Quote:They don’t have the tools, nor do they need to have them. Here are the tools that Harman has relative to designing a speaker that performs well in a reflective room.
A speaker is put in anechoic chamber. Inside the chamber there is a microphone array on an arc. The speaker is put on a “spin-o-rama” table that under computer control moves precise number of degrees. At every point, a signal is played by the speaker and data from all the mics captured. At the end of the process, there are 72 measurements of the speaker that shows how the sound radiates from the speaker. Here is what the mic array looks like. Sorry about the crappy quality and poor angle. I was in a hurry when I took it with my point and shoot camera:
Next, computer modeling is applied to the raw data to categorize the signals as direct, early and late reflections in addition to “directivity Index.” Here is the kind of graphs generated from that:
After that, Sean Olive gets involved and his subjective evaluation lab. An automated speaker shuffler is used to evaluate said speaker’s subjective performance. Person sits in front of a curtain and votes on the fidelity of the speaker relative to others without being able to see the speaker itself. All testing is double blind and switch-over time kept short (around 4 to 5 seconds by my timing). Here is what that setup looks like:
The output of that is a report like this:
You then repeat this many times with many testers. One of the largest involved 70 speaker brands/models and some 300 trials. Once there Sean ran an analysis to see if the preference ratings correlates with the spin-o-rama measurements. Wonders of wonders, they did! Turns out you can, based on that data predict how a speaker will perform *in a real room outside of the anechoic chamber!* Let me repeat. The raw data came from anechoic chamber. But the preference tests were done in a real room. Yet a very high correlation of 90% was found between what was measured, and what people preferred. The key measurement that leads to that is the smoothness of directivity index of the speaker which is a measure of how much the direct and indirect sounds of the speaker differ. Get that poppy to be smooth and you too can have a speaker that sounds really good whether the side wall is reflective or not. A good designer armed with this kind of setup can *design* a speaker that sounds good in a room. Indeed, he can predict with high accuracy how it will sound *there* as opposed to the anechoic chamber. I post this graph earlier:
Now you see why it says "speaker" on the right hand side. Because the design of that can very strongly control the sound you hear above the transition frequency. The speaker is in control and the room heavily slaved to it. You know this of course as all you have to do is change the speaker and the tonal quality of the mid to high frequencies radically changes. In low frequencies however, the room takes control and it almost doesn't care what the speaker is going to do. So if you want to "optimize your room," that is what you want to optimize. Don't go optimizing the speaker with the room above the transition frequency. If something is wrong there, get a better speaker. If there is nothing wrong, then leave it alone!
This is the beauty of going to the college of Dr. Toole. He has an integrated story that starts at the beginning (how a speaker is designed and works) and ends in your home (how it behaves once there). It is all stitched together in a logical way with a ton of science, research, psychoacoustics, objective and subjective data. He is not teaching a sub chapter in acoustics relative to absorbers/diffusers whilte leaving the rest of the variables to chance, or untaught. This is why I said earlier that if you bought his book, you will learn a ton about *audio.* Not just what a diffuser or absorber is as most of the books devote themselves into.
Quote:Don’t know about George. I have not seen him in a few years. Next time I see him I will ask him if he has ever been to Harman. Dr. D’Antonio likely knows about all of this research but as I noted, wouldn’t have a need to have any of this. He can rely on the good work of Harman researchers.
And if ONLY Peter D'Antonio (and George Massenburg!) had possessed the right tools and understanding......
Quote:Ah, one of the jewels of the era. May he rest in peace. I think this is a fitting clip:
Cue the theme from the Twilight Zone....On 2nd thought, nevermind...Rod Serling would have rejected this for being far too implausibly absurd - after he was able to stop laughing...