Picture and question

[Jean]

Hello,

I am looking for input on turning a 2way into a 2.5 way. Here is a picture of my unfinished speakers. The top cabinet is SS9500 and PL18wo in 18liter sealed (at the moment) cabinet. Bottom part is a speaker stand that I am thinking about adding another midbass driver to.

Would it be okay to run TM sealed and the .5 woofer ported ? I just want to increase bass response a little bit and take care of BSC.

thanks

[Westrock2000]

Nice job

Sorry it's not an answer, but its a TTT (to the top)

[planet10]

They should both have the same low end phase response (otherwise as they move out of phase they will start cancelling) so they are both best seled. And i'd put the 2nd woofer on the back.

dave

[pinkmouse]

Surely not a push/pull configuration, Dave?

[planet10]

Originally posted by pinkmouse
Surely not a push/pull configuration, Dave?

You could do... but for something up into the midrange (Jean, how wide is the box?) i wouldn't really want the frame exposed to generate noise. And without doing fresh cabs he couldn't do push-push.

Jean, Is the bottom part completely separate (ie a stand) or integral? If separate you could try it front facing or rear facing.

I like rear facing becuase then you can "hide" the back driver from the front during the part of its phase response where it rolls thru 90 degrees (from the 1st order filter used to make it a 0.5 speaker) keeping things a bit more seemless.

dave

[Jean]

Planet10, external width is 9.5" , internal is 8.5". Second cabinet
is seperate from the TM. So even if the 2nd woofer will be rolled off at 200hz or so they are better off sharing the same air space ?

Here is internal shot of the TM, showing its brace.

[Jimmy154]

The dude at this link http://home.hetnet.nl/~geenius/Auriga.html makes a 2.5-way with the midrange sealed and bass ported.

[planet10]

Originally posted by Jean
[B]Planet10, external width is 9.5" , internal is 8.5".

That puts the theoretical bafflestep -3dB point at 480 Hz. That is your starting point for rolling off the bottom woofer.

Second cabinet is seperate from the TM. So even if the 2nd woofer will be rolled off at 200hz or so they are better off sharing the same air space ?

They don't have to share the same airspace, but should have the same roll-off characteristics. So in your case the 2nd woofer should be sealed and in the same size enclosure(slightly larger is probably OK).

With them seperate you can try both front facing & rear facing to see which integrates better (your room and speaker placement in it will have an effect).

dave

[Jean]

Planet10, I guess I was hoping to have my cake and eat it too Sealed top cabinet for quick midbass response and ported bottom driver to extend the bass.

Have you used vifa m(or p)26w 10" woofer before ?

[planet10]

Originally posted by Jean
Sealed top cabinet for quick midbass response and ported bottom driver to extend the bass.

It would be nice, but the physics aren't one dimensional, we have to consider the phase.

What do you estimate the Q of the sealed box to be?

Have you used vifa m(or p)26w 10" woofer before ?

Just the P13 and i have a batch of P17s OEMed for PSB. The 10" units that ApexJr have are very tempting thou.

dave