
Home  Forums  Rules  Articles  diyAudio Store  Gallery  Wiki  Blogs  Register  Donations  FAQ  Calendar  Search  Today's Posts  Mark Forums Read  Search 
MultiWay Conventional loudspeakers with crossovers 

Please consider donating to help us continue to serve you.
Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving 

Thread Tools  Search this Thread 
29th April 2013, 05:57 AM  #31 
diyAudio Member
Join Date: Apr 2013


29th April 2013, 11:53 PM  #32 
diyAudio Member
Join Date: Feb 2002
Location: Western Sydney

For the crossover to work as designed, it needs to see the same impedance with the new tweeter as with the old, so the L pad needs to do two things  maintain the total impedance, and incorporate the attenuation you require. (It may be simpler to use a variable resistor & replace with two fixed resistors once you've found the level required)
__________________
Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency 
30th April 2013, 05:24 AM  #33 
diyAudio Member
Join Date: Oct 2008

The beauty of an Lpad is that it will partially flatten out the impedance, bringing it closer to the Lpad design impedance. The more you attenuate, the more it will do this. For example, if you pretend the tweeter is a four ohm tweeter and calculate the Lpad for 4 ohms and attenuate by a fraction of a dB, it will still look like an 8 ohm tweeter with all its peaks and curves....but if you attenuate by several dB then it all begins to look just like a 4 ohm resistor without the peaks and curves.

30th April 2013, 05:42 AM  #34 
diyAudio Member
Join Date: Apr 2013

Thanks for comments, but I still didn't get practical solution for problem I have. I want to attenuate by 5db and cut impendance in half in same time.

1st May 2013, 06:59 PM  #35  
diyAudio Member
Join Date: Nov 2003
Location: Brighton UK

Quote:
(1.8R series and 3R parallel gives 4 ohms and 5dB.)
__________________
There is nothing more practical than a really good theory  Ludwig Boltzmann When your only tool is a hammer, every problem looks like a nail  Abraham Maslow Last edited by sreten; 1st May 2013 at 07:05 PM. 

1st May 2013, 07:23 PM  #36 
diyAudio Member
Join Date: Apr 2013

Sounds good. Thanks. Still curious what would I get wit only 8 ohm in paralel. In case I'm affraid of messing up the signal line to spraker ;)
? 
1st May 2013, 07:38 PM  #37  
diyAudio Member
Join Date: Nov 2003
Location: Brighton UK

Quote:
Hi, 4 ohms with no attenuation, rgds, sreten.
__________________
There is nothing more practical than a really good theory  Ludwig Boltzmann When your only tool is a hammer, every problem looks like a nail  Abraham Maslow 

3rd May 2013, 11:00 AM  #38 
diyAudio Member
Join Date: Oct 2008


3rd May 2013, 05:22 PM  #39 
diyAudio Member
Join Date: Apr 2013

Well, I would't like to put many elements to signal path. I wouldnt like to spoil it. However, resistors are passive elements. Maybe it's just my imagination.... :p

3rd May 2013, 07:43 PM  #40 
diyAudio Member
Join Date: Oct 2008

There is a difference but it's not easy to notice. It's probably best to put in everything you need.

Thread Tools  Search this Thread 


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
LPad variable resistance dial in tweeter volume  kach22i  MultiWay  9  4th January 2012 02:42 PM 
The down side to adding series resistance to horn drivers  AllenB  MultiWay  33  29th September 2011 10:16 AM 
Info on Resistors / series resistance  one1speed  Full Range  7  24th February 2006 01:29 PM 
Measureing Cable & Crossover Series Resistance  Allan  MultiWay  12  3rd January 2005 11:01 AM 
Add Series Resistance of the Wire in TS measurement?  r_s_dhar  MultiWay  1  27th July 2002 11:06 AM 
New To Site?  Need Help? 