compact sub - sealed or passive radiator?

Bill poster · 10:58 AM

want to use the Jordan JX150 in two small passive subs (placement either in front of the speakers or both subs can become one unit and slide under sofa).

Not sure which design to go for, PR or sealed.

JX150 has a resonant freq of about 25 hz. I don't mind losing the 3 db that a sealed design would bring as I think the jx150's are about 2db more sensitive than the main speakers.
I would like the drive unit facing towards the floor and was thinking about 40 litres for each sub.

two questions-

if i use a PR (dayton 10 inch)does it matter if the PR is facing upwards are downwards?

If I go for a sealed enclosure would I lose bass extension if the driver is facing towards the floor rather than facing away?

chris661 · 7th June 2010, 04:35 PM

You'll be operating this sub at low frequencies, where output is pretty much omnidirectional. So, in theory, the output will be the same. There's lots of designs out there that use down-firing subs.

What will you be using to drive these?

Bill poster · 11:57 AM

Thanks Chris

using Michell Alecto Monoblocks for main speakers and sub(s).

I'm now looking at two designs (made in corian)-
a one box sealed sub with two jx150s. One 90 litre compartment or separate 45 litre, not sure which is best. This would be slim enough to hide under a sofa or upright against a wall.

Or alternatively two small BR subs using Mivoc drivers placed in front of the main speakers.

Bill poster · 8th June 2010, 12:26 PM

PS crossover around 80- 90 hz 3rd order - main speakers combination of 1st order and acoustic

GM · 8th June 2010, 01:13 PM

Quote:

Originally Posted by Bill poster

I would like the drive unit facing towards the floor and was thinking about 40 litres for each sub.

if i use a PR (dayton 10 inch)does it matter if the PR is facing upwards are downwards?

Hmm, based on published specs this driver's mass/compliance ratio is too great for up-down firing without potential mechanical damage at high excursion. For sure the PR is, so driver on one side, PR opposite side.

GM

Cal Weldon · 8th June 2010, 03:19 PM

Never place the drone cone facing up or down, always place on the side of the box. They sag.

5th June 2010, 10:54 AM	#1
Bill poster diyAudio Member Join Date: Jun 2008 Location: London	compact sub - sealed or passive radiator? want to use the Jordan JX150 in two small passive subs (placement either in front of the speakers or both subs can become one unit and slide under sofa). Not sure which design to go for, PR or sealed. JX150 has a resonant freq of about 25 hz. I don't mind losing the 3 db that a sealed design would bring as I think the jx150's are about 2db more sensitive than the main speakers. I would like the drive unit facing towards the floor and was thinking about 40 litres for each sub. two questions- if i use a PR (dayton 10 inch)does it matter if the PR is facing upwards are downwards? If I go for a sealed enclosure would I lose bass extension if the driver is facing towards the floor rather than facing away? Last edited by Bill poster; 5th June 2010 at 10:58 AM.

7th June 2010, 04:35 PM	#2
chris661 diyAudio Member Join Date: Feb 2008 Location: Lancashire Blog Entries: 7	You'll be operating this sub at low frequencies, where output is pretty much omnidirectional. So, in theory, the output will be the same. There's lots of designs out there that use down-firing subs. What will you be using to drive these? __________________ "Throwing parts at a failure is like throwing sponges at a rainstorm." - Enzo My setup: http://www.diyaudio.com/forums/multi...tang-band.html

8th June 2010, 11:48 AM	#3
Bill poster diyAudio Member Join Date: Jun 2008 Location: London	Thanks Chris using Michell Alecto Monoblocks for main speakers and sub(s). I'm now looking at two designs (made in corian)- a one box sealed sub with two jx150s. One 90 litre compartment or separate 45 litre, not sure which is best. This would be slim enough to hide under a sofa or upright against a wall. Or alternatively two small BR subs using Mivoc drivers placed in front of the main speakers. Last edited by Bill poster; 8th June 2010 at 11:57 AM.

8th June 2010, 03:19 PM	#6
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	Never place the drone cone facing up or down, always place on the side of the box. They sag. __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

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8th June 2010, 12:26 PM	#4
Bill poster diyAudio Member Join Date: Jun 2008 Location: London	PS crossover around 80- 90 hz 3rd order - main speakers combination of 1st order and acoustic

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