# Two Rythmik F12's vs. one F15 and one F12



## Snoop (Dec 29, 2011)

Would sound be better with two Rythmik F12's or one F15 and one F12 subwoofer in a large room open to kitchen and dining rooms?


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## jackfish (Dec 27, 2006)

Depends. The F15 can output bass at marginally more SPL. How big is the room, l x w x h?


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## fusseli (May 1, 2007)

The amps looks the same, so all other things aside the 15 would get a couple dB louder assuming a slightly higher sensitiivity for the larger driver. Why not just go with two F15s? 

Do you plan on placing the subs right next to eachother or spread apart?


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## Snoop (Dec 29, 2011)

Room is 16x21x10 to 11 ceiling. Wife doesn't want two large subs so I may try to sell her on an extra small one. I was leaning toward one F15HP but think with room having several openings, two may sound better.


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## jackfish (Dec 27, 2006)

Two F12s will be more than enough for that room.


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## Nuance (Nov 2, 2008)

At 3696 cu. ft. I'd get two F15's or two F12's.


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## tesseract (Aug 9, 2010)

Snoop, what is your intended usage? Music, movies, both?

For an open floor plan, I recommend looking at the vented FV15 or FV15HP. Yes, they are big.


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## Snoop (Dec 29, 2011)

I listen to more music than movies, so I want the sealed version. For movies, I'm more interested in good music than explosions.


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## tesseract (Aug 9, 2010)

I do prefer sealed over ported myself, overall, but my preference does depend highly upon the application.

Sealed subs depend upon room gain (pressure vessel) for low frequency extension, the type of gain that sealed rooms provide.

Ported subs create their own gain with port tuning and lend themselves well to large, open floor plan rooms.

I use a pair of sealed subs in my small open floor plan room, with extension to 16 Hz. This is not typical, but it can be done. I am thinking seriously about switching to a ported design using the same drivers, which will give me around 9 dB more output @ 20 Hz outdoors, ground plane. I could also realize more output down low by adding another pair of sealed subs, which is more of a hassle. 

I am 99% music with the occasional movie. Then again, I am a bit of a bass nut. :dumbcrazy:

A friend brought his single sealed Rythmik DIY F15 to my home. My opinion is that it is a really nice sub, clean with no overhang. But four of them are needed to pressurize a medium to large size room properly.

In short, it would take four sealed subs to do the same job as two ported in an open floor plan room.


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## jackfish (Dec 27, 2006)

jackfish said:


> Two F12s will be more than enough for that room.


Two F12s will be more than enough for that room.

Sorry, I said that already.


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## tesseract (Aug 9, 2010)

jackfish said:


> Two F12s will be more than enough for that room.
> 
> Sorry, I said that already.


Sorry, but they may or may not be enough. I'd say two F15's minimum. Also, we need to take into account the mains.

Snoop, I should have asked this earlier, what are your mains?


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## Snoop (Dec 29, 2011)

I have Ascend Sierra-1 L/R/C, CBM-170SE Rears. 

My preferred sub is either one F15 or one F15HP. Dave at Ascend and Brian at Rythmik think the F15HP will work, but I guess I have read too many positive posts about the benefits of multiple subs so I want to discuss all options. My 16'x21'x10+' living room opens to kitchen & dining rooms with 6', 2.5' and 3.5' wide open doorways and a 2.5' hallway opening. If there are nulls and I decide I need two subs, I don't want to build a second F15 because of WAF or a second F15HP because of WAF/cost/power consumption. If I need two I would prefer to build two F12's or one F12 and one F15.

I see my options as follow:
- Build F15HP and add F12 if there are too many nulls
- Build F15HP and sell it and replace with two F12's if needed (too much enclosure building and I'm not sure I could get my money out of the F15HP)
- Build F15 and add F12 if needed
- Build two F12's to begin with and live with them
- Sell my wife on two F15's, which is the least likely option

If I go with F15's or F15HPs, I will build enclosures a little larger than those Rythmik sells (3.5CF vs. 3.0CF), so I will get a little more output than their stock models.


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## ALMFamily (Oct 19, 2011)

Whew - I was reading through the options Snoop, got to the last one and it started "sell my wife" and I was like :yikes:.

One question here - is there any benefit to using a combination of ported / sealed subs or will that just create an accoustical nightmare?


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## jackfish (Dec 27, 2006)

> Sorry, but they may or may not be enough. I'd say two F15's minimum. Also, we need to take into account the mains.


OK, you know best. I've got a similar room and can't imagine how two F12s would not supply an accurate reproduction of music bass program material when one seems to do so. There is bass which faithfully captures the engineer's intent, and then there is exaggerated bass to satisfy one's need for more bass as a preference.


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## Snoop (Dec 29, 2011)

ALMFamily, I figured I would get the normal used car salesman response to "sell my wife" of "Don't you wear the pants in your family?" Last time I heard that I said, "either you have never been married or are divorced." I control the garage, she does the rest of the house.

After my last post I read a couple different posts, including one by Big Daddy on the blu-ray forum, that says, "If using multiple subwoofers, you must use identical subwoofers. Different models, even from the same manufacturer, may cause uneven response." So I suppose I need to go with two F12's, two F15's or one F15HP.

Here is a link to that post: http://forum.blu-ray.com/subwoofers...-i-characteristics-placement-adjustments.html


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## ALMFamily (Oct 19, 2011)

Snoop said:


> ALMFamily, I figured I would get the normal used car salesman response to "sell my wife" of "Don't you wear the pants in your family?" Last time I heard that I said, "either you have never been married or are divorced." I control the garage, she does the rest of the house.


I understand completely - I chuckle a bit when I read some of those types of responses and think "rookie". :bigsmile:



Snoop said:


> After my last post I read a couple different posts, including one by Big Daddy on the blu-ray forum, that says, "If using multiple subwoofers, you must use identical subwoofers. Different models, even from the same manufacturer, may cause uneven response." So I suppose I need to go with two F12's, two F15's or one F15HP.
> 
> Here is a link to that post: http://forum.blu-ray.com/subwoofers...-i-characteristics-placement-adjustments.html


Thanks for the link - I had heard that stated before, but I was not sure if it applied to the porting/sealed criteria. Cheers!


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## tesseract (Aug 9, 2010)

jackfish said:


> OK, you know best. I've got a similar room and can't imagine how two F12s would not supply an accurate reproduction of music bass program material when one seems to do so. There is bass which faithfully captures the engineer's intent, and then there is exaggerated bass to satisfy one's need for more bass as a preference.


You are making absolute statements, I am not. You will never know the engineer's intent unless you are the engineer, or present during the mix/mastering. Although room response measurements do help guide the process of accurate reproduction in the home.

At a recent sub shootout GTG I attended, the F15 was lost in the room, participants said it was barely noticed. I arrived late and did not get to hear it, the owner was kind enough to bring it to my house. It did an admirable job, but I feel at least two of them would be needed to fully pressurize the 12X16X8 open floor plan room. He agreed and plans to build another one someday.

Jackfish, while you may feel that one or two F12's are enough, I propose that too much is never a problem, you simply turn it down. It is better to have it and not need it than to be left wanting.


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## jackfish (Dec 27, 2006)

Then overkill for all, Thank You!


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## tesseract (Aug 9, 2010)

You could very well be correct, two F12's may be able to fill the space. It might be Snoop's best option if his wife doesn't warm up to two F15's in the room. Dual F12's would be preferable to one F15.

I don't believe dual F15's would be overkill. It allows for less distortion, as the system wouldn't need to work as hard.


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