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15" 16 ohm Speaker Options?

#43
johnfitz44 said:
Perhaps I'm crossing up terms here. I may be using the term "ported" when I should be using the term "vented". I have an 8 1/2 inch by 3 1/2 inch (vent?) cut into the front panel of the speaker cabinet. Make sense? Therefore, depth of the vent is the 11" which I measured between the plywood front to the back of the box.
Click to expand...
Ported/vented=tomato/tomatoe.

Currently, your port is 8.5x3.5 with a depth equal to the thickness of the baffle, not the 11-13" required.
 
#44
well i ran it again and i used 2.9cf for the sim just as a guess for remaining usable space after the new port and driver was installed. again just a guess. your existing port would have to be lengthened to about 20 inches for a tuning of 37.22hz. i didn't think this was viable and would take up too much airspace in the cab. i would suggest sealing up the existing port and installing a 5" round port at a lenth of 13.15". also there are several port calculators online just google them.
 
#45
Just with the slightest skimming, I'd again remind that when a vent uses a side or bottom wall as one of its boundaries that I've found you will only need 66 to 70 percent the length to achieve the desired tuning. This has borne out for me so far when testing with sines.

What's this mean? If WinISD is saying a port so wide and so tall needs to be 10" deep to get a certain tuning, it only needs to be 6.75" or so deep to achieve that tuning if a sidewall or bottom is part of the vent.

Remember to always subtract the total area of the vent and shelf. It makes for a moving target in cab's internal volume just to keep things interesting ; }
 
#46
greenboy said:
What's this mean? If WinISD is saying a port so wide and so tall needs to be 10" deep to get a certain tuning, it only needs to be 6.75" or so deep to achieve that tuning if a sidewall or bottom is part of the vent.

Remember to always subtract the total area of the vent and shelf. It makes for a moving target in cab's internal volume just to keep things interesting ; }
Click to expand...

Here's a thought - doesn't that mean that the extra vent length due to the sidewall or bottom effect must be subtracted from the cab volume? Though it's probably a moot point as various losses within the cab will cause the woofer to perceive a greater than actual volume!

Alex
 
#47
alexclaber said:
Here's a thought - doesn't that mean that the extra vent length due to the sidewall or bottom effect must be subtracted from the cab volume? Though it's probably a moot point as various losses within the cab will cause the woofer to perceive a greater than actual volume!
Click to expand...

I've thought about that too, Alex. I arrived at the 66% figure by audio tests but perhaps if the additonal volume would need to be subtracted in WinISD that figure itself would end up being different - no longer 66%.
 
#48
CrackBass said:
well i ran it again and i used 2.9cf for the sim just as a guess for remaining usable space after the new port and driver was installed. again just a guess. your existing port would have to be lengthened to about 20 inches for a tuning of 37.22hz. i didn't think this was viable and would take up too much airspace in the cab. i would suggest sealing up the existing port and installing a 5" round port at a lenth of 13.15". also there are several port calculators online just google them.
Click to expand...

Again everyone. Thanks for all the comments.

I'll do a little research into sealing up the existing port.

And I'll track down these port calculators online. My question would be:

1) Say I do go with the idea of putting a 5" round port? Top left above the 15" driver is the only place it could go. Unless I port it out the back like my Eden 410T. 5" diameter?

2) And again excuse my ignorance, but "at a length of 13.15"? A slight miscue with my calculation earlier, but I only have 12" to the back of the box?

Is this impossible with the box I have?
 
#49
the port length of 13.15" means a pipe/tube 13.15" long, with an inside diameter of 5". one end should be flush with the front of the baffle. (actually it doesn't have to be but that makes for the neatest looking job.) as far as port placement after i patched the existing port wouldn't there be room to put the port in the same place. a pic would help as i'm flying blind here.

cut some ply about 1" larger all around than the hole. screw this to the inside of the baffle. if you screw from the front sink the screws just a bit so you can patch them later. then cut a piece of ply the same size as the hole or slightly smaller. you might want to trace this before you install the prievious piece. caulk the inside joints then glue in the other piece. bondo and sand all the seams and holes, them spraypaint the entire baffle with some flat black. then cut a new hole for the port. a hole saw would be ideal if you can find one large enough. otherwise a spiral saw of jigsaw will be your only option. go slow and cut a hole that's smaller than you need at first, then slowly work it to the desired size. if you mess up a little then just patch the hole after you glue in the port. if you mess up bigtime then repeat all the steps till you get it right.
 
#51
CrackBass said:
the port length of 13.15" means a pipe/tube 13.15" long, with an inside diameter of 5".
Click to expand...

Yeah. But, the inside of the box is only 12" deep. I don't have 13.15". It's a tall shallow box. Inside dimensions = 12" deep, 23" height, 25.5" wide. With a sealed 12" x 12" x 11" box in the top right for a 10" speaker. This 8.5" long 3.5" vent is in the lower right corner. Perhaps it's not even supposed to be a vent. They made a version of this cabinet with a horn (SVT 1510HE). Maybe that's just the prefab for the horn. On the non-horn versions it sits empty? :confused:

Picture:
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#54
johnfitz44 said:
Yeah. It is getting quite epic in scale. Round port won't work with dimensions given. See above post WITH PICTURE. Tell me what you think?
Click to expand...

That is a rectangular port - nothing to do with a horn cutout. Well, assuming the company had someone who had a clue... which until I read the box size again, can't really say whether that might be a useful tuning, or needs some additional length beyond the baffle thickness.
 
#56
greenboy said:
That is a rectangular port - nothing to do with a horn cutout. Well, assuming the company had someone who had a clue... which until I read the box size again, can't really say whether that might be a useful tuning, or needs some additional length beyond the baffle thickness.
Click to expand...

Box size for the 15" speaker 3.25 cubic feet. Taking into consideration the displacement with the driver in the box = ??? 2.9 cubic feet ???
 
#57
Assuming you haven't fudged the internal space, and the baffle is .75" thick, a 3.5 x 8.5 hole tunes it to around 68 Hz. Too high for any decent bass guitar woofer alignment.

62 Hz tuning would require that it be around 1.89" deep (not such a great one for any driver I'd hang around with)

55 Hz tuning would require that it be around 3.62" deep (a little better typically)

48 Hz tuning would require that it be around 6.16" deep (now we're closing in on familiar territory for some nice drivers in that box size)

41 Hz tuning would require that it be around 10.11" deep (probably too low for most bassist's tastes with some familiar drivers)
 
#59
Ok, for 2.9 cf:

72 Hz tuning would require that it be around .75" deep

62 Hz tuning would require that it be around 2.66" deep

55 Hz tuning would require that it be around 4.6" deep

48 Hz tuning would require that it be around 7.44" deep

41 Hz tuning would require that it be around 11.87" deep

I don't even want to get into the port-chuffing issues at higher levels, which I would have to enter that driver in my database to check out. But generally I'm used to deeper shelves with more cross section to prevent that when using a lot of watts and playing lower.
 
#60
greenboy said:
Assuming you haven't fudged the internal space, and the baffle is .75" thick, a 3.5 x 8.5 hole tunes it to around 68 Hz. Too high for any decent bass guitar woofer alignment.

62 Hz tuning would require that it be around 1.89" deep (not such a great one for any driver I'd hang around with)

55 Hz tuning would require that it be around 3.62" deep (a little better typically)

48 Hz tuning would require that it be around 6.16" deep (now we're closing in on familiar territory for some nice drivers in that box size)

41 Hz tuning would require that it be around 10.11" deep (probably too low for most bassist's tastes with some familiar drivers)
Click to expand...

So, say I want to shooot for 48Hz. I build an elbow 6.16" deep like this:
[Invalid or Expired Link Removed]

Following say these rules for slot/ducts:
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