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15 Inch JBL

PostPosted: Wed May 21, 2014 6:04 pm
by GaryL
I have a reconed 15 inch JBL that is registering about 25 ohms on a meter. I wonder if I should try it on an amp that is looking for 8 ohms? My amp repair man got the same reading I did on the speaker. Any comments would be appreciated.
GaryL

Re: 15 Inch JBL

PostPosted: Wed May 21, 2014 10:17 pm
by alexjones
Gary,
That seems rather strange. An 8 ohm impedance speaker should have a DC resistance of around 6 ohms. I would double check your measurement. Unless you put a 32 ohm impedance speaker in there. What recone kit did you use? I am assuming the speaker is a D130 right? When you making measurements, make sure it is DC resistance and your battery in your ohmmeter is good.
Alex

Re: 15 Inch JBL

PostPosted: Mon May 26, 2014 12:56 pm
by tewhite
Weird - I`d sure check something .. The most I`ve heard of was 16 ohms and it was usually still around
8 ohms !

.Terry

Re: 15 Inch JBL

PostPosted: Tue May 27, 2014 5:55 pm
by GaryL
Alex and Terry,
Thanks for your posts. I did not recone this speaker and purchased it already reconed. It says 16 ohms on the speaker itself. I remember 1 measurement said around 12.3 ohms. Anyway, I'll give it another try testing with new battery.
GaryL

Re: 15 Inch JBL

PostPosted: Tue May 27, 2014 7:36 pm
by alexjones
Gary,
12.3 ohms would make sense for a 16 ohm speaker.
Alex

Re: 15 Inch JBL

PostPosted: Mon Jun 09, 2014 12:14 pm
by senojnad
12.3 sounds right for a 16 ohm speaker.
Just to add to the confusion -- many of the JBL D130's were marked as 16 ohms but were actually 8 ohms. Danny McKinney (Standel) told me that MOST of those marked as 16 were actually 8. The D130 in my Standel is marked as 16, but actually measures between 6 and 7, making it an 8 ohm speaker..

Re: 15 Inch JBL

PostPosted: Tue Jun 10, 2014 6:25 am
by GaryL
My JBL is OEM marked D130F 16 ohm and was re-measured and verified as 6.8 ohms. I've been using it for several weeks with my Fender Super Champ XD head and the combination sounds great.
Thanks,
GaryL

Re: 15 Inch JBL

PostPosted: Tue Jun 10, 2014 5:38 pm
by chanavin
Hi Guys,
Not sure how you are measuring impedance of your speakers? But if you are using a
mulitimeter, most multimeters measure resistance, not impedance.. Resistance is a, DC, 0hz frequency, measurement.
Impedance is measurement at a certain frequency, say 1 khz.. The impedance will always be higher than
the dc resistance, on speakers, as its a sum of dc resistance and AC reactance..
so its common for JBL 16 ohm (impedance) speaker to measure lower resistance
on multimeter, i think mine is about 9 ohms

I think older speakers like the JBL's were marked using Impedance, but seems like a lot of modern speakers
these day,s are using DC resistance...


Hope this doesn't muddy things up :D

Chuck H...