Axiom Home Page Forums General Discussion What's New At Axiom LFR1100 Active

As some of you already know we have been working on an Active version of the LFR1100. The advantage to the active version is twofold. Since we have a DSP for each speaker controlling the five groups of drivers (Front Low, Front Mid, Front High, Rear Low, and Rear High) we are able to create a more refined family of curves in the "Spinorama" to achieve a new level of accuracy. There is also the advantage of being able to achieve a higher maximum dynamic power reproduction by eliminating the internal crossovers and being able to dedicate an amp channel to each of the five driver groups. It is very exciting to see it finally coming to fruition.

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Wow ... once you have experienced a dedicated amp for each set of drivers with no crossover, regular speakers just won't "do."

The problem is we love our 1100's. Ian, you are a troublemaker.

I need M5 and M100 to LFR upgrade kits.

Oh please Mr. Chase. Describe for me what I will experience.

I've written out the Laplace transforms for active and passive speakers on the napkins in front of me and clearly see how poles and zeros will shift on the root locus. For the life of me though, I can't resolve the synaptic response eigenvalues to determine my emotional response.

So please tell me. Will I experience a rhapsodic rapture?

Can't wait, Ian. This will be a fun road to go down.

I want to go down this road too! Charles, please take me with you.

I see the LFR1100 has gained a rear sphincter.

And it will reach 124dB in room at steady state and up to 129dB peak! I think at 130dB, the covariant quantum fields that comprise our universe start to break down. LOL!

According to the product page, these will offer pin-point imaging while expanding the soundstage.

With my non-LFR v4, I swear one can be fooled into believing I have surround on most songs when in 2.0 or 2.1. I haven't tried with movies.

With the LFR Actives, do I need the 160 and QS10? Do I really need an 800?

Think you'll have to come out with a 10 channel amp to go with.

Or perhaps put the active crossover in a 5 channel amp ... that way one can get each closer to the speaker ... or just put the whole thing in the speaker. Unless you need both channels to process the LFR signal ... (which I'm thinking might be a real possibility)

Ian, how is the directivity on those active LFRs? Are you able to get the listening window and sound power curves to pretty much lie on top of each other?

Hi rrlev,

An ADA1500-5 per speaker would work really well. Since there is one DSP per speaker the amp/DSP combo can be over by each speaker. I did think about putting the DSP and an ADA1500-5 in the speaker. It would save a lot of wiring as you would just need to plug each speaker into the wall. Our 4in1 Transmitter/pre-amp/AxiomAir could send the information to each speaker wirelessly.



But the speaker would have to get quite a bit taller to house all this amplification and the DSP. As it is you could still use the 4in1 Transmitter/pre-amp/AxiomAir and have the receiver mounted in the DSP for each speaker so the wiring would be minimal, just 5 short speaker wires if the amp is near the speaker and the interconnects from the DSP to the amp.

Hi Mojo,

Yes we are. It is pretty cool to have this much control in the design phase. The flip side is the mathematical nightmare of all those curves coming together. You have five distinct radiating patterns to work with to give you the final result at each 7.5 degree increment in the Spinorama. Since adjusting one affects all the others you can kind of get the picture.

Then we're all in big trouble. We all need to upgrade to LFR actives.



Yes, that's why we need one driver to rule them all. But it's so much fun to play God with speaker systems.

So if I popped my head in next Thursday, could I see a working demonstration? Just Wondering??

Hi Matt,

A week or two later would be better if you can swing it. Right now everything is at my place.

Win win

Mat, what Ian isn't telling you is that he blew the sh!t out of the test gear Andrew gave him. He hooked up 5 ADA-1500s to each LFR. When that "worked", he jumpered the ADAs for bridged mono mode and launched the HP drivers across the room with smoke trails and tendrils of voice coil trailing behind them. At least that's how the dream I had last night went.

Lol

He really is running 5 ADAs per active LFR1100. It's a good assumption they're bridged. He must have them 50 feet apart and sitting at least that far away. I'm sitting 10 feet away from my M5s which are 10 feet apart, listening to Burning Down the House through my puny Pioneer at -10 and it's more than enough to rattle my rib cage. Clean too!

One ADA-1000 is more than enough for my M100s for either music or movies. That's at 13 feet away with the M100s 12 feet apart in a 4,200 cu. ft. room. With the ADA-1000/M100, I can turn my Onk up to 0dB and it's loud and clean! It's pretty cool but only tolerable for songs that are relatively quiet with huge swings. A real treat.

The 1500 is absolute insanity. I cannot shut it down and it brings the M3 and M5 to their knees. I am sure I could ignite the M3 with it and while Ian said to give the M5 all the 1500's love, I can't bring myself to do it. Not the M100 though although I am sure it's pretty close and the voice coils are gasping for air. Those HP drivers are looking like Marty Feldman's eyes. I had my muffs on and this time ear plugs as well but can still hear the huge, enveloping sound. The hairs on my arms were standing up like a werewolf in heat. LOL!

Well, let's face it. Active LFR is a costly proposition. I guess there are going to be those who money doesn't really stand as an object when it comes to sound, but the question to be asked is would those people also not be part of the snobbery that would question the pedigree of Axiom and just buy into some more well-advertised brand that has better name recognition with their other snob minded acquaintances.

I have a pair of LFR1100s. I find that they do play quite well and can give me a whole load of enjoyment. I have tested an ADA1500 with my setup in my room and found no real advantage over the ADA1000 that I currently own.

I got an email from Axiom offering me to move up to Active. Why would I go on blind faith that it will be that much better? I know the side of diminishing returns and now that at this point in the curve that getting a small fraction better sound can cost quite a large investment in cash.

It comes back to the so misquoted statement that I made. The improvement in sound I got from going from an older set of speakers, in my case a pair of Energy C3, to a set of M3v4 speakers was gigantic. The M3 are about $600. The improvement from the M3 to M100 is there, but not 4 times better considering the cost of the speakers are over four times the price. If you moved to the LFR1100 your cost jumps up well over 10x the price.. do you honestly think you are getting that much jump in sound? Yes it is bigger and envelops you more. But it is a night and day better sound like going from a 12" black and white TV to a 100" 4k laster projection?

If I was to trade in my LFR1100 for an active system, I would want to take a listen with a blind A/B comparison to say yes I can hear an improvement over what I have now and it's worth the extra cash out of my pocket to get that sound.

I am just outside of Dwight for the next 4 days. If Ian wants to sell me on going Active, then show me what it can do.

Well...let's see. The M3s can take 200W average and 800W peak. The M100s can take 600W average and 2400W peak. Not 4 times better but certainly 3 times...if your application calls for it.

The quality of the lows, mids and highs of the M3 cannot be compared with the M100. Once you hear the two beside one another, it's like night and day. A novice would very quickly pick the M100 over the M3. In fact, many novices have at my place. The 100s are more than 4 times better in this department.

You need twice the amplifier power with the M3 to get the same SPL as the M100.

The soundstage and imaging of the M100 though is definitely not 4 times better than the M3 but it is wider and taller. This is an amazing feat of engineering on Axiom's part. You will get very similar imaging and soundstage from the least to most expensive speaker. That soundstage and imaging is holographic! As you move up, you will get improved width, improved fidelity across the entire audible range, improved micro and macro dynamics and improved dynamic range. But the character of the entire family is the same. Bravo!

As for the LFRs, I don't know because I've never heard them.

If I had LFRs, I'd trade them in for the actives and if the actives weren't better in my space, back they'd go. I am willing to wager though, the active LFRs will image significantly better!

P.S. The 1000 can drive the M100s very loud and clean but it gives up long before the 1500. The 1500 also does a better job with the lows if playing the M100s full band. Of course this is all academic if your application doesn't need that kind of power. This is probably quite the same with the LFRs as you've found.

How does one actually power all of those ADA's? I thought I was going nuts with building 4800W of circuit capacity into my media closet.

If you are talking about powering a pair of the active LFR1100, you could use two, 5-channel ADA-1000s. That's likely no more than 1800W. That may work well for a medium size room or even a large room if you don't want to open it up too much.

Recall the nominal (average) power is far less than the peak. The breaker can take peaks without tripping.

So by your logic, a 600hp BMW M5 is a far better car to drive than my 140hp Kia Niro. Yes, it is far more expensive and has better specs all around, but put them both on an LA freeway in rush hour and I bet you'd far prefer the Niro as it gets to use the HOV lanes. Power is meaningless unless you are in an environment that lets you use it.



I just call utter bullshit on that! Yes the M100 can produce a lower low. But the mids and highs are not that far off. Again, I gather that you when doing your demo are following the Spinal Tap and running your amp to 11. At realistic listening volumes in an average sized room, the two are not that far apart. Not everybody wants or has the need to listen at 100db of sound. And I think that is why I can't seem to take most of your sound rants seriously as I feel you are living in your own world that the vast majority of the rest of the population simply don't.

I still don't see the point of spending my money unless I know that it will give me something in return.

I suggest you read my posts a little more carefully.

The M3 and M100 are indeed on opposite sides of the spectrum when it comes to fidelity across the entire audible range. That holds true at any SPL from -25 on my Onk and up. Of course this depends on how critical you want to be about fidelity but I can tell you those who have listened to mine side-by-side are not at all critical when it comes to sound, and they immediately pick the M100. Not so between the M3 and M5 but even there, when they listen more closely, they pick the M5.

If you're familiar with my posts, you'd know I don't listen loud. All my buds listen even lower because they're quite sensitive to SPL.

As for my posts, I lived for almost 12 years with my shitty v2. I have great reason to celebrate over my v4 which are at least an order of magnitude better than v2. How about celebrating with me?

Hi Matt,

I would be careful not to confuse the cost of the amplification with the speakers. For $5,700 you get both omnidirectional speakers and two fully balanced DSPs capable of controlling 10 individual channels. In a smaller room where you would not be throwing a party, two ADA1000-5 amplifiers would be loads of power for the LFR1100 Actives. You already know what the passive version of the LFR1100s can do so I would think of it from the perspective that for around $700 more dollars plus some extra amp channels you can take things up one more notch. And beyond that I would put out the challenge that you may not be able actually buy a better sounding pair of speakers for any price.

Hi bman84,

As Mojo mentioned it is all about the available peak power to avoid any possibility of amp clipping no matter the dynamic range of the source material. The actual continuous power consumption will be easily handled by a normal wall circuit. This said, I don't think you would want to turn on all the amps at the same time or the inrush current may cause the breaker to blow. There is a lot of capacitance there to handle those dynamic peaks looking for an initial charge.

Oh my... I just noticed these are ready. Given that I haven't had time to unpack and set up my LFR1100's yet I am thinking hard about trading up to the actives. I have always been a big fan of bi- and tri-amping, although one of the attractions was being able to crank the volume up until the bass was clipping without frying the tweeters. I don't do that no more... trying to save the last of my hearing.

I ordered a 4 channel ADA1500 with the LFR's, so thinking about maybe using that for woofers and front mids then adding a 6-channel ADA1000 for the rest.

I always used to run larger amps for the lower frequency channels so that might be an option here as well, but don't know if ADA1000 and 1500 have compatible gain and polarity (ADA1000 is 1.2v for full output while ADA1500 is 2V for full output so it seems promising).


I feel stupid asking this since I own a (still in box) ADA1500, but are the ADA power switches mechanical or electronic ? Thinking about the situation where you get a power outage then power comes back on again... although I suppose in that case the caps might maintain enough charge to limit the inrush. I guess that leads to a "do you only turn ADAs on when using them or leave them on 24/7 ?" question that belongs in another thread.

Yes, email already sent to Debbie.

Totally fair question. There is definitely not a linear relationship between cost and performance, and the knee of the curve is somewhere around the M3. Past that you get continued improvements in sound quality plus the ability to fill larger rooms (or play more loudly) but you are definitely dealing with diminishing returns per $$ and your money is getting you nuances rather than night-and-days.

One of the reasons I was so excited about the M5HP was that IMO it gave Axiom a "this is as good as most people are ever going to need" bookshelf speaker, which I felt was a gap in their lineup previously.

That said, if you do have a large room to fill then going to larger speakers does give you more than a nuance in benefits. For a smaller room it gets tougher to justify going much past M5HP or M60 from a value perspective, although the larger speakers are still going to sound better even so.

Going from regular to LFR is arguably another expensive nuance, but one I definitely wanted to try.

Since I don't play my system very loudly these days I don't expect to get more than another nuance going from passive to active crossovers, but (a) I grew up on active crossovers - talk about a mis-spent youth - and (b) I really like the work that Ian and Andrew have been doing and am really interested in the possibilities that come from doing the active crossover in a DSP rather than a few op-amps.

Bottom line - do I expect a big difference between passive and active LFRs ? Nope. Do I expect some interesting nuances which I might or might not find really desireable ? Yep.

I do agree with your point about being able to listen to the speakers... the "internet direct" model works exceptionally well with smaller speakers but starts to get a bit strained once you are talking about LFR1100s and a stack of electronics that comes up to your waist. It probably would be worthwhile for Axiom to set up a listening room with a permanent set of LFR's that can be A/Bed with other speakers from their lineup for a while, just so more people can see and hear what they can do.

If you are not able to connect with Ian while you're up in the area and I do go ahead with trading to the actives, I would be happy to haul them out to your place so we can A/B them with your speakers.

John, I've discovered some very interesting things in my listening sessions with the M3, M5, M100, 1000-3 and 1000-5.

First, when watching movies, the mains don't matter. Surprise! I can't hear a difference between any of the above models in 5.1.

Second, when watching movies, the external amps don't matter. Surprise! My Onk is more than good enough for my 4,200 cu. ft. room and 13 foot MLP.

Third, for 2.1, the speakers matter a lot - a lot more than external amps. As I've said umpteen times, the soundstage and imaging are very similar between these three models and that's where it ends. The M5 is worth every penny over the M3. It is more than twice as good. No one I know wants the M3 when they hear the M5. The difference between the M3 and M100 is very stark. Not so between the M5 and M100 but when one listens closely, one hears things they can't unhear. The hand claps in Unsquare Dance sound like hand claps on the M100. On the M5, you know they are hand claps but they sound less human. You'd never know they can sound better than the M5 until you've heard the M100! My buddy (and Ian knows this) listened to my M5s numerous times and was very moved with the sound. But when he heard the M100s, when he heard those hand-claps, he wanted to buy them off of me. Then his wife stepped in and we all know how that ends.

Fourth, if you want the realistic sound of M100s, you better have a big room or they will boom like the dickens. You can plug the ports, apply XT32 and they'll still boom. Besides, plugging the ports changes their character. This is why I find the M5s to be the sweet spot. They work in big or small rooms and they sound excellent enough.

Fifth, for 2.1, external amps can matter. If you are planning on running the gain around 0, even the M3 sounds better with a 1000 but I wouldn't recommend running an M3 that loud because it's at the limits. If you're running M5s, the 1000 may not be enough for some songs unless you're sitting 8 feet away. And if you're running the M5s that loud in 2.0, you will hear distortion because a single HP driver can only go so far. If you're running M100s, the 1000 can be very good and anything more is for longer listening distances than mine or for very short periods of listening otherwise you will go deaf. Even the 1000 though has its limits and I can shut it down before the Onk pre-amp, M5 or M100 give up. That's where the 1500 comes in and can take the M100 right up to its compression limit.

Sixth, even in a largish space like mine, with M100s, I can live with my Onk with no regrets. Not so with M3s or M5s because in 2.1, they don't have the 'nads for some very dynamic material.

Yep, that pretty much matches my understanding although I have not yet had a chance to listen to M-100's. The jump from M3 to M5HP is significant, and going to tower speakers makes a difference when you need to fill a large room.

I am very happy with my older M60ti's for HT and have no plans to ever replace or upgrade them. I do need to get off my butt and hook up the new UDP-203 via analog to the HK630 so I can have 7.1 and then wire up the M2ti's as rear surrounds, but that's as far as I ever expect to need to go.

That said, I haven't even been up to the loft (where the HT is set up) in a couple of months.

I don't know what's going on with you, man. Where are your priorities? LOL.

Strange. I would have thought that movie tracks could be just as demanding as music, especially with sounds like gunshots/explosions, and dynamic classical scores. Maybe it's the center channel that matters most here.

Bman, you got that right about the center channel. I measured 16 times the power going into my 160 vs the M100s in a GOT dragon destruction sequence. I had 8W going to the M100s and 128W to the 160.

Also, it could be there's so much going on in movies, it's hard to be critical compared to 2.1 music.

Solid test material! 16x the power is pretty insane. That's a good point about critical listening as well. Holds especially true in when a lot of surround activity is present.

I find the maturation of Axiom to be interesting. When I first heard Axiom speakers in 1989, visited the factory and met Ian in 1990, joined this board in 2002, the basic premise was low cost, high quality sound. Real wood? Not a chance as the value is on the inside! Expensive speakers over $2k? Not a chance as that not be in line with the company mantra!

Now, dont get me wrong, I think the new products are exciting and could open the company and products to new fans. I have enjoyed the version updates and introduction/removal of new models (anyone still have a Sherwood receiver or the M40's - not to mention the original, non ASW AX3's that I first purchased)?

I think it is a great company, with solid leadership who are not afraid to push the envelope of busy and refine/design wonderful products! I cant say that LFR's and a stack of amps is something I have the desire to own anymore - that boat sailed with my Reference 3a Suprema's and Simaudio Moon amps in the 1990's, but I am glad the options are now there for those who do. Having heard the LFR's, EP800's and the ADA amps at the last Axiom anniversary party, I can say I wish they were around when I was heavily into gear as the end game - where now I simply enjoy the music/movies.

Congrats to Ian and team!

"I find the maturation of Axiom to be interesting."

Indeed! One of the qualities I love about Ian is his hunger for knowledge. Another is his incessant drive to adapt to that knowledge and create new frontiers.

I'm hoping an active LFR180 will follow before long, even if it means even more channels of amplification to think about.

Yeah, it's not like me to leave speakers unopened (or listening rooms unmolested) for even a day let alone a few months. Who knows... maybe I was subconsciously waiting for the active LFRs.

Charles, what the hell are we gonna do, man? All this audio innovation and addiction to pornaudio is gonna kill us!

If you can wait a tad bit longer, Axiom is working on new drivers. Apparently Ian was babbling during his nightly 2 hour nap and fortunately Amie was able to record him. He recited a recipe for quantum foam which they've been able to formulate in the thermo-forming machine. It excites quarks at the Planck scale for the ultimate resolution!

Can anyone tell me what kind of standby power each axiom DSP consumes?
How about a 5 channel 1500 axiom amp?

If I shut off or turn on power to the wall outlet which supplies the DSP and Axiom amp does it power down it power down and up gracefully?

Just wondering if leaving the active LFRs on all the time consumes a lot of energy and if it does would it make sense to switch it off remotely.

I'd say 10W for each ADA and DSP.

As for your second question, I'd direct that to Axiom. They may have an inrush current limiter that only functions off the trigger input or power switch.

Charles, regarding the LFR180, if we are to have active LFR1100s, don't you think we should have active LFR180s that have dual HP woofers on the front left and right?

It makes sense to me.

Heh heh.

Mojo,

10W sounds like a lot for a D amp ... is that a measurement??
The DSP box should be way below that ...

Also I take it that's when the amp's triggered
What is it when not triggered?

Rich

Never quite got the LFR center channel thing. Are we not trying to localize sound to the center of the screen??

Rich, it was an educated guess on my part from the stand-by spec Axiom gave for the DSP subs. I'll see if I can dig up the manual. It's not on-line.

Regarding the LFR centre, I expect the sound will still be localized to the center but it will sound wider and more dispersed like in a movie theatre. Perhaps it's only best for larger rooms like mine...dunno...I've never heard it. It's one of those mysteries Ian created, tucked away on the site, waiting for someone to discover it and yell "Eureka! It's freakin' amazing!!"

I want it!

Nothing in the manual on stand-by power and it's a PITA to try and measure it safely.

I think the idea is to try and provide a smooth continuum from left through center and right, rather than having only right/center/left positionings (oversimplifying obviously).

When I went from VP100 to VP180 I found that the center signal was now "wider" (not a surprise) and that the result seemed much more natural and true to the video (that was a bit of a surprise) as a result.

"When I went from VP100 to VP180 I found that the center signal was now "wider" (not a surprise) and that the result seemed much more natural and true to the video..."

Ditto when I went from 150v2 to 160v4. Plus, much higher fidelity and understandability.

Did you all notice the five position BGC switch on the active LFR DSP? Since there are 2 DSPs, the boundary gain can be adjusted on a per LFR-basis. This might come in very handy.

Your best bet for minimal power consumption and longevity would be to use a trigger to put both amplifiers in standby mode when not in use, or turn them off altogether using the rear switch.

Each DSP consumes approximately 9W.
An ADA1500-5 in standby mode (trigger off or front panel button turned off) consumes approximately 20W.
When turned on and active, the ADA1500-5 will consume approximately 90W at idle.

Thanks,

Andrew

I love the sound of toroid magnetostriction on the 1500 in the morning. Therefore I always turn it off to get that small joy in my life.

So LFR1100 Active uses 60W even when off ...

Indeed. 58W to be exact.

Are the DSPs tuned for each speaker? Which is what I'd expect on a high end active crossover.

Over time the DSP code is bound to improve. How will these updates be handled?

Just reread Andrews comments ...
think I understand

Front power switch is similar to trigger off (20W consumed in standby)
The rear power switch is completely off (0 Watts)
Is that correct?

Does the amp shut down and power up gracefully when using the rear switch?

Yes.

I've had no problem with turning the rear switch on. I've tried it with two 1000s and one 1500. There are no clicks, pops, farts or burps. On the 1500, when you turn it on, you will hear the pleasant sound of magnetostriction in the 30 pound toroid that graces the innards.

I have noticed when the rear switch is turned off on the 1500, and the front switch is still on, for about 753 msec, I hear a high frequency squeal in my VP160 as if someone quickly choked a squirrel. It surprises me every time, and every time I have to remind myself I don't house any humans or squirrels in my 160.

Being sensitive to phantom power (especially if it's over a watt, no less 58W) I'd like to propose that:

A) the DSP have a trigger which shut's it down completely ... and if there is any chance that there might be a transient on its output then the DSP also have a trigger out which shuts down the amp before the DSP (and turns it on after the DSP is settled).

B) the Amp shut off completely after say (10min). I can only guess that this is not being done because the power supply takes a while to come back up. For people who want instant on then maybe this option is switch selectable.

Thoughts?

What you're asking for is doable but it increases part count and complexity.

relay (preferably latching) or have a separate power module (TI makes a few single chip supplies which can efficiently supply what's needed at a few mW of cost)

Mojo,

You edited your post and left my answer hanging ...

in any case ... for the few parts it takes the product is greatly improved ... if you care about wasted energy ... not to mention paying for it (but I guess in the winter it's just adding needed heat) it's a no-brainer ...

Rich

Rich, I edited while you were posting your answer. It's actually not as simple as you proposed but yes, it can be done.

This begs the question - how many squirrels have you heard being choked?

Never seen one choking on a peanut? It must be Andrew's sense of humour designing a turn-off circuit that sounds like that.

https://youtu.be/xOcVuWMP9t8?t=15

I hope Ian is OK. Last I heard, he was bruising his corpus callosum trying to integrate the various driver curves for the active LFR1100 in the digital (DSP) domain. I hope he hasn't blown a brain lobe!

All is going AWESOME!

OMG! The Listening Window and the Sound Power are ONE! Ian, you did it! You will go down in the annals of speaker history!

It's so beautiful. I can't stop looking at it. 2.5dB attenuation per decade!

I'm still looking at those damned curves. I can't believe the Directivity Index is practically zero across the entire audible range.

Hi Mojo,

Bringing the curves together like this is working in the blind listen testing too. The realism factor has gone up another notch. I am really looking forward to getting this version back down to my place.

You don't need to listen to it to know it's full of goodness. I mean, look at those curves. Compared to the passive 1100, they are far superior. I have no idea how Mattmanhasgonebutisbackdroolingandskeptical can possibly live with his passive LFRs!

Ha ... so let’s widen the window ... 20,25,30 degrees? I mean measurement window ... how wide till you see a reasonable deviation.

Even more questions
What is the test setup .... you need to have walls to reflect off of ...

Nope. No walls needed. "Just" the Axiom anechoic chamber, a turntable, signal generator, mic, and waveform recorder.

If memory serves, there are two curves posted. The red curve is the on axis curve. The blue is the average response of curves at 7.5 degree increments in both the horizontal and vertical plane, or 48 measurements in both the horizontal and vertical planes.

It is also done in the chamber to keep any effect of the sidewalls, floor and ceiling from occurring.

The red curve is the Listening Window and the blue is the Sound Power. The Listening Window is 0 to +/- 30 degrees horizontally (phi plane) and +/-10 degrees vertically (theta plane). The Sound Power is a weighted mean of a number of curves: Axial Response, Listening Window, and Early Reflections.

I don't think Ian has ever said publicly what the angular resolution of those measurements is. And for all I know, Axiom may extend these curves beyond the nominal angular ranges I've described. The weights for the Sound Power are Axiom secret sauce.

The recipe is right below. You and your whole family can sing it to the tune of "We Three Kings from Orient Are":

We six curves of Axiom are
30 years old we've come so far
every one eighteenth pi rad, an anechoic curve we add
of spinorama data not scalar.

Refrain:

O curves of tone and SPL
curves with similar shape and flare
gentle slope, low Q nope
perfect sound these curves foretell.

Direct sound real flat without any gain
"Axial Response" that is my name
simple content, most important
over all curves I reign.

Repeat refrain

A "Listening Window" nine curves mean am I
0 to +/-30 degrees across, 10 degrees down, 10 degrees high
within a dB, these curves must be
for listeneners to joyously sigh.

Repeat refrain

Image width, stability, timbre to tame
+/-40, 60, 80 across and 50 down and high's the game
most that we hear, bounce from quite near
"Early Reflections" is my aim.

Repeat refrain

A speaker's signature doth we take now
weighted mean of 70 curves is how
downward tilting, no broad wilting
"Sound Power" curve art thou.

Repeat refrain

The "DI" curve is the cash cow
the "Listening Window" from "Sound Power" take away now
closer to zero, it's a hero
listeners will procalaim a big "Wow!"

Repeat refrain

One last curve is for finesse
"Early Reflections" from "Sound Power" we minus
lateral prophylaxis, from far-off axis
"Early Reflections DI" shows polar bias.

Repeat refrain

Low DI with curves smooth and similar
disperse the sound as not to be insular
audio pornography, via sonic holography
sharp images spaced out renders them singular.

Repeat refrain

Axiom's direct radiators sound great when they're played
sound power declining 3dB per decade
if that DI, is a bit high
constant, low DI LFRs can be yours via trade.

I thought that the listening window measurement is the average of 4 off axis measurements 15 Degrees left, right, up, and down from center. I’m sure someone will set me straight if I got that wrong ...

I’m sure it’s done in the anechoic chamber but I’d bet two walls of the chamber need to be covered (at least partially) or you would not be able to measure the Omni directional effect

All the chamber walls are covered with sound-absorbing material which renders the walls acoustically invisible and hence why I said "No walls."

You don't need reflections to measure the omni-directional effect because the effect is "encoded" within the curves. When you place the LFR in a room, the speakers interact with the room and the omni-directional effect within the curves is decoded thanks to your ears-brain system in that room.

The Listening Window is (traditionally) a mean of the curves I described but as I said, Axiom may be extending the angles to more fully characterize the speaker response.

Hmmmm .... We need to know the setup to understand what we are looking at. The curves from the front firing speakers alone or the curves from the front combined with the rear reflections. I’ll bet that the off axis measurement is not going to improve much if only if it’s the front alone. If the curves are synthized from the front and rear being measured separately (I.e. the rear driver needs to face the mic) then it’s not much of a measurement. If it’s a real measurement .... how would you propose to measure it.

It's the curves from the entire speaker. You put the speaker on a turntable and rotate it horizontally and take measurements. You rotate the microphone for vertical angles. The measurements are frequency sweeps across the audible range. You generate 234,389 curves and drink your face off and smoke the good stuff for 20 days straight to make sense of all of them. Then when you do, you go to the DSP and tweak all the filter coefficients, and then go back to the chamber and do it all over again until you have the angelic curves Ian posted.

I’m going to bed ... I think you should reread my post
BTW I do undstand what Ian means when he talk about the spinorama

You want to know how the rear measurements are taken and integrated with the front.

I will see if I can clarify these two measurements. The Listening Window and the Sound Power, or Total Radiated Sound Power, are the two main curves in what has been coined the “Spinorama”. Both these curves are averages of a "family-of-curves”, or amplitude response graphs, measured in an anechoic chamber. The Listening Window will always be an average of a group of curves centred around the on-axis curve. The Sound Power will always be an average of curves taken in all directions around the loudspeaker in an anechoic chamber. Exactly which curves are used, at which degrees of steps, and using which weighting will vary a bit depending on who is doing the measuring and when. This type of research began in earnest in the 1970’s when Dr Floyd Toole began comparing various anechoic measurements to strictly controlled listening tests at the National Research Centre (NRC) in Ottawa, Canada. I was fortunate enough to have been involved in this research at the NRC for eleven years. Over the years we were able to refine the importance of the various measurements taken based on the results from the double-blind listen tests. The magnitude of this research is daunting as you need to verify consistency in the double-blind listen test results across many people and environments. A handful of companies have continued the research since the NRC days, Axiom being one of them. API being another one, which is where Andrew was before Axiom. API, because of the Mirage line, did a lot of research into the nuances of omnidirectional loudspeakers on this research. When Andrew first arrived at Axiom it was really interesting to chat about our various findings since the NRC years. Following this time Version 4 was born.

For a conventional front-firing loudspeaker the Listening Window should be linear across the frequency band and the Sound Power should have a consistent tilt downwards from 0 dB in the low frequency to around -10 dB at 10 kHz when compared to the Listening Window. For an omnidirectional speaker the way to read it is a bit different as now you have the ability in the design phase to bring the Listening Window and Sound Power closer together. In order to maintain a proper spectral balance, you cannot just bring the Sound Power curve up to match the Listening Window, instead both need to move towards each other. By creating the LFR1100 Active we had an incredible amount of control over the five driver sets which allowed us to experiment with making the Listening Window and the Sound Power the same. I think you will love the result!