Ran REW, now what?

[sud98]

Length mode peak between 30 - 40Hz seems huge.. Exceeds 110dB.. What have you planned to reduce this peak?.

I moved around the sub and can reduce the peaks but the waterfall still looks bad

 

[sud98]

I moved around the sub and can reduce the peaks but the waterfall still looks bad

This at the centre of the wall with 15' and facing the other side wall for the sub

This looks much better, but the waterfall looks much worse

Dont know which is the lesser evil?

 

[liverpool_for_life]

Could you place your subs at diagonally opposite corners along the length of the room and post your measurements?

 

[sud98]

Could you place your subs at diagonally opposite corners along the length of the room and post your measurements?

Well I have only one sub

 

[liverpool_for_life]

Well I have only one sub

Please try 1/4 and 1/2 way along the length.

 

[sud98]

Well this was a half length

 

[liverpool_for_life]

Well this was a half length

So, that leaves 2 positions for you to try along the length: 1/4 or 3/4. Please post those measurements if those placements are possible.

 

[sud98]

So, that leaves 2 positions for you to try along the length: 1/4 or 3/4. Please post those measurements if those placements are possible.

Below is the room mode, so shouldnt the sub be in the 7.5 feet distance? Also, does it matter where I point the sub, as in when I keep it in the middle I point to the side wall versus when I keep it near the front wall I am pointing towards the rear wall?

 

[elangoas]

I moved around the sub and can reduce the peaks but the waterfall still looks bad

I think, dual subs would be one of the solution to reduce the peaks and the improve the decay time in the waterfall..

Below is the room mode, so shouldnt the sub be in the 7.5 feet distance?

Yes.. Right..

Actually the width mode peak is +10dB higher than the length mode peak.. I know you are unable to place it ideally in the room, but were you able to take measurement of the sub in the middle of the room?.. then both the length mode peak at 37Hz and width mode peak at 48Hz should be reduced..

 

[liverpool_for_life]

Actually the width mode peak is +10dB higher than the length mode peak..

Right. 6 ft. from the wall, along the width, which is the indicated modal null position, should fix this peak.

The waterfall is a consequence of your modal issues. Fix them and the decay times will be better. Unfortunately, there isn't a magic fix. Multiple subs and EQ, coupled with some seating location adjustments, can make a big difference though.

 

[Hari Iyer]

I am venturing in the arena of subwoofer for music in another one month and am DIY a H- frame OB sub with a 10" Dayton classic paper cone woofer. Will be using a car subwoofer plate amp which claims class D operation with 200 watts RMS @ 8 Ohms. I will be powering them with a 12 volts, 30 Amps SMPS power supply ( already purchased).

Though the simulation looks ok, but placing them and syncing them with main speakers can be a challenge. To add to my woes, I don't have the liberty of moving them across my room due to want of space. As they are dipole type hoping them to integrate well with my main OB speakers. Keeping my fingers crossed.

 

[sud98]

Right. 6 ft. from the wall, along the width, which is the indicated modal null position, should fix this peak.

The waterfall is a consequence of your modal issues. Fix them and the decay times will be better. Unfortunately, there isn't a magic fix. Multiple subs and EQ, coupled with some seating location adjustments, can make a big difference though.

In the middle of the room facing towards the seats, centre of room.

Left middle of the room facing the seats

Dont see much differences in the waterfall, although frequency graph looks better in the left side wall middle.
I am using the following settings, not sure if they need changes

 

[Hari Iyer]

Sud98, You need to analyze with 5dB vertical scale to get a proper representative outcome. It's surprising to note that the 2 peaks are not double the octave and it looks like there are some heavy boundaries creating these peaks. BTW, is this a ported subwoofer?

 

[sud98]

Post the changes in settings

with the following controls

It is a ported sub

 

[Hari Iyer]

Have you used too much of stuffing in the box?

 

[sud98]

Which box are you referring to. The sub is the one in my signature. These peaks are there even if I run only the left speaker. These are room modes nothing to do with specific sound sources.

 

[Hari Iyer]

Which box are you referring to. The sub is the one in my signature. These peaks are there even if I run only the left speaker. These are room modes nothing to do with specific sound sources.

I am referring to the ported subwoofer box
Are they over stuffed?

 

[elangoas]

Post the changes in settings

Looks like however you position your single subwoofer in the room, the length mode peak hasn't reduced.. Same with width mode peak.. One graph, i can see the width mode has reduced

In the middle of the room facing towards the seats, centre of room.

Also, surprising to see, there is no height mode peak in the response, probably because you sit 1 (or) 2 feet away from back wall..

Anyways, 2 subs along the length of the room, also mid of room width should help reduce the peaks..

Also for subwoofer response, it is suggested not to use any smoothing.. You seem to have used 1/48th smoothing.. You may change it "No smoothing" next time you happen to measure..

 

[sud98]

I am referring to the ported subwoofer box
Are they over stuffed?

It has a slit kind of port. Dont know how much stuffing it has.

 

[sud98]

Looks like however you position your single subwoofer in the room, the length mode peak hasn't reduced.. Same with width mode peak.. One graph, i can see the width mode has reduced


Also, surprising to see, there is no height mode peak in the response, probably because you sit 1 (or) 2 feet away from back wall..

Anyways, 2 subs along the length of the room, also mid of room width should help reduce the peaks..

Also for subwoofer response, it is suggested not to use any smoothing.. You seem to have used 1/48th smoothing.. You may change it "No smoothing" next time you happen to measure..

I have moved the sitting position to 3 feet from back wall. Also, the ear position is half way to the ceiling at around 4.5 feet, so might be a factor in not noticing height modes.