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Is there a way to predict what subwoofers will sound like in an irregularly shaped room?

1869 Views 18 Replies 8 Participants Last post by  Lindros88
Are there any room simulators that are compatible with irregularly shaped rooms? I'm really interested in adding two more VTF3 MK5's to my room, bringing me up to four total.

However, my room isn't completely symmetrical, due to my back wall being a closet, which I removed the four doors from, to increase the size of the room, add bass trapping and fit my projector.

I'm looking for some way to predict what adding two more subs to my room would sound like. My room is 16x12 and I would be putting all four subs in corners. I'm worried it could end up sounding worse than two and I'm not looking to take any chances, since they don't offer free returns. Any recommendations? Thanks.
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Are there any room simulators that are compatible with irregularly shaped rooms? I'm really interested in adding two more VTF3 MK5's to my room, bringing me up to four total.

However, my room isn't completely symmetrical, due to my back wall being a closet, which I removed the four doors from, to increase the size of the room, add bass trapping and fit my projector.

I'm looking for some way to predict what adding two more subs to my room would sound like. My room is 16x12 and I would be putting all four subs in corners. I'm worried it could end up sounding worse than two and I'm not looking to take any chances, since they don't offer free returns. Any recommendations? Thanks.
If the current sound field is good then putting the new ones on top of the old ones would be low risk possibility.
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Take an rew sweep at each seat, you’ll probably have an area with boomy response or other issue, that’s a good possibility of a sub position. Last house was open plan, it’s a challenge for bass, but the one bad seat was made way better with subs flanking the main seating, which put one sub near the bad spot.
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Are there any room simulators that are compatible with irregularly shaped rooms? I'm really interested in adding two more VTF3 MK5's to my room, bringing me up to four total.

However, my room isn't completely symmetrical, due to my back wall being a closet, which I removed the four doors from, to increase the size of the room, add bass trapping and fit my projector.

I'm looking for some way to predict what adding two more subs to my room would sound like. My room is 16x12 and I would be putting all four subs in corners. I'm worried it could end up sounding worse than two and I'm not looking to take any chances, since they don't offer free returns. Any recommendations? Thanks.
Yes. Use rew and mso.
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If the current sound field is good then putting the new ones on top of the old ones would be low risk possibility.
The current sound field is a bit too uneven. There are some dips on both sides of the room. I'm hoping to improve consistency across the most amount of listening positions. I feel like I can't go wrong with 4 subs in room corners.

My room isn't symmetrical, but it's not extremely asymmetrical either. I figure I could at least get some idea what to expect from the REW room simulator.

What surprised me about the room simulator is that the frequency response at the MLP doesn't change at all when adding 2 more subs in the other corners. There's no difference at the MLP between 2 opposite corner subs vs 4 subs in all corners? I didn't expect that.
My room isn't symmetrical, but it's not extremely asymmetrical either. I figure I could at least get some idea what to expect from the REW room simulator.
Don't use the simulator. You can use one of your subs, REW and MSO to predict an actual final result. Take the one sub and measure it in every potential location (even mid-wall locations). If you want to find the absolute best responses, be sure to face the sub in all 4 directions at each location (maintain 3" from driver side and wall). Be sure to use acoustic reference timing on all sweeps.

Once you have all the data, you can use MSO to select the 4 best locations and it will also tell you what delays to use for each sub.

At that point you can decide if 4 subs will get you where you want or not.
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Don't use the simulator. You can use one of your subs, REW and MSO to predict an actual final result. Take the one sub and measure it in every potential location (even mid-wall locations). If you want to find the absolute best responses, be sure to face the sub in all 4 directions at each location (maintain 3" from driver side and wall). Be sure to use acoustic reference timing on all sweeps.

Once you have all the data, you can use MSO to select the 4 best locations and it will also tell you what delays to use for each sub.

At that point you can decide if 4 subs will get you where you want or not.
Thanks for the reply. I'm going to have to get a UMIK-1, right? My Audyssey mic isn't going to work for this, is it? Each time I move the sub, should I be re-calibrating with Audyssey? In my case, I won't have a ton of flexibility outside of corner placements.

I don't plan on using a MiniDSP. I have an XT32 AVR with SubEQ HT, so I figured I would be able to run each pair equidistant to the MLP and get pretty good results.
Thanks for the reply. I'm going to have to get a UMIK-1, right? My Audyssey mic isn't going to work for this, is it? Each time I move the sub, should I be re-calibrating with Audyssey? In my case, I won't have a ton of flexibility outside of corner placements.

I don't plan on using a MiniDSP. I have an XT32 AVR with SubEQ HT, so I figured I would be able to run each pair equidistant to the MLP and get pretty good results.
Yes you need a calibrated mic. Do not use audyssey while doing sub alignments. Wait for all subs to be aligned.

You will likely need different delays for each sub so if you need four plan for a minidsp. MSO will let you know though.
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Yes you need a calibrated mic. Do not use audyssey while doing sub alignments. Wait for all subs to be aligned.

You will likely need different delays for each sub so if you need four plan for a minidsp. MSO will let you know though.
I'm going to order a UMIK-1 once they are back in stock at cross-spectrum. I'm officially in over my head, but I just watched a really good hour and a half REW/miniDSP tutorial on Youtube and now all of this seems way less intimidating. Thanks for your help.
I'm going to order a UMIK-1 once they are back in stock at cross-spectrum. I'm officially in over my head, but I just watched a really good hour and a half REW/miniDSP tutorial on Youtube and now all of this seems way less intimidating. Thanks for your help.
I’d order now. I ordered one a month or so ago when out of stock and it was delivered within a few weeks, all while the website continued to say out of stock.
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I'm going to order a UMIK-1 once they are back in stock at cross-spectrum. I'm officially in over my head, but I just watched a really good hour and a half REW/miniDSP tutorial on Youtube and now all of this seems way less intimidating. Thanks for your help.
You don't need the cross spectrum version. It isn't going to do anything for the average home user. The standard UMIK is accurately calibrated to a reasonable tolerance. Order from one of the many other outlets like parts-express. The additional cross labs calibration does nothing to help you compare locations and align subwoofers. The only thing that extra calibration can do is give you a more accurate absolute SPL reading.

So for example, a non-cross spectrum labs UMIK will give you essentially the exact same shape of curves but the peaks might read .5dB different. Does that matter for alignment? No. When does it matter? It only matters if you are trying to find out if you are hitting 115dB at 10Hz or 115.3dB at 10Hz. So in reality, only those people doing peak SPL measurements to compare different subwoofers for reviews actually need the cross spectrum level of calibration. Since you are doing measurements in room, only relative accuracy matters and cross sprectrum won't improve that one iota.
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You don't need the cross spectrum version. It isn't going to do anything for the average home user. The standard UMIK is accurately calibrated to a reasonable tolerance. Order from one of the many other outlets like parts-express. The additional cross labs calibration does nothing to help you compare locations and align subwoofers. The only thing that extra calibration can do is give you a more accurate absolute SPL reading.

So for example, a non-cross spectrum labs UMIK will give you essentially the exact same shape of curves but the peaks might read .5dB different. Does that matter for alignment? No. When does it matter? It only matters if you are trying to find out if you are hitting 115dB at 10Hz or 115.3dB at 10Hz. So in reality, only those people doing peak SPL measurements to compare different subwoofers for reviews actually need the cross spectrum level of calibration. Since you are doing measurements in room, only relative accuracy matters and cross sprectrum won't improve that one iota.
My UMIK-1 is supposed to come either today or tomorrow. What would you say is the best tutorial available for MSO?
My UMIK-1 is supposed to come either today or tomorrow. What would you say is the best tutorial available for MSO?
There’s a new tutorial being prepared along with an easier to use version of mso.

You should ask in the MSO thread.
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My UMIK-1 is supposed to come either today or tomorrow. What would you say is the best tutorial available for MSO?
Learn REW first then move on to MSO. You have to have the REW data to import into MSO. Your REW measurements need to use acoustic reference timing.
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To answer the thread title question... Yes. But if you have to ask you can't afford it.

Keith Yates BassCamp/JBL FLO computational fluid dynamics simulation can do this before the room is built (or after). Last I checked $10k was the price of entry, with the $20k option increasing the number of potential subwoofer locations for simulation.

Boundry element modeling can also give you an idea of what response you'll end up with, but not as granular as the KYDG approach.

For the real world where the rest of us live, good advice given so far...REW, MSO and experimentation are you friend!
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Are there any room simulators that are compatible with irregularly shaped rooms? I'm really interested in adding two more VTF3 MK5's to my room, bringing me up to four total.

However, my room isn't completely symmetrical, due to my back wall being a closet, which I removed the four doors from, to increase the size of the room, add bass trapping and fit my projector.

I'm looking for some way to predict what adding two more subs to my room would sound like. My room is 16x12 and I would be putting all four subs in corners. I'm worried it could end up sounding worse than two and I'm not looking to take any chances, since they don't offer free returns. Any recommendations? Thanks.
what you exactly need is fluid dynamics to evaluate the pressure in the room along with the decay. The most important for any subwoofer is to find the right positions in the room so that you should get the following:

1. No steep peaks or deep nulls in the seating position.

2. To find the right locations of the subs for maximizing the energy at the seating position.

3. Along with the above you should also have bass decay well in the room for which basstraps should be designed as per the above response.

4. Now all the above cumulated conditions should work to get ideal locations of the subs and also basstraps should be designed as per the above conditions. Quite complex but when done right you will not have atleast those crazy dips and peaks.


If a DSP is used only frequency domain correction is done but time domain you don`t have control over how wave should attenuate in the room. Check with InventionAudio they have developed an algorithm for solving these problems in the room.
3150946
3150947
3150948



Same thing after the right positions and basstraps designed for that space.

3150950
3150949

3150951


you can also see maximum energy being concentrated at the listening position. As what is the point of having big subs but eventually not able to extract maximum spl possible with it along with proper bass decay and normalized response.
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what you exactly need is fluid dynamics to evaluate the pressure in the room along with the decay. The most important for any subwoofer is to find the right positions in the room so that you should get the following:

1. No steep peaks or deep nulls in the seating position.

2. To find the right locations of the subs for maximizing the energy at the seating position.

3. Along with the above you should also have bass decay well in the room for which basstraps should be designed as per the above response.

4. Now all the above cumulated conditions should work to get ideal locations of the subs and also basstraps should be designed as per the above conditions. Quite complex but when done right you will not have atleast those crazy dips and peaks.


If a DSP is used only frequency domain correction is done but time domain you don`t have control over how wave should attenuate in the room. Check with InventionAudio they have developed an algorithm for solving these problems in the room.
View attachment 3150946 View attachment 3150947 View attachment 3150948


Same thing after the right positions and basstraps designed for that space.

View attachment 3150950 View attachment 3150949
View attachment 3150951

you can also see maximum energy being concentrated at the listening position. As what is the point of having big subs but eventually not able to extract maximum spl possible with it along with proper bass decay and normalized response.
Cost?

This appears to be the same fluid dynamics simulation that is patented by Keith Yates design group and licensed by JBL/Harman at the $10,000/$20,000 USD price point (as I understand it)
I guess they have found a way to do it in CFD and their method seem choosing the location in the selected spots. Here its quite different we are able to get much better symmetrical distribution and as well as all the above conditions. As forum rules are not supposed to discuss about pricing but its done at much lower costs. You can contact "Invention Audio" via phone to get costings information if you are planning to make a dedicated room for Home theater.
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Learn REW first then move on to MSO. You have to have the REW data to import into MSO. Your REW measurements need to use acoustic reference timing.
I'm not going to bother with MSO. I'm going to get two more subs and try using a minidsp to align all of them. I already got the minidsp and have been experimenting with my two subs.

Unfortunately, I have been getting worse results with the minidsp than I am able to get when calibrating through the AVR via the two independent sub outs. Though the minidsp probably really shines with more than 2 subs.

The green line is a calibration through the AVR and the blue line is through the minidsp. It seems no matter what delay I set in the minidsp, XT32 always did it better, with the exception of the left seat.

MLP
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Right seat
3153111


Left seat
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