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Dr. Klaus Heinz of HEDD Audio (ex ADAM Audio) - measuring speakers, in particular speaker dynamics

pozz

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#41
Heinz's point about dynamics seems to involve the question of enclosure volumes.

And my sense is that the big/small comparison was really about mains monitors, like the massive ADAM S6X or Augspurger Quattro, which follow an older design philosophy.
 

DDF

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#42
So despite his 40 years of professional experience of designing loudspeakers, including founding two pro audio loudspeaker companies and running their R&D, you think he doesn't understand speaker design and measurement as well as you do?
Heck no, and I apologize if I gave the impression that I thought that, but I can see it could have been interpreted that way.

I was hoping to be helpful in general by highlighting a few measurements that can be taken (beyond the usual linearity and sine distortion) that could be used to try and get a better handle on the perception of dynamics for a design. By "tripping up", I meant that even after measuring these attributes, it's quite difficult to predict with any high degree of accuracy how they affect the subjective perception of dynamics (which is I think is in line with his statements as well)
 

DDF

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#43
Heinz's point about dynamics seems to involve the question of enclosure volumes.
The thermodynamic equation PV**k = constant shows that the air suspension of the box can create distortion if the air is compressed a high enough % by volume. Distortion resulting is both even and odd order. I think this can have some effect on the perception of dynamics for small boxes with relatively high volume displacement drivers, where the air in the box is asked to work hard. For typical box sizes and woofers, this effect is marginal if at all.

Aside: I think his comments regarding Linkwitz transform reflect that dumping allot of power into a driver for eq can lead to coil and assembly heating that can also affect dynamics.
 

pozz

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#44
I think his comments regarding Linkwitz transform reflect that dumping a lot of power into a driver for eq can lead to coil and assembly heating that can also affect dynamics.
Does this mostly relate to the sub boxes of the HEDD towers, or to the mid/tweeter box as well? And is it only a question of thermal compression of the coil? Are there any volume-dependent effects on the cone's rate of acceleration and settling time in response to a signal?

What do you mean by "typical box sizes"? My impression was that, if anything, the prevailing industry box sizes tend to be too small and that designers tend to focus on designs able to compensate for that. Any differences in sound with large speakers (again, just in terms of perceived dynamics) could be based on that, particularly with large high-excursion drivers.

I'm asking based on intuition by the way. I don't understand speaker construction very well and I would welcome primer materials if you have them.
 

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#45
Listening to a 10 foot tall speaker is not the same as a bookshelf speaker+sub. Just lifting the mid-range and tweeter high will make a big subjective difference. The large image these massive speakers portray is not always to my liking but it is unique.
 

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#46

SIY

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#47
What do you mean by "typical box sizes"?
The only speakers I'm aware of where air volume nonlinearity is significant are things like the Carver and some of the Velodynes, where the woofers are super high excursion and the box sizes are really small. Both of those systems use servo feedback, which greatly reduces that problem. There's a company whose name escapes me at the moment that makes non-servo woofers in very small boxes, but uses a double integrator to equalize them. They get around some of the nonlinearity issues with some clever limiting circuits. That's mostly targeted to pro use rather than consumer.

edit: Just remembered the name: Bag End
 

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#48
Listening to a 10 foot tall speaker is not the same as a bookshelf speaker+sub. Just lifting the mid-range and tweeter high will make a big subjective difference. The large image these massive speakers portray is not always to my liking but it is unique.
“Just lifting the mid-range and tweeter high will make a big subjective difference”. High relative to what? Are you talking pure perception here or real sound? Every speaker has an acoustic axis and if you place the acoustic axis higher (or lower) than your ears, colouration will follow. Right?
 

pozz

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#49

SIY

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#50
Start with Thiele and Small for sure. I don't have the cites handy, but it won't take much looking.
 

amirm

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#51
“Just lifting the mid-range and tweeter high will make a big subjective difference”. High relative to what? Are you talking pure perception here or real sound? Every speaker has an acoustic axis and if you place the acoustic axis higher (or lower) than your ears, colouration will follow. Right?
See: https://www.audiosciencereview.com/forum/index.php?threads/la-audio-show-2017-day-2.1699/page-5



Speakers were pulled way into the room but the room was big enough that the seats were far enough that you didn't get the feeling the speakers were going to fall on you! :)

The sound was relaxed, very dynamic when needed and put a towering image. The images were 2 to 3 times life size though so what you get is not ordinary imaging. Some complained that imaging was diffused. I think this was a factor in addition to the fact that a large room ultimately have has higher reverberation time.

In that regard, these speakers are ideal for orchestral or other large presentation type of music. If I were a fan of classical music or opera, these would be ideal candidates. For close in, jazz and blues music, you would either like them or not depending on whether you want an intimate or bigger than life presentation.

There were no other statement products at the show. Everyone else had brought speakers half the size/height of these. So these speakers stood out in my mind as the best of the show.

I went there twice. The first day I hid in the second row due to worries of getting thrown out of the room because of my Axpona coverage. I went there on the third day and said the heck with it and introduced myself. Got an angry look still but I guess they didn't feel like throwing me out. :)
Integration distance for these tall speakers is longer forcing you to put them in grand rooms and get the above experience. You can't stick two little bookshelf speakers in there and expect the same. Indeed this is one of the issues I have with Kii speakers. For their high price, they don't sound like large speakers that you can buy for the same amount of money.
 

pozz

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#55
Some of you may find this interesting. I can't post a link, but if you search for this, you should find it quickly:

Archives: John Dunlavy (rec.audio.high-end forum posts 1997-2001)
 

DDF

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#56
....thermal compression of the coil?
Howdie,
Klippel's papers contain a wealth of info on driver non linearity:
http://www.klippel.de/know-how/literature/papers.html
Here's an interesting overview by Klippel: https://www.audioxpress.com/article...eption-of-Regular-Loudspeaker-Distortion.html

What do you mean by "typical box sizes"?
Linkwitz created a worksheet to calculate the theoretical % distortion as the air in a closed box is compressed:
http://www.linkwitzlab.com/closed-box1.xls

I don't understand speaker construction very well and I would welcome primer materials if you have them.
Adding to the earlier links:
http://www.musicanddesign.com/tech.html
http://www.linkwitzlab.com/frontiers.htm
https://www.audioholics.com/loudspeaker-design
Harman papers: https://www.audiocircle.com/index.php?topic=58304.0
http://www.silcom.com/~aludwig/
http://www.nutshellhifi.com/library/speaker-design2.html
On Doppler:
http://sound.whsites.net/doppler.htm#s11
John's analysis showing what we call Doppler is overwhelmed by IM distortion due to the same mechanisms:
http://web.archive.org/web/20090809205449/http://www.geocities.com/kreskovs/Doppler1.html
http://web.archive.org/web/20090809205449/http://www.geocities.com/kreskovs/Doppler2.html
http://www.gedlee.com/Papers/papers.aspx
For a rainy day on topic of dynamics: https://www.diyaudio.com/forums/multi-way/108839-dynamics-loudspeakers.html#post1309024
 

pozz

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#57
!
Trust when I say I will actually read all that. Thanks so much DDF, and to everyone else who posted material.
 

FrantzM

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#58
This is a subject that is close to my heart. I tend to favor "big" speakers. It could well be a matter of power compression, of ultimate reach in FR and SPL or of dispersion. I would like dispersion characteristics to be measured at different SPL for example. Are directivity characteristics level invariant? IOW does the directivity remains constant with SPL? I don't know and have not read anything regarding conditions under which directivity is measured... Likely at one level and various angles as it should but at different levels?
In my experience as an audiophile, one I would term "long" at >50 years... I tend to find big speakers more realistic .. "small" speakers even helped with subwoofers to my ears and likely eyes remain "small" sounding. I am not sure a LS50 + Subs (which I had) will match the sheer degree of bigness of a Duntech Sovereign or a Revel Ultima Salon 2 ... It could be a combination of many things and this particular HEDD video however "tainted' it might be, by the need to sell ( Else why even make it?) is revealatory in this regard.
It might be interesting to remark that Rythmik and some other companies now sell, mid-bass "subwoofers" .. small speakers may have issues in this region of special interest
 

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#59
I am not sure a LS50 + Subs (which I had) will match the sheer degree of bigness of a Duntech Sovereign or a Revel Ultima Salon 2 ...
LS-50 with a sub projects the impression of a much larger speaker. But having had them literally next door to a Revel Salon 2 system, it is no match for it.
 
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Music1969

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Thread Starter #60
LS-50 with a sub projects the impression of a much larger speaker. But having had them literally next door to a Revel Salon 2 system, it is no match for it.
Interesting amir. So listening to @mitchco's experiment recordings tells little, compared with the experience of listening in person?
 
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