SEAS driver choice for first build and some xMax problems

Hey guys, I have been reading a lot of your discussions and I recently joined to be able to discuss some things in more detail.

I am building my first speakers, they will be a curved bookshelf design, with some similar shapes to Sonus Faber. They will be front ported in a similar design to the TAD speakers and I will be trans laminating CNC cut wood like the TAD Reference Ones.

I would like to use an Aurum Cantus G2 ribbon tweeter from the 90s but I am willing to change this if I get some different recommendations.

My question, and problem so far, is woofer selection. Any woofers I choose seem to hit Xmax pretty bad in my 650 cubic inch enclosure (final enclosure will be between 450 to 700 cubic inches depending on driver selection).

The first driver that did not hit Xmax in my design was a SEAS 7" Curv woven poly. All tho it can go up to 4000hz, I read that I should go with a smaller woofer to match a ribbon tweeter that only goes down to 2.5k hz, is this correct?

So I found some SEAS 5" Magnesium woofers, the Excel W15CY-001. But these hit xmax in my box no matter what I do. I do not want to reduce the enclosure size too much because I would like to keep a nice bass extension.

Which of there two woofers would you guys recommend? And is there anything I might be doing wrong in WinISD that makes my drivers hit Xmax at half their rated wattage? I see similar designs online with the same drivers so I do not know how other designs can pull it off while I seem to be hitting Xmax in my simulations.

Other drivers I had my eye on are the 6.5" AC-165 Aurum Cantus Kevlar and Carbon fiber woofer and the Kartesian Wom165 MS or Wom145 MS.

Thanks you very much in advance.
 
frugal-phile™
Joined 2001
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Aurum Cantus G2 ribbon tweeter

I rally liked the ons i had. They need to be crossed higher than many like.2,5 kHz is really pushing it.


Not something that is comaprable beween makers since there is no clear definition on how to determine xMax. 1-way is more proper then p-p.

There are zillions of decent midBasses. One that is happy up to a 3k+ XO are rarer. Search deeper.

dave
 
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Thanks for the links, this looks like a very similar build to what I am trying to do, I believe I saw this build a few days ago when I was doing research. I wonder how come I get Xmax issues when people are building very similar builds without an issue...

Do you think its a good option to go ahead with the Seas magnesium woofers? I found them at 199 usd on sale right now. Why do you recommend the U18 instead? Someone told me the Seas Magnesium are old and that there are better cheaper options today, but I personally am not finding any modern better solutions other than potentially the U18 Curv. (But I read a lot that Poly woofers have too much damping so I am hesitant, but since the Seas are woven poly, maybe that is different).
 
There are zillions of decent midBasses. One that is happy up to a 3k+ XO are rarer. Search deeper.
I am looking for something metal or woven, I really like the B&W carbon fiber on my CDM1SE's. I also read that Metal pairs better with a ribbon tweeter, and that ribbon tweeters are difficult to make them sound not too separated from the woofer. I look on parts express, madison sound and solen. Is there anywhere else I might be able to find more woofers? Thanks a lot.
 
frugal-phile™
Joined 2001
Paid Member
h1571.jpg


Those specs are often optimistic.

I abandoned typical tweeters a long time ago, i usually onbly pay attention to how it does up to about 1kHz (for a 250-400 Hz XO) so pay little attention to what they do higher except that i like to see little or no ringing.

h1571rev3.jpg


A steady rising response up to about 3kHz. You’d have to flatten out the response in the XO and the natural 3kHz roll-off could be used as part of the filter. Beyond my pay grade.

A 7 litre box can work, in my miniOnken alignment. For a typicalreflex 15 litres would be suggested. And trying to physically fit a 7” driver in a 7 litre box could be problematic.

Wouldn’t be my first choice.

dave
 
You can only push a small driver so hard. A 5" mid-woofer probably isn't going to want to be pushed beyond 25w anyway. If you want more SPL's, then reassess your design goals.
Oh okay thanks, yeah I guess I don't have a lot of experience with smaller drivers. Is there any reason I would want more SPL? I am using these as computer speakers and music listening in a pretty small room. I occasionally turn the volume up a bit louder but not any extreme levels as far as I am aware. My current Amp is a Kenwood B1 and C1, rated to 100W RMS.
 
frugal-phile™
Joined 2001
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Do you have any idea why I could be hitting Xmax in WinISD in such a small enclosure at 35w or 40w?

Maybe because it is a relex. Can you post your sims?

Personally i prefer paper cone woofers, there is a whole lot more to keeping thiongscoherent than what theh cones are made of. You seem to be running into generalizations that are only valid in specifoc cases (ie they shouldnot be generalizations)

The first thing i did to solve the voiving issues was toos the tweeter and move the XO down to under 500 Hz.

dave
 
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A steady rising response up to about 3kHz. You’d have to flatten out the response in the XO and the natural 3kHz roll-off could be used as part of the filter.
That's great info Dave, I appreciate it.
A 7 litre box can work, in my miniOnken alignment. For a typicalreflex 15 litres would be suggested. And trying to physically fit a 7” driver in a 7 litre box could be problematic.
Maybe I have the volume calculated wrong because these speakers I designed aren't small at all. Maybe its the curve reducing the volume too much. I think I was around 10L when I was measuring earlier. I could go bigger. One reason I was very attracted to the 5" seas magensium woofer was that I could try and reduce the size of the box down to those 7L or so. I will remeasure the volume when I get back home from work. If I try different tweeters that could comfortably go down and crossover with the Seas 5" magnesium woofers, and I ignored the Xmax problem, do you think the Magnesium woofers would be a better option over the Curv woofers? I know I would probably have to hear both to know which I prefer, but since that is not an option I am comparing to other builds and speakers from manufacturers, and I don't think those Curv woofers are considered as high end and performing as the Magnesium ones. Its also Seas Excel line vs Prestige line and I think Excel is supposed to be better (so I would rlly like to use the Excel magnesium drivers if they are supposedly better, unless you think otherwise, and adjust the rest of the build). Thanks again for the input!
 
frugal-phile™
Joined 2001
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I am using these as computer speakers

A compleelty differen situation.,

If you get to even a few watts you will be pushing things. More typical would be milliWatts. And near-field a 2-way often has coherence issues, you aren’t far enuff away from the drivers to have them meld.

P7HD works nicely in a 9 litre miniOnken. It won’t beat the AC up top (but you can always prop the G2 on topandplay with it… easier if you have the rectangualr bezel), but i expect will smoke the combo you suggest in terms of midrange performance and coherence. And in 9 litres it goes as low as the SEAS, just won’t play as loud.

dave
 
Is there any reason I would want more SPL? I am using these as computer speakers and music listening in a pretty small room. I occasionally turn the volume up a bit louder but not any extreme levels as far as I am aware.
For the desktop, you would only need a few watts, even with relatively inefficient speakers. I've been running Mark Audio & Fostex based single driver speakers on my desktop for many years now. I doubt I'll ever go back to 2-way speakers. Even with the little 5L A6p boxes that Dave designed, I could melt my eardrums with 18 watts/ch. no problem.

jeff