Saba IV A xover schema needed

      Hallo to everybody,

      I'm Davide from Italy and I'm a new forumer. I'm involved in some diy projects with saba laudspeakers. Most with greencone in openbaffle. Nothing of special or esotheric. Just for fun and passion for old music stuff.

      In these days I have restored a beautiful pair of SABA III and I'm enjoying their sound with a SABA SRI 16.

      Now I have bought a pair of SABA Druckkammer-Hochtöner from a eBay.de to develop a separate box to add to the SABA III. The desired result should be a "SABA III enpowered with a separate SABA IV Druckkammer-Hochtöner". To do this I need the crossover schema of the SABA IV A.

      Somebody can help me?

      Thank you very much in advance and thanks to the forum management too.

      Davide

      Hello Davide,

      please be patient with all the members here, we are not always online, we are only hobby-ists and mostly have only limited time. Some answers can come after days or weeks...

      Let me try to help you, even if i don't own a SABA IV or the manual. Since the crossovers in the old Saba speakers are mostly simple designed, it will not be very complicated to add the horn tweeter.
      In similar speakers (i.e. Isophon) you can find a crossover network, that doesn't limit the normal tweeter and only has a high-pass for the horn tweeter.
      You can easily calculate the crossover if you have the impedance of the tweeter. I suggest you use a high-pass of third order, in order to limit the power going to the horn. A high pass of second order (12dB/oct.) will do too, but the voice-coil of the tweeters are quite delicate, and spare-parts are not easy available.
      So if you don't limit the normal built-in tweeter, i think a crossover-frequency of about 6 kHz will be best, so you only use the tweeter as a super-tweeter.

      Perhaps you try the real easy to use tool from Strassacker:

      http://www.lautsprechershop.de/index_tools_en.htm

      I think the page is available in italian too....

      Take the 18 db (Butterworth) crossover, type in the speaker impedance, the crossover-frequency (here: 6.000 Hz) and at last the sound pressure levels of low and high speakers. (For low take the given 90 dB, and for the tweeter take 96 (or 98) dB, it has a lot higher output than the rest of the box!) Then click on "berechnen" and that's it!
      You only have to take the parts for the high pass (2 capacitors, 1 coil and 2 resistors) and build up your network. The rest of the crossover in the box can be left unchanged.

      So try this way, and if the sound seems too bright, calculate for new resistors.
      As i built a lot of speakers (and so networks too) i have always a lot of parts to try out other values. You have to find the setting that sounds best for you and that relates to the room where you listen with the box too. There will be no patent that works for everyone!

      Greetings from bavaria!
      Gruß, Gunnar

      Hello Gunnar,

      first of all, thank you very much for yours attention and interesting suggestion. I will follow your method to make my own network for this tweeter. Very useful the suggestion to choose a third order network and only for the high-pass filter. I argue that the low-pass is built-in in the electro-mechanical characteristis of the tweeter (better a mid-tweeter) because I read on the old product brochure that it is limited to 14.000 Hz.

      There will be a little bit of funny work!

      Thanks a lot and greetings from Italy!

      Davide

      Hello and Happy new year to every forumer.

      I wish show you the result of the work around the SABA III that I done with yours help.

      The work consists of an external SABA Druckkammer-Hochtöner (taken from SABA IV) put on top of the SABA III box and filtered with a stand-alone thirth-order filter. The added tweeter is in parallel with the entire SABA III input plug.

      The sonic results are very interesting. The external tweeter gives more spatial image to the sound (horizontal and vertical enlargement of the sound image) and refine the high frequencies. Morover the external chassis can be rotated respect to the SABA III baffle, to fine-tune the Druckkammer-Hochtöner level in respect to those of the internal tweeter without electrical attenuation filtering.

      Here some images:

      http://img585.imageshack.us/img585/8674/exc1.jpg
      http://img18.imageshack.us/img18/6939/4qod.jpg
      http://img594.imageshack.us/img594/4273/q910.jpg
      http://img809.imageshack.us/img809/3496/2bii.jpg
      http://img69.imageshack.us/img69/3018/mzk1.jpg

      Thanks a lot and regards

      Davide

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