Axiom Home Page Forums General Discussion Stereo Two curves is enough

Two curves? No. Great thread idea!

How dynamic does the Middle T sound vs an M60? How exciting? Can an FR curve tell you that?

I agree that the new adoption of klippel by more “open source” enthusiasts is awesome. But I think the more data the better.

Comparing the polar response plots of speakers allows some prediction of their sound intensity. Probably the most ignored and important metric when it comes to the subjective impression of bass in a room.

The JBL 4367 breaks the rules of the other speakers you mention, yet it is the speaker Erin would own if he could. He is campaigning pretty hard for one. I hope Harman gives him a pair!

The polar plots are incredibly important. Those and directivity index.

A family of FR curves can tell you that. The family would consist of the listening window and sound power at various SPLs.

The plots below are for the Model T Signature. The top plot contains the LW and SP at 1W input. The bottom plot is the LW at two different power levels. The bottom pen is at 1W input and the top pen is at the power threshold where compression (thermal and/or dynamic) begins. It would be reasonable to expect the LW and SP curves are all similar between the two pens shown.

As for the bottom plot, it only exists for the Model T. No other Axiom or Bryston. So it's impossible to compare the dynamics across Axioms or Brystons.

Researching this topic is fun. Buried in the data (all of which are available in the public domain, kudos to Harman, Axiom, and Sausalito), it's clear from the NRC research that everything points to the amplitude response as being the most important factor in selecting a loudspeaker (which includes deep bass). Dynamics and SPL matter, so that's why every manufacturer has multiple sized offerings. The other stuff like spaciousness and spatial clues are room and placement dependent.

What's problematic is that it took me years to distill this wisdom. Even up to last month, I thought Axiom's talk about neutral loudspeakers was marketing fluff.

https://youtu.be/igzzXKAqmi8

There is so much contradictory voices out there that say you can't have audio goodness unless you have this next thing (active crossovers, active EQ, AMT, etc). I partly blame EAC, Audioholics, and ASR for the confusion: they throw a lot of data at you while ignoring the two measurements that actually matter; and they spend most of their energies evaluating products that don't solve a real problem (DAC's, interconnects, amplifiers).

That JBL has directivity issues in the midrange between 500-1000 Hz. I hope this thread taught everyone reading it the skill set in identifying it immediately just from the listening window and sound power.

I should probably quit now, a minute discussing audio is a minute not enjoying music.

Oh, and the user interface issues of those review sites is easy to fix. Assuming that our assumptions are correct, just place a graph of the listening and sound power against a band indicating audio perfection (and it's likely a band +/- 1.0 to 1.5 dB wide). Then talk about company, construction, price and market position against rival products. Leave out the other graphs and subjective impressions or put them on the last half of the review.

After all, you wouldn't clutter up your dashboard with oil pressure, clock, fuel gauge, and compass meters that are the same size as your speedometer and tachometer, would you?

Yeah. Its trash. Bummer.

I checked my hypothesis with ASR's Olive scores. The straight lines of all the Axiom and Bryston models (except the Mini A) imply an Olive score of 6.5+. Every score between 5.0 and 6.5 have small but noticeable deviations from straightness. Anything below 5.0 and you can see major flaws.

And we seem to have broken Bryston's site.

Sean Olive on Predicting Loudspeaker Sound Quality and Listener Preference
https://www.audiosciencereview.com/...d-quality-and-listener-preference.26815/

Within the ranks of Harman there was dissention between Toole/Olive and other designers.

A recent interview with Greg Timbers touched further on the idea of sound intensity as a factor of reproduction not tested by the Harman scientists, nor weighted in the preference score. Its a pretty enlightening vid if you have the time.

Ultimately Great measuring speakers can be entirely boring and disengaging. I altered my curve in my setup from “perfect” for this reason. It sounded flat and non dynamic. Honestly, I measured the in room response of my M5HPs at the mlp in my 2ch room and translated that room curve to my theater mains with Dirac. Bingo!

There is a happy middleground I’m sure, but as Greg mentions in the interview reducing a speakers sound to a graph or number is not possible. Troels Gravesen agrees, and he is lauded as the “best” open source designer on the planet.

Dynamics cannot be measured with distortion or compression plots. Those only reflect max spl before bad things happen.

In a post earlier this year i did provide a paper written and published by Olive that demonstrated the concept that "all" listeners fall into a category of preference for a flat response curve, but also that there are small variations within the range (as to be expected for confidence intervals in any dataset) where preferences included small bumps in treble and bass off the flat response. When you look at the frequency response of really good speakers, those subtle differences in bumps or more humps/valleys in certain frequency ranges and to a certain extent (not too much or too little) can set one's personal preferences specifically to a speaker brand/model OR through the use of sound engineering like Dirac or Audyssey.

In short, i have no doubt that a best sounding speaker is one that is at it's basis 'neutral' and generally flat, but that with small tweaks, people find what they feel sounds best to them (at least to those who aren't trying solely to shop with eyes and wallets as the metric for quality).

I had a listen to that interview by EAC. I can see how heat soak affects dynamics, and why large drivers, enclosures and voice coils are the way to go if you wanted high SPL.

It's bizarre that of the measurements that we have, only about a third to half of the Revel and JBL models measure well by NRC standards. I take it that good industrial design and having a lot of models is the priority, rather than have a handful of models in a variety of form factors.

I also get the impression from multiple interviewers of alumni and current researchers that Harman is a Darwinian organization ruled by a culture of fear. haha