Hey, karl_desch, I must say you piqued my curiosity as I have the Quatro Wood CTs with the M5-HPA amps. Usually, before I jump to listen, I let JA give insight into his measurements. I know that measurements don't tell everything, but because you say they may compete with the Quatros, I was curious to see if they are similar to the Quatro. Although they have not measured this speaker, they have the more expensive sibling with the exact driver. I was pleasantly surprised to see the impulse response was time and phase correct. It appears relatively easy to drive and should respond well to the M5-HPA, as you mentioned. Then I saw the waterfall plot. To quote JA, it is "awful." I see chaos where there should be order. He then goes on to explain that it is still pleasant to listen to. I have chased this tail where the harmonics are interesting and tantalizing, but the Quatro CTs measurement let me know I have an accurate transducer, which I spent way too much time and money to get to. I am not sure I can listen to what seems to be a lot of noise. That doesn't mean I won't go and listen because a fellow Quatro owner likes them, but I don't have to make it a rush appointment unless you say otherwise. Thanks for peaking my interest.
Zu Audio Union 6 Supreme
I thought I would post my experiences listening to a new pair of Zu Union 6 Supreme in my home system. I wouldn’t call this a review. As of today, I’ve had these speakers in my home for a little over two weeks and they are still changing.
I have a “main” system consisting of a Kuzma Stabi R table, Pass labs phono and pre feeding a Vandersteen HPA-5/Vandersteen Quatro Wood speakers. My ears are used to the amazing imaging, full range, mid-hall perspective that this system delivers. The living room space is open but untreated and acoustically challenging. This is the system I have documented on Audiogon.
In a second basement system, where acoustics are much better for a more first row presentation, I have been enjoying a system consisting of a Lyra Etna SL on a Kuzma Stabi arm feeding a Sutherland mini loci pre or a Bel Canto E1X streamer/DAC as front end. These signals go to a Decware Torii MK IV and a pair of Lii Audio Fast 15 mounted into nice wooden cabinets with a front port. This presentation works best when augmented by a pair of subwoofers as the Lii drivers don’t output much below 50hz. What I love about this combo was the amazing clarity of the Decware-> Lii crossoverless combo. It is holographic an immersive and fun. All the clichés about hearing new things in the recording and meaningful music information apply here. The high frequency extension isn’t there but not missing enough to sound dull, complex music can get a little congested but not distractingly so. The drivers in this speaker cabinet can have a boxy sound in the upper bas region that was improved with additional speaker The main issue is the need for subs which eliminates the ability to go direct from phonostage to the Decware as my current subs require a home theater processing (that the Bel Canto can do). The sound of the phono digitized through the Bel Canto isn’t as nice as the clarity of the direct all analog connection.
Fast forward to Apona last year where I got a chance to hang out in the Zu Audio/Kimber cable room. Here, a cable switching system had ben set up with duplicate Pass XA25 amps and Zu DWX to demonstrate differences between different “kable” looms. I had a chance to talk with Sean Casey of Zu and was able to get a morning demo of the pair of Union 6 speakers without all the cable switching shenanigans. This demo peaked my interest in the Zu approach of high efficiency, crossoverless design. I liked the clarity, big soundstage, excellent bass integration and energy of the system. I got the feeling they would work well as a full range speaker in my current second system with the wide variety of music I like to play (similar to what Sean likes to listen to as well).
Although Sean warned that the Union 6 Supreme version of the Union 6 (Jupiter caps on the tweeter high pass and their Event internal cabling) requires a longer break in and can be ruthlessly revealing of upstream amplifier quality (I believe he described them as a “mother bitch”), I ordered a pair this October (2024). I received the pair in mid November and they are beautiful speakers. Zu had excellent communication of the process and ships these speakers in individual boxes.
I subbed out the Lii Audio custom speakers and did some basic speaker placement maneuvers to get the frequency balance and imaging optimized. The speakers are about 8 feet apart and I am sitting about 8 feet in front. They are 32 inches from the side wall and 48 inches from the front wall. The speakers are only slightly toed in. I have been playing them frequently and they are coming along nicely. Here is what I have noticed so far. They image spectacularly, they have excellent bass response without the need for sub augmentation in my system. They have a slight warmth to them that brings out color and tone of the music. Maybe the result of putting everything through a 10 inch driver? On digital recordings, I employ the subs below 80 Hz and roll off the bass to the mains below 80Hz. I prefer the all analog Lyra/Kuzma/Sutherland path for its clarity and coherence which has no subs or mains crossover. My impressions are that these speakers mate well with the Decware ~26watts of Class A push-pull and zero negative feedback. Decware amps are not warm or "tubey" sounding.
On both digital or analog paths, I am hopeful that the Union 6 Supremes will mellow out with further break in. They can sound quite forward on certain recordings which would be more pleasant if they didn’t also have a harsh edge to them. From what I've read from other Zu model reviews, this quality can be tamed with time, so I am hopeful. This forwardness necessitated a swap out of PSVANE PH EL-34s in the Decware to Tube Audio Doctor KT-66s. These KT-66 are too mellow for my tastes with the Lii Audio speakers but make 90% of the recordings sound great with the Zu Union 6 supremes. My next move may be to swap out my Etna SL with a Koetsu Rosewood Signature Platinum I have in the main system. I'll give them more weeks of play regardless.
To summarize. I made a move to Zu Audio and am excited about what I hear in a second tube based system. They have some breaking in to do but I’ll continue to post on this thread about how they are morphing. Hoping to hear from others with experience with Zu, tube amplifiers and high efficiency speakers as well.
I have been really enjoying the immersive sound of the Unions. They have tamed a bit and have maintained their imaging, detail retrieval and tone. To try them in a different context, I installed them in my main system and in a larger more lively room. The Pass Labs phono and linestage feed Vandersteen M5-HPA amplifiers. I set the amplifiers to roll off below 20 hz to send the Zu's a full frequency signal. The speakers work well in this room too. Piano, brass and saxaphones sound very realistic and lively. I think they would compete with my old Vandersteen Quatro Woods if I had dual subwoofers in this system.
I am very happy I decided to explore Zu speakers in my home. |
Listened to Jeff Parker’s excellent "The Relatives" record last night (among others) and really appreciated how these speakers present the combination of drum ket, electric guitar and upright bass. Both bowed and plucked bass sounded balanced and very natural. The distracting edge to the presentation was nowhere to be heard last night. |
Thanks Rich. I did not prefer the TAD KT-66 with the Lii Fast 15 but they tame the beast nicely with the Union 6. I can't do KT88 in my Decware but I know there are several good KT-66 choices. I'll keep an eye open for Gold Lions. I do have some Gold Lion KT-77 but I bet they will be too much while I break in the Union 6. |
@rar1. You probably know this but the Union 6 models have 8 ohm nominal impedance that is pretty flat across the listening spectrum with a rise in the lower Hz range likely related to their ZuGriewe system. I know the DW models are supposed to be very easy to match with amps and easy on the ears. I'm hoping I get there eventually and have the clarity and performance of the higher level concentric drivers too. |
Here is a nice description of burn-in break-in that goes on with these interesting drivers. https://www.zuaudio.com/theblog/loudspeakerburnin1
As a home user, I have noticed changes in the overall behavior of the speakers in the these first couple weeks of steady use. Some of this may be due to the speakers being new or the shipping that is also supposed to affect the performance. Some of it may be me getting used to the new presentation. The consistent finding is still a little edge to upper frequencies in the presence zone. Had a couple hours to listen last night to mainly electronic music and it was fantastic with the subs, (Vandersteen V2W x 2). |
Hi Karl - I have ZU speakers in my two main (most used) systems. The ZU Dirty Weekend floor standers are paired with a Prima Luna PL5 amp, Musical Fidelity CD PRE 24 preamp/ CD player, & Technics 1200 TT, Decware ZP3 phono preamp. So tube power amp/ SS preamp. Tubes are: Gold Lion KT-88 tubes; NOS GE 12AU7; Ruby 12 AX7. Awesome sounding to my ears. I have had this set-up in place with the ZUs for the last 5 years or so. The characteristic ZU sound which is dynamic is in full force. The speakers are roughly 7 or 8 feet apart and close to the wall. I have ZU OMEN Bookshelf speakers paired with a Billie Heaven 11 hybrid amp, PS Audio CD/ SACD Transport, PS Audio Gain Cell DAC, & Technics 1200 TT, use Heaven 11 phono preamp. Same overall ZU sound quality. Excellent with vocals. This system has been in place 2 or so years. Curious note: there is a mention in the Heaven 11 user guide NOT to pair with ZU speakers because of the high impedance rating of Zu speakers. I have not heard anything negative with this pairing. Good luck with your purchase, I didn't think that break-in was all that long, but that is what winter is for. Rich
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Hey @lak, thanks for commenting. I’m looking forward to the journey. I’m hopeful that they end up being an excellent tool to swap in other amplifiers and sources. |
Thanks for the post, I look forward to reading thoughts that others have, also. I own a pair of the Zu Union 6 Supreme speakers that I've had for a few years and I alternate them in and out with other speakers in a few different systems. Give your speakers some additional time to rid the harsh edge and I think you will be happy with them. |
