Orion with 12 inch woofers

[rt_jensen]

All,

Has anyone built Linkwitz's Orion speakers with XLS12 woofers instead of XLS10 he prescribes?
I am considering building the Orions, but have read that some people feel the XLS10s are a bit limited in the lowest frequencies. First of all, is that a common understanding, or a view of the minority?
Fixing the "problem" could be done by adding subwoofers to tackle f < 40 Hz. SL proposes an XLS12-based design.
So, why not build the Orion with XLS12s from the start instead?
Has any one done this? Any lessons learned?

Thanks,
Rasmus

[rt_jensen]

PS. Of course replacing the XLS10s with XLS12s does not generate the same frequency response as keeping the XLS10s as dipole woofers and adding a XLS12 as a sealed box subwoofer, but anyway. Looking at the datasheets, the XLS12 is 2dB more sensitive @ ~110Hz, and 6dB more sensitive @ 50Hz.

[Drew Eckhardt]

IMHO A longer throw 12" driver (DPL12, AV12) would only be worthwhile in an MTM configuration (Steve Dodd's Bob is a good example). The 12" XLS shares the 10" suspension and only gains 2.5dB from the extra Sd which isn't worthwhile. A change to 12" with a same-width midrange baffle will change the polar response - narrower than the Orion's would be better. The DPL12 has more distortion than the XLS above 60Hz. Such changes would require cross-over changes. A higher Q sub-woofer driver would also preclude using a 60W amp to force amp clipping before reaching the excursion limits above 22Hz.

Excursion limited dipole output decreases at 18dB/octave below Fequal (.17c/D) which is about 150Hz in the Orion woofer section.

At xmax, the Orion woofers are good for 118dB @ 80Hz, 100dB @ 40Hz, and 82dB @ 20Hz. You get 3.5dB more if you use xsus instead. Midrange xmax limits you to 109dB @ 80Hz. This is either adequite (I built the orions and find them fine for 90dBC rock/techno and orchestral at realistic levels, etc.) or woefully insufficient (full-range reference level home theater needs 115dB for LFE and 105dB for the screen channels. Organ music may also have higher requirements).

A longer throw 12" gets you 5-6dB total. Up top this lets the woofers keep up with the 6dB output increase from a pair of midranges.

A sub-woofer gets you 6dB more output at the cross-over point (106dB with a 40Hz XO, enough to match the midrange). One XLS10 in a sealed enclosure gives you 11dB more at 20Hz in half space. Moving it to a corner gives you even more output - 12dB in theory, maybe 6dB in practice. A box woofer in a typical room gains another 5dB at 20Hz. Obviously you could use other/more drivers for even more output or less distortion.

One dipole alternative that just keeps up with the Orion midrange in the last octave would be a pair of Tumults in a 24" H-frame, costing $2K for the drivers. You could also use a Parthenon for more money. Sealed sub-woofers are less expensive, smaller, and lower distortion from the reduced excursion.

[Drew Eckhardt]

Originally posted by rt_jensen
PS. Of course replacing the XLS10s with XLS12s does not generate the same frequency response as keeping the XLS10s as dipole woofers and adding a XLS12 as a sealed box subwoofer, but anyway. Looking at the datasheets, the XLS12 is 2dB more sensitive @ ~110Hz, and 6dB more sensitive @ 50Hz.

With the woofers in parallel Orion sensivity is approaching 100dB/2.83V/1 meter at the 120Hz cross-over (88dB and change + 6dB for two woofers + 6dB for half space loading -1.8 dB of dipole roll-off). You don't need more.

Down low you're excursion limited so it doesn't matter there either. The low sensitivity can even be regarded as a feature because it allows one to put together a fail-safe system (as in SL's 60W ATI amp) where you get reasonable output AND the amps clip before the woofers bottom.

[ThomasW]

The TC-Sound TC2+ are excellent 12" dipole woofers.

[rt_jensen]

Thanks Drew for your extensive explanation. From what you say, I should be ok with the standard Orion config.
Rasmus

[Malmsten]

Hi,

Has anyone built Linkwitz's Orion speakers with XLS12 woofers instead of XLS10

Here is a link to another Orion project.

http://www.doddsy.net/steve6_008.htm

Have fun reading


Anders

[Malmsten]

oops!

Has anyone built Linkwitz's Orion speakers with XLS12 woofers instead of XLS10

Ok! Sorry for that, the link is not working in my last post you can copy and paste, or try here to this Orion project. Also this could be of interest for you when you are planning to change the size of baffle, or driver.

Best regards Anders

[Drew Eckhardt]

Don Maurer has the most comprehensive dipole baffle width/polar response tests I've seen here:

http://home.pacbell.net/donwm/PrototypeTestResults.htm

Monte Kay has tested a bunch of potentially suitable woofers for distortion and aerodynamic noise:

http://www.mfk-projects.com/woofers.htm

John Kreskovsky has his NaO MTM with larger woofers and a passive mid/tweeter cross-over:

http://www.geocities.com/kreskovs/NaO.html

[rt_jensen]

All interesting stuff, those measurements.
Unfortunately, I don't have neither time nor resources to do that much of DYI, that's why I have to to go with a kit/finished design.

The original question came up after seeing this
http://www.linkwitzlab.com/images/gr...rion-xo-eq.gif
To me, th's a lot of bass equalization, +18dB at 20Hz, so I was just figuring if anyone had modded a kit/finished design using bigger woofers, likely also increasing the baffle size (i.e. depth of H-frame) to get same response with less eq, and in that way increasing the operating region of the speaker.

Regards