Want a little extra thump for low budget

[MLA]

That vett box is not deep enough for the RF marine 12", nor is that 1.1 wedge. 

that 2.2 sq is WAY to large. Put a 4" round euro port in that thing!

1.3 ft3 is much better but I like closer to 1.0 ft3.  

[MotoGPTy]

I could be wrong but I'm not sure where 2.2 came from. Specs for QBomb 12 Single (the square one) show "Air Space: 1.3 Cubic Feet"

http://www.qpowerinc.com/index.php?id_product=35&controller=product

 

 

[The Hulk]

can you hear a difference between 1.0 , 1.3, 2.2 ?

i'm probably going to measure what will work and have a custom built sub box: if so what is the "ideal" size?

[MLA]

Yes, you can hear the difference between 1.0 and 1.3 ft3. 

http://www.rockfordfosgate.com/support/knowledge.aspx?kbsrc=http://rftech.custhelp.com/cgi-bin/rftech.cfg/php/enduser/std_adp.php?p_faqid=1191&p_li=&p_topview=1

[David]

Lot's of vague info here. So the Rockford manual states that an internal 1.25 cu.ft. sealed enclosure will provide a loaded Qtc of .82 and that's typically a good sounding 'Q'. However, RF doesn't specify the enclosure as gross or net. So after the driver displacement of 0.25 cu.ft. the target internal enclosure will either be 1.0 or 1.25. The QBomb enclosure dimensions would indicate a 1.43 cu.ft. gross internal displacement, and not 1.3. Given the RF 12" sub T/S parameters, I would run with the 1.43 gross internal enclosure. That would be ideal IMO.

Btw, another bit of vague info is the RF 12" driver displacement of .025 cu.ft. I don't trust that number. 0.15 is more like it. But the same size enclosure as referenced above should do fine.   

The Hulk, on another note, if my memory serves me correct, off state 127, near the Fun Spot, there was a small meat & deli shop that had the world's best ham salad spread and chicken salad. Named Hargers? And is it still open?    

 

Edited October 25, 2016 by David

[minnmarker]

1 hour ago, MLA said:

Yes, you can hear the difference between 1.0 and 1.3 ft3. 

http://www.rockfordfosgate.com/support/knowledge.aspx?kbsrc=http://rftech.custhelp.com/cgi-bin/rftech.cfg/php/enduser/std_adp.php?p_faqid=1191&p_li=&p_topview=1

Some 2" foam building insulation (hard pink stuff) and construction adhesive will take out .2 or .3 ft3 in a jiffy.  Just glue the foam to the back/bottom of the QBOMB.

[The Hulk]

10 hours ago, MotoGPTy said:

I could be wrong but I'm not sure where 2.2 came from. Specs for QBomb 12 Single (the square one) show "Air Space: 1.3 Cubic Feet"

http://www.qpowerinc.com/index.php?id_product=35&controller=product

 

 

Sorry I was accidentally looking at the 15" one

[The Hulk]

7 hours ago, David said:

The Hulk, on another note, if my memory serves me correct, off state 127, near the Fun Spot, there was a small meat & deli shop that had the world's best ham salad spread and chicken salad. Named Hargers? And is it still open?    

 

Yes doing well from what I hear.. there is also a meat deli in Fremont ..old grocery store in the back.. best meat around and better price IMO.. always get my meat there

If your ever in the area next season hit me up for a surf run and I'll grill some steaks! 

[The Hulk]

17 hours ago, David said:

Lot's of vague info here. So the Rockford manual states that an internal 1.25 cu.ft. sealed enclosure will provide a loaded Qtc of .82 and that's typically a good sounding 'Q'. However, RF doesn't specify the enclosure as gross or net. So after the driver displacement of 0.25 cu.ft. the target internal enclosure will either be 1.0 or 1.25. The QBomb enclosure dimensions would indicate a 1.43 cu.ft. gross internal displacement, and not 1.3. Given the RF 12" sub T/S parameters, I would run with the 1.43 gross internal enclosure. That would be ideal IMO.

Btw, another bit of vague info is the RF 12" driver displacement of .025 cu.ft. I don't trust that number. 0.15 is more like it. But the same size enclosure as referenced above should do fine.   

The Hulk, on another note, if my memory serves me correct, off state 127, near the Fun Spot, there was a small meat & deli shop that had the world's best ham salad spread and chicken salad. Named Hargers? And is it still open?    

 

yes i'm also confused on this as well i dont think their instructions make any sense for the Vb vs whats listed and speaker displacement etc.. 

so if i were to have one custom build to fit in my boat should i make the internal of the box 1.0, or 1.3 or 1.4 (before speaker)? 

[David]

Based on the published RF T/S parameters I would go with a 1.4 gross internal which should net you around a 1.25 to 1.27 after driver displacement. That would deliver a loaded 'Q' that will produce a deep and flat SQ response. If after listening for a while, you decided you could sacrifice a bit of low bass extension to get a slightly livelier bass, then you could add a small 0.10 block inside.   

[store934]

I don't know if this changes anything but I have seen a few places that have the M212S4 Rockford sub (assuming that is the same as the PM212S4 used now) with a volume of 0.053 cu. ft.  I am adding it to the thread if anyone is looking for it in the future maybe they will find I here.  It might be more accurate than the 0.258 - 0.26 cu. ft. listed in the manuals.

http://www.rockfordfosgate.com/products/details/m212s4

http://www.rockfordfosgate.com/rftech/box_advisor.asp?locale=en_US&p_status=current&p_units=standard&p_series_id=192&p_item_id=110670