Hello fellow forum members.
Everyone loves a good subwoofer thread.
Before I get into the Pure Low GR, a little on my subwoofer history. Back in the 90's I auditioned several subs from various brands like Velodyne and Martin Logan and B&W etc. The listening sessions at the dealers never seemed to pull it off. The sub always seemed intrusive and boomy. Interesting point that I automatically said the singular "sub" as I don't recally anyone doing stereo subwoofers back then. Mayber some of you experienced this but I don't think it was a thing back then. Well, eventually in the early 2000's I pulled the trigger and bought a B&W 800 ASW subwoofer and played with that for a while. it was a sealed sub which was a plus but it didn't even have variable phase. (What was I thinking. Man I was so dumb) Getting it to integrate for music never happened. Not for lack of effort, I just did not have the skill and the subwoofer didn't have the needed controls. So, I never used it for music and only turned it on for movies.
Fast forward about 10 years and subwoofers became an obsession. There had been a lot of "research" on subwoofers for me to sink my teeth into. There was the famous paper by Todd Welti and the work by Earl Geddes. And, REW had been invented so taking acoustic measurements became easy. The ideas of distributed bass array (DBA) intrigued me. So, I purchased a pair of Funk 18.0's and a pair of Rythmik F18's and went to work. I used REW and 100's of measurements to get them sounding what I thought was good. At one point I ran across the MSO (Multi-Sub-Optimizer) program. This was really cool as you simply measure each subwoofer and enter the parameters you want to meet and it goes to work iterating on the Gain, Delay, and PEQ's to give the needed settings for extremely flat frequency response. I used the DBA method along with MSO to integrate a few systems with JL Audio subs. Each time I was able to get ruler flat bass from whatever the crossover point was down to 20Hz.
During this time I also experimented some with smaller subs (8" or 10" woofers) mostly from REL. My conclusions from this is maybe that is fine if one is extending the bass of a 2-way speaker but this is never going to work along side a world class contender. e.g. Magico, Rockport, Wilson, Stenheim, Goebel, etc. The idea of a DBA with 4 small subs with 8" woofers to pair with large speakers is not viable IMO.
From this work I learned a lot about integrating subwoofers. (Mostly what not to do) I learned that 4 subwoofers are definitely not needed. I learned that 3 subwoofers are not needed either. A stero pair of subwoofer is sufficient to achieve great results. In fact a stereo pair is both necessary and sufficient. I also experienced the "space" thing that subwoofers do. To me, this s a much bigger deal than the low end "thump" that subs bring. Even non-audiophiles could easily identify this. For example, there was one time when a non-audiophile came over. I could easily turn the subs on and off with the push of a button without interrupting the music in any way. After a few times he held his arms out, pointed at the main speakers and said "without subs" . He then widened his arms to way outside the speakers and said "with subs". There were several audiophilles who came to my room and commented that this was the first time they could not tell subs were on until I turned them off. (This was with a stereo pair in the front of the room by the main speakers).
OK, so what is the problem? To me the bass sounded thick and slow. Sure there was more bass and there was the soundstage "space" thing which was nice. But the bass lacked texture and articulation. On everything but EDM I enjoyed the music more without the subs. I believe the biggest issue here is that at least 95% of subwoofers on the market are built for home theater. They have woofers that are heavy with thick rubber surrounds. If I want articulation and texture along with the low end grunt then it is clear that the woofer needs to be nimble. With this condition the field of available subwoofers is very narrow. I purchased a pair of the Wilson Benesch Torus subs. These were a substantial improvement over the others. They are passive so I used my trusty pair of Jeff Rowland Model 6's along with the Wilson ActivXo to run them. Now I had subs that could produce space, low end grunt, texture and articulation. Sure they still have some issues but overall pretty nice. I was able to integrate these with the Avantgarde Trio Spacehorns pretty easily without any DSP. Although I thought the soun was still a little blurry with the Torus, most who listened to the Trio system preferred the sound with the Torus engaged. They added foundation and space to the sound.
Finally, we have arrived. Last week I took delivery on a pair of Pure Low GR infrasonic panels. They are about 4 feet wide and 3 feet tall and 6 inches thick. They are a panel but they only radiate sound forward (not a dipole). They have bass extension flat to 10 Hz and can move serious amounts of air if needed. But the most important part is the "quickness" of response. The panel is so light weight. It was originally designed to pair with the Qual ESL. So matching it up to any speaker is not going to be an issue.
I put them in roughly the same place I had the Torus. i was not very careful with positioning at all. Just roughly in place. I even left the same crossover setting the Torus had. So yesterday I finally had some time to give them a listen. Wow! what these things do is incredible. After playing a few tracks at relatively low levels to make sure everything was alright I started down a path of tracks with lower bass. I honestly wasn't expecting much and really thought the sound would be horrible as I had not spent any time on integration. This was really an excerise in making sure everything worked. But to my surprise things sounded really, really nice. I sat there thinking how can they sound this good without even trying? One of things right of was more than just space (as in soundstage width etc) was that there was 3 dimensional body to the sound. I can't wait to spend a few hours getting them really dialed in and coherent with the spacehorns.
I want to share this to illustrate how different these are. I'm sure most have experienced tweeter hiss. You know, in some systems you go over to the speaker and put your ear next to the tweeter and you can hear noise. Well, when I was listening last night (without music playing) I was hearing this kind of tweeter hiss, but the sound was not coming from the Trios. It was coming from the panels. My old Jeff Rowland amps are too noisy. I never heard this from the Torus or any other subwoofer for that matter. The driver in those is far to heavy to reproduce this type of sound. I will need a better amplifier for them.
I will share more as the integration moves along.
Everyone loves a good subwoofer thread.
Before I get into the Pure Low GR, a little on my subwoofer history. Back in the 90's I auditioned several subs from various brands like Velodyne and Martin Logan and B&W etc. The listening sessions at the dealers never seemed to pull it off. The sub always seemed intrusive and boomy. Interesting point that I automatically said the singular "sub" as I don't recally anyone doing stereo subwoofers back then. Mayber some of you experienced this but I don't think it was a thing back then. Well, eventually in the early 2000's I pulled the trigger and bought a B&W 800 ASW subwoofer and played with that for a while. it was a sealed sub which was a plus but it didn't even have variable phase. (What was I thinking. Man I was so dumb) Getting it to integrate for music never happened. Not for lack of effort, I just did not have the skill and the subwoofer didn't have the needed controls. So, I never used it for music and only turned it on for movies.
Fast forward about 10 years and subwoofers became an obsession. There had been a lot of "research" on subwoofers for me to sink my teeth into. There was the famous paper by Todd Welti and the work by Earl Geddes. And, REW had been invented so taking acoustic measurements became easy. The ideas of distributed bass array (DBA) intrigued me. So, I purchased a pair of Funk 18.0's and a pair of Rythmik F18's and went to work. I used REW and 100's of measurements to get them sounding what I thought was good. At one point I ran across the MSO (Multi-Sub-Optimizer) program. This was really cool as you simply measure each subwoofer and enter the parameters you want to meet and it goes to work iterating on the Gain, Delay, and PEQ's to give the needed settings for extremely flat frequency response. I used the DBA method along with MSO to integrate a few systems with JL Audio subs. Each time I was able to get ruler flat bass from whatever the crossover point was down to 20Hz.
During this time I also experimented some with smaller subs (8" or 10" woofers) mostly from REL. My conclusions from this is maybe that is fine if one is extending the bass of a 2-way speaker but this is never going to work along side a world class contender. e.g. Magico, Rockport, Wilson, Stenheim, Goebel, etc. The idea of a DBA with 4 small subs with 8" woofers to pair with large speakers is not viable IMO.
From this work I learned a lot about integrating subwoofers. (Mostly what not to do) I learned that 4 subwoofers are definitely not needed. I learned that 3 subwoofers are not needed either. A stero pair of subwoofer is sufficient to achieve great results. In fact a stereo pair is both necessary and sufficient. I also experienced the "space" thing that subwoofers do. To me, this s a much bigger deal than the low end "thump" that subs bring. Even non-audiophiles could easily identify this. For example, there was one time when a non-audiophile came over. I could easily turn the subs on and off with the push of a button without interrupting the music in any way. After a few times he held his arms out, pointed at the main speakers and said "without subs" . He then widened his arms to way outside the speakers and said "with subs". There were several audiophilles who came to my room and commented that this was the first time they could not tell subs were on until I turned them off. (This was with a stereo pair in the front of the room by the main speakers).
OK, so what is the problem? To me the bass sounded thick and slow. Sure there was more bass and there was the soundstage "space" thing which was nice. But the bass lacked texture and articulation. On everything but EDM I enjoyed the music more without the subs. I believe the biggest issue here is that at least 95% of subwoofers on the market are built for home theater. They have woofers that are heavy with thick rubber surrounds. If I want articulation and texture along with the low end grunt then it is clear that the woofer needs to be nimble. With this condition the field of available subwoofers is very narrow. I purchased a pair of the Wilson Benesch Torus subs. These were a substantial improvement over the others. They are passive so I used my trusty pair of Jeff Rowland Model 6's along with the Wilson ActivXo to run them. Now I had subs that could produce space, low end grunt, texture and articulation. Sure they still have some issues but overall pretty nice. I was able to integrate these with the Avantgarde Trio Spacehorns pretty easily without any DSP. Although I thought the soun was still a little blurry with the Torus, most who listened to the Trio system preferred the sound with the Torus engaged. They added foundation and space to the sound.
Finally, we have arrived. Last week I took delivery on a pair of Pure Low GR infrasonic panels. They are about 4 feet wide and 3 feet tall and 6 inches thick. They are a panel but they only radiate sound forward (not a dipole). They have bass extension flat to 10 Hz and can move serious amounts of air if needed. But the most important part is the "quickness" of response. The panel is so light weight. It was originally designed to pair with the Qual ESL. So matching it up to any speaker is not going to be an issue.
I put them in roughly the same place I had the Torus. i was not very careful with positioning at all. Just roughly in place. I even left the same crossover setting the Torus had. So yesterday I finally had some time to give them a listen. Wow! what these things do is incredible. After playing a few tracks at relatively low levels to make sure everything was alright I started down a path of tracks with lower bass. I honestly wasn't expecting much and really thought the sound would be horrible as I had not spent any time on integration. This was really an excerise in making sure everything worked. But to my surprise things sounded really, really nice. I sat there thinking how can they sound this good without even trying? One of things right of was more than just space (as in soundstage width etc) was that there was 3 dimensional body to the sound. I can't wait to spend a few hours getting them really dialed in and coherent with the spacehorns.
I want to share this to illustrate how different these are. I'm sure most have experienced tweeter hiss. You know, in some systems you go over to the speaker and put your ear next to the tweeter and you can hear noise. Well, when I was listening last night (without music playing) I was hearing this kind of tweeter hiss, but the sound was not coming from the Trios. It was coming from the panels. My old Jeff Rowland amps are too noisy. I never heard this from the Torus or any other subwoofer for that matter. The driver in those is far to heavy to reproduce this type of sound. I will need a better amplifier for them.
I will share more as the integration moves along.
