a reverb technology primer

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Re: a reverb technology primer

Post by øøøøøøø » Thu Jun 22, 2017 1:11 pm

shadowplay wrote:
øøøøøøø wrote:
I really wanted to touch on this in the article, but I figured only a few people would read 5,000 words about reverb. So I narrowed my scope.

Another early reverb pioneer was Bob Fine on the "Mercury Living Presence" classical records of the early 1950s. He chose Schoeps microphones in part because their increased sensitivity and "reach" allowed them to be placed a bit further back in the hall, picking up more of the hall's ambience. He tried other things, like sending a signal off the tape machine's repro head to a speaker in the back of the hall to get more ambience/reflection in the mic.

Nowadays, classical records often use multi-mic arrays with mics positioned in the back of the hall for added ambience.

I was supposed to be involved with the recording recently of a suite of pieces that were written specifically to exploit the use of the acoustic characteristics of the respective insides of a series of enormous scupltures upstate. But I think the project lost funding (or had trouble securing permission? dont remember) and stalled. But there were weird reverb characteristics inside these giant walk-in sculptures, and a composer friend wrote pieces to exploit the unique character of each one (or was in the process of writing)

Ah interesting, I've been aware of project like the one you mentioned over the years like ones by David Toop and Max Eastley or recording in specific ambient spaces like Saxjag mentions, like for example Dreams Less Sweet recorded in the hellfire caves and reproduced using Zuccarelli Holophonic systems.

I'm still curious about actual notation to simulate echo (like Emika was shooting for) or even score notes pointing towards the sort of ambient space a piece is to be performed in. I imagine this would go right back to our ancestors taking their hollow log into a specific cave to get the repeats as they banged it. This is touched on in the absolutely brilliant BBC Radio series Noise: A Human History which is a genuinely fascinating series about humankinds relationship with sound. Sadly it's no longer free to stream but there are some clips here and you can get thewhole thing on itunes and possibly elsewhere for less, though even at itunes prices it's good value since it's 8 hours of material.

D
To an extent this has ALWAYS been a part of composition, whether conscious or subconscious.

Like-- a Palestrina mass relies upon the acoustics of a cathedral for its effect. It wouldn't AT ALL be the same piece of music if it were sung by the same choir jammed into a 25 square meter room with a 2m ceiling height. Palestrina, whether conscious or not, was composing for the medium-- which was not "a group of human voices," but rather "a group of human voices in a giant, cavernous stone acoustic environment."

Likewise/conversely, bebop in the 1940s developed in small clubs like Minton's in Harlem, and somewhat later, a few places on 52nd St. in midtown Manhattan. Highly rhythmic, syncopated music at tempos upwards of 400 BPM simply does not work very well in a concert hall designed for orchestral performances (anyone who's ever been to a concert by visiting jazz artists held in a University's concert hall surely knows). Things get muddy and indistinct.

Really, any music that's been around long enough to develop a "tradition" will reflect, within the conventions inherent in that tradition, the type of acoustic environment in which that music is typically performed (or originated).

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Re: a reverb technology primer

Post by saxjag » Thu Jun 22, 2017 1:24 pm

MrShake wrote:...classical-era composers writing pieces specifically based around a specific's concert hall's unique reverberant characteristics (i.e., not to be performed just anywhere the charts may travel). What's the history of composers crafting specific music and "playing" specific architecture...?
Couldn't tell you exactly when, but musician's guilds in European towns established unique localized tunings to which instruments made & played locally had to conform. Possibly this was to prevent mendicant musicians from coming to town and stealing gigs. Inevitably each town's musical ensembles had to perform in local structures -- whether church, guild hall, or tavern. Bigger towns would, I imagine, have bigger spaces which would generate more complex reverberations.

Indonesian gamelan ensembles each have unique reference pitches. All the instruments of a gamelan orchestra are built and tuned together -- you can't mix & match instruments from two different ensembles. Gamelan orchestras do play in the open air -- possibly inside temples and/or palaces as well, but I'm not sure. Traditionally, I believe, each ensemble was associated with a specific local ruler.

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Re: a reverb technology primer

Post by øøøøøøø » Thu Jun 22, 2017 1:34 pm

MrShake wrote: What's the history of composers crafting specific music and "playing" specific architecture the way we quibble over algorithms in different circuits?
The history is long indeed.

Several medieval churches in Sweden and Denmark had pots of ash embedded in the walls which served as Helmholtz resonators. In some of them, ash was placed to serve as a dissipative agent. The notion of composition and acoustical engineering working hand in hand with intent is very old indeed. Probably MUCH older than that, in truth.

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Re: a reverb technology primer

Post by saxjag » Thu Jun 22, 2017 1:54 pm

øøøøøøø wrote:Several medieval churches in Sweden and Denmark had pots of ash embedded in the walls which served as Helmholtz resonators.
Which is particularly remarkable when you consider that Hermann von Helmholtz wouldn't be born until 1821. So those medieval architects weren't just acoustically savvy, they had the gift of prophecy as well.

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Re: a reverb technology primer

Post by treblemaker » Thu Jun 22, 2017 1:56 pm

Cool article. Thanks for sharing!

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Re: a reverb technology primer

Post by shadowplay » Fri Jun 23, 2017 1:20 am

I found this article from a UK newspaper that touches on some areas relevant to some of the recent posts in this thread.

CLASSICAL MUSIC / Now you hear it, now you don't: The echo has sounded through music since the Renaissance and before. Bayan Northcott considers the pleasures of reverberation

D
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Re: a reverb technology primer

Post by øøøøøøø » Fri Jun 23, 2017 5:05 am

saxjag wrote:
øøøøøøø wrote:Several medieval churches in Sweden and Denmark had pots of ash embedded in the walls which served as Helmholtz resonators.
Which is particularly remarkable when you consider that Hermann von Helmholtz wouldn't be born until 1821. So those medieval architects weren't just acoustically savvy, they had the gift of prophecy as well.
Not prophecy. They just made discoveries that were also discovered and codified and written down by someone else, somewhere else, much later.

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Re: a reverb technology primer

Post by antisymmetric » Fri Jun 23, 2017 12:44 pm

:-* This thread is just completely fascinating- thanks for kicking it off, Brad.
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Re: a reverb technology primer

Post by saxjag » Fri Jun 23, 2017 4:25 pm

øøøøøøø wrote:
saxjag wrote:
øøøøøøø wrote:Several medieval churches in Sweden and Denmark had pots of ash embedded in the walls which served as Helmholtz resonators.
Which is particularly remarkable when you consider that Hermann von Helmholtz wouldn't be born until 1821. So those medieval architects weren't just acoustically savvy, they had the gift of prophecy as well.
Not prophecy. They just made discoveries that were also discovered and codified and written down by someone else, somewhere else, much later.
Y'know that feeling when you make a joke & somebody takes it seriously & tells you that what you said is illogical & wrong? Amazingly, Hermann von Helmholtz, 'way back in 1847, predicted that I would be having that feeling right about now. I'm still reverberating from the shock.

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Re: a reverb technology primer

Post by sessylU » Fri Jun 23, 2017 5:10 pm

saxjag wrote:
MrShake wrote:...classical-era composers writing pieces specifically based around a specific's concert hall's unique reverberant characteristics (i.e., not to be performed just anywhere the charts may travel). What's the history of composers crafting specific music and "playing" specific architecture...?
Couldn't tell you exactly when, but musician's guilds in European towns established unique localized tunings to which instruments made & played locally had to conform. Possibly this was to prevent mendicant musicians from coming to town and stealing gigs. Inevitably each town's musical ensembles had to perform in local structures -- whether church, guild hall, or tavern. Bigger towns would, I imagine, have bigger spaces which would generate more complex reverberations.

Indonesian gamelan ensembles each have unique reference pitches. All the instruments of a gamelan orchestra are built and tuned together -- you can't mix & match instruments from two different ensembles. Gamelan orchestras do play in the open air -- possibly inside temples and/or palaces as well, but I'm not sure. Traditionally, I believe, each ensemble was associated with a specific local ruler.
Would love to hear more about this. European instruments were tempered in various different ways, and according to regional fashions. It hadn't occurred to me that this would have an impact on concert halls.

Gamelan instruments (my knowledge is a but shaky here), I had always understood that the instruments were considered sacred, so once an orchestra or instrument was placed, it could not be moved. Also, they shouldn't be stepped over, because there's some link to the gods in the sky? My knowledge here is pretty anecdotal. My understanding was that if it didn't conform to the above, then it wasn't a Gamelan, it was just some instruments from that region. Considering all that (if it's true), it would make sense that orchestras are unique with their own pitches and temperaments.
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Re: a reverb technology primer

Post by saxjag » Fri Jun 23, 2017 9:49 pm

AFAIK, your info about gamelan instruments (being sacred & not to be stepped over) is correct. Wouldn't it be great if everybody felt that way about every instrument? Wish I had a dollar for every drunken wedding guest who tried to manhandle my saxes. & you can never just kick them off the bandstand, can you, 'coz they always turn out to be the bride's uncle.

Back to the topic: It actually makes sense historically for each town to have had its own unique reference pitches. How could it be otherwise in times when communities were relatively isolated or when neighboring regions were at war? We take for granted the presumption that empirical measurements of standard units are replicable anywhere on the globe, but that idea only gained currency in the Enlightenment -- at least in Europe. (It wouldn't surprise me to learn that standardized measurements existed earlier in Imperial Japan, say, or China.)

In other words, the ability to agree on a standard reference pitch for all instruments requires the existence of large cities in unified, hierarchically governed nation-states which are not only at peace with one another, but also possess safe roads, open markets, efficient communications, skilled craftspeople, & transferable technology. For most of human history, such conditions have been scarce.

OMT: Many grand old medieval & Renaissance cathedrals contained multiple chapels within their large open floor plan. So the interior spaces not only had to be reverberant, they also had to provide some degree of acoustic isolation for several priests or preachers haranguing multiple audiences simultaneously. I agree that the architects must have had substantial knowledge of acoustic principles, whether derived from empirical measurement or from intuition based on experience.

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Re: a reverb technology primer

Post by sessylU » Sat Jun 24, 2017 4:10 am

saxjag wrote: OMT: Many grand old medieval & Renaissance cathedrals contained multiple chapels within their large open floor plan. So the interior spaces not only had to be reverberant, they also had to provide some degree of acoustic isolation for several priests or preachers haranguing multiple audiences simultaneously. I agree that the architects must have had substantial knowledge of acoustic principles, whether derived from empirical measurement or from intuition based on experience.

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I had a conversation with a colleague recently about this, we were talking about certain halls and churches sounding so good, I likened those acoustic/architectural designs as being like the PA systems of their day.

It's one of the reasons I like going to cathedrals to have a look around. In Exeter, where I am we're lucky enough to have a really good cathedral for concerts, with an incredible pipe organ. It makes you realise that the pipe organs in those cathedrals, they were the most technologically advanced and complex structures around, and they were the things that communities and cities poured all their resources into over the course of a few generations. They were the space shuttles of their day, and that always fills me with awe a bit. Especially when they're still being used, and they're still incredible.
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Re: a reverb technology primer

Post by øøøøøøø » Sat Jun 24, 2017 8:21 am

Yes! And those pipe organs and the acoustic spaces they inhabit were, in some sense, one and the same-- the structure was part of the organ's tone-producing "system," and the organ itself was part of the structure.

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Re: a reverb technology primer

Post by saxjag » Sat Jun 24, 2017 9:09 am

& when the pipe organ got smaller & went electric & left the cathedral for homes & storefront churches, the psychological need to experience that gigantic, numinous architectural echo led to the development of the reverb tank.

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Re: a reverb technology primer

Post by saxjag » Sat Jun 24, 2017 9:25 am

I was once hanging out with my brother the sound engineer in an empty moviehouse, one of those great old halls from before the era when cinemas got subdivided into multiplexes. The house sound system was on but not playing any audio content, so an ambient hum was faintly audible as background noise. My brother explained to me the concept of nodes, & said it was theoretically possible to mathematically plot the locations where echoing sound waves would converge or cancel out.

I was incredulous, so he invited me to choose seats at random & listen. Sure enough, in some seats the hum was loud & annoying, like my head was inside a hive of bees. And in other seats there was silence.

Shrink that movie theater down to the size of an amp & you can see why determining cabinet dimensions is something of an art.

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