Cone control

[Nikuk 1]

I've grown concerned about something that I see all over the audio forums: People stating that tuning a ported enclosure has nothing to do with the woofer.

Couple of quetions / points to discuss:

How many here believe this?

For those that do, why? By that, I mean, because someone else told you so or because you've done some reading somewhere? If so, where...

Wouldn't it make sense that the woofer acts upon the port by nature?

Considering displacement, excusrion, fs, & emf properties... I'm under the impression that a woofer will interact with the port design, not act independantly.

For reasonable / average installations this isn't a big concern I suppose... as the mechanics shouldn't suffer too much. But is you are trying to design a rather efficient enclosure for clean or loud response... this does matter.

[Discuss]

[Tirefryr 1,742]

The actual tuning frequency of the vent is tuned without the driver. Theoretically. Once you add the driver, then place the cabinet in the vehicle, you can pretty much throw everything out the window. Each specific thing is interacting with the entire environment. Hence the question of APPLICATION, rather than a simple ENCLOSURE.

My biggest problem I've had is dealing with the individual transfer function variations and reflections between vehicles.

[Nikuk 1]

Exactly what gets me peeved.

Tuning frequency is NOT completely independant. Every part of the woofer (from motor to soft parts) has it's own properties.

But, thank you for pointing out the tuning frequnecy portion. Most people I see say "tune your box to this with this"... never accounting how much port area the driver needs. Much less so any concern over linearity.

Transfer function & low end extension in-car is a whole nother topic. Again, IMO, unless you are serious about SQ or SPL... you have little need to run sealed FR testes in car.

-but-

It would not hurt any install... helping understand the acoustics of the interior.

Reflection & cancellation can make it more challenging.. but that can be accounted for as well.

My real problem here is 'kid's' stuffing a 3" x 9" PVC pipe into a 2ft^3 box for a Acme 12" and running 1kw to it. Then saying, it sounds alright... but not as much as I hoped for. Even though... the BOX is tuned to 30hz.

[Tirefryr 1,742]

My real problem here is 'kid's' stuffing a 3" x 9" PVC pipe into a 2ft^3 box for a Acme 12" and running 1kw to it. Then saying, it sounds alright... but not as much as I hoped for. Even though... the BOX is tuned to 30hz.

I've been there. Then ordered the Loudspeaker Design Cookbook from Crutchfield. Then I got lost. Then I aged. It'll come in time. If not, I just let them hold firm in their own beliefs, or should I say ignorance.

[dave_Edwards 1]

I have always looked at it this way----you can tune an enclosure to the speaker or the vehicle never both----the FS of a vehicle is never the same as the tuning of most enclosures(SPL vehicles being a differant story)----

IE---you have a 15 tuned to 32Hz in a 3.3 enclosure then put it in a vehicle with a 54Hz FS----it might sound good----but you will have to play around with it and try differant enclosures to see which enclosure sounds best----some vehicles tend to have better "low end ummp" (meaning it can raise the lower end response of a given enclosure---example CRX's) my MAgnum is my test bed now and I can tell you this---I am having problems with 75-110Hz and I am trying to figure out a way to get better imaging upfront-----this is the funnest part of car audio for me---try newer and better things----it might be differant but it will sound better in the end.

[mrray13 30]

well, like u corrected me earlier...i try to use three basic things: xmax(for port area) and displacement(for box volume) and fs(to help determine what i'm tuning at) why?

1) for everyday installs, they are the only three things that matter to make just about anything sound good to just about anybody

2) because i honestly don't know enough about physics and electrical engineering to speculate about transient response, qts, qms ,pms and whatever else u wanna throw at me...lol...

though i know the things in number 2 to indeed relate to how a subwoofer will ultimately sound in vehicle, for what most ppl are after, just knowing those three things i listed is usually way more then enough.

but then again, i'm learning all the time, so all this may change...

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

[Nikuk 1]

bah, i dont know what I should.

[Tirefryr 1,742]

The general rule of thumb is:

An enclosure built to Vas, tuned at Fs will have an F3 of Fs.

Of course, add in the vehicle or room and that all changes. Also, the parameters will change throughout the use of the driver as well. It's basically just a big guessing game we're playing. We are all fools!