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Haas effect Bruce Style
Old 29th August 2006
  #1
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Haas effect Bruce Style

Bruce will you please give us your word on the haas effect and using effects like stereo spread by panning the same mono sound left and right and pitching 1 up and the other down.

IM curious if you ever do this, when u do it and what you use for the application.


Thank you very much

Bryan Tyson
Old 30th August 2006
  #2
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May I first caution you!!!!!

Quote:
Originally Posted by vaesion View Post
Bruce will you please give us your word on the haas effect and using effects like stereo spread by panning the same mono sound left and right and pitching 1 up and the other down.

IM curious if you ever do this, when u do it and what you use for the application.

Thank you very much

Bryan Tyson
Bryan.....

Good topic!

HOWEVER.... I see a defiinite tendency here in folks trying too much to come up with something unique with the Nutz And Boltz of our craft and far too little effort is placed in the uniqueness of our own imagination in music recording!!!

To continue .......... - The Haas Effect

The Haas effect can be used to overcome directional masking. Haas says that, in general, echoes occurring within approximately 40ms of the direct sound become fused with the direct sound. We say that the echo becomes "one" with the direct sound, and only a loudness enhancement occurs.

A very important corollary to the Haas effect says that fusion (and loudness enhancement) will occur even if the closely-timed echo comes from a different direction than the original source. However, the brain will continue to recognize (binaurally) the location of the original sound as the proper direction of the source. The Haas effect allows nearby echoes (up to approximately 40ms delay, typically 30ms) to enhance an original sound without confusing its directionality. We can take advantage of the Haas effect to naturally and effectively convert an existing 2-channel recording to a 4-channel or surround medium. When remixing, place a discrete delay in the surround speakers to enhance and extract the original ambience from a previously recorded source! No artificial reverberator is needed if there is sufficient reverberation in the original source. Here's how it works:

Because of the Haas effect, the ear fuses the delayed with the original sound, and still perceives the direct sound as coming from the front speakers. But this does not apply to ambience--ambience will be spread, diffused between the location of the original sound and the delay (in the surround speakers). Thus, the Haas effect only works for correlated material; uncorrelated material (such as natural reverberation) is extracted, enhanced, and spreaddirectionally. Dolby laboratories calls this effect "the magic surround," for they discovered that natural reverberation was extracted to the rear speakers when a delay was applied to them. Dolby also uses an L minus R matrix to further enhance the separation. The wider the bandwidth of the surround system and the more diffuse its character, the more effective the psychoacoustic extraction of ambience to the surround speakers.

Of course there's more to the Haas effect than this simple explanation. To become proficient in using Haas in mixing, study the original papers on the various fusion effects at different delay and amplitude ratios.

May I first caution you!!!!! Something like The Haas Effect, IN NO WAY surpasses what you can add to your music mixing and recording, by developing your "SONIC PERSONALITY"!!! It should be understood, but don't think that it's a big deal in music recording!!! The Haas Effect is available to essentially everyone on the planet!! Your own "SONIC PERSONALITY" is YOURS AND YOURS ALONE!!!

Haas' Relationship to Natural Environments

We may say that the shorter echoes which occur in a natural environment (from nearby wall and floor) are correlated with the original sound, asthey have a direct relationship. The longer reverberation is uncorrelated; it is what we call the ambience of a room. Most dead recording studios havelittle or no ambient field, and the deadest studios have only a few perceptible early reflections to support and enhance the original sound.

In a good stereo recording, the early correlated room reflections are captured with their correct placement; they support the original sound, help us locate the sound source as to distance and do not interfere with left-right orientation. The later uncorrelated reflections, which we call reverberation, naturally contribute to the perception of distance, but because they are uncorrelated with the original source the reverberation does not help us locate the original source in space. This fact explains why the multitrack mixing engineer discovers that adding artificial reverberation to a dry, single-miked instrument may deteriorate the sense of location of that instrument. If the recording engineer uses stereophonic miking techniques and a liver room instead, capturing early reflections on two tracks of the multitrack, the remix engineer will need less artificial reverberation and what littlehe adds can be done convincingly.

Using Frequency Response to Simulate Depth

Another contributor to the sense of distance in a natural acoustic environment is the absorption qualities of air. As the distance from a sound source increases, the apparent high frequency response is reduced. This provides another tool which the recording engineer can use to simulate distance,as our ears have been trained to associate distance with high-frequency rolloff.

An interesting experiment is to alter a treble control while playing back a good orchestral recording.

Notice how the apparent front-to-back depth of the orchestra changes considerably as you manipulate the high frequencies.

AWWWW.... Big Deal!!!!

Bruce Swedien



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Old 6th September 2006
  #3
BoW
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Chi-Lite reflection affection

Quote:
Originally Posted by Bruce Swedien View Post
Bryan.....

We may say that the shorter echoes which occur in a natural environment (from nearby wall and floor) are correlated with the original sound, asthey have a direct relationship. The longer reverberation is uncorrelated; it is what we call the ambience of a room. Most dead recording studios havelittle or no ambient field, and the deadest studios have only a few perceptible early reflections to support and enhance the original sound.

In a good stereo recording, the early correlated room reflections are captured with their correct placement; they support the original sound, help us locate the sound source as to distance and do not interfere with left-right orientation.

Dear Bruce,

mmhh, bit like a brain-bender.

You state, in order to keep the first reflections, you use to locate the microphones away from the singer or the instrument in order to keep as much directional information as possible.

Here is, how I understand it:

Let’s say, I’m in the middle of a square room with the dimensions 34 Metres (~100 feet) x 34 Metres x 16 Metres (~50 feet) high.

If I clap my hands, I’m able to detect my relative spatial position as in the middle because the sound energy of the first reflections arrives to my ears at the same out of either direction within 100 milliseconds, right?

If I move to the side of the room, the ratios of the back-bouncing wavefronts will vary in relation to my position. If I for instance move 8,5 Meters (25 feet) to the side and clap again, the first reflection bouncing back from one sidewall arrives in 150 ms, from the other in 50 ms.
If I was blindfolded I could with a little conditioning determine my position in the room by listening to the first reflection and reflective patterns. This is easily possible in a cubic shaped environment.

Recording studios are often built in trapezoid shape, like Westlake, on order to avoid shatter-echoes and standing waves. Even more, the walls are not plain, but sloped to act as ‘wavebreakers’ in order to get a more diffuse soundfield. To my understanding, you can’t really speak about correlated reflections at all, here.

Never the less you always refer to the studio as one of your preferred locations. So, where does a “live” studio end and a “dead” studio begin? (b.t.w.: I’ve got another post running about studio design)

If I resume your recording techniques; when you capture audio while using tube traps, you even reduce the spatial information of the recording-room.
So, bottom-line, as far as I understand, there is only very few directional information from to catch in for the little poor microphones in recording environments like Westlake.

On another picture, I saw you recording an orchestra (it was about those DECCA-tree, you were using). The room seems cubic shaped, like Abbey Road, for instance. So is that statement of you only true for or in certain acoustical environments?

I’ve been listening to the Chi-Lites “Oh Girl”, where the mouth organ and the lead vocal appear quite distant; the reflections (panned extreme left-right) seem to have a significant delay to the direct signals which appear both in the center. Did you delay the reverb (the famous 125 ms) for the reason to keep up the early reflections of the recording environment, that I assume was built not in trapezodial shape?

Could you explain?

Very appreciated: Boris

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