6th order help!

[dsw422]

Hey guys. 

Trying to design a series tuned 6th order for a single Sundown X-15 powered by 3000 watts. I've talked with a few builders on facebook and most have said for lower fs subs which the X is, they tune the rear chamber near 24hz. 

With that said, I'm using WinISD to design 2 separate ported boxes which will represent a series 6th. I've been told to download hornresp, but my computer won't do it.. so I'm needing some help..

When on WinISD, designing the rear chamber to 24 hz at 2.5 cu.ft., the port has to be huge and extremely long to to accomplish this.. for example: port is 8in diameter but requires 88in length. That is just extremely too long!

Am I doing this right? Any help is greatly appreciated.

Ps. Box size limit is 49"w, 40"d, 27"h

[ShadeTreeMechanic]

That is the dilemma with small boxes. You often see huge flared external ports when this happens. The reason you should use horn resp is that when you add the front chamber, it changes the port for the rear chamber. I believe the front chamber port adds to the rear chamber port to cause the rear chamber port to be shorter. I don't have horn resp but I read a thread here all about it. You should do a search here. Tons of good info if you are willing to look. The front chamber will need to be huge and is why most people can't run them.

[Wasteland_Audio]

Triticum made a thread about series tuned 6th orders a while back that explains how all this works. Basically what happens is you end up chasing your tail trying to keep the rear chamber tuned as you adjust the front chamber. I'll try to find the link to that thread tho.

[Wasteland_Audio]

 

[rocking.that.eclipse]

How many square inches of port are you aiming for in your rear chamber? Usually we try for like 6 to 8 per cube thats how you compensate for lack of room

 

[dsw422]

Thanks guys for the responses.. I finally got to download hornresp.. although it's gonna take some reading and testing to figure it out.. 

 

As far as what port area I was using for the rear chamber, it was an 8 inch aero port for a 2.5 cuft rear chamber. I'd think that 8 sq.in. of port area per cube is very small.. but I don't kno 6ths very well either..

[Wasteland_Audio]

You can run a lot smaller port in the rear chamber because you'd never hear the port noise after it passed through the front chamber.

[dsw422]

8 minutes ago, Wasteland_Audio said:

You can run a lot smaller port in the rear chamber because you'd never hear the port noise after it passed through the front chamber.

Never thought about it like that.. but how much smaller could it be? 

I also read Triticums thread u shared.. unfortunately without knowing how to use hornresp right now (it'll take some time) I won't be able to model it correctly.. 

With that said, I might take the help Ive recieved from builders and designers on facebook for now and tune rear port to 24 hz (for this sub) and have an adjustable port for front chamber.

[Triticum Agricolam]

To expand on what others have said, you really can't use WinISD to model a series tuned box.  They are too different from parallel-tuned boxes and the results WinISD gives you will be useless.

 

HornResp has a bit of a steep learning curve, but I'm more than happy to help you out with it.  Just let me know.

Its true that if you undersize the rear chamber port you probably won't hear the port noise, but there will still be a big loss in output from the port compression.  

[dsw422]

17 minutes ago, Triticum Agricolam said:

To expand on what others have said, you really can't use WinISD to model a series tuned box.  They are too different from parallel-tuned boxes and the results WinISD gives you will be useless.

 

HornResp has a bit of a steep learning curve, but I'm more than happy to help you out with it.  Just let me know.

Its true that if you undersize the rear chamber port you probably won't hear the port noise, but there will still be a big loss in output from the port compression.  

Thanks Triticum. I'd love some help with hornresp. I'm gonna watch a bunch of tutorials, read a bunch and try it myself. When a question  (and I'm sure there will be plenty) comes up, I'll ask.

 

But for now, would u be able to help me design a 6th for a friend I'm gonna build for. 

Box is for a Sundown X-15 on 3000 watts.  Max dimensions are 49"w, 40"d, 27"t. All I'd need is chamber volumes and port lengths and area.