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Old 26th July 2008, 12:04 PM   #1
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Default DIY 1st timer: Please help the noob.

Hi everyone,

I've decided to take the plunge into diy I have bought a pair of Peerless India 3" fullrange drivers and a pair of 8" woofers ( S20NISH-08) http://www.peerlessaudio.com/product...3.asp?pname=17

Now I'm stuck at the designing stage

I used WinISD Pro, and entered the parameters for the 8" as given in the help, but I keep getting a "Divide by zero" error. I also tried speaker workshop, but couldn't quite figure it out. Is there any other software I could try?

Have any members from India used this woofer? I think I need Sd, Hc and Pe values for WinISD to work.

Also, I can't decide whether to go for 2 sealed boxes or one isobaric box. What are the comparative pros and cons? My room size is 9.5x12.5x8.75 (WLH)

TIA
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Old 26th July 2008, 01:29 PM   #2
Ron E is offline Ron E  United States
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Sd = S = 230.58 cm^2 or .023058 m^2
Pe = Pi - not specified - you can guess, maybe 50-100Watts
Hc = height of coil, not specified
( Hc(oil)-Hg(ap) )/2 = xmax, for a nonspecific 8" woofer you might guess that Xmax is 3-5mm - so Hc is 11-15mm (probably at low end of this range)

Try entering only the following parameters into the parameter sheet (watch out for units)
Fs
Qes
Qms
Cms
Sd
Re
Pe
Xmax

Then let the program calculate the rest and don't be too concerned if the calculated values are a little different than your spec sheet. It is fine to put in a guess value on the last two in my list, it does not affect box volume calculation, it only affects port design and max output.

[edit .. if you try this and still have problems entering parameters , post a screen shot of what you are entering]
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Old 26th July 2008, 02:10 PM   #3
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Thanks for the fast reply I'll try this out and report back.
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Old 27th July 2008, 02:31 PM   #4
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Ok that worked I'd mixed up some of the units earlier.

Any suggestions regarding 2 sealed boxes vs a single isobaric box?
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Old 27th July 2008, 05:47 PM   #5
Ron E is offline Ron E  United States
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Well, the decision is between space or performance.

You will get more SPL out of 2 separate woofers - you might save a little space with an isobaric, but you will get less output. It's your decision.
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