I'm about to build a slot ported box for 2 Tidal Audio 12's (Image Dynamics ID V3's) that will by 45" wide, 15" high, and 17" deep. I wanted to give these subs about 4ft^3 after all displacements and tuned pretty low, maybe around 25hz.
I'm guessing I need about a 2.5" wide port, and the height would be 13.5. The length I'm not exactly sure on. I'm using the RE calculator (a bit off I hear), and Winisd Alpha Pro (also maybe a bit off). I'm getting numbers between 26-35 for length.
I'm wondering about port volume in relation to the size of the box. I think I've read you want to stay within a certain ratio, but I'm not sure what that it or exactly why that is. Maybe for port noise? Winisd says my subs at 600w with some eq'ing will not go over 100 ft/s.
Hope I'm not trying to over-think this, but I'd like to do it right the first time. Thanks guys!
as long as you are under 100ft/s you are good to go.
dont forget that the volume of the port needs to be subtracted from box volume.
dont forget to check where your excusion runs out. no use biulding a box that runs out of excursion before the tuning point.
dont forget to use a sub-sonic filter. ported boxes unload fast under the tuning point.
If I get the tuning right, Winisd says excursion shouldn't be passed till a bit under 20 hz...which I don't think any of my music, even bass songs, will hit. Don't have a subsonic filter, so I may get a 20hz FMOD. I was kinda worried about getting port length right for tuning since I'm getting two different answers from Winisd and RE's calculator. People say try Bassbox Pro, but I can't shell out $150 for that right now. I guess more length on the port would be the better "guess" seeing as how I want my low end solid.
Quote:
Originally Posted by Chaos
What he said.
Also, don't guess
I don't want to guess, I'd rather just know which program is lying to me But I wondered if I was just splitting hairs over a few inches of port length anyway.
And there's one question I forgot to ask for any Winisd users. When it asks for box volume, would you enter gross or net?
gross, winISd does NOT take port volume into consideration. you have to do that yourself.
As for the differences in length, most of the time it has to so with your end point interface. a flared end will require a different length than a straight end. how much difference are you seeing between the two programs?
Definately consider that Fmod or some other form of SSF. if you are hitting xmax at 20hz, I would set it for 25hz.
Original post whore!
Disclaimer:Opinions of the above are the property of the poster
Stock Sync HU |AC LC2i | Phoenix Gold EQ215i | Soundstream SA120 -> ID CD1eMH | JL 300/2 -> ID X65 | JL 500/1 -> (2) 15" Pyle PL1590BL in IB
Accounting for the driver's displacement and the port being made of 0.75" MDF with two internal sides (other two sides being made up by the top and bottom of the box) I get 22.96" length for the port and 23.55Hz tuning. Use the port as bracing, if you want to add more give me a volume of material to add and I'll factor that in too.
EDIT: With this design I get over excursion at 17-18Hz, so 20Hz SSF should be fine.
gross, winISd does NOT take port volume into consideration. you have to do that yourself.
As for the differences in length, most of the time it has to so with your end point interface. a flared end will require a different length than a straight end. how much difference are you seeing between the two programs?
Definately consider that Fmod or some other form of SSF. if you are hitting xmax at 20hz, I would set it for 25hz.
The differences are maybe 5 inches or so, but it looks like it only changes tuning a few hz if I go a bit shorter or longer.
Quote:
Originally Posted by The Baron Groog
Looks spot on.
Accounting for the driver's displacement and the port being made of 0.75" MDF with two internal sides (other two sides being made up by the top and bottom of the box) I get 22.96" length for the port and 23.55Hz tuning. Use the port as bracing, if you want to add more give me a volume of material to add and I'll factor that in too.
EDIT: With this design I get over excursion at 17-18Hz, so 20Hz SSF should be fine.
Are you sayng to use te port in the middle of te box? Ive seen people do that and put the subs on either side. Seems like it'd brace better than just using the port on one side.
Winisd also showed over excursion around there, I'll do the Fmod to be safe.
Yes, you can pretty much make the port any shape within the enclosure and use it to brace the top and bottom panels. Just remember to measure port length down the centre of the port, or down the two edges and averaged.
Fmod is a worthy addition whether sealed or ported, defo worth the $20-$30 I've seen them for.
Yes, you can pretty much make the port any shape within the enclosure and use it to brace the top and bottom panels. Just remember to measure port length down the centre of the port, or down the two edges and averaged.
Fmod is a worthy addition whether sealed or ported, defo worth the $20-$30 I've seen them for.
Ah yes I meant to ask about the correct way to measure the port but forgot. Thanks again Baron
Does this ported box look ok?
But I wondered if I was just splitting hairs over a few inches of port length anyway.
Linear Mode
