SEAS neo

[AJINFLA]

Well, the new SEAS neo is out, but it's not what I was hoping for :

http://www.seas.no/Prestige%20Diskanter%20PDF/27TAFNCH1397.pdf

Fs 1170 :M . Maybe the pole is vented so I could add a rear chamber..... :roll: . Oh well. The search continues. Maybe Scan will update the 6000 one day.

Cheers,

AJ

[JonMarsh]

Oh, so THAT's what you meant by the Neo.... yeah, they had those there, didn't look all that impressive to me. Guess not to you, either.

[capslock]

It's those 46 mm that bother you, isn't it? In order to life inside a W18 or W22's VC, it needs to be 38 mm.

What really counts is the OD of the motor, the rest can usally be turned. If you loose the centering ridges in the process, you just have to adjust the VC assembly manually and glue it in place.

Maybe Björn can enlighten us about the diameter of the motor?

Other than that:
- highish fs like most of the new Seas designs - do they think that most customers have no use for the rear chamber and lower fs? hopefully all the new models will be supplemented by chambered ones in the future
- nice FR, like all newer Seas Alu domes
- low impedance peak, i.e. heavy ferrofluid (not what I like)
- lots of nominal linear travel
- field in gap of 1.2 T, not really much for a Neo motor
- lowish Le for a driver without shorting rings - I guess they are using a Nd ring sitting on the inside of the VC

[bidland]

It's not the same magnetsystem in the coax tweeter and the regular neo tweeters. The magnet and gap geometry is the same, but the outside diameter is different due to different mounting methods.

The ferrofluid is of the low viscosity type. The impedance peak is lower because the BL is a bit lower than the previous models. The hole in the magnet reduce B a bit, and the v.c. winding width is reduced to 1.1mm to increase Xmax, so here we also reduce the L in BxL. This also leads to lower Le and lower Mms.

Bjorn

[capslock]

Björn (excuse my stubbornly using the ö, but the /o is almost inaccessible through my keyboard, and its the same sound, isn't it),

what is the outside diameter of the new Neo's motor?

what is the B-field in the coax tweeter, more than 1.2 T?

So the coax tweeter of the T18RE does not have a pole piece bore? Why is f_s then around 1100 Hz for both the coax tweeter and the new (regular) tweeters?

By the way, the "new" (different surround) T18RE was just tested in the 2/06 issue of T&T, and its second harmonic is almost 10 dB lower than that of the wide surround, regular ferrite tweeters. Probably due to higher flux in the gap and hence saturation of the iron near the gap...

[bidland]

I can check the exact dimension tomorrow, but I would guess that it's about 40-41mm.

The B-field is the same in the new neo tweeters and the coax tweeter for H1144 and H1333. Both have a hole through the polepiece and the magnet, leading to a chamber that is integrated within the "pot". The magnet is like a coin placed just below the polepiece. This chamber reduce the Fs from 1800Hz in the H625 to 1100Hz in the new models.

I have not seen the test you refer to, but I would guess that the lift in the low frequency range from the "waveguide" effect will have a positive impact on HD measurements. The distortion components does not get the same gain from the waveguide loading.

I hope that magazines and people doing driver comparisons will take a look at Wolfgang Klippel's paper "Measurement and Application of Equivalent Input Distortion" JAES Volume 52 Number 9 pp. 931-947; September 2004

and Steve Temme's "How to Graph Distortion Measurements" Preprint Number: 3602 Convention: 94 (February 1993)

I think that it would be easier to get something useful out of distortion measurements if the fundamental response is normalized. This is easy to do with the TRF module in the Klippel Distortion Analyzer.

Bjørn

[AJINFLA]

It's those 46 mm that bother you, isn't it? In order to life inside a W18 or W22's VC, it needs to be 38 mm.

Yes and no. I still don't know how practical it would be to use the W22 with coincident loading of the tweeter since there would still be surround issues to contend with. That would also force my (dipole) XO upwards and necessitate a 4 or even 5 way. Being less than 38mm would help if that was the approach I took. I'd just like to see a neo tweeter with the low end performance of a H1212. Coaxial mounting to an extended phase plug would then be possible.
The tweeter would simply have to be robust enough to cross in the 1.2-1.4k range (or lower) to make me happy. The SS6000 comes close but is a bit too overdamped sounding. I have an affinity for metal (or other hard material) drivers in case you hadn't noticed .
I'm sort of curious as to why they chose a normal phase shield rather than the hexagrid for this particular driver. If it's good here, then why not on the H1212?

Cheers,

AJ