Ported enclosure size for the 18" beast!

**Mongrel714** · **07-12-07, 05:18 AM**

Another port idea

**Ilkka** · **07-12-07, 02:24 PM**

Quote:

Jerm357 wrote:

What do you think of his port opening being cut on an angle to get it flush with his design??

Hard to say anything definitive since I haven't ever tried such thing nor have ever even seen anyone done such port. But basically it isn't that bad, especially when we're talking about an 8" port which keeps the air speed pretty low. No need to change the plan.

**Mongrel714** · **07-12-07, 05:07 PM**

Thats all I need to hear. Im going to try it, I'll demo it before I paint it to see how it sounds, I'm just basically un-happy with any other design, so thaks for the input Ilkka, Steve, DS-21, and Jerm,`I really appreciate the help, Sat is D-day hopefully by monday I'll have a report!,
I did pick up a XLR connector and other cables today to hook up my amp correctly to my receiver so it ought to be alllllll goooodddd!
t is angled
Oh yeah, The part of the port that is angled, do I start my measurement from the lowest point or average the high and low points to start the measurements?

**Ilkka** · **07-12-07, 05:13 PM**

Quote:

Mongrel714 wrote:

Oh yeah, The part of the port that is angled, do I start my measurement from the lowest point or average the high and low points to start the measurements?

Average.

**Mongrel714** · **07-13-07, 02:36 PM**

After checking out my ceiling height in my living room I discovered I would not be able to tilt the sub up straight from horizontal, soo, I recalculated and dropped my height 6" and made the enclosure 2" bigger around (26"x 26") so now I have a little over 20 cu ft to play with, so it ought to sound pretty good!

**Mongrel714** · **07-13-07, 05:29 PM**

I'm not having any luck with WinIsd, cant seem to get an acceptable response, 566.4 liters, 8" port at ???length, I'm not able to adjust the port length in the program to change any measurements, Super steve, can you help me??

Thanks, Ill be cutting tomorrow and snapping pics as I go.

**SteveCallas** · **07-13-07, 11:32 PM**

I'd go for ~26.5" length, a ~14.5hz tune.

**Mongrel714** · **07-14-07, 04:51 AM**

Thank you Steve, I know you are spread thin around here so I really appreciate you helping us noobs, Heavy is the head that wears the crown! Hail to the King of SUBS!!

**vitod** · **07-14-07, 04:14 PM**

Your making Steve's head bigger than it already is.

**brucek** · **07-15-07, 08:06 AM**

Playing with WinISD that seems like a good match for that driver.

566.4 litres, 14.5Hz tune, 8" one end flared port @26.22".

6dB down @ 13.8Hz With 1st order electronics rolloff at 10Hz.

Maximum excursion of 39mm @ 9.5Hz with 900 watts at driver.

Under 8% port velocity @ 13Hz with 900 RMS watts at the driver.

transferfunc.jpg
excursion.jpg
velocity.jpg

brucek

**Mongrel714** · **07-15-07, 09:57 AM**

Thank you Brucek for the charts, I will figure win isd out sooner or later, are you using pro or the beta version?

**brucek** · **07-15-07, 10:05 AM**

Quote:

are you using pro or the beta version

I'm using WinISD Pro ALPHA 0.50a7

I created the RL-P18 D2 database from the specs on the SS site..... it requires using the WinISD database editor and then local modifying that to comply exactly with the SS site specs.

brucek

**Mongrel714** · **07-15-07, 10:19 AM**

I'm reconsidering hiding the awesome sub under the enclosure, Give me your thoughts on this design, problems etc. thanks guys.

**SteveCallas** · **07-15-07, 12:35 PM**

My model was based on the D4 - I'd probably suggest something else if using the D2. And I do suggest using the D2, it's just that SS came out with the D4 first and I never bothered to enter the specs for the D2.

As for the design, I'd keep the driver and port on opposite ends so that the port openings will have plenty of clearance in all directions from any obstructions.

**SteveCallas** · **07-15-07, 12:39 PM**

Yeah, the D2 moels differently then what I was looking at. I'd make that 8" port 30" long if you haven't cut it already.

**Mongrel714** · **07-15-07, 01:26 PM**

Cool, I'll keep it as is, and I actually left the port at work, so it is intact. I keep getting error messages when inputing data into pro, QES, QTS, etc. I'll keep trying till I get it right.

A couple more questions, how much clearance between the port and side walls?, and, can I use the four binding posts on the enclosure,( I ordered the single through the MDF posts) to change the driver from series to paralel wireing, or should I do it at the driver??

**Jerm357** · **07-15-07, 02:16 PM**

I used four post on my enclosure, just so I had all the wiring options open if I ever needed them.

Heres an unpainted pic of them....
Oh, and the clearance should be the width of the port opening. So for you it would be 8"

**brucek** · **07-15-07, 07:11 PM**

Quote:

I'll keep trying till I get it right.

mongrel,

Attached is my project file for sub I did the graphs for.

I appended a .txt extension to the file so it would attach to the site.

Simply remove the .txt extension and leave it a .wpr file (which is a project file for WinISD).

Put it in the WinISD project files at C:\Program Files\Linearteam\WinISD Pro\Projects\Mongrel RL-P18 D2.wpr

Run WinISD and open the project. Then you can modify the ports etc if you want....

brucek

**Mongrel714** · **07-15-07, 09:08 PM**

All right! thank you so much!
Hmm, cant seem to figure out how to drop the text ext. cant open the file.

**brucek** · **07-15-07, 10:06 PM**

Once you have saved the file to the directory I mentioned, right click the filename with the mouse and select rename and delete the .txt extension to leave the .wpr extension.

Now the file is a project file that can be read by WinISD.

brucek

**Mongrel714** · **07-15-07, 11:06 PM**

Quote:

brucek wrote:

Once you have saved the file to the directory I mentioned, right click the filename with the mouse and select rename and delete the .txt extension to leave the .wpr extension.

Now the file is a project file that can be read by WinISD.

brucek

Strange, when I try to re name it, the file name doesent show a txt extension, only wpr, even though it shows as a text in the project folder.

**Mongrel714** · **07-16-07, 04:51 AM**

Thanks brucek, that worked

**ISLAND1000** · **07-22-07, 10:51 AM**

My personal favorite arrangement that your drawings show is with speaker and vent on top, exposed. I think that's absolutely beautiful.
The practicality of having exposed speaker and vent open to the public however makes me shudder. What if a 2 year old with baby bottle decides to drop same bottle on the speaker cone or down the vent?
Would there actually be enough room on the speaker baffle to mount both the speaker AND the vent. I know the drawing shows it but my intuition says it won't fit as shown.

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