ZU Cubes with some love from GR Research

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jparkhur

ZU Cubes with some love from GR Research
« on: 4 Jan 2016, 07:53 pm »
Zu Cube
I have been behind and am now just getting to this.  I received some ZU Cubes at a very good discount/b stock left overs rate from them this past fall.  They were unmatched cabinets and this may or may not account for some of the assembly.  I knew I wanted to mess with the little 10 inch box coaxial speaker for fun.  I had heard much about the company and liked their views on some aspects of audio.

This is not a hit on Zu or anything else beside a look at what people can invest in if they choose.  Zu picks a price point and is in the business of  making a profit and providing a certain speaker with specific market points etc. 

I knew I would have to coat the boxes with Dura Tec and took two different mismatched speaker cabinets knowing this, and would put my time in to adding a xo to smooth things out.  When I first got these speakers I let them break in for some time and noticed a lack of low-mid bass and the highs where even to much for me.  Looking at the freq plot supplied by the company and professional reviewers I noticed the real high end peak and a drop out towards the top (later was told that was due to the throat of the coaxial).  It is a nice sounding speaker for some, so I dropped it off to Danny and told him to go nuts.  I kept one in original form to do a side by side comparison in the end.

We started with the following parts.  Pictures are self explanatory.






The inside of the box was like what you see above, the wire was attached with clips and not soldered, and the speaker inputs were jammed in and included no nut on the side to keep them from being pulled out.



After the xo was put together by Danny, this is what was the outcome.  It is much smoother and from the various waterfall graphs you can see the cleaner response etc.  (Danny feel free to add the tech stuff here.)  I lined the boxes with No Rez all around and build the p2p XO on a separate sheet of 1/8 inch board and set it in the bottom of the box.  There was a set of GR speaker connectors added and the entire box was covered in Dura Tec with a 3/8 inch nap roller.  I added three coats to make sure it was even.  I love this stuff because it is so easy to NOT screw up.. 


















The cost object on this project was more than I thought it would be, but that is me.  There were 13 different parts to the XO to get the speaker to respond better.  This would go against the views of Zu and their message for audio and you may be better off selecting different parts to make it a more economical build.  I was a little discouraged with the fact that the actual drivers were for the most part off the shelf at PE put in to a 10 inch box with a single cap.  From a consumers perspective this was a huge markup without the audio benefits.  I get it, people got to make money, but there was not any engineering involved in this build at all, and for 999 dollars retail, i could certainly buy other speakers on the AC site that would kill them in performance.

Feel free to add your thoughts etc.  No offense taken from me, it was a one off trial project for me.  I can now built these for a couple hundred bucks..  Thanks for reading....

poseidonsvoice

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Re: ZU Cubes with some love from GR Research
« Reply #1 on: 4 Jan 2016, 08:10 pm »
Remember the review of the Zu Essence from stereophile years back? :duh:

http://www.stereophile.com/content/zu-essence-loudspeaker-measurements#vAFb8Y7LQlMkiO52.97

Best,
Anand.

jparkhur

Re: ZU Cubes with some love from GR Research
« Reply #2 on: 4 Jan 2016, 08:19 pm »
I do, and so these reviews are off too... 

http://www.soundandvision.com/content/zu-audio-cube-speaker-system#XWFQyusde2DoVt7L.97

http://parttimeaudiophile.com/2013/08/19/cas-2013-zu-audio/



http://www.ultrahighendreview.com/zu-audio-cube-speaker-system/

Not sure how these guys all came up wrong, but said they were right.  Guess we all hear things differently... 



Part-Time Audiophile

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Re: ZU Cubes with some love from GR Research
« Reply #3 on: 4 Jan 2016, 09:59 pm »
I do, and so these reviews are off too... 

...

Not sure how these guys all came up wrong, but said they were right.  Guess we all hear things differently...

I'm not sure I follow? Came up "wrong"? Or that the observations made didn't line up the way you'd expect them to, following the measurements that were taken (http://www.soundandvision.com/content/zu-audio-cube-speaker-system-test-bench)?

FWIW, Mal was talking about the Druids, not the Cubes, but the point could still be made (more like "extrapolated", perhaps) that since the measurements of those two speakers were "suboptimal" (at least according to the expectation seemingly embedded in the thread here), how could anyone hearing them not immediately leap to their feat, fingers squeezing their nose closed while shouting "J'accuse!"

... which is nonsense.

I will offer that there are a great many extraordinary loudspeakers from companies with apparently impeccable reputations that measure to a fare-thee-well, yet have a remarkably narrow fan base. Conversely, there are legions of fans behind brands that put together devices that, prima facie, would seem absurd -- given their measurements.

Why is that?

You don't have to construct a psycho-acoustic theory to explain harmonic preferences, nor one that incorporates "sour grapes", nor "age-related infirmity", nor one about "the tyranny of numbers". This is aesthetics. There is no "right". There is only "preference".

Robert Parker is a big fan of French Bordeaux -- and is a world renowned expert on the subject of the quality of wines produced there. The fact that you like California Merlot is regrettable, but not interesting to Parker. Nor will your experiences on the delights of that grape be anything other than academically interesting to Parker, who will -- rightfully -- shrug at your lamentable taste.

Guttenberg is a fan of Zu Audio. Why? Who cares -- the fact is, he is, and that is all.

So, if you're expecting a review to be a universal, a can-opener on the wonders of things you cannot yourself experience directly, I regret to say that this expectation will probably not serve you very well.

But I for one am always interested in upgrades to existing products. I think this project is neat and Danny is a wizard. But the "proof in the pudding is in the eating" -- who cares how much better it measured (I mean, I guess that's nifty and all): did the upgraded units sound any better, and if so, how?

jparkhur

Re: ZU Cubes with some love from GR Research
« Reply #4 on: 4 Jan 2016, 10:19 pm »
Part time. Your words are well spoken and insightful.  A mastery of the English language.  Nice Scot

I like to see things as well as hear them and the visuals are just a place to start with the discussion of upgrading items

Part-Time Audiophile

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Re: ZU Cubes with some love from GR Research
« Reply #5 on: 5 Jan 2016, 12:38 am »
Kind of you to say. But do let us know how your testing progresses. Again, neat project -- thanks for sharing.

Danny Richie

Re: ZU Cubes with some love from GR Research
« Reply #6 on: 5 Jan 2016, 01:11 am »
I'm not sure I follow? Came up "wrong"? Or that the observations made didn't line up the way you'd expect them to, following the measurements that were taken (http://www.soundandvision.com/content/zu-audio-cube-speaker-system-test-bench)?

FWIW, Mal was talking about the Druids, not the Cubes, but the point could still be made (more like "extrapolated", perhaps) that since the measurements of those two speakers were "suboptimal" (at least according to the expectation seemingly embedded in the thread here), how could anyone hearing them not immediately leap to their feat, fingers squeezing their nose closed while shouting "J'accuse!"

... which is nonsense.

I will offer that there are a great many extraordinary loudspeakers from companies with apparently impeccable reputations that measure to a fare-thee-well, yet have a remarkably narrow fan base. Conversely, there are legions of fans behind brands that put together devices that, prima facie, would seem absurd -- given their measurements.

Why is that?

You don't have to construct a psycho-acoustic theory to explain harmonic preferences, nor one that incorporates "sour grapes", nor "age-related infirmity", nor one about "the tyranny of numbers". This is aesthetics. There is no "right". There is only "preference".

Robert Parker is a big fan of French Bordeaux -- and is a world renowned expert on the subject of the quality of wines produced there. The fact that you like California Merlot is regrettable, but not interesting to Parker. Nor will your experiences on the delights of that grape be anything other than academically interesting to Parker, who will -- rightfully -- shrug at your lamentable taste.

Guttenberg is a fan of Zu Audio. Why? Who cares -- the fact is, he is, and that is all.

So, if you're expecting a review to be a universal, a can-opener on the wonders of things you cannot yourself experience directly, I regret to say that this expectation will probably not serve you very well.

But I for one am always interested in upgrades to existing products. I think this project is neat and Danny is a wizard. But the "proof in the pudding is in the eating" -- who cares how much better it measured (I mean, I guess that's nifty and all): did the upgraded units sound any better, and if so, how?

Dear Part Timer,

I am a full time loudspeaker designer.  :green:  This is what I do day in and day out. I design products for other companies, my company,  and I upgrade speakers. I upgrade a LOT of speakers. Speaker upgrades are well into the hundreds now. So let me break things down for you in a more understandable way. And for everyone reading along as well.

There are subjective things. Tonal balance for instance is very subjective. I can shift it a little here or there, at the top or in the middle. Capacitors tend to have a specific sound or signature too. Some are a little soft and smear the signal just a hair. Others are faster and cleaner. Some like one, some like another. Wire, connectors, material preferences all have an effect and can have a subjective favor. And when a designer designs his products he makes certain choices based on their subjective preferences. And some will like them and some will not.

That isn't what an upgrade like this is about.

I look at all the things that aren't supposed to be there. I look at things that are not about preference or choice. I look at all the things that color the signal in an unnatural way. Sometimes they are left there out of ignorance. Sometimes these things are about cost and compromise. Regardless of the reason, I solve those problems.

Now in the case of this speaker there were what I call problems that are solved that have nothing to do with any subjective preference. Here are some of them.

Look at the response curve that John posted. It matches this one taken by Sound and Vision.



The dipped area at 4kHz is due to the woofer and the tweeter both covering that range but being out a phase. By being out of phase they cancel each other out and cause a hole. That is a problem that is easily fixed. It is not a subjective issue. There is not supposed to be a hole there. There is no preference in making a hole there.

Now the hole in the response that is centered at 15kHz is from throat cancellation in the tweeter. To fix that requires reshaping the throat and maybe adding a damping ring to absorb a little at a given frequency to do away with a cancellation effect there. I can't fix that. It is driver related.

Now look at the spectral decay. There is a ton of stored energy there. It is heard as an excessive ringing and smearing. It is not subjective or about preference. It is a problem. Some of this problem can be fixed. The ringing in the upper ranges is from woofer break up. This can be controlled by a proper crossover. The long decay rates in the lower region that look like they pop up from an area that was already down is the result of internal cabinet reflections. This colors and smears the sound considerably and is very easy to hear. Again this is not about preference. It is a problem. The cabinets were not properly damped. A small block of foam doesn't work. It might be economical from a production stand point, but it doesn't cut it. Lining the cabinet with No Rez and using a little additional damping solved this problem. See the latter much cleaner spectral decay.

There was also no baffle step loss compensation as there was no filter on the woofer at all. So the response fell off quickly below 700Hz or so (500Hz on the Sound and Vision measurements). This is not a matter of preference or taste. It is unnaturally low in output because there is no compensation for it. The new network that I designed did compensate for it and produced a smoother and more balanced response. It is not a subjective matter. Mid-range and bass areas are not supposed to be rolled off.

Thin un-braced cabinet walls resonate. It colors the sound. It isn't about subjective preference. It is not part of the input signal. Lining it with No Rez killed the resonances of the cabinet panels and took away that coloration.

Slip on connectors (made from Tin), cheap binding posts, and wire all have a effect on the signal. It degrades it to some degree. No one ever thinks that degrading the signal a little would make them sound better. It is an economical choice to use those things. Upgrading to tube connectors, higher quality wire, and soldering the drivers straight to the wire with no additional connectors all improve signal transfer and improve the sound making everything (top to bottom) much cleaner. 

Lots of things can simply be improved unequivocally, and without subjective considerations because it is a matter of solving or fixing a problem.
« Last Edit: 5 Jan 2016, 04:50 am by Danny Richie »

bdp24

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Re: ZU Cubes with some love from GR Research
« Reply #7 on: 5 Jan 2016, 03:43 am »
I am SO glad you wrote the above, Danny! The notion of everything in Hi-Fi being merely subjective, a matter of taste and preference, is completely wrong-headed, incorrect, and dangerous. That is not what J. Gordon Holt had in mind when he invented "subjective" reviewing in the early 60's. No, specs aren't the whole story, but to ignore poor measurements, and more importantly, the failings in design from which they, and poor sound, result, does not well serve the cause of improving the reproduction of music. To proselytize that poor measurements and poor sound are unrelated is simply very much mistaken, for reasons Danny just so well outlined.

Early B.

Re: ZU Cubes with some love from GR Research
« Reply #8 on: 5 Jan 2016, 04:58 am »
I am SO glad you wrote the above, Danny! The notion of everything in Hi-Fi being merely subjective, a matter of taste and preference, is completely wrong-headed, incorrect, and dangerous. That is not what J. Gordon Holt had in mind when he invented "subjective" reviewing in the early 60's. No, specs aren't the whole story, but to ignore poor measurements, and more importantly, the failings in design from which they, and poor sound, result, does not well serve the cause of improving the reproduction of music. To proselytize that poor measurements and poor sound are unrelated is simply very much mistaken, for reasons Danny just so well outlined.

As you mentioned, much of what was measured was common sense speaker building and building to a cost point. Specifically, the measurements showed that the cabinet was weak and not properly lined, and the design used minimal crossover parts and cheap parts throughout. The subjectivity arises when people enjoy how a poorly designed speaker sounds, in spite of its cheap parts and lousy measurements. In fact, 99% of people love the sound of poor speakers. Only technically-oriented audiophiles want to see "proof" that their speakers measure up. So, yeah, poor sound is measurable, but it's only speaker designers and a handful of audiophiles who actually care about it.

Folsom

Re: ZU Cubes with some love from GR Research
« Reply #9 on: 5 Jan 2016, 07:58 am »
It seems clear the sensitivity goal is to high, to me. It's also a bit backwards to have a crossover on the tweeter, but not the woofer... The reverse is much more preferable if you can achieve it.

What gives them the sound people like, I wonder?

To me it seems like "interesting" speakers are making up for lacking electronics.

undertow

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Re: ZU Cubes with some love from GR Research
« Reply #10 on: 5 Jan 2016, 04:18 pm »
Ah yes the old' Zu saga continues...

Truth is these guys are good at what they do, great customer service... They were that last great speaker hope that was early enough in the audio game with internet sweeping the nation in the year 2000 which afforded them some good exposure, and success. Timing was everything in this game.

Just under the wire they might be the last of the American branded speakers to do what today would be impossible for any startup because the last thing we need is another kitchen table speaker company trying to make it big. No room for that, and the industry is well over saturated as it is with used good speakers, and nearly impossible marketing costs.

However, what is my point?

Not sure where the surge of "Utah" based speaker companies came from in the early 2000's, I guess Dave Wilson "also Utah based Wilson audio" inspired them all to attempt building based on a model with strong enough marketing, and enough cutting edge gimmicks to make them different. Overcharge enough to make it seem like a serious product, but not to much to force them into direct competition with all the major legacy companies.

Well Zu did achieve that even without perfect product, or sound. I give them props for pulling off the near impossible. But truth is they filled a niche' almost everybody missed. Semi-compact, high efficiency, semi-affordable speakers.

That being said what I find interesting is another company in link below based also in Utah on a similar philosophy using pro audio guitar drivers, but much more toned down, and honestly looks like they have accomplished very good 95 and 98 db designs for PENNIES compared to even Zu. Not with the Ferrari finishes, but who needs that when your serious about audio?

By the way with the Zu cubes above needing stands, and a lot of work these below seem a much better bet for the same price, and actually I have never heard them, but man for the pricing all the way up to their big 1812 monsters seems like a very killer value, plus looks like there is plenty of crossover to play with in these, and upgrade to your favorite exotic caps.

http://www.tektondesign.com/lore.html

http://www.tektondesign.com/1812.html

jparkhur

Re: ZU Cubes with some love from GR Research
« Reply #11 on: 5 Jan 2016, 04:58 pm »
With regards to sound and experiences, here is what I have encountered.

Prior to the XO being installed there was some noticeable break up of the sound in the higher midrange and then moving in to the tweeter freq. area.  I find this also on other full range drivers when you try to drive them to higher levels of output.  With the XO installed, this has gone away, with the only item I notice is the high freq is somewhat muted in the range, possibly due to the physical throat the tweeter has to play through.  I have a preference for the NEO 3 and its smooth range ability and second would be the T26SG Tweeter I have had lots of time with.  If you could use the LGK driver just on the high end (which is being done another models) it is similar to the NEO 3 in my listening.

The response on and off axis of the Zu prior to the xo was very specific and narrow.  This has widened some, but as soon as you get off about 30 degrees you lose much of the high end information coming from the tweeter even with the XO.

Imaging is much better with the XO.  I can sit and place instruments easier and they have wider separation using Neil Young's Massy Hall recording and some songs from Nirvana's MTV unplugged album.  I use these examples for myself because I also have visual representation of where the actual instruments are being played from to help confirm what I am hearing.  By no means are these audiophile quality recordings but help in the process.

I knew these would need some lower end reinforcement and have paired them with some free Klipsch SW 8 subs.  I currently have build wedge shape stands to have them sit on the subs, but rake them back about 3-4  degrees-the stance is similar to a Klipsch Heresy speaker and will fit well in the final resting spot which is up against a wall with a hipped roof line coming down - thus the lower form factor works well.

Hope this helps.

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Danny Richie

Re: ZU Cubes with some love from GR Research
« Reply #12 on: 5 Jan 2016, 05:49 pm »
Here is the difference in the off axis John is referring to. This is also not a matter of subjective preference. This is about actual output levels in the off axis. This is the stock speaker:



The off axis falls off quickly because the upper regions are being covered by a 10" woofer. Have a good look at the Yellow line that is 20 degrees off axis and you'll see that it already has a very limited upper end output.

Now compare to the version using the crossover that I designed. The tweeter is now covering the upper ranges so the off axis response is much more balanced.



They will now load the room a little more evenly and offer a more balanced in room response.

Coldfusion

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Re: ZU Cubes with some love from GR Research
« Reply #13 on: 6 Jan 2016, 01:53 am »
What was the cost to go from before to after?

And what off the shelf PE woofer is that?  Do they hollow out the middle or something?   Zu woofers have a look to them that I think attracts people as much as anything else.

undertow

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Re: ZU Cubes with some love from GR Research
« Reply #14 on: 6 Jan 2016, 02:48 am »
Coldfusion,

That is a coax driver, not "hollowed out" simply the tweeter is mounted in the center of the woofer cone so what you see in the photo is actually 2 independent drivers mounted to a single frame with the tweeter in place of the dust cap. Yes normally parts express carries these under pro audio speakers for like PA systems, I believe this specific one is made by Eminence which is still located in the U.S. They probably retail between $40 and $60 bucks.

As for zu's implementation this I believe is the only model they are specifically using this type of Coax in. The other bigger model speakers they build use a similar woofer, but it's another version of the same Eminence woofer that they then cut their own "aluminum phase plug" mounted inside the wizzer cone also in place of the dust cap, however then mount a totally separate tweeter in their cabinet.

jparkhur

Final resting spot w/ PS Audio Sprout
« Reply #15 on: 22 Jan 2016, 09:49 pm »
Thank you Danny for the help with these.  Your Rush is in the mail




jparkhur

Re: ZU Cubes Clones
« Reply #16 on: 4 Oct 2016, 04:02 pm »
Taking the information Danny provided and what is on the inside of the box when opened up, I created a clone Zu Cube for my youngest son using the following from PE.  There is no wizzer cone on the driver, but the sound is significantly similar to the original Zu Cube.  The box is 1/2 left over material, 10.5 inches square, coated with dura tech, lined with No Rez remnants  and painted by the youngest.  I used solid core wire for hook up and the single inline cap for the tweeter.   When you compare the two speakers, one with and without xo, there has been no one that picked the speaker with the single cap in it as the best sounding.  They all gravitated to the speaker with the xo for multiple reasons, but many noted the top end sounded better.. Cost was 180, plus I had credit at PE, so 100 bucks for me and my parts.  I am not a fan of the blue tinted woofer... Not sure why it is not black....

Eminence Beta-10CX 10" Coaxial Driver   
Eminence ASD1001 1" HF Titanium Horn Driver 1-3/8"-18 TPI




undertow

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Re: ZU Cubes with some love from GR Research
« Reply #17 on: 4 Oct 2016, 04:08 pm »
jparkhur,

Although I will agree on a general basis that most of the time even a "Full range driver" design like this will benefit from a bit of finesse using a decent crossover fact is your not comparing a basic Eminence driver in this case.

Zu does blow their drivers apart and re-tune them in the first place to work more with the single cap protecting the tweeter only. From my understanding the newer versions of Zu drivers take it a few steps further, with their "Nano" fluids etc... on the cone controlling more of the anomalies.

This does not matter to explain what you are hearing, but the Zu design ultimately is not as simple as taking a stock full range un-tuned eminence driver from my understanding.

jparkhur

Re: ZU Cubes with some love from GR Research
« Reply #18 on: 4 Oct 2016, 04:14 pm »
The data and info for the start of this thread says much about what is being heard.  I guess I should measure them both to see what the data says.  My uneducated guess is that they are extremely similar.  The tweeter is not messed with only the woofer, but from what I can see, only the xmas was changed... I be willing to see what the graph shows.   

Im not old enough for a pinto...  :P

undertow

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Re: ZU Cubes with some love from GR Research
« Reply #19 on: 4 Oct 2016, 04:16 pm »
Well in your photos you can see the gray style cone from eminence, Zu does not use those 25 dollar versions. Again I am not defending it one way or the other, but its not just the "Same" is all I am saying. However, there is a company that does do exactly as you just did using those basic eminence coax drivers.... Also from Utah!