Anyone heard the extremis in a small sealed enclosure?

cjh

Member
2003-01-20 11:27 pm
St. Louis
I'm thinking of buying a pair of Adire extremis drivers to use in a new pair of HT mains. I've read a lot of good things about the Kit 61's and the Kit 261's, but has anyone heard these speakers in their (very small) recommended sealed enclosure of 9.5 liters? How much bass quantity would I be giving up versus the 21 liter ported? This driver is supposed to prefer a vented alignment, so would the quality of the bass suffer as well?

I know a 21 liter enclosure is not very big, but the idea of some VERY small mains appeals to me due to space constraints near my TV.

Would the crossover from the kit 61's need to be modified for a sealed enclosure?

CJH
 
Putting it in the recommended sealed enclosure will raise the F3 up a good octave, from ~35hz to ~70hz. You'll lose a good bit of low end by going sealed with it, and above ~200hz the efficiency difference between the ported and sealed alignments should be very similar, so I don't see there being a problem with the crossover. It would be a good idea to email their tech support about it though, Dan and Steve have been very helpful in the past when I've asked questions.
 

SpeakerBob

Member
2002-08-15 6:21 pm
UK
Going sealed may actually help if you're planning on doing 'the usual' home theater setup : ie setting your mains to small and crossing at 80Hz to a sub.

~Most~ av receivers put a 12dB high pass on the mains, and a 24dB lowpass on the sub. Sealing the mains will give a 12dB high pass at near enough the right freq to add to the receivers slope to make the correct 24dB high pass for your mains.

Hope that made sense:D

Rob
 
I've only used my extremises in vented, aperiodic, and transmission line enclosures.

The vented boxes I used were .5cubic feet tuned to 30hz. I'd say the F3 was somewhere near 40hz but usable response down to 30hz(in room). When I stuffed the ports on those and made them aperiodic they honestly didnt sound incredibly different. The were a bit weaker on the low end though and 40hz was surely end of usable output. Now in my TL's, they sound about the same as the aperiodic as far as LF cutoff. But I'm using very small lines which are heavily stuffed.
 

cjh

Member
2003-01-20 11:27 pm
St. Louis
Thanks for the helpful replies so far. One more question...

Since the f3 will be moved up and an octave and the small sealed box would pressurize very much for really low freq's, would I really just be wasting a lot of the x-max of this driver without a really powerful amp to drive them. (I have 100 watts per channel).

CJH
 
sr20dem0n said:
Not sure what you mean exactly, within an octave of tuning the cone will be moving much more in a sealed box than it will in a ported box. Below this the ported setup will unload and start moving a lot more than the sealed setup, and above this their excursions will be roughly similar.


Oh yeah, I forgot that sealed enclosures make the cone move more than ported ones down low. I had it backwards...
 
dvdvideo said:
Why not just use the wr125s driver instead, stay small, and save money as well.....


:smash:

I can understand getting the Extremis and experimenting with different sizes or types of enclosures, but if you really need to use a small enclosure, you are just wasting the ability of the Extremis (or any mid-size woofer, really). The wr125 seems better suited to the job.
 
Variac said:
But right around where the port augments tuning the cone moves very little, so ported have less excursion until below the tuning and the go berserk. (actually - "goes berserk" is quite an exageration with normal music!

Ported woofers go berserk when playing LP's if there's no infrasonic filter in the preamp.

sbolin said:

I can understand getting the Extremis and experimenting with different sizes or types of enclosures, but if you really need to use a small enclosure, you are just wasting the ability of the Extremis (or any mid-size woofer, really). The wr125 seems better suited to the job.

The Extremis would go to about 70Hz sealed, vs 90 for WR125, which is significant. But there would be a major difference in bass quality aside from the extension. The Extremis moves a lot more air, which is critical to good bass, and would have lower distortion at low frequencies.

And a sealed Extremis would be better than ported if matching to a sub.