HT-PIONEER SUB 15-20Hz with the highest SPL

Hello, first post here. :wave:
I am considering building a sub with a Pioneer TS-W312D4 as the driver for home theater. I cant understand how to build the port or the total enclosure volume through WinISD ; by trying changing values of the tuning frequency it is giving me the proper response in the Transfer Function Magnitude, but I cant figure out what structure needs to be changed to reach the lowest frequency in about 15-20Hz with the highest SPL possible?
 
PS, I should add, in case it's not completely clear from those links, there is a fundamental tradeoff in all speker design that has to be managed, and that is between three characteristics.

Those are: Overall box size, Low Frequency Extension and Maximum Volume.

It's easy to optimise any one of those, as we have both the others to play with so neither of the other characteristics takes too big a hit on its own.

We can optimise any two of them, but then the third has to do all the compromising, so it will suffer.

We cannot optimise all three at once.

This is known as Hoffman's Iron Law.

Further, the parameters of any specific drive unit determine what range of box size, extension and SPL are going to be available to work with, so in general, it's best to work out things like How big a box can I accomodate? How loud do I want to get? and How deep do I want to get? before committing to a specific driver.

Cheers,
David.
 
PS, I should add, in case it's not completely clear from those links, there is a fundamental tradeoff in all speker design that has to be managed, and that is between three characteristics.

Those are: Overall box size, Low Frequency Extension and Maximum Volume.

It's easy to optimise any one of those, as we have both the others to play with so neither of the other characteristics takes too big a hit on its own.

We can optimise any two of them, but then the third has to do all the compromising, so it will suffer.

We cannot optimise all three at once.

This is known as Hoffman's Iron Law.

Further, the parameters of any specific drive unit determine what range of box size, extension and SPL are going to be available to work with, so in general, it's best to work out things like How big a box can I accomodate? How loud do I want to get? and How deep do I want to get? before committing to a specific driver.

Cheers,
David.


Thank you for the explanation David. Box size is not an issue for me. I just want a good SPL at the low ~ 20 Hz for movie watching . Even when I change the port size and numbers is does not affect the frequency response curve?
 
Hmm, pretty sure the links I mentioned should have covered that.

Anyway, the frequency response curve shape is determined by the box volume and tuning frequency, in conjunction with the driver's own parameters.

So, you use the box size & tuning controls on the "Box" tab to get the best combination of size/extension/flatness first.

Then, go to the signal tab and input the voltage that your amp will be able to generate in the "driver input voltage (each)" field (or just the speakers power rating in the "system input power" field, although this is a little less accurate in the real world than converting to voltage first).

Then go to the Cone Excursion graph to check that you aren't trying to push it farther than it can realistically move while still tracking the input signal in a reasonably linear manner.

Then go to the SPL graph to check it gets loud enough.

Then go to the Rear Port - Air Velocity graph and adjust the port dimensions (on the "Vents" tab) to keep velocity low enough - 17ms-1 or lower is ideal for hifi, though in some circumstances a bit higher may be ok. Note that once the box volume & tuning are set, adjusting the port dimensions won't result in any change to the main frequency response graph shape.
 
Changing the port size, length and cabinet volume should all affect the frequency response curve.
That said, the Pioneer TS-W312D4 has an Fs of 38Hz, Vas of 34.1 liters, and an Xmax of 7.7mm, it is not going to produce much output at 15-20 Hz, regardless of the box size or tuning (Fb).
 
indeed, that driver will never go that low loud. You need a special and big subwoofer for that as not many can do that. A cheaper example of one that can is the Dayton UM18-22 that can do that in a sealed with a linkwitz-transform circuit or a dsp eq. Some very expensive Scanspeak and Acoustic Elegance drivers can also go below 20Hz.

But that pioneer driver you mention will not, in any box
 
indeed, that driver will never go that low loud. You need a special and big subwoofer for that as not many can do that. A cheaper example of one that can is the Dayton UM18-22 that can do that in a sealed with a linkwitz-transform circuit or a dsp eq. Some very expensive Scanspeak and Acoustic Elegance drivers can also go below 20Hz.

But that pioneer driver you mention will not, in any box

Hmm, pretty sure the links I mentioned should have covered that.

Anyway, the frequency response curve shape is determined by the box volume and tuning frequency, in conjunction with the driver's own parameters.

So, you use the box size & tuning controls on the "Box" tab to get the best combination of size/extension/flatness first.

Then, go to the signal tab and input the voltage that your amp will be able to generate in the "driver input voltage (each)" field (or just the speakers power rating in the "system input power" field, although this is a little less accurate in the real world than converting to voltage first).

Then go to the Cone Excursion graph to check that you aren't trying to push it farther than it can realistically move while still tracking the input signal in a reasonably linear manner.

Then go to the SPL graph to check it gets loud enough.

Then go to the Rear Port - Air Velocity graph and adjust the port dimensions (on the "Vents" tab) to keep velocity low enough - 17ms-1 or lower is ideal for hifi, though in some circumstances a bit higher may be ok. Note that once the box volume & tuning are set, adjusting the port dimensions won't result in any change to the main frequency response graph shape.

Changing the port size, length and cabinet volume should all affect the frequency response curve.
That said, the Pioneer TS-W312D4 has an Fs of 38Hz, Vas of 34.1 liters, and an Xmax of 7.7mm, it is not going to produce much output at 15-20 Hz, regardless of the box size or tuning (Fb).



Thank you now I got it.
please find screenshot of the values of the driver I have, what can you recommend for me to tune this sub to for in room use no problem if i cant go under 20Hz? I already have this pioneer sub so I want to make good use of it than buying a new one.
 
Factory or measured? Regardless, can't read it or expand without blurring even worse. :(

Factory: https://www.pioneer.com.au/wp-content/uploads/2021/02/TS-W312D4_S4-User-Guide.pdf

Thank you now I got it.
please find screenshot of the values of the driver I have, what can you recommend for me to tune this sub to for in room use no problem if i cant go under 20Hz? I already have this pioneer sub so I want to make good use of it than buying a new one.
https://ibb.co/5RJjcXV

Sorry for low res photo
https://jpegbay.com/gallery/008309983-.html#1

yes factory measures pdf is the one
https://www.pioneer.com.au/wp-content/uploads/2021/02/TS-W312D4_S4-User-Guide.pdf
 
OK, need to add at least a 1/2 ohm of series resistance for wiring, raising Qts to ~0.93 Qts':

[Qts']: [Qts] + any added series resistance [Rs]: Calculate new Qts with Series Resistor

[Rs] = 0.5 ohm minimum for wiring, so may be higher if a super small gauge is used as a series resistor plus any added resistance from an XO/whatever.

Note too that tuning > a 1/2 octave below Fs [~37*0.707 = ~26 Hz] usually dictates a compression loaded bass horn size box.

Going vented then will require some form of TL and to tune it all the way down to ~16 Hz to get any usable output when combined with room gain at ~20 Hz will need corner loading.