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


128x128michaelgreenaudio

The Tunable Speakers

I’ve been making speakers a long time like many of you. Early on in my adventures I noticed a problem. Everytime I walked into a different recording studio the same speakers sounded different and I ended up spending all kinds of time playing with the EQ to try to find a reference point between the "Live Room" and the "Control Room" and than there was the playback or "Mastering Room". Guys would take the recordings and play them in their cars, and some used headphones and some just decided to suffer through the control room monitors. You’ve all seen pictures of the recording console with several different pairs of speakers. Many times JBL, NS10’s and one or two others on stand by.

In the late 70’s I finally got tired of having to deal with this when I was doing the setups, and I started playing with the idea of making a speaker that I could use with some kind of consistency. For years I would build custom speaker stands and speakers and speaker clamps until I finally landed on something that worked for me. The first tunable speakers were crude torture looking things, but they worked and studios started using them for main mix down monitors the "studio 5". Time went on and I was asked to be the acoustician for UMI (United Musical Instruments). This opened up the door to work more closely with the actual making of horns, wood winds, cellos, guitar, violins, violas and the coolest of cool, building rooms for Steinways.

Around 1989 or so I started to make my speakers out of instrument woods instead of MDF and found tons more tone to play with. This put into action the next 15 plus years in design hunting for the right drivers and parts and pieces so that I could make the most simple to drive speaker that I could (and low mass). For tweeters I used ribbons, silk domes, horns and pretty much the full range of everything I could find. Every time I went more complicated I ended up needing crossover work done and my goal was to go crossoverless. I had found the sound of the cap I wanted to use but drivers were a bugger. Finally I threw out everything and started from scratch. On the cabinet side I was doing pretty well as I got the inside tuning bar down to a science. The Tuning bar works like this. Instead of building heavy cabinets the tuning bar applies the force from the inside and the tuning bolt and washer on the outside supplies the inward force. Because the cabinet has both inside and outside force going on you can adjust the cabinets tone. Where most cabinet designs push outward mine equalize the pressure. The wood of the speaker is low mass compressed board treated with instrument finish. Except for the front baffle board which is a guitar body board. The whole speaker is then veneered in cherry.

The drivers however were a pain. I didn’t like anything I heard. There use to be some nice stamped drivers made in Europe but lately nothing that was what I wanted. I decided on modifying the standard Vifa D27 or ScanSpeak but still I wasn’t happy. Then it dawned on me to make my own baskets. This changed everything. I saw Kosst said I used 3.5" paper tweeters (stamped) as if that was a bad thing lol. Well it would be a bad thing except my baskets are redwood. Again the "walk" Kosst. All my drivers are redwood voiced drivers. The tone is out of this world. Ask the folks who have them. They’re pretty darn snappy pappy:)

The tuning is just as cool as the speaker. Lets say I’m playing cymbals and they are a little loose sounding. Lets say the halos are a tad too wooly. All you do is barely tighten the Tuning Bolt and the cymbal will tighten right up. The new Revs are pretty special. And yes if someone wants the ribbon or silks we do custom sets. We’re doing a set of ribbons right now.

Michael Green

www.michaelgreenaudio.net

I can see some confusion that many people are facing concerning words like laminar flow or pressure zones. Well not to worry even initially I too had a though time trying to wrap my head around it. How would one define the meaning on laminar flow or pressure zones? Where are all these found in a given space or room? What is the first step should I do in order to have an understanding on them? Well these were all the questions that I was asking to myself again and again.

After years of practicing hopefully i could shed some light to those who are still not clear on them. It has got to do with pressure build up by your room itself. For an example if you walk out from a room to an open space your voice will sound open, less focussed and the loudness will be lesser as in comparison when you are in an enclosed space. This is a simple example on what a pressure in a room is causing towords our speakers when they are singing away and activiating or loading a given room. Of course speaker to room size ratio and thier placement is important as that will also determine how much of pressure zones will it activate in a room. Now what we are tuning here are these pressure zones. To give them a much more effective and organized way to work with our speaker and room itself. Pressure zones will be more towards acoustical space within the room itself and laminar flow are the pressure build up around the corners travelling along the walls of the room.

I tune them by using my voice which i hear and feel the resonance within me. Hearing a change of tone and openness in my voice dictates if the flow is moving away or concentrated in that one particular area. Now I'm not here to argue or prove myself at all. Bringing in physics and other methodological manner is not what im interested as what im doing is more than enough for me to understand and make it work for me. But what I would love to hear from others here is to give it a try by voicing yourself in your room and listen for the changes this itself should give you some idea on what is tuning all about. Now from what Michael has mentioned above concerning those simple cardboard excersises was exactly what I did a few years back which brought out a whole different way of thinking and mind set to me in this hobby.

Now onto what Bill has mention concerning on addressing mechanical and eletrical side this is another level of tuning that is equally important. I have removed most of my cable ties in my equipments that I can get my hands on and to be honest I was shocked with the improvments heard and it was a big improvment. As I said I came in with an open mind to what Michael has to offer and was very happy with the results. What got me thinking was how much of improvments I got just from listening to Michaels advise which was tottaly free. Of course knowing that he has such great depth of knowledge eventually gained my trust and of course I looked onto his products to augment my system more.


prof said

"Have you ever considered that this is because tie wraps are irrelevant to the performance of caps?"

prof, why would I use a part without researching it? Prof, it’s my job to not only consider but to test. Also many of the producers of these types of products are happy to exchange info, like folks doing field testing for them.

Can I ask you a simple question so we can see if we can get on the same page somewhat?

How would you describe the difference in sound between the Vishay 1813 (yellow) and the ERO 1822? 3.3 of course.


Awesome, Mike! You built a tweeter that beams like a tactical light at 6KHz! On top of that, it doesn't look like there's anything between the woofer and tweet sections of the cab. Kind of hard to imagine how there would be given the giant hole in the back right between the two sections.  
This whole post is about walking the talk, supposedly, and you claim to have some vast wealth of experience and knowledge, but I'm not seeing it. I'm not seeing any intellectual property here. I'm not seeing measurements. I'm not seeing technical analysis. Did you miss the part where I suggested your power strip is a fire hazard? If that "20G" in the name of the product is meant to suggest that's the gauge of wire used, I hope you go to prison for premeditated murder should one of those cause a fatal fire. At least Geoff is smart enough not to sell things that might kill people. None of your AC power products would pass any kind of certification. Snake oil is one thing. The things I saw on your website illustrate abject ignorance of basic electrical safety. Nothing there suggests an advanced knowledge of engineering or acoustics. 


Someone just mentioned Franck Tchang’s Acoustic Resonators. I mentioned them the other day while discussing mapping the 3D space of the room for sound pressure levels in connection with a number of room acoustics solutions. Since we are discussing pressure zones, sound pressure and air it might be worthwhile to take a gander at what the Stereo Times article says about the Acoustic Resonators. I am posting excerpts from the Stereo Times article below. The entire article can be found at,

http://www.6moons.com/audioreviews/francktchang/resonators.html

Franck Tchang Acoustic Resonators (review at Stereo Times), excerpts

“The resonators also become focal points for intense overtone radiation. That is denser at their points of origin than in the surrounding air. As directional organs, our ears key into these radiation sources and our acoustic perception of the space we’re in is altered. Again, no music needs to be played to sense this spatial overlay. Speech will do, or the sound of our own foot fall. Being completely passive, the resonators can only be activated by received energy. As HF modulators, a full-range input obviously isn’t needed. Franck Tchang has used a spectrum analyzer to corroborate this action up to 3GHz. By affecting the ordinary acoustic damping through adding parallel values from the resonators, original HF content reappears. It becomes audible again and rebalanced against the LF energies. Treble decays improve and the subjective impression of audible space deepens. The resonators equalize air pressure differentials and can be installed in a fridge, mailbox or outside a room. Distance will not affect their efficaciousness. That’s quite a fatal blow to common sense but there it is according to the maestro. Franck has treated recording studios, performance venues, bars, living spaces and entire buildings. His demand as an expert tuning maestro is growing. That brings to mind Combak Corp.’s Kiuchi-San who enjoys a similar reputation in Japan.

The moment you think air exchange where an entire building is submerged in, permeated and surrounded by air (except under the foundation of course), the picture begins to focus. That’s how these resonators defy distance. They’re equalizing the ocean of air that surround us, rechanneling certain turbulences, sync’ing up patterns. If you’ve got a massive geometry-induced pressure zone outside your house for example -- an area where gusty winds get trapped to apply structural pressure -- relieving this pressure must have an audible effect inside. It’s all connected. The mind cracker is simply the clash of scale. Big pressure, tiny devices. LF issues, HF solution. That’s where the mind hangs up. We’ve become conditioned to equate acoustic treatments with <300Hz attacks. That means bass traps. It means huge Helmholz resonators as notch filters. It means giant absorbers and diffusors. Time and again we’ve been told that low frequencies require large devices to counteract. That’s why Rives developed an elaborate in-ceiling address. The ceiling tends to be the biggest blank surface in a room. If high enough, you can hang in a faux ceiling and hide your monster traps in-between.

Think about it. If you sound proof a room by sealing it shut, you increase its internal air pressures the moment music starts. You’re effectively making the room smaller than it was before. That compounds the issue. It’s out of phase with Franck’s views. His isn’t a brute force approach. It isn’t about dominating and straight-jacketing nature. It’s about helping
acoustical energies flow again. It’s about dissipating clusters so that like water which always finds its own level, air pressures level out and equalize. This is a franck response: "I view my room as a bass guitar body, the resonators like strings and the air movement as the player’s hand." According to him and how far I can follow thus far, excess LF energy gets converted to HF radiation by making his resonators work. Work means getting them to oscillate. These devices are passive. They’re not perpetuum mobiles. To keep ringing, the resonators must continue to consume acoustical energy in their environment. However, they’re not drains. Energy isn’t killed by absorption or damping (actually, heat conversion to be technically correct). Acoustic System simply upsamples energy from lower to higher octaves. Bass energy enters the resonators. They oscillate. The resonator in turn puts out harmonics. LF goes in, HF comes out. That seems terribly oversimplified of course. Doubters will point at the fixed resonant frequency of the tiny oscillator and wonder how things add up.“