Phoenix Gold Phorum

I've been playing around a bit with WinISD trying to learn how to optimize vented enclosures, and to be honest I've had mixed results.

I have a basic understanding of most of the different plots and graphs, but what I need is a little guidance in interpreting them all in order to design some great sounding vented enclosures. What do you guys look for when analyzing the graphs? What do you stay away from?

Some of my poor results when using the software have included tuning frequencies that were way too low, or excessive port noise. That's a perfect example of what I'm talking about. I know there is the Port Air Velocity function but I'm not sure how to properly test and/or read the plots. Do I apply real world power or just analyze the small signal results?

My current project is a single RSDc122 that I plan to power off the rear channels of a Xenon 200.4. I'd probably run it sealed if I had some more power to shove down it's throat. But given the power I'd like to design a kick ass slot vented box that will really pounds while maintaining decent low frequency extension. For those of you that are really comfortable with the software, how would you design this box?

I know I'm just not using this tool to its potential, so please show me the light!

I don't know...maybe this is a good topic for a proper How To thread?

which version are you using? Alpha or beta?


Portnoise <25m/s for no noise
Try using square ports (so a rectangular, actually) and converting that to an L port round the box
Don't forget you need to oversize the final box to fit the woofer displacement

add in real-world power for XMax simulation; add in a Linkwitz with something like 0.707. 57Hz, 0.707, 15Hz for in-car gain in a small car, lower it slightly (to say, 53Hz) for a Mid-size, depending on the size of the car (longest length x 2, get the wave length from one of the calcs on the web) and it should give you an idea of what to expect.

throw up a copy of the specs you're using and the box you were thinking of....

Bret

there is a thread on speakerplans.com that discusses winisd pro and hornresponse. i havent checked out the part on winisd but the stuff on hornresponse is how i learned to use that program. it is more geared towards pa use but you might give it a quick read to see if it helps you. http://www.speakerplans.com/forum/guide ... c1314.html

I've got the Alpha version on the PC at work. I just found the T/S parameters you posted for the RSDc's Brett. It'll be nice to have that degree of accuracy. What boxes have you designed for the RSDc12?

I had just started to play around before the end of the day but I was at 2.5 cubic feet tuned to 28hz. I had a 2.5" x 12" vent if i remember right and it was thirty something inches long. IIRC the vent was really noisy. Am I just tuning way too low?

I can't remember and TBH, I haven't got WinISD installed on this win7 box yet

Will have to do some modeling later.

Bret

dedlyjedly wrote: I had just started to play around before the end of the day but I was at 2.5 cubic feet tuned to 28hz. I had a 2.5" x 12" vent if i remember right and it was thirty something inches long. IIRC the vent was really noisy. Am I just tuning way too low?

Port air velocity goes down as the port cross sectional area goes up. Increase the size of your port, and it should cut down on noise. But, when you increase the CA, then the length has to get longer to maintain the same frequency, there comes a point where you don't have enough room for the port. It does not hurt to have part or all of the port out of the box if it comes down to it.

Later,
Jason

So the one thing I've always wondered, is the ports displacement included in the box's overall volume? Or do you have to take the cf of the box plus the port.

Example: Box= 2 CF w/a port of 6" x 4" x 15" long. Does that 6x4x15 inch port go inside of that 2 CF? Or on top of?

I've always done it in addition to the CF of the box.

... which is correct. the box volume is THE BOX only, no sub, no port included.

Bret