Is there any benefits to 3 subs Vs 2 sub setup

B

bomt697

Audioholic Intern
Hello,

I am considering on adding a 3rd subwoofer to
my current duel HSU VTF-3 MK5 setup (3rd being the same sub). I have a semiclosed room that’s 3200 cubic feet. Will be using miniDSP 2x4HD to calibrate. What are other advantages would I gain besides headroom? Please advise. Thanks
 
ryanosaur

ryanosaur

Audioholic Warlord
If you are taking measurements and can find the locations where your Subs will positively sum for improved room performance, then your benefit will be less disruption by room mode and smoother seat to seat performance. By strategically placing the Subs, a la Geddes' approach, you should be able to and possibly could achieve a maximally flat performance in your listening area.
 
3db

3db

Audioholic Overlord
Hello,

I am considering on adding a 3rd subwoofer to
my current duel HSU VTF-3 MK5 setup (3rd being the same sub). I have a semiclosed room that’s 3200 cubic feet. Will be using miniDSP 2x4HD to calibrate. What are other advantages would I gain besides headroom? Please advise. Thanks
I recently dialed in a 3rd sub in my greatroom (multi use living space consisting of kitchen, dining, and living area in one big unenclosed space and open to the hallway) and it improved sub response that much more across my sitting area.
 
Last edited:
B

bomt697

Audioholic Intern
I recently dialed in a 3rd sub in my greatroom (multi use living space consisting of kitchen, dining, and living area in one big unenclised rpsce and open to the hallway) and it improved sub respinse that much more across my sitting area.
How did it go? How did you calibrate it?
 
3db

3db

Audioholic Overlord
I calibrated them using REW + UMIK1 measurement mic and a miniDSP 2X4HD and followed this these links...


 
A

Alastair

Audiophyte
This is an interesting topic as I am re thinking my entire system and in particular how to maximise 3 subs.
A challenge is that I would only be able to place the subs in the corners of the room, no scope to move them around E.g 1/4 way into the room.I also have a fixed listening seat close to the back wall. And I can’t do any treatments as this is a shared space.
I am also wondering about the value of going from 2 to 3 subs when there are so many placement constrains.
I don’t feel I have a bad sound now with 1 but I also think you get used to what you are used to!
Having recently watched the 3 great YouTube videos with Gene and Anthony on getting good bass, I do think improvements can be made.
 
3db

3db

Audioholic Overlord
This is an interesting topic as I am re thinking my entire system and in particular how to maximise 3 subs.
A challenge is that I would only be able to place the subs in the corners of the room, no scope to move them around E.g 1/4 way into the room.I also have a fixed listening seat close to the back wall. And I can’t do any treatments as this is a shared space.
I am also wondering about the value of going from 2 to 3 subs when there are so many placement constrains.
I don’t feel I have a bad sound now with 1 but I also think you get used to what you are used to!
Having recently watched the 3 great YouTube videos with Gene and Anthony on getting good bass, I do think improvements can be made.
Check with my post #6 above and start at post 24 on this link.
https://forums.audioholics.com/forums/threads/3dbs-great-room-mainfloor-townhouse-open-concept-setup.113655/page-2#post-1469217
 
A

Alastair

Audiophyte
Thanks for the direction. I am only on my iPhone but it reads like you have achieved some really good results.

I’ve got REW, a UMIK, a 2x4 miniDSP and have some experience with fiddling (including Dirac) but am by no means an expert.

I am thinking that I might have to reach out to an expert (based in the U.K.) as I am just too inefficient when it comes to set up. I like playing around and experimenting but too slow and don’t have enough time in the shared space!
 
3db

3db

Audioholic Overlord
Thanks for the direction. I am only on my iPhone but it reads like you have achieved some really good results.

I’ve got REW, a UMIK, a 2x4 miniDSP and have some experience with fiddling (including Dirac) but am by no means an expert.

I am thinking that I might have to reach out to an expert (based in the U.K.) as I am just too inefficient when it comes to set up. I like playing around and experimenting but too slow and don’t have enough time in the shared space!
Watch the videos. They will help you quite a bit.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Warlord
I also use three subs in my main system. If your room is symmetrical in any way. I would try and run audyssey with the front two subs as sub one, and the back one as sub number two, without the minidsp etc. you might find it’s pretty good. I also use a minidsp and rew, but guys like @PENG and @Pogre have for a long time said they can get close enough(I’m paraphrasing)without the mini.
What happens when you add subs, is like the law of averages. The more subwoofers you add, the more room modes are excited. That has the tendency create a smoother frequency response, without further EQ. Of course placement is king, so it’s not always that simple, but it’s especially true with corner loading, because even with a single sub, that will basically excite all the room modes at once. LP will be key with a single sub corner loaded, but as you add subs, the averaging will take over making the FR smoother throughout the room.
I see @3db added a video for gain matching subs. While it may have worked for him, I dislike the practice. Imo, if you gain match, the room and placement has to be 100% symmetrical, because when you place the subs in there spots, they’ll be affected by their placement. IOW, if you set the gain on each sub in the center of the room, and then put them into their locations, individual output levels can change. Simply because of their locations. (Level matching VS gain matching conversions are all over the internet if you so choose)
So imo, level matching(with subs in their place) makes more sense, since your setting their output based on where they will be used, and how they’ll be affected by the room accordingly.
If you’re inclined to use rew and the minidsp with Audyssey, you can also get excellent results. The fact is you might have to experiment to find the best results. Again, I use three subs as well, with a mini and rew. Looks like this.

This is before I apply the house curve.
 
3db

3db

Audioholic Overlord
I also use three subs in my main system. If your room is symmetrical in any way. I would try and run audyssey with the front two subs as sub one, and the back one as sub number two, without the minidsp etc. you might find it’s pretty good. I also use a minidsp and rew, but guys like @PENG and @Pogre have for a long time said they can get close enough(I’m paraphrasing)without the mini.
What happens when you add subs, is like the law of averages. The more subwoofers you add, the more room modes are excited. That has the tendency create a smoother frequency response, without further EQ. Of course placement is king, so it’s not always that simple, but it’s especially true with corner loading, because even with a single sub, that will basically excite all the room modes at once. LP will be key with a single sub corner loaded, but as you add subs, the averaging will take over making the FR smoother throughout the room.
I see @3db added a video for gain matching subs. While it may have worked for him, I dislike the practice. Imo, if you gain match, the room and placement has to be 100% symmetrical, because when you place the subs in there spots, they’ll be affected by their placement. IOW, if you set the gain on each sub in the center of the room, and then put them into their locations, individual output levels can change. Simply because of their locations. (Level matching VS gain matching conversions are all over the internet if you so choose)
So imo, level matching(with subs in their place) makes more sense, since your setting their output based on where they will be used, and how they’ll be affected by the room accordingly.
If you’re inclined to use rew and the minidsp with Audyssey, you can also get excellent results. The fact is you might have to experiment to find the best results. Again, I use three subs as well, with a mini and rew. Looks like this.

This is before I apply the house curve.
Gain matching just ensures all the subs are working at the same output and that no one sub is going to be overdriven which can happen if you level match. My greatroom is the antithesis of symmetrical. Its anything but. Look at my sub placements in the greatroom. It speaks volumes as to how unsymmetrical my room is and yet, I managed a pretty decent response across all three listening positions. I also measured each sub's response in their location to see how it responds in the listening area. Thats why they are placed where they are. I also gain matched by subs in my main system as well.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Warlord
Gain matching just ensures all the subs are working at the same output and that no one sub is going to be overdriven which can happen if you level match. My greatroom is the antithesis of symmetrical. Its anything but. Look at my sub placements in the greatroom. It speaks volumes as to how unsymmetrical my room is and yet, I managed a pretty decent response across all three listening positions. I also measured each sub's response in their location to see how it responds in the listening area. Thats why they are placed where they are. I also gain matched by subs in my main system as well.
Like I said, it may very well have worked for you, and it seems it has. I’m curious if the output changed when you measured them in their spots VS when you gain matched them in the center of the room(or driveway or wherever had no room boundaries to affect output).
My thoughts are that when the room is asymmetrical, sub placement will effect their output much more making gain matching problematic. Meaning that, if you set the output of each sub based on a central room location where there aren’t any boundaries to affect output, when you put them in place, the boundaries will change the output levels shifting the DB levels to the sub with better room gain basically, making that sub louder. This would be accented in an asymmetrical room imo.

I can identify with asymmetrical, and actually I think it’s an advantage when it comes to subwoofers. An example would be, my left front sub is under a 10’ ceiling, my right front sub is under a 12’ ceiling and the rear left sub is under a 9’ ceiling.(my listening room ceiling is vaulted from left to right, peaking on the right side where it slants down into the kitchen) The right side opens to a kitchen/dining room.(can share some pics if you want)but does have a bank of cabinets separating the space , and the living room is sunken one foot. Which is why the rear left sub has one foot less airspace above it.
Again, it seems gain matching worked for you, and I appreciate the principle for which you used it.
I just find that level matching makes more sense, since you’re measuring the output while they’re in place, influenced by the room boundaries that affect the subs where they actually are. If you reference the graph I shared, you can see level matching has been effective for me, and my room. More than one way to skin a cat as they say. No, I’d never. My cat is much too handsome with his fur!
 
3db

3db

Audioholic Overlord
Like I said, it may very well have worked for you, and it seems it has. I’m curious if the output changed when you measured them in their spots VS when you gain matched them in the center of the room(or driveway or wherever had no room boundaries to affect output).
My thoughts are that when the room is asymmetrical, sub placement will effect their output much more making gain matching problematic. Meaning that, if you set the output of each sub based on a central room location where there aren’t any boundaries to affect output, when you put them in place, the boundaries will change the output levels shifting the DB levels to the sub with better room gain basically, making that sub louder. This would be accented in an asymmetrical room imo.

I can identify with asymmetrical, and actually I think it’s an advantage when it comes to subwoofers. An example would be, my left front sub is under a 10’ ceiling, my right front sub is under a 12’ ceiling and the rear left sub is under a 9’ ceiling.(my listening room ceiling is vaulted from left to right, peaking on the right side where it slants down into the kitchen) The right side opens to a kitchen/dining room.(can share some pics if you want)but does have a bank of cabinets separating the space , and the living room is sunken one foot. Which is why the rear left sub has one foot less airspace above it.
Again, it seems gain matching worked for you, and I appreciate the principle for which you used it.
I just find that level matching makes more sense, since you’re measuring the output while they’re in place, influenced by the room boundaries that affect the subs where they actually are. If you reference the graph I shared, you can see level matching has been effective for me, and my room. More than one way to skin a cat as they say. No, I’d never. My cat is much too handsome with his fur!
Hey Will, Just making sure we're talking the same lingo. Gain matching is making sure that I measured the same SPL from one sub to another using REW. The subs were all gain matched in one of the positions in the room that one of the subs would occupy. Its late and I'll dig up the independent sub measurements for each of the locations tomorrow. Cheers
 
William Lemmerhirt

William Lemmerhirt

Audioholic Warlord
Hey 3db. The practice I was referring to as gain matching is different I guess. It involves taking each sub to the center of the room and measuring their output at like one inch away. The idea being that the room is taken out of the equation, and as you say it keeps one sub from being overdriven . Imo it only works with identical subs in symmetrical rooms, especially when bass is all about the room.
It seemed odd that you posted a gain matching video but described something else when setting up yours. It seems to me you did in fact level match, not gain match. I didn’t watch the video though, so I could have just screwed that up. Lol.
Late here now too….
Cheers indeed.
 
3db

3db

Audioholic Overlord
Hey 3db. The practice I was referring to as gain matching is different I guess. It involves taking each sub to the center of the room and measuring their output at like one inch away. The idea being that the room is taken out of the equation, and as you say it keeps one sub from being overdriven . Imo it only works with identical subs in symmetrical rooms, especially when bass is all about the room.
It seemed odd that you posted a gain matching video but described something else when setting up yours. It seems to me you did in fact level match, not gain match. I didn’t watch the video though, so I could have just screwed that up. Lol.
Late here now too….
Cheers indeed.
The worst arguements to be had in life is argueing over the same thing with the other person and not realising it. You don't want to know how many times I've done that. :rolleyes: :p

Here are the individual matched sub responses
Individual Sub Response at LLP.jpgIndividual Sub Response at RLP.jpgIndividual Sub Responses at CLP.jpg

Here are the combined sub response pre miniDSP across 3 LP
Combined Sub Response across 3 LP pre Mini EQ.jpg

After MiniDSP across 3 LP (Listener Position)
Combined Sub Response post EQ across 3 LP.jpg

When you look at the graphs, the right LP is closer to the back wall and you can tell from the response regardless of individual, combined, or post EQ. The CLP is the most even and the LLP is the weakest because its closet to the open hallway and stairwell. Its the best I could do with 3 subs in that room.
 
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