I'd like some input regarding digital and analog recording.

[Zut8083]

Holy Mackerel!  I gotta get some books, and THAT'S A LOT OF COOL STUFF YOU LISTED!!  SHAZBAT!  And as described, it all serves a purpose/the song.  Very cool!  Thanks guys!

[cozmik_cowboy]

And for sound in general, you could do a lot worse than starting with Harry F. Olson's Acoustical Engineering (1939).


Peter

[tbrannon]

I learn so much on this forum.  Thanks to everyone who contributes knowledge and experience!

[Zut8083]

All of these titles being proffered as classic sources to read to learn how recording is done is very exciting, indeed.  Thanks to all!

[Zut8083]

OK, so I have another wacky question about the design of recording spaces/performance venues.  I have read that the human ear can hear sound reliably and on average down to around 20Hz, or a 56 ft wavelength.  To focus sound at this frequency, based on parabolic focusing, you would need a large room-sized receiver to direct that sound to a single point.

These wavelengths will not cover the rest of the sound spectrum as they have different receiver diameters to focus different frequencies of sound, and then that is only to one point.  How do some venues emphasize different frequencies that make them sound warm and inviting?  It doesn't seem that any parabolic reflection technology would work very well, thus, how would a PA work with the internal shape of a venue to provide a highly regarded reflection/augmentation of the sound so that the band sounded extra good?

This may be a little convoluted or tangled, but I guess this falls under how to augment the sound of instrument/amplification so that the listener's ears are in for a really amazing experience?  I am sure there is no one answer, or maybe even and answer other than copying serendipity as people have different tastes.  I am just curious if anything like this, the designing of venues to bounce preferred frequencies to audiences to give a permanent and hopefully pleasing parametric eq., is done during engineer or is a common practice.  Thanks.

[elwoodblue]

  I've heard of clubs reversing one of every few subs near a stage to create a reinforcing in-phase wave
against the back wall,
 I'll have to search my memory (or google) to remember what that's called.

[Zut8083]

Is it "Constructive Interference", maybe?  I dunno the proper term, but that's a really cool PA tool to hear about.  I thought I had heard that some specialized acoustic music venues exist (i.e. for classical and jazz fare ONLY), both domestically and abroad, that are built to emphasize certain resonant tones for performances.  I am just unsure how to tune the venue or tune the venue, its environment, and the audience for different performances, or if that's ridiculous.

[mario_farufyno]

Zut, a perfect room in terms of acoustics should have to balance the way sounds will be heard there. Ideally it will be flat, in the sense that it will not colorate or modify what tones instruments and loudspeakers are generating. So it has to have at least one perfect spot where it is "transparent" to your ears and "true" to sound sources.

That way you can be sure that what you hear is what you'll get recorded. Despite there is no easy way to get perfect rooms and is probably impossible to get a 100% flat sweetspot, there are ways to improve monitoring rooms. Check this guy, great teacher and explains all the subjects:
https://www.youtube.com/channel/UCu6Bjebk4fuye46VRG5Y83A

[mario_farufyno]

In a flat room (or near to it) you can choose wich frequencies to enhance and do it easily with eq. In an uncontroled room you may have to spend your eqs to tame down problems instead to construct something good. Rooms that enhance part of the spectrum can make a good sounding records seems to bias towards that region. If you monitor a recording in such enviroment, you risk thinking that you need to compensate something that is really not there, like trying to paint a colorfull landscape wearing color lens glasses.

[mario_farufyno]

Check when he talks about Room Modes.

I was in the mood to explain it, but I really can't express my self in english as easily as I wish to, so forgive me. The Acoustic Fields I suggested is a great source, hope it'll help you. Email me if you wish.

[mario_farufyno]

Think Room Modes like harmonics nodes in a vibrating string. So the problem is that some places will enhance some frequency and other spots will kill it. More, if you think about harmonic series, you know that some frequencies will be enhanced, some will be damped and some will be not affected. That is what defines your guitar tone (combined to the way woods and construction decisions will affect how this ressonates in body and neck) and thats how rooms have natural tones, too.

The problem starts when the color is such strong that dramaticaly changes how sounds are heard there.

As in string, harmonics happens along its phisical extension, and that happens along one room dimension too. So you can expect one specific frequency being loud in some spots alng the room while missing in others. To make things harder, rooms are tridimensional, but this can be a solution too.

The problem gets nasty when 2 or 3 room dimensions are equal or almost. This superimpose harmonic nodes and make the problem worst but this also means that if you balance better room proportions, those harmonic series can complement one another, spreading along sound spectrum instead of pinpointing just specific frequencies. Cubic rooms are bad but if it has complementary dimensions the room can sound full and open at same time.

[mario_farufyno]

What is made in opera houses and theaters is using sound absorption to control reverberation.

If it is an auditorium and the goal is speech clearness, we tend to put reverb time down. Depends on room size (bigger the room, more reverberation is acceptable), but we reach for reverberation time near 500ms to 1KHz and shorter below 200Hz (to avoid boominess).

In classical music facilities we use longer reverberation times to glue all orquestral elements and let the lows below 200Hz to reverberate even longer. This is a strategy to help acoustic instruments to sound deeper and punchier to audience, and works just when the room doesn't have Modal problems (you don't want a rumble sounding room).

In electric music context, the lows are usualy overpowering yet, so we don't really need more lows driven by room. Rooms like that ends being described as boomy. Our natural enviroment are garages or home rooms, so matches better shorter reverb times and hopefully windows and closets get the lows out of sight at home (worst to neighbours but better to players in our own house).

[Zut8083]

Thanks, Mario!  I am not very familiar with designing venues for even, natural sound response.
 I do remember that Phil Lesh added an anecdote in his autobiography to describe the addition of a white noise generator and receivers from their sound system to pulse the venue and look for high, middle, or low frequency responsiveness or ablation.  This then informed the tuning of the PA, accordingly.  He also noted that is now pretty common practice with PAs, but what you've described bears further, careful study.  Thank you, again for your insight.

[cozmik_cowboy]

Very few rooms are acoustically flat - and the variation from flat that is ideal for a string quartet won't work for a swing band, etc.  Buy every room can be tuned for your needs; I've always said that the soundman's most critical tool (other than his ears) is the graphic equalizer.
White noise generators & RTAs were just breaking into the highest-priced echelons of reinforcement when I left the trade as full-time matter; I knew of, and lusted after, them, but have never encountered them.  I had the person whose voice I was most familiar with talk in a conversational manner into a mic & EQed the room so that it sounded like they were sitting next to me chatting.  Works every time.

Peter

[Zut8083]

Peter-

I really like that approach.  That's really cool.  The second worst EQ in a live act that I heard was Blues Traveler in Wrigleyville in...2000?  The soundman must have been on serious expired milk, because the treble was all the way in the back and the bass was all the way forward, and this was a small gig in a 500 seat capacity club near a burrito joint.  I don't know why the bass was all the way in the front, as I would assume it would really cause problems with the monitors as I don't think In-Ears were a big deal for everyone in a band at that point.  Not even Blues Traveler.  Thanks!

Cheers,
Zut