Quantifying an "Open Sound"

[Euler]

Users often describe the Super HL5 as having a magical "open sound". Given everything he's learned from using software to redesign the C7, 40, and P3, Alan recently worried about "over-engineering" a speaker design, an unintended consequence being the loss of "magic". What do we mean by an "open sound"?

Can we measure it? If we can quantify this magic, then perhaps one could prevent its disappearance during a redesign.

Bruce

[garmtz]

Unfortunately, an 'open' or 'transparent' sound cannot be measured, but it can be appreciated very easily. It enables you to look 'into' the recording, like the curtains have been lifted from the speakers. The amazing thing with a Harbeth speaker is that this transparency can be enjoyed even at very low playback levels.

The loss of 'magic' is also totally unmeasurable. How do you describe beauty? It must be experienced by a human being. Most things can be measured, but the design of a Harbeth is part science, part listening. It is in the listening that this 'magic' can be detected.

So unfortunately (well, according to my insights), neither an 'open sound' nor 'magic' can be measured. If we could measure beauty and magic, than we could 'engineer' great music/art. It just doesn't work like that.

Having said that, I have heard many speakers that technically sound perfect, but ultimately lack 'soul' and 'beauty'. Harbeth delivers this in spades.

[Pluto]

Primarily, I would argue, lack of colouration in the low and mid-ranges, particularly in the human voice region of the spectrum.

I never tire of saying, "listen to speech"! Particularly, male speech that must, obviously, be well recorded. Listen to it at a realistic level and ask yourself a simple question - does the reproduced sound actually approach the realism of the genuine article which we hear every day and can, therefore, judge with relative ease.

A very simple test, but one which causes many so-called hi-fi installations to fall at the first hurdle.

[Euler]

Primarily, I would argue, lack of colouration in the low and mid-ranges, particularly in the human voice region of the spectrum.

I never tire of saying, "listen to speech"! Particularly, male speech that must, obviously, be well recorded. Listen to it at a realistic level and ask yourself a simple question - does the reproduced sound actually approach the realism of the genuine article which we hear every day and can, therefore, judge with relative ease.

A very simple test, but one which causes many so-called hi-fi installations to fall at the first hurdle.

Perhaps the accurate reproduction of human speech is, as you suggest, primarily responsible for this "open sound," but it seems to me there must be some other significant thing going on, for otherwise one might expect other Harbeth speakers, like the C7ES3, which, to my ear, reproduces speech with extraordinary fidelity, to be described as having an "open sound" just as often as the SHL5. Yet that does not seem to be the case. In the Harbeth line, the SHL5, and the SHL5 in particular, is often described as having an "open sound."

I like magic as much as the next fellow, but if golden ear Harbeth users agree on the particular open sound of the SHL5, then maybe there's a real difference, and that difference would have a source, a physical, not a magical, source -- cross-over, cabinet dimensions, whatever -- and that source could, in principle, be tracked down.

Bruce

[garmtz]

I do not agree that the SHL5 has more of an 'open sound' than any other Harbeth speaker. In fact, I find the Monitor 30 to be more open still (in the midrange).

[Euler]

I do not agree that the SHL5 has more of an 'open sound' than any other Harbeth speaker. In fact, I find the Monitor 30 to be more open still (in the midrange).

I did not claim that the SHL5 has a more open sound, but rather that the SHL5, more than other speakers in the Harbeth line, is often described by those who've heard it as having an open sound. You, a single individual, might not agree with this general assessment, which is fine.

In any case, my questions remain the same: What do we mean by an "open sound." And can we figure out why, in the engineering sense, a particular speaker design might be so described?

Bruce

[Gan CK]

For me, anything that is not muffled, muddy, boxy or shut in qualifies as being open sounding. Most modern day spks are sufficiently open. The degree of openness varies from spk to spk. Many spks however resort to a forward & or bright presentation to give the impression of sounding open & to mask a lack of transparency in the midband.

To me, all Harbeth spks are very open sounding & transparent without resorting to a forward & bright/sharp presentation. Such is the inherent quality of the Radial cone driver. And as Garmtz mentioned above, they deliver soul & beauty in spades.

[STHLS5]

Excellent thread! We have different individuals describing "open" terminology in relation to speakers' sound in their own way.

Unfortunately, an 'open' or 'transparent' sound cannot be measured, but it can be appreciated very easily. It enables you to look 'into' the recording, like the curtains have been lifted from the speakers.

Some of my reference recordings made directly without any amplification sound flat to my ears.

Primarily, I would argue, lack of colouration in the low and mid-ranges, particularly in the human voice region of the spectrum.

A male voice is said to be within 85 to 180Hz. So speakers with limited frequency range to be considered as more open than a full range speaker?

For me, anything that is not muffled, muddy, boxy or shut in qualifies as being open sounding.

You have described the definition of a perfect speaker. So that means only a perfect speaker is an open sounding speaker? Everyday, I pass a music shop and somehow the sound from the Peavey speakers sounding more open than my system. Though I hate the high treble sound of the speakers.

And the Stereophile's definition -

Exhibiting qualities of delicacy, air, and fine detail. Giving an impression of having no upper-frequency limit.

Having no upper-frequencies limit certainly qualifies the SHL5 with the super tweeters to be more open sounding than other Harbeth speakers.

Whatever is it, it appears, we all have certain preconceived idea of sound that may well be very different to another. It is also common knowledge among recording engineers to increase the frequencies above 10kHz to add air to vocals. The term air or airy is usually associated with open sounding. That's not original but it adds a flavour to the vocals.

The best is to let our ears to judge what's best.

ST

[garmtz]

Some of my reference recordings made directly without any amplification sound flat to my ears.

What do you exactly mean with this?

[STHLS5]

What do you exactly mean with this?

When I said live unamplified sound, I meant sound without amplification, EQ and other digital tricks that often employed to improve a recording. Perhaps, the examples of sound clips found here may convey my message more clearly. (Try Setting 3)

I agree when you said that an open sound means you should be able to look into the recording, like the curtains have been lifted from the speakers but which of the sounds in the above clips sound transparent? And which one sounds open? Does natural sound open or openness is just an illusion like depth?

ST

{Moderator's comment: I wonder, did Alan cover this with sound examples in his thoughts about recording studio acoustics a while back?}

[A.S.]

Now this really is an interesting thread.

Are we saying that, despite the fact that we here are all bonded by a common appreciation of 'natural sound', that we cannot define it? May I suggest that we at least try and narrow the field to say what natural sound is not. That may help us to define what it actually is. May I kick this off?

I'd say that 'natural sound' reproduced over a quality audio system will not be ....

1) Fatiguing
2) Too loud

(This is more difficult than it looks!)

[STHLS5]

What actually isn't 'natural sound' then?

What makes piano sound to be natural? Or a*flute? An acoustic guitar? How can a piano be natural when there is no piano tone in nature? Listen to the nature, listen to the songs of birds, whales or even the howling wolves. Do you hear anything that resemble a piano or any of the musical instruments? Perhaps, with an exemption to the sound of a flute most musical instruments sound is not reproduce by mother nature.

That leaves us with our voice as a sole reference to natural sound which "supposedly" can be reproduced by playback devices. But in reality to reproduce a vocal we need a suitable microphone. Now, isn't human voice is within 80 to 1000Hz? I am giving a much wider range since some singer capable going above the upper limit of 250 or so Hertz. *So why is it we need a special microphone for vocals. To complicate the matter further some microphones suit some singer better than others. There goes my reference again. If I were to record my voice with a *Nuemann and later I discover that Shure really suits my voice then I am without an absolute reference prior to that.


ST

[A.S.]

Wait. That's going in far too deep too soon, IMHO. We are just never going to progress this unless we concentrate on the core points. Let's just take this nice and easy and carefully examine your very astute opening comment ....

What makes piano sound [to be] natural?

Well, what do me make of that valid question?

[STHLS5]

The answer is best answered by quoting you...

You know, the piano has a similar characteristic to the human voice. I think that is why it is such a universally loved instrument - it 'talks' to us with a voice and soul just like a human. Reproducing human voice - and hence the piano accurately is by far the most difficult task for a loudspeaker. That's because we all know how a real live human sounds, and many of us know how a live piano sounds too. No degree-level acoustics expertise needed to hear and judge a great piano in action

But then which piano sound is accurate and natural? Compact7 was developed based on the bright tones of Steinway. So is Steinway is more natural than a Yamaha?

ST

[garmtz]

This thread started with the question how to quantify/qualify an 'open sound'. Is a 'natural' sound always an open sound? Or the other way around, is an 'open' sound always 'natural'? I think the first is true, because 'not open' will always point in the direction of some colouration, either subtractive or addictive. As for an 'open' sound to be natural: many people do not know what 'natural' is, because they are missing some point of reference. Many speaker manufacturers make advantage of this by emphasizing the highs/mids to some extent, giving the IMPRESSION of 'opennes', while in fact, it is simply another colouration. Most of these manufacturers would do this to mask the fact that the speaker isn't really open sounding in the first place.

This has all been said in this topic, but I think it is a good starting point to first define the word 'open'. What makes a speaker sound 'open'? Is it low level detail, lack of colouration? A linear frequency response? I think this will asnwer the question of the topic starter best. Maybe we can open another topic to investigate what constitutes 'natural sound'?

[EricW]

Well, what do we make of that valid question?

Well, pianos do exist as physical objects in the real world, and they are capable of making sound without amplification. (True, no two are exactly alike, but then, no two voices are exactly alike either.) Virtually everyone has heard an unamplified piano and has a fairly good idea what one sounds like.

So, in very simple terms, I'd say a "natural" piano sound is a recording that conveys as much as possible the sound that makes a piano a piano, and not some other instrument.

Too simple?

[Euler]

I'd say that 'natural sound' reproduced over a quality audio system will not be ....

1) Fatiguing
2) Too loud

(This is more difficult than it looks!)

I wonder whether the sound of the chicks in the nest of Great Tits might be very "natural" through Harbeth speakers, yet still fatiguing.

Bruce

[A.S.]

...But then which piano sound is accurate and natural? Compact7 was developed based on the bright tones of Steinway. So is Steinway is more natural than a Yamaha?

Thanks for the quote but to the casual reader it could be misinterpreted as meaning that somehow the C7 was optimised in such a way that it enhanced the Steinway at the expense of the Yamaha. And that's definitely not true; it's not my job to design a speaker that has a strong sonic personality that could favour one istrument over another.

The key question surely has to be this: One cannot begin the process of appraising what is 'natural sounding' unless you have some reliable, memorable experience of hearing a particular instrument (or at the very least, a class of instrument) in the raw, unamplified with your own ears and with enough time to concentrate on the sound and absorb and commit the experience (or at least, the ghost of the memory of the flavour of the experience) to long term memory.

So, what I was commenting on was, heard 'in the flesh', how much brighter and interesting the tone of the Steinway was than I imagined it to be. Whether you like the Steinway sound is of course entirely a matter of choice. But it's certainly very difficult for any speaker system to capture that air.

[Euler]

This thread started with the question how to quantify/qualify an 'open sound'. Is a 'natural' sound always an open sound? Or the other way around, is an 'open' sound always 'natural'?

[snip]

What makes a speaker sound 'open'? Is it low level detail, lack of colouration? A linear frequency response? I think this will asnwer the question of the topic starter best. Maybe we can open another topic to investigate what constitutes 'natural sound'?

Yes, if "open sound" and "natural sound" are different, then we have two different questions. My original question -- What do we mean by an "open sound" and can one track it down, in an engineering sense, to a source? -- was prompted by Alan's worry that, driven by all the knowledge he has gained over the years, he might inadvertantly end up engineering the "magic" (which might be the "open sound") out of given speaker in its redesign.

Bruce

[A.S.]

I'm wondering is this 'openness' is related to frequency response. Perhaps in the loudness of particular frequency bands or to the extension of the overall bandwidth at the extremities.

We've looked at this sort of concept in very great depth in this thread.

In particular, going directly to post #62, we can hear examples of the manipulation of the frequency response. Also have a look at posts # 63 and more examples in post #64.

Are we still floundering or can we perhaps eliminate frequency response as a factor in 'openness' I wonder and move onwards. Or perhaps not? But we do need to run this one to ground.