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Old 13th July 2003, 04:53 PM   #1
VEC7OR is offline VEC7OR  Lithuania
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Question I'm planning to biuld a sub

My system lack some punch from below so I desided to build a sub myself(PA and carpentry included in hand.sys and brains.dll ) I'm looking forward to buying these drivers Visaton W 200 S 4 Ohm or W 250 S 4 Ohm
both of them are siuted for vented boxes, so I decided to biuld a bandpass sub. These drivers are siuted for vented box, simulation shows that they will normally perform in a bandpass as well.
The only problem I'm aware of is port noise... tuning this baby fairly low(17-20- - -50-60hz) means big vents, while bigger vent mean longer vents...
I dont expect much SPL, but I do want my furniture to shake
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Old 14th July 2003, 01:40 AM   #2
OMNIFEX is offline OMNIFEX  Jamaica
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So What's The Question Dude?
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Old 14th July 2003, 05:57 AM   #3
VEC7OR is offline VEC7OR  Lithuania
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Wont the vents make noise from air movement at low frequency ??? (SS and BassBox suggest bigger vents - which means they are longer)
Vent resonants start somewhere at 200+ Hz, that Okay, my mids take it from 60-70, I'll be using and amp + electronic crossover.
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Old 14th July 2003, 10:43 PM   #4
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keep airspeed below 5% of speed of sound'

and yes bigger means longer..but if you tune slightly higher,it shouldnt be too bad.

you could go PR if you have to,or use a Large box subwoofer,

eg a shiva instead of a XLS peerless
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Old 15th July 2003, 12:06 PM   #5
VEC7OR is offline VEC7OR  Lithuania
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Talking The Driver

Visaton W200S

Nominal power handling
75 Watt
Peak power handling
115 Watt
Nominal impedance
4 Ohm
Frequency response
fc - 5000 Hz
Mean sound pressure (nominal)
88 dB (1 W/1 m)
Maximum cone displacement
20 mm
Resonance frequency fs
30 Hz
Magnetic induction
1,1 Tesla
Magnetic flux
600 Weber
Height of front pole-plate
5 mm
Voice coil diameter
3,5 cm
Height of winding
1,2 cm
Cutout diameter
18,4 cm
Net weight
1,5 kg
D.C. resistance Rdc
3,7 Ohm
Mechanical Q factor Qms
3,47
Electrical Q factor Qes
0,33
Total Q factor Qts
0,3
Equivalent volume Vas
65 l
Effective piston area Sd
214 cm2
Dynamically moved mass Mms
28 g
Force factor Bxl
7,7 T m
Inductance of the voice coil L
1,5 mH
Attached Images
File Type: jpg driver-(w200s).jpg (41.4 KB, 914 views)
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Profanity took a very interesting form in Russia where there exists a language of sorts, most of its words based on four basic profane roots - nouns p...is, wh.0.e, c..t and verb f..k. It is possible to sensibly communicate using just these four basic roots.
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Old 16th July 2003, 11:44 AM   #6
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the main ones are Fs ,Qts ,(Qes, Qms) Vas, Xmax, and Efficiency.


what is the purpose of the woofer-music or hometheatre?

www.linearteam.dk for winisd pro



ok i wasnt sure what exactly you want-but heres what i did in win isd. (for music)

-=-=-=-=-=-=-=-
35L 38hz tuned
3inch pipe 21.4cm long or 4inch pipe 40cm long.

Group delay only 15ms
you can tune lower if you want to,its just that its a small speaker so dont want to stress it for no reason.
-=-=-=-=-=-=-=-
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Old 17th July 2003, 11:43 AM   #7
VEC7OR is offline VEC7OR  Lithuania
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After braggin with designs and box volumes, best results are with vented box with active subsonic filter and 6 order parallel bandpass(Mr B##e's one )
The Vented:
Box - 30l
Vent - 30Hz
Subsonic - 32Hz 12Db/Oct
Q ~ 1,93
vent ~ 10cm diam. ~70cm
vent air speed ~ 17m/s max
group delay 17msec max
-2,5db at 29hz
108db at 115W at 30hz

The Bandpass:
Box1 - 35l
Box2 - 12l

Vent1 - 32hz
8cm - 40cm - 14m/s max
Vent2 - 70hz
10cm - 25cm - 10m/s max

max group delay 20msec
-3,5db at 29hz
105db at 115w at 30hz

Bandpass vs Vented
BP pros - shorter vents, no subsonic filter needed, better control over cone movement
cons - bigger box, bit lower SPL, bit bigger group delay(no bumps tho)

VB pros - high SPL, smaller box, smaller group delay
cons - needs subs filter, big vent needed to prevent port noise

I'm looking forward bandpass - fitting 80 cm 10cm diam. tube into 30l box is not for me. I listen mainly to jazzy/deep house/dub music so "slow" bass isnt a big issue for me.
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Profanity took a very interesting form in Russia where there exists a language of sorts, most of its words based on four basic profane roots - nouns p...is, wh.0.e, c..t and verb f..k. It is possible to sensibly communicate using just these four basic roots.
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Old 17th July 2003, 09:05 PM   #8
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bandpass has worser sound,worser transient response

Quote:
cons - needs subs filter, big vent needed to prevent port noise
any port will have to be big if your tuning 30hz in 30L!

i suggested my tuning,which is higher,to avoid long ports



Quote:
fitting 80 cm 10cm diam. tube into 30l box is not for me
it is for NO one because when you calculate the box volume,the port doesnt count,so you may have a 30L box+ 8Litre port.

so make a compromise-increase tuning frequency slightly,and slightly increase box size to make port shorter also,without changing response too much
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Old 20th July 2003, 11:36 PM   #9
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I've made up my mind(after long time searchin the net :tired - I'm going for 6 order parallel bandpass, the points:

1) Simple vented box, even lower tuned (EBR), lags more - up to 30ms delay thats sure leads to "slow" bass

2) bass response: -3db at 35hz siuts me just fine(I expect room gain somewhere near 35-40hz, stuff gets boomy there, tested by 2 subs and 6 ears)

3) keeping air speed in vents at max of 16ms/s (0,047(5%) speed of sound, though most sites recommend 5-10% ) ports are fairly short ~40cm and ~ 20cm - easily fitted into the box

4) group delay no bigger than 16ms(sealed boxes have max of 4-8ms, posted up to 50(thats poorly designed, BTW extended bass response vented enclosure has delay up to 40ms - thats a ), most sites say that anything 10-20 ms is okay)

The graphs:
Attached Images
File Type: gif bandpass.gif (26.4 KB, 771 views)
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Profanity took a very interesting form in Russia where there exists a language of sorts, most of its words based on four basic profane roots - nouns p...is, wh.0.e, c..t and verb f..k. It is possible to sensibly communicate using just these four basic roots.
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Old 28th July 2003, 08:22 PM   #10
VEC7OR is offline VEC7OR  Lithuania
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Materials question - whats better - 12mm plywood(may be doubled) or 16mm(can be doubled) MDF ???
Or I should use double plate for driver mount only ? (box would be approx 33x44x74cm with driver in the middle and 1more brace)
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Profanity took a very interesting form in Russia where there exists a language of sorts, most of its words based on four basic profane roots - nouns p...is, wh.0.e, c..t and verb f..k. It is possible to sensibly communicate using just these four basic roots.
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