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Re: Some popular misconceptions


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6/29/2000 12:39 PM
Steve Slick
Re: Some popular misconceptions
Mikie,  
 
Hahahahahahahahah! That line about Nigel's amp going up to 11 is one of my favorites of all time. I can't decide if I want that on my tombstone, or "…and as he got older, he got worse."  
 
I couldn't tell you how many times I've mentioned that. For example, recently, my company terminated a couple of really good contractors who had been here 6 months to save money.  
 
I got slightly furious. I said, but we'll need them again in the future and they won't be here. Then, we'll have to go find and interview more candidates while people sit around waiting for them and hope we can get other ones as good (probably not, though). Then they'll take a few weeks (actually months) getting up to speed with what we do, our business environment, etc. In other words, we'll spend a lot more money to make up for the money we saved!  
 
But when I made this pitch some of the other managers gave me that glassy-eyed stair, and after a while they said, "Yeah, but we're saving money."  
 
I jumped up and said, "What is this? The set for Spinal Tap? Yeah, but mine goes up to 11." Nobody understood what I meant. But it didn't matter. When I explained it from the movie, an engineer actually said, "So what's the big deal. His did go up to 11!"  
 
I finally said, "You know, you're right. It sure did!"  
 
Hahahahahahahahah!  
 
Cheers,  
 
Steve Slick
 
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6/28/2000 7:35 PM
J Epstein
Would you add Blumlein to that list?
The recent bio (I have read only reviews) seems to set him up as a standard-bearer of the first rank too.  
 
-j
 
6/28/2000 9:54 PM
Stephen Conner

Of course! This is the guy who invented and patented stereo sound. He actually set the principles of stereo down mathematically so that if you followed his technique from mic to loudspeaker, you were guaranteed the best possible soundstage. Some audiophile recordings are still 'Blumlein miked' to this day.  
 
P.S. Respect to Mark for that great post on psychoacoustics.  
 
Steve C.
 
7/1/2000 4:54 AM
Mark Hammer
Didn't know Blumlein before now (shame on me). Thanks for the tip (and the flattery).  
 
The best money I ever spent on my stereo was the $75 I spent on an Omnisonic Imager. This is one of those gadgets that came out in the early 80's that essentially launched the "second wave" of psychoacoustics-driven audio engineering (#1 being the invention of stereo, #3 being digital signal processing). A bunch of people made them: Carver, Radio Shack. I even made one from a Radio-Electronics project.  
 
Up until that time, stereo had essentially been a matter of keeping the left vs right levels of different signals separate. Somewhere in the 60's or 70's (wish I knew exactly when) it dawned on folks that in the real world, sounds that were off-axis (i.e., not straight in front of you, equidistant between your ears) not only had a difference in amplitude between what each ear heard, but had differences in timbre, differences in initial arrival time, and differences in the reflected sound they got. Clearly, unless this stuff was addressed, closing your eyes while listening to "stereo" was not going to equal the experience of being there.  
 
Enter BBD chips. These little suckers made it feasible to introduce broad-band time-delay inexpensively with decent fidelity.  
 
What these imaging devices did was to produce two difference signals (L-R, R-L), extracting everything that was exclusive to each channel and eliminating anything that was shared between channels. These difference signals were then crossfed to the *opposite* channel (i.e. uniquely left stuff mixed in with original Right channel) at a lower volume, AFTER being delayed a couple of milliseconds, and lowpass filtered. The delay does not produce any audible echo or reverb. It simply creates a time difference in arrival at each ear for the same program material. So, if a maraca is panned hard left, you will hear it slightly quieter, with a bit less high end in the right ear, just a few milliseconds later.  
 
The result? Outstanding stereo! You don't really notice it that much when you turn it on, but when you turn it off after a few minutes, regular stereo feels like mono. Spectacular stereo imaging, where everything feels like it has a real physical space. A true soundstage.  
 
For my money, one of the best examples of putting scientific minds to the task of describing what we hear and why we hear it, then figuring out how it could be simulated by a machine.  
 
As a postscript, I bought another one for $10 recently in a Cash Convertors, and you probably could too. Even a cheap one will do wonders.
 
7/2/2000 11:38 AM
Stephen Conner

Hi Mark,  
 
That's interesting, I'd never even heard of the Omnisonic Imager. It seems that the theory is sound as long as you are wearing headphones, and the 'L' signal goes only to the 'L' ear, etc.  
 
But once you start listening through loudspeakers, where each speaker can be heard by both ears, with associated time delays and room reflections, things get a lot more complex. In fact surely the path between the speakers and your ear holes has exactly the same delay/crosstalk effect as the Omnisonic Imager, and so the device itself is kind of superfluous.  
 
In any case, it's the recording engineer's job to deliver a mix that sounds good on an ordinary stereo. If he'd thought an Omnisonic Imager would have improved his mix, he shoud have put it through one in the studio.  
 
IMHO  
 
Steve C.
 
7/3/2000 2:37 AM
Mark Hammer
Well, I suspect that a number of the mixes that you think of as being great mixes, with terrific stereo imaging, HAVE been altered in an analogous manner to what I described, only digitally. Indeed, this stereo enhancement has shown up everywhere lately, especially in video games: Aureal 3D, Hughes SRS, Q-Sound, and a host of others I don't know the names of. All of these use algorithms for mimicking the very same "sound shadow" that the Omnisonic and the Carver "Sonic Hologram" (among others) tried to create with simple BBD's, fixed delays, and fixed filters.  
 
The effect does not rely on headphones (although it improves headphone listening), and for the most part does not depend on sitting in one specific magic spot...at least any more than regular stereo does.  
 
Since the deriving of the information to create the sound shadow depends on the original mix, some program material will sound better than others. Worst case scenarios are typically strict mono, and hard-panned stereo.  
 
Another quirk of this is that, since it creates the sound shadow by adding signal to the opposite channel, the overall amplitude of anything that is hard-panned to one channel (in the original mix) will be increased. Depending on the intensity of the effect and the original mix, turning up the effect can actually change the mix by turning up the overall level of the details (these are usually down in the mix and panned relatively hard). Finally, if you process vinyl disk with this, the disk better be in great shape, because surface noise from scratches, wear, dust, and static, tends to be.....guess what...unique to a channel. The result is that while the music sounds great, the disk sounds noisier. Perhaps this was why it never really took off commercially, since it arrived on the scene long before compact disc.  
 
On the plus side, you can listen to anything through it: radio, tape, 8-track (I still do), computers, even TV. If you process material through it, the effect is preserved to tape. One of the pluses is that you can process a tape or CD for car listening, and even if you drive a GEO or an Austin 850, the sound will seem large and unclaustrophobic. One of the 2 Omnisonics that I have actually WAS a car model for just that purpose, but you can always make tapes or burn your own CD's with it or something like it.  
 
To pursue this historical thread a bit further, the earliest processing version of this attempt to mimic how off-axis sounds are normally heard arrived with quadrophonic sound. You can go back even further to the "Hafler effect", which used an extra set of rear channel speakers, wired out of phase with the main speakers, to produce an additional distinctive channel consisting of difference signals. If you have a spare set of cheap speakers kicking around, you can try it for a cheap thrill. It works great.  
 
Here's how:  
- Identify the + and - terminal of the extra speakers.  
- Connect the + terminal of each extra speaker up to the hot/+/red terminal of your speaker connector on the back of the stereo amp.  
- Connect the -/negative/black terminals of the extra speakers up to each other.  
- Place the extra speakers behind where you would normally sit to listen.  
 
That's it. Enjoy.
 
7/3/2000 5:54 AM
Hi

I've used an Omnisonic enhancer in mixes, and they do sound much more spacious and open than the same basic mixes without. I thought it was originally a device used to process sound for motion pictures, but I could be wrong about that. It certainly doesn't make or break a good (or bad) song, but it does make the final mix sound much more nicer.  
Hi
 

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