How to build a sub that can go down to 20hz or even 15Hz??

Hi All,

I have 12" drivers with following specs.
FS=25Hz
Qts= 0.41
Vas=86L
Power=200W
Xmax=20mm

Till now i built ported subs with 28Hz F3 with this driver.

But is it possible to build a sub that can go as low as 15Hz or 20Hz with the same driver ?? What kind of enclosure can do the trick ??

Any suggestions please ...
 
It totally depends on the environment it’s going to be in?. (Size of room)

Also totally depends on what dB you are hoping to achieve.

It will hit 15 or 20 but doesn’t mean it will be at the volume level you require.

If I’m honest to get meaningful output at 20hz or below it would need to be ported.

I don’t know how the driver models or if it’s suited to ported or sealed ( don’t know enough about the driver)

But even so 15 and 20hz with 12inch doesn’t go hand in hand. If sealed.

Also the lower the tune the bigger if box if going ported. How big can it be?

For reference I built a sealed Alpine SWR15. 140l sealed enclosure. 1000w going through it.

It does 20hz and even 15 hz with meaning.. but it doesn’t completely blow your socks off..

Don’t get me wrong, things shake and it’s really loud. But it doesn’t kick you in to next week. Hence building a second.

Addictive game my friend.

Oh and I would forget 15hz if going ported. Tune it to 20hz. And try and achieve good output there.I’m not saying your aren’t missing anything. But to appreciate what your missing you would need more drivers and more power. So ide just stick to 20 if it were me.
 
Do you have good reason to think your experience will better if you can go that low? Maybe strong and clean output (and a bit boosted) down to 30 Hz makes for really great sound with any music source you enjoy.

The driver resonance influences how low you can go. No two ways about that. All you need to do is mount the driver in a way that doesn't compromise the low-end reach.

B.
 
since you have 2 of them, why not put them together in a 6th order bandpass? :D
the thin line is the other single driver ported one.
 

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Hi All,

I have 12" drivers with following specs.
FS=25Hz
Qts= 0.41
Vas=86L
Power=200W
Xmax=20mm

Till now i built ported subs with 28Hz F3 with this driver.

But is it possible to build a sub that can go as low as 15Hz or 20Hz with the same driver ?? What kind of enclosure can do the trick ??

Any suggestions please ...


If you have two drivers, ... and want a single enclosure and want to get to say 20 Hz, build
1. a ported enclosure with an EBS (extended bass shelf) alignment ie lower extension at the expense of absolute power handling
2. PPSL for force (and even order harmonic) cancellation .

I'm assuming this is for home theater where you want max extension

As always, run some numbers through WinISD (at the very least) to get an idea of performance and size
 
Last edited:
It totally depends on the environment it’s going to be in?. (Size of room)

Also totally depends on what dB you are hoping to achieve.

It will hit 15 or 20 but doesn’t mean it will be at the volume level you require.

If I’m honest to get meaningful output at 20hz or below it would need to be ported.

I don’t know how the driver models or if it’s suited to ported or sealed ( don’t know enough about the driver)

But even so 15 and 20hz with 12inch doesn’t go hand in hand. If sealed.

Also the lower the tune the bigger if box if going ported. How big can it be?

For reference I built a sealed Alpine SWR15. 140l sealed enclosure. 1000w going through it.

It does 20hz and even 15 hz with meaning.. but it doesn’t completely blow your socks off..

Don’t get me wrong, things shake and it’s really loud. But it doesn’t kick you in to next week. Hence building a second.

Addictive game my friend.

Oh and I would forget 15hz if going ported. Tune it to 20hz. And try and achieve good output there.I’m not saying your aren’t missing anything. But to appreciate what your missing you would need more drivers and more power. So ide just stick to 20 if it were me.

Hi....thanks for the inputs.
Actually when i say 15Hz, I mean that at F3 or atleast at F6.
If it plays 15hz at too lesser volume, it's useless obviously. I never tuned the ported boxes below drivers Fs.

So I am wondering if any different enclosure design can give 15 or 20Hz @ F3.
 
If you have two drivers, ... and want a single enclosure and want to get to say 20 Hz, build
1. a ported enclosure with an EBS (extended bass shelf) alignment ie lower extension at the expense of absolute power handling
2. PPSL for force (and even order harmonic) cancellation .

I'm assuming this is for home theater where you want max extension

As always, run some numbers through WinISD (at the very least) to get an idea of performance and size

Hi Zobsky,

Please see the attached image.
That is a single driver Vs dual driver PORTED subs I built earlier.
I always tuned the subs higher than drivers Fs to minimize group delay etc.

I never tried extended bass shelf earlier. I will check that.
Current requirement is to find an enclosure design that can go below 20hz or 15hz @F3 or F6 with single driver.
 

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Do you have good reason to think your experience will better if you can go that low? Maybe strong and clean output (and a bit boosted) down to 30 Hz makes for really great sound with any music source you enjoy.

The driver resonance influences how low you can go. No two ways about that. All you need to do is mount the driver in a way that doesn't compromise the low-end reach.

B.

Hey Bentoronto,
Dayton Audio RSS315HF-4 is interesting!!
All the subs I made earlier are tuned higher than Drivers Fs.
The bass is clean and quite enjoyable. (Please see the attached graph in my above post)

Now I want to explore the ways to tube the box down to 20 or 15hz with my existing driver (if thats possible at all)
I want to see how it sounds with the same driver. Trying to see if any unusual enclosure design can do the trick.

Thanks for suggesting 6th order bandpass. I will try to simulate. !!

(But what is your observation from your experience? 6th order bandpass gives tight and accurate bass or will it be boomy with less transient response?
 
sorry guys ...the image i attached in post#8 is wrong.
Here is the correct image


So basically 6th order bandpass is one I can try.
Any other enclosure designs that can be tuned very low??
Sonotube will work ?? Or any other ideas??
 

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Since you did not define max tolerated enclosure size and did not specify the driver I granted myself some freedom in those regards.

Here is a large SUB-ROAR212 which pressed up into a corner is a quite capable subwoofer down to 15 Hz.

Max spl is simulated with 20 mm xmax and 400 watts for two 12 inch drivers.
I used Peerless XXLS12 is this simulation.
 

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Also, ensure that the T/S parameters are correct, most often they are not. If xmax is not as much as claimed then it will be a big disappointment.

Hi wonderfulaudio,All

You're correct.Without doing a Consistency Check and an educated guestimated calculation of Driver Sd and Xmax from a Ruler Measurement of the Driver Frame Width and the Rubber Surround Diameter) : The given Data could be way off and sculptured to impress any ignorant Layman.

So What is the Frame Diameter?

b:)
 
Let's slow down a moment and think more what we are proposing. The solutions proposed here are of the sort that add low freq resonators to the driver, kind of like the pumpkins glued to the ends of a sitar.

There's no "free lunch" with that kind of solution. The "price" is resonance that will always be ready to ring whenever it feels tickled and harm transient response and clarity. At super-low freqs, that may be tolerable in a way that would be indigestible to persons careful about their audio in the usual ranges of BRs and THs.

There are music genres, disaster movie buffs, and some music listeners who would find that OK

B.
 
Hi All,

I have 12" drivers with following specs.
FS=25Hz
Qts= 0.41
Vas=86L
Power=200W
Xmax=20mm

Till now i built ported subs with 28Hz F3 with this driver.

But is it possible to build a sub that can go as low as 15Hz or 20Hz with the same driver ?? What kind of enclosure can do the trick ??

Any suggestions please ...

Sealed big boxes put in the corner of a not to big room. If you need more low end you can eq that in until you reach xmax.


Sealing/stuffing the BR ports with a towel might be enough.
 
With closed box, modern dsp and cheap power, we can have the response we like easily, but sdp capacity/distortion easily become a problem. Room gain helps a lot below 30Hz in most rooms, and below 25Hz we hear mostly distortion.

Here a single 10" woofer nearield vs. room response. I recommend at least a sub per main speaker!
 

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