12" sealed (sub)woofer for active 4-way recommendations (1 Viewer)

[Todd Shore]

I am looking for recommendations on a 12" woofer to handle the low end in an active 4-way. It will crossover to a pair of Morel MW-164 6.5" midbasses. The Morels' F3 is 59Hz in a sealed enclosure.

This driver should handle 60-80Hz down in a sealed box. Space available for driver is 20 cubic feet. Qtc of the sealed enclosure should be around 7.

I like how a pair of Stryke SAL-SB12's model in 20 cubic feet sealed. F3 is below 27Hz, which is respectable. Efficiency is matched to the Morels, too.

Opinions on the Stryke or suggestions for a better choice?

Thanks.

 

[Hailan R]

damn 20 cubic feet you must not be married or live with your girlfriend(sorry just had to post this)

 

[Todd Shore]

No, I am married. We agreed when we bought this house that the media room was mine.

 

[Dave Milne]

You mean Qtc of about 0.7 (very slightly overdamped)?

It's going to be hard to find a driver in a sealed, unassisted Butterworth alignment that goes "home theater" deep. Since it sounds like you are building a pretty high-end system, you should consider the Tumult with an LT circuit. The box would be much smaller. Needs a fair amount of power, though.

You mentioned 4-way. What midranges and tweeters are you planning to use?

 

[ThomasW]

I am looking for recommendations on a 12" woofer to handle the low end in an active 4-way. It will crossover to a pair of Morel MW-164 6.5" midbasses.....Opinions on the Stryke or suggestions for a better choice

I suggest that you use a midwoofer that has a lower Fs. It's a good idea to to have the LF driver extension to an octave below the intended XO point. That avoids any potential holes in the FR.

Also using a active 4-way, one ends up spending a ton of cash on XO components, amps and interconnects. Most of the time that money is better spent getting higher quality drivers with a wider passband.

Are you custom building the active XO? How are you going to impliment things baffle step compensation, zobels, etc?

 

[Dave Milne]

Or another option might be to use the natural second-order rolloff of the Morels as the crossover or part of the crossover (size the box for Qtc = 0.707 and add a matched second-order active filter for 4th-order Linkwitz-Reilly configuration). However, running the Morels all the way down may limit power handling and maximum output.
You may want to move the XO up an octave as Eggleston does with their Andra II . They run the Morels from 135Hz to 1.8KHz and cross over straight to the tweeter. Kids don't try this at home unless the tweeter XO is at least 4th order and the driver is a bomb-proof Dynaudio Esotar. I'm using the Esotars in my current system at 3K/first order (to a pair of D76 mids in WMTMW config) and regularly run them at Stentorian levels with no problem. I can't say the same about MW164s: I cooked two of them in some MTMs I created some years back (with D28 tweeters).

 

[ThomasW]

Kids don't try this at home unless the tweeter XO is at least 4th order and the driver is a bomb-proof Dynaudio Esotar

Yes one should use higher order XO's to do this. It can be done with great success as low as 1.25kHz with the Vifa XT25 or 1.5 kHz using the a Focal TC120DX2. Either of these tweeters provide stellar performance at relatively modest pricing

 

[Todd Shore]

Dave, I am using the Morel MDM-55 dome midrange and the Hiquophon OW2 along with the forementioned Morel 6.5's.

Yes, Qtc of .7.

 

[Todd Shore]

Thomas, these will be mounted in room integrated enclosures -- part of a projection screen wall. Baffle sizes will be fairly large and baffle step should not be an issue. The diffusion from the missing 4 pi space might be.

I am trying to keep "driver creep" down and change from the drivers I'm using as I don't have any problems with their performance -- though as I get below 100Hz I am still very much still learning.

I am currently using off-the-shelf active crossovers over various slopes and am happy with 24dB Linkwitz-Riley. Once the drivers have been choosen, the enclosures built, and initial tuning has been done, I will move onto building my own active crossovers.

 

[Todd Shore]

If the Morel 6" drivers are only playing from around 100Hz to 700Hz, then there really shouldn't be a problem with a pair of them coming up short. The way I see it, I am using the best of what that driver has to offer.

How and at what frequency I cross over to a woofer will depend on the characteristics of the drivers and their enclosures. I'm going sealed, at least for everything but the sub -- possibly that too. I don't want reinforcement at the bottom end of a drivers range by exciting resonances, which is what vented achieves -- it floats the driver on a resonant air mass.

If you were trying to create a sealed woofer section capable of 91dB 1W@1M that could cover 30-120 but only needs to cover 40-80, what driver would you select?