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High End Munich 2025 - May 15-18

Bjorn said:
He probaly hasn't! I'm not kidding.
Harman's room is not well treated at all. And Toole hasn't done any proper research into quality treatment.
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I don't know how much he had personally done but his book draws on the research done by others as well as himself.

I think he has done consultancy work for recording studios, certainly he has visited studios and there is an anecdote about visiting a newly refurbished studio where they'd gone over the top with diffusion.

Before we all get carried away I don't personally advocate for using no dedicated treatment. It is situation dependant. My room has traditional furnishings so only requires a small amount of dedicated treatment to fix specific problem areas.

For someone with a barren 'Scandi' type room I can see that they would need much more to get a pleasant balance.

The problem arises when the uneducated discover dedicated treatment and immediately assume that if some is good then more is better. And kill the sound a little more with every new bit they add. Since this happens in stages it's like boiling a frog, they don't notice it happening.
 
Paffi said:
I understand what you´re trying. But neither is he god nor is it impossible to make own experiences.
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Agreed. What I was objecting to was the suggestion that disagreement on the subject must be the result of a lack of experience.

In fact, the opposite is the case.
 
Having demoed plenty of speakers in shops, shows or at home, I did realise that the difference in well-measuring speakers is small compared to lack/presence of acoustic treatment in the listening rooms. Reference below to Ethan Winer’s website that has plenty of helpful info on acoustic treatment:

Another reason to avoid early reflections is to increase the apparent width of the music. Many audiophiles believe that reflections in a listening room contribute to spaciousness. On the surface this makes sense, though in truth allowing early reflections makes music sound smaller, not larger. Ambience and reverb already present in many recordings is often of a large space - a concert hall, a movie scoring sound stage, or created with artificial reverb. But when played back in a small untreated room, the strong small-room reflections drown out the larger sounding reverb in the recording. This makes the music sound smaller and narrower, not larger and wider.
 
Bjorn said:
And yet here, among some of the the objective people, acoustic products are considered a scam and something we don't need if speakers have a decent power response....

So much for audio science forum, right?
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Nope. Room treatment is considered a serious matter here.
 
MattHooper said:
And there’s also the possibility of audiophiles seeking different things. You might hear a big horn system and be put off by the coloured frequency response, whereas another audiophile might zero in on what they find to be some exciting or lifelike qualities.

I got to listen a number of times to the Klipsch La scalas at my friends house.
He’s had a ton of high-end speakers in that room, and I could hear some of the frequency response colouration in the Klipsch, but was there ever a sense “life energy” and a dense palpable solidity to the sound that felt more live than the other speakers. Despite their liabilities, I would’ve chosen to listen to those speakers then most of the other ones he had reviewed.

So there can be that element of things to what you are focussed on versus other people.
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I have wondered how much a miniDSP studio could benefit a speaker like the LaScala.
 
For EQ to be effective the speaker’s on has to mirror its off axis
 
Keith_W said:
Can you recommend a good resource for reading about room treatment?
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I first became aware of room treatments as a result of LEDE room theory of Kieth Olsen in the late 70's or 80's, IIRC did a quick Ai query to get links to article about these principles and newer approaches. Hope this is useful:

Keith Olsen's General Philosophy on Room Acoustics:

  • Room Acoustics More Science than Art - Positive Feedback:This article, while not directly by Keith Olsen, reflects a similar scientific and practical approach to room acoustics, emphasizing the importance of understanding sound propagation and treatment. It aligns with the idea of getting the room right to allow the equipment to perform optimally.
Live End Dead End (LEDE) Room Treatment:

Reflection Free Zone (RFZ) Studio Design:

Controlled Image Design (CID) Studio Acoustics:

These resources should give you a solid understanding of these different acoustic design philosophies and how they aim to create optimal listening and recording environments.
 
kevinh said:
I first became aware of room treatments as a result of LEDE room theory of Kieth Olsen in the late 70's or 80's, IIRC did a quick Ai query to get links to article about these principles and newer approaches. Hope this is useful:

Keith Olsen's General Philosophy on Room Acoustics:

  • Room Acoustics More Science than Art - Positive Feedback:This article, while not directly by Keith Olsen, reflects a similar scientific and practical approach to room acoustics, emphasizing the importance of understanding sound propagation and treatment. It aligns with the idea of getting the room right to allow the equipment to perform optimally.
Live End Dead End (LEDE) Room Treatment:

Reflection Free Zone (RFZ) Studio Design:

Controlled Image Design (CID) Studio Acoustics:

These resources should give you a solid understanding of these different acoustic design philosophies and how they aim to create optimal listening and recording environments.
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Excellent, thanks for putting this together.
 
Another aspect of room acoustics for home listening is RT 60 sound decay time. This should be used to determine how much passive treatment to use. Ideally in combination with room eq system like Dirac or Genelec GLM. Usually best to use passive treatments as much as possible to minimize the amount of active RQ needed, also attacking a link to using subs in small rooms to minimize bass problems, getting rid of room modes as opposed to creating more bass:

You're asking about a very important aspect of room acoustics: RT60 reverberation time. It's a key metric for understanding how sound behaves in a space.

Here's a breakdown of ideal RT60 times for home listening and recording studios, along with informative articles:

Understanding RT60

RT60 is the time it takes for a sound to decay by 60 decibels (dB) after the sound source has stopped.




  • Too long RT60:The room sounds "live," "reverberant," or "echoic." Speech can be unintelligible, and music can sound muddy or smeared.

  • Too short RT60:The room sounds "dead," "dry," or "unnatural." It can feel uncomfortable and lacks natural spaciousness.
It's crucial to remember that RT60 is frequency-dependent. You want a relatively even RT60 across the frequency spectrum for optimal sound. Often, low frequencies tend to have longer RT60s, which needs to be addressed with bass trapping.




Ideal RT60 for Home Listening Rooms

For home listening rooms (hi-fi, home theater):

  • General Range: Most sources suggest a range of 0.3 to 0.6 seconds.

  • Smaller rooms (e.g., less than 50 cubic meters/1,800 cubic feet): Aim for closer to 0.3 seconds.
  • Larger rooms (up to 200 cubic meters/7,000 cubic feet): A range of 0.4 to 0.6 secondsis often recommended.

  • Home Theaters: Some recommendations for home theaters lean towards the lower end, around 0.2 to 0.4 seconds, for clear dialogue and precise sound effects.

  • Preference: Ultimately, personal preference plays a role. Some people prefer a slightly "livelier" room, while others prefer a "drier" sound.
Articles for Home Listening Rooms:

Ideal RT60 for Recording Studios (Control Rooms and Live Rooms)

For recording studios, the ideal RT60 varies significantly between the control room (where you mix and monitor) and the live room (where you record instruments/vocals).

Control Rooms:

  • Goal: Control rooms aim for a very precise and neutral sound. This means minimizing early reflections and achieving a relatively short, even RT60 across frequencies.
  • General Range: Typically, 0.2 to 0.5 seconds is recommended.
  • Smaller Control Rooms (e.g., <30 m²): Aim for the lower end, 0.2-0.3 seconds.
  • Larger Project Studios: 0.3-0.5 seconds.
  • Uniformity: It's crucial that the RT60 is as consistent as possible across all frequencies, especially in the midrange and high frequencies, to ensure accurate mixing and mastering decisions. A slight rise in the bass frequencies (e.g., up to 0.4 seconds at low frequencies when mid-range is 0.25 seconds) might be acceptable or even desirable in some cases.
Live Rooms:

  • Goal: Live rooms often aim for a more natural, pleasant acoustic environment suitable for recording various instruments and vocals. The RT60 can be slightly longer than a control room to provide natural ambience.
  • General Range: 0.3 to 0.6 seconds is a common target, depending on the desired sound.
  • Acoustic music/Classical:May benefit from slightly longer RT60s (e.g., 0.6-0.8 seconds) to add "life" and "body" to the sound.

  • Pop/Rock: Often prefer shorter RT60s for a tighter, more controlled sound.
  • Flexibility:Many live rooms are designed with adjustable acoustics (movable panels, curtains, etc.) to allow for varying RT60s depending on the recording needs.
Articles for Recording Studios:

Important Considerations:

  • Small Room Limitations: In very small rooms (typical home studios), the concept of a "diffuse sound field" (which RT60 is based on) doesn't fully apply at low frequencies due to modal resonances. Therefore, other measurements like Early Decay Time (EDT), C50, and C80 (clarity indices) can be more indicative of perceived sound quality in small rooms.
  • Frequency Uniformity: Regardless of the target value, striving for a relatively flat RT60 across the frequency spectrum is crucial for accurate sound reproduction and mixing. Bass frequencies often require the most attention with dedicated bass traps.
  • Measurement:To accurately determine your room's RT60, you'll need acoustic measurement software (like Room EQ Wizard - REW) and a measurement microphone.
By understanding these principles and using these resources, you can make informed decisions about acoustically treating your home listening or recording studio space.


PDF on the use of multiple subs: http://www.gedlee.com/Papers/multiple subs.pdf

More papers from Dr Geddes: http://www.gedlee.com/Papers/papers.aspx


No snake oil from Dr Geddes.
 
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kevinh said:
I first became aware of room treatments as a result of LEDE room theory of Kieth Olsen in the late 70's or 80's, IIRC did a quick Ai query to get links to article about these principles and newer approaches. Hope this is useful:

Keith Olsen's General Philosophy on Room Acoustics:

  • Room Acoustics More Science than Art - Positive Feedback:This article, while not directly by Keith Olsen, reflects a similar scientific and practical approach to room acoustics, emphasizing the importance of understanding sound propagation and treatment. It aligns with the idea of getting the room right to allow the equipment to perform optimally.
Live End Dead End (LEDE) Room Treatment:

Reflection Free Zone (RFZ) Studio Design:

Controlled Image Design (CID) Studio Acoustics:

These resources should give you a solid understanding of these different acoustic design philosophies and how they aim to create optimal listening and recording environments.
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What's written here about LEDE is incorrect.

They are describing how LEDE started out, but LEDE developed into something very different over the years. It was for many years in development because of breaktroughs in measurements and new products.

RT60 can't be used for small room acoustics. Reverberation time requires a diffuse field.
 
That is one reason to use diffusion in a room to control the RT 60. I have heard 'dead' rooms and 'live ' rooms, YMMV. If you read what the AI generated, you will not that the ideas behind LEDE rooms and what is 'best' have indeed changed. When this information was first published, it was quite a change from an area most weren't aware of to one that many of us found to be helpful.
 
In my 48m3 room the RT60 is 0.29 to 0.32 seconds from 400Hz (ish) to 3600Hz (ish) which is perfect for my Detroit techno and the 90% electronic music listening habits that I have.

I got my chimney cleaned a few weeks ago along with two wall vents being fitted (dust/mess/soot) and had all my 19 panels removed from their hooks and hid in the bedroom for the day, when it came to refitting them my mum and brother brought them through one by one and hung them, I was naturally sat on my arse on the chair listening to my music and the difference each few panels made was really dramatic (I was playing Plastikman : Musik) and by the time the final two 1200mm x 600mm 8” bass panels were hung on the rear wall along with the 1200mm x 600mm 6” diffuser/absorption panel I knew I had definitely made the right choice 5 years ago to do room treatment before I considered my current system.
 
Somafunk said:
... when it came to refitting them my mum and brother brought them through one by one and hung them, I was naturally sat on my arse on the chair listening to my music and the difference each few panels made was really dramatic
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Your dedication to acoustic treatment research is appreciated!
 
Audio Science Pal said:
Your dedication to acoustic treatment research is appreciated!
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There’s a reason I sat on my arse :D

I managed to help my mate do room sweeps and position them/drill holes for final mounting 5 odd years ago but my SPMS has progressed to the point that I’m totally fu***ng useless for anything these days, unless you count pontificating about shit online counts for much ;)
 
Somafunk said:
There’s a reason I sat on my arse :D

I managed to help my mate do room sweeps and position them/drill holes for final mounting 5 odd years ago but my SPMS has progressed to the point that I’m totally fu***ng useless for anything these days, unless you count pontificating about shit online counts for much ;)
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Sad to hear this.
 
Pearljam5000 said:
Unfortunately no
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I hope you're not disappointed like I was with the Generec. I had high expectations since I'm very familiar with active systems, and although the Generec doesn't sound bad—in fact, better than many at the show—it was still clear to me that simply forcing the EQ with a DSP isn't enough to achieve the flat response that those who only measure data like.
For me, with zero dynamics, everything sounded lifeless, although everything was very correct.
My wife and daughter, with no brand bias, unanimously agreed.
My question is, do they really measure well, and should we therefore convince ourselves that this is the sound we like?
Before buying an 8381a, I would buy a Kroma a thousand times over, and I'd have some money left over. Sure, the Kroma doesn't measure as well as any Generec, but we don't hear it as if we were a measuring instrument.
 
Can’t find any measurements for Kroma?
Keith
 
Purité Audio said:
Can’t find any measurements for Kroma?
Keith
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No, I haven't looked up Kroma's measurements... and honestly, I don't need to, although I presume they'll be fine. They won't be nearly perfect like Generec. They've already analyzed some of their models here, and they measure extraordinarily well. But this is precisely what I'm trying to say:

Many of the speakers that "measure perfectly" in an anechoic chamber or in tests end up sounding sterile and lifeless in reality, or at least for me. Perhaps I have defective hearing, along with my family's. That's where the difference between designing for the human ear or for a microphone comes in.
 
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