Adaptor Plate for SB Acoustics SB26ADC/SB26CDC, WG300 combination

Hi Forum

I think it is safe to say that SB Acoustics SB26ADC and SB26CDC are still some of the best bang for the buck tweeters. Sure you can get better, but for a price around 55 Euro, it is really hard to beat.
One thing I like in particular is the Xmax of 1.2 mm peak-peak.
You don't find that in many dome tweeters. What that means is the ability to cross over rather low.
Combining this with a waveguide just adds to this, and you would be able to cross over around 1.2 - 1.5 kHz and still have pretty good output.
One of the best bang for the buck waveguides is or sure the Monacor WG300, at 20 Euro again it hard to beat.
What is more the geometry promise a really good on axis and off- axis reponse.

A vey goo example is Heissmann's implementation:

The waveguide is made for the Monacor DT-300 tweeter, which is of course not a contender for the SB tweeter, and the challenge her is that it does not really fit the SB tweeter right away, ad an adapto plate is needed.
Heissmann has made a plate for the Scan-Speak Discovery D2604/833000

I see that xrk971 has also made an adaptor plate for another good band for the buck tweeter Dayton RS-28

Question is now if someone has made an adaptor for the SB26ADC?

I think it would be important to include the phase plug in the design

Have been fiddling a bit with FreeCAD, but must say I do not master it yet to do this myself from scratch. Maybe with some help or a good starting point ....

Plan would be to use something like JLCPCB to do the printing, and only printing the adaptor plate will of course keep the price down.

By the way this is the tweeter used in Revel F206 with a 5" waveguide

I know also the good Augerpro has made some excellent waveguides, but I would prefer a round guide over an eliptic not least to make the routing for it, and again I think the WG300 has a really good geometry and freq response.
Measurement of SB26ADV + WG300 in the attachment, measured in baffle, width 220, height 400, chamfering 20mm.


  • SB26ADC WG300.png
    SB26ADC WG300.png
    106.3 KB · Views: 109
  • Like
Reactions: 1 user
Just so we are all on the same page, what would be the typical cost to have a pair of 6.5 inch waveguides printed?
Depends on the material.
Have tried right now to upload the 6.5x1.2 rA SB26 v2.step file from "6.5" waveguide (circular mouth)" on Soma Sonus, and the price for one piece is:

9000R Resin: 30.14 USD (only stable up to 46 degree C)
8228 Resin: 43.06 USD (stable to 56 deg C)
FDM ABS: 111.94 USD (good material for permanent parts)
321PA-F Nylon: 103.33 USD (heat proof to 147 deg C, really good)

If you choose some of the cheaper materials you risk damages in direct sunlight, so I think not really good for a permanent part.
And more than 100 usd for one piece, I think is pretty expensive. All needs transport on top and VAT.

You can probably find cheaper alternatives, but probably not by much, but would of course be happy for better information on that point (I'm new to printed parts ;) )
Last edited:
Thanks Pida, nice! Do you not have to remove the front panel of the tweeter to fix the WG300?
There was no need to remove the faceplate. I used 3mm MDF ring, and trimmed the rest of the lip to fit properly to the faceplate.
4 countersung flat head screws to attach ring to the WG, and drill 4 holes to attach faceplate to mdf ring.
After it is all ready, it is goog to fill the space below the ring with the resin or silicon glue.


  • SB26ADC WG300 fit.png
    SB26ADC WG300 fit.png
    17.9 KB · Views: 64
Last edited:
The Visaton WG148 is easy to get. I wish someone made an adapter for that one to most flat flanged Seas and Morel domes.
Not sure about the Morels (check the hole pattern and bolt circle diameter), but the WG148 mounts perfectly to the flat-flanged Seas tweeters if you just enlarge the screw holes in the Seas flange by 0.5-1.0 mm. If you do it carefully on a drill press it's such a small modification that you basically can't really see it afterwards.
I did figure out most Seas tweeters will fit with slight modification of the screw holes. The chamfer around the dome inner flange is always an issue and causes FR problems in the WG. The WG300 has a lip which fills the step created by the inner lip, so it fits with more domes. I wish they did that with the WG148.