# Unibox Enclosure size help ??



## randyc1 (Jul 20, 2011)

Can anyone with Unibox help figure best enclosure size for a Dayton RS180-4 Driver.

Im building a Sealed version of "Monitor Statements", and would like to know best enclosure size for a Sealed version ??

Thanks!


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## Anthony (Oct 5, 2006)

I don't have that one modeled in WinISD (what I use for sub / woofer sections). 

My gut would say 0.3 to 0.5 cubic feet per driver for that size (10 to 14L)

Big, but sealed enclosures that don't have crazy xmax need more volume for the same frequency range.

Good luck.


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## fastbike1 (Oct 28, 2010)

The vented original design is only 24 liters net, you're not going to be able to fit the drivers, mid tunnel, braces etc in a cab much smaller. Why modify a great design?


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## randyc1 (Jul 20, 2011)

fastbike1 said:


> The vented original design is only 24 liters net, you're not going to be able to fit the drivers, mid tunnel, braces etc in a cab much smaller. Why modify a great design?


They will be used for HT, they were designed ported for low bass extension which will NOT be used,since they will be crossed at 80hz with Subs,.. so i might as well designe them sealed to get benifits, the sealed variant will have more accurate, phase coherent bass.


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## fbov (Aug 28, 2008)

If you don't want them ported, exclude the port. 

This is one of the rare designs where all box dimensions have an affect on sound, due to the presence of a mid tunnel that's dependent on depth. You can't reduce height - no room - and width is critical when BSC is applied. The tunnel takes out your last degree of freedon, this side of dense fill, eg. bricks.

That said, Unibox predicts you'll be in a very good spot at 24L - fill will take you from box Q of 0.74 (empty) to 0.66 (heavy fill), allowing you to tune your bass response around the optimally flat Q of 0.707. 

The downside is that 10W at 40Hz will push the driver past Xmax... at 30W it's 70Hz. This most certainly will work in your HT with normal 80Hz cross to subwoofer. I don't see much more to ask for...

HAve fun,
Frnak


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## randyc1 (Jul 20, 2011)

fbov said:


> If you don't want them ported, exclude the port.
> 
> This is one of the rare designs where all box dimensions have an affect on sound, due to the presence of a mid tunnel that's dependent on depth. You can't reduce height - no room - and width is critical when BSC is applied. The tunnel takes out your last degree of freedon, this side of dense fill, eg. bricks.
> 
> ...



Was this modeled with Unibox ??


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## fbov (Aug 28, 2008)

fbov said:


> ...That said, Unibox predicts ...


Roger that.


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## randyc1 (Jul 20, 2011)

fbov said:


> Roger that.


Hmmm ,Mind you i'm a newbie ,but last time i tried moeling that RS 180-4 , i did'nt come to same conclusion , but like I said, i'm very new to all of this ??


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## hdspeakerman (Dec 16, 2006)

http://techtalk.parts-express.com/showthread.php?233564-Unibox-for-Newbies&highlight=Unibox

I stumbled across this unibox guide and it was a lot of help to me. Howard


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## fbov (Aug 28, 2008)

If your results are at odds with someone else's, post them and let us take a look. It's not hard to mis-enter T/S parameters... just did that today, in fact. Having built RS180-base vented MTMs, I don't think I'm far off, but I used 8 ohm versions so data entry errors for the 4 ohm are possible in my analysis, too. 

Have fun,
Frank


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## randyc1 (Jul 20, 2011)

fbov said:


> If your results are at odds with someone else's, post them and let us take a look. It's not hard to mis-enter T/S parameters... just did that today, in fact. Having built RS180-base vented MTMs, I don't think I'm far off, but I used 8 ohm versions so data entry errors for the 4 ohm are possible in my analysis, too.
> 
> Have fun,
> Frank


I dont have Excel2000 on my home computer ,only at work ,but i took a picture ,you cant see the F3 but it is at 52hz for a (20L) sealed box . If i remember correctly (24L) F3 was around 51hz !


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## fbov (Aug 28, 2008)

"Print Screen" and "Paste" are your friend...

Using the same spec sheet data, I get the same as you, to within the least significant digit. I get 52.97Hz as an F3. 24L is 51.5Hz. This is well beyond "close enough."

Have fun,
Frnak


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## randyc1 (Jul 20, 2011)

fbov said:


> "Print Screen" and "Paste" are your friend...
> 
> Using the same spec sheet data, I get the same as you, to within the least significant digit. I get 52.97Hz as an F3. 24L is 51.5Hz. This is well beyond "close enough."
> 
> ...


Yes that is excactly what i get !

...In the Picture,..Is the Recommende box size (40,6L) ?, can that be right ??


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## fbov (Aug 28, 2008)

Yep, recommended box size is 40.6L... based on what criteria? Qtc

Qtc of 0.707 (or 1/sqrt(2)) gives an optimally flat LF response with a 12dB/Oct roll-off, and the only non-driver parameter is box size. It may not be optimum overall, but it's not a bad place to start. 

"Recommended" also assumes an empty box, and adding fill drops Qtc, so you can get to 0.7 with less internal volume by adding fine fibers that make the box "seem" bigger in terms of driver response.

Have fun,
Frank


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## randyc1 (Jul 20, 2011)

I just realized that the Rs parameter under External Components is at 0.8 ... When put at 0 i get a suggested Vb of 18L 

What value should Rs be at ???


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## fbov (Aug 28, 2008)

Rs is all the resistance in the connections - speaker wire. I use 0.2 ohms, but even that value is a little high when the plate amp's only a foot away.


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## randyc1 (Jul 20, 2011)

How about the crossover , i heard that adds resistance also ?


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## fbov (Aug 28, 2008)

You're not going to beat Jeff's answer...
"I recommended a generic value of .6 Ohms for crossover and speaker wire resistance if you are using a passive crossover. Of course, you can look up actual DCR values if you know the inductors you are going to use, and you should include about .1-.2 Ohms for speaker wire as well. If you are using a plate amp in the enlcosure then leave this cell blank. "

So the answer is that it depends, unless you're talking subwoofers, the it's 0. Look at the woofer's XO and see if there's a coil in series, and its DCR value. Use that plus 0.1ohm for wire. My mains are all capacitive loading, but my CC has a coil in series...

HAve fun,
Frank


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## randyc1 (Jul 20, 2011)

Thanks fbov !!


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