you do another run of RoomFit with 60Hz crossover (i.e. your original sub settings), but now measure e.g. 50cm further in front of where you actually sit?
 
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looked like this using iPad, since Android asks me to point my phone and app goes upside down sometimes.

final_ipad_cr.jpg

then after moving the mic 50cm forward (front of sofa) using Android again, Umik1 mic always:

50cm_cr.jpgfinal_50cm_cr.jpg
 
So does that mean the deep wide dip is due to the listening position close to the rear wall?
That seems to be the main cause, indeed. We can see that severity of the dip decreased by about half (-10dB to -5dB) when measuring just 50cm further in front of the main listening position.
 
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