Monitor 5b impedance question

[k0syak]

Hi!
I've recently become a (proud :)) owner of a pair of Monitor 5b's (SL2000 tweeters version). I've seen their impedance listed in different places either as 8ohm or 4ohm.
Does anyone know what the real impedance is? Measurements would be more than welcome :)

[jakelm]

http://polksda.com/pdfs/MonitorReferenceManual.pdf

[k0syak]

http://polksda.com/pdfs/MonitorReferenceManual.pdf

Thanks!
Does this one (taken from the site) relate to the later model?
============
Overall Frequency Response 30Hz - 25kHz
Lower -3dB Limit 43Hz
Upper -3dB Limit 23kHz
Nominal Impedance 8 ohms
Recommended Amplifier Power 20-125 w/channel
Efficiency 90 dB
=========================

[engtaz]

polksda.com site has a lot of info on older Polks.

[jakelm]

Thanks!
Does this one (taken from the site) relate to the later model?
============
Overall Frequency Response 30Hz - 25kHz
Lower -3dB Limit 43Hz
Upper -3dB Limit 23kHz
Nominal Impedance 8 ohms
Recommended Amplifier Power 20-125 w/channel
Efficiency 90 dB
=========================

You said 5b's right? With sl2000 tweeter? Then thats it.....

[k0syak]

You said 5b's right? With sl2000 tweeter? Then thats it.....

I'm totally confused now :)
What I've quoted is from this page http://www.polkaudio.com/homeaudio/specs/monitor5/
It seems to be about the newer (SL2500) version,no?

[heiney9]

I'm totally confused now :)
What I've quoted is from this page http://www.polkaudio.com/homeaudio/specs/monitor5/
It seems to be about the newer (SL2500) version,no?

Yes, that is correct the Monitor's on the Polk Audio site are Series II and they have the newer sl2500 tweeter.

As Engtaz suggested go to www.polksda.com as he has scans of original owners manuals and literature for the original series of monitors, etc.

H9

From memory the early model 5's were 4 ohm nominal and the later model 5's (not Series II) were 6 ohm nominal.

Why do you ask? Any series monitor 5 is very easy to drive and presents no problem for any receiver.

[NeilGabriel]

From 1988 manual.

I've run my 5Bs with several different amps/receivers and never had any problem.

[k0syak]

From memory the early model 5's were 4 ohm nominal and the later model 5's (not Series II) were 6 ohm nominal.

Why do you ask? Any series monitor 5 is very easy to drive and presents no problem for any receiver.

I was just wondering why all the different specs and which model exactly do I have. It says 5 92597 on the back, is it possible to figure something out of this? And yes, they don't make it hard on the amp :)

[Ron Temple]

Pull out the tweeter or a the driver...there should be a date stamp on it...might be build date or when it entered inventory, but it will close to when the speaker was originally manufactured.

[k0syak]

Pull out the tweeter or a the driver...there should be a date stamp on it...might be build date or when it entered inventory, but it will close to when the speaker was originally manufactured.

Thanks, gotta try it.
Also, does anyone know if they are magnetically shielded? (i.e. is it safe to place them very close to the computer and the display?)

[NeilGabriel]

They are not magnetically shielded. This is vintage (pronounced, vin-taaahj).
The cabinets are quite dense, but I had a pair of 10Bs near my rear projection LCD and definitely got some interference on the edges. I was worried about pulling a mid out, but they come out easily, though you need to be careful not to let it slip and snap a connection as they are heavy.