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Discussion Starter #1
That is my question.

for HT only, I want to help the movie experience. I want either 1 sub or 2 if necessary, behind my couch to "Feel" the explosions and bullets etc etc... We do not listen to movies loud, but I am looking for the punch in the chest experience.

My HT room is 14'L x 19'L, I have a 16' couch (leather sectional, without the wedge so it is flat) that runs the length of the back wall. Head distance is about 12' from a 110" screen. I have room to put a sub or 2 subs if necessary along the back wall behind the couch.

I will be running a denon 2809ci as of next week, and to power the sub(s) either plate amps or a ep2500. I am at the beginning of this process and have the necessary woodworking tools and experience to build it. I just can't understand how much is necessary.

Thank you in advance for your replies and input.
 

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Re: How do you know how big of sub to build?

Im not an expert in this section but I will chime in with some thoughts. First of all a smaller driver (12") will move less air but because of it being smaller will move faster and thus give you a tighter response some will say that two drivers are better than one large one as they can move the same amount of air or more and give you a better response. You really need to look at the box design/size as well as the port. these both make or break how it will ultimately preform.
How much space do you have to work with?
 

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Discussion Starter #3
Re: How do you know how big of sub to build?

Well currently a foot or two, I can probably move the couch out so that there is 2 feet depth behind the couch, or I unlimited room if I put them on the outside edges where the end tables are, or at the front of the room under the screen.. Here is a diagram. Thank you for the replies.

 

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Re: How do you know how big of sub to build?

Smaller drivers are not quicker or tighter.
Bigger drivers move more air.
Build the biggest you can or want to fit.

What size of enclosure is doable for you?(or if two, will you colocate?)
 

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Re: How do you know how big of sub to build?

I have no constaints on the enclosures, 2 end table subs kind of interest me, but not if they won't move enough air. Putting them behind the couch so that I feel them would limit me on the enclosures. I have no problem with larger subs sitting out in the front of the room.

So by larger drivers move more air, I should be be looking at 15 or 18 inch drives to get the most "punch", correct?
 

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Re: How do you know how big of sub to build?

"Punch" is usually output in the 50Hz-100Hz zone.
Tuning of the enclosure and the Fs of the driver are what decide this.
A alarger driver for the most part will tend to have a lower Fs.
This means it goes lower louder given everything else is the same.

If you have no space constarints for the most part, what is your total allowable budget?
 

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Re: How do you know how big of sub to build?

Another possibility is to replace your ottoman with a sub, put a cushion on top, and put your feet up on it. Keep in mind you do need to get wires to it in some fashion.

What other equipment do you have or plan, besides the 2809?
 

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Discussion Starter #8
Re: How do you know how big of sub to build?

Hmm, cost as with everything in life, the more you spend the faster you go.

I was looking at the EP2500, so somewhere around $1000, for the sub(s). I know this is a subjective response, but if I built 2 - $300 driver subs and could get the same punch and feel out of a single $500 driver sub, then I would go that route.

The ottoman is staying, good idea though, but I just special ordered it to come with the couch in May 2008, so the couch and ottoman are not replacable.

Other equipment:

I have:

oppo 980HD DVD player
comcast hd box
denon 2809ci - arriving monday according to ups

so for the sub(s) I would do plate amp(s) or ep2500

After the subs, depending on difficulty and how they/it turn out, I would prefer to build the rest of the speakers. If I do not find it enjoyable or the results satisfactory, then I will buy new mains and surrounds.

Thank you for your responses.
 

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Discussion Starter #10
Re: How do you know how big of sub to build?

is it too much? I am not a big fan of loud, like I said earlier, just want to feel that bass.

I am thinking that I just do not have enough experience with subs to know what I am looking for.

Should I just build one and then make a determination if I need a second?
 

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Re: How do you know how big of sub to build?

are you set on building a sub? for the money you have available to spend the SVS PB13 Ultra is a fantastic choice and its one of the best. You will defiantly "feel" it.
 

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Re: How do you know how big of sub to build?

Why not build one sub using the IXL-18 as Mike P. suggested and spend the rest on transducers for the couch?

It won't have that "hit you in the chest" feeling that you are describing, but the amount of base from the IXL-18 and the tactile sensation of the transducers would probably give you the immersion your looking for without being "too loud" as you mentioned.

Wow that was a long sentence.
 

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Discussion Starter #13
Re: How do you know how big of sub to build?

are you set on building a sub? for the money you have available to spend the SVS PB13 Ultra is a fantastic choice and its one of the best. You will defiantly "feel" it.

I would prefer to build it, i get alot of satisfaction from the process.

The specs look like it is a 750w plate amp and a 13" woofer. Can I not build something similiar to that for 1/2 the 1599 price? Thanks again for the replies.
 

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Re: How do you know how big of sub to build?

Why not build one sub using the IXL-18 as Mike P. suggested and spend the rest on transducers for the couch?

It won't have that "hit you in the chest" feeling that you are describing, but the amount of base from the IXL-18 and the tactile sensation of the transducers would probably give you the immersion your looking for without being "too loud" as you mentioned.

Wow that was a long sentence.

I thought about -kickers or similiar but the couch and the ottoman are off limits, per the wife. It was expensive and it is staying in one piece I have been told.

Another good idea though. Thank you.
 

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Re: How do you know how big of sub to build?

I would prefer to build it, i get alot of satisfaction from the process.

The specs look like it is a 750w plate amp and a 13" woofer. Can I not build something similiar to that for 1/2 the 1599 price? Thanks again for the replies.
Probably not if you want to use quality components. It would probably come out a little bit lower but then you have to account for your time as well.
Then again its the satisfaction of building one that also gets a person motivated so dont let me discourage you.
 

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Re: How do you know how big of sub to build?

I thought about -kickers or similiar but the couch and the ottoman are off limits, per the wife. It was expensive and it is staying in one piece I have been told.

Another good idea though. Thank you.
Unfortunately, WAF plays a major role in our hobby decisions. I understand completely.

Probably not if you want to use quality components. It would probably come out a little bit lower but then you have to account for your time as well.
Then again its the satisfaction of building one that also gets a person motivated so dont let me discourage you.
I've a grand total of $662 into my sub build. That was using a EP2500, Rane PE17, MJ-18M and a lot of help from a friend with all the woodworking tools.
 

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Re: How do you know how big of sub to build?

Is the behind the couch location strictly WAF? Or are you thinking of putting it here strictly for impact?

If it's the latter, you could look at building it elsewhere in the room. As your couch is on a wall you'll get tons of impact from relatively small subwoofage. Mike's suggestion is a good one for not a lot of money.

Too bad the buttkickers are off limits. I think they would be your best solution. It doesn't matter how big your subs are, they'll have to be fairly loud to kick you in the chest. Could you build a riser to put the couch on and attach the kickers to that?
 

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Re: How do you know how big of sub to build?

If you wanted some kick in the chest then you will need some heavy bass trapping. When looking for a subwoofer look for one with a high tune and high sensitivity.
 

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Re: How do you know how big of sub to build?

To answer your question, how do you know how big of a sub to build?

It's a matter of knowing how much output you want at what frequencies, how much money you can spend, and how much power you're planning on using.

The bigger the enclosure, the higher the sensitivity at the same frequency, or same sensitivity, but at a lower frequency. That means the bigger the enclosure, the less power you'll need to reach the same output.

The bad news is, as others have pointed out, that slam in the chest is at the upper end of the sub's operating range and the lower end of the main's. So enclosure size and tuning becomes less important than if you were aiming to get more output at lower end of the spectrum <25hz.

What mains are you running?
 
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