A Broad Discussion of Speakers with Major Audio Luminaries

[gnarly]

By definition your room is not an anechoic chamber so it will corrupt the phase and repeatedly so.

Direct sound that is phase and time aligned, reaches the ears as such.
The issue/question of how much reflected sound gets integrated with direct is too situation/room specific to make universal pronouncements about how much phase gets corrupted, or about what we can and can't hear with respect to time and phase alignment.

I know it doesn't take an anechoic chamber to help separate direct from reflected, to get a handle of the value of phase and time alignment. Constant directivity speakers with a defined narrow pattern help, especially in a larger room.
Outdoors really helps/works, and ime, can make you think twice about the "value and appeal" of reflected sound... (per widely accepted/quoted research).

btw, fun short vid about the sound of a balloon pop.... outdoors, different rooms, and an anechoic chamber at the end.
Outdoors clearly is a long way from sound sucking anechoic..

edit: grammar

 

[Arindal]

differences can be heard (the phenomenon is "real") but preferences are not statistically reliable (the phenomenon is common in everyday life, and it is at least somewhat normalized).

Particularly true to completely artificial sounds such as bassdrum sounds of EDM, electric guitars or close-mic´d vocals of popular recordings. I would not find it useful to ask listeners for their overall subjective preference in this case, as there are inevitably too many variables. Risk is IMHO high in this case that listeners might not like a specific aspect of the recording - like narrow ´mono bird on the wire´ phantom localization - and prefer any setup that is reversing these aspects, for example by creating artificial, enveloping reverb or blurring the localization.

If you ask the mixing engineers or masterers, that might make more sense, or if you narrow down the preference questions to very specific aspects such as ´which variant has the lowest/tightest/fastest/most precise bass?´, ´which shows the least broad/most stable phantom source localization?´. I found the answers to be usually pretty coherent in this case.

We live in rooms and reflected sound is part of everything we hear, even conversing across a table distorts the amplitude and phase of voice sounds, ever changing as we move around, leaning forward or back, standing, sitting, etc. Measurements indicate horrendous acoustical interference effects - amplitude and phase variations - but we are not conscious of any of them.

Agreed to the acoustic reality, but usually there is a point at which this or that acoustic phenomenon in a room is deteriorating aspects of sound quality, bringing it closer to an annoying or at least recognizable flaw. Unsharp/unstable localization comes to mind, dull reverb, harsh or aggressive brilliant consonants, bass which is restricted in lower cutoff frequency, or boomy, bloated or slowly decaying bass. If you give people proper samples for a test and ask a specific question, I would expect them to give similarly coherent answers.

 

[levimax]

If that fix comes for free, why not.

Getting the last two octaves "correct" in a small domestic room is anything but "free". It takes multiple large and expensive speakers and powerful electronics and the room itself needs to be able to handle high SPL LF sound without banging and rattling so the room may have to be rebuilt from the studs up (this is in addition to any "room treatments"). So up until now the common wisdom has been that the "monetary costs" and limited available of material have not been worth the small potential SQ advantages. Not worth it is not the same as does not matter or is not audible. As mentioned there is more music with LF content now than in the past and technology both for playback and recording has improved so the "cost/benefits" equation may be changing. Of course for a "serious / obsessed" hobbyist the "cost/benefits" equation is entirely different than for the Hi-Fi mass market.

 

[Fidji]

Getting the last two octaves "correct" in a small domestic room is anything but "free". It takes multiple large and expensive speakers and powerful electronics and the room itself needs to be able to handle high SPL LF sound without banging and rattling so the room may have to be rebuilt from the studs up (this is in addition to any "room treatments"). So up until now the common wisdom has been that the "monetary costs" and limited available of material have not been worth the small potential SQ advantages. Not worth it is not the same as does not matter or is not audible. As mentioned there is more music with LF content now than in the past and technology both for playback and recording has improved so the "cost/benefits" equation may be changing. Of course for a "serious / obsessed" hobbyist the "cost/benefits" equation is entirely different than for the Hi-Fi mass market.

Having low quality bass is a choice today. Since some time there are lot of available options - SBA, DBA, Waveforming, ART, that that take room out of equation in LF.
There are clear audible and measurable benefits of using those more sophisticated ways vs “good ol’EQ”. Good Group Delay vs so-so GD from the past [and from less efficient DRC systems] brings higher level of accuracy to the timbre on bass heavy instruments.

Also modern DSP [Dirac, Optimizer, Re-phase and many others] do correct phase response on top of amplitude corrections. While “do not touch EQ above 500Hz” mantra was probably justified 20 years ago, now it is outdated.

 

[markstein]

Also modern DSP [Dirac, Optimizer, Re-phase and many others] do correct phase response on top of amplitude corrections. While “do not touch EQ above 500Hz” mantra was probably justified 20 years ago, now it is outdated.

I disagree. Some thoughtful manual broad EQ above Schroeder may be beneficial to slightly adjust spectral balance in certain rooms - however I never liked automatic EQ by e.g. Dirac or Acourate (do not know other solutions). Given the way human hearing works vs how a monaural measuring mic works this is no surprise...

 

[krabapple]

Having low quality bass is a choice today. Since some time there are lot of available options - SBA, DBA, Waveforming, ART, that that take room out of equation in LF.
There are clear audible and measurable benefits of using those more sophisticated ways vs “good ol’EQ”. Good Group Delay vs so-so GD from the past [and from less efficient DRC systems] brings higher level of accuracy to the timbre on bass heavy instruments.

Also modern DSP [Dirac, Optimizer, Re-phase and many others] do correct phase response on top of amplitude corrections. While “do not touch EQ above 500Hz” mantra was probably justified 20 years ago, now it is outdated.

That 'mantra' applied to speakers that are well designed and performed well in a Klippel/anaechoic chamber, and still does.

 

[RickS]

Having low quality bass is a choice today. Since some time there are lot of available options - SBA, DBA, Waveforming, ART, that that take room out of equation in LF.
There are clear audible and measurable benefits of using those more sophisticated ways vs “good ol’EQ”. Good Group Delay vs so-so GD from the past [and from less efficient DRC systems] brings higher level of accuracy to the timbre on bass heavy instruments.

Also modern DSP [Dirac, Optimizer, Re-phase and many others] do correct phase response on top of amplitude corrections. While “do not touch EQ above 500Hz” mantra was probably justified 20 years ago, now it is outdated.

Just to be sure, suggest you meant “quality low bass” rather than “low quality bass”.

 

[amirm]

Direct sound that is phase and time aligned, reaches the ears as such.

Direct sound doesn't happen in an infinitesimally small time period. Reflections from milliseconds before in time are mixing with it, albeit at lower amplitude. Only in anechoic chamber what you say is true. This is the very basis of the impact of room on sound. You are imagining something that doesn't exist in real rooms. Specialized signals attempt to lower the possibility of this happening and hence the higher probability of it being audible.

 

[andyc56]

That 'mantra' applied to speakers that are well designed and performed well in a Klippel/anaechoic chamber, and still does.

Exactly. "Don't equalize above the Schroeder frequency" is sometimes used as a borderline strawman argument.

For instance, in Floyd Toole's original 1986 article "Loudspeaker Measurements and Their Relationship to Listener Preferences: Part 2" article, he cautions against equalizing the room curve (smoothed steady-state on-axis measurement) of Loudspeaker 7 to a target. Loudspeaker 7 of that article had flat on-axis anechoic response, but a strange-looking room curve because of its substandard directional characteristics. He points out that equalizing the room curve of this loudspeaker to a target will mess up the only good thing about it: the flat on-axis anechoic response. I'm sure you know this, but others may not.

But there can be loudspeakers with mediocre on-axis anechoic response but very good directional characteristics. Some spinorama measurements were done on a DIY Sound Group speaker (I can't remember the exact one), and it showed just such a property. Doing an equalization of the on-axis quasi-anechoic response of such a speaker to flat has merit.

 

[Duke]

Direct sound doesn't happen in an infinitesimally small time period. Reflections from milliseconds before [sic] in time are mixing with it, albeit at lower amplitude. Only in anechoic chamber what you say is true. This is the very basis of the impact of room on sound.

Did you mean to say "Reflections from milliseconds later in time are mixing with it, albeit at lower amplitude"?

I can see how this would be true for early ipsilateral (same-side) reflections because they arrive at that side's eardrum conflated with the direct sound.

But for early contralateral reflections, which arrive at the opposite ear from the first-arrival sound, wouldn't the ear's binaural processing ability allow it to distinguish the reflections from the direct sound?

 

[Fidji]

That 'mantra' applied to speakers that are well designed and performed well in a Klippel/anaechoic chamber, and still does.

I am yet to hear “perfect” speaker in “perfect” room. Also those that scored very high here and in spinoramas can be improved by applying appropriate corrections. One of the reasons might be catering to personal preferences and to adjust to room interactions. E.g. my Neumanns greatly benefit from adding approx 1db between 400 - 700Hz and slight attenuation in 3-5kHz range. Makes acoustics instruments, that I use as reference sound more correct.

So it is more choice about being content with “good enough” vs trying to squeeze out last couple of % of speakers potential. But I am in no disagreement with basic principle - you will not EQ horrible speaker into great one. But you can EQ well engineered speakers, also above Schroeders frequency.

Just to be sure, suggest you meant “quality low bass” rather than “low quality bass”.

No, I really meant “low quality” as bad. There are so many ways to get good bass, that staying with bad bass is a choice. Like knowing about health effects of ultra-processed food and still keeping eating it.

 

[sigbergaudio]

I am yet to hear “perfect” speaker in “perfect” room. Also those that scored very high here and in spinoramas can be improved by applying appropriate corrections. One of the reasons might be catering to personal preferences and to adjust to room interactions. E.g. my Neumanns greatly benefit from adding approx 1db between 400 - 700Hz and slight attenuation in 3-5kHz range. Makes acoustics instruments, that I use as reference sound more correct.

But this isn't typically what automatic correction does. Those systems flatten out the measured response (often according to some target), and quite aggressively so.

 

[Fidji]

But this isn't typically what automatic correction does. Those systems flatten out the measured response (often according to some target), and quite aggressively so.

I was never talking about automatic corrections. I was talking about corrections above Schroeders frequency.

 

[gnarly]

Direct sound doesn't happen in an infinitesimally small time period. Reflections from milliseconds before in time are mixing with it, albeit at lower amplitude. Only in anechoic chamber what you say is true. This is the very basis of the impact of room on sound. You are imagining something that doesn't exist in real rooms. Specialized signals attempt to lower the possibility of this happening and hence the higher probability of it being audible.

How can reflections from milliseconds before in in time arrive before a straight-line path from the speakers? Hyperjump via warp drive? Lol

I mentioned ways to hear higher direct to reflected, which also concomitantly lengthen the reflection-free time window of the direct arrival.
Higher directivity, large rooms. Said outdoors works. I do a great deal of outdoor listening and measuring just for this purpose of hearing direct as cleanly as possible..

My favorite outdoor listening test, is when I put a speaker up high, pointing down towards the lake. Then I float in the lake with head only out of the water, ....and listen.
Even floor bounce mainly disappears. Simply wow.

So sorry, I'm not imaging anything. I test too much in too many ways. It simply doesn't take an anechoic chamber to hear direct much better before reflections fuse in, than in a small room.

I do wish folks would view audio science as a bigger subject than that of dealing with small rooms.
Home audio is just a subset of audio.

 

[sigbergaudio]

I was never talking about automatic corrections. I was talking about corrections above Schroeders frequency.

Hm. You said "Also modern DSP [Dirac, Optimizer, Re-phase and many others] do correct phase response on top of amplitude corrections. While “do not touch EQ above 500Hz” mantra was probably justified 20 years ago, now it is outdated."

Sounded like you were referring to automatic corrections here? Or no?

 

[Suono]

The sound of an instrument is by definition in phase; two microphones will pick it up, and the speakers will reproduce it. If we're talking about high fidelity, I wonder why it could be negligible, or even unimportant, for the speakers to be phase-coherent? The room has nothing to do with it. The room comes later.

 

[Fidji]

Hm. You said "Also modern DSP [Dirac, Optimizer, Re-phase and many others] do correct phase response on top of amplitude corrections. While “do not touch EQ above 500Hz” mantra was probably justified 20 years ago, now it is outdated."

Sounded like you were referring to automatic corrections here? Or no?

I used some well known systems to make a point about phase correction vs pure EQ. We can have discussion e.g. how automatic e.g Trinnov Optimizer or Re-Phase is. Not that automatic, or at least gives options to heavily adjust the result. Similar to Dirac on Storm.

 

[NTK]

The sound of an instrument is by definition in phase; two microphones will pick it up, and the speakers will reproduce it. If we're talking about high fidelity, I wonder why it could be negligible, or even unimportant, for the speakers to be phase-coherent? The room has nothing to do with it. The room comes later.

Two microphones? Since any music with more than one sound producing sources (e.g. a musician singing and playing the guitar) is not a point source, so it is impossible for the microphones to be equi-distance to all sound sources, so there went your phase coherency.

And microphones are linear phase?

 

[Keith_W]

How can reflections from milliseconds before in in time arrive before a straight-line path from the speakers? Hyperjump via warp drive? Lol

I think he was talking about music, rather than test signals. So yes you can get reflections from the previous transient contaminating the current transient. It think he worded it a bit clumsily hence the confusion.

 

[krabapple]

I am yet to hear “perfect” speaker in “perfect” room.

Which of course was not the stipulation.

I suggest you engage Dr. Toole, if this is the hill you want to battle on.