Small passive sub?

GhettoSQ · 18th June 2006, 07:33 PM

OK, now that my big living room sub is complete (and awesome), my little kitchen speakers need some help. I have a speaker terminal and a 200hz passive x-over, and my amp can give me a max of 40W rms @ 4 ohms. What can I do with this? I don't need this bad enough to beg the wife for another amp, nor do I have much space. I think I can fit a 5 1/4" driver in a box, but I've read that passive subs are very hard to get right. What am I looking for? I'm thinking a vented box with a 4 ohm DVC driver, maybe I can get it down to 40Hz or so?

just a guy · 18th June 2006, 07:47 PM

The conditions you have listed are hardly ideal for a sub, but it's possible if you don't have to go too loud or low.

Try a small horn design like the Wicked One or the Table Tuba (with at least 8 inch drivers) to get the most of a small driver with very little power.

Google search will take you right to each of these designs and there are many more horn designs available but a bit bigger, like Cowan Audio's design for 2 10's. Horns are the only way to get satisfying bass with low power.

Cal Weldon · 18th June 2006, 08:32 PM

How big can your box be?

just a guy · 18th June 2006, 10:39 PM

Sorry, I read that wrong. But my answer is the same for mains as well. Small horns are great and there are many designs available for small RLH horns as well that will work great with the power you have. You can even go full range and forget the crossover.

GhettoSQ · 18th June 2006, 11:30 PM

Horns sound great but I don't think I have the space. It would most likely go on top of my fridge with the mains, under a cabinet...about 7.5" high, maybe a foot wide and a foot deep but I can make a little more space there. the Tang Band W5-1138SG goes very low in a small ported box (flat to about 35Hz according to WinISD) but is single voice coil and only 82db sensitivity.

Cal Weldon · 19th June 2006, 12:01 AM

If you think you can squeeze the w6 1139 in there it might do OK. Still low sensitivity though.

GhettoSQ · 19th June 2006, 12:03 AM

weirdly enough it modeled about the same, and actually dropped out a few Hz higher...

I could probably fit a 6-1/2" woofer though.

GhettoSQ · 8th July 2006, 08:30 PM

Sorry to dredge up this old thread but I wonder how a sonotube would compare to a ported box for efficiency?

dangus · 8th July 2006, 11:13 PM

Should be the same, assuming the sonotube was used as a ported box.

GhettoSQ · 9th July 2006, 12:22 AM

I was thinking of a TL, sorry for the confusion...

18th June 2006, 07:33 PM	#1
GhettoSQ diyAudio Member Join Date: Feb 2005 Location: Boston, MA	Small passive sub? OK, now that my big living room sub is complete (and awesome), my little kitchen speakers need some help. I have a speaker terminal and a 200hz passive x-over, and my amp can give me a max of 40W rms @ 4 ohms. What can I do with this? I don't need this bad enough to beg the wife for another amp, nor do I have much space. I think I can fit a 5 1/4" driver in a box, but I've read that passive subs are very hard to get right. What am I looking for? I'm thinking a vented box with a 4 ohm DVC driver, maybe I can get it down to 40Hz or so? __________________ GhettoSQ Somewhere between Craft and Kraft

18th June 2006, 08:32 PM	#3
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	How big can your box be? __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

18th June 2006, 11:30 PM	#5
GhettoSQ diyAudio Member Join Date: Feb 2005 Location: Boston, MA	Horns sound great but I don't think I have the space. It would most likely go on top of my fridge with the mains, under a cabinet...about 7.5" high, maybe a foot wide and a foot deep but I can make a little more space there. the Tang Band W5-1138SG goes very low in a small ported box (flat to about 35Hz according to WinISD) but is single voice coil and only 82db sensitivity. __________________ GhettoSQ Somewhere between Craft and Kraft

19th June 2006, 12:01 AM	#6
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	If you think you can squeeze the w6 1139 in there it might do OK. Still low sensitivity though. __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

19th June 2006, 12:03 AM	#7
GhettoSQ diyAudio Member Join Date: Feb 2005 Location: Boston, MA	weirdly enough it modeled about the same, and actually dropped out a few Hz higher... I could probably fit a 6-1/2" woofer though. __________________ GhettoSQ Somewhere between Craft and Kraft


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18th June 2006, 07:47 PM	#2
just a guy diyAudio Member Join Date: May 2006	The conditions you have listed are hardly ideal for a sub, but it's possible if you don't have to go too loud or low. Try a small horn design like the Wicked One or the Table Tuba (with at least 8 inch drivers) to get the most of a small driver with very little power. Google search will take you right to each of these designs and there are many more horn designs available but a bit bigger, like Cowan Audio's design for 2 10's. Horns are the only way to get satisfying bass with low power.

18th June 2006, 10:39 PM	#4
just a guy diyAudio Member Join Date: May 2006	Sorry, I read that wrong. But my answer is the same for mains as well. Small horns are great and there are many designs available for small RLH horns as well that will work great with the power you have. You can even go full range and forget the crossover.

8th July 2006, 08:30 PM	#8
GhettoSQ diyAudio Member Join Date: Feb 2005 Location: Boston, MA	Sorry to dredge up this old thread but I wonder how a sonotube would compare to a ported box for efficiency? __________________ GhettoSQ Somewhere between Craft and Kraft

8th July 2006, 11:13 PM	#9
dangus diyAudio Member Join Date: May 2004 Location: Vancouver Island	Should be the same, assuming the sonotube was used as a ported box.

9th July 2006, 12:22 AM	#10
GhettoSQ diyAudio Member Join Date: Feb 2005 Location: Boston, MA	I was thinking of a TL, sorry for the confusion... __________________ GhettoSQ Somewhere between Craft and Kraft

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