Tuning Frequency Mistakes

This is also a matter which if was a lesson on your school,it would be definitely in the Grade 12th of the NonKnowledge.

This is a very common mistake mostly done from those who are making subwoofers and more deep in detail,car subwoofers.

You're pretty basically getting a random woofer driver that is rated at 100000w and making calculations for a ported box that can tune as lower is possible at crazy frequencies like 10hz? 20hz?

If you are one of those,this article seems that is written and dedicated to you.


So i wont go far with this post because it has a pretty simple explanation,but... There's a lot of details.

As you probably already know i'm considering this as a huge mistake and that is correct.
Why this is happening? Because it's wrong and leads you with a useless subwoofer while you're thinking it blows out 10 Grand of (useless) Watts and it can tune on 5hz.

The speaker drivers are having a Frequency Response,and there useable frequency response can't be extended using a cabinet that tunes lower.

For example let's say i have a JBL Professional Woofer Driver which is made for vented cabinets and it's useable from 60hz to 4khz while it might be heard on 50hz but much quitter (at -6db or maybe more) and it has FS 48hz (the frequency in which resonates).
If i want to use it properly i should read the manual or datasheet to see its specs and maybe the suggested cabinet size in volume so i can make a corresponding box with tubes that can tune from about 50hz to 60hz.

Tuning the box to 50-60hz = Great sound,and tunes to 50-60hz which can be produced by that driver.

Tuning the box as low as 20hz without having a clue about what you're doing = Lose sound,bad accuracy,the driver exceeds its Xmax easily and resonates similar to Free Air.
Everything will sound bad,and if a miracle happen it might produce those 60hz we were talking about,but nothing bellow than its driver's capabilities,and also it will have very bad midrange frequency response.

Also another extremely HUGE mistake is when someone's putting a driver made for example 150hz sealed boxes into a vented one that tunes lower.

Clearly,it will not only tune lower,but it wouldn't sound like a normal speaker at all... Imagine how your woofer will sound working in free air on the corner of your room and take that for example.

You should also remember that you can't build up a speaker that wants to be called "High Fidelity" only by buying a random driver that looks good and make some calculations to build up a box,but you can try to take driver's best result by taking the advice of the manufacturer and put the driver into a proper box.