Passive Low Pass

[kevatt]

I am looking to build a low pass (passive audio ) filter i am looking to make a more radical design other than the ones available from the shop shelf possibly incorporating it into the cabinet design i wish to filter as much mid as possible just leaving the low stuff (sub bass frequencies)
would be interested in any input that anybody may have the area of power i am looking into is from 600watt to 1k/1.5k this will feed into 15/18/20 inch drive units

 

[Nigel Goodwin]

Presumably you're talking about crossovers at speaker level?, so you're talking VERY expensive, and you will lose a considerable amount of power as well. Assuming this is a stereo system?, and a mono sub-woofer, you also need two of them, and a special twin voice coil sub-woofer. A passive filter will also seriously reduce the damping factor, and the more complicated the filter, the more all this factors affect it.

There are good sound reasons why it's normal to use electronic crossovers and seperate amps!.

 

[Super_voip]

from memory you'll lose about 6dB wich is hell of a lot in a 600W system

 

[kevatt]

reply

the system would be running three amps 2k for the subs 1k for the mids & 600w for the tweets i have active cross overs but just it would be worth looking at as if you dont have an ideas things never move forward is there any links that could be recommended that give an in depth principle of passive filters

 

[Nigel Goodwin]

If you've got active crossovers it's not worth looking at, an active crossover is far, far, far, better than a passive one. What would you hope to achieve by adding a low spec passive filter to the output of a far higher spec active one?.

 

[kevatt]

a local store supplier of cabinets ETc has a supplier of pretty bog standard filters and i thought that if a new radical design could be developed there is and area that i could exploit lets face it they all are basically copper windings the

 

[Nigel Goodwin]

a local store supplier of cabinets ETc has a supplier of pretty bog standard filters and i thought that if a new radical design could be developed there is and area that i could exploit lets face it they all are basically copper windings the

So you think you can defeat the laws of physics?, and beat the worlds best designers over the last 80 years or so?.

I suggest you go and learn some basic electronics, the formulas are fairly simple (if you can do basic algebra? - and presumably pretty well anyone in double figures can?) - "you canna change the laws of physics" (to quote Scotty from Startrek).

 

[Super_voip]

Just how different

My speakers are now very old Urei 811's, and the last time I saw a price on new ones they were $11,000. The sound is awesome, of course I'm going deaf now but the crossovers are huge, extra large inductors etc. 12V lamps are used to indicate excessive input. The lamps also act as a limiter as the filiment heats the resistance increases. Yes I've had them light up, see above re:deaf. These speakers were designed by the same person that invented the PZM(pressure zone microphone) so I'd say he strayed from the convention path a little with these speakers.

 

[Super_voip]

**broken link removed**
has all the schematics for a lot of older speaker crossovers and amps, maybe something old will be new again.