Pure Low GR -- Infrasonic Panel

[sbnx]

...the fact that they are panels made me think more about longevity/reliability than more traditional cone subs where I would imagine, if stuck, a great audiotech could fix them.

Hello Lloyd, I would like to address your concern about reliability/longevity of the Panel. I have been exchanging e-mails with Patrick (The owner of Pure Low) on several topics. One of which is reliability and repair. I am just going to paste his comments from the e-mails here. As you can see he is taking reliability very seriously and has an excellent track record.

"For power handling and reliability, I do tests before shipping the speakers, at all frequencies, from a few Hz up to 300 or 400 Hz and this is the thermal circuit breaker of the amplifier (600 watts /2.5 Ohms) which works. The Purelow does not heat up. The issue of reliability is of the utmost importance, as I cannot afford to sell a product that fails. This is the thing I work on the most, down to the smallest detail, imagining every possible breakdown. But no Purelow has ever broken down, with customers using them every day, without hesitation, since 2016. So it's been 8 years without any problem, and I was able to dismantle certain parts of the speakers, the most exposed, and check that they were like new. Furthermore, in the event of a problem, all parts are repairable."

"The Infraplanar N°1 still works perfectly, after 18 years of existence (2006). Since I have been working on this speaker, I have prioritized reliability, so that there are no breakdowns. There is also the question of power handling. It is impossible to burn it, with 42 meters of conductor in the open air. And since its frequency response is quite linear in the very low frequencies, it does not need additional power."

 

[LL21]

Hello Lloyd, I would like to address your concern about reliability/longevity of the Panel. I have been exchanging e-mails with Patrick (The owner of Pure Low) on several topics. One of which is reliability and repair. I am just going to paste his comments from the e-mails here. As you can see he is taking reliability very seriously and has an excellent track record.

"For power handling and reliability, I do tests before shipping the speakers, at all frequencies, from a few Hz up to 300 or 400 Hz and this is the thermal circuit breaker of the amplifier (600 watts /2.5 Ohms) which works. The Purelow does not heat up. The issue of reliability is of the utmost importance, as I cannot afford to sell a product that fails. This is the thing I work on the most, down to the smallest detail, imagining every possible breakdown. But no Purelow has ever broken down, with customers using them every day, without hesitation, since 2016. So it's been 8 years without any problem, and I was able to dismantle certain parts of the speakers, the most exposed, and check that they were like new. Furthermore, in the event of a problem, all parts are repairable."

"The Infraplanar N°1 still works perfectly, after 18 years of existence (2006). Since I have been working on this speaker, I have prioritized reliability, so that there are no breakdowns. There is also the question of power handling. It is impossible to burn it, with 42 meters of conductor in the open air. And since its frequency response is quite linear in the very low frequencies, it does not need additional power."

Hi Scott,

That is really appreciated. Thank you for taking the time to do that.

 

[sbnx]

A couple videos on subwoofer integration to follow.

 

[sbnx]

Integrating the Pure Low

 

[LL21]

Look forward to hearing how this sounds...you have taken a lot of time to post videos of certain recordings. You have the EDM one which is becoming very popular for people to listen to...Vini Vici...obviously with a lot of bass. Will be interesting to see how you find the PureLow fares on its own WITHOUT the dual bass horns of the AG.

 

[sbnx]

Update on the Pure Low. From my previous post you can see that last week I took some measurements and moved the position of it forward and sideways to find the spot that gave the best 20-30Hz response without any peaks higher up. I used the phase knob on the Wilson ActiveXo to get that close using REW measurements. I spent some time this weekend working to get them integrated with the spacehorns. The Pure Low is doing exactly what I expected it to do. I have never had a subwoofer with so little blur. It is extremely easy to hear what needs to happen to the sub so that it integrates with the spacehorns. By comparison the WB Torus was difficult. When integrating the Torus I could easily hear things that were not right but I was typically guessing at what to do to resolve the issue. I could eventually get there but it was a little harder. WIth the Pure Low I don't have to guess.

I still have a little more work to do. I integrated the left purelow with the left spacehorn and the right purelow with the right spacehorn. (Only one subwoofer can be integrated at a time.) Then I listened with everything on. It sounds already fantastic like this but it showed me that the right subwoofer is a little behind the left one. So I am going to need to bump the right one forward some more until they are both ingtegrated with each other and the right is integrated with its spacehorn. My guess is in the range of 1/4 inch.

Listening to Poem of Chinese Drum there is a weight and dimension to the drum that the Torus could not pull off. (Don't get me wrong, the Torus is a very nice subwoofer and is the best I had ever worked with but it is just not like the Pure Low.) By weight I don't mean just the "Thump" of the drum. but rather solidity.

I am looking forward to spending more time and aligning the left to right subs. This is going to bring way more punch since currently with them slightly misaligned it is causing a degree of smearing. But this is the interesting part. WIth the Torus this was just smearing or "thickening" of the bass note comeing from the durm. WIth the pure low the left to right misalignment is obvious. Easy to fix. Just need to do it.

Listening to the system I am not sure what a video is going to do here. Bass is already challenging to record on a mic and we are talking below 35 Hz bass in this case. I will try using a Shure microphone instead of the iphone mic. I am certain that you will have to listen with above average headphones to hear it. Earpods or similar things aren't going to work.

 

[LL21]

Update on the Pure Low. From my previous post you can see that last week I took some measurements and moved the position of it forward and sideways to find the spot that gave the best 20-30Hz response without any peaks higher up. I used the phase knob on the Wilson ActiveXo to get that close using REW measurements. I spent some time this weekend working to get them integrated with the spacehorns. The Pure Low is doing exactly what I expected it to do. I have never had a subwoofer with so little blur. It is extremely easy to hear what needs to happen to the sub so that it integrates with the spacehorns. By comparison the WB Torus was difficult. When integrating the Torus I could easily hear things that were not right but I was typically guessing at what to do to resolve the issue. I could eventually get there but it was a little harder. WIth the Pure Low I don't have to guess.

I still have a little more work to do. I integrated the left purelow with the left spacehorn and the right purelow with the right spacehorn. (Only one subwoofer can be integrated at a time.) Then I listened with everything on. It sounds already fantastic like this but it showed me that the right subwoofer is a little behind the left one. So I am going to need to bump the right one forward some more until they are both ingtegrated with each other and the right is integrated with its spacehorn. My guess is in the range of 1/4 inch.

Listening to Poem of Chinese Drum there is a weight and dimension to the drum that the Torus could not pull off. (Don't get me wrong, the Torus is a very nice subwoofer and is the best I had ever worked with but it is just not like the Pure Low.) By weight I don't mean just the "Thump" of the drum. but rather solidity.

I am looking forward to spending more time and aligning the left to right subs. This is going to bring way more punch since currently with them slightly misaligned it is causing a degree of smearing. But this is the interesting part. WIth the Torus this was just smearing or "thickening" of the bass note comeing from the durm. WIth the pure low the left to right misalignment is obvious. Easy to fix. Just need to do it.

Listening to the system I am not sure what a video is going to do here. Bass is already challenging to record on a mic and we are talking below 35 Hz bass in this case. I will try using a Shure microphone instead of the iphone mic. I am certain that you will have to listen with above average headphones to hear it. Earpods or similar things aren't going to work.

Hi Todd,

Thank you for not only take the time to be so detail oriented and methodical...but also documenting each move. Very educational.

Now here is the question (for me...and I suspect a few others)...do you anticipate moving the PureLows up to 100hz to see how well they stand in for the AG bass horns?

I know, I know, I know...by definition not the ideal set up. But many of us do not have the room for such a big undertaking...even the Purelow is difficult but at least it can go flat against the wall...and I am hoping it could actually go behind the main horns and be adjusted with the settings to work...so that overall, the footprint of the AG Trio G3 ends up something like 3-4 feet wide x 4 feet deep. By contrast, the side by side of the AG horns and AG basshorns eats up more like 4' x 5' and possibly more if they have to be away from the front wall.

 

[sbnx]

The Trio with Spacehorns do indeed represent a large footprint. We have asked Avantgarde to consider making a subwoofer system that would be smaller than the spacehorn. It could also be paired with other speakers. The idea is to take the cabinet of the Mezzo and use it as a sub. They are prioritizing other projects at the moment so no idea when or if this could become a reality.

Of course I am as curious as anyone whether the Pure Low will work with the Trios (sans Spacehorn). There is one guy who threw down the gauntlet and said he did not think it could work as well as the spacehorns. I am not one to shy away from a challenge. I have spoken to another person with Pure Lows and I know for a fact that it works just fine up into the 70-80Hz range. I have also spoken to Patrick about it and he has given some guidance on potential issues and where to look to resolve them. Here is my plan:

1. Integrate the Pure Lows with the spacehorns with a crossover point in the low 30's using the Wilson ActivXo. This allows me to work with the subs and get a handle on what they do in the really low range. So far (as my post above highlights) things are going extremely well with this. Shockingly good.
2. I need a better pair of amps. My Rowland Model 6's drive them without issue but they are quite old and showing signs of their age. Likely need to be recapped. I can hear noise from them. To that end I have ordered a pair of the Atma-sphere class D amplifiers to power them. I am expecting this 100W GaN FET based class D to be substantially quieter with more drive and authority than the Rowland. As a side note here, Patrick is working on an amplifier solution that can be sold witht he Pure Low.
3. I need a different crossover. The Wilson ActiveXo is certainly nice, but I want to try a DSP based crossover for several reasons. I don't really need it down at 30Hz but going up into the 120Hz range I think I am going to need finer resolution and more controls than the ActivXo has. I finally found one that I think will work. There are a lot of pro audio options available but to me these aren't going to work. (Of ourse they will do the DSP job. It is a matter of what other damage they do) I ordered one from Danville Signal. Hope to have it either late this week or early next week. What convinced me that it stands a chance is that the designer spent the first 20 years of his life as an analog designer. As a side note here. Patrick is working on two crossover solutions for the Pure Low. One analog and one DSP. TBD when the solutions will be ready.
4. I am going to need some feet that get it off the floor and allow me to adjust the height.
5. Once all of this is in place I will start working to integrate the Pure Low in the 120Hz range.

I am better than 50/50 that I can get it to work. It is certainly fast enough to integrate with the horns.

 

[LL21]

This is fantastic news, Todd. Thank you again. This is the professional time, commitment and care that goes a long way to people understanding more about the brand without having to wonder, or worse experiment themselves not knowing if it will all work (or if it can work, how it actually works without tons of random experiments).

Reading about your findings with Purelow and will be very very influential in how I think about AG Trio G3s.

(BTW, I do like what I read about the Mezzo G3 and have certainly been intrigued by the numerous videos people have made of them.)

 

[sbnx]

The Mezzo is a serious speaker. I think a lot of people may write it off because of the price. (Which is lower than its performance would suggest)

 

[Ron Resnick]

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?

 

[sbnx]

As I metioned, I have been communicating with Patrick about crossing over the Pure Lows at a much higher crossover point of 125Hz. He had never tried such a high crossover point and had some concerns. Patrick uses stacked Quad ESL57's and he had been experimenting using the Trinnov Amythest for the low pass crossover with good results. The Amythest is very powerful and has a lot of capability. Well, I guess curiosity got the better of him and he decided to see what would happen if he moved the crossover point up. So, he used the Amythest as a high pass filter on his mains at 120Hz and integrated the Pure Low below that. He said he played with several crossover types (Bessel, butterwork, LR) both 2nd and 4th order. He eventually settled on a 4th order Bessel. The quads are very demanding and will not tolerate interference from the subs. He indicated that the results were quite good and he was very satisfied with the result.

I think this is very encouraging. If he could get the Pure Low to work with Quads at 120Hz I am now convinced it is going to work with the Trios. One advantage the Trios have is that they have a natural low frequency cutoff in the 100Hz range so we don't have to use a high pass filter. I want to get in the new amplifiers and crossover before I start working on the higher crossover point. I know the Pure Low is going to sound different than the space horn. Different how? I don't know yet and will just have to see.

Patrick sent these pics to show how the Pure Low is positioned relative to the Quads.

 

[LL21]

As I metioned, I have been communicating with Patrick about crossing over the Pure Lows at a much higher crossover point of 125Hz. He had never tried such a high crossover point and had some concerns. Patrick uses stacked Quad ESL57's and he had been experimenting using the Trinnov Amythest for the low pass crossover with good results. The Amythest is very powerful and has a lot of capability. Well, I guess curiosity got the better of him and he decided to see what would happen if he moved the crossover point up. So, he used the Amythest as a high pass filter on his mains at 120Hz and integrated the Pure Low below that. He said he played with several crossover types (Bessel, butterwork, LR) both 2nd and 4th order. He eventually settled on a 4th order Bessel. The quads are very demanding and will not tolerate interference from the subs. He indicated that the results were quite good and he was very satisfied with the result.

I think this is very encouraging. If he could get the Pure Low to work with Quads at 120Hz I am now convinced it is going to work with the Trios. One advantage the Trios have is that they have a natural low frequency cutoff in the 100Hz range so we don't have to use a high pass filter. I want to get in the new amplifiers and crossover before I start working on the higher crossover point. I know the Pure Low is going to sound different than the space horn. Different how? I don't know yet and will just have to see.

Patrick sent these pics to show how the Pure Low is positioned relative to the Quads.

View attachment 140176
View attachment 140177

Thank you, Todd! That is super exciting news! Definitely look forward to hearing what you think. I presume that the controls over the Purelow panel enable you to adjust them to be placed behind speakers like your Trios or our XLFs? It appears that they are part behind the panels (as in literally behind) in the photos above you kindly posted.

 

[Kingrex]

I'm mad at you Todd. You got me all worked up. Then I find the price. Ouch. Seems like a fantastic sub. I'm gonna have to stick with making my own sub. Although I'm right there with the concept of an active crossover and a amp remote to the woofer enclosure. I have had a lot of people say to me the biggest drawback of one box subs is the plate amp and crossover are rattling in the enclosure. I may PM you one day over driver selection and cabinet configuration.
Keep posting on how they dial in and how the Atmasphere work with them.

 

[LL21]

The ultimate question Todd is whether you end up liking Purelow’s from 100hz down to around 30hz and adding back the Torus below 30hz. Or whether the Purelows deliver better results from 100hz down to 20hz and below on their own without the Torus.

 

[sbnx]

I'm mad at you Todd. You got me all worked up. Then I find the price. Ouch. Seems like a fantastic sub. I'm gonna have to stick with making my own sub. Although I'm right there with the concept of an active crossover and a amp remote to the woofer enclosure. I have had a lot of people say to me the biggest drawback of one box subs is the plate amp and crossover are rattling in the enclosure. I may PM you one day over driver selection and cabinet configuration.
Keep posting on how they dial in and how the Atmasphere work with them.

Hello Rex,

Sorry about that. The Pure Low is a different animal.

I am not a speaker designer. I would not speculate on which driver to use for a subwoofer. All I know is that for music I want a stiff, light weight driver that can move a large area of air. Not displacement of air as that starts to involve excursion and I don't need tons of excursion for music.

 

[sbnx]

The ultimate question Todd is whether you end up liking Purelow’s from 100hz down to around 30hz and adding back the Torus below 30hz. Or whether the Purelows deliver better results from 100hz down to 20hz and below on their own without the Torus.

The amps and crossover have shipped and I get them Monday/Tuesday of next week. I will likely use a good portion of the Thanksgiving holiday to work on them.

I will not need to add the Torus back in. The Pure Low plays down to 10Hz. So it will be Pure Low from 10Hz to 120Hz.

~Todd

 

[LL21]

The amps and crossover have shipped and I get them Monday/Tuesday of next week. I will likely use a good portion of the Thanksgiving holiday to work on them.

I will not need to add the Torus back in. The Pure Low plays down to 10Hz. So it will be Pure Low from 10Hz to 120Hz.

~Todd

OK! Look forward to reading all about it! Thank you!

 

[sbnx]

A small update...I received the Atma-sphere class D amps and the Danville DSP Nexus last Wednesday.

I got the amps unboxed, removed the Rowland Model 6's and placed/connected the new amps. Turned everything on and nothing blew up so that was good. Immediately the noise went away. Quiet as a church mouse. I was very happy with that. The gain of the Rowland was set at 32 dB and the gain of the Atma-sphere is spec'd at 22dB. I was expecting to have to turn the volume up a little but once I started playing music I think I need to take a tick or two off the volume. The panel needs to be fed with lots of instantaneous current. The Atma-sphere is doing this in spades. The sound is even more dynamic and clear souding. The Rowland sounded lethargic by comparision. I was initially concerned about the ability of the 100 Watt class D to drive the 90dB sensitive, 2.5 ohm load. But I should not have been. There is no issue here. I have been running the amps and panels to get them broken in. I left them on overnight at a moderate level. When I came in the the next morning the amps were still just room temperature.

I got the DSPNexus unboxed and had to remove a loose screw from inside the case. I worked on getting the software installed on my laptop. This is not a plug and play device. If you get one you either need to be proficient at software and DSP or have your dealer do all of the setup for you. On the plus side it has ultimate flexibility in how you want to build the filters to control the subwoofers output. I ran into a little snag and got stuck getting the laptop to connect to the DSP. As it was the Thanksgiving weekend I had to wait until today to contact them. Got that sorted out so hopefully will get the inital testing (to make sure all of my filters are working as they should) done sometime this week.

I mentioned the flexibility of the DSP. I can build all of the elements on the canvas and compile them. For example, I can have a Bessel, Butterworth and Linkwitz-Riley crossover each set witht same parameters. I simply feed these into a multiplexer and then I can easily compare how each one sounds by clicking the switch on the multiplexer. That will be cool.

In the meantime, I worked on the integration some over the weekend. Not as much as I wanted but made some progress. I got the right on matching the left pretty well. Yesterday I focused on rake angle. The rake was at about 0.034 back. There was a good bit of bass "ground fog". I raked them back some more until I ended up at about 0.12 degrees. Much clearer sounding. Still have more work to do before I am fully satisfied with their placement but already they are scary good.

 

[sbnx]

Been working a little here and there on integrating the PureLow. I have a little more work to do but overall exteremly happy with where it is now. I realize some of you are not measurement people but I thought I would post a waterfall plot. I think with a little more positioning work I can get rid of the 22Hz tail. This is room mode related so I just need to move the purelow a little more to get it out of that zone. But even with that tail you can see how fast the sound stops.

The crossover point is 30Hz with a slope of 18dB/Oct. There is no DSP applied. Of course once I start playing with the Danville that will change. Will just have to see if it is better. You may notice that the level is a little lower below 30Hz. That is because it scares me to turn it up more than this.

~Todd