Aurum Cantus woofers for a 2way speaker

[qubix]

I have searched the forum for opinions, but haven't found any.

Hi. Has anyone had any experience with the following woofers:

- Aurum Cantus AC-180F1
- Aurum Cantus AC-165

i'm thinking about building a 2way or 2,5 way speaker with a crossover at at least 2.8 kHz. Would prefer the 180, as probably bass would be satisfactory and i could get on without the ".5" way....

The high tones would be put through Aurum Cantus G2Si or one of Usher domes. The woofers are to be compared with Usher 8945-P. It is my current suggestion, but it lacks midrange if cut at 2.8 kHz with break-up filters.

the data for AC woofers is here: http://akkus.com.pl/index.php?grupa=...&lang=en&dh=dt
in Polish, but i'm sure u guys learn fast

[qubix]

noone did have any experiences with those?

any suggestions? even like "take the ushers, don't ask why"?

[Euphase]

Originally posted by qubix
i'm thinking about building a 2way or 2,5 way speaker with a crossover at at least 2.8 kHz.

The high tones would be put through Aurum Cantus G2Si or one of Usher domes. The woofers are to be compared with Usher 8945-P.

I don't have any experience with the Aurum Cantus woofers, but have with the Usher 8945P and Usher 9950-20 tweeter.

I wouldn't suggest a 2.8Khz xover on the 8945P, obviously the breakup mode and also distortion is not as good as at 2Khz and higher frequencies than it is at say 1Khz and below. And that's typical for most woofers.

Looking at the FR and impedance graphs of AC-180F1 it also has a breakup at 3Khz. So don't think that's a good candidate either for 2.8Khz xover. AC-165's FR doesn't look to easy either.

It doesn't look like any of the woofers on your list is a good candidate to match the ribbon.

So my suggestion, use the 8945P, very low distortion motor, and nice midrange IMHO, but needs to be xovered low, and it has a bump at 1Khz that needs to be brought down. For tweeter use the Usher 9950-20 or any other low xoverable 28mm domes.

Actually this is what I did and you can see my design here,
http://www.euphase.com/design/km-u2/KM-u2.asp Xovered at 1.9Khz 4th order LR.

I use the 9950-20 as tweeter, and like the sound of this 2-way very much. 8945P's bass is very good, actually amazing but that's my opinion. It is a 2-way but comes close to a full range sound.

[qubix]

thanks for the info.

I was thinking about making the same project. The Xover seems to be well thought of. Maybe you have got some measurements of your project? For use with SpeakerWorkshop.

[Euphase]

your email is not working

[qubix]

that's no email... that's jabber ID. jabber is an open IM standard, and yes, the JIDs look a bit confusing. The forum's personal messages work ok to contact me. my email address is qubix@random.7bulls.spam.com (remove random and spam).

Your project at Euphase.com would certainly be the choice to try out if i but the usher speakers. I'm still searching for 16-18 cm woofers that would offer very good midrange quality and have very little cone break-ups to be cut by XO at 3-4kHz. Bass is not that important, as i would try to make a 2.5 way, and am not a techno enthusiast. The audax carbon fibre HM170C0 was very interesting, but they have stopped making it.... and i'm not financialy able to buy phl.

Why i want to avoid XO at 2 kHz? because human ear is most sensitive to distortions between 1 kHz and 4 kHz.

Why i don't want a 3way then? I already have one! seas mp14 coax and vifa p21wo39.

[Euphase]

Originally posted by qubix
. I'm still searching for 16-18 cm woofers that would offer very good midrange quality and have very little cone break-ups to be cut by XO at 3-4kHz.

One woofer that comes to my mind is VifaXT18 woodfiber cone. I haven't used it, but I read others opinions on this that it has a nice and easy to deal with midrange.

There are always trade offs, at 3-4Khz xover point center to center distance between woofer and tweeter becomes larger than the wavelength of the xover frequency, resulting in more vertical dispersion problems and IMO this makes it harder to blend the woofer to the tweeter seemlessly. Also 6-7" woofers start beaming before 3Khz, a 3-4Khz xover also results in a worse horizontal dispersion than a 2Khz xover with the same drivers.

My current thinking is, if I had a tweeter that would handle 1.5Khz, I would use a 1.5Khz xover point.

[qubix]

i see your point.... furthermore, the higher the XO point in 2way, the more problems with doppler effects occur.

[qubix]

another thing... about the Euphase Usher 2way, and the tweeter. You have used Usher 9950-20. Usher makes a cheaper one, the T-9930, which according to the producers data, produces LESS distortion.

Compare
http://www.akkus.com.pl/index.php?gr...&lang=pl&dh=dt
http://www.akkus.com.pl/index.php?gr...&lang=pl&dh=dt

sorry for the page being in polish, but it seems that's something's not right with www.usheraudio.com webpage.

[Euphase]

Originally posted by qubix
i see your point.... furthermore, the higher the XO point in 2way, the more problems with doppler effects occur.

Well, again it is a trade off between how much doppler at woofer vs how much doppler at tweeter; decrease woofer doppler, increases tweeter doppler. I haven't run any numbers though. I haven't looked into doppler distortion seriously yet. I read a few things about it, some claim inaudiable, some says it is a problem....

Originally posted by qubix
Usher makes a cheaper one, the T-9930, which according to the producers data, produces LESS distortion.

I haven't listened or measured 9930. Those distortion plots can only give some idea, but not tell too much. First of all what drive level was used is not obvious. Still there is one thing that catches my eye in there, 9950's 3rd order distortion doesn't rise with rising frequency, 9930's does rise with rising frequency. This is exactly what I would expect from the difference between the two drivers: 9950 has a faraday cap that covers the pole piece, 9930 doesn't.

Consider this, AFAIK Usher uses 9950 at their flagship speakers, not 9930
This is speculation on my part, for some people 9930 may sound more airy and detailed and 9950 more dry. The additional 3rd order distortion generated at high frequencies will cause this. It looks like though 9930's 2nd order is better at lower frequencies, but again I would like to see more measurements with well defined drive levels etc.