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Talk but not walk?

Hi Guys

This isn't meant to start a fight, but it is important to on lookers. As a qualifier, I have my own audio forum where we report on audio issues as we empirically test them. It helps us short cut on theories and developing methods of listening. We have a wide range of systems and they are all over the world adding their experiences to the mix. Some are engineers, some are artist and others are audiophiles both new and old. One question I am almost always asked while I am visiting other forums, from some of my members and also members of the forum I am visiting is, why do so many HEA hobbyist talk theory without any, or very limited, empirical testing or experience?

I have been around empirical testing labs since I was a kid, and one thing that is certain is, you can always tell if someone is talking without walking. Right now on this forum there are easily 20 threads going on where folks are talking theory and there is absolutely no doubt to any of us who have actually done the testing needed, that the guy talking has never done the actual empirical testing themselves. I've seen this happen with HEA reviewers and designers and a ton of hobbyist. My question is this, why?

You would think that this hobby would be about listening and experience, so why are there so many myths created and why, in this hobby in particular, do people claim they know something without ever experimenting or being part of a team of empirical science folks. It's not that hard to setup a real empirical testing ground, so why don't we see this happen?

I'm not asking for peoples credentials, and I'm not asking to be trolled, I'm simply asking why talk and not walk? In many ways HEA is on pause while the rest of audio innovation is moving forward. I'm also not asking you guys to defend HEA, we've all heard it been there done it. What I'm asking is a very simple question in a hobby that is suppose to be based on "doing", why fake it?

thanks, be polite

Michael Green

www.michaelgreenaudio.net


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uberwaltz's avatar
uberwaltz
13,381 posts
 
I do believe the whole subject of room issues is very real and goes way beyond what  alot of people work at with bass traps and wall diffusers etc.
After all you only need look at some websites to see what some are selling just as off the shelf items,
And I do believe certain people spending years in the research and counterpoint of these effects has been productive.
I wonder though with the wave of the latest electronic correction devices if this has somewhat negated all of this effort?

I wonder just what effect a unit like the Lyngdorf 2170 or Anthem would have on the rooms that already been heavily massaged and tweaked?
Would they be able to improve still further?
Or would they possibly make matters worse?
Be interesting to note the amount of room correction they attempt to make.

Personally I have known my room was acoustically terrible for years but then came along the 2170 and as far as I am concerned it did the "walk" for me and in all honesty I am just about done and really just sit down and enjoy the music for hours on end.
Maybe ignorant bliss and contentment but its my room...lol.
testpilot
930 posts
 
The sound gets refracted ("back" removed) towards the listener due to the change in the transmission medium i.e. hot and cold air


>>>>>I want to get on board your explanation. I really do. Can you be a little more specific and go into detail just a bit? So far I’m thinking hmmmm, maybe partial credit.

 It’s based on the same principle as why can we hear sound for longer distances in winter than in summer. You have already given the theory as to the why and how in the post above.
shadorne's avatar
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shadorne
7,477 posts
 
Since there is no air flow in a listening room you can’t create turbulent flow. You don’t even have laminar flow in a listening room.

Reynolds numbers?

Good grief.

We have such a conflation of different applied sciences here - none of which applies to audio! We are venturing into aerospace engineering and motor vehicle drag perhaps but this is nonsense in audio.

Waves on a beach? Good grief - waves in the sea are NOT elastic acoustic waves at all. Again conflating completely different phenomenon. Surface waves at an interface have orbital progressive properties. The interface is key - just like the major damage from earthquakes comes from “ground roll” at the interface.

The reason acoustic energy varies in a room is due to the reinforcement and interference of a multitude of reflected acoustic waves along with the primary. Since the reflection surfaces are rigid compared to air there is also a build up of pressure very close to the wall. Listeners should keep at least 3 feet from a wall - 6 feet is better.

A little knowledge is a dangerous thing.



theaudiotweak
2,797 posts
 
Fellows you should study up on shear waves and their various velocities and polarities thru and on all solid materials in your listening room including solids in motion. Compressive becomes shear...on impact..or on solids in motion.Tom
geoffkait's avatar
geoffkait
23,365 posts
 
But there is air flow in the listening room, you silly goose. 🦆 For heaven’s sake, don’t have a conniption. 😫 The air molecules are pushed by the high speed acoustic (mechanical) waves, just as waves in the ocean push the water. So, there is laminar flow in the room, and in many directions, obviously. There would not be resonance without mass and there would not be mas without air molecules.

Some examples where baffles are used to organize or maintain laminar flow for audio applications include air baffles for air tubing for my air bearing everything Maplenoll turntable, 500 feet of air tubing, between the air compressor and the air bearing platter and air bearing tonearm AND a small baffle in the air spring connecting air fitting between the auxiliary air canister and the air spring per se, maintaining a smoother flow of air during operation, the air flow velocity in this case must certainly be quite low, no?
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