# New CSS Trio12/BASH 500 Sub DIY - WinISD Questions



## Doug_MN (Aug 12, 2011)

New guy here. I've been studying the wealth of info on this forum (long time listener, first time caller!) and I'm gearing up to build a ported, 6 ft^3 sub using a CSS Trio 12 and a BASH 500 amp. I've modeled many different options with WinISD Pro and I believe I'm ready to build. Before the sawdust flies, I'd like to ask a few questions about my understanding of the model results and real world usage.

Background: I'm building a triangualar shaped enclosure to fill a corner space behind a sectional couch. With a 12" downfiring orientation, I can tolerate a 6 ft^3 air volume. Usage is 90% HT, 10% music. Room is ~14' x 25'. 

The BASH amp provides a table of Bass Boost values that provide both a boost at a particular frequency range but also provide a HPF. I'm linking to WinISD screenshots showing the cone excursion at 350W signal power. I also show the filters I've modeled. 

Link to WinISD Xfer Function of CSSTrio12: http://imgur.com/2XCYf
Link to Cone Excursion: http://imgur.com/V75Ob

*Question* - Did I model these BASH filters correctly?
*Question* - If I build the sub with these predicted results, am I in trouble with cone excursion?
*Question* - Knowing this sub will see 90% HT usage, is it reasonable this sub will see 350w? 
*Question* - If 350w is not reasonable, what is a realistic wattage to model?

I've also attached the WinISD wpr file of this model and I'd love for any of you wizards to critique my work. I haven't cut any wood yet and now is a great time for corrections or improvements.

Thank you kindly in advance for your support!

Doug


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## Mike P. (Apr 6, 2007)

Green is your model. The 13.9 HPF will cause the sub to bottom out at the lower frequencies.

Orange is HPF at 18.7, 1 db of boost at 27.5 Hz (middle of the boost range), input power 500 watts which isn't a problem for the sub. Increase the height of the port to 1.5".


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## Binary (Nov 23, 2009)

Can't argue with mike P, unless you want to build one of them Monster Horns that are listed on the CSS home page. If you want one of those, im sure you won't be disappointed. :devil:


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## Doug_MN (Aug 12, 2011)

Mike,

I was hoping you'd reply. I must be doing something wrong in WinISD. When I model the 1dB, 18.7 Fc at 27.5 hz center frequency I get a much bigger rolloff in the transfer function plot. I can't get my curve to match yours. Any chance you could either screen shot the filter settings you used or show me the wpr file? I've been doubting my filter settings in WinISD.

Thank you!

Doug


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## Mike P. (Apr 6, 2007)

The HPF and boost filters are separate. Here's the file:

View attachment Doug TRIO12.wpr


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## Doug_MN (Aug 12, 2011)

Mike,

Thanks for the wpr file - this helps. One question about your vent suggestion of 1.5" wide versus my planned 1.25". How much impact on vent noises will the 0.25" make? The reason I ask is my design makes it pretty difficult to open the vent to 1.5".

Thanks!

Doug


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## Mike P. (Apr 6, 2007)

1.25" will be fine, airspeed is under 26 m/s. Just make sure you round over all the corners and edges.


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## Doug_MN (Aug 12, 2011)

Mike,

I'm finalizing the box dims and I'm finding a 5 ft^3 box has a better WAF and aesthetics for the room. The screen shot shows an SPL comparison between the 5 ft^3 and 6 ft^3 box. With ~0.8 dB difference at 20hz, I'm wondering how noticeable would be. Can you help me understand if this difference could be heard/felt in a side-by-side comparison? Any other thoughts or considerations for this difference?

Thank you,

Doug


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## Mike P. (Apr 6, 2007)

You wouldn't notice the difference, port length is a bit longer.


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