Seas W18E001 changed technical datas

hubert · « **on:** 30 Jun 2005, 09:48 pm »

Hello Dave,

Are you aware that this driver has completely changed since june?
Another magnet motor, even different suspension and on!!!

http://www.seas.no/PDF%20data%20excel%2005/W18E001E0018.pdf

Regards,

David Ellis · « **Reply #1 on:** 1 Jul 2005, 12:39 pm »

Interesting,

I am glad that I have about 80 of the old version remaining.

The changes don't look dramatic, but may require a change in crossover. I really don't know at this point.

I do notice the inductance of the new driver is considerably higher, and the cone looks slightly heavier. The heavier "cone" might be due to a heavier surround. Indeed the shape of the response curve looks different in the 2500hz zone. This is directly due to the surround material. Indeed there has been some "flux" in the surround material over the years, but this change seems dramatic too.

I will certainly query SEAS concerning the changes. Thanks for letting me know about this.

Dave

David Ellis · « **Reply #2 on:** 1 Jul 2005, 02:18 pm »

I queried John Stone this morning regarding this issue. He responded thus:

Quote

Dave:
There are no changes to the W18E001. If you are referring to the data sheet on the web site, we have redone the data sheets using far more accurate measurements than in the past. We now use the Klippel measuring system as a key element in determining the TS parameters. But the actual drivers are unchanged.
John

brj · « **Reply #3 on:** 1 Jul 2005, 04:48 pm »

Hmmm... so what do you do with this information? Since the new curves for the current driver looked different enough to prompt comments about crossover adjustments, do you still still react to the adjustments even though you now know the driver to be the same? I don't know anything about the various measurement systems, but I guess I'm intrigued because I never considered how measurement methodology could impact a speaker design. (Subjective hearing vs. objective measurement argument aside.)

Jason1 · « **Reply #4 on:** 1 Jul 2005, 06:09 pm »

The person designing a crossover measures all of the drivers T/S parameters, and frequency response before doing anything. A manufacturer's listed specs play no role in crossover design.

hubert · « **Reply #5 on:** 1 Jul 2005, 06:27 pm »

Hello Dave,

<< John Stone responsed: there are no changes to the W18E001...

-Drawing seems to show a shielded magnet.
-Using a box calculator:
with the older datas: 22liters QB3 (that's the 1801)
with the new datas: 34liters QB3 (is it still a 1801?)

All this matter makes me laugh, fortunately the 1801b rings well using the older datas.

David Ellis · « **Reply #6 on:** 1 Jul 2005, 10:30 pm »

It the realm of ported cabinets, I have learned over time that tuning by ear IS the only way to accomplish the proper bass response from a ported bass system.

I am not sure what the bigger manget thingy is.? It might be simply a rubber boot around the magnet for shipping protection. I don't think it's shielding.

Dave