Seas Idunn

[Jonasz]

There's a new Seas twoway using U18RNX/P and the DXT tweeter available. Off axis respons looks awesome just like Mark K's new design.

http://www.mamut.net/dynabel/idunn_.pdf

[Mark K]

I think that provides an interesting contrast to my design. The off axis curves are similar above 3k, due to the DXT tweeter, but the higher xover point and the higher order crossover lead to the typical off axis dip at 1-2k and relative peaking 2-3k in the power response.

The ER18DXT's lower order crossover and lower cross point even this out much better if you look at my curves in the 1-3k range compared with the Seas' design. This is right in the range of the higher female voices, lot's of brass/wind

[Jonasz]

I think you're right about that. I wonder how the new woofer compares to the ER18? Seems it has the same motor with the copper ring.

[Jed]

I think you're right about that. I wonder how the new woofer compares to the ER18? Seems it has the same motor with the copper ring.

I don't think it has copper in the motor... IIRC after viewing Zaph's test of it.

[Jonasz]

I don't think it has copper in the motor... IIRC after viewing Zaph's test of it.

This woofer is brand new and I don't think Zaph has tested it yet (but he tested the U16 IIRC). Here's a link to the pdf: http://www.seas.no/images/stories/pr..._datasheet.pdf

[JonMarsh]

Suspicious looking impedance bobble at 800 Hz...

Is that a real phase plug or a cosmetic dust cap?

It would be untoward and not diplomatic to pan the Seas design out of hand without having heard it, BUT, sheesh, folks, a 2.2 kHz crossover? Do you really like listening to the midwoofer's energy storage that much? I don't like taking them up to 1700 or 1800 even anymore...

Yeah, I'm just being a curmudgeon. ThomasW may be a curmudgeon in training... who do you think is training him? :W

It'll be a dark day before you pry the ER18RNX's out of my cold dead hands....

[Mark K]

I agree with Jon,
I think these are very similar in motor structure if you go to the www.seas.no site and review the pdf's. The U series looks cooler and looks like it can get by with a more simplistic xover, so manufacturers might like it.

The ER18, unfortunately "looks" like your grandma's speaker. Completely nondescript. A real bluehair...

Still, the ER18 appears to be the better driver. Or at least that's my WAG not having tested the U version...

[Jonasz]

Suspicious looking impedance bobble at 800 Hz...

Is that a real phase plug or a cosmetic dust cap?

It would be untoward and not diplomatic to pan the Seas design out of hand without having heard it, BUT, sheesh, folks, a 2.2 kHz crossover? Do you really like listening to the midwoofer's energy storage that much? I don't like taking them up to 1700 or 1800 even anymore...

Yeah, I'm just being a curmudgeon. ThomasW may be a curmudgeon in training... who do you think is training him? :W

It'll be a dark day before you pry the ER18RNX's out of my cold dead hands....

Have Seas ever made a fake phaseplug? This is what the pdf says:

Bullet shaped phase plug reduces compression due to temperature variations in the voice coil, avoids resonance problems which would occur in the volume between the dust cap and the pole piece and increases the long term power handling capacity.

The impedance irregularities are also found in more or less every Scan-Speak midwoofer and in my world they are still pretty darn good (though a little spendy).

[Jonasz]

I agree with Jon,
I think these are very similar in motor structure if you go to the www.seas.no site and review the pdf's. The U series looks cooler and looks like it can get by with a more simplistic xover, so manufacturers might like it.

The ER18, unfortunately "looks" like your grandma's speaker. Completely nondescript. A real bluehair...

Still, the ER18 appears to be the better driver. Or at least that's my WAG not having tested the U version...

Am I the only one that like tho looks of the ER18?

[JonMarsh]

Am I the only one that like tho looks of the ER18?

I do, too- partly because it's clean and non-descript- which I don't view as liabilities. I've also found through a variety of near field testing that most phase plug equipped drivers have some predictable behaviors as you get closer to breakup modes, ones I don't like. The 800 Hz bobble COULD be a surround resonance, but that would imply that PE has figured out how to make drivers without that (RS180) whereas Seas hasn't....

Since I don't use the ER18RNX very high, and it's down 18-20 dB in the crossover at 900 Hz, NBD, I suppose.

For the U driver, the first thing I'd want to do after basic measurements is a CSD plot, then a shaped sine test at 800 Hz, and higher, of course.

The ER18RNX has a beauty all it's own..,,. value with fairly stellar performance.

Now another interesting driver with a similar non-descript cone but much different engineering is that Vifa NE180W-04. I'd be a lot happier if it was an 8 ohm driver, though, for making MTM's with 4 ohm sensitivity.

And why call the 6-1/2" version a full range driver, and the 8" version a subwoofer? Is that a PE thing? The 8" looks usable in a Duelund with CF of 800-900 Hz, and the impedance curve is surprisingly flat. Heck, you could probably do a two way at 1500 Hz with the right tweeter, LR4, though I might not like the off axis behavior, due to the crossover- the driver is surprisingly good according to the supplied plots. Four of these in series parallel would move a lot of air, but probably require a big box, unless you elected to do without the box.

[Jed]

This woofer is brand new and I don't think Zaph has tested it yet (but he tested the U16 IIRC). Here's a link to the pdf: http://www.seas.no/images/stories/pr..._datasheet.pdf

You're right I was thinking of the U16, not the U18.

[Finleyville]

It'll be a dark day before you pry the ER18RNX's out of my cold dead hands....

Off topic alert!!

I'm curious, why do you like the ER18RNX's better over (my favorite) L18's?

[Jed]

It has a better motor for one.

[Jonasz]

Lower low frequenzy distortion.

L18 H1224


ER18 H1456

[SpeakerGuy]

Which designs based on either the U18 or ER18 would be most likely to not need crossover adjustment switching back-and-forth between these two woofers? Would be interesting to do some A/B listening comparing the two!