[gguy]

I am currently running a pair of NX-Otica’s with triple OB subs, and need to address the lumpy and light bass in my room.  I decided to go with the sub swarm approach over traps, due to my room being constrained by the WAF.  I settled on a pair of Rythmik L12’s, which will be put in the back corners of the room adjacent to the listening seat.  I chose the L12’s primarily because of the small size and cost.

I do have a question regarding the integration of the back subs to the front:  I know the back subs phase needs to be set at 180dg from the front. Should the rear subs also be ran in stereo, or should they both be fed a mono signal?

[S Clark]

So you have two  triple OB subs?  Or 6  12" servo woofers, and your bass is "lumpy and light"?       Your speakers have 6 mid woofers in each, capable of playing into the 70's with good volume.   Is your listening area the Roman Colosseum??  I'd do a lot more experimentation with amp settings and placement before I spent any more $$. 
Oops. You've already bought more servo bass.   Move it around, play with the settings.  You already have enough bass generation to power a small auditorium. 

[Early B.]

I'm all in on your swarm approach -- surround yourself in bass. 

However, you may be sacrificing sound quality with the L12's. The ultimate swarm would be a pair of dual servo subs in the rear.

Yeah, and something's definitely wrong with your settings if you have a "normal" room and you're getting lumpy and light bass. Never heard of triples sounding, "lumpy." Give us more info on your setup.

   

[subsonic1050]

Yes it definitely sounds like you have room issues. Major standing waves going on. Have you tried walking around the room with a bass heavy song and seeing how the bass changes as you move around? I think you are going to have to mess with positioning a lot. Without at least some bass trapping it sounds like your room is going to be very difficult to deal with. You don't by chance have a calibrated microphone and REW do you? It would be interesting to see some sweeps.

[gguy]

So you have two  triple OB subs?  Or 6  12" servo woofers, and your bass is "lumpy and light"?       Your speakers have 6 mid woofers in each, capable of playing into the 70's with good volume.   Is your listening area the Roman Colosseum??

I agree, which is why I went with this setup, but my room is primarily the issue.  Not exactly a Roman colosseum, but far from an ideal listening space.

Yes it definitely sounds like you have room issues. Major standing waves going on. Have you tried walking around the room with a bass heavy song and seeing how the bass changes as you move around?

I did this experiment with my previous setup, which had a pair of SVS SB3000's.  I could never find a "sweet spot", I ended up placing the subs next to the mains with my listening chair 3 feet from the back wall.  This was ok but I never got to a level I expected in terms of impact.

[SoCalWJS]

Have you adjusted the EQ on the Plate Amps? (Not sure which plate amp you have)

Makes a HUGE difference.

[gguy]

Give us more info on your setup.

The room is a 15x12 sunroom with a cathedral ceiling that starts about 8 feet up.  The left side of the room opens up to a large foyer that extends up to the height of the home, this foyer also opens up to the rest of the home which is about 1800 sq.ft.  In terms of room treatment, right now I have a set of PI audio diffusors that get placed on the back wall in the speakers.  Future treatments planned are GIK panels for the ceiling and behind the listening chair.

In terms of gear:

Modwright SWL 9.0 AE Preamp
Modwright KWA 150 SE Amp
Topping D90 DAC w/ Microrendu and Roon
Sl1200 GR turntable and Modwright PH9.0 preamp
Anthem STR Intergrated (recently picked up for experimentation with ARC)

[gguy]

You don't by chance have a calibrated microphone and REW do you? It would be interesting to see some sweeps.

I do, but it has been a bit since I pulled it out.  Below are some recent measurements using ARC, don't mind the target or corrected curve, a it was just experimentation.  The subs were set at the default AVR setting per Rythmik.

[Early B.]

The room is a 15x12 sunroom with a cathedral ceiling that starts about 8 feet up.  The left side of the room opens up to a large foyer that extends up to the height of the home, this foyer also opens up to the rest of the home which is about 1800 sq.ft.

Oh. This explains why you're having bass issues. That's almost impossible to fix. No need to throw more money at it. Nearfield is your new best friend. 

[subsonic1050]

Couple of things - first, as I'm sure you're aware your Otica's are extremely close to your back wall. I don't know if you have the space to pull them out, but I would try that. Also, yes, your sweeps definitely indicate that you have some pretty large room modes - especially on the sub sweeps. Do you have the ability to move the subs around at all? I'd move them around and check with more sweeps - also if you are able to change your listening position that could help as well.

I really don't know what else to tell you. The only way I've been able to tame bass like that is with a HUGE amount of bass trapping. If that's not possible for WAF reasons you're going to have a fight on your hands for sure. You could definitely try additional subs, but you're still likely going to need to play with positioning quite a bit. DSP might be your only real option.

[gguy]

Couple of things - first, as I'm sure you're aware your Otica's are extremely close to your back wall. I don't know if you have the space to pull them out, but I would try that.

I had them moved around, the front baffle is typically 4ft front the back wall, sub baffles are typically 3ft from the back wall.  Placement is definitely an issue, the size of the speakers does not allow much for movement. .

I have moved the seating position back and forth a bit.  I actually preferred the bass when the seat was closer to the back wall (about 1ft) but at the expense of a brighter sound.

It does appear that I have a battle on my hands.  There is actually some flexibility with the WAF as far as placement, but turning the room into recording room is a no go.  The main thing is that it looks good… The treatments I do have, and plan on getting, can be easily take down when not in use (except for the proposed ceiling treatments).

[mlundy57]

Your subs are not dialed in to match the Oticas. The graphs tell me a few things:

The average level of the ‘Oticas is about 75dB and they are -6dB around 69dB which will be the crossover point

The average level of the subs is 65dB with a big spike at 40Hz. This spike is a room mode which you can address with the PEQ adjustments.

The average level of the bass is way to low. It should be between 75 and 78dB depending on if you want the bass balanced with the Oticas or a little hotter. 

The first thing you need to do is, with phase set to 0 and PEQ off, increase the subs volume until the average SPL is between 75 and 78 not counting the 40Hz spike

Adjust the crossover control until the sub is -6 at 69Hz

Turn PEQ on and adjust the PEQ parameters to bring the big peak at 40Hz down to be in line with the overall bass level, or as much as you can, whichever comes first.

Run a sweep with both the Otica and sub playing. They should sum at the crossover point bringing it up in line with the rest of the curve. If the response at the crossover point doesn’t come up like it should, The sub is out of phase with the Otica. Start adjusting the phase control until the crossover point comes up where it should.

[gguy]

Your subs are not dialed in to match the Oticas.

Hi Mike, I think that results I posted were somewhat misleading.  I had the amp plate zeroed out (50% volume, 0 PEQ, 0 Phase, X-over wide open).  This was to let the STR make the adjustments, which ended up being worse than how I originally had it. 

At this point I have decided to start from scratch.  I have the subs out of the room and am working on re-positioning the Otica’s and my seating position.  Once I get the subs back in, I will get some proper combined measurements in REW and go from there.

[DannyBadorine]

I don't want to take the fun out of it for you, but have you tried just using one sub?  The reality with that much low frequency information is that it's bouncing off of all the walls and coming from 4 different places which is going to give you a bunch of phase cancellation.  In a room that size, it's nearly impossible to get that many subs working properly together.  The low end will sound different in every spot.  More subs is rarely the answer.

[sunnydaze]

.......No need to throw more money at it. Nearfield is your new best friend.

Good luck getting all those drivers to integrate!

........ Placement is definitely an issue, the size of the speakers does not allow much for movement. .

Might simply be the case of too large a speaker jammed into too small a room?  See it all the time.

[subsonic1050]

Gguy - you're sure getting a lot of different advice! I think the combination of room treatment (if possible), sub positioning, as well as Mike's instructions for setting your plate amps is likely to yield the best results. I don't have as much experience as a lot of guys on this forum, but what I do have quite a bit of experience with is taming absolutely terrible bass in my room. My listening room is in a basement so it has concrete on 3 sides - talk about standing waves. The room treatments were an absolute necessity, and it required further tweaking from there.

I don't want to take the fun out of it for you, but have you tried just using one sub?  The reality with that much low frequency information is that it's bouncing off of all the walls and coming from 4 different places which is going to give you a bunch of phase cancellation.  In a room that size, it's nearly impossible to get that many subs working properly together.  The low end will sound different in every spot.  More subs is rarely the answer.

Using at least 2 subs is very often at least part of the answer. It is also very common to add more subs in addition to two - which is sort of the minimum for good sound. With only one sub, the bass is emanating from one spot, and getting an even bass response throughout the room is basically impossible. That's why you see virtually everyone on this site building 2 servo subs if money allows. Then the key is positioning those subs in the correct location, and/or adjusting the phase so that the subs end up canceling out major peaks and filling in major nulls to get a relatively even response. He could certainly try just one, but my guess is that it would be worse.

[mick wolfe]

Yes, maybe not the ideal nearfield candidate, but the Otica's are too close to the front wall/window regardless.( this has been mentioned already) I would think 2 subs tops would be more than adequate in that room and set up. In fact, the suggestion mentioned of just trying one sub might be a good starting point. Even before adding any sub, however, I'd try positioning the Otica's so they have more breathing room. You're not getting the full capability of an open baffle design unless they're well away from the front wall. Maybe others that have true experience with this speaker can chime in on a recommended distance.

[EdwardT]

You’re probably going to want to do this in stages, first get Oticas placed where the low end smooths out and isn’t so lumpy, then test sub placement w/o the Oticas until you get a nicer curve and can set the xover point. Then it’s just a matter of rotating the sub phase until you get the best result with your ears. Trust your ears, the test gear won’t be listening to any music

[DannyBadorine]

Gguy - you're sure getting a lot of different advice! I think the combination of room treatment (if possible), sub positioning, as well as Mike's instructions for setting your plate amps is likely to yield the best results. I don't have as much experience as a lot of guys on this forum, but what I do have quite a bit of experience with is taming absolutely terrible bass in my room. My listening room is in a basement so it has concrete on 3 sides - talk about standing waves. The room treatments were an absolute necessity, and it required further tweaking from there.

Using at least 2 subs is very often at least part of the answer. It is also very common to add more subs in addition to two - which is sort of the minimum for good sound. With only one sub, the bass is emanating from one spot, and getting an even bass response throughout the room is basically impossible. That's why you see virtually everyone on this site building 2 servo subs if money allows. Then the key is positioning those subs in the correct location, and/or adjusting the phase so that the subs end up canceling out major peaks and filling in major nulls to get a relatively even response. He could certainly try just one, but my guess is that it would be worse.

Yes and no and maybe......using more than one sub in such a small space will definitely lead to a different response but ultimately there will be more phase cancellation.  2 subs can totally make things better if they interact properly, but it's more than likely only better across some frequencies and worse across others.  With one sub, the bass is emanating from one spot, but its bouncing off of all of the walls to create the whole low frequency spectrum.  Adding another sub also adds all of those reflections from a different spot.  But, if you're save with DSP, delay and EQ then it certainly can make sense.  Plus, you can get lucky and it just might work great in your room from the start.  But the added phase can lead to smearing and a lack of punch in the subs.  Most of my experience is in large musical venues and we are able to get an even low end sound with lots of DSP but then there's less punch.  But if you have a lot of punch, the low end can be 10db louder within a matter of a few feet. 

[S Clark]

Oh. This explains why you're having bass issues. That's almost impossible to fix. No need to throw more money at it. Nearfield is your new best friend.

As others have mentioned, near field isn't a good option with those speakers, and with that room, it looks like there are no good options.  What does the wall opposite the archway look like?