Sloped baffle

The DIY forums and this one have something in common. Very rarely does anybody listen to any advice or criticism that they don't want to hear.

Lewinski... great post. I was impressed by the various digital analyses and corrections that the software was able to effect. Hopefully, speaker manufacturers will be able to achieve greater time and phase alignment, driver linearity and low distortion by designing better X-overs. It may be that the best solution will be an active crossover that can effect the various functionalities that were the subject of your post.
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After all, not everybody is a former NASA rocket scientist or a Steven Jobs/Bill Gates computer genius.

Thanks Bifwynne.

Not sure if you were implying I'm a computer genius. But to clarify it just in case: I'm certainly not!!! Not even very savvy, honestly! It looks a lot harder than what it is. I just have a dedicated server with JRiver and the Audiophile Optimizer running in it. The hardware is optimized. Amazing sound. And it was a set it and forget it setup.

Cheers!

what is your definition of "premium drivers"? Cost of the driver? Cost of a commercial speaker using this driver? The marketing hype surrounding that driver that makes you believe it must be the best?
From the little I know, some Scanspeak drivers are very good performance that would qualify for time-coherence.
Accuton drivers need not apply for time-coherence.
I don't know much about Raal.
Be careful how you choose your drivers - don't let cost be the judge - look at their freq bandwidth & where you intend to cross them over.

Bombaywalla,

Very fair point. Honestly, I have not done much research on drivers yet. I was trying to provide examples to show what I meant and used the brands that are usually mentioned in reviews as premium. I did look into their prices, and in a way I was think along the lines of price. What would be premium brands sound-wise?

BTW, I never thought about drivers not being time-coherent. What does that mean? I thought time misalignment was between/among drivers.

I have not even started looking into building a speaker. I am now thinking through / coming to terms with moving away from a nice digital and analog chain (Audiophilleo with PurePower going into a Metrum Octave, going into a Lamm LL2) and into a multichannel DAC driving multiple amps directly and using software for volume control. I'm sure many can relate to having second, third, and forth thoughts on such a move.

The benefit of driver time and phase alignment seems to be significant. The benefit of multiamping I believe is well documented, but the challenge is on the implementation. Digital room correction also makes sense to me.

After taking this plunge next step will be thinking which amps to get to drive my existing speakers. And later I will look into building my DIY speakers. Nevertheless I wanted to chime in here to provide a different approach for achieving time alignment.

BTW, yes, in a way this is similar to the Meridian path. But I do like tubes!!! So my idea is a SS or class D amp for woofers and tubes for midrange and tweeters. And I also have two power subs. But you made me remember about Meridian's approach. I will look into it. I believe they deliver a digital signal to the speaker and then convert it to analog inside the amp. I'll check if they have processors that deliver multiple analog channels, but I'm also wary of spending big on digital components considering it is not yet mature and hence evolving so fast.

As I said before, great thread!

BTW, I never thought about drivers not being time-coherent. What does that mean? I thought time misalignment was between/among drivers.

Let's look at just 2 of the physical components of a driver (imagine a midrange driver): the cone and the suspension (the surround and the spider).

The cone itself has mass, and because of the kinetic energy of a cone moving outward, it sometimes just can't reverse direction as quickly as the signal is asking. Sure it responds, but with a very slight delay. This delay is one source of phase distortion.

The suspension not only centers the coil in the gap, but defines the resting position of the coil within the gap. Don't believe me? Gently push in on a mid-woofer, and let go. The speaker pushes back out to the resting position as defined by the suspension.

Now, small movements around the "resting point" all experience the same (minute) amount of resistance from the suspension. This is by design and is where the driver operates with minimal effective phase distortion.

Now, midrange drivers require larger strokes to produce lower frequencies, and the suspension applies more (nonlinear) resistance against the movement of the driver as the driver approaches X-max, imparting another set of phase distortions.

This is an oversimplification of the subject. But shows that (good) time-and-phase aligned speakers require more than just a sloped baffle and first-order crossovers.

Lewinskih01
....What would be premium brands sound-wise?....

Well not sure how many of these brands are still accessible to the public but.....Scanspeak makes some very good drivers, another excellent brand for woofers is Audax & Peerless, yet another brand for mids & tweeters is Morel & Eton. I'm sure that there are many others.

BTW, I never thought about drivers not being time-coherent..... I thought time misalignment was between/among drivers.

yes, you are right - drivers in & of themselves are not time-coherent. Drivers are linear (wide frequency range of operation) well above the frequency at which you cross them over. Using such drivers greatly helps to manuf time-coherent speakers because the driver itself does not come into play, it's just the electrical x-over (or in your case the electronic x-over since you will be using DSP).
yes, you are correct - time misalignment is between/among drivers.

But you made me remember about Meridian's approach. I will look into it. I believe they deliver a digital signal to the speaker and then convert it to analog inside the amp. I'll check if they have processors that deliver multiple analog channels,

:-) that's the point of these forums. Yes, you are correct - they do deliver a digital signal to their speaker & convert it to analog inside the speaker box. Pretty complicated stuff w.r.t. all the signal processing they do. How long has Meridian in business? I would say some 40 years. How many people own & appreciate Meridian speakers? I personally don't know any. Doesn't mean that there aren't any/many. Also check into Emerald Physics' methodology.
Just a thing to be aware that you are putting all your trust into that DSP software & the handles it gives you to vary x-overs & slopes, etc. I hope that you like the exact flexibility that is given to you & that you are not saying "I wish this software had this other XYZ flexibility".
The DSP signal processing is touching your music signal in a very fundamental way in that the entire music signal has to go thru the DSP before you can hear it. Same deal with the passive x-over. But the difference is that you change the quality of the cap or the inductor or the hook-up wire & you can change the sound to your liking. It appears that it's not that simple with the DSP software - you cant go in there & change the code. Or, maybe I'm not thinking of this correctly?
So, if I'm envisioning this correctly - computer digital out runs into the DSP software which breaks the audio signal into highs, mids, bass. You get 3 digital streams now. You feed these 3 streams into 3 identical DACs or 1 Pro quality DAC able to output 3 analog streams (one box would be better as everything sits in 1 chassis & has a better chance of being matched to the other analog stream). Then 3 analog streams into 3 power amps - you need to match these very well too: same input sensitivity, same gain, same sort of clipping algorithm, same dynamic headroom extension, same power output capability, same current source/sink capability.
There are a lot of variables to contend with. That's why I wrote earlier that it's a huge undertaking. You'll have to become very savvy with DSP (which is discrete-time) & analog signal processing (which is continuous-time).
There aren't many people who make speakers using this technique - Meridian, Linkwitz DIY, Emerald Physics that I can think of. maybe this is the wave of the future???