Some speakers slant, some don't. Why?

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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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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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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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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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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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1 hour ago, Jud said:

 

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.

 

I think digital digital crossover may be tuned in system with room correction.

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36 minutes ago, firedog said:

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.

 

Theoretically, active speakers are better way, because amp tuned by drivers, crossover too.

 

It is traditional scheme for studio monitors. That should provide (theoretically again) flat response.

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Waterfal allow estimate signal spectrum in dynamics.

I prefer waterfall plot in 2-D projection (time-frequency-amplitude(brightness)). It allow exactly measure point what you need. 3-D picture look nice for presentations and analyzis of first stage. But it is too complex for detailed analyzis, in my opinion.

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12 hours ago, Ralf11 said:

I'd heard they sound really good, but...

 

Sound perception have no common points for people. Because we can't access to foreign mind.

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Looks like, you have access to my minds, Jud

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Room change the plots of course. But tend (which have lesser "tail") is remains.

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3 hours ago, esldude said:

A 2D variation on the info contained in 3 D waterfall plots. 

 

I like 2-D more for such measurement - more exact for learning.