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To hear in phase and time aligned music, wouldn't the source material have to be in phase and time aligned?


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Recordings CAN introduce phase issues. Speaker CAN introduce phase issues. Phase issues from Recordings AND Speakers CAN compound to exponentially make things worse (I think!). Having phase/time aligned speakers removes phase issues from the speakers, and therefore prevents exponentially compounded phase issues regardless of whether a recording is phase coherent. (This is predicated on phasing issues compounding! I am not so confident on this point, but it seems intuitive that peaks and troughs can double or cancel, and therefore potentially adding a third peak or trough via phase issues could further ad or subtract another 3db!)

That would suggest yes, absolutely, BOTH phase coherent AND phase troubled recordings will sound better on Vandersteens, with phase coherent recordings sounding even that much better.

 

 

 

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Agreed, it takes the speakers (Vandersteens) out of the possibility of changing things.

Any mixing boards that add or subtract from the "live" event add phase changes. 

Sheffield Sound Lab recordings, being direct to disc, do sound GREAT. 

 

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28 minutes ago, GdnrBob said:

Hmm, interesting question...

I would imagine a live recording would be time and phase aligned, but a studio recording with multi-tracks might be a different story.

Bob

 

""Phase is not a property of just one... signal but instead involves the relationship between two or more signals that share the same frequency. The phase involves the relationship between the position of the amplitude crests and troughs of two waveforms.

Phase can be measured in distance, time, or degrees. If the peaks of two signals with the same frequency are in exact alignment at the same time, they are said to be in phase. Conversely, if the peaks of two signals with the same frequency are not in exact alignment at the same time, they are said to be out of phase." - The CWNA definition of Phase v106"

I think you are correct about live recordings. The laws of physics dictate that time/distance/phase are coupled together, while amplitude is entirely independent. So even changing the amplitude/volume of a single take track at certain frequencies and not others will not allow phasing issues to be created.

But alas, I am a dummy and what i have said above seems suspect because I cant understand even the basics of how two instruments playing the same note at the same time can be in phase. Lets use 5000 cycles per second as an example, and the definition "peaks of two signals with the same frequency are in exact alignment at the same time". Well, if a cycle is 1/5000th of a second, a 1/4 cycle out of phase represents 1/20,000th of a second off! an 1/8th represents 1/40,000th of a second! How can a note played on two trumpets sync on a timescale of tens of thousands of a second?

Are musical vibrations like clock pendulums that will sync their cycles/vibrations/swings over time into perfect phase synchronicity?

Maybe the official line that Phase only matters on the attack (A) portion of ASRD is more correct than us Vandersteen lovers like to admit? (but that Timing is still everything, even if phase is out when it comes to the SRD portion?)

Come to think of it, it beggars belief that the human ear can hear phase at all!

 

 

 

 

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3 hours ago, GdnrBob said:

Hmm, interesting question...

I would imagine a live recording would be time and phase aligned, but a studio recording with multi-tracks might be a different story.

Bob

 

I think we need to make sure we don't get into the weeds about "Time and Phase Correct" speakers.  On the recording side engineers play with the mix, phase and time (good example Pink Floyd) but this is "Art".  An electric lead guitar with tubes driven into hard distortion and reproduced by a 12-inch paper woofer with a large aluminum dust cap is "Art" certainly not low distortion.

On the reproduction side the entire system needs to be "Time and Phase Correct" to have a chance to hear the "Art" as the engineer intended.  If we don't like it, we could modify the "Art" with tone controls, reverberation right left phase manipulation for ambience, etc.  I believe "Art" has creeped into the playback over the years determined in part by what music the listener likes especially speakers.  I have seen a convergence over the years of phono cartridges, tube amps don't sound slow with rolled off plump bass anymore and solid state is not harsh and bright.  On the other hand, if you go to a show the sound of speakers is all over the map.  I am not so prude that if I discovered an error or inaccuracy to put into our speakers that served all music positively, I might do it.  45 years and I am still looking.  RV

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3 hours ago, DC-93 said:

Ahhhh!!!  But is your source material coherent? 😁

It is what the title asks.

But I think a  mic is phase and time aligned. Maybe some small group delay could exist, but I doubt it.
And the electronics are largely linear and aligned to many kHz if not hundreds of kHz.

The biggest phase and time shifters are the cabinet and the XO, which are probably by orders of magnitude larger than anything else, except maybe a phono cart??
(IME)

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8 hours ago, DC-93 said:

Ahhhh!!!  But is your source material coherent? 😁

Yes, that was the question.

Would a recording of something in complete time and phase coherency sound better with our speakers? My take is that something recorded live should be time/phase coherent as it isn't open to as much manipulation as, say something recorded in studio and on multiple tracks. But, I have no experience in what recording studios do.

B

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Side bar:

You'd have to hear unamplified music in person. Direct from instrument to your ears.  No mics, wires, cables, mixing boards, tubes or transistors in the path.

I had an opportunity to hear four guys playing banjo, flute, snare drum and harmonica outside in the open.  I use that experience as to what "mechanical" sound should emulate.    I'd say that was about as coherent sound as is possible.  I'd highly recommend this type of experience to anyone. 

 

 

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The point is to preserve the "Art" as best we can whatever was recorded in time and phase.  Much of this is done on headphones which are mostly "Time and Phase Correct) or not, it is the choice of the artist as they will use whatever they like especially voice processors.  We can only preserve what they did as best we can.  RV

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I have no way of knowing but I would assume most jazz could be because they tend to be simple.  I keep saying what goes on at the recording end is the "Art", so it doesn't matter but to reproduce them as accurately as possible does matter to Vandersteen owners.  I believe any recording that sounds like it could have happened your space would need to be very realistically recorded.  RV

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I know that I've told this story before, but I think it applies here.

When my daughter was back in elementary school, she was part of the school band.   Like most school bands of the day, they had a winter concert and a spring concert.  

Being a geeky type of Dad, I thought I'd do something to record these concerts.  So, I purchased a brandy new Sony Walkman Pro (from J&R Music, no less) and a pair of Sonic Studios binaural microphones.  

Long story short, I had about two hours of experience using this rig before the first concert.  My entire sound engineer effort was to make sure the mic gain was about right on the Walkman Pro, sit with my head still, and not cough.  Oh, and change the cassette when it was time to.

I didn't expect much.  If this recording was about the aural equivalent of a home movie, that would be more than good enough.

So, I was quite shocked when I played the output of the Walkman Pro back through the living room sound system, which included Vandersteen 2Ci's.  It sounded as good as the best recording in our entire collection.  That wasn't vanity or ego speaking.  

Huh?

It certainly wasn't due to my expertise (😂) or the great equipment I was using.

What I finally decided was that the recording people had their idea of what the musicians wanted  and what would appeal to the customer base and therefore sell.  That didn't necessarily align with what I thought sounded plausibly real.  But, that's the way it is.

So, I think choosing the records you like and playing them back through the equipment you like is what matters.  Except for the folks who are competing in the marketplace, this isn't a competition. 

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I’m getting a sense there is a fundamental misunderstanding of what “time and phase aligned” really means. Roy Johnson of Green Mountain Audio fame had written a very concise and visually illustrative explanation of all aspects of a “time and phase aligned” speaker design. This was maybe 15 years ago. Since his passing, and subsequent demise of GMA, I can no longer locate it on the interwebs. I’m sure Richard has forgotten more about the subject than I’ll ever know, but here’s an extremely brief summary:

There are 3 fundamental design principles that combine to create a “time and phase aligned” speaker design:

  1. All drivers must be physically aligned to launch a sound wave from the same plane (this is the “time” component of “time and phase aligned”)
  2. Crossovers must sum to simultaneously present a flat frequency response AND no net phase shift of frequencies within the crossover band (this is part a) of the “phase” component of “time and phase aligned”)
  3. All drivers must behave pistonically in the band pass (this is part b) of the “phase” component of “time and phase aligned”)

If you can’t do all 3, you’re not in the running. And while a single-driver speaker passes principle #1 and #2, I’m not aware of any single driver that acts as a perfect piston across the entire audio frequency spectrum.

Now, with amps, “time distortion” is associated with feedback. This is something very different than “time and phase distortion” from a speaker.

There are a couple really good threads on this topic on AudioGon. They are really old…maybe I’ll  see if I can find them.

All that being said, asking about a “time and phase accurate” recording doesn’t really make sense.  It’s also mathematically improbable in a multi-microphone session.  But don’t confuse this reality with something well recorded.

 

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6 hours ago, nrenter said:

All that being said, asking about a “time and phase accurate” recording doesn’t really make sense.  It’s also mathematically improbable in a multi-microphone session.  But don’t confuse this reality with something well recorded.

Each microphone is likely time and phase coherent.

 

This is probably getting a bit off the topic of the recordings being T/P aligned, but it is possibly of interest to the thick glasses types.:

https://www.youtube.com/watch?v=iBPTvMgRBe0

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15 hours ago, Richard Vandersteen said:

I have no way of knowing but I would assume most jazz could be because they tend to be simple.  I keep saying what goes on at the recording end is the "Art", so it doesn't matter but to reproduce them as accurately as possible does matter to Vandersteen owners.  I believe any recording that sounds like it could have happened your space would need to be very realistically recorded.  RV

If I may be so bold as to suggest the following musical example: Bill Evans "Everybody Loves Bill Evans". Play Night and Day and listen particularly to the opening drum solo. You should easily be able to hear the room in which it was recorded and the exquisite detail of the drum. The piano's not bad either. 😋 I attribute this to a beautifully recorded session and of course my time and phase correct Vandersteen speakers.

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nrenter -

#3 is tough to do.  I never heard it included in phase/time discussion, but it makes sense. That disqualifies a lot of speakers. 

I watched the video linked  by BKDad. The wonders of modern science!

What about the ability to pass a square wave?  That's considered the acid test for speakers.  What's your opinion? 

 

 

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7 hours ago, Holmz said:

Each microphone is likely time and phase coherent.

Relative to what? At that point in space? Yes. With respect to each direct / indirect sound wave that hits that transducer? No....that's the "art" captured by the microphone.

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24 minutes ago, DC-93 said:

What about the ability to pass a square wave?  That's considered the acid test for speakers.  What's your opinion? 

Eh...The ideal square wave contains only components of odd-integer harmonic frequencies. Those individuals harmonic frequencies must be time and phase aligned if they're going to sum to a square wave (and since we're dealing with an electro-mechanical transducer, an approximation is the best you'll ever get). The impulse response is the one you want to watch.

Besides, the amp will need to be able to accurately reproduce a square wave before the speaker has a chance to do so, and many amps do a poor job at that. But that's another conversation.

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15 hours ago, nrenter said:

Now, with amps, “time distortion” is associated with feedback. This is something very different than “time and phase distortion” from a speaker.

Is that really true?

A big part of the time distortion question in a loudspeaker is whether the simple harmonics and other spectral content of the program material have the same time relationship coming out of the loudspeakers as are input from the vinyl, tape, or digital source.  

A big part of the feedback situation in an amplifier is that the spectral content is altered by the feedback in an undesirable way, both in the amplitude and time domains.  The harmonics often do not have the same relative phase arrangement, which is just like loudspeaker drivers acting badly when they stop being pistonic.  In fact, some amplifier designers play with this to "voice" their products.  (I also think that the amplifier feedback problem has a lot more aspects associated with it than just the nature of feedback, per se.)

Yeah, amplifiers aren't going to be pistonic (we hope), but it's the same general principle.  The causes may be different, but the results are pretty much the same to me.  But, I may just be arguing semantics, which isn't my intent.

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6 hours ago, DC-93 said:

nrenter -

#3 is tough to do.  I never heard it included in phase/time discussion, but it makes sense. That disqualifies a lot of speakers. 

I watched the video linked  by BKDad. The wonders of modern science!

What about the ability to pass a square wave?  That's considered the acid test for speakers.  What's your opinion? 

 

 

The "Step Response" we show under specifications is a very wide bandwidth square wave.  What is shown is what part of it the speaker reproduced because it is bandwidth limited.  Watch the video on how to interpret them on this site under "Videos".  RV 

 

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5 hours ago, nrenter said:

Relative to what? At that point in space? Yes. With respect to each direct / indirect sound wave that hits that transducer? No....that's the "art" captured by the microphone.

 

Relative to all the tones within the signal itself.
There is no absolute phase, it is relative.

Let’s take the square wave…
If it get projected out of the cabinet as perfect field, except for the mid range getting inverted, then the PSD of it will look largely the same as the with the the mid range not inverted.
But in the time domain, it stops looking like a square wave.

… and the impulse response would also have a “giddy up” in it, and not look like a Dirac delta function.

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