W18E001 new vs old

[tktran]

Hi,

Can anyone tell me if they've measured any differences between the new and old SEAS W18-E001 drivers?

The new one is identifiable via the rubber boot over the magnet.
The old ones have the copper plated magnets.

In the older versions, there seems to be a droop between 1-3Khz. The droop is most noticable at 3KHz, right before the cone takes off and hits the stratosphere by 5KHz.

Also, has been a drift in the frequency (and intensity) of this breakup mode?

regards,
Thanh.

[JonW]

Hi Thanh.

Not exactly what you're looking for, but it might help a little bit...

I've been looking at the Seas W15CY-001 for an upcoming project (among other drivers). As usual, Zaph provides lots of good data. Here he has measurements of a newer version in 2007:

http://www.zaphaudio.com/5.5test/

There's a significant droop at ~3,000-6,000 Hz. Then the usual spike, etc. above that.

From 2004, there are tests here:

http://www.zaphaudio.com/oldversions/

The droop is less pronounced and it might be usable up to ~4,000 Hz. Just based on the frerquency response.

In both cases, the distortion looks best ~200 - ~1,000 Hz. Above ~1,500 Hz and it gets ugly. So it looks like some small changes over time.

[tktran]

Hi Jon,

Thanks for the suggestions. Actually, it was John Krutke who first sensitized me to the differences between the new and old W15CY.

I think the similar factors may be at work for the W18E drivers.

I am doing my own research about this too, and will report back here, if anyone else is interested.

regards,
Thanh.

[Jed]

Hi Jon,

Thanks for the suggestions. Actually, it was John Krutke who first sensitized me to the differences between the new and old W15CY.

I think the similar factors may be at work for the W18E drivers.

I am doing my own research about this too, and will report back here, if anyone else is interested.

regards,
Thanh.

Dave Ellis noted some differences in the old versus new W18s in his speaker. I think that is why he discontinued the Seas version of his speaker. You might want to contact him directly to see what he noticed.

As for the W15, you can't determine the difference in FR by looking at the boot. There is a little "lip" on the cone where it reaches near the voicecoil, if it doesn't have that, it's the old version and has a lower breakup peak. I have a quad of W15s that do not have the rubber boot, but matched exactly with the new rubber boot version- cone breakup is at 8.3kish.

Jed

[tktran]

Ok I think I've completed my research.

I've only had a chance to measure 1/4 of my drivers, but it rings at 4.75Khz (+/- 500Hz), as which is virtually the same as that predicted by the current SEAS datasheet.

Other people have measured differientvalues from 4.4KHz-5KHz which IMHO is a very tight tolerance (~5%)

However, if one uses a narrow notch filter, getting it to strike precisely at the intended point is best achieved with acoustic and electrical measurement tools, rather than CAD simulations alone. Without it, the tolerance with caps and inductors (often 5%) in the LCR can result in a mis-hit.

I had to fine tune my notch filter, and was rewarded by the effort.

I often read comments that some people prefer the sound without a notch filter. Part of the appeal of the "detail", "magic" or "sparkle" may be actually induced by the resonance. As soon I knocked out the resonance, gone is the usual sound.

It may be less "interesting", but for me it just opens up 50% of the music collection which were previously avoided. The magnesium W18E becomes as versatile as any other cone...

regards,
Thanh.

[jkrutke]

I've got some new vs old plots from Hobby Hifi magazine if that interests you, I can email them to you.

But in summary, new peak was at 5kHz, with more output in the 2-3 kHz area. Old peak was at 4.5kHz with a little droop between 2-3kHz (like you mentioned) and a little smoother response below that.

One thing I can say about all the magnesium cones is that they have very good piston behavior within their passband.

[tktran]

Hi John,

That would be great. The usual email address works until the end of this year.

best regards,
Thanh.

[dlr]

One thing I can say about all the magnesium cones is that they have very good piston behavior within their passband.

There wouldn't be much reason to use them otherwise, would there?
Dave

[john k...]

Here is the data from SEAS for the new and old W18e-001

[tktran]

Hi John (K),

Thanks for that. Hey when you put it side to side like that the differences are clear. I don't know why I didn't think of that.

I keep trying to overlay one over the over, which mades things even more confusing.

I also did a SPLTrace from the current SEAS datasheet, old SEAS datasheet, as well as the plot from the old Madisound PDF catalog, as part of my "research" :B

I've got all the old PDF datasheets (with harmonic distortion plots)
if anyone is interested.

regards,
Thanh.

[johngalt47]

Crossover?

What did you end up with for a crossover?

[eboleyn]

Hi John (K),

Thanks for that. Hey when you put it side to side like that the differences are clear. I don't know why I didn't think of that.

I keep trying to overlay one over the over, which mades things even more confusing.

I also did a SPLTrace from the current SEAS datasheet, old SEAS datasheet, as well as the plot from the old Madisound PDF catalog, as part of my "research" :B

I've got all the old PDF datasheets (with harmonic distortion plots)
if anyone is interested.

regards,
Thanh.

Turns out I have the old SEAS W18E001 drivers (the ones with the copper back, model E0018-08, no "S") in some speakers I purchased.

Could I get the old SEAS datasheets from you? (and the old plots would be useful too)

(you can PM me with it if posting it here is inconvenient)

Erich Boleyn