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My high pass filter experiment and a couple of questions

Prior to this "experiment" I was running my Maranztz SA10 with balanced Kimber Silver Streak to my Cary SLP05 and from there I was using balanced Kimber Silver Streak to my Cary V12; from my SLP05 I was going out of the RCA outs with some old Monster Cable to my ancient M&K MX-100.

Back in ’95 I bought a M&K LP-15 passive high pass filter and I liked it with the gear I was then using, but as the gear got bigger and better and I also started using balanced interconnects I quit using it.

A few days ago I dug it out and I left the balanced connections from CDP to the pre the same, but from the pre I went with some Kimber PBJ RCA (because I don’t have any Silver Streak RCA that is long enough) from my pre into the high pass filter, and from the high pass I went with Kimber PBJ RCA to my amp; I hooked up the Monster Cable (that I had been going from the pre to the sub with) to the high pass filter and went to the sub with that.

Initially I kind of liked it, but tonight I wasn’t so sure. (It almost seems as if I am prone to INITIALLY like any change I make.)

I have a lot less gain and a lot more real extate available on the volume knob of my pre. That part I do like. I assume that is because I am going into my amp with RCA connection versus balanced and less voltage?

The high pass filter does have a treble control and a bass control. Initially I was reticent to use it any way except with both controls turned all the way to full. However, I did find that by playing with the treble control a smidge I could take the hard (bright) edge off of certain (not all) CDs. I left the bass control turned all the way to full because I am thinking it is supposed to do the same thing that the level control on the sub is doing, so why defeat that on the sub?

Another question is: since the LP-15 is theoretically supposed to roll the bass off at 85 Hz and the Revel M126Be’s I am now using are supposed to be trying to go down to 54 Hz, if those speakers are only being sent 85 Hz and above from the amp, this should make them an easier load to drive? I would think that their sensitivity doesn’t change, but now the impedance should not have to dip as low?

And still another question(?) does balanced from CPP to pre and RCA from pre to high pass and then to amp seem problematic? And I suppose I should consider upgrading the PBJ RCAs to Silver Streak RCAs?

 

 

 

 

immatthewj
mashif
254 posts
 

I've been engaged in that experiment for a few months now. I bought a balanced HPF from Marchand. It filters below 80hz and is very effective at creating space for the sub to fill. I was quite pleased with the low end. 

However, I had issues in other areas that I couldn't solve with room treatments so I just purchased a high quality graphic eq. I decided to use that below 80 as well, and was able to dial it in nicely. So now, the sub is relegated to below 40 where my speakers fall off a cliff. 

If you're interested, I may sell the Marchand HPF. 

 

 

 

 

james633
1,036 posts
 

Honestly not sure I followed your setup wiring or know your equipment. But I have a few thoughts. 
 

#1 I love active crossovers and the ability to highpass. I would not run a system without one these days. If does not improve your system then the setup must not be quite right. 
 

#2 steep crossovers work better. 24db has always worked better for me than the 12 on the sub and 6 on the speakers. 
 

#3 you can mix and match rca and balanced without issue. Just have to make the gains. 
 

I have used a few crossovers in the past. I have heard no loss of detail or soundstage with JL audio or the sublime acoustics I use now. When using ones built into surround processors I feel I lose a bit of sound stage. 

immatthewj OP
2,034 posts
 

Honestly not sure I followed your setup wiring or know your equipment. But I have a few thoughts. 

@james633 , it is as follows;

CDP IN to preamp via balanced (Kimber Silver Streak) interconnects/preamp IN to passive high pass filter via Kimber PBJ RCA interconnects.

FROM the high pass filter (and this is all via RCAs) : the treble pair of RCAs IN to the amplifier RCA inputs/the bass pair of RCAs IN to the sub's RCA inputs.

A couple of things I am keeping in consideration:

I don't think that the M&K LP-15 passive high pass filter is very high quality (and it is passive)

I am running balance interconnect out of the CDP TO the HP filter and a lesser grade of RCAs OUT of the HP to the amp

and the subwoofer is about 30 years old.

phusis's avatar
phusis
1,208 posts
 

@erik_squires wrote:

A single capacitor can be an effective high pass filter.

I’ll be doing that, not in the bass but with the inclusion of a dedicated tweeter (JBL 2405 Alnico) over my main speakers within shortly. A simple 1. order slope crossed in passively at just over 11kHz to augment the EV DH1A’s through the upper octave.

@james633 wrote:

I love active crossovers and the ability to highpass. I would not run a system without one these days. If does not improve your system then the setup must not be quite right.

+1

steep crossovers work better. 24db has always worked better for me than the 12 on the sub and 6 on the speakers.

Steep slopes (36dB/octave actively) mostly work better for me as well.

@immatthewj wrote:

I don’t think that the M&K LP-15 passive high pass filter is very high quality (and it is passive)

Question is if you’re bottlenecking your HP-initiative to begin with. If you are able to identify some positives inserting a high-pass filter as is however, imagine what it could do even more dedicated - i.e.: via a better means of HP-filtration.

james633
1,036 posts
 

There are a number of digital active ones. Something like the mini dspSHD being one of the cheaper options.
 

If messing around on a computer turns you off a good and cheap analogue model from Sublime Acustics is the K231 ($600). They have a no question asked return policy. I find the model above it K235 (same thing with XLR) to be transparent and probably as good as more expensive options from JL Audio or Bryston (I have not heard the bryston so just a guess on that one).  
 

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