Subs....Worth another build or purchase?

[annunaki]

What is the internal net volume of your existing sub enclosure(s)?

 

[Clownaphobia]

2 cu ft. I took into account sub displacement.
Modeling showed that would give me strong performance along with good protection of the subs at around 600 -1000 watts per

 

[Clownaphobia]

I did a build thread on AVS when I originally built them..I just went back to the thread to make sure of specifications and got a little nostalgia. So had to share a couple pics the last pic is in my current setup

 

[William Lemmerhirt]

Wow man, they look awesome! Nice setup(the couch on the right would drive me nuts though! OCD!!!)

Hope your dad recovers quickly. Sorry to hear of his troubles. I’m thankful for our service men and woman, and respect them very much. I wish the gvmnt would take better care of them.

 

[annunaki]

I was possibly thinking you could repurpose your existing enclosures with an upgraded woofer for a little more output on the lower end.
The one option that comes to mind off the bat is the CSS SDX12. If you added a slight touch of EQ to improve the very low end it would likely give you a boost in performance.
If you could perhaps get a room layout drawn up or sketched it may help us help you more with some options.
Would a “table” behind your sofa be an option? Meaning you could build a furniture quality subwoofer with some dual opposed 15” for example? Or could something like that be added or replace something else in the room?

 

[Clownaphobia]

I’m trying to attach photos but now it’s saying the attached files are to large for the server to process??

 

[Clownaphobia]

Sorry for the late response. I wish I could get the pics to upload!! There is an existing table that runs directly behind my sofa...I considered turning that into a sub. In the meantime, Ive been thinking of setting one of my HsU subs there to see if I get any output/smoothing/ near field benefits. It is the first thing you see when you walk in my house, but I could make it look nice and no one would have any idea that it wasn’t a normal table. I Could def get away with putting a 12” in there. The only thing that worries me is that it will be on a concrete floor with no boundary enforcement (since it’s at least a few feet from any wall). I also have a partial wall that I could put another 12” towards the back of the room. But I should clear up...The bass is not bad as it is. Actually fairly impressive. But quad 12’s can’t be a bad thing. I’m getting over my need for pressurization...it’s not a sealed and dedicated theater room, so as long as I have strong output and clean, deep bass, I will be happy.

 

[annunaki]

Sorry for the late response. I wish I could get the pics to upload!! There is an existing table that runs directly behind my sofa...I considered turning that into a sub. In the meantime, Ive been thinking of setting one of my HsU subs there to see if I get any output/smoothing/ near field benefits. It is the first thing you see when you walk in my house, but I could make it look nice and no one would have any idea that it wasn’t a normal table. I Could def get away with putting a 12” in there. The only thing that worries me is that it will be on a concrete floor with no boundary enforcement (since it’s at least a few feet from any wall). I also have a partial wall that I could put another 12” towards the back of the room. But I should clear up...The bass is not bad as it is. Actually fairly impressive. But quad 12’s can’t be a bad thing. I’m getting over my need for pressurization...it’s not a sealed and dedicated theater room, so as long as I have strong output and clean, deep bass, I will be happy.

If I get a chance I will try and model up the CSS SDX12 in 2ft^3 to give you an idea of what it may be capable of. Then, adding in some Eq you could likely get even better response since the woofer has some nice headroom.

 

[Verdinut]

Thanks a lot guys for the help! It’s actually 10’ ceilings...which makes it worse. I Honestly didn’t realize how much space I was trying to deal with. I guess I will just have to change my expectations. Maybe I’ll be one of those guys who tells everyone that I’m more focused on clarity of the overall system rather than output new self proclaimed audiophile! That, or man up and build about 4 ported 18’s!

If you want to enjoy the higher efficiency of the ported system as well as moderate box size, it's more expensive but you could use two UM-18 operating in an isobaric configuration. You could reduce the cabinet volume by 50%.

I would also suggest that you use Baltic birch plywood which is the best material for subwoofer boxes as its resonance is higher than that of MDF. Other advantages are that this plywood is a lot sturdier and weighs a little less.

 

[Clownaphobia]

I noticed PE has an Ultimax 18” kit with passive radiators. Has anyone heard anything about it? That’s an option

 

[Verdinut]

I noticed PE has an Ultimax 18” kit with passive radiators. Has anyone heard anything about it? That’s an option

Although PR designs permit use of smaller cabinet volumes, according to Vance Dickason, in his Loudspeaker Design Cookbook, PRs have a steeper cut-off, less transient stability, a slightly higher cut-off frequency and greater overall losses (Qt) than vented designs.

 

[annunaki]

Although PR designs permit use of smaller cabinet volumes, according to Vance Dickason, in his Loudspeaker Design Cookbook, PRs have a steeper cut-off, less transient stability, a slightly higher cut-off frequency and greater overall losses (Qt) than vented designs.

All of that is easily accounted for in the design phase mind you. Not to mention, a PR can also be infinitely tunable within its design parameters. The steeper rolloff is generally not an issue for sub woofers since It usually occurs below the audible range.

The huge advantages of PRs is one of space and noise. Proper venting of a large low tuned sub woofer to prevent vent noise can often have a vent that displaces 1-2ft^3 of volume in the enclosure. That is a lot of space! In addition then you also don’t have to worry about the first vent resonance frequency potentially showing up.

 

[annunaki]

I finally got around to modeling the CSSSDX12 in 2ft^3.

It will do fine by itself as it would be considered a critically damped design with a Q of .57 and an F3 of 32.5hz. Solid performance really from a sealed woofer. I am quite confident they would be a step up from what you have.


If you added some parametric Eq you can get the the F3 down to 23.5hz. I won’t get into that unless it is something you think you would pursue.

Just some options is all.

 

[Clownaphobia]

@annunaki thanks very much! I had a chance last night actually to start playing around with my system. My wife just left for the weekend to visit a girlfriend of hers
I recalibrated everything with my RS spl meter. Turns out that Audyssey set my subs about 5 to 6 dB low!
Seems so dumb, but honestly just turning the gain up to -3 in the AVR (about 1 o’clock on the amp) has made an outrageous improvement. I’m still not running them hot...that’s a couple db’s low. I ran some test tones and even get plenty of output down low. Do you think that purchasing a mic and using few and eq would be a better idea? I spoke to a member on the forum that built dual sealed type R 12’s like me...with the idea of swapping them for dual umax 15’s..and he seemed to think that they were actually very close in specs, output, etc, and would be a lateral move. Of course that’s comparing sealed to sealed. If you think that the CSS would be a big improvement I would still definitely consider it?? The Type R modeled very well...but it has been a few years now and I know that technology keeps moving

 

[annunaki]

A 15” sub with similar Xmax will out do a 12” so long as both are in the proper enclosures. There is simply a lot more cone area to move air. In fact, one would need three 12” to be about equal on displacement to dual 15” all else being equal.

15” subs typically have a lot higher volume requirements though. It depends upon what you can live with etc. Audio is all about compromises as there is no free lunch. That is why it is important to know what you like/want to accomplish and just go after it.

If you went with the CSS SDX12 you would get an increase in performance but it will not be as dramatic as moving to Dual 15”. The. advantage is that you keep the enclosures you have now. Additionally, the CSS provides about 33%-50% more xmax than the Alpine (going off memory) in the same footprint.

I am not advocating one way or another. You simply need to think about what you want/need.

 

[Clownaphobia]

Okay guys, sorry for being m.i.a..I’ve been super busy lately. But I really do appreciate the help that you’ve given! Thank You!
So after I’ve been able to spend some time playing experimenting and making adjustments...I feel that I actually have enough output for what I want. HOWEVER...I do need opinions. The subs sound great (especially at certain frequencies) ...but do sound fairly boomy in others. They are at 1/4 positions on the front wall, almost pushed up against the walls.
I did a test and pulled them away from the wall about 2 feet and it immediately cleaned up and tightened up the sound! (Assuming that the bass is getting to much boundary gain), would a mini dsp be able to EQ the peaks that are too boomy and tighten up the sound? Or do I just need to find a way to move them away from the walls? I have zero experience with minidsp...and would need probably need someone to literally walk me through the process if that is what I should do. I have heard great things about it on the forums

 

[ryanosaur]

@Clownaphobia
Have you experimented doing the Subwoofer Crawl? Though crude, it is very effective at helping you understand some of the LF acoustics in your room.
I am somewhat Anti-front wall. Partly due to space issues, but also my corners are horribly boomy and muddy. To me, those placement "instructions" are just dogma and wasted breath. When I did the crawl and heard how the LF characteristics changed as I moved around the room, including finding a dead, it was very... ear opening.
I also am a fan of the Geddes technique for placing multiple subs. Though I have not been able to go deep into measurements, just considering the basic advice of strategic asymmetrical placement really helped in my room. Geddes considers your mains to potentially be LF sources too, so getting those subs away from them can be very helpful!
Hope this helps!

 

[Clownaphobia]

@ryanosaur
Thanks for the response! I have and am a firm believer in it. But in the new house I’m limited to only a couple different options. I have had good experience with front wall, as long as not too close to corners. They currently sit just inside my towers, And definitely make localization nill.
There are two other options...One towards the back wall and one in a nearfiled config begins the couch which would have zero boundary reinforcement (at this point I think that would be the better of the two options). But too be honest..up front where they are now, just moved away from the wall a couple feet, they sound pretty awesome. I just can’t leave them there

 

[ryanosaur]

It might be worth the cost of the experiment putting them, one each, in those two other locations just to see how they perform when tested. Other than the labor... and maybe longer subwoofer cables, It might do what moving them 2' into the room does for you. Just a thought.

 

[lovinthehd]

You can also use the room simulator in REW (Room EQ Wizard) for estimating sub placement. Tutorial on multi subs/minidsp use https://www.minidsp.com/applications/home-theater-tuning/tuning-multiple-subs