PLC*1 mkII with a subwoofer

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Leifer

  • Jr. Member
  • Posts: 31
PLC*1 mkII with a subwoofer
« on: 30 Jan 2019, 04:49 am »
The PLC has two main outputs.

My subwoofer will be the Dynaudio Sub 3.

https://www.dynaudio.com/home-audio/sub/sub-3#tech-specs

(I also have the CIA C*100s amp, for my main 2ch bookshelf amplification.)

Basically, this powered Sub has stereo line-level inputs, and then stereo line-level outputs. In other words, the Sub unit filters the input to produce it's bass (low pass), and sends a filtered output (high pass) to my CIA amp and bookshelf speakers. Volume and crossover freq is select-able (including "flat"). It also has a single LFE input for pre-filtered bass, such as a surround HT system, which currently I do not have access to.

What would be my preferred setup ?

Do I pass all signals through passive PLC #1 outputs directly to the Sub's line inputs, then the Sub's outputs to the C100s amp + speakers ?
Or do I send the Sub the PLC's #2 outputs directly to the Sub, and adjust the sub for proper balance ? (this means the high-pass is not in effect).


(I couldn't find the Sub's input or output impedance, at the line-level)



CIAudio

Re: PLC*1 mkII with a subwoofer
« Reply #1 on: 30 Jan 2019, 05:15 am »
The easy way is to feed the output of PLC into the sub, then back out (high pass) to  C-100S. The bad thing about this approach is the signal is now passing through an active crossover (another amplifier), so the quality of this amplifier is important.

I would recommend using the active crossover for the subwoofer only, then a passive filter at the input of C-100S to roll off the lowest bass frequencies.
This requires changing some internal part values but doesn't add more junk in the signal path.
Give me a call if you'd like to discuss it further.

Leifer

  • Jr. Member
  • Posts: 31
Re: PLC*1 mkII with a subwoofer
« Reply #2 on: 30 Jan 2019, 11:35 am »
Thanks so much.
I have made passive high pass filters before.... good film caps and  vishay foil resistors inside a tiny metal box with RCA's in and out (inline). Not very advanced, but measurable on paper.



I've also previously made (have) an active 24dB Linkwitz/Riley filter, with 0.5% polystyrene caps and similarly matched resistors......adjustable cutoffs via jumpers.



....that's just my history.....I'll contact you for current recommendations regarding these (CIA) units.  :)


opnly bafld

Re: PLC*1 mkII with a subwoofer
« Reply #3 on: 30 Jan 2019, 01:50 pm »
I wouldn't worry about a high pass filter with Dyn 40s (unless you listen at very high levels).

Leifer

  • Jr. Member
  • Posts: 31
Re: PLC*1 mkII with a subwoofer
« Reply #4 on: 30 Jan 2019, 08:58 pm »
Quote
I wouldn't worry about a high pass filter with Dyn 40s (unless you listen at very high levels).

I will try this first.
...trying the easiest way first........always start with the easiest and most available/logical.
Thanks for the reminder.

Also, this can make sense....
One reason for a 2.1 system  highpass, is to help relieve the main speaker from potentially struggling with too much low-end movement, and then the Sub take (cross) over.
But if the main speakers never get stressed by playing loud or hard.......then why add a filter if it's not needed ? .... just find filter heaven by adjusting the (adjustable) Sub .
It's a plan.

So for right now, PLC output #1 will go directly to the C100s amp to stereo speakers.....acting as if there is no Sub.
And #2 output goes to my Sub. And I try to adjust the Sub for best sound (crossover, placement, and volume). That may be enough.
Tests will tell.

......but, I'll eventually need to know what it sounds like filtered too, for comparison. (in comes a temporary  passive filter)
I'll have to find that online filter calc...... and solder one or two up.