[Steve]

I'm working on my bass players bass cabinet and i'm a bit stumped by a
few things. The cabinet is appears to be some homemade contraption
aquired from a pawn shop, so I don't know much about it or how old it
is. It seems to be solidly built though. Inside are 2 cerwin vega 15"
speakers. Model number 153WHF. Before i took the cabinet apart, i
measured the impedance from the jack on the back and i got a reading of
around 8 ohms. Once i had the back off, I saw that the speakers were
wired in parallel with a pretty badly soldered rats-nest old lamp cord
wiring job. I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. This is
strange to me because the speakers are clearly marked 8 Ohms on the
labels stuck to the back of the magnets. Is there an exeption to the
rule of the resistance of a speaker being a little less than the
nominal impedance rating ? What am I supposed to believe ? The meter or
the labels ?

[Richard Crowley]

"Steve" wrote ...
I'm working on my bass players bass cabinet and i'm a bit stumped by a
few things. The cabinet is appears to be some homemade contraption
aquired from a pawn shop, so I don't know much about it or how old it
is. It seems to be solidly built though. Inside are 2 cerwin vega 15"
speakers. Model number 153WHF. Before i took the cabinet apart, i
measured the impedance from the jack on the back and i got a reading of
around 8 ohms. Once i had the back off, I saw that the speakers were
wired in parallel with a pretty badly soldered rats-nest old lamp cord
wiring job. I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. This is
strange to me because the speakers are clearly marked 8 Ohms on the
labels stuck to the back of the magnets. Is there an exeption to the
rule of the resistance of a speaker being a little less than the
nominal impedance rating ? What am I supposed to believe ? The meter or
the labels ?

You didn't tell us HOW you measured the impedance?
Did you simply use a (DC) ohm-meter?

Or did you use an (AC) impedance bridge?
If so at what frequency did you do the test?

[Jens Rodrigo]

Richard Crowley wrote:
"Steve" wrote ...
I'm working on my bass players bass cabinet and i'm a bit stumped by
a
few things. The cabinet is appears to be some homemade contraption
aquired from a pawn shop, so I don't know much about it or how old it
is. It seems to be solidly built though. Inside are 2 cerwin vega 15"
speakers. Model number 153WHF. Before i took the cabinet apart, i
measured the impedance from the jack on the back and i got a reading
of
around 8 ohms. Once i had the back off, I saw that the speakers were
wired in parallel with a pretty badly soldered rats-nest old lamp
cord
wiring job. I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. This is
strange to me because the speakers are clearly marked 8 Ohms on the
labels stuck to the back of the magnets. Is there an exeption to the
rule of the resistance of a speaker being a little less than the
nominal impedance rating ? What am I supposed to believe ? The meter
or
the labels ?

You didn't tell us HOW you measured the impedance?
Did you simply use a (DC) ohm-meter?

Or did you use an (AC) impedance bridge?
If so at what frequency did you do the test?


Richard, that are good questions.

Steve, look at the vaiations of the loudspeaker impedance
vs. frequency:
http://www.cicable.com/grafik/ls35_imp_compo.gif
There is no 8 or 16 ohms. It's changing.
Your DC-Ohm-meter measuring is not more than
a funny guess.

Cheers Jens

[Phil Allison]

"Steve"

I'm working on my bass players bass cabinet and i'm a bit stumped by a
few things. The cabinet is appears to be some homemade contraption
aquired from a pawn shop, so I don't know much about it or how old it
is. It seems to be solidly built though. Inside are 2 cerwin vega 15"
speakers. Model number 153WHF. Before i took the cabinet apart, i
measured the impedance from the jack on the back and i got a reading of
around 8 ohms. Once i had the back off, I saw that the speakers were
wired in parallel with a pretty badly soldered rats-nest old lamp cord
wiring job. I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. This is
strange to me because the speakers are clearly marked 8 Ohms on the
labels stuck to the back of the magnets. Is there an exeption to the
rule of the resistance of a speaker being a little less than the
nominal impedance rating ? What am I supposed to believe ? The meter or
the labels ?


** The two speakers have been reconed at some time.

Once they were 8s, now that are 16s.




.......... Phil

[Phil Allison]

"Jens Rodrigo"

Steve, look at the vaiations of the loudspeaker impedance
vs. frequency:
http://www.cicable.com/grafik/ls35_imp_compo.gif


** Shame that is for a speaker SYSTEM and not a bass driver.

Shame it does not show the DC resistance value, but suggests it may be 6
ohms.


There is no 8 or 16 ohms. It's changing.


** The "nominal impedance" concept takes care of that.


Your DC-Ohm-meter measuring is not more than
a funny guess.


** What ASININE CRAPOLOGY !!!!

No bass DRIVER has a nominal impedance value LESS than the reading given on
a DC ohm meter.

The NOMINAL impedance of a bass driver is normally 10 to 20 % HIGHER than
the DC resistance value, but NEVER less.

So, despite the labelling, the OP has a pair of 16 ohm * nominal impedance*
drivers.





......... Phil

[Vivek]

The graph and illustration was for the OP not for *******s.

"Phil Allison" wrote in message
...
|
| "Jens Rodrigo"
|
| Steve, look at the vaiations of the loudspeaker impedance
| vs. frequency:
| http://www.cicable.com/grafik/ls35_imp_compo.gif
|
|
| ** Shame that is for a speaker SYSTEM and not a bass driver.

[Eeyore]

"François Yves Le Gal" wrote:

On 10 Jul 2006 12:14:21 -0700, "Steve" wrote:

What am I supposed to believe ? The meter or
the labels ?

If you've measured the drivers using a properly working meter and found a 15
ohms DCR, then they have a 15 ohms DCR and are 16 ohms drivers...

CW could have affixed the wrong label, the speakers can have been reconed
using a 16 ohm set, etc.

Phil's idea about reconing sound pretty likely to me esp given the cabinet
they're in ! Tells you something of their likely history.

I have however genuinely come across speakers incorrectly labelled by the
manufacturer though. Years ago ( actually decades ) - some Eminence units.

Graham

[Phil Allison]

"Vivek"




** Go get ****ed you vile, autistic ****.











....... Phil

[Steve]

Thanks for the help guys. I'm going to go with the theory that these
speakers were reconed to 16 ohms at some point. The labels on the
speakers look very old. The Cerwin Vega logo is definetly an older
version with a 1960's-1970's looking font. Too bad they are 16 ohms
though since the amp is only going to put out about half power with the
cabinet running at 8 ohms. On the upside, I did get that nasty wiring
job out of there (lots of terrible and loose solder joints) and I
completely rewired it. Sounds much better now.

[Mike Coatham]

"Eeyore" wrote in
message ...


"François Yves Le Gal" wrote:

On 10 Jul 2006 12:14:21 -0700, "Steve"
wrote:

What am I supposed to believe ? The meter or
the labels ?

If you've measured the drivers using a properly working meter and found
a 15
ohms DCR, then they have a 15 ohms DCR and are 16 ohms drivers...

CW could have affixed the wrong label, the speakers can have been
reconed
using a 16 ohm set, etc.

Phil's idea about reconing sound pretty likely to me esp given the cabinet
they're in ! Tells you something of their likely history.

I have however genuinely come across speakers incorrectly labelled by the
manufacturer though. Years ago ( actually decades ) - some Eminence units.

Graham
The other explanation is that as the OP got a reading of approx 8 ohms at
the conncector, but the individual speakers were approx 15 ohms that they
just might have been wired in parallel??

[Rocky]

jeez.

1. he said the first measurement was at the jacks.
2. he said they were wired in parallel
3. he used the same measurement technique/instrument both times
4. therefore if both speakers are the same when you measure them
individually you'll get double the value at the jacks.
5. If measuring at DC (as is likely) then reconing makes no difference.
You didn't rewind the motor when you put new cones on.
6. If measuring at AC with a small signal (ie not enuff power to move the
cones) reconing still won't make a difference.

rocky



"Phil Allison" wrote in message
...

"Steve"

I'm working on my bass players bass cabinet and i'm a bit stumped by a
few things. The cabinet is appears to be some homemade contraption
aquired from a pawn shop, so I don't know much about it or how old it
is. It seems to be solidly built though. Inside are 2 cerwin vega 15"
speakers. Model number 153WHF. Before i took the cabinet apart, i
measured the impedance from the jack on the back and i got a reading of
around 8 ohms. Once i had the back off, I saw that the speakers were
wired in parallel with a pretty badly soldered rats-nest old lamp cord
wiring job. I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. This is
strange to me because the speakers are clearly marked 8 Ohms on the
labels stuck to the back of the magnets. Is there an exeption to the
rule of the resistance of a speaker being a little less than the
nominal impedance rating ? What am I supposed to believe ? The meter or
the labels ?


** The two speakers have been reconed at some time.

Once they were 8s, now that are 16s.




......... Phil

[Phil Allison]

"Mike Coatham"


The other explanation is that as the OP got a reading of approx 8 ohms at
the conncector, but the individual speakers were approx 15 ohms that they
just might have been wired in parallel??


" I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. "


** Ho hum .....



.......... Phil

[Phil Allison]

"Rocky Rocks in the Head Moron "

1. he said the first measurement was at the jacks.


" I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. "


2. he said they were wired in parallel

" I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. "


3. he used the same measurement technique/instrument both times


" I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. "


4. therefore if both speakers are the same when you measure them
individually you'll get double the value at the jacks.


** Half actually.


5. If measuring at DC (as is likely) then reconing makes no difference.


** Yes it can.


You didn't rewind the motor when you put new cones on.


** Reconing includes the motor - since that is what has become damaged!!


6. If measuring at AC with a small signal (ie not enuff power to move the
cones) reconing still won't make a difference.


** Pure insanity.

Where do all these IDIOTS come from ?




........ Phil

[Rocky]

Apparently this Phil person can't read. I'm truly amazed by his behavior.
Must have had a difficult childhood to need to inflate his importance by
flaming people. Try porn Phil, you'll feel better afterwords.

"i measured the impedance from the jack on the back and i got a reading of
around 8 ohms. Once i had the back off, I saw that the speakers were
wired in parallel "

I concede that I mis-spoke when I stated the impedance at the jacks would be
double, I did mean half.

I also concede that if you do change the motor the DC impedance will change
but this should be quite small if you use the same model motor.

However, if testing with AC, if there is not enough power to move the cone
and voice coil, the AC impedance will depend only on the electrical
parameters. This is basic physics and no amount of audio myth and
vituperation will change it.



"Phil Allison" wrote in message
...

"Rocky Rocks in the Head Moron "

1. he said the first measurement was at the jacks.


" I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. "


2. he said they were wired in parallel

" I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. "


3. he used the same measurement technique/instrument both times


" I cut the wiring and I measured the resistance of the
individual speakers and each was around 14.2 to 15 Ohms. "


4. therefore if both speakers are the same when you measure them
individually you'll get double the value at the jacks.


** Half actually.


5. If measuring at DC (as is likely) then reconing makes no difference.


** Yes it can.


You didn't rewind the motor when you put new cones on.


** Reconing includes the motor - since that is what has become damaged!!


6. If measuring at AC with a small signal (ie not enuff power to move
the cones) reconing still won't make a difference.


** Pure insanity.

Where do all these IDIOTS come from ?




....... Phil

[Phil Allison]

"Rocky Rocks in the Head ****WIT & TOP POSTING Moron "

I concede that I mis-spoke when I stated the impedance at the jacks would
be double, I did mean half.

** Yawn .......


I also concede that if you do change the motor the DC impedance will
change but this should be quite small if you use the same model motor.


** Yawn - begs the question.


However, if testing with AC, if there is not enough power to move the cone
and voice coil,


** ****ing ******** !!

The smallest AC test signal *moves* the whole assembly.

Funny how a speaker ALWAYS makes sound when being tested.

****WIT !!!



the AC impedance will depend only on the electrical parameters.


** Yawn - gotta jam the coil tight in the gap to get that situation.


This is basic physics and no amount of audio myth and
vituperation will change it.


** Shame YOU have not one damn clue about ANY of it -

BLOODY IMBECILE !!





......... Phil