The tuning of woofers/cabinets

[vernb]

I am really not sure I understand the tuning thing. I thought that if I take a certain woofers t/s data and calculate on them, then I would get one result only, with the best size cabinet for that particular woofer????

But I see things like this all over this forum:

"tuned to 30hz", or "the box is appropriate size for HiFi tuning, not extended bass" ????

I don't get this. So in a JBL S3100: Is the ME150H tuned for hifi or extended bass or both at the same time? It certainly seems to play both.

Can someone please enlighten me here, thanks

I want extended bass to 30hz flat, but also to play up to 900hz to a 1" driver. Does that mean that I have to have two 15" woofers in separate cabinets, like 4435?

Vern

[Robh3606]

Hello Vern

There are several ways you can tune a box to get the desired result. If you run a box program like WinISD you get what is called maximally flat response curve and tuning. You can then adjust the box tuning to get your desired response. Download WinIsd and try this. Run the program with a 2235 and an LE-14H. Change the volume too 5.5 cubic ft and 30Hz for the 2235 and then 3.5-4 cubic ft and 30Hz on the Le-14H. These are closer to what JBL used in the 4434 and L250 and you can see why immediately. That's the best way to understand what is actually happening. The box tuning primarily effects the lower range of the drivers response curve. The top end is more or less independant from how you tune the box. Finding a 15" woofer that has good response below 40Hz and up to 1-2K is not an easy thing to do.

Rob:)

http://www.linearteam.dk/default.aspx?download=winisd

[vernb]

thanks Rob. Is that a homebuild XPL200 in yours avatar?

[Zilch]

Bass Box 6 Pro offers four "design priorities" for suggested vented box designs:

High Output
High Fidelity
Extended Bass
Desired F3

For any driver, these represent points on a dynamic continuum trading box size and tuning frequency against the fixed driver parameters. You can also enter box parameters manually to adjust the design toward specific objectives.

In WinISD, what's going on is revealed by clicking and sliding the mouse on the box illustration, which changes the box size and frequency concurrently, and watching how the curve shape is altered in response. :thmbsup:

[Robh3606]

Is that a homebuild XPL200 in yours avatar?

Yes it is. You have a good eye! Here's a better size photo. Instead of just changing the box size and tuning you may want to just run a second 2235 and LE-14. WinISD lets you plot multiple drivers at once so you can easilly compare the curves.

Rob:)

[Ian Mackenzie]

Yeah , seen it too..show off...LOL

How about a look at some of your latest finger painting (aqua....las)?