[BobRex]

This is true. All most all of the best speakers I can think of are not phase coherent. In fact I am having trouble thinking of a really good speaker that is. So far I have not seen having a speaker that is time and phase coherent to present an advantage. If you were outdoors (no room reflections) and in a fixed sweet spot then maybe so. Place the speakers in a room and forget it.

Vandersteens - surely you aren't going to claim that the Quattros, 5s, and 7s aren't "really good speakers".  How about the Quad panels?  Then there's the Thiels - at least the CS series.

[LarryB]

BobRex:

I too feel that Vandersteen speakers are excellent, though I have know way of knowing how much this is attributable to their time/phase coherence. 

I used to own Thiel speakers, and they obviously have many fans, but to my ears they are one of the worst speakers on the market - they have a distortion in the upper mids-trebles that I find unbearable.  I am not resorting to hyperbole; I cannot stay in a room with them, as I get headaches.

So my reaction to the two leading time/phase coherent speakers (Meadowlark was a third, but they of course have been out of business for quite a few years) is as different as night is from day; one I think is excellent, the other dreadful.  So obviously, their time/phase coherence is but a small part of their overall sonics.

Larry

[Danny Richie]

Vandersteens - surely you aren't going to claim that the Quattros, 5s, and 7s aren't "really good speakers".  How about the Quad panels?  Then there's the Thiels - at least the CS series.

The funny thing is that a couple of those speakers sound completely opposite of each other.

I have to agree with Larry about the Thiels to some degree. I attribute much of their characteristics to their choice of materials. They are simply hard for me to listen to for very long. They have an edge to them or harshness that I can't stand. Sometimes even having a bit of a ring to them.

The Vandy's remind me very much of the Dunlavy's. I have upgraded a bunch of those Dunlavy speakers. With the stock crossover they always sounded a bit soft as if each peak was rounded over. Detail levels that I am used to are a bit smeared and resolution levels are just not there. I typically replace all of the smaller caps with Sonicaps, by-pass the larger Solen poly caps, and replace all of the resistors with Mills. Upgrading the wiring really helps to. After that they sound like a different speaker. Resolution levels and finer detail levels are then back up to near my usual standard.

So the time and phase coherency deal is often easily overshadowed by other issues. It is barely a spec in a really large picture. 

[DS-21]

Just so that we understand where you are coming from, would you care to share with us what you consider a high-fidelity speaker?

I will say the only speaker on your website that has any shot of passing muster with me would be a closed-box version of the Super-V, with the voodoo nonsense taken out (don't care about brands of caps, wires, input terminals, etc.).

My current reference system uses 12" Dual Concentrics out of Tannoy System 12 DMT II speakers, in a low-diffraction closed-box cabinet I commissioned from Nathan Funk. While they currently use passive crossovers, I recently picked up an 8x8 miniDSP, and will actively biamp them when I move (early-mid August).

If a KEF dealer would sell me three of them (as opposed to making me buy two pairs and sell the unneeded speaker) I would probably run KEF Reference 201/2's. They don't have the dynamic snap of the big Tannoys, but except for that they do nothing remotely wrong, and they're a lot nicer to look at.

Underneath them is a Geddes-style multisub system that uses four Aurasound NRT-motor underhung drivers in closed boxes.

I also have some commercial speakers from KEF that use their Uni-Q coincident driver.

Still it is not hard to get a very consistent in room response from a typical boxed speaker design. And it is not hard to get a very consistent off axis response either.

It's hard on the first part. And only possible in a tiny area of the room. (I'm not a head-in-a-vise kind of listener, though others may be.) As for the latter, sure if one considers a mushroom cloud of midrange energy "consistent."

[Freo-1]

This is true. All most all of the best speakers I can think of are not phase coherent. In fact I am having trouble thinking of a really good speaker that is. So far I have not seen having a speaker that is time and phase coherent to present an advantage. If you were outdoors (no room reflections) and in a fixed sweet spot then maybe so. Place the speakers in a room and forget it.

 
Guess you have never heard these then:
 
http://www.sourcespeaker.com/Coherentpulse61a.html
 
They sound outstanding.

[Danny Richie]

I will say the only speaker on your website that has any shot of passing muster with me would be a closed-box version of the Super-V, with the voodoo nonsense taken out (don't care about brands of caps, wires, input terminals, etc.).

  First of all I have had those drivers in a sealed box and a ported box. They are not even close to what they can do in an open baffle. Plus as soon as I modded the tweeter to make it an open baffle driver as well, it completely transformed the speaker. The highs are much more relaxed and natural now. With the rear cup on it the highs were more compressed and strained.

Un-boxing that driver opened it up and relaxed the mid range. It made all more transparent. Instruments sound like they are really there in the room verses playing from a box.

And all of that so called voodoo is really well proven results across the board. If you are one of those guys that thinks caps are caps and wire is wire then you are really missing out, and have a lot to learn.

I am willing to really help you out though. Take this challenge: http://www.audiocircle.com/index.php?topic=87808.0

I'll help you even more.

I recently picked up an 8x8 miniDSP, and will actively biamp them when I move (early-mid August).

Those DSP devices have no place in high end audio. They literally suck the life out of the music. They have about the same quality levels as a CD player bought from Walmart for $99. They may be fun to play with and perfect for an entry level system, but that's about it.

Guess you have never heard these then:
 
http://www.sourcespeaker.com/Coherentpulse61a.html
 
They sound outstanding.

I have not heard of those speakers.

I have used those woofers a lot and am not a big fan.

Also, looks like a top of the speaker hangs over the tweeter quite a bit. That can cause a pretty bid disruption to the tweeters response. That would not be a good idea. 

[Freo-1]

 
 

Those DSP devices have no place in high end audio. They literally suck the life out of the music. They have about the same quality levels as a CD player bought from Walmart for $99. They may be fun to play with and perfect for an entry level system, but that's about it.

I have not heard of those speakers.

I have used those woofers a lot and am not a big fan.

Also, looks like a top of the speaker hangs over the tweeter quite a bit. That can cause a pretty bid disruption to the tweeters response. That would not be a good idea.

Two responses:
 
1) I am a fan of those woofers.  They will expose the upstream electronics for what they are (good or bad).  If your input to them is good, then the sound is outstanding (a combination of planar speed and dynamic slam). 

2) John Sollecito is one of the chief designers of this speaker.  This guy knows his stuff.  He previously was involved with the JSE Infinite slope speakers, which were very good sounding.  The Source Technology line is all excellent sounding, and this one is one of his best.
 
Guess your response explains why there are so MANY different speakers out there.
 
PS: I agree with the DSP comment you made.

[Danny Richie]

1) I am a fan of those woofers.  They will expose the upstream electronics for what they are (good or bad).  If your input to them is good, then the sound is outstanding (a combination of planar speed and dynamic slam). 

I test woofers all the time. I even design a lot of woofers. I have used those woofers and I have designed higher quality replacements for them for one of my commercial clients. The Excel woofer to me has a very artificial sound to it. The mid-range is a bit veiled and un-natural. It also has a ring to it because of the sever break up in the upper ranges. An elliptical network is about the only way to control the ringing in the upper ranges.

2) John Sollecito is one of the chief designers of this speaker.  This guy knows his stuff.  He previously was involved with the JSE Infinite slope speakers, which were very good sounding.  The Source Technology line is all excellent sounding, and this one is one of his best.

Well, he either doesn't realize the effects that the overhang causes or is aware of it but disregards it. It will without question cause a lot of diffraction that will disrupt the response considerably.

Here is an example. I designed a crossover for one of my clients that had a slight overhanging top plate. The grill fit flush under it and looked nice, but it certainly effected the response.

Here is a pic of the prototype that was sent to me for crossover design.



Here it is after I whacked off the overhanging top.



And here are the measured differences, before and after.



Care to guess which is which?

Imagine if it were closer to the tweeter and even longer. I am guessing that the overhang on the speaker that you sent a link to can cause a 10db or greater swing in the response.

[Danny Richie]

1) I am a fan of those woofers.  They will expose the upstream electronics for what they are (good or bad).  If your input to them is good, then the sound is outstanding (a combination of planar speed and dynamic slam). 

FYI, that woofer has a moving mass of 15.5 grams. http://www.madisoundspeakerstore.com/seas-woofers-6-7/seas-excel-w18e-001-e0018-7-magnesium-cone-woofer/

The one that I replaced it with using a similar motor structure but a paper cone has a moving mass of only 11 grams.

Care to guess which is really closer to having planar like speed?

[srb]

Here is an example. I designed a crossover for one of my clients that had a slight overhanging top plate. The grill fit flush under it and looked nice, but it certainly effected the response.

Here is a pic of the prototype that was sent to me for crossover design. Here it is after I whacked off the overhanging top.

From another topic you stated you designed these for another client.  It looks like these speakers would exhibit the same problem.

[Freo-1]

The comparison you provide is a bit of “apples and oranges”, in that the tweeter you measured vs. the one in the Coherent Plus are completely different.  I’m sure the recessed tweeter is “by design”.  The crossovers are also quite different.  Perhaps you (or I) should ask him about why it is so.
 
As to the Excel woofers, (I) do not hear what you talk about.  I do hear clarity of sound that is very natural “provided” the upstream electronics are up to task.  When using a mid fi component, the speakers can expose their shortfalls.  However, connect a higher end tube amp of Class A solid state amp, and they sound outstanding.  Since they are very widely used, a lot of other folks must enjoy them as well, or they would not be used in as many speakers as they are.

[Danny Richie]

srb,

That one has a rounded and stepped top plate rather than a flat one and it's effect is not as bad. Still there are some effects to the response from it being there. With the grills on (which has a radius on the inside edge of the grill) the effect of the top is no worse than the same effect that any speaker grill has on any other speaker.

It's not like having a 3" long flat surface right over the tweeter though.

[Danny Richie]

The comparison you provide is a bit of “apples and oranges”, in that the tweeter you measured vs. the one in the Coherent Plus are completely different.  I’m sure the recessed tweeter is “by design”.  The crossovers are also quite different.  Perhaps you (or I) should ask him about why it is so.

Diffraction is diffraction there is no changing the physics of it. You can try and compensate for it with the crossover but it doesn't make it go away.

Ask him about it if you like, but I am sure he is not going to provide a response curve with and without it there so that the result can be seen.

As to the Excel woofers, (I) do not hear what you talk about.  I do hear clarity of sound that is very natural “provided” the upstream electronics are up to task.  When using a mid fi component, the speakers can expose their shortfalls.  However, connect a higher end tube amp of Class A solid state amp, and they sound outstanding.  Since they are very widely used, a lot of other folks must enjoy them as well, or they would not be used in as many speakers as they are.

Actually, when you step up to the level of electronics that I use then their short comings become quite apparent. They are just simply not up to the performance level of what I am used to listening to and I just don't care for them.

And Bose is also widely used and enjoyed.

[Rclark]

 Back to those original speakers, those CD horn things, would those be considered superior to the Geddes design, or just different? And is there any accessible way to make a pair or are you supposed to be of a certain level and reverse engineer it on your own?

 Reading about them, and seeing stacked arrays in the living room makes them seem like a nice high end alternative choice.

 The one gentleman, Paul I think, was able to show that they are of a high performance level.

[johnzm]

  that bose comment is particularly funny...

I hope this thread is not pissing you off Danny, it seems it is growing past the original intentions.

BUT I will admit I am enjoying the dialog.  I learn something new in this forum every day!

and secretly, I am hoping someone who owns a pair of these lives close enough to Danny that he can measure it.

but back to the topic, Danny, in your opinion is it even worth the time to persue a design like this?  It seems like alot of diy'ers are really looking at the good qualities of this design (possibly ignoring the poor qualities). could this design shine with quality drivers and a well designed network?

[Freo-1]

Actually, when you step up to the level of electronics that I use then their short comings become quite apparent. They are just simply not up to the performance level of what I am used to listening to and I just don't care for them.

And Bose is also widely used and enjoyed.

Comparing Excel drivers to Bose might be good copy, but not true at all.
 
So, how does one measure the sub-optimum response you state?  If it’s by hearing alone, then this discussion is pointless.  At that point, it’s a matter of opinion (and you know what they say about opinions). 
 
If you have actual graphs that demonstrate this behavior, (as in distortion and non linearity), that would be enlightening.  Could you provide an example of a commercially made woofer that would provide a improved performance?
 
PS: You have piqued my curiosity about the Coherent speakers, so I’ll ask John about the design, and mention your comments about it.  Since I’m sure he designed it that way, I’m interested in his thinking on this.

[Danny Richie]

Rclark,

I don't see them as a high end alternative or even a consideration. If I needed to fill an arena sized area with volume though maybe so.

I would really like to hear them though. I am really open minded to this stuff. I have been surprised before.

Johnzm,

I don't mind the discussion at all, and even when the discussion moves around a bit that's still okay. Sometimes discussions like this allow interesting information to come forth.

I wouldn't pursue a design like this for myself or any of my customers. It just fails outside of any market area that I deal with. Even if I were to design something for an arena sized room or stadium I don't know that I would go this direction either.

And I am sure that more could be done with the design if someone wanted to take it to another level. Just higher quality crossovers and a heavier well braced cabinet could go a long way. Even lining the back side of the horn and inside of the box with No Rez would really help. It won't help the wife acceptance factor any. And they still need subs...

If you guys want to tweak on these things I'll be glad to help.

Hey even a bunch of those guys building the Gedlee Abbey speakers were buying Sonicaps and No Rez from me. So I don't mind helping you guys out with any of this stuff. I am in the speaker upgrading and parts supplying business.

[Freo-1]

FYI, that woofer has a moving mass of 15.5 grams. http://www.madisoundspeakerstore.com/seas-woofers-6-7/seas-excel-w18e-001-e0018-7-magnesium-cone-woofer/

The one that I replaced it with using a similar motor structure but a paper cone has a moving mass of only 11 grams.

Care to guess which is really closer to having planar like speed?

 
That’s easy:  SEAS Excel, due to the following:
 
“Strengths are: Best available transparency, imaging, and depth presentation of any type, equaling or exceeding electrostats if carefully designed.  High efficiency, high peak levels, and very low IM distortion in the best examples. This class of drivers is considered at the state of the art by many designers, and this field is expected to advance quite rapidly as material technology advances.”

 
So, they cost more. Oh well.

[Danny Richie]

Comparing Excel drivers to Bose might be good copy, but not true at all.

I was only comparing them in regards to you stating their popularity. Obviously they are not in the same performance league.

So, how does one measure the sub-optimum response you state?  If it’s by hearing alone, then this discussion is pointless.  At that point, it’s a matter of opinion (and you know what they say about opinions).

 

The stored energy, break up, and ringing effects are clearly seen in the frequency response and spectral decay.

Subjective comparisons are no less valid. Just as many of you guys listen to and compare speakers I do the same thing with drivers. If we only went by the numbers then we could just buy a speaker by the numbers. Funny thing is that I can make one measure great that still sounds bad.

If you have actual graphs that demonstrate this behavior, (as in distortion and non linearity), that would be enlightening.  Could you provide an example of a commercially made woofer that would provide a improved performance?

Distortion numbers are not where it is at. For one, there is not even any industry consistency in how that are measured. Secondly, those measurements made outside of an anichoic chamber are not even valid. Plus hearing differences between 1/2% and 1% or between 1% and 2% is next to impossible with music material.

If there is one measurement that really tells you something about how it will sound it is the spectral decay. Stored energy varies a lot from driver to driver and is easily heard.

And I can easily provide you with examples of woofers that sound much better then the comparable Seas Excel. I designed some for a client. I wouldn't say that they are commercially made or available though. They were custom built.

Old product line using Seas Excell drivers:













Their new product line can be seen here:  http://www.tyleracoustics.com/Decade.html

Here is a sample pic:



And quite a few people have upgraded from one of the older models to one of the newer ones. Care to guess which line sounds better? I can assure you that the new product line would not have been released if it didn't provide a considerable step up in performance over the older one.

[Danny Richie]

That’s easy:  SEAS Excel, due to the following:
 
“Strengths are: Best available transparency, imaging, and depth presentation of any type, equaling or exceeding electrostats if carefully designed.  High efficiency, high peak levels, and very low IM distortion in the best examples. This class of drivers is considered at the state of the art by many designers, and this field is expected to advance quite rapidly as material technology advances.”

So, they cost more. Oh well.

Transparency, imaging and depth are not qualities of the drivers. Those qualities are all due to other things. And sensitivity is rather low for the entire line.

Ever look at ads for home theater receivers and see distortion numbers listed like .1% .05% and .001% blah, blah, blah... Do you think the differences in sound quality have anything to do with those numbers? I'll answer it for you. They do not. And the same holds true for drivers. A distortion test can highlight a problem if there is one, but differences in sound quality can not be related to slight variations in distortion numbers.

Exotic materials do not equal performance either. Most of the exotic cone materials have poor internal damping and response problems. Most companies use them more for advertising than anything. Ever see an add that says "Kevlar - what bullet proof jackets and our speakers have in common"