Xover guru needed - help!

[dpaws]

Hi guys, and many thanks for taking the trouble to look.

I'm a newbi to speaker building (CD players and tube amps more my scene) but I know what I want and hopefully this forum will enable me to achieve my dream. I need a floor standing two way design built around the following drivers:

Tweeter: Visaton KE25SC : http://www.visaton.com/en/chassis_zu...otten/605.html

Woofer: Dynaudio 17WLQ Esotec 8 ohm : http://www.gattiweb.com/images/dynaudio/17wLQ_data.pdf

I have both of these presently in a Silverline SR17 cabinet with a padded single order crossover on 2.5K just to run the tweeter in.

I'm using 845SE tube amps so only 24W available

Thoughts: The fr for the Dynaudio looks weak above 2k, particularly off axis. The tweeter looks good down to 1800Hz

1) Can I crossover at 1800 or is the tweeter going to be full of distortion at this range?

2) How do I achieve a clever Xover (like the DIY2000 design) where steep slopes are achieved with minimum components?

3) How much of a crossover can be designed without taking measurements - do you build a basic Xover, measure it and then tweek or do you have to measure the "naked" drivers insitu before you can start?

All thoughts and help very much appreciated - absolutely haven't a clue where to start!

Cheers, Steve

Rainham, Essex UK

ML390S // Unison Research Smart 845 // ???

[dpaws]

RE 3) How much of a crossover can be designed without taking measurements - do you build a basic Xover, measure it and then tweek or do you have to measure the "naked" drivers insitu before you can start?

From Dave Bullet:

The best thing you could probably do now is....
1. Try and find a design that uses the same drivers and copy it (enclosure, crossover etc...)
2. Assuming you cant find an exact design - find 2 designs that share a similar enclosure - and see if you can obtain the frequency response measurements (per driver - no crossover). Regardless of 1 or 2. - you will need to build the enclosure to the same dimensions as that used in the woofer project you got the measurements from. The tweeter will be placed on baffle in the place used for the tweeter design. Put woofers and tweeter as close together as possible
3. Download a crossover modeling program (ie. Speaker Workshop) and load the frequence and impedance plots you obtained in 2.
4. Use the textbook formulas (as you have done via the lalena site) to start with a crossover that suits the will achieve the target slopes you have intended for each driver
5. Tweak until get you get a modeled frequency and phase response that looks good. (Note - this will be good on-axis - who knows what off-axis response problems may be lurking).
6. Build a prototype - with your crossover... and ideally be able to measure its response
7. Repeat from 5. until happy

Great advice Dave - thanks - just need some starting points... help!

[Cal Weldon]

dpaws,

This is a good all around basic designer. It will help with all aspects of the project. Have a look through there and come back with your questions.

http://www.mhsoft.nl/spk_calc.asp