Does 5.3ohms DC signify a 8 ohm drive unit ?

[buganna]

Ok so I'm new to all this , but learning

I have a 3 way speaker , that I need to work out a Xover for it

The midrange is a 5.25" dynaudio driver

I measured 5.3ohms DC resistance ( both measured identically )

Does this mean the drive unit has a 8ohm impedance?

Or maybe 6ohm ?

No idea if dynaudio make 6ohm drivers ...but a reading of 5.3ohms DC seems low for a 8ohm driver ?

Any info greatly appreciated

 

[rayma]

Yes, it is likely rated as 8 ohms. This is only a nominal rating, since the actual driver impedance
will vary considerably over its range, and will always be higher than the DC resistance.
Look at some data sheets and see.

 

[buganna]

Thanks ... I looked online ( utube ) and a video showing drive unit DC resistance,. Showed a 7.2ohms reading

The guy stated that this is typical for a 8ohm drive unit

So my 5.3ohm seem a bit low ?

 

[Rev. Billy Bob]

It's probably a nominal 8 ohm driver, but impedance varies with frequency.

To design a crossover, you really need to know the impedance of your driver at the desired crossover frequency.

Designing a three way crossover is not a trivial matter; it's well past my level of expertise.

If you post the drivers you plan on using, someone more knowledgeable will probably be able to help you.

 

[Lojzek]

Dynaudio classifies their drive units with Re=5 ohm as being 8 ohm nominally. Check their datasheet.

 

[buganna]

Unfortunately there are no markings on the midrange or bass woofer drivers

The speakers are SD Acoustics ' OBS '

I purchased them + some previous owner had replaced the Xover with just a single cap for tweeter ...and single cap for mid .. nothing on woofer

Sounded very boomy + bass heavy

So I found a Xover schematic for the SD1 model ... Similar speakers I guess , but with a 8" woofer instead of my 6.5" woofer

I made up a Xover using that schematic, and it transformed my speakers ...bass now much deeper , tighter , boom had gone

But midrange sounds a bit hollow / weak

So I'm wanting to calculate the impedance of my mid driver ... As possibly different to the SD1 mid.driver

Ps;. I've ordered a Behringer Deq2496 , EQ / Room corrector ... As I know I can't get the Xover perfect myself ... hopefully the Behringer will flatten the frequency response..... ( Never used one before, but thinking about it ,. It could be highly useful for ALL systems )

 

[buganna]

Dynaudio classifies their drive units with Re=5 ohm as being 8 ohm nominally. Check their datasheet.

That's great ...thanks ... very helpful

This means my bandpass filter is incorrect....so need to modify it for a 8ohm driver .....

 

[Rev. Billy Bob]

Does this look like your driver? The data sheet for the 8 ohm version says 4.9 ohm dcr.

Dynaudio Esotec 15W75-08 Woofer | Hifi Collective

 

[Lojzek]

If you provide details of the rest of the system you are trying to design, more people could give you guidance. Search forum for simulations tools and read the sticky threads.

 

[buganna]

The front of the driver looks the same ......but the rear is different.... These drivers are from 1990s....but still function and no visible detoriation...

The speakers consist of a Monacor ribbon tweeter + 5.25 dynaudio mid + 8" Audax ( doped paper ) ... All pretty old ..the audax had to be refoamed

See photos ...

 

[buganna]

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