[Speedskater]

If all the drivers are from VMPS loudspeakers, then the only similarity between them is 'they all look like woofers'. They can easily have different magnets, cone construction, voice coils and impedance.

[opnly bafld]

I think what is confusing us is that we are assuming drivers are 4 ohm or 8 ohm.     If the speaker maker uses custom drivers , say 2 or 3 ohms  OR say 16 ohms...then they can series or parallel as desired.

That was the point of my post about Focal and others that use an odd number of drivers (maybe I wasn't clear enough).

[Housteau]

I think what is confusing us is that we are assuming drivers are 4 ohm or 8 ohm.     If the speaker maker uses custom drivers , say 2 or 3 ohms  OR say 16 ohms...then they can series or parallel as desired.

No.  That was my mistake at the beginning, but if you look at my other post, I state that the drivers are 6.3 ohms each.  I have two spares.

[mrhyfy]

No.  That was my mistake at the beginning, but if you look at my other post, I state that the drivers are 6.3 ohms each.  I have two spares.

6.3 ohms is too close to 8 ohms to do the trick in this situation

[FullRangeMan]

So three 6.3ohms woofers are 18.9ohms in serial or 2.1ohms in parallel, dont see a good result for audio speaker, unless for vintage 16ohms tube amps.

[opnly bafld]

Most (all?) drivers have a lower dc resistance than their rated nominal impedance.

I just checked one a Satori MW19P-8
Nominal rating 8 ohms
DC 6 ohms

4 ohm version of the same driver has a DC resistance of 3.4 ohms.

[FullRangeMan]

Maybe the 6.3ohms be the VC DC resistance not the driver nominal rated value, which could be 8 ohms.

[Speedskater]

That was the point of my post about Focal and others that use an odd number of drivers (maybe I wasn't clear enough).

Focal has resources, not available to the typical audiophile, like having drivers manufactured with what ever impedance they wish.
Brian Cheney at VMPS had skills that very few audiophiles have.

The point is, there is no good way to wire three identical 4 or 8 Ohm drivers. This best is three 4 Ohm drivers in series for a 12 Ohm load.

[opnly bafld]

Probably be good if you stopped speed skating long enough to follow all the posts made. 

[planet10]

What do you could suggest to the OP calc the resistance value to 3 woofers to linearize the impedance?

Woofers with low VC inductance. Or active.

Typically one uses a zobel if you can’t do that.

dave

[Speedskater]

Probably be good if you stopped speed skating long enough to follow all the posts made. 

Not speedskating, they closed all the rinks several weeks ago. Now the paths in the parks are also closed.
That was a direct response to your reply #21.

[ZAKski288]

Hello Dave , this is how they are wired

Here is the driver information
 



Good luck Ken

[FullRangeMan]

Thanks for posting Ken.
This 3 driver connection are a mix of Parallel and Serie or a quasi Parallel.
The final impedance resulting should be measured.

[Housteau]

Thank you Ken.  This is what I had thought was most likely and had posted in this thread, two in series and in parallel to the third.  But, the discussions against it were logical and compelling.

[planet10]

Ken,

I used the same scheme but w 3x Delco 6x9 (the good ones) — a bipole with 2 sorta side firefiring drivers providin ght rear output. The 2 back drivers in series have the same output as the driver in parallel to the series pair so the same total output as a pair.

dave

[FullRangeMan]

This is what we have here with this 3 drivers:

[planet10]

This might be clearer:



dave

[FullRangeMan]

I dont see any gain in SPL with this schema, do you have measured gain Dave?

[ZAKski288]

So now the real question. Each bass module has three speakers , adding a second bass module, what will need to be done to the passive crossover? Crossover is a 2.8 mH coil for the single bass module. Each bass module measures 4.1 ohms at the binding post.
       
        1. So you would wire them in Series or Parallel ?

        2. What would need to be done to passive crossover ?

    Picture for visual effect


          Thanks Ken

[Housteau]

The passive crossover is not an issue, because most have converted over to an external digital one very early on.  I would certainly go in series for an 8 ohm load.   My understanding is that those very few with the double stack were told the same.