Slim 3 way: extremis for the bass, or is there a better choice?

[Drew]

I'm currently (seemingly perpetually) in the design phases of a 3 way. For domestic tranquility, the speaker should be fairly slim (~8").

I was originally hoping to use a Dayton 10" HiFi sub in a side firing configuration, with a peerless 850439 as the mid. Unfortunately, the HiFi won't go low enough sealed and a vented box is too big. I don't want to deal with an LT type active EQ circuit.

So, I'm thinking about 2 extremis per side, crossed over at 250-300Hz to either a peerless 850488 or the seas MCA15. This models really well, but I have concerns about the quality of the extremis' bass. Their distortion numbers seem to be only average and 300 Hz is an important area musically - lots of fundamentals in this range.

I've read a lot of complaints about the extremis' distortion numbers at higher frequencies, but for bass duty it's harder to find opinions.

I'm really trying to pick low distortion drivers for this design and use them in their appropriate ranges. Does the extremis fit the bill? Are there better options?

Thanks in advance.

[cjd]

I found the bass of the Extremis to be quite good (Jim Salk's MTM with the Extremis and a ribbon tweet). Not quite as precise as the TC Sounds it was put up against to my ear (which were in a 3-way with a Seas mid and ribbon tweet). But very very good. I would absolutely consider the driver to be a contender.

To my ear, it was just that characteristic poly sound coming through.

What I was not able to tell was whether I actually had any issue at all with the bass performance, or was simply less enamored of its midrange+ performance and this tainted my overall impression. I'm not a fan of poly in my experience.

For your specific set of requirements, you may not find a better option.

C

[Drew]

What I was not able to tell was whether I actually had any issue at all with the bass performance, or was simply less enamored of its midrange+ performance and this tainted my overall impression

Yep. This is what I seem to be running across fairly often in peoples' opinions about the Extremis.

I was hoping to find a good set of measurments, but, while many other drivers have been measured pretty thoroughly, it's slim pickings with the Extremis - particularly measurments at low frequencies. This makes it hard to do an apples to apples comparison against other drivers.

Does anybody else have any thoughts?

[cjd]

http://www.diymobileaudio.com/forum/showthread.php?t=664

And, just for fun, I have actually been considering these of late for a project. :P For low end only. I'm just not enamored of the price at this point. Thinking of trying the 4.5" "full range" driver Adire has done as well, with the OW1.

C

[GrahamT]

The only reasons I can see to use the Extremis is when you need a lot of low end in small, wide-bandwidth two-ways, or when the baffle has to be narrow. If you can afford more space and are crossing low, then larger Sd drivers are the way to go. Hey that rhymed!

They are spendy too, less so up here though.

That said, for my application I couldn't be happier with them. I needed a small, sealed two-way with good low end performance and high output, and low distortion. :T Oh, and I like poly cones, though I should probably not say that 'round these parts. :P

Drew,

There are measurements a-plenty in this thread:

https://htguide.com/forum/showthread.php?t=9891&highlight=adire+extremis

Also Mark K did a lot of testing of 7" drivers, including the Extremis