What's Left In Speaker Design To Reduce Distortion/Increase Detail Retrieval?

[MAB]

Enjoy your Genelecs. (Or whatever you own).

By the way, I actually have a pair of speakers with the same Seas Excel tweeter as your Perspectives, and the larger Excel midbass.

Active DSP DIY speakers, for testing a few ideas

FFLOTSAM (Fabricated From LeftOver Things Studio Active Monitor) Active DSP speakers, for testing a few ideas I had some stuff lying around; a few random Baltic Birch-ply panels, some countertop material, a few cans of partially used brown spray paint, and some not-too clumpy spar varnish (that...

www.audiosciencereview.com

The drivers started as a DIY I built 20 years ago, called Thor by Joeseph D'Appolito. I modified the speakers over and over, building a larger transmission line, changing crossover, etc.
I then went active, using a pair of crossover boards I hacked from Siegfried Linkwitz for one of his DIY designs.
Then I got a MiniDSP digital crossover. I have several of those over the years now, they are incredibly useful.
I later built the drivers into a pair of 2.5-ways with the same midbass as your Perspectives combined with the larger Excel woofer. The idea was they would be smaller than the mighty Thor, but not really in the end.
I ended up samples of most of the Seas Excel line. They are really great, if not totally contemporary. Like the tweeter is truly awesome, but lacks the modern waveguide and needs care in matching directivity. The midbass have all sorts of resonance above the passband (you can read about it in the build thread), these have to be controlled or need to have an absurdly low crossover to the tweeter or be used 3-way.
And I really enjoy them in the latest incarnation.
I have a beautiful pair of classic Rauna, made from concrete, called Swedish Tombstones at some point.
A few Paradigm, including some of the classic Studio Monitors.
etc.
And yes, a pair of Genelec ones. Which I also love.

 

[JohnBooty]

I understand. For whatever reason, sometimes an elevated treble can drive me nuts, in other designs not so much. I presume that it will often come down to the specific balance struck by the speaker (e.g. some richness in the lower frequencies can make slightly goosed higher frequencies more palatable.

That's interesting. I hadn't thought of that possibility. I'd always kind of assumed that it was a matter of whether or not the elevated treble had a smooth rather than jagged response.

 

[teashea]

That's interesting. I hadn't thought of that possibility. I'd always kind of assumed that it was a matter of whether or not the elevated treble had a smooth rather than jagged response.

I do not know what richness in lower frequencies means. Personally I like a completely flat frequency response. That is what Neumann does, which is why I chose their monitors.

 

[MattHooper]

I do not know what richness in lower frequencies means. Personally I like a completely flat frequency response. That is what Neumann does, which is why I chose their monitors.

Just curious: are you a native English speaker?

Take two loudspeakers and one was described as sounding lean in the base and the other is sounding much richer in the base, would you have no idea what that might be alluding to?

 

[teashea]

Since this is a scientifically oriented site, words such as those are imprecise and not very helpful. Do you want a speaker where the bass is exaggerated instead of flat? The best speaker designers strive for a flat frequency response.

 

[MattHooper]

Since this is a scientifically oriented site, words such as those are imprecise and not very helpful.

Ok. I was just wondering. Because it's one thing to want measurements because they are more precise; it's another to not have any clue what a subjective description would
mean.

Do you want a speaker where the bass is exaggerated instead of flat?

Possibly. Lots of people like that. I tend to like tight bass, but don't mind a little extra midbass kick, or lower bass boost. As long as it doesn't sound obviously exaggerated to me.

The best speaker designers strive for a flat frequency response.

I understand seeking flat frequency response. Some speaker designers do a house sound, some customers love that, but I understand that wouldn't fit your criteria for best practices.

 

[JohnBooty]

Just curious: are you a native English speaker?

Take two loudspeakers and one was described as sounding lean in the base and the other is sounding much richer in the base, would you have no idea what that might be alluding to?

What did you mean by "richness?" Boosted bass response? Accurate bass? Deep bass extension? I called your theory "interesting" sort of reflexively because I hadn't considered that something outside of the treble might affect subjective enjoyment of the treble. But, I didn't know exactly what you were describing.

I am a native English speaker.

 

[garyrc]

Since this is a scientifically oriented site, words such as those are imprecise and not very helpful. Do you want a speaker where the bass is exaggerated instead of flat? The best speaker designers strive for a flat frequency response.

IMHO, the best speaker designs would have flat frequency response, if, and only if, the recordings we buy were any way near flat. I prefer highly adaptable speakers, flat or not. If the bass has been rolled off at the recording studio (often the case in the loudness wars) I want a speaker that will take bass boost from my tone controls ("The horror, the horror!") gracefully, without becoming objectionably distorted, blurred, or "untight." If the treble is attenuated, I want to be able to turn it up without harshness. Or, if the treble has been boosted beyond belief (as in the sound for the Smile Box version of How the West Was Won), I like to be able to turn it down and have it remain crisp and clear. I like dynamics that may be beyond the ability of some speakers that happen to be flat, and I like clean, detailed microdynamics, regardless of how the tone controls are set.

For those who demaster the recordings they own, see below, and The Missing Octaves by Chris A on the Klipsch forum (source of the data below). For demastering like this, one would need adaptable speakers. I'm not saying that there aren't some flat speakers that will take quite a bit of EQ without problems; I'm just saying that I would rather have speakers that I could kick around with EQ, without degredation, than ones that are mearly flat.

This:

Becomes this:

 

[JohnBooty]

IMHO, the best speaker designs would have flat frequency response, if, and only if, the recordings we buy were any way near flat.

Can you elaborate on what you mean?

What would be the specific objective qualities of a speaker that "that will take quite a bit of EQ?"

In general, you want plenty of headroom in the system as a whole when EQ'ing. And speakers with a flat or at least smooth frequency response are much easier to EQ. But it seems like that's not what you mean?

I want a speaker that will take bass boost from my tone controls ("The horror, the horror!") gracefully, without becoming objectionably distorted, blurred, or "untight."

What does this mean on an objective level? The speaker doesn't know or care if the bass is added from your tone control, if it's from the original recording, or if you have plugged some sort of artificial bass tone generator into the amp. The speaker can produce bass (or not) at a specific amplitude at a specific frequency with a specific amount of distortion. There is nothing special about bass added from your tone controls.

 

[Curvature]

What's flat frequency response for a speaker? They radiate in all directions.

It's a stupid phrase that doesn't make sense other than if you're talking about some specific curve, which should be specified.

 

[MattHooper]

What did you mean by "richness?" Boosted bass response? Accurate bass? Deep bass extension? I called your theory "interesting" sort of reflexively because I hadn't considered that something outside of the treble might affect subjective enjoyment of the treble. But, I didn't know exactly what you were describing.

I am a native English speaker.

I'd say "Rich bass" is certainly not very specific, and it would need context to help. By itself it tells me the bass response is likely somewhat prominent somewhere in the frequency response. And if someone says one speakers sounds lean in the bass, the other rich in the bass, that suggests to me one will have more pronounced bass over the other. Exactly where that is in the frequency response would have to be narrowed down by further description or context (or measurements).

Here's a typical use of the term, with context given by measurements, a quote from a Stereophile review of the Verity Audio speakers, JA in the measurement section:

"The shelved-down lower midrange is evident, as is a significant midbass peak. This peak to some extent will be due to the nearfield measurement technique, but the combination of peak and dip is responsible, I'm sure, for Mikey's finding the Sarastro's bass to be both "prodigious" but also "somewhat rich and ripe" and "underdamped." That he found the bass tuning more acceptable at low levels is due to this balance mimicking the so-called "loudness" contour."

 

[JaapD]

I think the main missing aspect in speaker design is the missing feedback loop, controlling distortion between the mechanical cone excursion and the input voltage. Apart from a few Motional Feedback designs nearly all current speaker designs have an uncontrolled forward loop only.

Alternatively, you could model the speakers’ behavior and apply corrections through DSP. This seems to be less optimal (or challenging in case of multi-dimensional corrections, linearizing over frequency and amplitude) however comparing it against implementing a motion sensor in the speaker cone and adding feedback electronics is also an aspect open for discussion.



Cheers,

JaapD.

 

[holdingpants01]

I do not know what richness in lower frequencies means. Personally I like a completely flat frequency response. That is what Neumann does, which is why I chose their monitors.

Is it possible for you to show measurements made at your listening position? Conventional designs, not wall mounted are usually as far from completely flat in rooms as it gets, especially when there are no multiple subwoofers involved.
To answer the OP question, I think the way the speakers interact and fight with the room is the next frontier. Flat anechoic response down to 20Hz is meaningless inside the room, especially in a standmount speaker. SBIR will destroy any flatness in the low end and reflections will take care of the rest. Genelec W371/8381, D&D 8C, Kii Audio, B&O are really pushing things forward on the high end side with cardioid responses lower and lower and with added room correction, and all these smaller iK Multimedia MTM, KH80 DSP, Genelec 83x0, Adam Audio with Sonarworks built in etc. on the lower end with their obvious limitations.
The bad news for hi-fi crowd is all of it requires active digital designs which aren't that popular there

 

[teashea]

That is an excellent example of the anthesis of what Audio Science Review is all about. Vague, meaningless, amorphous descriptions instead of measurements and reality.

 

[MattHooper]

That is an excellent example of the anthesis of what Audio Science Review is all about. Vague, meaningless, amorphous descriptions instead of measurements and reality.

?

 

[mhardy6647]

Take two loudspeakers and one was described as sounding lean in the base and the other is sounding much richer in the base

base?

 

[fpitas]

base?

Make your time!

 

[mhardy6647]

Rich bass

 

[garyrc]

Can you elaborate on what you mean?

What would be the specific objective qualities of a speaker that "that will take quite a bit of EQ?"

In general, you want plenty of headroom in the system as a whole when EQ'ing. And speakers with a flat or at least smooth frequency response are much easier to EQ. But it seems like that's not what you mean?



What does this mean on an objective level? The speaker doesn't know or care if the bass is added from your tone control, if it's from the original recording, or if you have plugged some sort of artificial bass tone generator into the amp. The speaker can produce bass (or not) at a specific amplitude at a specific frequency with a specific amount of distortion. There is nothing special about bass added from your tone controls.

I guess this is what I mean:

Down with (max) X-max! And, to echo J. Gordon Holt, Down with [so called] flat!

1. Some speakers (e.g. well designed horn loaded ones) have (and only need) very little excursion (~~1/16") to produce very strong bass, down to about 30 Hz, with very little modulation distortion, but the bass still might be slightly attenuated below, say, 100 Hz. And, contrary to the myth of flat recordings, the recording itself may well have attenuated bass (in digital, to allow a higher recording level for purposes of the loudness wars or other aberrations of the suits, or with vinyl to make space for bass to do justice to Beethoven, Mahler, or Stravinsky). Way back in about 1974, we callow fellows found, that on the average, our bass controls were set to about +2 (~~"2 o'clock") for most records. On my old McIntosh C28 preamp that was about plus 8 dB. Those of us who were horny, with JBL C34s, JBL C55s, Klipschorns, or EV Patricians, or home brew horns found bass EQ worked well, but sometimes needed to be on the order of 10 - 12 dB, with no perceived added distortion. Those who had AR-3As, KLH bookshelf, ADC, Bose 901, etc., experienced added distortion. I imagine that the upper bass and lower midrange notes were being given the Doppler ride of their little lives, plus reduced headroom. With the aforementioned inefficient speakers, one would need 1,500 watts to equal about 75 watts into a typical fully horn loaded speaker, particularly with all that bass boost. Nowadays, one can use room/speaker correction (Audyssey, Dirac, Trinnov) with the tone controls used to touch up the EQ, adjusting it to each separate recording.
2. Below about 40 Hz one can use a subwoofer; one of those horn loaded ones that are about 8 feet tall might be best, but some of us have to limp along with a conventional one.

Here is some data on distortion at high volume, 105 dB @ 14 feet (THX fs), especially IM in speakers, gathered in 1990 -- 2004

Klipschorn 1.7% IM, Slightly Audible 0.25% THD

AR 98RS 2.7% IM Clearly Audible ~3% THD

Fried
Studio 4 10% IM Clearly Audible 4% THD

Platinum
Studio 2 7% IM Clearly Audible 1.9% THD

[From reviews by Heyser, Keele, Jr., and others].

Doppler (modulation) distortion; an excerpt from Stereophile …

“The results were intriguing. Distortion of the flute was gross at 10mm peak diaphragm displacement and not in the least bit euphonic. On the contrary, Doppler made the sound as harsh as you might expect of a distortion mechanism that introduces intermodulation products.

Music signals are less revealing of Doppler distortion than this special brew. But these findings undermine the view, widely accepted in the last two decades, that Doppler distortion in loudspeakers is not something we should trouble about. Having done the listening, I side with Moir and Klipsch more than with Fryer, Allison, and Villchur on this issue—something that may come as no surprise to anyone who has heard the effects of low-level jitter and sees where the Fryer criterion appears in fig.2. .

It has often been claimed that, with a two-way speaker, there are audible benefits to using a crossover frequency below the typical 3kHz, the usual explanation being that this removes the crossover from the ear's area of greatest sensitivity. But I wonder. Perhaps this not-uncommon experience Everyone who uses a two-way speaker (me included) can take heart from the fact that most actually has much more to do with the D word. A three-way solution is potentially even better. Three-way speakers bring new design challenges, of course, in particular the need to achieve another perceptually seamless handover between drivers. But from the Doppler perspective, having a crossover for the bass driver at 400Hz or 500Hz is, unquestionably, better.

https://www.stereophile.com/content/red-shift-doppler-distortion-loudspeakers-page-3)

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[krabapple]

There is no 'myth of flat recordings'. That's nonsense.

And a lot of the rest reads like ancient audiophile nonsense too.