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03-01-2012 Post does not mapped to Knowledge Tree
noviygera


Chicago, IL
Posts 129
Joined on 06-12-2009

Post #: 1
Post ID: 17894
Reply to: 17894
Sound of line level filters
fiogf49gjkf0d
I thought that a digital crossover had a negative impact on sound quality -- especially for use between a midbass, midrange and tweeter channels. So I made an experiment a what I learned was not expected.
I used my mid horn and two high pass filters in front of my Rowland amp for a shootout -- one digital DBX Driverack, another line level passive RC. Simple 6 db/octave at 200hz high pass. Listened to different records...
The digital filter had an obvious advantage in the attack and dynamics, but suffered from dry decays, lack of delicacy, and transparency. The passive filter was much more natural, transparent, with sophistication and nuance but suffered significantly, LACKING attack and dynamics. So both filters are incompetent in my opinion, in own ways. Are there other filters that get both the attack and decay right? Maybe passive RL or active line level like the Marchand?
Anyone has good experience with 6db/octave high pass filters in front of amps?
Gera

03-02-2012 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,302
Joined on 05-28-2004

Post #: 2
Post ID: 17895
Reply to: 17894
From another planet?
fiogf49gjkf0d
Gera, are you catapulted from another planet? Are you sure that you want to drive a mid horn with Rowland amp? What kind 6dB high-pass filter used RC network? Why digital filter had an obvious advantage in the attack and dynamics? What does it mean “suffered from dry decays”? What does it mean advantage or disadvantage in attack? What drives the passive filter? Anyhow, what you say has absolutely no sense. Not that I agree or disagree with your finding but even your description of what you do is absolutely strange.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
03-02-2012 Post does not mapped to Knowledge Tree
noviygera


Chicago, IL
Posts 129
Joined on 06-12-2009

Post #: 3
Post ID: 17896
Reply to: 17895
More sense
fiogf49gjkf0d
>>Gera, are you catapulted from another planet? Are you sure that you want to drive a mid horn with Rowland amp?

Romy, some people that know me will say "yes", I am not sure... Of course no, not the Rowland to drive my horns, this is the amp I have to begin basic tuning of my system, or more precisely tuning away from my current setup that uses the digital crossover to reach my goal in sound. I must start somewhere, so the first thing I want to do is to replace the digital crossover I am now using to high pass my midrange horn. I tried to use a capacitor as the high pass filter and it worked, I now have a high pass filter in front of the amp. This line level capacitor filter sounds good and bad at the same time. It somehow ate the "attack" of all music and what I am hearing is a more soft, polite and refined version of the sound I got with the digital filter. It is soft in a bad way, not good way, like water in front of the speaker that soaks up the energy of the sound.

I use a normal solid state pre amp to drive the amp, and I kept everything constant in this test -- only changing between filters. So the digital filter is not great -- it is rough sound like an mp3 compression but unlike the passive filter it does not dampen the initial energy in any sounds. What I would like to figure out is another high pass filter between the pre amp and amp. I remember you mentioned having experience with the Marchand crossover and also with using RL passive filter. What were your findings?
03-02-2012 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,302
Joined on 05-28-2004

Post #: 4
Post ID: 17899
Reply to: 17896
Impossible.
fiogf49gjkf0d
Nope, sorry, it does not make any sense for me. The use of Rowland amp I guess is fine if it being use for testing of the filters. Still if you use high-pass for your midrange horn then what resistor does in your RC filter? A first order filter, regardless of topology and type, shall not introduce any "attack" changes and shall not change any “damping” or “softness” of sound. Similar to it: the digital filter shall not introduce any digital MP3-like compression. Something that you’re doing is very wrong or the way how you perceive the results is very wrong. Run RTA sweeps and make sure that you digital and analog filters introduce the identical slopes and identical insertion loss if you have any. If your digital filter has digital compression and if your analog filter changes sound in band-pass so much then something is very wrong in your entire experiment.
 


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
03-07-2012 Post does not mapped to Knowledge Tree
noviygera


Chicago, IL
Posts 129
Joined on 06-12-2009

Post #: 5
Post ID: 17916
Reply to: 17899
Polarity
fiogf49gjkf0d
I think I figured it out. Capacitor polarity. I reversed the polarity (leads are black and red) and sound changed. Now it sounds closer to what I am looking for, with better transients. Not as good as the digital crossover in the transient department, but pretty good, maybe break in will help and I will also try Wima fkp2 and old POI caps instead of the KimberCap. Can report my findings if anyone interested.
Gera
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