johnnie225
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Sound reflection in rooms
Kal Rubinson
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In a podcast at UltimateAV recently, JA stated that loudspeakers would have to be the same shape of the instrument they're reproducing for it to have correct fidelity. But most of the music we listen to is a *blend* of instruments whose soundwaves cancel each other out.

On a purely logical level, JA's contention is questionable. OTOH, until I can actually read what he said, I will not comment further.


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I don't doubt for a *solo* instrument the shape of speakers might matter...but thankfully, most of us are exempt from this situation.

Even for a solo instrument, there are issues.

Kal

Jan Vigne
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http://www.canuckaudiomart.com/details/159518-yamaha_ns10_speakers_the_ear_shaped_ones_/

http://www.stereophile.com/audaciousaudio/105sonus/


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Yamaha once made a loudspeaker shaped like an ear.

Elk
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I haven't heard the podcast so I cannot comment specifically.

Certainly a speaker that radiates sound precisely as the original instrument would sound like that instrument, everything else being equal.

Unfortunately, we don't have a way to record the entire soundfield of any instrument. Thus if we even had the speaker we wouldn't have something to play on it.


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The same goes for piano - is it affected by the shape of its soundboard?


Yes. It is one of of many reasons that a baby grand has a different sound than a nine foot concert grand. Similarly the precise placement, size and shape of a violin f-hole makes a significant difference.

I like your question regarding the shape of an electric piano. It wouldn't be of a piano, but there would be an appropriate "acoustic shape" of some sort.

Great topic.

Kal Rubinson
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I haven't heard the podcast so I cannot comment specifically.

Nor can I but............


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Certainly a speaker that radiates sound precisely as the original instrument would sound like that instrument, everything else being equal.

.........that's the logical issue. You would have to record the instrument without the effects that the shape has on the sound in order not to make those effects redundant when reproduced by a similarly-shaped speaker.

Kal

Elk
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You would have to record the instrument without the effects that the shape has on the sound in order not to make those effects redundant when reproduced by a similarly-shaped speaker.


Excellent point.

johnnie225
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Great point. And this gets to the heart of the "reflection" issue. If we are capturing reflections in the air, then all we have to do is *reproduce* those accurately at home. It's probably not a good idea to launch the sound forward-only - Linkwitz swears by dipole radiation, while others say we need surround processors (like Lexicon, which J. Gordon Holt was fond of). And only *then* for classical music. Do we need surround processing for jazz trios ?

geoffkait
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Steel Rails Under Thundering Skies (Bainbridge), one of the most remarkable recordings of the 20th century, also available on CD, contains sounds of various steam locomotives, including horns, the maniacal clickety-clack of locomotives on steel tracks, thunderstorms with heavy downpours, the mechanical noise of loading operations, voices of linemen, etc. Now that I think about it, my speakers did look like boxcars.

Kal Rubinson
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Quote:
Great point. And this gets to the heart of the "reflection" issue. If we are capturing reflections in the air, then all we have to do is *reproduce* those accurately at home. It's probably not a good idea to launch the sound forward-only - Linkwitz swears by dipole radiation, while others say we need surround processors (like Lexicon, which J. Gordon Holt was fond of). And only *then* for classical music. Do we need surround processing for jazz trios ?

Nope. We need multichannel recordings for this.

Kal

Jim Tavegia
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I have found that with my last 2 recordings that I slightly prefer listening on headphones to take my rooms out of the equation. Unfortunately, that is not how most people listen so care must be taken to capture the sound for that format. Using omni mics as I did does create issues, but also can provide a great sense of the room depending upon how far back from the ensemble you set up.

I am sure as JA states that adding the playback reflections to the recorded reflections for the audience to experience would have not sounded right at all and made the live sound vs. recorded sound experiment very hard to enjoy or think of as "real".

I have enjoyed rereading JA's K622 article in the archives as an education as to how Tony Faulkner set up that recording session with his omni spacing and height. The photos were priceless.

johnnie225
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"We need multichannel recordings for this"

There's nothing wrong with Trifield...which is a huge step up in reality, as reported by several audio writers. But never heeded by audiophiles....

ncdrawl
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You should Try Jecklin Disc, Jim T..

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"We need multichannel recordings for this"

There's nothing wrong with Trifield...which is a huge step up in reality, as reported by several audio writers. But never heeded by audiophiles....

piss on m-ch. a badly executed gimmick. stereo for life

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Quote:

Quote:
"We need multichannel recordings for this"

There's nothing wrong with Trifield...which is a huge step up in reality, as reported by several audio writers. But never heeded by audiophiles....

piss on m-ch. a badly executed gimmick. stereo for life

Sorry, but experience proves you wrong. It is possible to do really good multichannel, at least as far as John Atkinson and Wes Phillips were concerned. (and some others)

But you don't do it the way most are produced. (rolls eyes)

Elk
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It is possible to do really good multichannel


Yes!

Good multi-channel played back on a properly setup system is great.

Sadly many recordings are gimmicky and few systems seem to either be capable of good multi-channel playback or are setup poorly. (Of course, many stereo systems are not set up well - muti-channel just makes this worse.

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Quote:

Quote:
It is possible to do really good multichannel


Yes!

Good multi-channel played back on a properly setup system is great.

Sadly many recordings are gimmicky and few systems seem to either be capable of good multi-channel playback or are setup poorly. (Of course, many stereo systems are not set up well - muti-channel just makes this worse.

Yup, the right five chicks may be superior to two, but they often aren't. There is excess cost to consider, and resources must be divided amongst more 'channels.' It's OK as a gimmick, but I'm happy with the set-up I've got, being able to focus on just two channels of higher quality devices.

If I want multi-channel, I'll go to the Imax and watch Expedition Everest.

rvance
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If I want multi-channel, I'll go to the Imax and watch Expedition Everest.

If I want multi-channel, or vinyl...or mono Beatles cd's, I just turn on the hi-fi. And it is glorious.

Kal Rubinson
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There is excess cost to consider, and resources must be divided amongst more 'channels.'

That much I will concede.

Kal

johnnie225
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Actually, with multi-channel, we can use lower-cost speakers because there's less demand on each one (in terms of soundstaging, SPLs, etc). The cost kicks-in with surround processors which are not cheap. But some of these come with DACs and attenuators (and in the case of Meridian, very *good* DACs and attenuators). So what are we saying ? Is it more expensive..or just more $$ upfront ?

The (American) creators of stereo, golden-age recording engineers of the 1950s and recent-decade pyscho-acoustic research says that a center speaker (identical to L/R) is needed to properly reproduce centrally-located sources.

BTW: it wasn't Blumlein (Kal) - his experiments w/ stereo were in two-channel, with demo speakers aggressively towed-in. Even Blumlein wasn't perfect. More famous for his mike techniques and disc-cutting measures, not multi-channel reproduction.

mrlowry
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Paul Klipsch was a big proponent of three speakers for stereo reproduction.

Jan Vigne
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Paul Klipsch was a big proponent of three speakers for stereo reproduction.

He got to sell more speakers and name one after his wife.

(No, not the Heresy, the Belle!)

And to think, some people made fun of PWK.

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Paul Klipsch was a big proponent of three speakers for stereo reproduction.

I have an old McIntosh C-28 preamp with a center channel configuration...it's OK...a fun sonic toy. If speaker placement makes center fill anemic, this can add significant benefit.

That baby has everything. Two sets of stereo outputs and two 'center channel' outputs. It was great for using stacked speakers or if you wanted to biamp directly without crossovers - if one were so inclined!

For Klipsch, I always thought the corner horns had some center fill weakness...the chance to put a La Scala in the middle may have been the bomb!

Kal Rubinson
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For Klipsch, I always thought the corner horns had some center fill weakness...the chance to put a La Scala in the middle may have been the bomb!

I remember that I was fortunate to hear such a setup hosted by PWK himself. Unfortunately, I was too young and insensitive to appreciate it at the time.

If I only knew then what I know now.......................

Kal

bertdw
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I would have thought the speakers sensitive enough for the both of you.

Jim Tavegia
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I recorded Temple High School Band's final concert for 2010 using ORTF and did not care for the recording with angular spacing with capsules 10" apart. I did not have a Jecklin disc to try so that will tried this summer.

I still prefer my 7-8ft spaced omnis, but will continue to experiment with this mic placement to find the sweetspot for the rooms I will be working in. There are a number of DIY Jecklin disc projects to consider.

Thanks for the tip.

Jim

Elk
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I need to play with Jecklin disc again as well.

Unfortunately the commercial variants are pricey and the home made jobbies would take a bit more time than I currently have available.

You can get both great sound and wonderful imaging with this setup.

Jim Tavegia
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The biggest problem with recording for school is totally the venue...the cafeteria cement block walls and tile floor; the gym with nothing but hard surfaces. The best recordings I made with them were at our church that seats 1400 and is acoustically very nice with 35 foot ceilings, carpet, angles galore, huge stage with no side walls within 20 feet either side.

It would be nice to find an affordable Jecklin disc.

Elk
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At the school I would stay away from omnis in any configuration as you don't want to listen to the room.

I would start with XY coincident. This minimizes ambiance, but will provide a nice image.

Tough space to work in.

Jim Tavegia
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I ues uni capsules Thurs nite, spaced 10" at 90 degrees up about 8+ feet, 8 feet back from the band...as far as I could go as the audience was very close. Recorded on my Sony DAT as my Dell laptop is getting a new (used) mother board.

I had not used my rebuilt desktop for recording. I have found the Behringer FCA 202 in my playback and recording rounting, and it playsback fine, but in recording in Sony Sound Forge it will only record from internal files either already inputed from WMP or from tracks ripped by Sound Forge and it will record them in real time as they are playing.No other inputs work including the motherboard line in.

My Win Media Vol control only has WAVE, CD, Synth controls as the line in and Mic do not appear from my fresh win XP install. There is no other mixer controls with the Behringer FCA202. More trouble shooting to do.

The unit worked fine in my laptop. I just prefered the Echo as it can also do 88.2 recording.

Elk
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"Uni" is what? Cardioid?

How did you come up with 90 degrees at 10"? Did you try ORTF or NOS?

Sound Forge should record any input (as I bet you know) but setting up I/O can be tricky sometimes.

88.2 is great to save a little space, but the quality of SRC is now so high I wouldn't hesitate to record at 96 evin if you are typically going to resample at 44.1.

If you version of Sound Foprge is new enough to incldue iZotope's 64-bit SRC be sure to use it. It takes a lot of CPU crunching but is quite nice.

r8brain is a wonderful free SRC: r8brain

Jim Tavegia
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Yes uni is cardioid, as I do not have any "hyper" mics. From the stereophonic zoom the measure is 20-25cm at 70-90 degrees plus/minus 50 which if any wider would have had the "beam" of the uni at the edges of the band's positions left and right. I probably could have gone narrower, but that position cut evenly through the band left and right on an angle. Tighter angles and I would have gone right over the heads of the interior rows left and right of flutes and french horns on the right and clarinets on the left. I will admit that I did not agonize of this concert that was all of 23 minutes. The edges of the band were within 6 feet of a side wall. The drums in the rear were 8 feet from the back wall with 16 foot ceilings of 2x2 suspended tiles.

I repostioned my speakers in my man-cave to better adjust the sound field and it sounded better today. The cafeteria with all the hard surfaces is just the wrong place to do anything other than "each a school lunch", and not much else.

I've helping my son move his family into a new house so I am beat. I never realized how much I hate moving. Maybe when I was 30 and in great shape it didn't matter, but at near 63 suff hurts already without doing it on purpose.

Elk
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Got it. Makes sense.

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