F20 question

[Turbox]

so, I've started my F20 build. which is really 18.5 inches width. 3/4 inch ply on each side brings the width to 20 inches, hence the F20. In another thread we were discussing potentially bringing the width of the F20 to either 24 or even 30 inches. this would allow a better and more efficient response at the lower end of Fc low. So I've started my build. I've decided to build an f25.5 if I can call it that. 24 inches inside horn width, with 3/4 inch ply on each side. F25.5. I decided on using 24 inches rather than 30, because that is the most efficient use of three sheets of plywood. a 30 inch unit would have left me with to much wastage. I am using the Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm. One of the baddest @ss woofers I've seen in a long time. I bought two of these a while ago for a dual F20 build. which might turn into a dual F25.5 build. Its a pretty easy build really, just takes some time, that's all. and im not in a rush. I ran all the plywood through the table saw to get everything the same width. so no issues there.

 

My question is, with the wider width, could I have used Dayton Audio RSS460HO-4 18" Reference HO Subwoofer 4 ohm and been able to get a better response? 18 inch rather than a 15 inch. Theres no turning back now, but i would figure that the 18 inch driver might give a better response? and move more air?

[Scrappydue]

I was always told the rule of thumb for the exact same model is that it would take dual 15's to move the same air as a single 18. So since you are experimenting anyways you prolly should have went bigger. Would have matched the 1802 anyways then!

[Thaddeus Smith]

Which "f20" are you building? My lil' Mike cinema f-20 is named as such due to the 20hz lower limit and its dimensions are precisely calculated towards that goal. If you're building the same one I would be careful about arbitrarily changing dimensions and drivers.

If it's a different one, have at it and maybe share a reference build thread link?

[jason str]

Turbox, use the recommended 15" driver.

[mustang guy]

The HF will provide better response. The HO is a higher output and will not give as low a frequency. Widening the cabinet won't change the characteristics of the tuning, it should flatten the response.

If I am incorrect about any of the above, please feel free to jump in and say so. It won't hurt my feelings or otherwise piss me off.

[CECAA850]

If I am incorrect about any of the above, please feel free to jump in and say so. It won't hurt my feelings or otherwise piss me off.

 

What's the fun of correcting you then?

[CECAA850]

My question is, with the wider width, could I have used Dayton Audio RSS460HO-4 18" Reference HO Subwoofer 4 ohm and been able to get a better response? 18 inch rather than a 15 inch. Theres no turning back now, but i would figure that the 18 inch driver might give a better response? and move more air?

 

Horn subs are like ported subs in that the TS parameters are used heavily when designing the enclosures.  You don't want to arbitrarily start swapping drivers and expect good things to happen.

[Thaddeus Smith]

I'm using the HF and it's perfectly sufficient.

 

http://www.parts-express.com/dayton-audio-rss390hf-4-15-reference-hf-subwoofer-4-ohm--295-468

Edited December 28, 2014 by Thaddeus Smith

[Turbox]

Im using the Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm as well. I stole the idea from a build Carl did. im exepcting good things from this sub.

 

My F20 is 25.5 inches wide and is almost done. I sealed up the cabinet earlier today. Its a fairly easy build, took me about 4 days from start to sealed up. I tell ya. that PL premium is nasty stuff.

[Axz Hout]

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