Pure Low GR -- Infrasonic Panel

[LL21]

Thanks for continuing to update! To be fair given that this is work in progress, that plot looks very smooth! Many people would be very happy to leave it right there! 4db down sub 30hz is pretty good. We start to drop 4db starting at 25hz.

 

[sbnx]

Hi Todd,

Thank you for taking us on your journey with the Pure Low!

How would you describe the difference in oomph and sense of physical impact between the Torus and the Pure Low?

Okay, it is finally time to answer Ron's question.

I finished integrating both Pure Low at 30Hz this weekend. I say finished but in reality it does need a touch more height. I am currently using pieces of MDF to give them some height. I want to get some spike feet that are more adjustable. I think (know) that this is going to be much more critical when integrating them with the Trio at 125Hz.

In regard to oomph and physical impact of the Pure Low, I have not experienced anything that does what these do. The question I most often get is "Can they pressureize a room?". I think this is because people are skeptical that a panel can effectively pressurize. The Pure Low's get a 10 out of 10 in this regard. For physical impact I also give them a 10 out of 10. I will offer two songs as an example.

The first is Lydia Ainsworth's "Afterglow". I use this track all the time with subwoofers as it is very telling of how much sub 30Hz energy there is in the room. In the opening seconds you can hear and feel the low bass energy. It is very enveloping. There are several very low (20-30Hz) sustains that push. This song is full of this type of thing. By push I mean the bass energy physically pushes on me. The amount of "push" generated by the Pure Low is amazing. The Torus is a great subwoofer but it did not generate nearly this much envelopment and push.

The second is "Poem of Chinese Drum". I think most people have heard at least part of this one. The opening drum beats are very visceral. Ron experienced this when he heard my system. When setup properly the drum has a deep boom with a very quick and clear transient attack. This will punch the listener in the chest. This is just with the Spacehorns and is expected as the spacehorn plays flat down to 35Hz and the Drum is pitched at 40Hz. What the Pure Low's bring to the party is fullness to the drum. Now with each drum strike I can hear the full space of the drum. There is a foundational depth to the note that was not there with the spacehorn and was only hinted at with the Torus. It is like the energy of the drum goes through the drum and expands into the space. The experience is much more than visceral with the Pure Low. I had no idea that all of this was there before.

Ron often talks of the "acoustic center". He relates this to the point at which half the energy is above and half the energy is below. I think the idea is to relate this to how much "body" the music has. If the center is too high, the music sounds unrealistic because it is all about the upper midrange and treble. Inserting the Pure Low's definitely pulls the "acoustic center" downward. They have grounded the music. Whether I listen to vocalists or oboe the sound is much richer; much more full, much denser. The Torus did a decent job here, but just not to the same level. Actually, not really close. I have heard many people who kinda dismiss the bottom 2 octaves. Wait, how could they dismiss the bottom 2 octaves because doesn't that go up to 80Hz? No, I consider the first octave to be between 10 and 20Hz and the second octave to be between 20 and 40Hz. The argument is usally something like "Well, there just isn't much music below 40Hz". There is actually a great deal of content below 40Hz and even below 20Hz. I think people just have not experienced this in a convencing way.

What makes the Pure Low spectacular is that it gives all of the oomph, physical impact, envelopment, depth, richness and fullness without being bloated. Upright bass is still articulate. Timpani are still quick and clear. The Torus was able to do the same things but to much less extent. In thinking about the Funk vs. the Torus vs. the Pure Low. The Funk did a better job than the Torus on envelopment and oomph but it would just be in the way higher up. The Torus got out of the way more compared to the Funk and did provide some foundation and envelopment. The Pure Low gets out of the way and gives all of the fun subwoofer stuff in spades.

It is interesting that comparing the measurements of the Torus and the Pure Low the frequency response is ostensibly the same for both. Yet, the differences are stark in terms of sound quality.

 

[jbrrp1]

Okay, it is finally time to answer Ron's question.

I finished integrating both Pure Low at 30Hz this weekend. I say finished but in reality it does need a touch more height. I am currently using pieces of MDF to give them some height. I want to get some spike feet that are more adjustable. I think (know) that this is going to be much more critical when integrating them with the Trio at 125Hz.

In regard to oomph and physical impact of the Pure Low, I have not experienced anything that does what these do. The question I most often get is "Can they pressureize a room?". I think this is because people are skeptical that a panel can effectively pressurize. The Pure Low's get a 10 out of 10 in this regard. For physical impact I also give them a 10 out of 10. I will offer two songs as an example.

The first is Lydia Ainsworth's "Afterglow". I use this track all the time with subwoofers as it is very telling of how much sub 30Hz energy there is in the room. In the opening seconds you can hear and feel the low bass energy. It is very enveloping. There are several very low (20-30Hz) sustains that push. This song is full of this type of thing. By push I mean the bass energy physically pushes on me. The amount of "push" generated by the Pure Low is amazing. The Torus is a great subwoofer but it did not generate nearly this much envelopment and push.

The second is "Poem of Chinese Drum". I think most people have heard at least part of this one. The opening drum beats are very visceral. Ron experienced this when he heard my system. When setup properly the drum has a deep boom with a very quick and clear transient attack. This will punch the listener in the chest. This is just with the Spacehorns and is expected as the spacehorn plays flat down to 35Hz and the Drum is pitched at 40Hz. What the Pure Low's bring to the party is fullness to the drum. Now with each drum strike I can hear the full space of the drum. There is a foundational depth to the note that was not there with the spacehorn and was only hinted at with the Torus. It is like the energy of the drum goes through the drum and expands into the space. The experience is much more than visceral with the Pure Low. I had no idea that all of this was there before.

Ron often talks of the "acoustic center". He relates this to the point at which half the energy is above and half the energy is below. I think the idea is to relate this to how much "body" the music has. If the center is too high, the music sounds unrealistic because it is all about the upper midrange and treble. Inserting the Pure Low's definitely pulls the "acoustic center" downward. They have grounded the music. Whether I listen to vocalists or oboe the sound is much richer; much more full, much denser. The Torus did a decent job here, but just not to the same level. Actually, not really close. I have heard many people who kinda dismiss the bottom 2 octaves. Wait, how could they dismiss the bottom 2 octaves because doesn't that go up to 80Hz? No, I consider the first octave to be between 10 and 20Hz and the second octave to be between 20 and 40Hz. The argument is usally something like "Well, there just isn't much music below 40Hz". There is actually a great deal of content below 40Hz and even below 20Hz. I think people just have not experienced this in a convencing way.

What makes the Pure Low spectacular is that it gives all of the oomph, physical impact, envelopment, depth, richness and fullness without being bloated. Upright bass is still articulate. Timpani are still quick and clear. The Torus was able to do the same things but to much less extent. In thinking about the Funk vs. the Torus vs. the Pure Low. The Funk did a better job than the Torus on envelopment and oomph but it would just be in the way higher up. The Torus got out of the way more compared to the Funk and did provide some foundation and envelopment. The Pure Low gets out of the way and gives all of the fun subwoofer stuff in spades.

It is interesting that comparing the measurements of the Torus and the Pure Low the frequency response is ostensibly the same for both. Yet, the differences are stark in terms of sound quality.

@sbnx I am following your journey with these avidly, as these are very interesting subs. I'm curious about the room placement that you are using to bring this impactful presentation: how close to the back wall and side walls? How much elevation off of the floor?

 

[Ron Resnick]

Okay, it is finally time to answer Ron's question.

I finished integrating both Pure Low at 30Hz this weekend. I say finished but in reality it does need a touch more height. I am currently using pieces of MDF to give them some height. I want to get some spike feet that are more adjustable. I think (know) that this is going to be much more critical when integrating them with the Trio at 125Hz.

In regard to oomph and physical impact of the Pure Low, I have not experienced anything that does what these do. The question I most often get is "Can they pressureize a room?". I think this is because people are skeptical that a panel can effectively pressurize. The Pure Low's get a 10 out of 10 in this regard. For physical impact I also give them a 10 out of 10. I will offer two songs as an example.

The first is Lydia Ainsworth's "Afterglow". I use this track all the time with subwoofers as it is very telling of how much sub 30Hz energy there is in the room. In the opening seconds you can hear and feel the low bass energy. It is very enveloping. There are several very low (20-30Hz) sustains that push. This song is full of this type of thing. By push I mean the bass energy physically pushes on me. The amount of "push" generated by the Pure Low is amazing. The Torus is a great subwoofer but it did not generate nearly this much envelopment and push.

The second is "Poem of Chinese Drum". I think most people have heard at least part of this one. The opening drum beats are very visceral. Ron experienced this when he heard my system. When setup properly the drum has a deep boom with a very quick and clear transient attack. This will punch the listener in the chest. This is just with the Spacehorns and is expected as the spacehorn plays flat down to 35Hz and the Drum is pitched at 40Hz. What the Pure Low's bring to the party is fullness to the drum. Now with each drum strike I can hear the full space of the drum. There is a foundational depth to the note that was not there with the spacehorn and was only hinted at with the Torus. It is like the energy of the drum goes through the drum and expands into the space. The experience is much more than visceral with the Pure Low. I had no idea that all of this was there before.

Ron often talks of the "acoustic center". He relates this to the point at which half the energy is above and half the energy is below. I think the idea is to relate this to how much "body" the music has. If the center is too high, the music sounds unrealistic because it is all about the upper midrange and treble. Inserting the Pure Low's definitely pulls the "acoustic center" downward. They have grounded the music. Whether I listen to vocalists or oboe the sound is much richer; much more full, much denser. The Torus did a decent job here, but just not to the same level. Actually, not really close. I have heard many people who kinda dismiss the bottom 2 octaves. Wait, how could they dismiss the bottom 2 octaves because doesn't that go up to 80Hz? No, I consider the first octave to be between 10 and 20Hz and the second octave to be between 20 and 40Hz. The argument is usally something like "Well, there just isn't much music below 40Hz". There is actually a great deal of content below 40Hz and even below 20Hz. I think people just have not experienced this in a convencing way.

What makes the Pure Low spectacular is that it gives all of the oomph, physical impact, envelopment, depth, richness and fullness without being bloated. Upright bass is still articulate. Timpani are still quick and clear. The Torus was able to do the same things but to much less extent. In thinking about the Funk vs. the Torus vs. the Pure Low. The Funk did a better job than the Torus on envelopment and oomph but it would just be in the way higher up. The Torus got out of the way more compared to the Funk and did provide some foundation and envelopment. The Pure Low gets out of the way and gives all of the fun subwoofer stuff in spades.

It is interesting that comparing the measurements of the Torus and the Pure Low the frequency response is ostensibly the same for both. Yet, the differences are stark in terms of sound quality.

Very, very interesting, Todd! Thank you for this very specific and detailed and insightful review!

The Pure Low seems to be a perfect solution for its mission!

Merry Christmas to you and Sally and the kids!

 

[sbnx]

@sbnx I am following your journey with these avidly, as these are very interesting subs. I'm curious about the room placement that you are using to bring this impactful presentation: how close to the back wall and side walls? How much elevation off of the floor?

Hello @jbrrp1 ,

Regarding height. I believe that all subwoofers need much more height from the floor to sound their best. This has been the case with every subwoofer I have owned or setup. (And that is a sizable list) I currently have three pieces of MDF under each foot. One piece of 3/4", one piece of 1/2" and one pice of 1/4" so about 1.5" of added height in addition to the foot that comes on them. I have them raked back about 0.12 degrees.

I have the Pure Low is: About 22" from the side wall to the left inside corner. About 55" from the front wall to the right corner. I specify right/left as the Pure Low is wide and I have it toe-ed in to match the main speakers.

My main speakers are pulled out about 13.5' from the front wall so I have plenty of room behind them to play with. I am using the WIlson Active XO crossover. It only has an option of 12 or 18 dB/Oct crossover slope and it does not have EQ capability. So I used the position of the Pure Low in the room to find the best falling response. If I used a DSP or had a higher crossover slope then it would open up more positioning latitude. The position in your room would be different.

Based on Patrick's inputs, I believe Roy Gregory will be writing a review soon on the Pure Low GR. I know he positions them close to the wall. You can see them in many of the potos of the reviews he does. I also beleive that he will comment on the possiblities of putting them along the side wall which, IMHO, would work as long as the crossover poinnt is low (say less then 35Hz.)

~Todd