Winisd port length accuracy

[Crank_It_Up]

When using winisd pro to model an image dynamics IDQ 12 D2v3, box size just under 2 cubic feet, 4"x3" rectangular port (inside dimensions) it seemed like the port length of 20" was a little long. So I looked at image dynamics website, downloaded the specs, and then modeled it in a 1.5 cubic feet box with a 3" round port tuned to 30 hz. The port length was much longer with winisd than it was in image dynamics spec. Which one would you go by?

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[rumblebee2 10+ year member]

id

 

[IgnoreMe 5,000+ posts]

you are comparing a 2 cube box with 12" of port area to a 1.5 cube box with ~7 square inches of port. of course the port lengths are going to be different.

 

[mrogowski 5,000+ posts]

Port size/lengths that WinISD produces are quite accurate.

 

[bass_lover1 10+ year member]

Port size/lengths that WinISD produces are quite accurate.

It's kinda hard to **** up an equation that's been constant for probably the last 30+ years.

Unless of course you put in the wrong numbers, then blame something else.

 

[ngsm13 5,000+ posts]

you are comparing a 2 cube box with 12" of port area to a 1.5 cube box with ~7 square inches of port. of course the port lengths are going to be different.

This.

Port size/lengths that WinISD produces are quite accurate.

Oh and this.

nG

 

[madmaxz 10+ year member]

well say you go with the ID spec box size of 1.5ft^3 tuned to 30hz. should 1 use Ids recommendation of 3" round at 8.3" long or winisds rec. of 3" x 13" or a 4"x21"

 

[rumblebee2 10+ year member]

on winisd it says 3"x11.86" not 3"x8.3"

edit:3"x13"=28.85hz

 

[Crank_It_Up]

you are comparing a 2 cube box with 12" of port area to a 1.5 cube box with ~7 square inches of port. of course the port lengths are going to be different.

My post was only 4 sentences, but you managed to miss sentence number two. Here it is again, hope you can understand it this time...
"So I looked at image dynamics website, downloaded the specs, and then modeled it in a 1.5 cubic feet box with a 3" round port tuned to 30 hz."

I compared the identical box size, port size, length, and tuning from Image Dynamics website to Winisd but found the port length quite a bit longer in Winisd. I did that to test the accuracy of Winisd's port length, taking for granted that Image Dynamics was correct. Now I can't help but wonder which is right and which is wrong? Is the Image Dynamics box actually tuned higher than 30hz, or is Winisd's port length incorrect?

 

[madmaxz 10+ year member]

on winisd it says 3"x11.86" not 3"x8.3"

edit:3"x13"=28.85hz

again if people would just read.. 3" x 8.3 is image dynamics recommendation

 

[bubbagumper6 5,000+ posts]

Anyone else find it odd that you can put the EXACT same specs into both WinISD, and WinISD Pro and get 2 different answers?

 

[rumblebee2 10+ year member]

again if people would just read.. 3" x 8.3 is image dynamics recommendation

actually i did read. i was just pointing out that ID's measurements were off per winisd pro.

 

[Crank_It_Up]

I see that ID has from 0 to 2 lbs. of "poly fill" for that box, could it be that the poly fill makes up for the shorter port length?

 

[ngsm13 5,000+ posts]

Yes.

nG