Cab BassLite S2010 impossible port length question

[NighthawkGS]

Hi guys... I am considering building (or converting existing cab to) a cab for one of my many Eminence BassLite S2010s, using one of the Eminence cab designs.

But the specified port length seems impossible to fit in the specified volume, if the port should only be half the length of the cabinet dimension in question.

Full cab design details below, highlights being:
Med Vented. 1x10"
V(total) = 1.063 cu.ft
2 round 8.6" vents.

If I can't get this to work, may buy or build a 1.2cf cab based on the Rumble 40 as discussed on TalkBass. not sure why that one uses short 2.5 in approximately ports, whereas eminence sayings to favor 8+in ports...

BassLite S2010 Med Vented. 1x10" Bass Guitar Cab
By Jerry McNutt, Eminence Speaker LLC
Displacement Limited to 140 Watts; F3 of 68 Hz.
Box Properties
--Description--
Name:
Type: Vented Box
Shape: Prism, square
--Box Parameters--
Vb = 0.9 cu.ft
V(total) = 1.063 cu.ft
Fb = 60 Hz
QL = 7
F3 = 67.93 Hz
Fill = minimal
--Vents--
No. of Vents = 2
Vent shape = round
Vent ends = one flush
Dv = 3 in
Lv = 8.663 in
Driver Properties
--Description--
Name:
Type: Standard one-way driver
--Configuration--
No. of Drivers = 1
--Driver Parameters--
Fs = 46.15 Hz
Qms = 4.16
Vas = 63.42 liters
Xmax = 4 mm
Sd = 350.1 sq.cm
Qes = 0.34
Re = 5.02 ohms
Le = 0.47 mH
Z = 8 ohms
Pe = 150 watts

 

[agedhorse]

Block off one of the vents and recalculate. Looks like WAY too much port area which is why you can't make the length work.

 

[jallenbass]

I built that very box for the S2010 and found it to be very boomy in certain ranges. I can't remember which ones right now. I tried altering the ports but gave up after one try. Same problem. It sounds great in my Rumble 40.

 

[NighthawkGS]

I built that very box for the S2010 and...

Thx...so, did you put the specified ports into a box that was less than twice as deep internally as those ports? I think I heard that was a No-No.

Yeah maybe I should try the rumble 40, or build a 1.2 CF (approximately) box based on it. I just made a box of about 1.53 c f total for a s2012, kind of hard to test it under current conditions, but somewhat promising and weighs 19 pounds!

 

[jallenbass]

Thx...so, did you put the specified ports into a box that was less than twice as deep internally as those ports?

I put them on opposite sides and the length specified.

 

[NighthawkGS]

Block off one of the vents and recalculate. Looks like WAY too much port area which is why you can't make the length work.

I didn't make it clear, I'm actually using the published Eminence cab designs, not using software myself. Can be Googled as Basslite_S2010_cab.pdf .

 

[NighthawkGS]

I put them on opposite sides and the length specified.

Opposite sides?

 

[jallenbass]

Opposite sides?

Left side, right side.

 

[basscooker]

Why not side ported? Maybe not optimal but it won't change the resulting performance provided sufficient breathing room. I would question top or bottom ports though

 

[Downunderwonder]

I don't know where you got the half length idea.

So long as you have a full diameter of clearance you are mostly in free air. They are 3'' diameter ports, 8.6'' long.

Other option is the shelf ported coffeehouse cab which many have duplicated, with that driver. I think it's tuned a bit lower from memory.

 

[NighthawkGS]

So long as you have a full diameter of clearance you are mostly in free air. They are 3'' diameter ports, 8.6'' long.

Oh! Maybe I misunderstood, guess I need clearance equal to the width of the port, not the length. D'oh! I went to considerable trouble to make this cab deeper... And also to decrease the width, both of which are visible in photo.

 

[agedhorse]

I didn't make it clear, I'm actually using the published Eminence cab designs, not using software myself. Can be Googled as Basslite_S2010_cab.pdf .

I don't think Eminence would publish a design that couldn't be built, Jerry's a pretty savvy guy.

Oh! Maybe I misunderstood, guess I need clearance equal to the width of the port, not the length. D'oh! I went to considerable trouble to make this cab deeper... And also to decrease the width, both of which are visible in photo.

A few inches from the opposite surface is plenty fine.

 

[yodedude2]

I don't know where you got the half length idea.

So long as you have a full diameter of clearance you are mostly in free air. They are 3'' diameter ports, 8.6'' long.

Other option is the shelf ported coffeehouse cab which many have duplicated, with that driver. I think it's tuned a bit lower from memory.

here's the 'coffeehouse cab' thread: Low-cost DIY practice/coffeehouse tweeterless 110 [long] i built a couple of these from plywood using s2010s and am rather pleased with them.