Do you need a crossover/filter for a sub?

[TheLaw117]

Hi,

You might know I'm working on an LM3886 Stereo amp. I'm a bit antsy you see...

While I'm in the amplifier/speaker building mode. Does anyone actually use a filter for a subwoofer? Is it worth it I mean?

EVENTUALLY, I'd like to get one of those nice 8" HiVi M8a's. Eventually...that is.

Also, is there a special type of amp required? Are 2x bridged LM3886s not good?


Thanks a bunch. Just out of curiosity.

 

[PeteMcK]

yes, you need one; the easiest way: TLS.org | Passive Line-Level Crossover

 

[TheLaw117]

yes, you need one; the easiest way: TLS.org | Passive Line-Level Crossover

I mean only a subwoofer. Just a subwoofer in a box...no other speaker.

Still?

 

[N Brock]

Yes, still. if not the sub will sound poor.

You could use a PLLXO, a passive crossover (more expensive), or an active crossover 9even more $$)

If in doubt you can try it without a crossover, shouldn't hurt anything, but most subs are designed to only play on the lower end.

N-Brock

 

[AllenB]

Do you want your sub/s to be reproducing midrange? Apart from hearing it, if it/they are not close to your mains then you may end up with cancellations (comb filtering).

Unless you build bandpass subs which have inherent physical low pass filtering.

 

[audiobomber]

You may be able to use a sub without a filter if it's strictly used for a Home Theater ".1" channel, with all the other speakers set for full range operation. For any other setup, no way, a sub without a filter sounds horrid.

 

[AllenB]

If I assume by your reply that you are keen to get on with it, a simple inductor with the speaker lead will get you started, and maybe a well chosen electrolytic capacitor across the speaker terminals to go with it. No big deal until you want to start getting exact.

 

[TheLaw117]

Thanks. I won't be building the sub for a while, but I was just curious...

And would I need to use a different type of amp? Or...?