Needs help with subwoofer integration

[Aubergine]

I have tried to integrate my studio monitors with my subwoofer but the subwoofer behaves erratically. Its frequency response is all over the place. I have put it close to my mains. No walls no obstructions.

Here are my notes.
At 70hz crossover

38 46 Subwoofer is much louder about twice as loud at 40hz compared to mains

46 49 Similar volume

50 70 Mains louder

80hz crossover

Subwoofer louder 38 50

similar volume 51 54

Mains louder 55 70

Subwoofer louder... again? at 75hz and 80hz

85hz mains louder.

It seems to be all over the place and i have no idea how to " fix " it.

 

[abdo123]

Are you capable of doing any EQ at all?

Did you try using the REW room simulator?

 

[Aubergine]

Well i have thought about it and I am looking into it. Could a subwoofer have an innately " bad " frequency response? Like a " normal " speaker. My subwoofer is placed close to my mains. My speakers plays a 70hz test tone just fine. But on my subwoofer i can barely hear it. And at 75hz the subwoofer is suddenly louder than my mains.

 

[Jdunk54nl]

The room plays a huge roll below the Schroder frequency. You must use eq to solve it.
The best way to get a subwoofer to integrate is to get phase between them and the other speakers correct. Easiest way is to use equipment to measure phase like SMAART or Open Sound Meter. I use Smaart.

I just did this the other day when I moved speakers and eqd them. Now, you can't tell where the sub is playing from, even though you can see it. It is weird when it gets done right. Note, this is a pretty bad subwoofer. It is a Polk psw110 with a Dayton 100w plate amp.

 

[Aubergine]

Would something like this work? https://www.ikmultimedia.com/products/arc3/

 

[Jdunk54nl]

What did you use to get your notes in the first post?

 

[Aubergine]

Well I just listened to a bunch of test tones with and without the sub at a moderate level. Staring at 38hz.

 

[Benedium]

Not an expert but everything improved after I moved subwoofer from front wall to beside my couch about 1m from rear wall and nearest side wall. I also point the sub towards front center speaker area. Can even see the improvement in my audyssey graphs.

 

[Jdunk54nl]

I'd suggest getting something to actually measure your room with.

When you hear it louder from something, it may be the sub and mains actually playing together well at that point. Without actual measurements, you can't be sure. Just switching one off and on also doesn't work for many psychoacoustic reasons.

My suggestion for people that don't have a microphone already is to get something like the moto m2 or focusrite 2i2 and the dayton emm-6 microphone. I know a lot of people love USB microphones (I have three), but you just can't do as much if you don't have a good loop back into your sound card. I use my xlr microphones and motu m4 way more often now since I have it.

 

[abdo123]

My suggestion for people that don't have a microphone already is to get something like the moto m2 or focusrite 2i2 and the dayton emm-6 microphone. I know a lot of people love USB microphones (I have three), but you just can't do as much if you don't have a good loop back into your sound card. I use my xlr microphones and motu m4 way more often now since I have it.

Can you elaborate further on that point?

 

[Jdunk54nl]

Sure. Ever try getting time alignment stuff right with REW and a usb microphone? It requires an acoustic loopback. It is super hard and most people give up on it. Just setting distance CAN get you close, but phase is more complicated than physical distance. Everything we do to a speaker impacts the phase (crossovers, eq, time delay, etc.).

If you get an external soundcard that can utlize xlr calibration microphones (dayton emm-6, earthworks, isemcon, etc), you can then do loopbacks on that soundcard. Some external sound cards can do it internally, others you literally just run a TRS/XLR cable from out to in.

If you just use REW, this timing loopback is much easier to get good data out of. But, with this setup, you can now use programs like Open Sound Meter (free) or SMAART (NOT free) and see phase / impulse response / etc. in real time.

No more make change, take sweep, make change, take sweep, like REW does. The REW prediction and alignment tools are decent, but nothing compared to seeing how phase / Impulse response / etc. in real time.

Seeing phase / impulse response / etc. in real time also makes all pass filters much more accessible and easier to integrate. These are crucial to getting multiple speakers properly integrated, it is one of the MAJOR things that set DIRAC room correction apart from the rest. Dirac heavily uses all pass filters to fix phase issues between speakers.

 

[abdo123]

No more make change, take sweep, make change, take sweep, like REW does.

Can't you do the same thing in an RTA window in REW? When the room is modal, phase is equal to the magnitude response anyway.

Not trying to be rude, Just trying to figure out why seperating the amplification from the microphone makes a significant difference.

 

[Aubergine]

I'd suggest getting something to actually measure your room with.

When you hear it louder from something, it may be the sub and mains actually playing together well at that point. Without actual measurements, you can't be sure. Just switching one off and on also doesn't work for many psychoacoustic reasons.

My suggestion for people that don't have a microphone already is to get something like the moto m2 or focusrite 2i2 and the dayton emm-6 microphone. I know a lot of people love USB microphones (I have three), but you just can't do as much if you don't have a good loop back into your sound card. I use my xlr microphones and motu m4 way more often now since I have it.

I am not sure what you mean by listening to them both at once. With the subwoofer out of the picture the frequency response is more consistent in loudness. The change from the subwoofer being " on " is immediate I
just push a pedal that is right at my desk.

I did a quick test. I played a 60z test tone through my speakers with the subwoofer disabled and moved around the entire room. The closer i get to the speakers the louder it gets. The volume is much lower behind them. The subwoofer has similar volume at the front and at the back but its even more directional. So if i am not quite close to the subwoofer the signal is quite low. Maybe my room really accentuates the lower frequencies? Like below 40hz and in a better room i could increase the volume and get more output at 60 70 hz without increasing the sub bass. Because right now i cant increase the gain anymore its twice as loud at 40hz as it is. If i wanted to match 60hz output at desk distance id prob be at three times the volume at 40hz.

 

[Jdunk54nl]

When the room is modal, phase is equal to the magnitude response anyway.
.

Is it though? From what I have measured, that is not the results I have seen. Phase is much more complicated than any single sentence. I have heard them all. Minimum phase statements, non minimum phase statements, when you correct magnitude, you fix phase. etc.

All of them, from my actual measurement experience, are very much oversimplifications. Watch the video posted above about dirac. Look at how much they talk about using all pass filters to fix phase issues.

 

[abdo123]

Is it though? From what I have measured, that is not the results I have seen.

yeah when the phase is aligned you have a healthy addition in the magnitude response of both speaker and subwoofer.

this is the whole point of the phase alignment process.

 

[Jdunk54nl]

yeah when the phase is aligned you have a healthy addition in the magnitude response of both speaker and subwoofer.

this is the whole point of the phase alignment process.

Yes, you can see summation in the RTA window between two speakers. It is possible to see if overall phase is close, but without being able to measure it, you are most likely leaving something on the table.

This is my classroom (from where my above measurements in the beggining of this thread were just taken last week). The sub and the left speaker are literally same distance away from where I was EQ'ing to. If I were to go based on that distance measurement alone and set delay, things summed up ok. By looking at phase information. I had to set my subwoofer delay to 0 and my left speaker to 4.0ms and right speaker to 4.55ms. I also could see that I need an all pass filter in a couple locations between left and right speaker. One being at 800hz, you can see the green line goes a little crazy at that point. An all pass filter will clean this up.

 

[Aubergine]

Yes, you can see summation in the RTA window between two speakers. It is possible to see if overall phase is close, but without being able to measure it, you are most likely leaving something on the table.

This is my classroom (from where my above measurements in the beggining of this thread were just taken last week). The sub and the left speaker are literally same distance away from where I was EQ'ing to. If I were to go based on that distance measurement alone and set delay, things summed up ok. By looking at phase information. I had to set my subwoofer delay to 0 and my left speaker to 4.0ms and right speaker to 4.55ms. I also could see that I need an all pass filter in a couple locations between left and right speaker. One being at 800hz, you can see the green line goes a little crazy at that point. An all pass filter will clean this up.
View attachment 144839

What does it sound like before and after?

 

[Jdunk54nl]

Before any EQ it sounded interesting. Let's just go with that. Speakers were calling attention to themselves and there was not a distinct center image. Sub was also messing up quite a bit.

After just EQ and distance time alignment, there was a better center image, but the sub was calling attention to itself. I had 0ms delay for left speaker and sub and 0.55ms for right speaker. Like I said, everything summed semi-well in moving mic measurments in REW RTA screen, but something was off.

Opened SMAART and measured each speaker and set phase based on that to get 0ms for sub, 4.0ms for left speaker, and 4.55ms for right speaker. Now everything just disappears. You only know a sub is playin when I turn it off and realize you are missing the low end. I also saw a couple spots where I could use all pass filters. I didn't in this case due to time, but may go back and fix that area if I get more time. They are not in frequencies that are a huge deal and it is a narrow area.


Before any EQ:

After EQ: Took about 3 filters on subwoofer with crossover and about 10 filters on each speaker with crossover.

 

[Aubergine]

Well i do have distinct center image and i cannot localize my subwoofer. I want to be able to hear lets say down to 37hz at a moderate volume level. Without! increasing the bass of my system. I want the bass to be at the same level as my mains without the subwoofer.. i only want it to go lower. I cant do that though. Either i have to increase the volume of my whole speaker system or increase the gain on my subwoofer. Am i asking for the impossible?

 

[Jdunk54nl]

No, you are asking for eq. Very possible. Look at my pre eq and post eq measurements above. I did not change sub level. I wanted it to reach down to as low as it could, which meant I needed to get more volume out of it in pre-eq.