Ever hear a group of unamplified musicians playing spread apart on a stage...anywhere? No phase or time allignment occurs. Hmmm...
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the powered KEF 50 use DSP to correct the passive KEF 50 impulse response...somebody at KEF thought that a worthwhile thing to invest effort into....hmmmmmmmmm....
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Using vandersteen speakers. They are a pain in placement. But when you got it right the time aligent/phase coherent design is gorgeous. About 5 years go i measured/corrected them (for most my horrible Room acoustics) with Mathaudio Room EQ (incombination with Foobar 2000 for free) sound wise, it Raised them to another higher level esspecialy in imaging which they already did well. In 45 years time investing in a measuring mic of less than 100,- euro is the best audio investment i did in 45 years time.
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I'm sure I'm biased because I have Thiel CS 3.5's, but, even though they are voiced differently, I find that Thiels and Vandersteens (and Maggies) just sound right compared to so many otherwise good speakers. I'm not sure, but I believe the phase and time coherence make a big difference, at least to me!
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If I have to pick the most important factor in sounding live it's linearity. Double the input then the output should double. Triple and etc. And it's true in the entire system, not just speakers. I recall Bud Fried's speakers were linear phase and roughly time aligned but it was their linear changes in sound pressure level that made the sound real. And There are non linear phase and non time aligned speakers that sound real like ATCs and again it's linearity that makes it happen.
Why stop there? (one should be able to rank them maybe using Floyd's book)
But I think I agree with you, as non linear systems have a lot of harmonic distortion and IMD.
We can talk about the frequency response as the thing the translates best statistically to "being perceived as being good".
So if one had a speaker that was not time/phase correct, but had good frequency response, no cabinet resonances, and a good pattern, then they would sound better than a time/phase aligned speaker with bad FR.
If one uses a DSP to make the FR good, then we get a different fight.
If one uses a different DSP to also do impulse response (phase) EQ, then it is different again.
However a DSP cannot remove cabinet resonances , harmonic distortion, IMD, and port noise, and compression.
If you got ^those^ good however, one could do the rest in the specific few DSPs that allow it.
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If I have to pick the most important factor in sounding live it's linearity. Double the input then the output should double. Triple and etc. And it's true in the entire system, not just speakers. I recall Bud Fried's speakers were linear phase and roughly time aligned but it was their linear changes in sound pressure level that made the sound real. And There are non linear phase and non time aligned speakers that sound real like ATCs and again it's linearity that makes it happen.
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Using DSP a linear phase perfect impulse response can be done and is in certain active speakers.
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It can but speaker designers who use computer models are getting very close. That being said and owning Vandersteen 5As, just because these speakers are does not mean that they always sound fantastic. There is more to making a system sound fantastic then the speaker.
Happy Listening.
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Professional speaker management systems at the top of the scale in performance all have adjustments for time alignment. When you start talking about several stacks of drivers it starts getting a bit more complicated. There is a masters level course in the subject at one ot the TX universities, professor wrote a text on the subject. I got the books somewhere can not remember the professors name.
If you setup a speaker system in a anechoic chamber you can definitely hear the change with changes in timing if you are sensitive to the issue. The crossover points seem to be noticed by most people even in the a good listening room. To me it just sounds noisy at the crossover points.
I am working out a design for amps and such a management system on a budget. If interested check out "mini DSP", they have off the shelf solutions that are not too expensive. The DSP chips they use would be a good place to start a study of the issue, easy to work with.
I like the idea that the system could be used to make a system with a series of appropriately placed divers and apply a spread spectrum digitization of someone talking and aim the system at particular person in a crowd and that person would be the only person that would hear the person talking everyone else will only hear noise. Nice toy for spies. There is a patent on such a system.
So yes, it makes a difference.
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I only noticed time alignment issues with present highly modded Klipschorns when in stock form. Originally mid driver and tweeter mounted on same baffle, mid driver sat probably 17" behind tweeter, this due to long exponential horn on mids. My mods replaced stock horn with Volti tractrix and tweeter mounted on separate baffle. I've mounted tweeter baffle essentially in line with mid driver. In stock form Klipschorns and some other Klipsch perceived as bright, certainly true with mine in stock form. Better time alignment has meant better tonal balance, no more of that beaming high and mid high freq., also far superior imaging, sound staging. But then, this was extreme example of poor time alignment.
My Merlin VSM-MM never had perceptual time alignment issues. Having said that, I did run Omega single drivers with 2a3 at one time, coherence was really something special, even compared to Merlins, a two way which have rep as being very coherent.
As for phase, I recall seeing a website some years ago where someone measured and listed cd's recorded in proper and reversed phase, turned out recordings pretty random here, reason for phase switches on many dacs.
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All the rage back in the early 80s. Until everyone discovered that it was marketing nonsense.
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Jason excellent point which is why i don't use or advocate modern multi track recordings as a reference. Cat will chase own tail using those......
2 or 3 microphones please....
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I'm afraid that while much is made of it
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Yep, |
, matching of drivers to within .25 db
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All my drivers are completely dif sensitivity.
87, 91, 95 and about to add a 93.
Sounds wonderful.
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This is what some DIYers are saying might affect my new dual FR design speakers,, that running a pair of FR, one FR might be slightly nearer my listening field and thus reaches my ear BEFORE the other FR,, this a bunch of muddled fq's.
I say not so.
I've experiemented with this Duo design and had no issues with time/p incoherency.
Its all a myth.
Sure if you have 1 driver 1 foot behind the other,, the its possible, but all drivers at same distance, there is no such thing as 1 driver faster than the other due to one milli second slower/faster vs the other driver.... thus distortion,, its all baloney.
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Eric - yes and as you no doubt aware, there are lots of other fundamental design principles at work; pistonic drivers, matching of drivers to within .25 db, testing the assembly in aneochic chamber against the reference, cabinet within a cabinat, high pass filtered midbass and up, same transfer function for main amp as sub amp, 11 bands of EQ below 120 hz for best image placement vs eliminate bass issues and live w image....the list goes on, since 1977
Not for everyone
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Certainly it makes for better sound staging and imaging.
...however, there are varying degrees of what the industry describes, for example, as "time alignment" out there. It can sometimes strike me as more of just a marketing thing...as though either the makers think that at least half the buyers don't really understand what a proper time alignment can attain...or that half the makers don't understand it...or both maybe, IDK.
Everybody has their own way of making and selling speakers, or choosing them FTM. But IME when you technically do this topic justice, you do get some pretty good rewards.
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Listen for yourself.
I'm afraid that while much is made of it, I've heard time aligned and non time aligned systems and... MEH!
For me it's not the convincing superioiur sound experience the vendor's claim, and acousticians I trust say the same.
That's not to say there are not some very excellent time aligned speakers. The top of the line Vandersteen come to mind.
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Angeling the speakers back reduces 1st reflection problems, ....it isn't time aligned
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One of dozens of variables that can be used to build good speaker... undoubtedly doing this has a negative effect on something else. Audio design is all about trade offs.
Well said. I think with the improvement in driver technology and materials the compromises of 1st-order crossovers has been largely mitigated, but there are always trade-offs. I had Thiel CS1.6es in my system for a while, and I do think there is a certain “rightness” about a well-implemented time/phase coherent design, but that said I hear a lot of the same properties from the likes of Joseph Audio so pick your flavor. All else being equal, which is NEVER the case, I’d take time and phase coherency, but only IF the rest of the sound profile meets with my overall tastes.
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One of dozens of variables that can be used to build good speaker... undoubtedly doing this has a negative effect on something else. Audio design is all about trade offs.
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Angling back the front baffle of the enclosure usually isn't enough, in and of itself, to achieve the desired results.
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Almost twelve years ago when I purchased my current set of speakers even my family could hear the difference.
"Rightness." Why not? I don’t know what to call it in audio speak. After years on the audio merry-go-round the first word out of my mouth was BINGO! It had taken me years to simply understand what was missing.
Laughingly unexpected is how quickly and easy it is to hear designs that are lacking.
Your KING OF SUBWOOFER thread sure got ’em bouncing off the walls. I'm not seeing it, did it get pulled?
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Time Aligned, My personal Experience: YES. Size of listening space and distance effect the importance.
Absolute Phase, makes sense that it does, I just have not paid attention to Absolute Phase personally. I suspect if I did, absolute phase will produce increased distinctness. Slightly out of phase is a technique engineers use when mixing to diffuse, widen .......
Distinctness (not brightness) is very important, it more accurately reveals what the artists and engineers released. It is the primary improvement achieved by my newly acquired CD Player
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Time-Aligned Signal PRIOR to amplification: then Maintain that with time Aligned Speakers
My conclusion while searching for a CD Player with a preferred sound(not everyone's preferred is better) is:
DAC = Salad. Combo of stable dots, then Dual Time Aligned DAC's, then the addittives of sampling, anti-jitter, re-clock, proprietary filters ... can yeild a perceptible difference, for me it is 'distinctness'
which starts out as a small difference, but when applied to everything happening, the drummer's brush work, primary singer, primary instruments, back-up singer(s), improved awareness of an instrument, imaging, each piano note. Repeat, not brightness, not glass precision, but a slight veil removed to hear the distinctness the artists and engineers intended.
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My Time Aligned Speakers
AR2x, my first 'decent' speakers when 18 years old, ollege days, listening to the Nightbird (Alison Steele) and Cousin Brucie late nearly every night,AR2x, sounded better when slanted slightly.
JSE Infinite Slope Model 2's, Time Aligned Sloped Front, and the patented infinite slope crossover, are the most accurate speakers I own. My son has them now.
My Current Speakers, 15" woofers, horn mid and horn tweeters: preferred sound, (less measured frequency distribution accuracy than the JSE's), sound better after I added a 1-1/2" block within the base to raise the front/tilt them back to:
1. achieve time alignment (not measured), simply approximately achieved based on observations of the angle of other time aligned speakers I have seen and heard.
2. aim tweeters 'up' to direct received sound to seated ear height
3. change the angle of reflections of the larger drivers off the floor/ceiling, as well as toe-in alters the side wall reflections. I recently refined my toe-in with a sound meter, a small change yeilded
IOW, sloped fronts for Time Alignment improvements are multiple.
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Not being time and phase correct does not eliminate a speaker for me. A time and phase correct speaker has a "rightness", for lack of a better term, that a speaker that is not time and phase correct does not have IME. The negative that I have seen with them is that many of them will suffer dynamic compression when pushed hard. It is a trade off and depends on listening habits and what one truly values. As stated above, some either don't hear it or don't place that much value in that particular trait. To each their own.
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Absolute phase gets thrown out the window with multi-track pop/rock recordings.
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there is a big difference between absolute phase and time and phase correct, but IF you can't hear absolute, move right along....
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some people are essentially deaf to it. Move on if it doesn't float your boat. My favorite Strad player " gets it ". So do I.
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One on a very long list of things that make a better loudspeaker. The ones I have now are light years better than the previous ones, even though they were beautifully and conspicuously time-aligned and the better ones equally obviously are not.
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If one defines fidelity as when the output of the acoustical waveform matches what the signal is... Then it seems like it cannot happen to be correct until the time and phase response is correct. All things being equal, it will will not hurt.
A lot of people believe that we hear in the frequency domain. It is certainly easier to describe a system’ s frequency response in the frequency domain.
it is also also easy to describe a "system response" using the transcient response.
But a lot of scientific work suggests that in reflective spaces, Phase is not the primary issue.
Maybe swap your red and black wire on both the left and right speakers and test whether it sounds any different when the signal is reversed in phase... (some people easily hear it and some people do not.)
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