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An Enticing Marketing Story, Theory Without Measurement?

Thomas_A

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Interestingly Genelec, up until recently at least - I have not checked lately - followed the guidance of the ISO and EBU standards (they are the same) because of their business with the broadcast industry. In brief, these standards require loudspeakers with anechoic (1/3 octave smoothed) on axis responses that are flat within +/- 2dB. OK. But then they tell users to measure steady-state in-room curves and adjust as necessary to make them flat (with a large tolerance). Unless one is listening in a non-reflective environment, or extremely close to the speaker, one cannot have both. There are more shortcomings of the standards, but this is a very bad start. In normally reflective rooms the steady-state room curve from well designed, neutral, loudspeakers will tilt downwards - they are flat and smooth on axis as measured in an anechoic space.

This emphasis on steady-state room curves above the transition frequency is wrong - it is a poor correlate of sound quality. My JAES paper cited in the first post in this thread explains, as does my book. It is embarrassing to look at the performances of some "reference" pro monitor loudspeakers over the years. Several spinoramas are shown in my book, especially Chapter 18.
Thats bad, but I hope it will change if it has not done so already. Proper education of technicians in the studio is needed, now when you more freedom to adjust those active speakers.
 

TimVG

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Interestingly Genelec, up until recently at least - I have not checked lately - followed the guidance of the ISO and EBU standards (they are the same) because of their business with the broadcast industry. In brief, these standards require loudspeakers with anechoic (1/3 octave smoothed) on axis responses that are flat within +/- 2dB. OK. But then they tell users to measure steady-state in-room curves and adjust as necessary to make them flat (with a large tolerance). Unless one is listening in a non-reflective environment, or extremely close to the speaker, one cannot have both. There are more shortcomings of the standards, but this is a very bad start. In normally reflective rooms the steady-state room curve from well designed, neutral, loudspeakers will tilt downwards - they are flat and smooth on axis as measured in an anechoic space.

This emphasis on steady-state room curves above the transition frequency is wrong - it is a poor correlate of sound quality. My JAES paper cited in the first post in this thread explains, as does my book. It is embarrassing to look at the performances of some "reference" pro monitor loudspeakers over the years. Several spinoramas are shown in my book, especially Chapter 18.

Dr. Toole, I've just read the EBU document (https://tech.ebu.ch/docs/tech/tech3276.pdf) and I see indeed guidelines for monitor (anechoic) frequency response tolerances, directivity guidelines, loudspeaker positioning, room treatment etc. They give an 'operational room curve example' and guidelines but there appears to be quite some tolerance to this, which would still allow, if I interpret the document correctly, the natural response of whatever a "good" loudspeaker does naturally in a treated room above the transition frequency. In fact in the notes of the operational room curve it states:

To avoid degrading the quality of reproduction, electrical equalization should be used carefully. It is advisable to make the corrections in the low–frequency range (f < 300 Hz) only.

Follow by a "All channels should be adjusted in the same way." .. I hope they mean adjusted to the same target ,below 300Hz.
 

JoachimStrobel

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It seems to me, that the underlying problem is not having the original sound source available for comparison. If I had Norah Jones playing in my living room, I could hear how close I am. And for sure my ear and my brain will factor the room into the equation, knowing that she sounds differently in the jazz club than in my home.
I have a grand piano that I moved around in my house for various reason, I had it in 4 rooms by now. Each one sounded different. It is surely too bright in a small room, so I keep the lid closed then. I will improvise differently having the piano open or closed as the feedback stimulate is different.

This is hardly a circle of confusion but more a fact of live.

The situation is almost identical to the color temperature with photos. We can “see” the color of a skin, the nuances, looking at that person under an overcast sky with a color temperature of 7000 kelvin in the same way as looking at that person in a dim home with 2000K. Photos taken in both situations will show a dramatically different skin tone and trying to correct it can be a nightmare. That is similar to microphones and room curve assessment.

The photo industry has standardized to reproduce colors for D65= 6500 k. Many TV run at 10000 k as it looks brighter, indoor wall photos have to live with 2500K. Some people have calibrated screens - same thing as Equing a room. People mostly do that to produce consistent prints, but hardly to create color fidelity for people’s screens as they are so different. Apple may change that workflow in future with their auto-calibrating Ipad screens.

The music industry could standardize in a similar way. Like mix all music for a 30m2 living room with a typical set of furnitures. And Amazon could change that workflow too, with their auto-calibrating Studio Alexa...

And Audiophile should buy an instrument, may be a flute or learn to sing, and a recording device to check that sound reproduction with their system and their room fits their needs.
 

digicidal

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And Audiophile should buy an instrument, may be a flute or learn to sing, and a recording device to check that sound reproduction with their system and their room fits their needs.
That's a great idea! It will be a long time down the road and will require more gear than I currently have, but I'll record my mother-in-law singing and playing guitar in my media room and then play that recording through my gear and record that and then do some comparitive analysis on both files.
To be honest I don't expect any revelations from that per se - but it does seem like a fun way to spend a weekend from a hobbyist perspective.
 

Blumlein 88

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It seems to me, that the underlying problem is not having the original sound source available for comparison. If I had Norah Jones playing in my living room, I could hear how close I am. And for sure my ear and my brain will factor the room into the equation, knowing that she sounds differently in the jazz club than in my home.
I have a grand piano that I moved around in my house for various reason, I had it in 4 rooms by now. Each one sounded different. It is surely too bright in a small room, so I keep the lid closed then. I will improvise differently having the piano open or closed as the feedback stimulate is different.

This is hardly a circle of confusion but more a fact of live.

The situation is almost identical to the color temperature with photos. We can “see” the color of a skin, the nuances, looking at that person under an overcast sky with a color temperature of 7000 kelvin in the same way as looking at that person in a dim home with 2000K. Photos taken in both situations will show a dramatically different skin tone and trying to correct it can be a nightmare. That is similar to microphones and room curve assessment.

The photo industry has standardized to reproduce colors for D65= 6500 k. Many TV run at 10000 k as it looks brighter, indoor wall photos have to live with 2500K. Some people have calibrated screens - same thing as Equing a room. People mostly do that to produce consistent prints, but hardly to create color fidelity for people’s screens as they are so different. Apple may change that workflow in future with their auto-calibrating Ipad screens.

The music industry could standardize in a similar way. Like mix all music for a 30m2 living room with a typical set of furnitures. And Amazon could change that workflow too, with their auto-calibrating Studio Alexa...

And Audiophile should buy an instrument, may be a flute or learn to sing, and a recording device to check that sound reproduction with their system and their room fits their needs.

Pretty good post. I would take issue with your last sentence. If you sing, and/or play an instrument, you'll never be in a position to judge the recording and the reference. The performer has no idea how they sound to someone a few feet away. You need a singer or player you can listen to and record. Then you can compare what you heard a few feet away vs what the recording sounds like. With the right considerations you can do pretty good with this. I'll let others have the fun of discovering it for themselves. It is an educational thing to do.
 

TimVG

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The original sound source is the recording. Every form of source material is an artificial creation using a vast chain of equipment. All judged by playing back through monitors. If the playback is not true to the source, it becomes a guessing game.
 

TimVG

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Is anyone really naive enough to think that simply using a zoom pocket recorder and have someone sing or play while you record will give you an accurate assessment of your hifi system?
 
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JoachimStrobel

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Pretty good post. I would take issue with your last sentence. If you sing, and/or play an instrument, you'll never be in a position to judge the recording and the reference. The performer has no idea how they sound to someone a few feet away. You need a singer or player you can listen to and record. Then you can compare what you heard a few feet away vs what the recording sounds like. With the right considerations you can do pretty good with this. I'll let others have the fun of discovering it for themselves. It is an educational thing to do.
... you are right. I did not think this thru enough, needs two hobbyist or rather amateurs ( as in “doing it for the love of it”), one for listening and one for playback.
 
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Hipper

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The original sound source is the recording. Every form of source material is an artificial creation using a vast chain of equipment. All judged by playing back through monitors. If the playback is not true to the source, it becomes a guessing game.
As Floyd Toole said, a Circle of Confusion.
 

digicidal

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Is anyone really naive enough to think that simply using a zoom pocket recorder and have someone sing or play while you record will give you an accurate assessment of your hifi system?
A few perhaps... however some, myself included, might think it will rather make for an enjoyable casual experiment and expose the significant differences between the two. However, if you mean subjectively then no, not at all. I really just want to compare the two files to quantify exactly how much is being lost in the process (more accurately than "a crap-load"). ;)

Many experiments IME don't actually accomplish much at all - but if I learn even a tiny bit I didn't know before... then time well spent!
 

oivavoi

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I have a grand piano that I moved around in my house for various reason, I had it in 4 rooms by now. Each one sounded different. It is surely too bright in a small room, so I keep the lid closed then. I will improvise differently having the piano open or closed as the feedback stimulate is different.
Excellent post. I also play the piano, and have tried the piano in different rooms, and in different positions in the living room. Same experience here: It sounds really different! I actually try to do some "room correction" with the piano though. At the current position, it was somewhat too bright, because it is standing in a corner with reflective walls which probably reflect more of the higher than the lower frequencies. So the first thing I did was to experiment with adding more carpeting etc around it. That helped quite a lot. But I also asked my piano tech to voice it down - to make it sound a bit darker. That also helped.

When it comes to hifi and speakers, the same thing applies, I think. Light broadband eq, based on the response in the room, is never a bad thing. As is taking down excessive energy in the bass. Beyond that... hm, I'm somewhat skeptical.
 

TimVG

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People - as a concert musician, amateur loudspeaker builder, and all around 'gear nut' - there is a large difference between acoustic spaces intended for performance and for playback purposes.

Whatever your desire in terms of listening space, be it quite dead, quite lively or something in between: start by knowing your loudspeakers. Anehoic data is absolutely needed to make any assessment whatsoever. Once you have loudspeaker with a neutral direct sound, and well behaved off-axis .. Then there's really not much more to be done in that department, above a couple of hundred Hz. Then you should start by looking at treating your room.
 

oivavoi

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People - as a concert musician, amateur loudspeaker builder, and all around 'gear nut' - there is a large difference between acoustic spaces intended for performance and for playback purposes.

Whatever your desire in terms of listening space, be it quite dead, quite lively or something in between: start by knowing your loudspeakers. Anehoic data is absolutely needed to make any assessment whatsoever. Once you have loudspeaker with a neutral direct sound, and well behaved off-axis .. Then there's really not much more to be done in that department, above a couple of hundred Hz. Then you should start by looking at treating your room.
I think this is good advice in general. But wouldn't you say that it makes sense to adjust the broadband tonal balance of the loudspeakers based on the response in the room? In a room where all the walls were made of glass, I'm pretty sure I would have liked to turn down the treble a bit. But in a room where all the walls were covered with heavy curtains or carpets, I would probably have wanted to turn the treble up a bit. This seems quite intuitive to me, at least?
 

TimVG

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I've never found that helpful, personally. You cannot EQ a loudspeaker to fix problems that are not created by it, in this case, overly lively or dead rooms. A good loudspeaker, in a good room.. We listen 'through' rooms, but we can't ignore it either.
 

TimVG

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The noteworthy studies that have been performed have concluded that independent of the room, loudspeakers with a neutral direct and indirect sound, are rated higher compared to non-neutral speakers. This doesn't mean that the room can't affect the score, but it won't affect the preference order.
 

oivavoi

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The noteworthy studies that have been performed have concluded that independent of the room, loudspeakers with a neutral direct and indirect sound, are rated higher compared to non-neutral speakers. This doesn't mean that the room can't affect the score, but it won't affect the preference order.
Fully agree. I believe there have been done two studies which looked at the effect of the room on impressions of loudspeaker quality, and if I remember correctly they did show that the brain usually adapts tonally to the room, and compensates somewhat for what the room does.

But I don't think there have been done any studies which investigate whether people who listen in a room made of glass will prefer to dial down the treble or not. If such a study gets done, and it shows that people don't want the treble to be tone down in such a room, I would be fairly surprised.
 

TimVG

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If anything I'd put in a bit more treble since speakers generally disperse higher frequencies in a narrower pattern, causing them to be underrepresented in a very reverberant environment, this speaking from an intelligability pov
 

Absolute

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Tonal perception isn't just about sound power, it's also about time. I don't get why it can't be beneficial to adjust power to compensate for differences in decay across the frequencies, even though you're changing the direct sound.
@Floyd Toole ?
 

TimVG

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Because as you say, it's also about time. The first sound to arrive at our ears is what defines the timbre. The room and the speaker are two different things, that work together. You cannot change a flaw in the room by changing aspects of the loudspeaker.
 
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