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Some speakers slant, some don't. Why?


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Floor-standing speaker designs are all over the place. I know the slanty ones are designed so for the purpose of time alignment. One question is, if time alignment is super important, why are there so many designed with flat fronts, apparently ignoring TA?

 

Also, can TA be corrected in the digital domain as part of DSP?

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5 minutes ago, coot said:

Floor-standing speaker designs are all over the place. I know the slanty ones are designed so for the purpose of time alignment. One question is, if time alignment is super important, why are there so many designed with flat fronts, apparently ignoring TA?

 

Also, can TA be corrected in the digital domain as part of DSP?

 

I believe it is done in the crossover when needed. 

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12 hours ago, coot said:

Floor-standing speaker designs are all over the place. I know the slanty ones are designed so for the purpose of time alignment. One question is, if time alignment is super important, why are there so many designed with flat fronts, apparently ignoring TA?

 

Also, can TA be corrected in the digital domain as part of DSP?

Yes, if you want perfect time alignment, DSP is the way to do it. Some add on boxes like DEQX do it, and some actives like the Kii Three or Beolab 90 also do it internally to a digital signal.

 

There are also some speakers like Vandersteen that try to get time alignment right. They do a good job, but the speaker setup itself can't do it as precisely as DSP.

Main listening (small home office):

Main setup: Surge protector +>Isol-8 Mini sub Axis Power Strip/Isolation>QuietPC Low Noise Server>Roon (Audiolense DRC)>Stack Audio Link II>Kii Control>Kii Three (on their own electric circuit) >GIK Room Treatments.

Secondary Path: Server with Audiolense RC>RPi4 or analog>Cayin iDAC6 MKII (tube mode) (XLR)>Kii Three .

Bedroom: SBTouch to Cambridge Soundworks Desktop Setup.
Living Room/Kitchen: Ropieee (RPi3b+ with touchscreen) + Schiit Modi3E to a pair of Morel Hogtalare. 

All absolute statements about audio are false :)

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53 minutes ago, firedog said:

Yes, if you want perfect time alignment, DSP is the way to do it. Some add on boxes like DEQX do it, and some actives like the Kii Three or Beolab 90 also do it internally to a digital signal.

 

There are also some speakers like Vandersteen that try to get time alignment right. They do a good job, but the speaker setup itself can't do it as precisely as DSP.

 

As an owner of Vandersteen speakers, I'm interested: Why can't speaker setup be as precise as DSP?

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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10 minutes ago, Keith_W said:

Jud, it is because time alignment by driver alignment and analog crossover are able to do it within a narrow band only. The actual crossover itself plays havoc with the phase, which introduces delay. There is only so much an analog passive crossover can do before it becomes incredibly complicated and starts introducing losses. After all, if you think about it, an analog passive crossover is lossy enough already. It is powered by ... of all things ... your music signal. 

 

DSP is able to accomplish all this within the digital domain, where the losses are comparitively small. Also, with modern computing power, DSP units (like my setup) are able to achieve time alignment to within 1/1000 of a second. 

 

When I first heard the theory of DSP driven crossovers, I was totally won over by it. The reality is somewhat different (isn't it always!!!). The reality is - doing a DSP driven crossover means that YOU (or ME), as a complete speaker design novice, is tasked with designing what my friend (a speaker manufacturer) calls, "the heart and soul of the speaker". And to do this without training, or if you are like me, only a high school understanding of maths. I have learnt plenty, and I have achieved plenty (my speakers already sound better than they did from the factory), but I have a long way to go. 

 

In short, if the DSP is handled by someone who knows what they are doing, the results can be phenomenal. Ask a twit like me to do it, and the results are ... variable. 

 

Hi Keith (and thanks to coot for starting this very interesting thread).

 

My Vandys are what Vandersteen calls in marketing-speak "phase correct," meaning in normal non-marketing language the crossovers are linear phase, so no monkeying with the phase and no group delay.

 

Also please note that many DSP crossover filters are minimum phase, so these in fact will do what you call "play[ing] havoc with phase" and have group delay themselves.

 

I too have only a high school math (no "s" here in the States :) ) education, so I understand exactly what you are saying about having to try to learn a little bit about a subject where a solid mathematical foundation is necessary for real understanding.  Fun "learning on the job," though, isn't it?

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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26 minutes ago, Jud said:

 

As an owner of Vandersteen speakers, I'm interested: Why can't speaker setup be as precise as DSP?

I think you know the answer to this.

With well done DSP, you can basically take all the factors into account (including the slight alignment problems caused by the analog/mechanical attempt at time alignment within the speaker itself); so, as Keith said, you can get virtually perfectly aligned results. 

With analog you will get, by definition, less precise results. Doesn't mean it isn't good. The OP asked if time alignment could be done in DSP.

Of course, in both scenarios you also have to place your speakers precisely to preserve the correct time alignment. 

Main listening (small home office):

Main setup: Surge protector +>Isol-8 Mini sub Axis Power Strip/Isolation>QuietPC Low Noise Server>Roon (Audiolense DRC)>Stack Audio Link II>Kii Control>Kii Three (on their own electric circuit) >GIK Room Treatments.

Secondary Path: Server with Audiolense RC>RPi4 or analog>Cayin iDAC6 MKII (tube mode) (XLR)>Kii Three .

Bedroom: SBTouch to Cambridge Soundworks Desktop Setup.
Living Room/Kitchen: Ropieee (RPi3b+ with touchscreen) + Schiit Modi3E to a pair of Morel Hogtalare. 

All absolute statements about audio are false :)

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Just now, firedog said:

I think you know the answer to this.

With well done DSP, you can basically take all the factors into account (including the slight alignment problems caused by the analog/mechanical attempt at time alignment within the speaker itself); so, as Keith said, you can get virtually perfectly aligned results. 

With analog you will get, by definition, less precise results. Doesn't mean it isn't good. The OP asked if time alignment could be done in DSP.

Of course, in both scenarios you also have to place your speakers precisely to preserve the correct time alignment. 

 

Yes, I did think that was what you were going to say. :)

 

I would say DSP might be more *flexible* than driver placement, but I don't know necessarily about more *precise*.  Using the instructions in the Vandersteen manual, I've got speaker placement down to about 1/8" in all dimensions.  Sound takes about .000009 second to move that far.  I haven't tried DSP crossovers - would you notice a difference of that amount in their timing? 

 

Of course I move my head more than 1/8" when listening to music, but then I would with DSP crossovers as well.  As you said, effectiveness of both DSP and driver placement will depend on the physical relationship between drivers and listener's ears; as soon as you move your head, there's a little less precision.  

 

Where I can see DSP working better is for situations you cannot solve by changing room characteristics and speaker placement in your particular listening space.  But you will want to watch out for things like the phase effects Keith and I mentioned.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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14 minutes ago, Jud said:

 

I would say DSP might be more *flexible* than driver placement, but I don't know necessarily about more *precise*.

 

Hi Jud.

 

If you mean time delay precision, DSP have no limit by time shift size. It is more precise than sampling period T=1/[sample rate] and not only multiply T.

It is so, because digital signal, restored to analog, is not "stairs" of voltage. But it is curve interpolated by analog filter. Therefore time delay may be T, 2*T, T/2, T/9, T/1.4, T*2.1 etc.

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4 minutes ago, audiventory said:

 

Hi Jud.

 

If you mean time delay precision, DSP have no limit by time shift size. It is more precise than sampling period T=1/[sample rate] and not only multiply T.

It is so, because digital signal, restored to analog, is not "stairs" of voltage. But it is curve interpolated by analog filter. Therefore time delay may be T, 2*T, T/2, T/9, T/1.4, T*2.1 etc.

 

Hi Yuri.  Yes, completely agreed.  But when you implement the digital crossover in a physical space with speakers and a listener, then the limitation is how precisely you can locate the speaker drivers and the listener's ears with respect to each other, just as it is with analog (physical) crossovers.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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3 minutes ago, Jud said:

 

Hi Yuri.  Yes, completely agreed.  But when you implement the digital crossover in a physical space with speakers and a listener, then the limitation is how precisely you can locate the speaker drivers and the listener's ears with respect to each other, just as it is with analog (physical) crossovers.

 

I re-read posts above, but I can't understand what difference between digital and analog crossovers relatively speakers. Both can provide delay.

Analog crossover can shift phase signal (time delay) in small range and depend on frequency, I suppose. It is hardly managed.

Digital crossover have wider range of delay value and almost infinite low step of altering of delay.

Digital crossover can model almost any analog one.

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To put this question of timing and precision in a physical space another way:

 

Let's think about the 1/8" = .000009 second I mentioned before.  For convenience, we'll refer to this as 9 microseconds.  The highest frequency of the audible range usually quoted for humans is 20kHz.  One wavelength occurs in 50 microseconds.  Reasonably settled research results have shown humans can distinguish interaural time differences on the order of 10 microseconds, so we're getting close to that 1/8" distance.  (Kunchur got a result of 5.6 microseconds, but as with many things related to audio, his research has come in for a fair bit of criticism, so let's go with the greater bulk of results in our discussion.)

 

Figuring that we don't need to quibble about a microsecond among friends :) , let's say we'll notice if distances between speaker drivers and listener's ears are off by more than 1/8".  Thus if we position our speakers with a precision of 1/8", we need to hold our heads absolutely stock still.  On the other hand, if you want to say we can use instruments to measure arrival times at the listening position with arbitrary sub-microsecond precision, then that gives us an entire 1/8" of freedom to move our heads during our music session.  Happy listening! :D 

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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11 minutes ago, audiventory said:

 

I re-read posts above, but I can't understand what difference between digital and analog crossovers relatively speakers. Both can provide delay.

Analog crossover can shift phase signal (time delay) in small range and depend on frequency, I suppose. It is hardly managed.

Digital crossover have wider range of delay value and almost infinite low step of altering of delay.

Digital crossover can model almost any analog one.

 

Hi Yuri -

 

This interview with Richard Vandersteen discusses his use of first order crossovers to avoid phase effects and group delay (it has a bunch of the usual marketing stuff, too, which of course you can ignore): http://www.soundstage.com/interviews/int07.htm

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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44 minutes ago, Jud said:

 

Hi Yuri -

 

This interview with Richard Vandersteen discusses his use of first order crossovers to avoid phase effects and group delay (it has a bunch of the usual marketing stuff, too, which of course you can ignore): http://www.soundstage.com/interviews/int07.htm

 

Thank you for link, Jud.

 

I don't developed acoustical systems and have minimal knowledges in wave theory.

 

At my look, simplest way use flat positions of speakers. Like it done in sound projectors.

 

From mathematical point of view it allow calculate phase (time) delay for each frequency range for desired interferention in ear point without accounting "internal diffractions or reflections" (if I correctly understand what is mean).

 

Digital crossover can emulate any analog one (1st or other order). It is easier in adjusting.

 

When I read the article, I got: when we tune multiband speaker, our aim - all bands must work as one band.

 

Order of filter is technological matter only. It is not matter as itself. Important summary response of several filters accounting driver's features.

 

During design time, we must model crossovers and drivers as united system. In implementation time we must apply digital crossover to speaker with filters that was calculated during design. Of course, we will correct filters by practical measurements.

 

 

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9 minutes ago, audiventory said:

From mathematical point of view it allow calculate phase (time) delay for each frequency range for desired interferention in ear point without accounting "internal diffractions or reflections" (if I correctly understand what is mean).

 

Hi Yuri.  This is marketing.  At that time Vandersteen did not house its tweeters or midrange drivers inside boxes, and did not mount them on "baffles" (horizontal surfaces of considerably larger dimension than the drivers).  See the image below:

 

 

Vandersteen 3A.png

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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1 hour ago, Jud said:

 

Hi Yuri.  This is marketing.  At that time Vandersteen did not house its tweeters or midrange drivers inside boxes, and did not mount them on "baffles" (horizontal surfaces of considerably larger dimension than the drivers).  See the image below:

 

Hi Jud.

Looks like he use soft walls for avoiding reflections. Wave interference is too complex thing. I don't ready say something about it. Need model such system for learning theoretical abilities, first. Interestingly, how they design systems? They are use modeling software?

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Wow. You guys are way over my head with your tech-talk - (maybe I should listen from above my head?).

So I guess if I'm looking to buy I should look for speakers that are either slanty or have digital crossovers and some mention of digital time-delay correction?

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4 minutes ago, coot said:

Wow. You guys are way over my head with your tech-talk - (maybe I should listen from above my head?).

So I guess if I'm looking to buy I should look for speakers that are either slanty or have digital crossovers and some mention of digital time-delay correction?

 

Or digital crossovers.

 

Not the worst idea in the world. :)

 

What would your notional budget be?

 

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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15 minutes ago, coot said:

So I guess if I'm looking to buy I should look for speakers that are either slanty or have digital crossovers and some mention of digital time-delay correction?

 

7 minutes ago, Jud said:

Or digital crossovers.

 

Of course, all depend on implementation. As usual :)

 

By my experience of tuning sub by ears, it is non-trivial task.

 

Jud, are there digital crossovers with auto tuning by microphone?

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21 minutes ago, audiventory said:

 

 

Of course, all depend on implementation. As usual :)

 

By my experience of tuning sub by ears, it is non-trivial task.

 

Jud, are there digital crossovers with auto tuning by microphone?

 

Yes, no way I'd try this by ear.  You should ask Keith, I think, because I have no experience using digital crossovers.  I'm sure you can *tune* digital crossovers using mics, but I don't know if there are crossovers that auto tune by microphone (I understand this to mean the crossover would tune itself using a connected mic).

 

I also wonder (Keith?) whether the tuning that one can do oneself extends not only to frequency but to measurements of group delay and phase.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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25 minutes ago, coot said:

$30 max; like you say, "notional"!

Specifically, Legacy Aeris

 

They sure look nice. :)

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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59 minutes ago, audiventory said:

 

Hi Jud.

Looks like he use soft walls for avoiding reflections. Wave interference is too complex thing. I don't ready say something about it. Need model such system for learning theoretical abilities, first. Interestingly, how they design systems? They are use modeling software?

 

Hi Yuri.  Yes, I don't think there are internal reflections, but that is likely true of most speakers.  I don't know how they do their designs, but I would imagine they must use software.  

 

Richard Vandersteen likes to project a certain image (former truck driver over 2 meters tall; credits his wife with inventing the "baffle-less" design when she played music through speaker drivers lying on a table not installed in a box; and you read in the interview the stuff about dragging shovels around to design the crossovers), but if I remember correctly, Vandersteen was one of the very first speaker companies to use Fast Fourier Transform analysis.  And I can tell you everything I can feel under the cloth that wraps my speakers is absolutely rigid.  It takes some good work to create a design that can be built relatively cheaply and have such rigidity.

One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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I just  remembered that the KEFLS50  actives have, in addition to UniQ alignment of drivers, has an option for additional  DSP time alignment, in order to improve the time alignment.

Main listening (small home office):

Main setup: Surge protector +>Isol-8 Mini sub Axis Power Strip/Isolation>QuietPC Low Noise Server>Roon (Audiolense DRC)>Stack Audio Link II>Kii Control>Kii Three (on their own electric circuit) >GIK Room Treatments.

Secondary Path: Server with Audiolense RC>RPi4 or analog>Cayin iDAC6 MKII (tube mode) (XLR)>Kii Three .

Bedroom: SBTouch to Cambridge Soundworks Desktop Setup.
Living Room/Kitchen: Ropieee (RPi3b+ with touchscreen) + Schiit Modi3E to a pair of Morel Hogtalare. 

All absolute statements about audio are false :)

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