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Discussion Starter · #1 ·
Monday there will be a brand new Ftw21 sitting on my door step and this seems like a good time to ask a few thing's.

First is at what point have you just ported a subwoofer just too low? I don't want to run a high pass filter if it can be avoided and I understand that there is a trade off of output for going low but is there anything else that you lose in the deal?

I looked at 30cf sonotube ported to 12HZ will that allow me to avoid the hpf or at that tune am I still going to be stuck with one. The amp I have is a cv-5000 which if I recall will do around 1800 watts into 4 ohms and not too sure but maybe fairly flat to 10hz maybe lower.

My wife told me I can place 2 of these subs into our front room and I have tried to tell her how large they will be but she said she does not care about that as she will be using them as well and they will be behind the couch until the basement room that is built some day.

Anything else I need to know before I start this quest or will this work fairly well and with gain from a second driver down the road make up from the loss of 12HZ.

Thanks.
 

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Discussion Starter · #3 ·
I want to avoid the hpf because of what it does to the signal phase plus the extra delay.

I am using a Onkyo prsc5508 so I should not need a extra eq.
 

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Discussion Starter · #4 ·
As of now I don't have anything to use for hpf I could buy or build something but I would like to try it first without.

The issue comes when I find that one movie that drops to 3hz and eats my driver. I normally watch at -10 from reference but boost the bass. With this setup going from sealed to ported I may not feel the need to run boost.
 

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Discussion Starter · #9 ·
Well HPF it is then. On a other note however how low to port this baby as my wife said do what I want.

With the amount of content below 20hz where is a good compromise between spl and that low port number?

My current setup is a pair of Craig sub 18.1ss that wile I like have never really gave me what I wanted out of them.

With a 12HZ tune and 1200 watts the Ftw will output more below 40HZ then the pair of Craig subs and if I do add a second one it should be able to kill the old setup. On the other hand if I raise the port tune I will get more output from one this is hard.

Does anyone think the content I will be cutting out by going higher will be missed?
 

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Discussion Starter · #11 ·
I have and can't decide. I don't really care about size I am more likely going to be at 30cf tube that if my wife complains can be used to hide inside from her. The output is what I am thinking about and I do know there is content below even 15HZ it's just how much can I get too with a reasonable amount of drivers and avoid my wife filing paperwork to leave at the same time.

I know 2 will be fine and the cost is not too great overall at 3M distance it will give me 115db output at 12HZ and above and that is without any room gain. My current setup at 12HZ is around 90db so if get a pair of the Ftw I should be very happy.
 

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Discussion Starter · #13 ·
That was kind of my thoughts as well. I so want to get this started but I still need to get some 30" diameter sonotube and we'll the wood but the sub is oh so close.

This is my first build ever at least as far as speaker type of project. I know it needs to be air tight. The port is going to be somewhere between 8 to 10 inches which should keep the port speed down. For the port it's self I am going to use sonotube as well.

Anything else I need to think about?
 

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Discussion Starter · #15 ·
I have seen this driver used in this way so it will work but I understand where your coming from with that. It models ok down to that point but if I understand correctly the lower you drop below fs the more over all spl you lose.

From a 16HZ tune to a 12HZ you lose like 6 db so the cost is great but I have around 6 dB of room gain starting around 25HZ so it would work out nicely.

And we'll if it does not I can cut it down and go sealed.
 

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Discussion Starter · #18 ·
It will be some time until I get a box built but here is the sub.

Loudspeaker Subwoofer Audio equipment Drink Computer speaker


That is a 2 L bottle to give you a idea on scale.
 

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Discussion Starter · #20 ·
I seen that thread a wile ago it did look nice. The sonotube is the thing I am having issue finding. Once I find that I can finish this in a few days.
 

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Discussion Starter · #24 ·
I stay under the xmax modeled at 1800 watts of power with a hpf set to 10hz. So I should he fine there and at 2.5 meters will have 108 db at 12HZ and 115 from 20hz and up. If I recall correctly.

Bass shakers are going to be added at some point too just not yet. Being a all cement room the room gain is nice too but not counted on in the numbers. My wife said I can add a second sub as well so a crushed lung should come any day.
 

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Discussion Starter · #26 ·
Thanks. I have the tube and all the parts now just waiting on a friend to cut the wood to be cut for me and it will be done.

Here is a pic of the 30 inch sonotube forced into a PA cruiser.



Vehicle Car Motor vehicle Vehicle door Chrysler pt cruiser
 

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Discussion Starter · #28 ·
Let's just say this. I have to drive 45 miles with the hatch open as that is as much that would fit.

The part that was the worse was trying to get it out on my own. Took 1 1/2 hours to force it out because of how tight the fit was. My wife sat inside and laughed at me in the cold.

I am so close to bring able to complete this build but I need that wood cut.
 

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Discussion Starter · #35 ·
Well she told me I can order a second driver if I want so she can't be too unhappy about it. Not sure where I would install a second one however.

2 would be best as I can spread the drivers out and even out the sound. But first I need to complete this one and see how it turns out.

The final design will be 26.5 cf tuned to 12HZ
 

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Discussion Starter · #37 ·
I want 4 of them one for each corner. That is if I ever start my build in the basement. Or maybe 2 midway on the side walls and a pair in the front corners would be nice.
 

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Discussion Starter · #40 ·
Oh I will trust me on that. It should sound nice I went with a 10" port and model based on 1800 watts of power and the air speeds should be fine.

That is 50% over the 1200 watts the driver is set to handle and it should come out well sense I looked at worse case scenario.
 
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