8 ohm fane sb1000 measuring at 4 ohms!

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   I am refurbishing my old 218's that are loaded with fane sb1000. When I had the cabs made I was told they were loaded with new 8ohm fane sb1000 x2 per cab. Each cab is supposed to be 4ohms (2x 8ohm in parallel) When I stripped them out to paint I noticed the wiring appears to be in series. The drivers still have the original stickers and all say 8 ohms but when I measured them with my meter they all read exactly 4ohms! Now I realise that impedance and static resistance isnt the same and they probably read lower than 8ohms but seriously 4ohms?? Anyone else found this? I dont know what to do. I dont want an 8ohm load as they will be underpowered but if I wire in parallel then it will be 2ohms! Any insights? I am thinking all 4 must be mislabelled but seems unlikely?

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
Natedub Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 07 January 2013 Status: Offline Points: 126	Post Options Post Reply Quote Natedub Report Post Thanks(0) Quote Reply Topic: 8 ohm fane sb1000 measuring at 4 ohms! Posted: 01 March 2018 at 6:46pm
	I am refurbishing my old 218's that are loaded with fane sb1000. When I had the cabs made I was told they were loaded with new 8ohm fane sb1000 x2 per cab. Each cab is supposed to be 4ohms (2x 8ohm in parallel) When I stripped them out to paint I noticed the wiring appears to be in series. The drivers still have the original stickers and all say 8 ohms but when I measured them with my meter they all read exactly 4ohms! Now I realise that impedance and static resistance isnt the same and they probably read lower than 8ohms but seriously 4ohms?? Anyone else found this? I dont know what to do. I dont want an 8ohm load as they will be underpowered but if I wire in parallel then it will be 2ohms! Any insights? I am thinking all 4 must be mislabelled but seems unlikely?

RoadRunnersDust Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 03 December 2013 Location: United Kingdom Status: Offline Points: 561	Post Options Post Reply Quote RoadRunnersDust Report Post Thanks(0) Quote Reply Posted: 01 March 2018 at 8:55pm
	anywhere between 4-6 Ohms DC Resistance is very believable for an 8R driver :) Only way to really be sure is to run a sinewave sweep and get an impedance plot done (I think REW has this functionality? if not theres a few of the PHAT CAR CHOONZ brigade using similar software to measure T/S parameters, Impednace, etc.)
	www.guildfordcablecompany.co.uk

Natedub Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 07 January 2013 Status: Offline Points: 126	Post Options Post Reply Quote Natedub Report Post Thanks(0) Quote Reply Posted: 01 March 2018 at 10:14pm
	Thanks for your reply, that puts my mind at rest. I have seen 5-6 ohms on 8ohm driver but never as low as 4ohm before. Learning all the time

RoadRunnersDust Members Profile Send Private Message Find Members Posts Add to Buddy List Young Croc Joined: 03 December 2013 Location: United Kingdom Status: Offline Points: 561	Post Options Post Reply Quote RoadRunnersDust Report Post Thanks(0) Quote Reply Posted: 02 March 2018 at 5:13am
	They're all "Nominal" ratings... look at the rated impedance plot for most drivers. They just have to stick the label for the nearest standard of speaker impedance on it for marketing
	www.guildfordcablecompany.co.uk