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Discussion Starter · #1 ·
Hello, I have decided to upgrade my current sonosub style sub (not actually made with sonosub tubing, but instead metal ductwork tubing) by getting rid of my current av15x and replacing it with a Fi Q18. I then decided that I might as well have two and have them in the back corners of the room behind the sofa. Going to power them with an EP4000. My current setup is 320 litres effective, with a 14.5hz tune, with 6 inch diameter port. I have used 17.75in diameter tubing which is currently approx 84.5 inches long. Fitting an 18 inch driver into a 17.75 inch tube is not going to be that easy, but as the basket for the driver is about 16.75 inches I'm hoping to just squeeze the basket into the tube with a bit of inventiveness with the endcap. I hope this will work anyway as I haven't actually got the drivers through yet so it is all in my head at the minute!
Anyway, presuming I can get the driver to fit in, what are the opinions firstly on continuing to use the 6 inch port and secondly on keeping the tune at 14.5hz with the same sort of effective volume? I was planning on flaring the port myself. I have managed to source some 180mm (7.1in) diameter port tubing if necessary which drops the volume down to 300 litres dead on. I can fit that if necessary, but I'd like to get away with 6 if poss as I already have that stuff in the garage.
I know most people that use this driver in sonosubs are going with 600 litre designs, but I can't fit that size in the room. The current size of tube is the biggest I can do. The room is pretty small at about 12 x 10 so I'm not really sure how much of the subs potential I'll be using.
Firstly, how are they going to sound with 300 litre volume, secondly is 14.5hz tune still realistic and thirdly will this port size be totally ridiculous even if it's flared?

Any thoughts?

Cheers.
 

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Discussion Starter · #3 ·
Ok thanks, I had thought that probably would be the case to be honest but I was hoping not. I'll get some of the 180mm port tubing in then.
 

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Im going to sound a bit awkward now and I personally would go with a 8" port tuned to 15hz as MikeP says. Port velocity is 30 m/s and if in an event you want to throw more power (and ep4000 to each sub which you can) it will help with the port velocity with the extra power should you want to go that route. Also the first port resonance is 143hz which is all good.

cheers

Graham
 
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