I was just cruisin' around the site when I came across the "How To" section. In the part about differentiating between active and passive crossovers, something was said about different ways to block different frequencies. For example you would use a cap to block lows, and a choke to block highs. I knew that an inductor was also called a choke, but I've never heard a transformer referred to that way. I always thought its purpose was for stepping up/down voltage to a desirable level. Can transformers also be used as filters?
Pinch
I know this is nit-picky but I am curious. :)
Replies (2)
admin on 10/3/2003 13:27:57
Transformers have two or more windings. Chocks and inductors have only one.
Swez on 10/3/2003 13:38:50
Transformers do just as you say... they step up voltage while stepping down current or can do the reverse, depending on the design and winding configuration.
Caps are generally used to block DC and low frequencies. Inductors are used t0 filter out highs and pass lows.
Simple passibe filters (1 cap or inductor coil) net a -6 db drop in signal based on value of the coil and resistance of the load. More complex filter networks use a combination of caps and coils as HP/LP filters. You can do -12dB, -18dB, -24dB filtering if desired.
For most car audio applications a 2nd order Butterworth or Linkwitz-Riley networks are the norm. However, if one really needs to have a high slope to protect high cost tweeters, a -24dB filter is common. (4th order filtering network)
This is a very complex subject and if you wish to learn more about what all goes into high end filters, GOTO:
http://www.eatel.net/~amptech/elecdisc/xoorder.htm
Have fun,
Swez
PS Bet this will stir your curiosity (blow your mind) more than you first thought... lots to chew on and why crossover design engineers are so valuable.
Pinch
I know this is nit-picky but I am curious. :)
Replies (2)
admin on 10/3/2003 13:27:57
Transformers have two or more windings. Chocks and inductors have only one.
Swez on 10/3/2003 13:38:50
Transformers do just as you say... they step up voltage while stepping down current or can do the reverse, depending on the design and winding configuration.
Caps are generally used to block DC and low frequencies. Inductors are used t0 filter out highs and pass lows.
Simple passibe filters (1 cap or inductor coil) net a -6 db drop in signal based on value of the coil and resistance of the load. More complex filter networks use a combination of caps and coils as HP/LP filters. You can do -12dB, -18dB, -24dB filtering if desired.
For most car audio applications a 2nd order Butterworth or Linkwitz-Riley networks are the norm. However, if one really needs to have a high slope to protect high cost tweeters, a -24dB filter is common. (4th order filtering network)
This is a very complex subject and if you wish to learn more about what all goes into high end filters, GOTO:
http://www.eatel.net/~amptech/elecdisc/xoorder.htm
Have fun,
Swez
PS Bet this will stir your curiosity (blow your mind) more than you first thought... lots to chew on and why crossover design engineers are so valuable.
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