Add a Sealed Sub Behind/rear of couch?

K

Kleinst

Senior Audioholic
Purists will not approve of this setup. In my TV room I have dual klipsch 115Sw that are behind my entertainment Center. Those are good and similar to SVS pb2000 in my experience.

Then about 4 feet from my couch to the left I have a sealed Martin Logan dynamo sub. I added it because it provides some decent near field bass and the size of those subs is acceptable out in the open. If you have seen them they are down firing black subs that are small and fairly acceptable looking for the wife. Ported not an option out there.

Im considering adding another smaller sealed sub behind the couch to the right for more balance in the room. I’m not lacking for bass per se but think the bass could be a bit more balanced and wonder what adding a dimension behind the listening position would sounds/feel like.

However I know I’m violating mixing sealed and non sealed. I don’t know what problems or cancellations I’m creating. Would you add the extra sealed sub to the rear of the room? (ported not an option there.. too big). Or leave As Is as I might not notice enough difference and could do more harm than good.

welcome thoughts
 
T

Tachead7075

Audioholic
Personally, I would invest in a measurement microphone(MiniDSP UMIK-1), learn how to use REW software(Room Equalization Wizard), and optimize placement and phase interaction on all of your subs and speakers first before buying anything else.

Without knowing what is going on in your room you could make things worse even. Even currently, one of your subs could be cancelling out parts of the others frequencies(this is likely). Setup is one of the most important parts(if not most important) of making a sound system sound good. Even with the best hardware in the world a system could still sound like crap if not setup properly. A mic, REW, and a lot of learning and experimentation is the best way to do this...

Sent from my SM-N975W using Tapatalk
 
mazersteven

mazersteven

Audioholic Warlord
One Klipsch sub should be in the front corner one should be next to or behind your couch and then you can place the other one wherever you like in the room

Should be no reason for a 4th sub
 
KEW

KEW

Audioholic Overlord
Have you tried moving your Dynamo to the proposed location behind the couch to see how that position sounds?
It may not gain anything, but is free to try and always a chance that it will give a decisive "yes" or "no" to putting a sub there!

BTW, if I had to set up a system with no feedback (no ability to listen and judge sound quality), I would apply the rule of not mixing sealed and ported (which primarily applies to using RoomEQ effectively)! But if you already have the subs and can test it out, I know of no reason to categorically avoid mixing ported and sealed subs!
 
K

Kleinst

Senior Audioholic
Thanks very much for your replies. I like the idea of moving my dynamo to the rear space to see what it sounds like.

I also like the idea of buying a microphone and trying to learn REW. However I’m not sure If that comes easily or not. But it’s worth a shot and perhaps beginning of a long process.

Regrettably locations are fairly limited so stuck there a bit. But I guess at least I can still
Make adjustments at those locations
 
lovinthehd

lovinthehd

Audioholic Jedi
REW is a bit of a learning curve but there's a lot of guidance out there if you look for it and spend some time with it. Keep in mind it is primarily a measurement system, altho it can recommend/implement some equalization if you have the right hardware (like a minidsp 2x4 between your avr and subs).

Limited sub locations, just take some time to determine what combo works best in your room (and this is where the measuring comes in).

Generally I prefer to use the same sub, or at least similar subs, in multi sub situations. I do use in my main setup a sub right behind my seat for a bit extra tactile effect. Another way to get tactile effect that I've done is install a tactile transducer under my main seat....
 
K

Kleinst

Senior Audioholic
REW is a bit of a learning curve but there's a lot of guidance out there if you look for it and spend some time with it. Keep in mind it is primarily a measurement system, altho it can recommend/implement some equalization if you have the right hardware (like a minidsp 2x4 between your avr and subs).

Limited sub locations, just take some time to determine what combo works best in your room (and this is where the measuring comes in).

Generally I prefer to use the same sub, or at least similar subs, in multi sub situations. I do use in my main setup a sub right behind my seat for a bit extra tactile effect. Another way to get tactile effect that I've done is install a tactile transducer under my main seat....
Thanks, how does your near field sub compare to your main subs in your setup? Is it smaller but nearer :) therefore still contributes?
 
lovinthehd

lovinthehd

Audioholic Jedi
Thanks, how does your near field sub compare to your main subs in your setup? Is it smaller but nearer :) therefore still contributes?
It is not a small sub :) and is equivalent to the other subs (3 are same, one is slightly different but performs similarly....at least until I finally get around to building the last one then they'll all at least have the same driver, but the last one will be dual-opposed). It's there right behind my seat for tactile effect primarily.
 
K

Kleinst

Senior Audioholic
It is not a small sub :) and is equivalent to the other subs (3 are same, one is slightly different but performs similarly....at least until I finally get around to building the last one then they'll all at least have the same driver, but the last one will be dual-opposed). It's there right behind my seat for tactile effect primarily.
Nice! Sounds like a great setup
 
Pogre

Pogre

Audioholic Slumlord
I 2nd getting some measurement gear and familiarizing with REW. Mixing and matching different subs can get messy fast. It takes some effort and know how to pull it off successfully. The gear would be cheaper than another sub and you just might be able to make big improvements. It's helped me a lot.
 
K

Kleinst

Senior Audioholic
Thanks, I did do one experiment tonight. I don’t have the REW software and Mic yet but I do have a SPL meter and it was interesting. The subs I have in place are two klipsch 115sw that are stacked ‘double decker style’. I’m happy with that by the way. Then the dynamo 1500x that is to the left. It’s a sealed sub but robust 15 inches. Then I was able to wire the smaller Dynamo to the spot I mentioned behind the couch. I played the intro scenes to the first episode of Carnival Row from Amazon Prime which is one of my go to’s for bass. Those of you with impressive setups please try that one , turn it up, and report back. Anyways the SPL was higher when the smaller Dynamo was off. So while it did seem to balance the sound a bit as I felt some bass from behind me, I’m feeling that it’s not a good spot at least with that sub and perhaps even the more powerful Dynamo 1000 I had in mind. I guess sometimes less is more? Hard concept for us to accept. :) I’m not giving up totally but backing off and I might just need to further dial in what I have which is good to me even as is.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Overlord
Thanks, I did do one experiment tonight. I don’t have the REW software and Mic yet but I do have a SPL meter and it was interesting. The subs I have in place are two klipsch 115sw that are stacked ‘double decker style’. I’m happy with that by the way. Then the dynamo 1500x that is to the left. It’s a sealed sub but robust 15 inches. Then I was able to wire the smaller Dynamo to the spot I mentioned behind the couch. I played the intro scenes to the first episode of Carnival Row from Amazon Prime which is one of my go to’s for bass. Those of you with impressive setups please try that one , turn it up, and report back. Anyways the SPL was higher when the smaller Dynamo was off. So while it did seem to balance the sound a bit as I felt some bass from behind me, I’m feeling that it’s not a good spot at least with that sub and perhaps even the more powerful Dynamo 1000 I had in mind. I guess sometimes less is more? Hard concept for us to accept. :) I’m not giving up totally but backing off and I might just need to further dial in what I have which is good to me even as is.
Pretty sure you just experienced what’s known as cancellation. Try adjusting the phase on the rear sub. It’s very close compared to the others(which I’d recommend separating fwiw) so a phase(time) adjustment will probably fix that.
Play a time at the XO point and adjust the phase knob until you get the most spl. That’s a quick n dirty way to blend the near field/3rd sub.
 
lovinthehd

lovinthehd

Audioholic Jedi
Thanks, I did do one experiment tonight. I don’t have the REW software and Mic yet but I do have a SPL meter and it was interesting. The subs I have in place are two klipsch 115sw that are stacked ‘double decker style’. I’m happy with that by the way. Then the dynamo 1500x that is to the left. It’s a sealed sub but robust 15 inches. Then I was able to wire the smaller Dynamo to the spot I mentioned behind the couch. I played the intro scenes to the first episode of Carnival Row from Amazon Prime which is one of my go to’s for bass. Those of you with impressive setups please try that one , turn it up, and report back. Anyways the SPL was higher when the smaller Dynamo was off. So while it did seem to balance the sound a bit as I felt some bass from behind me, I’m feeling that it’s not a good spot at least with that sub and perhaps even the more powerful Dynamo 1000 I had in mind. I guess sometimes less is more? Hard concept for us to accept. :) I’m not giving up totally but backing off and I might just need to further dial in what I have which is good to me even as is.
You're trying to address other room modes with the stacking or is that simply space limitation? If placed within a quarter wavelength of each other subs have a 3dB advantage (equivalent to doubling the power), altho stacking is certainly getting them as close together as possible. It's not strictly about more, but how the subs are interacting with each other and the room. Maybe try this article for starters https://www.soundandvision.com/content/schroeder-frequency-show-and-tell-part-1
 
K

Kleinst

Senior Audioholic
I 2nd getting some measurement gear and familiarizing with REW. Mixing and matching different subs can get messy fast. It takes some effort and know how to pull it off successfully. The gear would be cheaper than another sub and you just might be able to make big improvements. It's helped me a lot.
Thanks, I’m ordering a mic and will try to use REW Learning curve coming).

with multiple subs is it a given to buy a miniDSP HD or is that potentially not needed?
 
Pogre

Pogre

Audioholic Slumlord
Thanks, I’m ordering a mic and will try to use REW Learning curve coming).

with multiple subs is it a given to buy a miniDSP HD or is that potentially not needed?
I ordered everything together. The MiniDSP 2x4 HD and UMIK mic. You could just start with REW to see where you're at and try positional eq and different settings with your AVR but you definitely have a lot more control with the Mini. It will take some time to learn, but I figured it out so it can't be TOO bad, lol. I managed to get to +/- 3 dB from 200 hz down and +/- 1.5 dB from 115 hz and down.

06-22-20 final fr.jpg
 
K

Kleinst

Senior Audioholic
That looks impressive. sounds like the Mini is a no brainer for multiple subs. I’m hoping it’s worth all the work. Would you say it paid off in a very noticeable way?
 
Pogre

Pogre

Audioholic Slumlord
That looks impressive. sounds like the Mini is a no brainer for multiple subs. I’m hoping it’s worth all the work. Would you say it paid off in a very noticeable way?
For me, yes. For sure. I felt like I got new subs again. I have a couple of room modes that are pretty nasty. Lemme see if I can find a "before"...

FL-FR + Subs Crossover Overlay.jpg


God that's so ugly, lol. The above is with no room correction at all. Audyssey and DEQ are off and the Mini is flat. There are multiple sweeps because I was trying different crossover points to see what would happen. I labeled them all so you can tell which is which.

06-22-20 multeq only.jpg


This is after running Audyssey. I'm actually pretty impressed with what it can accomplish when you know what it had to start with. However, you can still see a fairly wide 5 dB dip between 60 and 90 hz and it's noticeable. That's well within the music range and my bass still sounded thin. It's much better but still kinda all over the target goal of 75 dB.

Then of course as the previous post shows I was able to use the mini to really finish dialing everything in for a nice even response.
 
K

Kleinst

Senior Audioholic
Thanks for sharing. Sounds like it pays to get the miniDSP to ensure performance from mult. Subs. More toys to spend my money on.
 
K

Kleinst

Senior Audioholic
For me, yes. For sure. I felt like I got new subs again. I have a couple of room modes that are pretty nasty. Lemme see if I can find a "before"...

View attachment 39768

God that's so ugly, lol. The above is with no room correction at all. Audyssey and DEQ are off and the Mini is flat. There are multiple sweeps because I was trying different crossover points to see what would happen. I labeled them all so you can tell which is which.

View attachment 39766

This is after running Audyssey. I'm actually pretty impressed with what it can accomplish when you know what it had to start with. However, you can still see a fairly wide 5 dB dip between 60 and 90 hz and it's noticeable. That's well within the music range and my bass still sounded thin. It's much better but still kinda all over the target goal of 75 dB.

Then of course as the previous post shows I was able to use the mini to really finish dialing everything in for a nice even response.
Thanks again, you inspired me to get a mic and miniDSP and for my upstairs system it did make a difference in my subs. Was a fun process as well. Do you use your microphone to measure and alter the other channels in any way or just the bass? Curious if people use it in other ways I should consider. I figure Odyssey or whatever room correction is the primarily tool for non sub channels.
 
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