PSB Synchrony T600 loudspeaker

Exactly five years ago as I write these words, I reviewed an elegant-looking and elegant-sounding tower loudspeaker from Canadian manufacturer PSB: the Imagine T3. Priced at $7498/pair before it was discontinued, the T3 combined three woofers, each housed in its own vented subenclosure, with a 5.25" midrange unit mounted above a 1" tweeter.

As I write these words I am listening to a pair of PSB's new Synchrony T600 loudspeakers, which cost $7999/pair and were designed, like the T3, by a team led by PSB founder and chief acoustic designer Paul Barton. Also like the T3, the T600 houses each of its three woofers in its own vented subenclosure, married to a 5.25" midrange unit and a 1" titanium-dome tweeter, again with the midrange unit mounted above the tweeter. But there, the similarities end.

The most obvious difference is that, whereas the Imagine T3 featured a gracefully curved, veneered enclosure formed under pressure from MDF laminations, the Synchrony T600 is a conventional-looking tower with a gloss-finished, rectangular–cross-section cabinet made from MDF and an aluminum-clad front baffle. While the T3's three 7" woofers featured cones of compressed felt and fiberglass, the T600's three 6.5" woofers use cones of woven carbon fiber, allied to rubber surrounds and cast-aluminum baskets. The midrange unit's cone is also formed from woven carbon fiber, and the new drive units are said to offer low levels of distortion, due to each incorporating a Faraday ring, a shorted turn, a long voice coil, and symmetrical magnetic drive.

PSB claims that the crossover between the midrange unit and the tweeter, set at a relatively low 1.8kHz, is "the most advanced amplitude-perfect Linkwitz-Riley 4th order crossover that PSB Speakers has ever utilized, featuring high-voltage poly film capacitors and oxygen-free interconnect wire for complete driver control." The crossover frequency between the midrange unit and the woofers is specified as 450Hz, with third-order Butterworth high- and low-pass filters. However, this crossover frequency applies to the topmost woofer: As shown in the "Measurements" sidebar, the lower two woofers roll off at successively lower frequencies. Each woofer is reflex-loaded with its own back-panel port. Two rubber plugs are supplied with each speaker so that one or both ports can be sealed to compensate for problematic room acoustics. Electrical connection is via three pairs of five-way binding posts at the base of the rear panel. Jumpers are provided to allow tri- and biwiring or tri- and biamping.

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The T600 sits on two metal outrigger bases supported by custom IsoAcoustics feet based on GAIA II isolators. These feet act as low-pass filters, reducing the coupling of the loudspeaker's higher-frequency cabinet vibrations to the floor.

System and setup
Each speaker's front baffle ended up 131" from the listening position and 81" from the wall behind it, toed-in toward the listening position. The woofers of the left Synchrony T600 were 31" from the LPs that line the nearest sidewall; the right-hand speaker's woofers were 43" from the bookshelves that line its sidewall. When I sit in my listening chair, my ears are 36" from the floor, a couple of inches below the center of the Synchrony T600's midrange unit. I didn't use the magnetically attached grilles. With all three ports open on both loudspeakers, the lows sounded powerful—indeed, excessive. After some experimentation, I inserted rubber plugs into the bottom and top ports on the right-hand speaker and the left-hand speaker's top port. This yielded the smoothest transition between the low- and midbass regions.

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The music source was my Roon Nucleus+ powered by either an HDPlex linear power supply or its own switching supply. An MBL N31 CD player/DAC or an Ayre QB-9 Twenty D/A processor (footnote 1)—this kindly loaned me by reader Charles King when we met at a celebration of Art Dudley's life in July 2021—were fed audio data over my network or via USB, respectively. Amplification was provided by a pair of Parasound Halo JC 1+ monoblocks. I didn't use a preamplifier. The speakers were single-wired, first with AudioQuest K2 cables, later with AudioQuest's relatively new Robin Hood cable.

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Listening
Once the setup was optimized, I started the critical listening with the test tone files I created for the Editor's Choice CD (Stereophile STPH016-2), as I always do with my loudspeaker reviews. The dual-mono pink noise track sounded smooth with an uncolored midrange, with, however, some upper-bass emphasis. The image of the pink noise was appropriately narrow and stable with no "splashing" to the sides at any frequency. The balance didn't change appreciably as I moved my ears a little lower, but a slight vowel character was apparent if I sat up so that my ears were just above the top of the speakers.

The Synchrony T600s reproduced the 1/3-octave warble tones on Editor's Choice down to 40Hz with the 160Hz warble a little too high in level and the 100Hz and 80Hz warbles slightly lower in level than adjacent warble tones. The 32Hz tone was reinforced by the lowest room mode, the 25Hz warble was still audible at my usual listening level, but I couldn't hear the 20Hz tone. The warble tones sounded clean, which implies low distortion.

The half-step–spaced tonebursts on Editor's Choice spoke cleanly and evenly down to 32Hz, the frequency of the lowest one. Listening to the enclosure with a stethoscope while these tonebursts played, I could hear very little liveliness on the sidewalls. Some midrange resonances were audible with the stethoscope on the back panel, but the fact that this panel faces away from the listener should reduce the audibility of any resulting coloration.

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Test signals done with, it was time for music. I have always loved Brahms's two piano concertos, not only for their heroic scale but also because of their richly melodic scoring. A recent discovery, courtesy of Roon and Qobuz, was Lars Vogt's performances of these concertos with the UK's Royal Northern Sinfonia, Vogt leading the orchestra from the piano (24/48 FLAC, Qobuz/Ondine). The second concerto sounded rich and warm on the PSBs, and the double basses and the piano's left-hand register were reproduced with appropriate weight. The sound of the piano had excellent leading-edge definition, and the Synchrony T600s were sufficiently transparent that I was able to hear the hall's reverberant signature in this rather dry, flat-perspectived recording, so that I could sit back and enjoy Vogt's perhaps overly dramatic interpretation.


Footnote 1: Stereophile hasn't reviewed the QB-9 Twenty but we did review Ayre's original QB-9 in October 2009.
COMPANY INFO
PSB Speakers International
633 Granite Ct.
Pickering, Ontario L1W 3K1
Canada
(905) 831-6555
ARTICLE CONTENTS

COMMENTS
TomS's picture

JA, no preamp, really? where was volume control happening? I would think your listening notes might be different if there was an active preamp in the chain. which brings me to the second point, the treble response of these speakers seems to be deliberately shelved down above 10khz, though with a large peak over 20khz. You commented at length about getting the bass right, but you said little about treble detail in the listening section (except to note the Cantons sounded more detailed). Is the fact the the crossover to the treble is relatively low (1.8khz) somehow related to the fact that the FR is so tipped 'down'? Again, I would have thought that using an active preamp in the chain (the parasounds are presumably designed to be used with a preamp) would have changed the total sonic signature. Of course, I am well aware that a truly transparent active preamp is hard to find and expensive. Etc.

John Atkinson's picture
TomS wrote:
JA, no preamp, really? where was volume control happening?

I controlled volume with Roon.

TomS wrote:
I am well aware that a truly transparent active preamp is hard to find and expensive.

Yes indeed. The excellent but expensive MBL, Audio Research, and Pass Labs preamps I have used in the last year or so have all gone back to the manufacturer or to other reviewers.

John Atkinson
Technical Editor, Stereophile

Duck851's picture
Quote:

I controlled volume with Roon.

Digitally, or "analogly" ?

John Atkinson's picture
Duck851 wrote:
Digitally, or "analogly" ?

Control in the digital domain.

John Atkinson
Technical Editor, Stereophile

Ortofan's picture

... is "the widest-bandwidth, widest-dynamic-range, lowest-noise, lowest-distortion preamplifier I have encountered."

According to KR, the Benchmark LA4 preamp is "probably the most transparent and revealing audio component I've ever used. It does not seem to leave any fingerprints on the sound."

The price of the Benchmark LA4 preamp is (only) $2,499.

https://www.stereophile.com/content/benchmark-la4-line-preamplifier

JRT's picture

Benchmark also offers their HPA4, which includes a very good headphone amplifier, but is otherwise similar to the LA4 preamplifier that you mentioned.

These seem to be a good choice for use with a pair of loudspeakers using conventional passive crossovers, and include an additional summed mono output which might be useful for connecting a subwoofer system, but without any facility to reshape the satellites' high pass response for better integration with a separate subwoofer system.

Sadly, while either of those preamplifiers might be a good choice for use with a pair of conventional loudspeakers with passive crossovers, these are not very useful with more advanced systems using DSP active crossovers in multi-way loudspeakers, or in other playback setups requiring use of more than two channels of audio, because they lack any facility for slaving more channels to the one master volume control.

Kal Rubinson's picture

Sadly, while either of those preamplifiers might be a good choice for use with a pair of conventional loudspeakers with passive crossovers, these are not very useful with more advanced systems using DSP active crossovers in multi-way loudspeakers, or in other playback setups requiring use of more than two channels of audio, because they lack any facility for slaving more channels to the one master volume control.

See:
https://www.stereophile.com/content/benchmark-la4-line-preamplifier-multichannel-application

https://www.audiosciencereview.com/forum/index.php?attachments/la4x3small-jpg.55706/

JRT's picture

Yours was a creative solution. Thank you for posting that.

John Atkinson's picture
Ortofan wrote:
According to KR, the Benchmark LA4 preamp is "probably the most transparent and revealing audio component I've ever used. It does not seem to leave any fingerprints on the sound."

I did write about the sound of the Benchmark LA4, along with that of the MBL N11, in my review of the Pass Labs XP-32: www.stereophile.com/content/pass-laboratories-xp-32-line-preamplifier-page-2.

John Atkinson
Technical Editor, Stereophile

Ortofan's picture

... "a truly transparent active preamp is ... expensive".
The Benchmark was intended to be an example of a truly transparent active preamp that was not particularly expensive.

One would then have to audition the preamp to see if it does indeed offer improved sound quality over no preamp at all.

Also, if you already had these ($8K) speakers as part of a preamp-less system, and have about $17K (which is the price of the Pass XP-32) in the budget for a system upgrade, would you be likely spend that entire sum on a preamp, or might a greater improvement be realized by spending part of it on a preamp and the balance on upgrades to other system components?

Jonti's picture

...for "Student Demonstration Time"! Surf's Up is a near-perfect album without that track. I always have to remind myself to lift the tonearm as soon as "Disney Girls" (the penultimate track on side one) ends.

Incidentally, do you approve of the modern remasters of Surf's Up? I've never heard a version anywhere near as lush as the original vinyl pressing.

Oh and on the subject of the extraordinary closer, the title track, I would urge you to search out David Thomas & Two Pale Boys' fascinating elongated reinterpretation from 2001. It's on their album of the same name. Not so much a cover as an homage. Enjoy!

dcolak's picture

Are we looking at the same graphs? There is nothing excellent in that frequency response. Twitter dropping like a stone at 15Khz? Uneven all over the place? What's excellent?

Axiom05's picture

But at least the tweeter response goes higher in frequency than the Magico M2's. Haha

What I find interesting is that for the longest time designers tried to push the tweeter resonance higher and higher in frequency, getting further away from the audio band. However, recent trends seem to be the use of tweeters that have their resonance just about 20KHz resulting in "poor" performance in the last octave.

John Atkinson's picture
dcolak wrote:
Are we looking at the same graphs? There is nothing excellent in that frequency response. [Tweeter[ dropping like a stone at 15Khz? Uneven all over the place?

It appears that you are looking different graphs. Mine show that the T600's farfield output is impressively even from the midrange through to 15kHz, with small dips balanced by equally small peaks. (The ear is insensitive to this behavior, as long as the departures from flat are small.)

The drop in the tweeter's output above 15kHz is, I believe, relatively inconsequential given the ear's relative insensitivity to energy in this region, even for those with hearing that extends above 15kHz.

John Atkinson
Technical Editor, Stereophile

krahbeknudsen's picture

I often wonder how such a sharp upper resonance/ringing of a metal dome tweeter affects the rest of the response. I would be interesting to excite the peak while measuring response and distortion in the rest of the tweeter's spectrum if that is possible? Think a NOS dac throwing an alias of a cymbal up there for instance.

tonykaz's picture

Dear John,

I wonder if a proper piece on living without a PreAmp would be helpful to we readership at large ?

I would love to read the opinions of our Leading Authorities ( like you and even Mr.HR ) on this significant concept.

I've been without a Pre for some time now while feeling rather liberated.

Your clarity is refreshing.

Tony in Florida

Jazzlistener's picture

…is a real let-down. Could you have been any less enthusiastic? Were you late for an appointment?

TomS's picture

I found some discussion on the Roon user's group about where the digital volume control occurs in the signal chain inside the unit (as DSP?); I am actually somewhat surprised that JA considers this a better solution all around, especially if one is losing resolution by attenuating in the digital domain. Correct me if I'm wrong but I read the earlier review of the Roon and there's no analong volume control there. Be that as it may, there are advantages and disadvantages as always. Still think using an active preamp might benefit the overall result with a speaker that is somewhat reticent in the treble.

Kal Rubinson's picture

"I am actually somewhat surprised that JA considers this a better solution all around, especially if one is losing resolution by attenuating in the digital domain."
It depends on how it is done. The better ones work at 64bit resolution.

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