In previous post, I was just speaking of a friend who doesn't has to retest "A" because "B" is so much better than anything before... That's exactly what I now feel about the new steeper crossover I have set up between my SVS subwoofers and Acoustat 2+2 electrostatic panels.
This is the biggest improvements I've made in years, vastly exceeding such things as wire changes, DAC changes, amplifier changes, and individual EQ changes, and even the vast improvements I made from Time Alignment using ARTA last month.
Changing from the 1+1 speakers to the 2+2 speakers would not have been as big, except in combination with the actual fact that I had never adjusted the treble on the 1+1's properly, so that was also an equivalent upgrade.
Seeing the many issues on both sides in the 100-200 Hz region, I was thinking steeper crossover was what I needed. I had tried setting the crossover frequency from 100 Hz up to 140 Hz, which had eliminated the suckout around 106 Hz called by front wall reflection cancellation. That had merely exchanged one problem for another, a depression from 160 Hz to 190 Hz caused by rolloff in the subwoofer. THAT depression was just about as bad sounding as the suckout.
I could not move the crossover frequency downwards without the 106 Hz suckout reappearing.
So, on to steeper crossover, which the plain vanilla miniDSP plug-ins let me do easily (I could not do this with my Behringer 2496 DEQ's, and though the DCX's I used to use could do it, I never tried, and I haven't used DCX's in ages because they don't have digital outputs).
I started at 130 Hz with a 48dB/octave Linkwitz Riley crossover alignment (or LR8, as it is abbreviated, because 8 poles). My previous crossover had been 24dB/octave, LR4.
I then tried 120 Hz, which was better on top but worse on bottom.
125 Hz seemed to split the difference perfectly, resulting in relatively flat response (flatter than ever before) from 20 Hz to 200 Hz, shown on 6th octave RTA 16k bins.
Upon listening, jaw dropped.
The front center of the image, which always seemed a bit iffy, was more solid than ever. Far more solid, and with more easily front to back. The entire image left to right is more solid with front-to-back depth. The bass is far more solid. There's no sound of strain--in fact, I can crank up 6dB louder than before without sense of strain. A terrible resonance I believed I was going to have to tear down one speaker to fix, has just disappeared, at higher levels.
This is just so much better. It's huge.
I never tried this before because of concern about the added phase shift. Linkwitz himself generally stuck with the LR4 because of reduced phase shift. And he therefore chose wide bandwidth drivers, and built his speakers around the requirements of the LR4 crossover.
I don't have that option with electrostats. They have given me a situation for which, in many cases, I NEED the steeper crossover for my system to work well.
I think now the front wall cancellation reflection needs to be removed either by crossing over to another speaker before it occurs (and with a steep crossover), or by moving the speakers way way far back from the front, as in fact my late friend Alan did with his Magnepans (which he said had been inspired by some guy in Japan).
Or perhaps it could be aligned with a room mode, which sort of seems to have been the case in the right channel. This is why I had ignored this problem so long...I did most of my subwoofer EQ testing on the Right Channel. And I had been somewhat obsessed by cancellation above 200 Hz. But I now know the 220 Hz suckout was the second-order cancellation. The fundamental was the 106 Hz suckout which was only clear in the left channel, where it was devistating to bass solidity, and image solidity generally, as bass would always shift right to where there was no suckout (in fact, uncorrected, a big peak) because of the room mode.
But I have very little wiggle room in the placement of my speakers, giving my living room is also a functioning part of the house. I'd already moved my electrostatic speakers further and further out from the wall, over years, as it was clear it was important to improving the sound. The point I reached here seemed now seemed to be about as good as it got, and needed to be. But remember I did this testing, in particular, on the right channel because the left channel is so tightly constrained by other furniture it's hard to move. I assumed similarity in the wall distance thing, it turns out, which wasn't so similar.
Since the speakers are already as far out as they can be, I have to make the best of it, but the current distance (45 inches to center of speaker) turns out to work remakably well, fantastically well, with a 125 Hz LR8 crossover.
At some point, I can push it further, and turn the LR8 into a digitally corrected phase linear LR8. Linkwitz himself didn't much do the linear phase thing, he suggested issues with it, which he even described to me in person, and still on his website.
I intend to give the linear phase crossover thing a good staging, but I want to take awhile to get the immense advantages of the regular LR8 to sink in, and perhaps make some other adjustments first, including to the supertweeter crossovers.
(Tested music included: Supertramp Crime of the Century, which presented some other issues, to be discussed in future posts.)
This is the biggest improvements I've made in years, vastly exceeding such things as wire changes, DAC changes, amplifier changes, and individual EQ changes, and even the vast improvements I made from Time Alignment using ARTA last month.
Changing from the 1+1 speakers to the 2+2 speakers would not have been as big, except in combination with the actual fact that I had never adjusted the treble on the 1+1's properly, so that was also an equivalent upgrade.
Seeing the many issues on both sides in the 100-200 Hz region, I was thinking steeper crossover was what I needed. I had tried setting the crossover frequency from 100 Hz up to 140 Hz, which had eliminated the suckout around 106 Hz called by front wall reflection cancellation. That had merely exchanged one problem for another, a depression from 160 Hz to 190 Hz caused by rolloff in the subwoofer. THAT depression was just about as bad sounding as the suckout.
I could not move the crossover frequency downwards without the 106 Hz suckout reappearing.
So, on to steeper crossover, which the plain vanilla miniDSP plug-ins let me do easily (I could not do this with my Behringer 2496 DEQ's, and though the DCX's I used to use could do it, I never tried, and I haven't used DCX's in ages because they don't have digital outputs).
I started at 130 Hz with a 48dB/octave Linkwitz Riley crossover alignment (or LR8, as it is abbreviated, because 8 poles). My previous crossover had been 24dB/octave, LR4.
I then tried 120 Hz, which was better on top but worse on bottom.
125 Hz seemed to split the difference perfectly, resulting in relatively flat response (flatter than ever before) from 20 Hz to 200 Hz, shown on 6th octave RTA 16k bins.
Upon listening, jaw dropped.
The front center of the image, which always seemed a bit iffy, was more solid than ever. Far more solid, and with more easily front to back. The entire image left to right is more solid with front-to-back depth. The bass is far more solid. There's no sound of strain--in fact, I can crank up 6dB louder than before without sense of strain. A terrible resonance I believed I was going to have to tear down one speaker to fix, has just disappeared, at higher levels.
This is just so much better. It's huge.
I never tried this before because of concern about the added phase shift. Linkwitz himself generally stuck with the LR4 because of reduced phase shift. And he therefore chose wide bandwidth drivers, and built his speakers around the requirements of the LR4 crossover.
I don't have that option with electrostats. They have given me a situation for which, in many cases, I NEED the steeper crossover for my system to work well.
I think now the front wall cancellation reflection needs to be removed either by crossing over to another speaker before it occurs (and with a steep crossover), or by moving the speakers way way far back from the front, as in fact my late friend Alan did with his Magnepans (which he said had been inspired by some guy in Japan).
Or perhaps it could be aligned with a room mode, which sort of seems to have been the case in the right channel. This is why I had ignored this problem so long...I did most of my subwoofer EQ testing on the Right Channel. And I had been somewhat obsessed by cancellation above 200 Hz. But I now know the 220 Hz suckout was the second-order cancellation. The fundamental was the 106 Hz suckout which was only clear in the left channel, where it was devistating to bass solidity, and image solidity generally, as bass would always shift right to where there was no suckout (in fact, uncorrected, a big peak) because of the room mode.
But I have very little wiggle room in the placement of my speakers, giving my living room is also a functioning part of the house. I'd already moved my electrostatic speakers further and further out from the wall, over years, as it was clear it was important to improving the sound. The point I reached here seemed now seemed to be about as good as it got, and needed to be. But remember I did this testing, in particular, on the right channel because the left channel is so tightly constrained by other furniture it's hard to move. I assumed similarity in the wall distance thing, it turns out, which wasn't so similar.
Since the speakers are already as far out as they can be, I have to make the best of it, but the current distance (45 inches to center of speaker) turns out to work remakably well, fantastically well, with a 125 Hz LR8 crossover.
At some point, I can push it further, and turn the LR8 into a digitally corrected phase linear LR8. Linkwitz himself didn't much do the linear phase thing, he suggested issues with it, which he even described to me in person, and still on his website.
I intend to give the linear phase crossover thing a good staging, but I want to take awhile to get the immense advantages of the regular LR8 to sink in, and perhaps make some other adjustments first, including to the supertweeter crossovers.
(Tested music included: Supertramp Crime of the Century, which presented some other issues, to be discussed in future posts.)
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