What role should listening play in speaker design

[Audionaut]

To be clear, the topic is about how professional speaker designers apply listening to their design process (to build objectively accurate speakers).

I don’t think all professional speaker designers aim to build objectively accurate speakers.
For many speaker designers, the goal is likely still to achieve a sound that is as pleasing and impressive as possible—the typical “loudness war” Spotify-style audio found in the subpar listening rooms of major electronics chains.
I also believe that some speaker manufacturers cultivate a specific sound signature that can be discerned, for example, through dispersion characteristics, a boost in the midrange, or a slight “bathtub” tuning.

 

[RickS]

I don’t think all professional speaker designers aim to build objectively accurate speakers.
For many speaker designers, the goal is likely still to achieve a sound that is as pleasing and impressive as possible—one that quickly stands out from the typical “loudness war” Spotify-style audio found in the subpar listening rooms of major electronics chains.
I also believe that some speaker manufacturers cultivate a specific sound signature that can be discerned, for example, through dispersion characteristics, a boost in the midrange, or a slight “bathtub” tuning.

Agree, but not the designers you usually find on ASR (as members or subjects) but let’s stick to those that do.

 

[sigbergaudio]

I guess the temporary thread locks help cool down the temper of people, but it also slows down the discussion.

With limited moderation capacity, I understand that it may be the only viable option.

 

[MattHooper]

Agree, but not the designers you usually find on ASR (as members or subjects) but let’s stick to those that do.

Would Andrew Jones be in that category?

 

[RickS]

Would Andrew Jones be in that category?

He is in the OP and he has demonstrated a propensity towards accuracy in many of his recent designs. As I mentioned, speaker design is not perfect science. Maybe a better way better statement would be designers that demonstrate a propensity for applying objective measurements. There is wiggle room but if they are not members, may need to show that they have some objective credibility.

 

[Lars Risbo]

just took the time to hear the AJ clip. I tend to agree with most of what he said. Measuring a loudspeaker correctly is extraordinarily difficult. Even large anechoic rooms and NFS are imperfect and we do not have a reference to compare with. Secondly, we can’t do a perfect speaker and the character is in the imperfections. The designer picks the best compromise within a budget. This compromise may be subjective based on personal preference. Last point is that the absolute truth of reproducing the artist sound does not exist. The recording process makes artistic choices.

I read multiple comments about we audio designers tell stories just to please the crowd or simply for commercial gains. I find this depressing. If I wanted to make money then I would not be designing audio gear. My motivation is to create stuff that I would love to have myself but does not yet exist. I can then only hope that others may like it too.

 

[sigbergaudio]

just took the time to hear the AJ clip. I tend to agree with most of what he said. Measuring a loudspeaker correctly is extraordinarily difficult. Even large anechoic rooms and NFS are imperfect and we do not have a reference to compare with. Secondly, we can’t do a perfect speaker and the character is in the imperfections. The designer picks the best compromise within a budget. This compromise may be subjective based on personal preference. Last point is that the absolute truth of reproducing the artist sound does not exist. The recording process makes artistic choices.

I read multiple comments about we audio designers tell stories just to please the crowd or simply for commercial gains. I find this depressing. If I wanted to make money then Inwould not be designing audio gear. My motivation is to create stuff that I would love to have myself but does not yet exist. I can the. only hope that others may like it too.

I second all of this, wholeheartedly agree.

 

[RickS]

just took the time to hear the AJ clip. I tend to agree with most of what he said. Measuring a loudspeaker correctly is extraordinarily difficult. Even large anechoic rooms and NFS are imperfect and we do not have a reference to compare with. Secondly, we can’t do a perfect speaker and the character is in the imperfections. The designer picks the best compromise without a budget. This compromise may be subjective based on personal preference. Last point is that the absolute truth of reproducing the artist sound does not exist. The recording process makes artistic choices.

I read multiple comments about we audio designers tell stories just to please the crowd or simply for commercial gains. I find this depressing. If I wanted to make money then Inwould not be designing audio gear. My motivation is to create stuff that I would love to have myself but does not yet exist. I can the. only hope that others may like it too.

Would just like to add or clarify regarding sequencing. My professional experience with product development is that we would have target requirements. I expect that anyone hoping to sell a product targets a certain market. For a speaker, the target may have more or less tendency to be accurate. In some cases, the product may have some intentional tonal profile. A good speaker engineer would be able to achieve that tonal profile. In a smaller company, I understand a designer may wear many hats though…

I’d expect the subjective compromises for speaker that targets accurate sound will be much less. I think that is what you meant as I would struggle if the target speaker requirements changed while designing. Do you concur or is your process different?

 

[RickS]

Some further thread guidance to add. As part of curation and encouraging designer participation in this thread, posts should be respectful and focused on design topics. Negative personal commentary will be deleted.

Have not stated in this thread, but there often can be many ways to make a good product. There is rarely one right way. Unless we allow designers to be candid and not heckled over their posts, cannot expect them to want to contribute.

 

[Sokel]

just took the time to hear the AJ clip. I tend to agree with most of what he said. Measuring a loudspeaker correctly is extraordinarily difficult. Even large anechoic rooms and NFS are imperfect and we do not have a reference to compare with. Secondly, we can’t do a perfect speaker and the character is in the imperfections. The designer picks the best compromise within a budget. This compromise may be subjective based on personal preference. Last point is that the absolute truth of reproducing the artist sound does not exist. The recording process makes artistic choices.

I read multiple comments about we audio designers tell stories just to please the crowd or simply for commercial gains. I find this depressing. If I wanted to make money then I would not be designing audio gear. My motivation is to create stuff that I would love to have myself but does not yet exist. I can then only hope that others may like it too.

Selling a story instead of a naked product is neither positive nor negative, is just an easier way to get to most people.

Stories can differ though, one of them for example can be story behind developing a speaker, the target, etc.
As a consumer, I would like to know the practical side also, like, its intended use some guidance regarding set-up, etc.

And then there's the compromises. which at these days and age where the goal for accurate sound may be easy for smaller gear, higher SPL seems to be sacrificed as bigger stuff are more expensive, harder to test, and with the later ethics (which I hate) of buying-listening-returning can be a nightmare.

From a company's side, measuring and listening covers all bases.
And as a curious person, I wouldn't even imagine a designer not rushing to listen the fruits of it work.

How useful is this, its up to the trade I guess and I really appreciate your insights to it.

 

[witwald]

In some cases, the product may have some intentional tonal profile.

I think that may be vying for the Understatement Of The Year Award.

 

[RickS]

I think that may be vying for the Understatement Of The Year Award.

Lol, maybe needed a better compare and contrast, but meant a speaker that was not targeted to have flat on-axis response. Once again, the thread focus is about how listening plays a role in design. There are a lot of variables in speaker design, keeping to flat response is just an attempt to simplify this topic.

 

[Pearljam5000]

So which audio brands have speaker designers with the best hearing, judging by their designs and products ?

 

[RickS]

So which audio brands have speaker designers with the best hearing, judging by their designs and products ?

Definitely a topic for another thread!

 

[witwald]

"Initial comparative listening tests, using varied programme material*, suggested that the reproduced sound was less coloured by the LS 5/8 than by any other loudspeaker so far tested at Research Department. Nevertheless, audible colorations are present, and the most noticeable of these is at about 600 Hz. A low-Q notch filter at this frequency was therefore inserted and it was found that a 2 dB dip produced a marked subjective improvement without noticeably affecting the tonal balance. *This included serious music (solo instrumental, orchestral and choral) as well as light music and speech."

The above quote was taken from "Design of the high-level studio monitoring loudspeaker type LS 5/8", C.D.Mathers, M.Sc., M.I.E.E., BBC Research Department Report 1979/22 (November 1979). Hence, it seems that listening does/should play a role in the design of loudspeakers. It 'twas thus in the 1970s, and not much has changed since that time. The need for that 2 dB dip mentioned above seems to be a self-evident adjustment based on the simple measured on-axis frequency response curve, shown below. This still shows a bit of relative boost in the 500 Hz to 1000 Hz frequency region, which almost seems to be compensating for the broad dip in the 200 Hz to 500 Hz region. Note the mislabelled 500 Hz frequency in this graph.

 

[DavidR]

speaking of distortion: the desire to voice away from flat on axis can be due to distortion. eg making voices harsh and then a BBC like dip may soften it. With low distortion, i think that ruler flat on axis works best.

I haven't read through this entire thread yet, but searched to see if anyone made reference to the "BBC dip". While putting together a distortion testing rig and learning REW I have been doing online research and happened upon a short section at Siegfried Linkwitz's site that I think has some relevance. He makes a point about recordings with regard to how he modifies his designs. This is from his web page here (emphasis mine).

H - Psycho-acoustic 3 kHz dip
Our perception of loudness is slightly different for sounds arriving frontally versus sounds arriving from random directions at our ears. The difference between equal-loudness-level contours in frontal free-fields and diffuse sound fields is documented, for example, in ISO Recommendation 454 and in E. Zwicker, H. Fastl, Psycho-acoustics, p. 205.
Diffuse field equalization of dummy-head recordings is discussed in J. Blauert, Spatial Hearing, pp. 363, and headphone diffuse field equalization by G. Theile in JAES, Vol. 34, No. 12.
Reference to a slight dip in the 1 to 3 kHz region for loudspeaker equalization is made in H. D. Harwood (BBC Research Department), Some factors in loudspeaker quality, Wireless World, May 1976, p.48.

Around 3 kHz our hearing is less sensitive to diffuse fields. Recording microphones, though, are usually flat in frequency response even under diffuse field conditions. When such recordings are played back over loudspeakers, there is more energy in the 3 kHz region than we would have perceived if present at the recording venue and a degree of unnaturalness is introduced.
This applies primarily to recordings of large orchestral pieces in concert halls where the microphones are much closer to the instruments than any listener. At most listening positions in the hall the sound field has strong diffuse components.
I use a dip of 4 dB (x1.gif, 2760NF) to equalize for this. The circuit consists of R, C and L in series, forming a frequency dependent ladder attenuator in conjunction with the 5.11k ohm source resistor. You may choose to make the notch filter selectable with a switch for different types of recordings.

I have found through my own head-related recordings of symphonic music that the dip adds greater realism, especially to large chorus and to soprano voice and allows for higher playback levels.

In my own 3-way I used for years I, too, found that a slight "BBC dip" from 1-3kHz made for a very slight recess in good recordings, especially female vocalists, most often in well recorded acoustic spaces. The tonal character didn't change, but well recorded and engineered recordings...just sounded better. Whether or not that was due to something inherent in my system or in the recordings I can't say. Maybe it's artificial. I only know that I "preferred" that. I doubt my wife would even have detected that even if she had had the patience to try.

 

[witwald]

In my own 3-way I used for years I, too, found that a slight "BBC dip" from 1-3kHz made for a very slight recess in good recordings, especially female vocalists, most often in well recorded acoustic spaces. The tonal character didn't change, but well recorded and engineered recordings...just sounded better. Whether or not that was due to something inherent in my system or in the recordings I can't say. Maybe it's artificial. I only know that I "preferred" that.

How deep was the frequency response dip that was typically used in this instance?

Harwood suggested using only 2 dB. In comparison, Linkwitz's approach of dipping by 4 dB seems a lot more heavy handed. Was this done to make the effect much more audible?

A more complete sense of Harwood's thinking on the subject may be gleaned from the following longer excerpt from his article. Note his concern about "destroying the sound quality".

"The usual conclusion is that the loudspeaker should also have a uniform axial frequency response but this is precisely what is being challenged. Not even in stereo reproduction are the sound wave-fronts produced in a listening room similar to those heard in the studio or concert hall and it therefore seems clear that if by "bending" the axial response curve of the loudspeaker a more realistic psychological impression is obtained, then this is entirely justified. Thus, for example, if a uniform output is maintained at all frequencies an orchestra sounds extremely close.

This condition is quite unnatural and a much better sense of perspective is obtained if a slight dip in the 1 to 3kHz region is applied. About 2dB is sufficient to provide the more distant perspective without destroying the sound quality. It may well be that as techniques progress other such tricks will follow. All that is intended at this stage is to get away from the rigid idea that a uniform axial response is necessarily the best."

"Some factors in loudspeaker quality", H. D. Harwood, Wireless World, May 1976, pages 45–48, 51–54.

 

[DavidR]

How deep was the frequency response dip that was typically used in this instance?

Harwood suggested using only 2 dB. In comparison, Linkwitz's approach of dipping by 4 dB seems a lot more heavy handed. Was this done to make the effect much more audible?

I used 1dB, shallow Q such that it was almost entirely within 1-3dB. 4dB does seem a bit extreme to me as well. He explained his reasoning.

I have found through my own head-related recordings of symphonic music that the dip adds greater realism, especially to large chorus and to soprano voice and allows for higher playback levels.

Certainly a lot has changed in both recording and playback technology (headphones, speakers) since the time of Harwood, so that may help to explain the 4dB dip that Linkwitz found to work for him. Of course that also appears to have been from his own recordings. How that would impact other recordings remains a question.

 

[DavidR]

This line from that excerpt is, I think, appropriate to emphasize given the topic of the thread.

All that is intended at this stage is to get away from the rigid idea that a uniform axial response is necessarily the best.

It would seem that Linkwitz agreed with with this. If I recall correctly his priorities were 1) direct first arrival and 2) power response. Neither of which are the same as the axial response (as measured at the typical 1m that is).

 

[NTK]

This line from that excerpt is, I think, appropriate to emphasize given the topic of the thread.

It would seem that Linkwitz agreed with with this. If I recall correctly his priorities were 1) direct first arrival and 2) power response. Neither of which are the same as the axial response (as measured at the typical 1m that is).

What is the difference between direct first arrival and axial response?