Picture and question

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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

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pinkmouse said:
Surely not a push/pull configuration, Dave?:D :D :D

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
 
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Jean said:
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
 
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Jean said:
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
 
planet10 said:


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?



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

dave

WinISD shows Q of 0.5 for top cabinet and -3db point of around 80hz.

Single 10" side firing (peerless csx 10" or vifa 26w), depth of the cabinet is 12" so they will fit but not going to look pretty (I am not sure about the looks).

I think I might just port the top and leave it at that. WinISD shows 2" port tube about 7" long will give me -3db point somewhere around 40-45hz.
 
navin,

how big of a box did you use with m26? I am just thinking about what I want to do next and what drivers to use.

Maybe 3/4" ss tweeter + 8640 mid + something for bass :) I am not sure yet if I want to tackle a 3 way w/o any measuring software/tools. Maybe a 2 way (with smaller mid for better midrange) on one amp, and then bass cabs on another amp with active xo.
 
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