Recently moved to a house with a finished basement where I've commandeered one section for a home theater setup. It has many issues. A 12" beam running left to right through the middle causing odd reflections, complete with Pillar in the middle holding it up. The 24' deep by 14' wide room is open on one side to a 22' deep by 14' wide room, which is open again to a 14 x 14 room. Its also painted almost white which needs to be redone, and the carpet is white which again fades the screen. Oh and the back wall is a series of four patio doors, so 24' or so of glass..

Here's the one end with Sony 40es projector and 120" screen. The corner on the right is only 2' deep, almost flush with front of the right Triton it opens to another room.



Triton 1's and 2 Klipsch Reference 15" subs R-115SW and a XXL center. Denon 6200 and emotiva xpa-5. All part of a 7.2.4 system. (or is it 7.4.4 if I also use the triton lfe?)

Here is a REW sweep of just the Triton 1's LFE channel.



And now a sweep of the two external subs.



You can see I get a lot of standing waves and nulls.

Combine all 4 subs, 2 internal and 2 external and we get....



Kind of a mess ! Although I believe much of the issue here is just playing with proper timing/delay of the two sets of subs. Audyssey after running puts the Tritons as 7ft farther than the Klipsch so their internal delay must be longer.

Run it through Audyssey XT32 which actually does not bad......



and finally a first go auto eq in REW and sent to a MiniDSP to handle the 4 subs. Only 3 small filters, much more experimenting needed to be done.



Currently all the walls are bare, so as soon as I get up some bookshelves, wall treatments, and some absorption panels on the ceiling it should improve some more. I do get some ringing still in the bass but am unsure how to handle that other than bass traps which I prefer not to do.

I also need to try one more setup with the two subs moved to behind the couch, and then again with one sub under the screen and one behind the couch. And then compare all 3 setups to see which has the best even sound across all the seating, and highest WAF. With the back wall patio doors I cannot put the external subs along the back wall or in the back corners.
Next upgrade I'll replace my surround Polk RTi A9's with a set of GE Triton 3+ or 2's but they might be too big.

I'd like to replace the current component stand with 2 sets of low 2 shelf units, such that the top of the units are 18" and then I can place the Supercenter XXL on it and still be under the screen instead of balanced on a center channel stand like I have. Anyone know of some short units ?

Wow, Jarey!

Great sleuthing on your own. It seems AUDYSSEY XT32 has done some taming of your bass issues.I too have AUDDYSSEY XT 32, and have not had the same luck with getting bass tamed that route. I ended up manually adjusting the bass from front T1's and surround T2's, using SPL meter and playing with sub levels from sub 1 (T1's) and sub2 (surrounds T2's).. no external subs. I agree that trying different locations for your external subs is well worth trying.. room modes can be difficult to tame.

Re trying T2's or T3+'s; as long as you have the physical space for them, their SL is completely adjustable, and the more you use similar speakers with matched voicing, the more the sound envelope just seems to come together.

Re lots of glass (patio doors), I have glass fiber verticals for the glass on one wall (slider plus large window), and they do a great job of damping reflections.

I really like the methodical way you are approaching your SQ issues!

Keep at it.

Happy listening.

Jarery,

Thanks for sharing a pic of your space with us. It looks great! Are there some challenges based on your description, sure, but I'd bet a lot of folks out there that would love to have a space like this. I like the look of the whole setup, including the subs. The copper colored drivers look cool. I bet Fury Road sound awesome with all of those subs! We definitely have another bass head here...

What dB level are the test tones you're supposed to be measuring. It looks like you have some room gain/modes to deal with a little but the dips may not be an issue if it's just that everything else is too high. Should the signal be 75 dB? If the gain is too high, would it make the room modes worse? I think you did a great job taming everything and I'm sure it sounds great. Have you measured the rest of your response curves? My issues are between 100 and 400 Hz. ARC corrects everything below 100 Hz extremely well.

As far as stands, I'd check out salamander designs. They have multiple styles and configurations. Many are at or below the height your looking for. Here is one example:

www.amazon.com/gp/aw/d/B000KI714U/ref=pd...1KN92QJEPF6GXP0TC87Q

Cheers,

T Cobe

Well I only wish I had the space you have in your photo T Cobe !

All great questions in regards to the DB level of the test tones. When the AVR is doing test tones running Audyssey you are correct they are done at 75db. And when manually setting speaker levels with test tones its recommended to be done at 75 db. When I'm doing frequency sweeps using REW, i do them at 85-95 db to ensure I am high enough above the noise floor which in my case is around 50db. So measuring I'm doing at a higher level of 90, room correction is done at 75db.

I don't have any sweeps done full spectrum, 15-20,000 hz yet since I've run Audyssey. I also have issues in the same range you have but the 20-120hz range was my worst so that was first to tackle. I'll post an image when I get a chance to tinker some more.

How do you like the Anthem? I almost purchased one a couple months ago but the lack of being able to reassign amps steered me away.

Jarery,

Thank you, but my space is a bit rough right now. I've been investing in equipment and treatments. Once all of that is in place and rough fitted, it will be time to work on the fit and finish. My biggest complaint is my low ceilings. I only have about 89" from floor to ceiling. Our spaces are similar in many other regards.

I really love my Anthem AVM 60! Honestly, I can't say enough about just how good it is. It made a huge impact on my surround sound experience. It pairs extremely well with my XPA-5 and XPA-1Ls. Coming from an Integra Receiver, the improvement was profound. It was able to completely correct my LFE!

My second set of GIK Acoustics 244 bass traps arrive tomorrow. I should have two sets mounted on my front and side walls near my T1s by Friday morning. I should be able to post some impressions then. So far, the panels alone have not tamed my issues but once in place, I should be able to play with my positioning to achieve some significant improvements.

Cheers,

T Cobe

Update after I got a day to try some alternate setups. The previously posted graphs showed that even with the two Tritons using LFE and 2 external subs, there was needing a lot of EQ by Audyssey to get it towards a flatter response.

So not wanting to rely so much on EQ or room creation, I'm trying to get the best setup based just on sub position prior to room correction. In the previous graphs I have a huge booming peak at 24hz and 48hz.
According to this site padrick.net/LiveSound/CancellationMode.htm that corresponds to a room mode of 23.5' which just happens to be the length of my room. For a cancellation of the peak at 48 I need to place a sub at about 70", which conveniently is the distance from the back wall to a spot behind the couch.

Here is a graph now of my external subs both in front compared to one sub at front wall and one behind couch.
The Purple trace is with one sub nearfield, fairly flat untill after the crossover point.



Putting one sub behind the couch pretty much eliminated the peak at 24 and the null at 28. Doesn't look as nice without seeing the two copper subs on both sides of my components but with one behind the couch it sounds much better.

Then comes the question of do I use the LFE channel on the two Triton Ones, or do I just let the Tritons handle all the redirected bass from the other 9 small speakers and relieve them of the added LFE duties.

Here is a graph of the LFE channel using two subs with and without the tritons



Poor color choice on traces but the higher trace with the dip around 27hz is when using the LFE on the Tritons.
Adding the two Tritons into the LFE mix makes it a little more messy and adds gain especially in the 80hz area, but with two 15" subs I'm not really struggling for bass volume so figure I will get the best sounding rerouted small speaker bass by leaving the LFE off the Tritons.

I then run Audyssey and here is the Left and Right Tritons without LFE before and after Audyssey
Yellow is prior to Audyssey and Green is after Ausyssey. This I'm quite happy with as a result.



And finally, a graph with the 2 external subs, overlaid with the L&R, these are smoothed with 1/6 so look nicer than unsmoothed.



Looks good to me and sounds better than previous. Subs running a little hotter than the Fronts. I also typically turn on Dynamic EQ which adds a house curve and boosts the lower end up a bit.

Still need to add room treatments, such as ceiling absorption panels, and maybe a few on the sides at first reflection point and a larger thicker throw carpet. But I have the bass under control for the most part.

I may still need to do some experimenting with bass traps to see if I can increase the decay rate and improve some of the ringing.