Concentric Cone-Yay or Nay?

[GT]

alfalfa,

I think at this point, we are going to have to agree to disagree.

One more log for the fire!

Music is full range, and should be reproduced in the same manner.

I know most don't agree with me on this subject, but I feel strongly enough about it, that I have to preach.

I have an open mind, and gave the woofer tweeter speaker more than enough of a chance to proove itself, also spent a lot of bucks. I was never satisfied with the sound.

I finally concluded that the inherent problems, can not be overcome.

I finally have a speaker that I am satisfied with, after all these years, that's why I'm sharing my thoughts.

This is not a debate that I expected to win, doesn't matter, just had to share!!

GT

 

[alfalfa]

Thats cool GT. It is an interesting topic - definitely not a debate to be 'won' or 'lost'. It is good to hear some alternative thoughts in this forum. I have trouble finding anyone here that thinks phase coherency is a good thing or important. Catch you later.

 

[GT]

Can't believe I'm debating with one of the Little Rascals.

What's next, arguing with Buckwheat about piezo electric chirp?

Spanky in the mic forum, saying the C1 is better than a Neumman.

Froggy sayin.........well, I don't know what he's saying.

alfalfa,

Great debate!!!

GT

 

[ds21]

alfalfa,
You keep talking about the phase of the first-order crossovers, but you do know that you can also do it with other orders of crossover, plus to get Significantly lower distortion you have to have a very stiff cone which means ringing, which mean more componants in the cossover, plus the distortion of the multiple drivers does add up, plus the intermodulation of the cossover region, and the larger group delays and so on and so on... plus I would like to see some data that says at what point does distortion and of what type of distortion is audible. I'm not taking GT's side that fullrange are the, end all and be all of speakers, just, no mater what design philosophy you choose there are always drawbacks. sound like your caught in the same trap he is(first order)

 

[Recording Engineer]

Being that I know Harvey has had years in the speaker field, I'd sure be interested in what has to contribute to all of this.

 

[alfalfa]

As far as I am aware it is only possible to design a time and phase accurate speaker using first order crossovers, then physical aligning the drivers to compensate for the 90 degree phase shift caused by the crossover (or using no crossover and a single driver as GT suggests). Unless you are talking about digital active speakers (like those by meridian) where the phase shift caused by the crossover can be compensated for digitally.

Higher order crossovers cannot result in a time and phase accurate speaker because the phase shift is too large to be compensated for by physically aligning the drivers and because the phase shift is different at different frequencies. You can see this by looking at the step response of the speaker. It is time and phase accurate if the step response has the a right triangle shape as seen by the earthworks monitor here (click on step):
http://www.earthwks.com/ns/monitors_graphs.html

 

[ds21]

Your need to do more research. I used to think that too.

And here's a review of a good fullrange speaker:

http://www.rlacoustique.com/lamhorn.htm

granted it won't go down to 20.

By the way my latest two-way speaker designs are use fisrt-order crossovers, and they do sound very nice. I tried doing a series first-order but it didn't sound as good as a parallel.

 

[alfalfa]

Could you please show me an example of a time and phase accurate speaker that does not use a first order crossover (ignoring the exceptions I mentioned previously). I really have not come across any and am keen to learn more.

EDIT: To clarify further when I say first order crossover I am referring to a first order acoustic transition between the drivers (which may or may not be implemented with a first order electrical crossover or no crossover at all in some instances). Sorry if there was any confusion or if I am using the incorrect terminology (perhaps I should always say first order acoustic crossover???).

 

[GT]

Could you please show me an example of a time and phase accurate speaker that does not use a first order crossover (ignoring the exceptions I mentioned previously). I really have not come across any and am keen to learn more.

Just when I think I'm out, you guys keep dragging me back in.

Alfalfa,

Doesn't it seem a bit strange, the lengths a two way system has to go to, to achive what a full range has naturally?

Even at it's best, a two way will never achive, the phase coherancy of a good full range. So why even bother?

It seems to me, trying to reinvent a full range sound with a woofer and tweeter, is like well trying to make full range sound, with a woofer and a tweeter.

Two totally different sounding drivers trying to blend, right in the critical midrange area. I ask you, what could be more wrong?

It's like trying to make a silk purse (full range), out of a sow's ear (woofer tweeter).

GT

 

[Recording Engineer]

Question:

Exactly what is the phase phase coherancy degree range we're talking about when it comes to full range speakers that two ways will never acheive?

So what's the story on three ways?

 

[alfalfa]

GT, I dont really want to continue our interesting discussion as we have happily agreed to disagree . My only response to your midrange comment (which has validity) is that a well designed three way speaker with a dedicated midrange driver can overcome that issue. I have already mentioned the limitations of a single driver speaker: intermodulation distortion and either a limited range of frequencies reproduced accurately or inaccurate frequency response over a wide range of frequencies so I will leave it at that.

I await more info from ds21.

 

[GT]

GT, I dont really want to continue our interesting discussion as we have happily agreed to disagree . My only response to your midrange comment (which has validity) is that a well designed three way speaker with a dedicated midrange driver can overcome that issue. I have already mentioned the limitations of a single driver speaker: intermodulation distortion and either a limited range of frequencies reproduced or inaccurate frequency response within that range so I will leave it at that.

I await more info from ds21.

Alfalfa,

I would let it go, but you've made a incorrect statement.

A two or three way speaker also suffers from intermodulation distortion, and inaccurate frequency response. They are not immune.

The proof, no two speakers sound the same, hence inacurate frequency response.

GT

 

[alfalfa]

Yes they also suffer from IMD but their drivers only have to reproduce a limited range of frequencies compared to a full range driver so intermodulation distortion is a much less significant problem. The drivers in a three way should theoretically suffer less IMD than in a two way which again should suffer less than a full range driver (assuming they are attempting to reproduce the same wide range of frequencies).

I did not say all two or three way speakers have accurate frequency responses (most dont) but there are examples that do. My main point was that all speaker designs have inherent problems but I feel the multiple driver issues can be more easily overcome than the single driver issues and I was pointing out the single driver issues that I felt were most significant/difficult to overcome. You feel differently and that is fair enough - neither of us is 'right' or 'wrong'.

Anyway I feel we are repeating ourselves (didnt we discuss these issues before on the first page?). I will let you have the last word.

ps perhaps you and recording engineer can continue this discussion. I will watch from the sidelines until I cannot restrain myself

 

[GT]

alfalfa,

Are you talking about audible, or just measured amounts of distortion.

Audibly, I heard much more apparent distortion, from all the two ways I've had, mostly tweeter related.

My full range sounds much cleaner than any two way I have had.

I think the measure of any speaker, is how long you can live with it, before your wanting something better.

None of the two ways I have ever had, satisfied me for very long.

I allways ended up finding the sound they produced (coloration), to overwelm the sound they were supposed to reproduce.

Tweeters, especially used to drive me up the wall, I found them to be very inacurate. Tweeters to my ears never sounded clean.

alfalfa,

Your restaint won't last long, mine didn't. It's because your pasionate about what you believe, me too. That's good!!

GT

 

[GT]

Since speakers are the weakest link, I think it would be cool to hear what people honestly think about their speakers.

It took me year to find speakers that I really like.

Has anyone else arrived?

Now I will now refrain.

Rock on alfalfa!!

GT

 

[alfalfa]

I was speaking about measured and theoretical IMD. Your personal experiences/observations are perfectly valid (and even more important) and as you said, in the end thats what counts.

I am also keen on hearing what everyone else thinks. Anyone?

ps I definitely agree with you regarding my restraint. Lets see how long I last after this post.

 

[GT]

Question:

Exactly what is the phase phase coherancy degree range we're talking about when it comes to full range speakers that two ways will never acheive?

So what's the story on three ways?

RE,

Phase simply put, is sound eminating from different distances.

Ideally, a single point would reproduce all the sound, keeping the sound eminating from the same distance.

If you want to hear for yourself how real this is. Remove the tweeter from your speaker, leaving it plugged in, and with music playing, move it to and away from you. You will easily hear what sounds like a phasor effect. That's how dramatic it is.

A good full range will not be as affected, because it is closer to the ideal single point source.

Sorry alfalfa, couldn't resist.

GT

 

[ds21]

GT, you made a good point, you can have perfect phase, but just don't move or phase is all screwed up unless the AC stays the same.

Here's the driver used in the speaker review above:

http://www.rlacoustique.com/reps1.htm

Note the distortion, I know doesn't state IM, but pretty good!

alfalfa,
The thing you really want is a "Transient Perfect" design, that way everything will fall into place not only the step response. Somewhere I've got a link to a great site that will explaine all the mumbojumbo, I'll try to find it.

other than posting the link I'm done with this as I agree with both of you, Also you might want to look at the Manger driver, I havn't heard it but it's intresting:
http://www.tnt-audio.com/casse/manger109_e.html

I think this is the best of both worlds no crossover in the vocal area but still great bass. It's on my list of projects too.

I've been spending too much time on this I''ve got 30 CDs to burn and print, plus I'm getting my NT5s tomarrow, time to get back to making music!

 

[alfalfa]

RE, there is a good explanation about time (and phase) coherency on the meadowlark website:
http://www.meadowlarkaudio.com/TC1.htm

Time and phase accurate multi driver designs that do not use a coaxial/concentric design have a restricted vertical listening window. They sound different (and lose time/phase coherence) if you stand up. You have to optimise them for a certain listening height. Most people conduct their critical listening in the same position (sitting on their sofa or in front of their DAW) so this is usually not an issue. But if flexibility is required in the vertical listening position a point source design is recommended. This may be a single driver design that GT is fond of, a time and phase coherent coaxial design (tweeter inside midrange driver) like those used by Thiel Audio or the flat panel design used by the Quad electrostatics (none of the other panel speaker brands are time/phase coherent)

ds21, I look forward to reading that info when you get a chance to find it.

I have read very bad comments from a reviewer I trust about the mangar sound (I believe the words were "musically unnatural" and "worst sound at CES") but I am keen to hear more/alternative opinions. Is it a single driver design? I see a woofer along with the msw and they mention a crossover so it doesnt appear so. EDIT: I just read the review more closely and they describe it as virtually single driver (down to 140hz with a woofer for bass).
It is good to see them provide detailed measurements unlike most speaker manufacturers. I do have to question their frequency response specifications though. They claim +-3db for the m109 but looking at their own frequency response plot shows an almost 10db swing ie +-5db. Are my eyes deceiving me?

ps: I have not responded directly to any of GT's comments. Does that count as restraint?

 

[Recording Engineer]

Thanks guys for pointing me in some directionsI most likely would have never followed on my own.

But my question was specifically, about how much phase coherancy in degrees are we talking about from a good full range that two ways will never achieve? And if I've gathered what has been said correctly, that three ways will never achieve then either?

And while on the subject, anyone know what we're talking about in degrees for the mentioned coaxials by Thiel Audio and flat panels by Quad?