I want to make my own center channel speaker and i am un sure of how to figure out what size enclosure is best for my speakers! I have the following components:
Goldwood GW-204/8S (X2)
*Power handling: 40 watts RMS/70 watts max *Voice coil
diameter: 1" *Le: .2 mH *Impedance: 8 ohms *Re: 7.3
ohms *Frequency range: 100-10,000 Hz *Fs: 138 Hz *SPL:
83.5 dB 2.83V/1m *Vas: .035 cu. ft. *Xmax: 1.5 mm
*Qms: 6.81 *Qes: 2.02 *Qts: 1.56 *Dimensions: Overall
Diameter: 4-1/2", Cutout Diameter: 4", Mounting Depth:
2-9/16".
Tang Band (TB) 28-847SE
Specifications: Power Handling: 80 watts RMS/120 watts
max *VCdia: 1-1/8" *Impedance: 8 ohms *Re: 6.0 ohms
*Frequency range: 1,500-25,000 Hz *Fs: 850 Hz *SPL: 90
dB 2.83V/1m *Dimensions: A: 2-7/8", B: 2", C: 1-7/8",
D: 1-7/8"
2500Hz crossover
is the VAS the size the box needs to be? do I double it for using two woofers?
Thanks,
chuck
No the VAS is not the size of the box. It is the volume of air the had the same "spring compliance" as the driver suspension. However you are asking for help after buying drivers. Bad plan.
How are you planning to use these drivers? Lay out I mean. The outlook for your woofers looks unpromising. The F3 is 138 Hz. The Qts is 1.56 so the enclosure will have to be sealed. The F3 will end up well north of 150 Hz. I can model these drivers if you want, but I fear I'm wasting my time. The sub will have to crossover far too high.
What crossover are you using? You can not use generic crossovers. Every crossover has to be custom designed and built for the speaker.
Is there any chance we can start again and select some more promising.
drivers? We can then help guide you through the design and build.
What are you using for mains, so we can try for a good match? Also what is your space. If you can avoid the usual MTM layout placed 90 degrees off axis that would also help.
I have a feeling those woofers are for auto use. Am I correct?
OK. I took pity on you and modeled this driver for you. It is close to how I guessed it. This must be an auto woofer designed for open baffle.
Your closed box alignment has an F3 of 138 Hz. Too high. Worse the Qtc is 1.51. There is a 3db rise centered at 250 Hz. A speaker with a Qtc over 1 will be boomy. Optimal range is 0.5 to 1.0.
I did model it as a ported enclosure, but the enclosure ends up on the large size. There is a whopping 7 db peak centered at 175 Hz.
A speaker built with these drivers will have lousy speech clarity. Speech will have a nasty chesty quality. Sorry your plan is not worth the effort.
I strongly encourage building speakers, but I need a member to ask for help before he has the bits! Proper driver selection for the goal you set is the start of the process.
Can we start with a clean slate?
Here is your sealed alignment for two woofers.
Name: GW-204-8S [2005]
Type: Standard one-way driver
Company: Goldwood
No. of Drivers = 2
Mounting = Standard
Wiring = Parallel
Fs = 138 Hz
Qms = 6.81
Vas = 0.991 liters
Xmax = 1.5 mm
Xmech = 2.25 mm
Qes = 2.02
Re = 7.3 ohms
Le = 0.2 mH
Z = 8 ohms
Pe = 40 watts
Qts = 1.56
no = 0.124 %
1-W SPL = 83.09 dB
2.83-V SPL = 83.5 dB
-----------------------------------------
Box Properties
Name:
Type: Closed Box
Shape: Prism, square
Vb = 0.0515 cu.ft
Qtc = 1.451
QL = 20
F3 = 142.2 Hz
Fill = heavy
Here is your ported alignment.
Name: GW-204-8S [2005]
Type: Standard one-way driver
Company: Goldwood
No. of Drivers = 2
Mounting = Standard
Wiring = Parallel
Fs = 138 Hz
Qms = 6.81
Vas = 0.991 liters
Xmax = 1.5 mm
Xmech = 2.25 mm
Qes = 2.02
Re = 7.3 ohms
Le = 0.2 mH
Z = 8 ohms
Pe = 40 watts
Qts = 1.56
no = 0.124 %
1-W SPL = 83.09 dB
2.83-V SPL = 83.5 dB
-----------------------------------------
Box Properties
Name:
Type: Vented Box
Shape: Prism, square (optimum)
Vb = 1.026 cu.ft
Fb = 88.93 Hz
QL = 6.998
F3 = 72.39 Hz
Fill = minimal
No. of Vents = 2
Vent shape = round
Vent ends = two flared
Dv = 4 in
Lv = 4.922 in
