SB26ADC, SB17NACS and ???

Hejlskov

Member
2019-11-23 8:49 pm
Hi :)
I am new at this site, and I must start by saying there is a lot of excellent, usefull information around.

I would love to make a speaker that could play deep og precise bas without the need of a separate subwoofer. A speaker that could play every detail dynamicly and well balanced. I prefer music over movies.

I am planning to to put some SB Acoustics drivers together.
A SB26ADC, a SB17NACS35-4 and two SB23MFCL45-8 in parallel.
Crosspoints at around 350Hz and 2kHz.
Using XSim I can get a pretty nice result, but I could really need some advise.
Will this work in real life?
Does it make sense to use two subwoofers, or will it basicly bring my amplifer to it knees?
Will the SB23MFCL "play music" up to 350Hz or I be better of using two SB23NBACS45-8, which should be in a larger box than I am going for?

How about the crossover? Where can I improve, what to look for? Is it important to have a steep curve when I invert the mid? In that case I have failed :)

The box would be around 80L, vented for the subs/bas (fb could be tuned as low as 26Hz)/and 10L sealed for the midwoofer

Yes I know I will have to look at baffle difraction, but i am a newbe and got to start somewhere :)

Any comment and advice is really appreciated, and I am eager to learn.

Thank You.
 

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I would love to make a speaker that could play deep precise bass without the need of a separate subwoofer. A speaker that could play every detail dynamicly and well balanced. I prefer music over movies.
or.... be better of using two SB23NBACS45-8, which should be in a larger box than I am going for?

An amplifier which can drive two SB23NACS45-8 woofers in parallel, and a cabinet with a ported 110 liter (3.6cuft) woofer volume would meet your bass requirements. Have you sketched a few cabinet shapes with this volume?

Sony AR1 for front woofers.
Kronos inspired for side-side woofers.
 

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Properly executed, a sealed woofer will have superior transients and phase (square wave reproduction) when compared to a typical ported woofer.

To keep up with your sealed volume 6.5" SB17NAC35-8 midrange you need a big 110 liter box for a 12" sealed woofer, but side woofer mounting is becoming common to keep a narrow front baffle. There are a few 12" woofers like the SB_Acoustics SB34NRX75-6 which produce deep ~37Hz bass in a tight transient SEALED 3.5cuft cabinet.

Adding stuffing to a sealed woofer box increases the effective volume by 15-20%. For the SB34NRX75-6, a 3.5cuft + firberglass stuffing(safe sealed box) moves the Qtc slightly below 0.7 with -F3 = 37Hz.

Zilch praised the bass from the SB34NRX75-6 in his SB12.3 design (MTM + W) kit.
 

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I've used the SB26ADC and SB17NAC (8 ohm) and both are great drivers. I'd be inclined to go with the SB23NAC (NBAC) over the SB23MFCL to keep it in the metal family as well as I had some issues with driving the 4 ohm version of the SB23MFCL. In addition it's a subwoofer and not a woofer so crossing over higher may be a problem.
 

Hejlskov

Member
2019-11-23 8:49 pm
Thank you for the replies.
I have only a sketch of the cabinets in my head.
I have previous made a speaker of two spheres, and planning on a similar setup for SB26ADC and SB17NAC, but I would immerse the tweeter into the larger sphere. This sholud be on top of the bas cabinet...inspirred by B&W.

Any thoughts about the crossover?

Thanks :)
 

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Using spheres for your tweeter and midrange is not "volume efficient". I suspect for about the same total height, you could design a bass cabinet close to 100 liters by sharing a rectangular top with the T-M. To reduce diffraction you could bevel or quarter-round the top baffle edges.

Commercial speakers which use spheres typically include large woofer cabinets to produce bass which supports the large sphere investment.
 

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dwk123

Member
2002-02-06 4:51 pm
I don't have any personal experience, but Rick at Selah Audio has 2 models that use dual SB23MFCL woofers - the Coesivo uses a Morel Rohacell mid, and the other unnamed SB 3-way uses the MR13P and 29BAC beryllium tweeter. I"m not sure where he's crossing, but if a 3-way with the MR13P is workable, I have to imagine that the SB17 shouldn't be a problem.