Hi Paul:
I have only ever used the smaller 11mm x 15mm speakers and as far as I'm concerned they sound great. In most cases I am able to fit in two of them:
http://www.digikey.com/product-search/en?keywords=423-1203%20ND
There is no indication that they are to be discontinued, and they are about half the price of the grand speakers.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
I've been using Knowles brand "Grand" 13x18mm sugarcubes mainly in my recent HO conversions to DCC. I got a note from DigiKey today that advises these will go out of production this year. Before deciding to (and how much) to stock up, I sent a note to Knowles inquiring whether a similar replacement will be offerred. I prefer the Grand to the smaller Donau model unless I have space limitations.
The DigiKey note leads to a potential substitute they have. Both are the same size and 8 ohms. The substitute is more expensive. DigiKey has over 6000 of the Grand in stock so I doubt they will become unavailable immediately.
http://www.digikey.com/classic/ObsoletePart.aspx?dkcid=3163&WT.z_email=obsolete&pn=423-1200-ND
Please advise if there are other speakers you have used in this size range. I'd like to consider alternatives.
Paul
Modeling HO with a transition era UP bent