Box/Sub tuning

[2023 LTZ]

I’m trying to understand box and or sub tuning. Is this a consideration in box construction by an individual? Do prefabricated boxes have a theoretical range? Can it only be changed by making adjustments to the port of an existing box? Would the same box have a different tuned hz level w different yet same size subs bc their physical mass is different? If I determine my ideal hz level, is this the loudest it is mechanically and physically capable of?
If a song has lower than this level are there audible warning signs? Is it distortion?
I googled this topic and it doesn’t have much in the way of an explanation. Plenty of info on doing it but not why.. I also did a search on this site and the word box does come up a lot but not in a way that explains this topic.

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[SHO'NUFF]

I’m trying to understand box and or sub tuning. Is this a consideration in box construction by an individual?

Yes

Do prefabricated boxes have a theoretical range?

Yes

Can it only be changed by making adjustments to the port of an existing box?

No, you can add blocks of wood or something to take up space inside the box as well. You can also face the subwoofer backwards, meaning basket and motor on the outside to increase the volume inside the box. As long as the subwoofer has a vented pole piece there will be no difference in performance.

Would the same box have a different tuned hz level w different yet same size subs bc their physical mass is different?

Yes, for more reasons than just the mass difference between the speakers.

If I determine my ideal hz level, is this the loudest it is mechanically and physically capable of?

No, you can build a box that will get loudest your speaker is capable of, but you won't like the way it sounds. SPL boxes typically have a huge spike in response at the natural resonant frequency of your car. You probably want to tune low 30's for music.

If a song has lower than this level are there audible warning signs?

Yes, decreased output, the speaker moves a lot more because there's less pressure helping control the speaker. There's more pressure in a ported box than a sealed box at the tuning frequency. There will be popping sounds of the voicecoil hitting the backplate if it goes too low with too much power.

Is it distortion?

No

I googled this topic and it doesn’t have much in the way of an explanation. Plenty of info on doing it but not why.. I also did a search on this site and the word box does come up a lot but not in a way that explains this topic.

PartsExpress has books on building boxes. My favorite is the loudspeaker design cookbook.

 

[1aespinoza 10+ year member]

I’m trying to understand box and or sub tuning. Is this a consideration in box construction by an individual? Do prefabricated boxes have a theoretical range? Can it only be changed by making adjustments to the port of an existing box? Would the same box have a different tuned hz level w different yet same size subs bc their physical mass is different? If I determine my ideal hz level, is this the loudest it is mechanically and physically capable of?
If a song has lower than this level are there audible warning signs? Is it distortion?
I googled this topic and it doesn’t have much in the way of an explanation. Plenty of info on doing it but not why.. I also did a search on this site and the word box does come up a lot but not in a way that explains this topic.

From all I have read, watched, and discussed, a 40Hz box is going to be just that; a box with a resonant frequency of 40Hz. At that frequency is when that box will be loudest. For it to resonate at that frequency, it must have sub/s capable of making it resonate. For that reason a box is designed for the parameters of a sub. It is easier to build a box than a subwoofer (Although Sundown says they designed their subs to meet the box specs).
Changes to box size, port length, or port area will change the Fs of a box. This is because the air inside a port is a "weight" that must be moved. So when you modify the port, you change the "weight" of the air inside it, thus changing the Fs of the box.
Now there is the question of the type of car it will go into. The vehicle is basically another box in which the sub box will go into. I think that is like a 6th order box, not sure. That is the gist of it, although there is alot more to designing boxes. It is an art in itself and I am on the outside looking in.

 

[2023 LTZ]

Gents
I appreciate your knowledge and you sharing it. This is helpful in my understanding.