[Russtafarian]

Hey Brian,

Have you considered preprogramming and demoing a few house curves along with neutral settings so you can show that the speakers can do either truth or fantasy?  Sometimes the truth is ugly and a little fantasy enriches the experience.

Saturday at the LA Audio Society meeting we heard Bernie Grundman talk about how he judiciously uses compression and eq to master studio recordings for CD and vinyl.  The DCX gives the listener some of that capability. 

It'd be cool to have a few preprogrammed Grundman or Hoffman patches that could be applied to recordings that had been egregiously defiled during production.

[Brian Cheney]

I think some preprogramming would be a good idea.  I plan to visit the venue in July to take some preliminary measurements and run some simulations.

I keep in mind that Albert von Schweikert did the live-vs-recorded demo at the San Remo in a similar space with excellent results.  Fact is, today's gear is equal to the task provided the music is not too complex or very dense/loud, i.e. a symphony orchestra in full cry.

We will have a max of 7 performers on stage at a time, but the Gala finale is an audience participation number where attendees will sing the choral part of Leonard Bernstein's "Wrong Note Rag".  We'll see how THAT reproduces!

[Brian Cheney]

The Problem of the Two Acoustics

Part I: Best laid plans

My first thought in setting up a "live vs recorded" demo was to have the microphones hear what the audience hears when the live musicians are playing.  To this end I considered placing the microphones in the first row of seats, suitably separated, using spaced omni mics.  My Mystery Engineer consultant comments as follows:

M.E.: It is a long extant discussion among engineers, and it is called "The Problem of the Two Acoustics".

Good listening rooms are generally held to have RT60 (reverb) times of about two thirds of a second, whereas 1.2 sec for a performance room is very dry, while a great hall like Boston is around two seconds.  A great church, 3 seconds.  The usual real-world solution to the Problem is that the usual playback room's contribution is a fraction of the ambiance of the recording.

However, if one records a small group in a smaller room such as a hotel ballroom, and the playback is to be in the same room, the fear is that if there is too much recorded ambiance in the recording (as in, recorded from within the audience space), when the recording is played back in the same room, the overlap of the transfer functions will give the game away because there is twice the ambiance of "live".

And in this regard, it is of no moment whether the recording and playback room is nearly dead--let's say, .25 sec.  Twice that is twice as much.  Twice as much of almost anything is twice as much.  The playback in that .25 sec dead room (of a recording made to capture the "usual" amount of room ambiance) will sound better, but it will sound different from "live".

Added to this is the fact that on an individual basis, almost no microphone has the same transfer function (directionality versus frequency) as a human ear, and when you are talking about stereo usage, at most there are ten mics or mic systems that intend to mimic the transfer function of the ear/brain, and most of those are mostly intended for binaural headphone playback.  Which doesn't help a loudspeaker manufacturer.

Even a (superpremium, $10,000) Schoeps Sphere (the most binaural-compatible non-binaural mic system) plopped in the first row will not sound exactly like what ears hear in the first row.  Cardioids in X/Y or ORTF, forget it, except of course, the loudspeakers also don't propagate like natural sound sources.  The goal is to land upon a mic system transfer function that when added to the speaker/room transfer function, cancels out to equal "natural".  Yeah, and I am gonna pick up Sharon Stone while she's shopping at the Home Depot!

(end of Part 1)

[Housteau]

What of the possibility of stand mounted acoustic treatments that can be rotated around 180 degrees easily, and have one side maximized for system playback and the other for the live music?  I would think that these can be home-made and still look quite professional.

[spl_nut]

The Problem of the Two Acoustics


My first thought in setting up a "live vs recorded" demo was to have the microphones hear what the audience hears when the live musicians are playing.  To this end I considered placing the microphones in the first row of seats, suitably separated, using spaced omni mics. 

My first reaction was 'what I hear here, is going to be reproduced over there? '. I have no experience with recording techniques, so my thought process may be entirely off...

Regardless, I follow this venture with great enthusiam!

 

[soarertoy]

Hi,
Might it work to:

1. Record beforehand in a dead acoustic.
or
2. Close mic to reduce ambiance, and mix for replay.

Best regards

Richard

[Hipper]

I can't add anything technical to this discussion so please pardon the impertinance, but to me it seems you should attempt to record what your listeners hear and then play through the speakers set up for nearfield listening. Whether what the listeners hear is poor or good (obviously you want good) doesn't really matter as you are merely trying to show the accuracy of your systems.

You can help control what your listeners hear during the live playing by using, amongst other things, a Behringer DEQ2496 (which is what it was designed for).

[Brian Cheney]

The Problem of the Two Acoustics

Part II: what to do

I have always used Sonex panels glued to sheets of plywood as room treatment at CES.  However, the typical St Tropez hotel room is 14x19', and we're dealing with a 28x36' ballroom in January.  Still I thought perhaps eight 4x8" Sonex panels would do the job of changing playback acoustics sufficiently so that record and playback "sum to natural".  Our Mystery Engineer replies:

M.E. The Sonex idea looks iffy, but as a matter of recording and not listening, is going to depend on two things, the patterns of the microphones and the relationships between reflection patterns, the microphone patterns, and the absorbers.

In other words if you were using ORTF micing, I'd put the absorbers along the sides, line of sight to the way the 110 degree separated mics are pointing, to knock down some of the sidewall energy--if that were the way to go.

What I'd do is try the experiment in the chorus rehearsal room (i.e. a test run in a similar undamped environment) and then on the basis of that decide whether messing with 4x8' sheets of anything is worth it.  And the other thing is that this is not the realm of small-room acoustics, where 64 square feet of RPG BAD panels can make a huge difference on the first-reflection points.  And unless the room has sheetwork walls, I question the utility.

BTW having someone else do the recording keeps the egg more off your face.

[John Casler]

It might be such that you may have to consider using TWO ROOMS.

One for Live Listening and Recording

The other for Playback

That way each room is acoustically different.

Live Room will have little treatment

Playback Room will be treated to the MAX reducing the "second room sonic overlay" as much as possible.

Is the Ballroom divisible?

[Brian Cheney]

If we had access to the Apollo Ballroom as originally planned there would have been two good and quite different spaces available.

But the Zeus is just large enough for our performers and about 30 seated listeners.  We will have to record and play back in the same space.  The question is, how best to change the acoustic (shorten reverb time) on playback?

[doug s.]

If we had access to the Apollo Ballroom as originally planned there would have been two good and quite different spaces available.

But the Zeus is just large enough for our performers and about 30 seated listeners.  We will have to record and play back in the same space.  The question is, how best to change the acoustic (shorten reverb time) on playback?

look into procuring a jvx xpa1010 dsp processor.  it allows adjustment of reverb time, based on room size/distance...

doug s.

[Brian Cheney]

Can this device reduce reverb in a recording?  If so, how does it do it?

[doug s.]

Can this device reduce reverb in a recording?  If so, how does it do it?

hi brian,

it's been so long since my ex destroyed my xp-a1010, tossing it down a flight of stairs, (don't ask - it was wery ugly - thanks to god my large subs weigh 140lbs each! ), i really do not know or remember all the ins & outs of this unit.  you want to contact ralph glasgal, or one of his associates, to find more about this unit, (and others similar), & how it works...  it is primarily designed to work on ambient surround speakers, but i think it will also work on the main speakers as well.  perhaps, if you set its playback reverb for a much longer distance between speaker-listener than the actual distance, then it might result in a perceived reduction in reverb.  unless i got it backwards...     anyways, here's a link to where you can find him.  (and a lot of other weird ambiophonics stuff.):

http://www.ambiophonics.org/index.htm

doug s.

[Brian Cheney]

Thanks Doug, I'll check it out.

AC'ers should also investigate the RPG BAD panels mentioned by our Mystery Engineer here:

www.rpginc.com/products/badpanel/index.htm

This is a 2x2ft thin panel that diffuses below the frequency where stops absorbing, and is reasonably priced and attractive.

[Brian Cheney]

If we can solve the Problem of the Two Acoustics (see the thread of the same name), then it's time to decide on what gear to record with.

While I have heard some outstanding vintage mics (including ribbons dating back to the late 1940's), I thought I would try a modern dual diaphragm phantom powered condenser mic of high quality and flat frequency response.

There are three basic typics of such mics, categorized by their directional characteristics: omnidirectional, figure 8, and cardioid (plus its subcategory of hypercardioid).  One might surmise from their names what kind of pickup pattern each exhibits.  The omni mic records equally well from all angles (there's a catch, however), the figure 8 ignores signals from both sides (also a catch here), and the cardioid pretty much rejects sound from behind, but not the front and sides (again, another catch).
Here's what my Mystery Engineer has to say:

M.E.The AKG 414 ($1kea) is an industry workhorse, but don't get the kind with EQ for vocals.  I have used 414's a lot.  The best mics, perhaps not.  414's are always the "second-best" mics at any gig, and nobody can agree what the best ones are.  BTW multi-pattern mics (414's are swtichable to all 3 patterns) are usualy less transparent than single-pattern mics.  What I'd recommend you do is start out affordable and get the single-point Audio Technica AT825 stereo mic ($349).  It is cheap because it is a fixed spread (110 degrees), fixed pattern mic.  It doesn't have switching and double diaphragms to give you variable patterns as the 414's do.  I think you will be shocked how good it is.  That you can keep and have around and always have Plan B when a fancy mic craps out.

I'd also get the Fostex FR-2LE (or Korg MR1000) portables and record your little heart out.  If either recorder works for you see about getting the software to reformat files, or just tell people that they will get their Cd's later and hire someone like Alan Silverman to transfer and master the performances.

Once you are comfortable with the AT825, some time before January see if a local Schoeps rep will rent you the Schoeps ORTF array or even the Schoeps Sphere ($10k), and see whether the improvement is worth the rental.  Or get a couple of Pearl cardioids on rental.  The are literally hundreds of valid mic choices.  I love the Crowley and Tripp ribbons--they have a budget line that includes a stereo set in a flight case for $1995, but those might be too colored for you.

For an investment of $1000 to $1500 you can have a peachy, respectable, compact portable recording setup and you might find yourself in demand locally to capture performances.  Myself I would not buy the AKG 414s unless I was going into general studio work where I'd actually use the variable patterns--most 414 owners set them to cardioid and they rust there.  My attitude is that if wide X/Y and ORTF don't work there's something wrong.

[Brian Cheney]

Well folks, I'm learning what it means to be an impresario.  Sol Hurok, look out!  Particularly since my experience in the job consists of watching Mel Brooks' "The Producers" three times.

We have a piano, the 8ft 2" Kawai SE with the LX reproducing mechanism.

We have a pianist, Chris Salocks (who posts on AA as "Chris from Lafayette"), a Stanford PhD in piano and accompaniment

We have two vocalists, Lesley Olsher (Dick's wife) who has two CD's to her credit, and Jeanine del Carlo, jazz singer and daughter of Soundguy3 (Metropolitan Opera baritone John del Carlo.)

For a bassist Lesley suggested, of all people, Stereophile editor John Atkinson.  John graciously declined but nominated George Kaye of Moscode, an excellent acoustic bass player.  We shall see how he responds.

We need a drummer.  Any ideas?

[Brian Cheney]

Note to CES attendees:

The deadline for FREE registration has been moved up this year to Nov 1.

Go to CESweb.org to register.  After Nov 1 the fee is $100!!

[Brian Cheney]

Again, word to the wise:

Early, free registration for CES ends Nov 1, afterwards it's $100.

Go to CESweb.org to register.

[Brian Cheney]

Just had my first meeting with my music director, pianist Chris Salocks, to work out what we will play for CES.

Things are complicated.  I intended to bring in a jazz bassist and sax player, but now I know that jazzers and classical players (like Chris) don't necessarily mix.  It's really two different disciplines.  I had it in my head to do the "Rhapsody in Blue" as part of our instrumental set, since it has a prominent percussion part.  Audiophiles love cymbal crashes and the RIB has them in multiples.  Trouble is, I'm going to have to play the percussion instruments myself, as our drummer has dropped out.  But I digress: there is a chasm between jazz and classical performance and I need players who are comfortable with both genres.  Also, I need a bassist who can play unamplified (no jazz bassist I've talked to would work without an amp). 

So,I called Local 369, LV musicians' union, and found a "freeway philharmonic" bassist who actually enjoys playing acoustically.  I'll likely make a baffle for him to stand in front of, to focus his mostly omnidirectional sound towards the listeners.  The man I have in mind is employed in the "Phantom of the Opera" orchestra at the Venetian and does classical and jazz equally well.  Now, the RIB has a famous opening glissando for the clarinet which requires a virtuoso player.  Found one no problem.  Except now I am paying two professionals nearly $900 each to perform over the four days (3 hours per day, equalling one "service" which is how musicians parcel out their time).

The piano I had lined up is too big to fit the available truck, and pro transport from LA would run $2400.  I will have to rent a good instrument in town which is another $1100.

I may be eating candy bar lunches for  months because of this. 

More later. 

[spl_nut]

Any 'more'?