Evidence-based Speaker Designs

[Ilkless]

I'm sending an HR5 to Amir. I am very interested in the Klippel data as Ocean Way makes some pretty bold claims about this loudspeaker. I like the mini-Ubangi look, too.

A huge waveguide and wide baffle is quite unique for the price. Hope that translates to controlled directivity, low baffle step and high SPL while having a good FR.

 

[matt3421]

i see the smallest speaker they have is the Rixos-S (Grimani)

how much would a pair of those cost? i can't seem to find any place to buy their speakers

 

[Ilkless]

i see the smallest speaker they have is the Rixos-S (Grimani)

how much would a pair of those cost? i can't seem to find any place to buy their speakers

They are high-end home theatre installers, and so they don't seem to sell just speakers as much. The only prices I've seen are from the higher-end line - $12800/pair for the Delta, $18000/pair for the Tau. Granted, those are active speakers. Not sure how much the smaller, less fancy Rixos stuff would cost. No harm reaching out to them?

 

[amirm]

the ETC is a time-domain measurement. how exactly is the Envelope Time Curve "extremely unreliable measurement" when analyzing the time (and thus corresponding total flight path distance) arrival of indirect specular energy?

Because spectrum of the sound will determine its shape as much as its timing. High frequencies have a larger effect than low. From Dr. Toole's book:

Here is the spectrum and ETC differences:

Two identical sounding reflections (at threshold of hearing) show whopping 20 dB difference in ETC sending the viewer chasing ghosts.

The above is not a surprise to anyone with basic understanding of signal processing. But very non-intuitive to people outside of that domain. I suggest not using ETC or advocating it without understanding said science. Dr. Toole says it best after above example:

I explained all of this to you repeatedly in AVS Forum. Years later you are still repeating lay-intuition nonsense that misleads people into screwing up their rooms, spending a ton of money uglifying them to boot. Spend some time learning the science for heaven's sake.

 

[Ilkless]

I haven't read the whole thread yet, but can anyone tell me if Focal speakers have been discussed or will be discussed? They make some passive radiator models, both two-ways and three-ways that use aluminum inverted dome tweeters and a kind of flax material in the woofer/mid.

Focal is a good call, but they can be a bit inconsistent with engineering. Plus they are also very well-known already, with tons of discussion, using a very conventional format of speaker design. My aim is to mostly talk about less-known, engineering-focused brands here, especially those with more unusual and innovative engineering choices. You can't really go wrong with the Aria line of speakers. Some compromises, but also some stuff no one else is doing, and you can find them at very good prices on sale quite easily in the EU especially.

Also, to continue on the Ocean Way stuff. I love this trend of previously megabuck studio brands trickling down unusual designs into relatively-affordable territory. I just found out Barefoot has a new entry-level Footprint line with dual-opposed sealed woofers (6.5" or 8" depending on model), a 4" midrange and a Vifa/Scanspeak-style ring radiator. Clever to save cost with a passive XO on the midrange/tweeter, while using DSP for the woofer XO, where passive parts become expensive and too limited in performance. And the speakers have amplification. At $2,750 and $3,750, that is starting to get really price-competitive with many upper-middle-tier passive "hifi" setups once we add amplification.

 

[roland{at}GGNTKT]

Thanks for continuing to curate this list for newcomers. Should add the recently discussed GGNTKT.

Thanks, slipped my mind. Added. Tagging @roland{at}GGNTKT in this thread too, so he knows his speaker has an entry here.

Thanks for mentioning us and Model M1

I don't think it's inspired by the LSR waveguide. It's mostly a biradial horn, like some older JBLs.

The diffraction slot and wider directivity seems to suggest otherwise though, I thought biradials were around 90-degrees.

We don't use a biradial horn or a diffraction slot, although it might look so. It's a hand-optimized contour after many BEM simulation und 3D-printing, with a little narrowing in its entry:

It gives us a very broad 140° vertical dispersion (-6db) and is asymmetric in the vertikal plane (+60°/-40°), of course all constant in its operating range >1,5 kHz. A lot of engineering and prototyping went into this and it works out very well.

 

[Ilkless]

Thanks for mentioning us and Model M1

We don't use a biradial horn or a diffraction slot, although it might look so. It's a hand-optimized contour after many BEM simulation und 3D-printing, with a little narrowing in its entry:

It gives us a very broad 140° vertical dispersion (-6db) and is asymmetric in the vertikal plane (+60°/-40°), of course all constant in its operating range >1,5 kHz. A lot of engineering and prototyping went into this and it works out very well.

Thanks for the explanation, Roland. The "knuckles" reminded me a bit of the "diffraction blending geometry" JBL is currently using but it's clearly different in the details, and the polar response shows how optimised it is.

 

[tuga]

Would AudioKinesis fit the bill?

They now "outsource" their speakers but still make the Swarm subwoofer mesh:

http://www.audiokinesis.com/the-swarm-subwoofer-system-1.html

https://jamesromeyn.com/audiokinesis-speaker-design/#philosophy

 

[Ilkless]

Would AudioKinesis fit the bill?

They now "outsource" their speakers but still make the Swarm subwoofer mesh:

http://www.audiokinesis.com/the-swarm-subwoofer-system-1.html

https://jamesromeyn.com/audiokinesis-speaker-design/#philosophy

I am aware of AudioKinesis from Audiocircle but I haven't been able to find detailed measurements to verify their performance. Hence, I haven't added them yet. Promising though, with the recognition of multisubs and directivity control. Also one of only two companies I know selling fully-built speakers with the SEOS waveguide.

 

[localhost127]

Because spectrum of the sound will determine its shape as much as its timing. High frequencies have a larger effect than low.

that's not a satisfactory response to be honest - and it's not even related to the proposed question (just a slight-of-hand misdirection??). i had asked: "the ETC is a time-domain measurement. how exactly is the Envelope Time Curve "extremely unreliable measurement" when analyzing the time (and thus corresponding total flight path distance) arrival of indirect specular energy?"

as i stated in my orig reply: "you could have electronic propagation delay (in the soundcard, for example) - but that is appropriately addressed by utilization of a simple loopback. something any competent operator is aware of. "


where exactly did you indicate timing discrepancies or that the actual indirect energy arrival is "extremely unreliable"? both plots you listed show the energy arriving at the same time offset from the direct signal (which could then be used to calculate total reflection distance and thus be traced back to the respective incident boundary). you seem to be showing an example of how to incorrectly use a tool or draw erroneous conclusions from a given graph (a classic case where the operator is not smarter than the tool). just as when someone draws erroneous conclusions solely from viewing the frequency-response. this time you are providing evidence via a "500hz band-limited speech" signal - vs a broadband signal as with home stereo reproduction. my stereo does not solely reproduce 500hz band limited speech signals. analyzing my loudspeaker-room response in 500hz band-limited speech is not applicable to me in any regard.

i have never personally utilized the ETC to hunt down "500hz band-limited speech signals" in any audio reproduction environment. is this something most people do here commonly? is it how you "tune" a room?

i for one analyze and "treat" my room (to my pre-defined requirements) based on the full bandwidth my loudspeaker is radiating into the bounded space - and use the ETC to identify spurious indirect signals that are non-broadband and that Toole explicitly states i should absorb.

The above is not a surprise to anyone with basic understanding of signal processing. But very non-intuitive to people outside of that domain. I suggest not using ETC or advocating it without understanding said science.

the ETC is a great tool to understand the time-arrival of spurious indirect specular energy. especially to hunt down destructive indirect specular reflections that are not broadband (ie, when a loudspeaker does not exhibit controlled dispersion as so many do today - and as Toole recommends to absorb said reflection). even if you have a loudspeaker with good off-axis response (CD), Toole explicitly states it is a matter of taste whether one prefers more pin-point imaging vs broadened (at the expense of accuracy) imaging. so if i personally choose to identify indirect specular reflections and trace them back to their incident boundary (reflection point) where they can be treated, i would do so with time-domain data (thus flight path distance) acquired from the ETC. nothing you provided in your response invalidates this methodology.

the frequency-domain (frequency response) doesn't provide me any information as to how to identify these destructive indirect reflections and how to trace them to their incident boundary and verify they have been attenuated post-treatment. as Toole states, a reflection from a loudspeaker with poor off-axis response should be absorbed/attenuated, and the ETC is a great tool to hunt down these destructive reflections to their incident boundary. the ETC can also be used to hunt down other "non-obvious" sources of indirect energy that must be addressed - vs that of obvious "first-order sidewall reflections".

Dr. Toole says it best after above example:

"All of this is especially relevant in room acoustics because acoustical materials, absorbers, and diffusers routinly modify the spectra of reflected sounds"

this is a classic case of operator-error. using a thin porous absorber is not an effective broadband device and merely "EQ's" or "colors" the reflection, turning it into a LPF. this has been well known and understood in the acoustics world since well before Toole's publishing - and hence why the recommendation for absorbers (when they are chosen to be used) to be of sufficient thickness in order to fully attenuate a broadband signal.

a user applying a thin absorber such as foam or carpet/rugs does not invalidate or qualify your claim that the time-domain information in the ETC is somehow "extremle unreliable".

you seem to be inducing some distraction and "slight-of-hand" to deflect from the proposed question.

I explained all of this to you repeatedly in AVS Forum. Years later you are still repeating lay-intuition nonsense that misleads people into screwing up their rooms, spending a ton of money uglifying them to boot. Spend some time learning the science for heaven's sake.

edit: there's simply no need for personal attacks and false insinuations such as this.

 

[Bjorn]

Toole explicitly states it is a matter of taste whether one prefers more pin-point imaging vs broadened (at the expense of accuracy) imaging.

It's also worth mentioning here that Toole research in this area is clearly limited to the acoustic environments he experimented with. If you have for instance a late lateral diffuse tail in the room, things can change quite dramatically.

Personally I've also found that short listening tests for "preference" or "taste" aren't always reliable. What I prefer over time may be different than what experience after a very short listening interval. While preference is a difficult subject to study, accuracy is a lot more straight forward.

IMO one would be wise to be careful of using the flag of science. Especially in areas where we have various and sometimes even opposite resulting studies (as in several psychoacoustic areas) and were things often depend on other things.

 

[amirm]

IMO one would be wise to be careful of using the flag of science.

What's the alternative? Someone's opinion formed from uncontrolled testing?

 

[amirm]

that's not a satisfactory response to be honest - and it's not even related to the proposed question (just a slight-of-hand misdirection??). i had asked: "the ETC is a time-domain measurement. how exactly is the Envelope Time Curve "extremely unreliable measurement" when analyzing the time (and thus corresponding total flight path distance) arrival of indirect specular energy?"

You jumped into this conversation:

I explained what they issues are in interpreting them. And their usefulness. And the signal processing behind it. As asked by Ray.

You challenged my statement so I explained it again in more detail.

If you are asking simply if you can use ETC for timing detection, which is not what was asked or being discussed, you can. There are dead simple substitutes that don't require ETC such as just looking at the room, using a mirror, tape measure, etc. But if you want to use ETC, is fine. Just don't go to the next sentence as you do that people should assign value to those reflections and go and try to eliminate them all. If you do, then you run foul of what I explained.

 

[amirm]

i have never personally utilized the ETC to hunt down "500hz band-limited speech signals" in any audio reproduction environment.

500 Hz? What was explained was a general issue with ETC because it is spectrum-blind. It says that the spikes in such measurement are not representative of the true energy of the reflections. There is no magic 500 Hz in there. Anything that absorbs some of the spectrum of the reflection will produce such false measures.

i for one analyze and "treat" my room (to my pre-defined requirements) based on the full bandwidth my loudspeaker is radiating into the bounded space - and use the ETC to identify spurious indirect signals that are non-broadband and that Toole explicitly states i should absorb.

You do? In literally years of arguing with you on this topic on AVS, you did not once produce a measurement you had performed. Later on I discovered you lived in an apartment and did not even have an audio system.

And why do you need ETC to know which reflections to absorb? If you are designing a new listening space, how would you do that without measurements? You need ETC to know there is a side wall reflection? Ceiling? Floor? Rear and front walls?

Answer is that you don't. Professional acousticians design state of the art listening spaces all on paper without a single measurement to "find reflections: using ETC or otherwise. We use psychoacoustics research into perceptual effects of reflections and use that a priori to decide what to do with reflections. ETC with its faulty amplitude problems need not apply.

 

[amirm]

as Toole states, a reflection from a loudspeaker with poor off-axis response should be absorbed/attenuated,

No, he says to buy a speaker with proper off-axis response that correlates well with direct sound. If you chase and try to remove all those reflections for a bad speaker, you will build a padded cell that will be dead as a year old fish. It will sound horrible for any 2-channel listening and depending on how far you have gone, for multi-channel as well. You have completely bastardized Dr. Toole's research with that statement.

 

[amirm]

edit: there's simply no need for personal attacks and false insinuations such as this.

Membership here is not familiar with you, your personality and knowledge level. I wanted to make sure they were up to speed that you just repeat stuff you learned from some old text (Davis) which you misread and some random dude online who claimed to know the topic. And that you will grab on someone's pant leg and won't let go with this ETC talk. If none of this is you, then update us so we know.

 

[direstraitsfan98]

@Ilkless and @q3cpma Can you tell me your thoughts on ATC speakers please. What do you think about the actives they sell, the SCM50, 100, AND 150 actives?

 

[Ilkless]

@Ilkless and @q3cpma Can you tell me your thoughts on ATC speakers please. What do you think about the actives they sell, the SCM50, 100, AND 150 actives?

Not much better than Harbeths. The massive brute force motor of the midrange dome means it's footprint is unacceptably large to have an optimal CtC spacing for it's passband. For an example of a good mid dome, see the waveguided dome Neumann uses in the 310 and 420. That has SOTA max SPL and distortion with a much more compact CtC.

 

[direstraitsfan98]

I'm not sure what CtC spacing for the passband means or what you mean by its footprint being too large. Are you saying that the design of the ATC speakers are flawed? That there isn't enough space and/or its too large in size and that it's measurements suffer for it? If you could elaborate please I'd appreciate it. And try to explain what you mean and how it might relate to how they sound in room.

Regarding the active line of speakers I mentioned, the SCM50, 100, and 150, they all have largely the same looking design just a different sized woofer. I don't know anything about speaker design so hearing what flaws and issues they have is new to me.

 

[Koeitje]

What I've seen in terms of measurements from ATC also doesn't inspire much confidence.