Do you know the designers or the design process? Have you heard the speaker?
I do, I have.
Hi,
I'm leaving this thread, seems some of you can't work out purely axial
alignment doesn't account for differences in the acoustic centres re
time alignment (not that it matters much) and cannot respect an
informed opinion on something that is clearly about marketing.
Nothing against Focal, I can see the wood for the trees.
rgds, sreten.
As ever, those with the extreme views think they know something.
I'm leaving this thread, seems some of you can't work out purely axial
alignment doesn't account for differences in the acoustic centres re
time alignment (not that it matters much) and cannot respect an
informed opinion on something that is clearly about marketing.
Nothing against Focal, I can see the wood for the trees.
rgds, sreten.
As ever, those with the extreme views think they know something.
Last edited:
It's not purely axial, because the rotation is around the point below the tweeter, not the tweeter acoustic center. The acoustic center is moved slightly forward, slightly down, and there is an axial rotation.
edit: I guess that was kind of an upside-down description since it's actually the woofer baffle that is tilted relative to the listener - same deal though.
edit: I guess that was kind of an upside-down description since it's actually the woofer baffle that is tilted relative to the listener - same deal though.
Last edited:
Those with direct knowledge of, and experience with, a thing do not hold extreme views. Perhaps they know more than the armchair generals.
Perhaps....
Hi. Yes, it's also sonic.
The change in axial response due to cross-over phase is trivial and common knowledge. I may have first simulated the effect with punch cards.
Last edited:
the last six posts in this thread have been deleted due to being personal. By all means debate, but debate the ideas, keep the personal stuff out of it. 
Yes, that was a HORRIBLE episode, wintermute! Glad you're on top of it. 
Let's reiterate why time-alignment is a GOOD THING. Just give me ten uninterrupted minutes to finish three easily-digested posts here, which will reinvigorate this topic I hope.
First a nice conventional crossover on 6" bass and fabric 1" tweeter. This sort of regular speaker roughly speaking. Good phase and frequency response and a lack of cone breakup thanks to a cunning notch on the woofer.
Let's reiterate why time-alignment is a GOOD THING. Just give me ten uninterrupted minutes to finish three easily-digested posts here, which will reinvigorate this topic I hope.
First a nice conventional crossover on 6" bass and fabric 1" tweeter. This sort of regular speaker roughly speaking. Good phase and frequency response and a lack of cone breakup thanks to a cunning notch on the woofer.
An externally hosted image should be here but it was not working when we last tested it.
Attachments
Now let's do something unexpected and neat and turn the speaker upside down. You also need to do something else. Which is wire the tweeter out of phase...
Here's the neat thing, because the crossover point is about 3kHz, you need to listen at a point above axis which effectively sets the tweeter back about 5cm, which corresponds to half a wavelength. You then get an interesting resolution of detail which sounds nice. This is simple time-alignment and you can try this at home.
Below is the new frequency response and phase. Quite acceptable, even if I like more tracking of phase.
An externally hosted image should be here but it was not working when we last tested it.
Here's the neat thing, because the crossover point is about 3kHz, you need to listen at a point above axis which effectively sets the tweeter back about 5cm, which corresponds to half a wavelength. You then get an interesting resolution of detail which sounds nice. This is simple time-alignment and you can try this at home.
Below is the new frequency response and phase. Quite acceptable, even if I like more tracking of phase.
Attachments
Now let's go the whole hog and design a speaker roughly like Joachim Gerhard's excellent Sonics Anima time-aligned speaker. I'll do this with a simpler filter and paper woofer and softdome tweeter.
Below is a much simpler circuit which really works best with well-behaved drivers like plastic polycones. It's roughly 4th order acoustic. Phase tracking is good. Time alignment is good. Frequency response good too. You could even try first order filters, which actually end up between 2nd or 3rd order acoustic. My only criticism is the higher woofer cone-breakup showing its face, hence I suggest a polycone is best for this sort of simple filter. It's your choice. But there IS something in it.
The last image is lobing. You can see there is a sweet spot above axis.
An externally hosted image should be here but it was not working when we last tested it.
Below is a much simpler circuit which really works best with well-behaved drivers like plastic polycones. It's roughly 4th order acoustic. Phase tracking is good. Time alignment is good. Frequency response good too. You could even try first order filters, which actually end up between 2nd or 3rd order acoustic. My only criticism is the higher woofer cone-breakup showing its face, hence I suggest a polycone is best for this sort of simple filter. It's your choice. But there IS something in it.
The last image is lobing. You can see there is a sweet spot above axis.
Attachments
Why?
Did someone say it wasn't a good thing? The question was what's up with Focal's wacky baffle, and time-alignment does not really answer that. Personally, I think that "to be consistent with the larger speakers in the lineup" is a satisfactory reason.
Just thinking out loud here, but to me it would appear that this solution (slanted baffle but non-slanted tweeter) is done to correct for the downward tilt in the vertical lobe that typically results from non time alignment with an TM configuration.
Slanting the mid woofer up, and also the fact that the tweeter will be somewhat further back due to the top of the cabinet being further back than the bottom, would seem to offer a two pronged approach to the problem. The tweeter is not necessarily back far enough to be considered to have the same accoustic centre as the woofer, but by angling the woofer as well, the direct on axis sound from the woofer will hopefully sum with the on axis arrival from the tweeter at the same spot. This would be pretty listening distance specific though I would think.
Note I have not done any mathematical analysis of this, just tossing in an idea.
Tony.
Slanting the mid woofer up, and also the fact that the tweeter will be somewhat further back due to the top of the cabinet being further back than the bottom, would seem to offer a two pronged approach to the problem. The tweeter is not necessarily back far enough to be considered to have the same accoustic centre as the woofer, but by angling the woofer as well, the direct on axis sound from the woofer will hopefully sum with the on axis arrival from the tweeter at the same spot. This would be pretty listening distance specific though I would think.
Note I have not done any mathematical analysis of this, just tossing in an idea.
Tony.
Steve I have a pair of those MS cuties, cost me 3 bucks at the thrift store, maybe since the terminals are banana plug only. I don't recall that much going on in the x/o though. This reminds me of "outcome based" as an ideal, being married to a (thankfully retired) teacher. My question is, a lot of these chats about electrical + acoustic crossover slope assume a smooth rolloff above a freq defined by cone dimension and vc inductance. What usually happens is a peak in the upper middle of this friendly fantasy that results in a muted screech that I hear in almost all two ways that haven't been heavily modded, pooged, tweaked, you get my drift.
In the case of Focal, not likely. I've not heard this particular speaker, but older generations of Utopia models had pretty glaring flaws.
The answers to the OP are "cosmetic" and in the case of the woofer recess "to allow a partial grill" and "maybe to look a little bit like the much better TAD speakers."
Pano,
I don't know about the newer Be Focal dome tweeters but the earlier versions are some of the worst sounding domes around. Terrible titanium noise and resonance up high. Extremely fatiguing sound from those older models. Yes I have some still sitting on a shelf that I have tested. Not a fan of inverting a dome either, just marketing hype, nothing like creating a resonant chamber in front of the dome. But they do have nice build quality, I will give them that.
I don't know about the newer Be Focal dome tweeters but the earlier versions are some of the worst sounding domes around. Terrible titanium noise and resonance up high. Extremely fatiguing sound from those older models. Yes I have some still sitting on a shelf that I have tested. Not a fan of inverting a dome either, just marketing hype, nothing like creating a resonant chamber in front of the dome. But they do have nice build quality, I will give them that.
I;ve always had the opposite feeling, not a big fan of most typical domes, but the inverted domes i'be liked have been paper. Like many things execution is probably more important.
dave
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.