15 ported or 18 non

[landonspop]

I have the big open LR people speak of here. I have been happy with the use of a single DefTech Super Cube I, so I guess I either don't know what I have been missing or an easily satisfied. I want to lean towards tight bass over boomy. Movies and Music is about 70/30.

Since DIY subs are not available for listening, I will need to get some advice.

I could build these 2 subs in a tv stand for 65" tv facing L-A. I would need a place for my large center. ML 50XT.

Or I could put these under an open type pair of end tables. It could fit somewhere in the 25" cube size here. These would be on each side of couch that is on back wall.

What has more sound, for lack of term, a 15" ported sw or a sealed 18" sealed?
I say 18" sealed because I have read that iss all I can do with an 18" with my dimensions.

Once I figure out what to do, is there a place to find build directions?

Thanks in advance!

 

[rojo]

@landonspop Do you have any drivers in mind? What's your budget for subwoofer drivers? You're planning to build a pair, right?

 

[landonspop]

Yes, I was going to do 1 and use it with my other one. I thought these 2 subs would give me a balance of 2 different types of subs.

I see a particular amp that is discussed a lot. It is a 2 channel. And it seems that maybe 2 brands of woofer are spoken highly of for value.

Was thinking $600, but if another $100 made a huge difference, I would let that stand in the way.

 

[rojo]

Stereo Integrity DS4-18 would be a good choice. Here it is (green line) compared to the Dayton 18" HO (orange line):

The box is based on 25*25*25 inches internal, or 9 cubic feet, minus a couple feet for estimated vent, driver, and bracing displacement -- so, 7 cubic feet. The S.I. is tuned to 17Hz; the Dayton, 19.8. The S.I. is modeled at 1100W, the 4-ohm bridged rating of the Crown XLS-1002; while the Dayton is modeled at 500W, which is nearly its max wattage before reaching its excursion limit around 30Hz.

 

[landonspop]

Would this be ported?

25x25x25 is external.. so 24" interior by 3 would start at 8 cubic ft. And you lose 1 or 2 sq ft with guts?

So if I was going to build this, where do I find plans?

This has also been recommitted. Do you know much about this 1? http://www.pssl.com/!2MyaUcARylImXw...PFwtVrG1VzzFOSuxtngJZ3o-49Lu-Sf4mPxoC31Lw_wcB

 

[rojo]

Would this be ported?

25x25x25 is external.. so 24" interior by 3 would start at 8 cubic ft. And you lose 1 or 2 sq ft with guts?

So if I was going to build this, where do I find plans?

This has also been recommitted. Do you know much about this 1? http://www.pssl.com/!2MyaUcARylImXw...PFwtVrG1VzzFOSuxtngJZ3o-49Lu-Sf4mPxoC31Lw_wcB

Yeah, that was ported. Plans TBD.

The Behringer iNuke is a well-regarded amp for this sort of thing as well.

Could you do external dimensions of 25.5"H * 25.5"W * 29.25"D, adding to the depth of the enclosure? And actually, you should probably plan to add feet or casters to your subs, so that will add to the height (or perhaps detract from available height) as well. Is 25" cube a hard limit for all dimensions? I was thinking you might consider making the subs be your end tables, similar to Argroft's build.

 

[everettT]

you still haven't given cubic feet of the entire open area . if you intend to continue to use your current sub you will need outboard eq to make it work. If your limiting your placement options you will need outboard eq . I'd suggest the Dayton Audio ultimax again with eq. Minidsp and a 1500/2k amp with it will shine and it requires investment in a measurement mic. Diy and plug and play isn't as simple as it seems. I'd ditch the average deftech, sell it and by two of the Daytons. doing large sealed subs require power and eq . Ported properly designed subs will require a more exact amp size and less eq.

I have the big open LR people speak of here. I have been happy with the use of a single DefTech Super Cube I, so I guess I either don't know what I have been missing or an easily satisfied. I want to lean towards tight bass over boomy. Movies and Music is about 70/30.

Since DIY subs are not available for listening, I will need to get some advice.

I could build these 2 subs in a tv stand for 65" tv facing L-A. I would need a place for my large center. ML 50XT.

Or I could put these under an open type pair of end tables. It could fit somewhere in the 25" cube size here. These would be on each side of couch that is on back wall.

What has more sound, for lack of term, a 15" ported sw or a sealed 18" sealed?
I say 18" sealed because I have read that iss all I can do with an 18" with my dimensions.

Once I figure out what to do, is there a place to find build directions?

Thanks in advance!

 

[landonspop]

I only have 20x20x20. I can add to back length if I go a little shorter or make an L shape. I will be getting the Marantz 7010 which has 32XT for controlling 2 subs. Does this help?

LR is 24x22 with open kitchen, dining and entry way adding even more.

 

[rojo]

I only have 20x20x20. I can add to back length if I go a little shorter or make an L shape. I will be getting the Marantz 7010 which has 32XT for controlling 2 subs. Does this help?

LR is 24x22 with open kitchen, dining and entry way adding even more.

It's limited to a 20" cube external now? Ok, I'll figure sumn out when I get to work and get my inbox cleared.

 

[landonspop]

I can do bigger and deeper if I place under tv. Many have said they don't like this setup. I have an entertainment center which is basically 2 towers for equipment. They are connected by a bridge across top and a shelf that can be adjusted above tv. The space below this shelve and between the towers is completely open. It was made for the older rear projections tv's to slide into this space.

I built a 2 layer shelf to hold center channel, 2 dvd changers, one on each side, and the lower shelf holds ps4 and xbox, along with games/dvds. It looks like this without the doors. It is 58" wide and 24" deep. Can go about 28" deep if needed. http://www.sears.com/baxton-studio-...lerId=Sears&prdNo=11&blockNo=11&blockType=G11

The towers are 60" apart.

I would need to keep the sub stable from shaking tv. My plan is to put receiver below center, on 2 different shelves and move the dvd changers to towers.

My new center does not fit, so I am needing to rebuild anyways.

 

[rojo]

I can do bigger and deeper if I place under tv. Many have said they don't like this setup. I have an entertainment center which is basically 2 towers for equipment. They are connected by a bridge across top and a shelf that can be adjusted above tv. The space below this shelve and between the towers is completely open. It was made for the older rear projections tv's to slide into this space.

I built a 2 layer shelf to hold center channel, 2 dvd changers, one on each side, and the lower shelf holds ps4 and xbox, along with games/dvds. It looks like this without the doors. It is 58" wide and 24" deep. Can go about 28" deep if needed. http://www.sears.com/baxton-studio-...lerId=Sears&prdNo=11&blockNo=11&blockType=G11

The towers are 60" apart.

I would need to keep the sub stable from shaking tv. My plan is to put receiver below center, on 2 different shelves and move the dvd changers to towers.

My new center does not fit, so I am needing to rebuild anyways.

You lost me. Are you considering setting the subwoofers front and center within your entertainment center, the center channel on top of the subs, and the television on top of the center? And this is the only place the subs will fit if they're larger than 20"x20"x20"?

Putting both subs together removes the advantage of dual subs in evening out nulls at the listening area. 20x20x20 external gives you 18.5x18.5x17.75 internal (assuming double front baffle), or about 3.5 cubic feet. Account for bracing and vent displacements, and now you net around ~2.75 cubic feet. Here are a few options for that size enclosure:

• Blue: CSS SDX12 (500W)
  
• Orange: Dayton 15" HF (500W)
  
• Yellow: Dayton 15" HO (700W)

I modeled an enclosure for the Dayton 15" HO. It's externally a 20" cube, vented, tuned to ~21.5 Hz, and nets somewhere around 2.75 cubic feet with vent and bracing. I'll attach the SketchUp file. Salt to taste. Response should be reasonably close to the yellow line in the graph above.

Or you could build a prefab knockdown box for simplicity's sake.

• 3ft³ box, and add a couple 3" dia * 27 2/3" L vents to net ~2.75ft³
  
• 4ft³ box already vented, but exceeds your target dimensions.

 

[landonspop]

I am so new, the graph means little to me. I have to take your word.

I was told I could do a 20" sq box with 18's sealed. What would the minimal size box be for sealed 18"?

So what is best..
18" sealed vs 15" ported vs better 15" ported sub?

If I go with 15", can I get closer to the 18" subs we were looking at with better quality 15's? Or does the diameter play the biggest role?

 

[rojo]

I am so new, the graph means little to me. I have to take your word.

I was told I could do a 20" sq box with 18's sealed. What would the minimal size box be for sealed 18"?

So what is best..
18" sealed vs 15" ported vs better 15" ported sub?

If I go with 15", can I get closer to the 18" subs we were looking at with better quality 15's? Or does the diameter play the biggest role?

tl;dr: 15" ported is better than 18" sealed.

Here's an illustration.

• green: 15" Dayton HO, 2.75 cu. ft. vented box tuned to 21.5Hz, 800W
  
• orange: 18" Dayton HO, 3 cu. ft. sealed box, Q of 0.676, 900W

The X axis along the bottom indicates frequency in Hz. The deepest tones are the farthest left. Below 20Hz is considered infrasonics, where tones are perceived more by feeling than by hearing. The Y axis going vertically up the left indicates sound pressure level in decibels. The levels are simulated at 1 meter distance. 110dB is about the loudness of a chainsaw or a rock concert. That graph shows the max output of both speakers, limited by power handling and by the excursion limit of the cone.

You can see that from ~35Hz and higher, both subs are almost equal in output. But from 17Hz to 35Hz, the vented 15 actually has more output than the sealed 18. In this frequency range, properly designed vented subs are always more efficient than a similar driver in a sealed enclosure.

What would the minimal size box be for sealed 18"?

Depends on what tradeoffs you're willing to accept. In the example above, that box is already on the small side for that driver. For sealed subs, I tend to prefer subs designed with a Q closer to 0.5. The lower the Q, the tighter the control. 0.5 is considered critically damp. Higher Q = less responsiveness. I say all that to say, in general, the smaller the box, the higher the Q and the muddier the bass.

 

[everettT]

Again if you do sealed in a larger room you need eq, and something like the linkowitz transform circuit to extend the low end. Ported will give you a more functional build, but requires more knowledge in the design . The Dayton HO will give you slightly more upper bass output, while a eqed Dayton ultimax will give you more low end in most rooms. Diy will be a better bang for the buck, but getting a commercial sub say from Rthymik for 1.1k is a no brainer.

 

[landonspop]

So feet were mentioned before. What hight feet should be under the sub, if any?

If I were to add 1" in any direction, how much would that effect the graph?

http://www.parts-express.com/re-aud...-frame-dvc-subwoofer-driver-4-4-ohm--268-8075

If I spend more, do I get more?

In your diagram, are there 2 front boards? 1/2" or 3/4" wood?

Besides built cube and sub, what else is needed? Are the ports just open holes or do I need more?

 

[rojo]

So feet were mentioned before. What hight feet should be under the sub, if any?

If I were to add 1" in any direction, how much would that effect the graph?

http://www.parts-express.com/re-aud...-frame-dvc-subwoofer-driver-4-4-ohm--268-8075

If I spend more, do I get more?

In your diagram, are there 2 front boards? 1/2" or 3/4" wood?

Besides built cube and sub, what else is needed? Are the ports just open holes or do I need more?

My suggestion to add feet was based on a down-firing design, using the subs as end tables. If the subs are only 20" high I feel safe assuming that you're not going to use the subs as end tables, so I did the SketchUp mock up as front firing. If you do front firing, then feet aren't crucial.

Adding 1" to a dimension would give you ~0.15 - 0.2 cubic feet internal volume. The change in response would not be significant.

That RE Audio sub has a higher resonant frequency (32Hz if I recall correctly), and is more appropriate for car audio.

You might get more if you spend more, but there are different compromises to consider. The Stereo Integrity HST18 is capable of output near 120dB, but it requires a box around 5ft³. The HST12 has flat response down to 20Hz in a box that's only 1.25ft³, but it requires gobs of power to match the output of other 12" subs.

In my diagram, there are two 3/4" front baffles. The driver mounts to the inner baffle. The outer baffle serves to strengthen the box, and to make the driver flush mounted for a cleaner look.

In my Sketch-Up I made the port a 1" x 18.5" slot vent, somewhere around 36 inches long (I can't remember the exact length) to tune the box to match the resonant frequency of the Dayton 15 HO driver. As I mentioned earlier, you might prefer this 3ft³ knock down box, adding your own vents. In that case, the vents would be two 3" PVC pipes with PVC elbows to extend the vents to the needed length of 27 5/8".

 

[lsiberian]

If size and weight isn't a limitation porting is normally the best option, but with high output subs compression distortion vs low port tuning tends to be problematic.

Sealed subs do offer better performance in the upper bass range. They also tend to be more tolerable for others including neighbors and roommates. Pretty much any ported sub with a good slot port design or sealed 18" properly tuned will amaze you. I suggest getting a crown amp instead of iNuke due to fan noise. Even with mods it can get loud.

 

[annunaki]

With the limited experience of the OP I would recommend a single 18" sealed with a knockdown enclosure or prefab. Then he has planned upgrade paths as his level of understanding and knowledge increases.

Compared to what he has today, a sealed 18" will be a massive step forward.

Optional upgrades:
Add a Mini-DSP
Build a custome sealed or
Vented enclosure.

No offense intended to you landonspop.