How to design Crossover circuit of the loudspeaker using accuton ceramic driver unit?

Hello everybody, I have a plan to build a three-way loudspeaker using accuton ceramic unit. Now I have some questions of the crossover design of those ceramic unit.
My plan is:
High:C13 Mid:C79 Bass:C95X2

Which order is better? From the factory homepage, they said it can use the first order design. But I have heard that first-order design may damage the unit. Is that truth? The first-order design can bring the natural sound or hign-order design can bring the more accurate sound?

Another question is the crossover point. The point between high and mid is about 3.5KHz. The point between mid and bass is about 400Hz
Are the seting of these points good? I'm afraid of that C79 cannot sustain the 400Hz point or I need to use 5" driver.

Thank for your opinion and suggestion and I'm sorry for my poor english writng and description skills.
 
I can't advise you directly, but if you haven't already please visit the Humble Homemade HiFi site and look at the all Accuton "Soup" loudspeaker:

http://home.hetnet.nl/~geenius/Soup.html

Tony's driver selection is different from yours, but he is a very experienced and knowledgable designer (not to mention his speakers are gorgeous) and he goes into great detail about his crossover designs. You may even decide you want to build the Soup yourself. I'm sure he will help you with your project if you ask.

Hope this helps.
 

LaMa

Member
2002-09-04 11:43 am
NL
Don't use a x-over without a notch on the resonance frequency of the driver(s), although the accuton's are quite behaved for a stiff cone they need some attenuation at their resonance frequency.

In my experience the c95 can quite easily be filtered by an series coil and a shunt LCR (parallel filter topology) . When done right this combination will yield appr. 3rd order acoustical slopes. So you have to cross around 2kHz (above this freq the midwoofer starts to beam).

Most accuton tweeters are highly damped with ferrofluid, so when you cross high enough there is no need to notch it's fundamental resonance.

However why do you choose to use the c79, when you most probably can get a more coherent speaker by directly mating the c95 with the c23 tweeter. The way you do it, it's more difficult to get right.

Also I suggest to atleast get your drivers measured in YOUR cabinet, so you know the response and can design the x-over accordingly.

About the designs of geenius, his designs are not always succesful. Three designs he participated in, and which I heard, were not sounding very well (to put it mildly) and his cross-over for the soup does not promise very much (the soup is under debate on a dutch forum).

To wrap it up: When you use sophisticated drivers, you also need sound engineering to get things working. No "cut and paste" filter topologies can be used (actually they can never be used, at best you can get away with it, when more friendly drivers are used).
 

LaMa

Member
2002-09-04 11:43 am
NL
Mr Evil said:
I wish I could afford to buy drivers like that:(

For such excellent drivers, surely it would be an injustice to use a passive crossover. Also, since they are pretty well behaved over a wide bandwidth, perhaps a subtractive crossover of some sort?


A well designed passive cross-over is still a very good option, but you have to know how to do it.

BTW you don't have to buy accuton to build a very nice speaker, IMHO Accuton is not the holy grail, just very expensive ;).
 
Hi Kevin,

Creating a crossover for the Thiel/Accuton units is not straightforward. The units have severe break-ups in their upper frequency range, and their response curves have frequency response deviations in their operating range. This requires filter design with compensation circuitry and carefully chosen crossover frequencies. Text-book filters will hardly work here.

You could have a look at my recent topic about the Milestones loudspeakers. They describe a design of a speaker with a Thiel/Accuton C^ 12, C^2 79 and C^2 220-T6.

http://www.diyaudio.com/forums/showthread.php?threadid=62555&referrerid=381

Yesterday evening I've assembled a new crossover filter, which I think outperforms all the previous ones made. I'll update the info in the forum and website in the coming days (today?), so stay tuned!

Marc
 

LaMa

Member
2002-09-04 11:43 am
NL
marche said:
Hi Kevin,

Creating a crossover for the Thiel/Accuton units is not straightforward. The units have severe break-ups in their upper frequency range, and their response curves have frequency response deviations in their operating range. This requires filter design with compensation circuitry and carefully chosen crossover frequencies. Text-book filters will hardly work here.

You could have a look at my recent topic about the Milestones loudspeakers. They describe a design of a speaker with a Thiel/Accuton C^ 12, C^2 79 and C^2 220-T6.

http://www.diyaudio.com/forums/showthread.php?threadid=62555&referrerid=381

Yesterday evening I've assembled a new crossover filter, which I think outperforms all the previous ones made. I'll update the info in the forum and website in the coming days (today?), so stay tuned!

Marc

Marc,

interesting speaker! I don't have that kind of woodworking skills :( And again like you said designing a cross-over is not easy (in general!).
 
Thanks guys for your reply.:)

To Mr. Marche , very amazing and spectacular project. In fact , the reason I would like to use ceramic driver is I have chance listening the following loudspeaker:

Avalon Opus Ceramique
[IMGDEAD]http://www.audio-designs.co.il/Products/OpusCeramique.jpg[/IMGDEAD]

Lumenwhite Whitelight

[IMGDEAD]http://www.acousticdreams.net/lumenwhitewhitelightspeaker250301.jpg[/IMGDEAD]

Marten Design Coltrane

coltrane.jpg


Marten Design Coltrane Alto

[IMGDEAD]http://www.dagogo.com/sitebuilder/images/Coltrane-Alto2-453x443.jpg[/IMGDEAD]

Kharma Midi Exquisite

[IMGDEAD]http://www.avguide.com/inthenews/CES_2005/images/wayne/edited/KharmaMidi.jpg[/IMGDEAD]

Those speaker sound very good. But they are very very expensive in Taiwan , for example the real price in audio sore of Avalon opus ceramique is about USD:17000(higher than list price in USA!!!)
But the price of driver unit is close. So I think to build a speaker is a good ideal and it will be an interesting experience.
 
The Kharma loudspeakers are one off the worst loudspeakers I have ever heard, flat, dull and uninvolving, even my Sony all in one set in my kitchen does a better job, but that's just my opinion, others might like it. I have heard the Avalon twice at a show but on music so utterly boring that I really can't tell how it sounds.

I have played around with Thiel/Accuton drivers myself back in the days when I thought anything that expensive could only be the best of the best, now I know it ain't. Don't let the price fool you. Buy them if you like them offcoarse.