Big square magnet speakers

[Hydrolastic]

Hello Trying to learn a bit about speaker impeadance and clarify something I saw on Frankengrand. The old big amps were Biamped and used the three wire setup. Frankengrand used the big square magnet speakers I think from the later astrosonic. How do you match speakers in this setup. Is the impeadance the same as the horns ? Or the same as old speakers that they replaced. Thank you. Hydro

[TC Chris]

Speaker impedance isn't crucial. Mis-matching may affect tonal balance a tiny bit in critical listening, but only if you compare the sound to another ore accurate source. And besides, I'm betting that big Maggie speakers are likely all 3.2 ohm. Just a guess; you guys with schematics can correct me.

Chris Campbell

[electra225]

Hydro, check your schematic for your 1960 CG for speaker impedence. The original 15' woofers in a Concert Grand are 8 ohm, one with a 50-ounce magnet, one with a 35-ounce magnet. The horns are 4"X10". I'm not sure about the impedence on those. Again, the schematic may list the horn impedence. If not on the schematic, refer to the parts list. It may tell you. You can also measure the resistance on the horns. It may not be exact, but you can figure it out from there. The speakers you posted are 137 EIA code, Chicago Telephone Supply, dated 1968, so they are probably from an Astro Sonic model. They should work, but they are not close to being the right ones. I hope this answers your question.