Xover modification: (leap for dummies?) help!

[francorovereto]

Hi,

I write hoping there is anybody can help me with my diy project.

Loving Dynaudio sound, I'm starting building a two-way speaker using Dynaudio esotec d260 tweeters and a (car) woofer: Dynaudio esotec mw172.
here are the specs:

http://www.gattiweb.com/images/dynau...-d260_data.pdf
http://www.gattiweb.com/images/dynaudio/MW172.pdf

I have spent days making sims on winisd, and changed 2-3000 times my meanings. Finally I found a passable solution in a 42 l cabinet vented to 32 hz. I can't exceed this size, my girlfriend could shoot me.

Being totally noob in xover design I would use some old xover schematics of Dyn Aries project, wich use the same tweeter and a relatively similar woofer (similar impedance graph and rise, similar size but sadly different vas, fs etc.)

this is the xover: http://www.gattiweb.com/images/dynaudio/aries_4.pdf
Cabinet will be very similar in baffle dimensions.

Do you think that could be suitable? Is a good xover schematic or simply an old, not so shiny model? It's worth of using (modifiing?) it or create it (even with MAdisound leap service, wich is based on mw170 and not 172)?

I'm lost.
Help.

Franco

[PeteMcK]

as I said before, the specs of the two woofers are close enough that you can use the same crossover (even though I think it's overly complex...)
You can always tweak Rs and the .9mH inductor later.

[tinitus]

Buy a couple of the new 2way Hypex plate amps

Im sure many people would like to help you, but it really is impossible to do a passive xo that way
We might be able to help you in a process to try and learn about it, but its a long journey
And you have to do most work yourself
And be prepared to make mistakes and changes
How many depends on many things

[col]

A good procedure to follow:

Passive Crossover Network Design

col.

[francorovereto]

You all are right. I've read a lot of stuff about passive xover, including the link that col indicate me. Sadly I can't do accurate enough measurements, so my intent was to start from a good model and tweak it by listening and measuring the output from the speaker. The only measurement I can do is acoustical, I have an average mic and a cople programs that will do the job with an average approx.
Impedance measuring remains a problem given the poor accuracy of my multimeter and my poor pc soundcard.
I'd prefer to spent my (little) money in drivers and not in sophisticate measuring tools.
Do you think i'm totally on the wrong way?
I'm not seeking the ultimate perfection, only a good enough balance (given that room reinforcements and resonances can modify things anyway)....I was thinking that dynaudio project were good and refined projects, and only with little tweakings.....

[tinitus]

Originally Posted by francorovereto

Hi,

Loving Dynaudio sound, I'm starting building a two-way speaker using Dynaudio esotec d260 tweeters and a (car) woofer

The important and returning question
Have you already bought these drivers or just decided to ?

[francorovereto]

I have the drivers.
But I could buy a pair of dynaudio 20w75 I found on ebay and sell the MW172 (i bought these on a auction for few bucks). This might be better (i could use the xover schematics without changes) but I don't know if venting the box can affect the balance of it.
Maybe I should modify the R of tweeter attenuation given the db increase of woofers..

[PeteMcK]

you already have ' sophisticate measuring tools' - its called a computer - the rest is easy...
1: download ARTA
2: make this simple jig: AudioBlog: A simple loudspeaker measurement jig for ARTA
AudioBlog
(near the bottom of the page)
3: measure your speaker's parameters

[francorovereto]

Seems interesting. I've read also that the measurements are not so precision-aimed but only indicative (good for the money but really good for a speaker?). It's a reviewer's bad application of the jig or at the end T/s parameters and impedance curves declared from Dynaudio are better?
I've read that calculating a xover inductance or zobel netw. you need very precise values.

[francorovereto]

PS: The chief developer of Audesine says me that with a good math model and manufacturer specs he can give me a good Xover schematic. Should I thrust him?
You all say that at beginning we need measure, measure, measure.....