Axiom Home Page Forums General Discussion Advice from Axiom Owners M80s or LFR660

I was all happy with my planned M80 purchase when I broke my rule on "weird new-fangled stuff" and read a few threads on the LFRs and am now intrigued.
For a two channel music-only system (no sub) would you guys think the M80 or the LFR660 would be the better/more satisfying choice? I'll add that I don't really need M80s in my living room, the M60s would be sufficient; I've just always wanted a pair of M80 and figured what the hell, why not. (My room is 19^3 x 13^4 x 8; there are adjacent rooms that roughly equal the volume.)

Also, a secondary question - I've avoided this kind of purchase in the past because I'm afraid of hardware obsolescence. Meaning if I buy a good speaker I'm fairly certain I'll be able to listen to that speaker 20-30 years from now on whatever receivers they're making then; but if the DSP for the LFR breaks and Axiom has moved on, I'm stuck with a pair of expensive door stops. So, if you run unprocessed (non-DSP'd) amplification into just the front channel of the 660, does it perform like an M60?

The LFRs, without DSP, don't sound like their passive siblings.

The LFR660 would be better than an M80 for your space. The M80 will boom like the Dickens. Every Axiom passive I've had in my similar-sized living room has boomed - some worse than others. Even M2 bookshelves and OW although those needed only a touch of bass attenuation.

The active LFR1100 have been the only speakers ever that have not needed any type of correction in my 2000 cu ft living room or 4200 cu ft main space. The bass is something to behold!

One look at the frequency response curves of the M80 vs the LFR660 tell me the 660 will be better. Just look at how much better behaved the 660 curve is particularly in the bass. Sorry...Andrew and Ian really tried with the M80 but it's a bit of a beast to tame.

One other thing. I expect the 660 will give you improved imaging and soundstage. It will acoustically disappear better too. And it will offer higher fidelity across all bands. I guess that's 3 or 4 things.

Would / should these comments specify HP woofers versus non HP. I can’t recall if HP just really means more power handling fir higher spl or an actual change in bass notes or tone quality. I’m guessing it’s more about power handling than tone quality. I can’t see AXIOM doing that when they are about equality in quality and sound / tone from all the different speakers in their lineup.

Please correct or clarify here mojo. I have a feeling you ll know. Thanks.

Do 660/880 come with HP or reg woofers?

Edit: I can’t recall where it is..... but I remember a post about lfr and hp woofers coming with them or being able to choose. .....

The HP woofers are more linear than the standard woofers at higher SPLs. Axiom has never said above what SPL the HPs are recommended. Based on my listening, if you want to hit clean peaks above 100 dBC at 14 feet away without a sub, get HP drivers. Or, if you don't trust my hearing, ask Axiom to make a recommendation based on your application.

The LFR1100, M100, M5 and QS10 come with HP woofers. All other Axioms with a dedicated woofer come with standard woofers and HP are optional. The M3, M50 and QS8 are not available with HP drivers because the HP driver can't do the midrange like the standard woofer can.

I appreciate the replies. And now I have a harder choice to make ... well, I have time. I may try to see how Axiom feels about my trying both out. And I'll probably go with HPs, just because.

>> Every Axiom passive I've had in my similar-sized living room has boomed ...

Mojo, I do have side questions for you regarding the boominess. My M22s were definitely not boomy, and even the M5s in my small enclosed12x13 room don't sound boomy. In fact, I just looked at what YPAO did with the calibration and on one channel it *increased* the bass from around 100-200 hz! (Ironically, the 1st song I played on the M5 - Ana Popovic, Unconditional - did sound boomy and I said "uh-oh"; but then I played it elsewhere and found that it was just a boomy song.) But more interesting to me is that I read the LFR660 and M80 curves differently than you do. To me it looks like the LFR660 would have more of a natural low-end bump (kind of like the M3); the M80 without HPs looks flat in the low end with an even lower plateau from 30-60 hz. So, why am I reading those graphs 180 degrees differently that you are?

Cork, first I have to say that one can never judge performance by a few curves. However, I have the benefit of being able to leverage my experience with various Axioms, in my rooms, against published curves. So I feel somewhat qualified.

I have never tried the M22. But, knowing how the M2 performs in my living room, and looking at the M22 vs M2 curves, I would place a strong bet I wouldn't have to move the bass from neutral. If I wasn't using a sub, I'd likely have to boost the bass a bit. Note the M2 does have a bit of a bump between 70 and 100 Hz. The M22 doesn't.

Do you have the M5 a few feet away from the front wall? Do you have them crossed to a sub? I think Trevor has them in a similar-sized room, a few feet from the front. It also depends on how lively your room is too. I can say the M5OW are much better than the bookshelves in my living room. I turn down the bass on some tunes but not nearly as much as the bookshelves.

Another possibility is Axiom has been messing with the M5 curves since I got mine but that's just speculation on my part.

Regarding curve interpretation, these are the curves I'm looking at:

M80: https://www.axiomaudio.com/pub/media/catalog/product/m/8/m80_freq.gif

660:
https://www.axiomaudio.com/pub/media/catalog/product/l/f/lfr660.jpg

Just look at the smoothly declining curve of the 660 in the bass region. It is so free of the twin, 1 octave, low Q resonances the M80 displays.

Now look at the M100: https://www.axiomaudio.com/pub/media/catalog/product/m/1/m100_freq_graph.gif

Someone at Axiom (Andrew?) ripped their hair out trying to achieve that kind of performance. No resonances there.

Feel free to examine the passive and active LFR1100s too. Use the active as a frequency response reference for all others. After hearing the v4 M2, M3, M50, M5, M100 and the active LFR1100 in two rooms in my house, I can unequivocally attest the active LFR1100 is perfect. PERFECT!!!

The actives are perfect because their listening window and sound power curves ride on top of each other yielding an absolutely perfect directivity of 0 dB - across the entire range!!! And do you see any resonances? No. That's because Ian "erased" any resonances that show up in the spatial curves using the DSP.

Now compare the listening window and sound power curves across the M80 and passive and active LFRs. See how the directivity improves with the LFRs? And how it's perfect with the actives?

Why is directivity important? Because a directivity of 0 implies an omnidirectional speaker. And any speaker which is omnidirectional, with a smooth, declining response of 3dB per decade, is going to sound good in a room in the band where the speaker dominates the room. This cutoff point is called the Schroeder frequency. Below that frequency, the room dominates. In your living room, that's about 80Hz.

Now why is the 3dB per decade important? Because the Schroeder frequency isn't a hard cut-off. In the midrange, the room and speaker compete for dominance. If you make the response flat, you'll get a boost and that will make the material sound unnatural. This is what I don't like about the active Bryston curves. They've gone for flat response. Sure looks good on marketing material.

Now look at the lfr bass response. See how it's a smooth, declining curve? That's the speaker saying, "Room, I know you're in charge. Boost my output, baby!" And OMG, is it ever right on the actives!

Getting back to bass, it's terrifically important. Most of the problems I had with M80v2 were bass-related. Not good bass screws up the rest of the response.

Now you might say, " So what? I'll use my processor to do auto-EQ." But here's the thing. EQ can't fix bad directivity. And remember directivity is important so you can hear a large soundstage with diffuse yet excellent imaging just like a real performance.

Or you might say, I'll use a sub. That may help but a speaker like the M80 will continue to pump out the bass because it's output is not steeply cut off. Those two resonances will still be there, BTW.

Axiom is telling you exactly what you're paying for. It's all right there in the curves. It's also important to note the character of the soundstage and imaging is similar for all products. And all this is achieved with the same drivers and similar cabinet design across all models.

Why statues of Ian and Andrew are not erected at the AES is absolutely beyond me. Harman has been struggling to produce this feat for decades with their fancy labs and Ph.D.s and two guys in shorts and sandals in the middle of a Canadian forest did it with no pomp and circumstance.

I feel like I just walked into the wrong physics class! That took me a while to unravel, but it was very interesting - thanks for taking the time.

Even after I broke down and read about the omni's the other day, I didn't bother with the active 1100 since it's out of my league. Reading about them was very interesting and the curves extra-impressive.

Unfortunately, some of the terms you used are foreign to me; others I haven't considered since Physics 202 (a long, long time ago). So a few more follow-up questions.

"It is so free of the twin, 1 octave, low Q resonances the M80 displays."
It sounds like low-Q is a bad thing; but I would have thought that a low Q would be desireable to reduce resonance. (I remember resonance from the Tacoma Narrows Bridge lesson; but Q is new to me.)
And the "twin" reference completely eludes me.

"Now compare the listening window and sound power curves across the M80 and passive and active LFRs. See how the directivity improves with the LFRs? And how it's perfect with the actives?"
I'm not making the connection between SP/LW and directivity. I had thought that SP and LW measure the nominal power of the speaker compared to the power in a typical room. Wrong? Right, but missing the connection?

"Just look at the smoothly declining curve of the 660 in the bass region."
I had thought that flat in the usable +/- 3 db range was better than a smooth slope. But I think you're point was that below a certain frequency the room will provide a feedback boost, so the declining curve is offset by that feedback. Did I get that right?
But, there's also an effective bump in that 660 curve from roughly 55-90 hz; I would have thought that was not ideal (albeit, only ~3 db).

On the more mundane side, yes, I'm using a sub (turned down at that), crossed at 60 hz; I didn't consider that on the effect of boominess. The M5 that YPAO boosted is 7 inches from the wall, but also right next
to the door frame. The other M5 is 20 inches from the back wall, but 4 inches from the side wall.

In listening rooms we are looking for a RT60 of 0.3-0.45s. Period. If the decay time of our room is shorter in duration than the recording's reverb (or decay at time of live recording), than the perceptual effect is we are in THAT acoustic space. The decay in the recording becomes the trigger for our brain's impression of space -not our room. Cool! There are many ways to shorten room decay time, but that is another story. Longer room decay times mean we are turning it up for perceptual dynamics. This loads the room harder at bass frequencies and causes other issues like clipping or driver distortion. This is why the other fellow had issues with a bookshelf sounding wonderful but a tower sounding all congested and distorted I would guess. We move the goal line further away when we dump more energy into a problem room already loaded with sound -chasing dynamics so it sounds "live"

The issue with Mojo's room is solved by Active LFR speakers, but that is not to say passives are at fault or him or anything he is doing. His room decay is a big factor. His space trades perceived dynamics for extended decay and sweetness. But he loves dynamics! We all do. Gotta have em! So, we turn it up louder because it is not perceptually dynamic until we do so. The effect is worsened on busy or dynamically compressed tracks. They don't sound dynamic until loud. Then it's just bad news.

Firing across the short axis loads the room at a higher frequency and is audible in a way not always liked. We prefer a wide\deep and diffuse presentation, and also real dynamics, but there is no free lunch. Omnis solve the issue in part because they give perceived dynamics AND a diffuse presentation without relying on the room alone to accomplish it with reflections. The LFRs goose up the delayed reflections, and are similar enough in response to the direct sound, that we don't have to drive the room as loudly to have a lush and immersive sound field above bass frequencies. The other solution is to employ speakers that cannot reproduce lots of bass at the problem frequency. Then you can strategically deploy a sub in a room nullpoint to cancel room modes on that axis.

Probably why the M2s are so well liked. Very easy to deploy in normal living spaces without causing bloom that erode the intelligibility of everything in music we like.

The LFR660s I'm sure are wonderful speakers. If you can afford them for sure go for it! I would! But there is a lot to be said for the role acoustics plays in a room. It is a tricky subject.

I'm a broken record. But pop a balloon. What does the sound do? Remember the room you are listening in is essentially an EQ mechanism -one you can't turn off.

Comparing graphs, or product measurements is great as a stink check. Some products are just bad. But graphs are not good for much else once you plunk energy into a real room that is full of compromises. Things like this are why people get paid to design spaces for a living -to eliminate as many compromises as possible and save money for the owner\performance space. The other option is to spend the money on technology that makes these issues moot. LFRs!! We are paying for the efforts Ian and Andrew have already put into a product that ensure a fantastic outcome with less dependence on the room itself. A smart and value based choice based on my experiences setting up rooms and dealing with real life limitations for placement and treatment.

Do eeeeeetttttt!

Sorry about the physics.

If you look at the M80 curve down low, there is a bump between 30 and 60 Hz. There is also a second bump between 60 and 120 Hz. Hence twin bumps. My numbers are rough.

One octave is a 2-fold width in frequency. 30 to 60 Hz is one octave. 60 to 120 Hz is another octave.

There is also the decade I mentioned. A decade is a ten-fold width in frequency. A decline of 3dB/decade in the active LFRs is a good thing for most rooms for the reason I mentioned in the last post. It was a nice theory and when I heard it myself with my actives, I became a true believer.

Yeah...that bridge collapsed due to resonance. The Q was high enough within the wind frequency band to prevent oscillations from dampening out. The oscillations shook the damned thing apart. The very first day in my third year Control Theory class, we watched that old, black and white video. We were told we'd learn how to prevent that shit from happening. Speakers are no different. Thankfully the voice coils ignite before the speaker blows apart...LOL! I know. I've ignited voice coils and saw blue plasma behind the screen of the tweeters.

Q is simple. It's a ratio. It's the ratio of a resonance's center frequency to its bandwidth. A tuning fork has a huuuuge Q because it's bandwidth is almost zero. A 440Hz tuning fork resonates practically at 440Hz. It could also be the ratio of the energy stored to the energy dissipated per unit time. So if you look at the first bump in the M80 curve, the center frequency is at about 45Hz. The bandwidth is 60-30=30 Hz. So the Q factor is 45/30 = 1.5.

But forget the math. I'm not an expert in the perception of resonances for audio. Toole though says if you see a bump like that M80 bump over an octave, then it's audible. I believe it because I can hear it.

Then, like you raise, there's the question of high Q - sharp spikes in the response - vs. low Q, which are more gentle bumps. What you see in the M80 down low are gentle bumps. Now, if you look right at 325 Hz, you will see a dip. That might look nasty but it's nothing to worry about. Why? Because even though the dip looks sort of deep, it is quite narrow in bandwidth and your brains-ear will ignore it. But if it was a sharp, large spike there, you'd hear it I'm sure because it would activate your neurons. You'd likely hear it as a dull buzz. Why? Because more energy is being stored in the material that is resonant, causing it to move and make noise, rather than dissipated.

So, look for bumps and dips across the frequency response and ask if they might be audible.

The Listening Window is an average of the curves +/- 30 degrees in the horizontal plane of the speaker and +/- 10 degrees in the vertical. It's called the Listening Window because most listeners sit somewhere in this range.

The Sound Power is the average of all curves around the speaker both in the horizontal and vertical planes.

So now if you think about it, if the SPL for the Listening Window is identical to the Sound Power, the speaker must be omni-directional. The mathematical difference between these two curves is the directivity. If they're both equal, then the difference is 0 dB of sound pressure and the speaker must be perfectly omni-directional.

The declining curve of the LFRs is indeed offset by room boost. You are correct about that. The M60 is that way too BTW. Just maybe not quite as linear but that's just splitting hairs.

Yup, there is indeed a bump between 55 to 90 on the 660. But I bet it sounds nice. If you don't want any bumps, check out the active LFR1100. I know you said you can't go there but it's fun to just dream.

https://www.axiomaudio.com/pub/media/catalog/product/l/f/lfr1100_active_graph_1.jpg

Using a sub on the M5 certainly helps. I was not crossing to a sub. I also have mine placed across the length of the room rather than the width. That accentuates the bass.

BTW, since we're talking about peaks and values on curves, check out the M5. Someone may look at that and say "OMG, look at all those ripples. I'm not buying it." But you and I and others know different now. None of the ripples are audibly significant except for that first bump which is rather pleasing for the majority of rooms. And, all the ripples show up in the listening window and sound power curves and therefore get sort of averaged out by the ears-brain.

https://www.axiomaudio.com/pub/media/catalog/product/m/5/m5hp-listening-window-and-sound-power.png

So you can see now how much goes into understanding and interpreting these kinds of curves. I'd say Axiom has reached this pinnacle in understanding after 40 some odd years of beavering at it. They know the bumps and dips that really matter. Unfortunately, they can't flatten them all with passive speakers like the M80 and that's where fully active architecture comes to the rescue.

That was supremely interesting - thank you very much Mojo and TrevorM !
(I don't think I'm quite ready to apply to Axiom, but I think I can now test out of the intro course.)

TrevorM, I'm definitely doin' it ... on one of them; just not until March.

Mojo, this is not the most important take-away, but what I found interesting was the frame of reference difference. I was focusing on x-axis performance, so to me I saw the low M80 having a plateau; you were looking at "average slopes", so you saw the lower M80 as a bump.