Is this driver a good value candidate for simple 100W 3 to 4 cubic foot sealed sub? - diyAudio
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Old 8th September 2011, 06:01 PM   #1
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Default Is this driver a good value candidate for simple 100W 3 to 4 cubic foot sealed sub?

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Vifa NE315W-04 12" Neodymium Woofer


link to partsexpress product page....
Vifa NE315W-04 12" Neodymium Woofer

low volume, low demand, highly accurate low bass for 100 percent music (no HT).
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Old 8th September 2011, 08:58 PM   #2
johnr66 is offline johnr66  United States
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I ran it through WinISD. With Qtc of .71, it needs a 1.83 Cu ft. box. F3 at around 45 Hz. It is not very efficient 4 ohm driver at 88.6db 2.83v/1m (85.6db/1w). 10db down at around 25Hz. Seems to be good for what you want. Larger box won't help the F3 point but slows the roll off a bit. Not much of a point to put it in a larger box.

With a 3 to 4 Cu Ft. box, your options are wide open with a 12". You really only need 1.2-2 cu ft. sealed for most decent 12"s.
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Old 8th September 2011, 09:37 PM   #3
sreten is offline sreten  United Kingdom
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Hi, That driver should be vented in a 3 cuft box, 20Hz, 3" dia 14" length port, rgds, sreten.
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Old 12th September 2011, 05:51 PM   #4
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Thank you for the input.

Specifications: Power handling: 150 watts RMS/300 watts max VCdia: 2" Le: 0.38 mH Impedance: 4 ohms Re: 2.8 ohms Frequency range: 25-1,000 Hz Fs: 20 Hz SPL: 88.6 2.83V/1m Vas: 7.12 cu. ft. Qms: 15.6 Qes: 0.32 Qts: 0.31 Xmax: 9 mm Dimensions: Overall diameter: 12.40", Cutout diameter: 11.20", Depth: 6.55".

Is this sub driver marketed toward car audio? Good candidate for home audio? FS looks good but I'm not that good at interpreting the finer TS points as they'd apply to a home subwoofer.

I actually ordered it so it's too late now. Hope I don't regret it. But I intend it as a single sub with 150watt plate amp for 100 percent music use in the home. Looks like quite a lot of quality and respectable name for 115 bucks. Although I hate it when they toss out stuff like...

Quote:
...with a butyl rubber surround designed by finite element analysis for linearity of performance.
I suspect FEA is even used in toilet paper manufacture in 2011. Wouldn't expect that kind of hype from Vifa. Unless they are aiming for the car stereo market with this.

I'll shoot generally for the dimensions listed by Sreten. I recently picked up a pair of A/D/S L520 speakers at goodwill. 7 inch driver, 1 inch dome. Out of the box condition. The Vifa neo sub looked like a nice candidate for a box to nestle between them. Many years ago I owned a trio of 3DAcoustics sub/sat from around this era. Sealed 5in with 1in dome sats. 10 inch DVC ported sub passively driven. Thought I'd aim for a similar sound.
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Old 12th September 2011, 07:11 PM   #5
johnr66 is offline johnr66  United States
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So are you going ported or sealed? If sealed, A 2 Cu Ft. box will do.
If ported, 3.3cu ft. 4" dia port, 13" long for 25Hz tuning.
This driver leans towards ported, but not so much that you couldn't go sealed.

I don't recommend a 3" dia port or tuning below 25Hz. Tuning it below 25Hz means you lose efficiency in higher bass where most of it resides and the F3 point actually rises.
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Old 12th September 2011, 08:04 PM   #6
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Hmm, dialing in on something good.

I'd have preferred sealed, I think, but I simply want what's best for the new family addition here. I have a prejudice, for no real valid reason except a hunch, that bass reflex is always just a little soft and "boomy" no matter how well tuned. Hopefully this project will disabuse me of such.

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Prelim sketch. Modeled after the old 3dacoustics one i mentioned, which I always thought had nice lines. Front grille is just cosmetic. Rear firing driver. Amp will bolt in above the driver. There will be at least one internal brace with circular cutouts. Very small amount of fiberfill inside (or not.... we'll see).

Suggestions regarding this layout?

Last edited by peace brainerd; 12th September 2011 at 08:13 PM.
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Old 12th September 2011, 08:28 PM   #7
sreten is offline sreten  United Kingdom
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Quote:
Originally Posted by johnr66 View Post
So are you going ported or sealed? If sealed, A 2 Cu Ft. box will do.
If ported, 3.3cu ft. 4" dia port, 13" long for 25Hz tuning.
This driver leans towards ported, but not so much that you couldn't go sealed.

I don't recommend a 3" dia port or tuning below 25Hz. Tuning it below 25Hz means you lose efficiency in higher bass where most of it resides and the F3 point actually rises.
Hi,

The F3 point is supposed to rise, low tuning optimises F6 not F3.

It also has superior transient response to the higher tuning, should
interact with room gain better, and will more likely avoid sounding
boomy, more like sealed than maximally flat F3 optimised designs.

rgds, sreten.
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Old 12th September 2011, 09:31 PM   #8
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by sreten View Post
Hi,

The F3 point is supposed to rise, low tuning optimises F6 not F3.

It also has superior transient response to the higher tuning, should
interact with room gain better, and will more likely avoid sounding
boomy, more like sealed than maximally flat F3 optimised designs.

rgds, sreten.
Agree. But there is one drawback:The port air velocity when exceeding 4 W input power is more than 10 m/s. See the MJK simulations.
FYI:Added a few more HR simulations too.

b
Attached Images
File Type: gif 1-Vifa-NE315W-04_ported-box_HR.GIF (183.8 KB, 159 views)
File Type: gif 2-Vifa-NE315W-04_ported-box.GIF (116.2 KB, 157 views)
File Type: jpg 3-Vifa-NE265W-04_NE315W-04_OD-ML-TL_HR.jpg (192.6 KB, 156 views)
File Type: gif 4-Vifa-NE265W-04_NE315W-04_closed-box.GIF (190.7 KB, 21 views)
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Old 12th September 2011, 10:14 PM   #9
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Quote:
Agree. But there is one drawback:The port air velocity when exceeding 4 W input power is more than 10 m/s. See the MJK simulations.
Does >10 m/s suggest noise? What is the alternative? Wide slotted port? I'm probably misapprehending this.

I never listen to music very loud. But I definitely like to have a sub going most of the time. 90 percent of my music just gets reinforcement from it, but I do like to "feel" the bass a bit on certain synth tracks and some of the more bass heavy reggae.
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Old 12th September 2011, 10:41 PM   #10
bjorno is offline bjorno  Sweden
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Quote:
Originally Posted by peace brainerd View Post
..Does >10 m/s suggest noise? What is the alternative? Wide slotted port? I'm probably misapprehending this..
Yes, at full in-band power not exceeding x-max: The port air velocity should stay(well) below ~10m/S.

Your right, the alternative is to use a much wider port area,thus a longer port too, slotted or not. Rec. always use a port-area in the vicinity of driver Sd/3 or larger.

b
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