DALI Callisto 6 C wireless loudspeaker Page 2

Two 30W class-D amplifiers drive the tweeter module and the woofers. DALI says these amplifiers are rated for 10 times the peak-to-average power required in normal use and can deliver 250W for up to 5 seconds. The crossover is implemented in the digital domain, and volume control takes place just before the speaker's Burr-Brown PCM1796 balanced-output DACs to maintain 24-bit resolution.

Callisto 6 Cs are assembled in Denmark with a Danish cabinet and components manufactured in the DALI factory in Ningbo, China.

Setup
Once the Sound Hub and Callistos are powered up, connecting each speaker to the Hub is a simple matter of first pressing the button at the top of the Hub's rear panel then pressing the connect button at the base of the speaker's rear surface, above the inset connection panel. (A display next to the speaker's button allows you to choose whether the speaker is the left or the right.) Each speaker emits a reassuring low-pitched chime when the connection to the Sound Hub is confirmed. The Sound Hub's analog and digital inputs can then be used, the Hub automatically switching to whichever source is connected (other than the 3.5mm jack). For this review, I connected the Sound Hub to my network and activated it as a Zone in the Roon 1.6 app running on my iPad Mini.

819dali.roon

I started my listening with the DALI speakers in the positions where the Joseph Perspective2 Graphenes had worked well when I reviewed them for the July 2019 Stereophile. The woofers of both were 75" from the wall behind; those of the left speaker were 30" from the LPs that line its sidewall; the right speaker's woofers were 45" from the books that line its sidewall. (A small raised platform at the front right of my room mandates the asymmetrical placement.) The Callistos produced a superbly even bass balance in these positions, so I left them there.

The speakers were initially toed-in to the listening position, but in that orientation I found the high frequencies excessive. I then tried the speakers firing straight ahead, as recommended by DALI, but ended up with a slight, 5° toe-in, which gave the smoothest mid-treble balance. A fairly bulky, cloth-covered plastic grille plugs into the upper section of the Callisto 6 C's front baffle; I left the grilles off for my auditioning.

Sound quality
DALI says in their user manual that the Callisto 6 C will take about 100 hours to break in. I therefore used the speakers for a couple of weeks before I started my serious auditioning. At first, I used the Callistos with their analog inputs connected to the single-ended outputs of my PS Audio DirectStream D/A converter.

Listening to the dual-mono pink noise track on my Editor's Choice CD (Stereophile STPH016-2), the Callistos produced a stable, narrow central image, though with some of what the late J. Gordon Holt used to call "vertical venetian blinding" as I moved my head a few inches from side to side. (This is due to narrow-band cancellations in the treble between the sounds from the two speakers.) The image of the noise wasn't quite as narrow as that offered by the KEF LS50s, which I confirmed by listening to Nathan Milstein's 1951 performance of Dvorák's Violin Concerto in A minor (Op.53) with Antal Doráti conducting the Minneapolis Symphony Orchestra (16/44.1 AIFF file, Naxos 8110975). The violin was recorded too loud in relation to the orchestra, but its image was stable, ie, didn't wander with frequency. And I was surprised at the amount of image depth apparent on this mono recording, the horns, for example, sounding a long way behind the soloist.

The pink noise track sounded a little top-heavy if I sat up straight so that my ears were just above the ribbon supertweeter, which is 37" from the floor. With my ears level with the ribbon unit, the balance was more even, though still with perhaps a touch too much top-octave energy.

819dali.mid

At the other end of the spectrum, low frequencies sounded powerful. The 1/3-octave bass warble tones on Editor's Choice were produced with good weight down to the 40Hz band, with then the 32Hz warble tone exaggerated by the lowest mode in my room. At my typical listening level, the 25Hz band was just audible but the 20Hz band was missing in action. Commendably, there was no audible wind noise or "chuffing" from the ports with the lowest-frequency tones. Overall, the warble tones sounded extremely clean, with no audible distortion. The half-step–spaced tonebursts on Editor's Choice spoke clearly and evenly down to their 32Hz lower limit, but with a slight emphasis to the leading edges of the tonebursts.

I doubt that the Callisto 6 Cs will be used without their companion Sound Hub; all my subsequent auditioning was therefore performed with the Hub sending data wirelessly to the speakers. Like the Callisto speaker, the Sound Hub digitizes its single-ended analog inputs. To examine how an analog signal fed to the Sound Hub's analog inputs compared with the original digital data, I sent the same data to the Hub's BluOS module and to the PS Audio DAC via Roon over my network. Playing the 1kHz warble tone from Editor's Choice and with the DirectStream's volume set to its maximum, I had to increase the Sound Hub's volume control by three "clicks" to give an spl within 0.5dB of that with the digital connection.

With this housework done, the dotted rhythm of the opening "Komm, ihr Töchter, helft mir klagen" from Bach's St. Matthew Passion, with John Butt directing the Dunedin Consort (24/88.2 Studio Master download, Linn CKD 313P), sounded equally compelling from both sources. The soundstaging on this excellent recording, however, was wider and deeper with the direct connection to the Sound Hub. The soloists sounded a little shut-in with the analog connection from the PS Audio DAC. Repeating this comparison using my Ayre disc player as a source, sending AES/EBU CD data first to an antique Digital Domain VSP format converter to convert it to S/PDIF, then sending the data simultaneously to both the PS Audio DAC and the Sound Hub, gave a similar result. The drums and cymbals on "Maybe You'll Be There" from Diana Krall's Live in Paris (CD, Verve 065 109-2) were set farther back in the soundstage with the direct S/PDIF feed. The image of Krall's voice on her hauntingly beautiful treatment of Joni Mitchell's "A Case of You" was more palpable with the digital connection to the Hub.

819dali.woof

The Sound Hub's analog inputs are useful, but the digital inputs get the best from the Callistos for serious listening. I continued my auditioning using Roon to send digital data to the Sound Hub via my network. I downloaded and installed the BluOS app on my iPad Mini, but as this integrates the Roon functionality, including controlling the Sound Hub's volume, I stuck with the familiar Roon interface. (Perhaps I am too easily amused, but I did find it intriguing that when I was running Roon on my laptop while the BluOS app ran on my iPad, adjustments to the Callisto system's volume level via the laptop slider were reflected in changes in the Sound Hub's numeric display, by the bargraphs on the fronts of both speakers, and by the volume control in the BluOS app.)

For this ex-pat, Vaughan Williams' The Lark Ascending always conjures a vision of the English countryside. My favorite performance is from violinist Nigel Kennedy, with Simon Rattle conducting the City of Birmingham Symphony Orchestra (16/44.1 ALAC file, from EMI Classics 72435 56413 2 8). The works starts with hushed strings murmuring behind the soloist as he moves up the fingerboard of his instrument, the lark into the air. The Callistos sent shivers down my spine with this recording. The image of Kennedy's violin moved slightly from side to side, but I suspect this is an artifact of the miking, as the image of Milstein's instrument in the Dvorák concerto was stable with frequency. Rosin noise from Kennedy's bow was a little more audible than I am used to, but not to the extent that it distracted from the music making. The woodwinds were set well back in the soundstage, the orchestral image wide and stable.

The Callisto's midrange was natural-sounding. After the Vaughan Williams, Roon Radio selected a track I hadn't played for a long time, Hyperion Knight performing Earl Wild's arrangement for piano of the Grand Fantasy on Porgy and Bess, from Rhapsody (16/44.1 ALAC file, Stereophile STPH010-2, footnote 1). The 9' Steinway D nicely illuminated the acoustic of Albuquerque's First United Methodist Church, where I had made the recording in 1997. The sound of the piano and its image via the DALIs was true to my memories of the sessions, and the instrument's lowest notes were played back with an excellent combination of weight and articulation.

819dali.spkr2

I suspect that the claims made for the low distortion of Callisto's woofers are correct: My Fender bass guitar on the channel identification tracks on Editor's Choice had superb weight and articulation. The deep if overcooked bass notes that underpin "Cast Off" on Bruce Hornsby's relatively new Absolute Zero (16/44.1 ALAC file, Zappo Productions Zappo001) were reproduced with impressive heft but without undercontrolled boom.

A recent purchase and a contender for Stereophile's 2020 "Records 2 Die 4" is the complete set of Beethoven Symphonies with Simon Rattle conducting the Berlin Philharmonic (24/192 WAV files, Berliner Philharmoniker BPHR 160091). The soundstage on Symphony 7 was reproduced with good depth. The double-bass notes that punctuate this symphony's second movement, Allegretto, were both superbly well articulated and reproduced with good weight.

819dali.tweet

Downsampling
What about the fact that even though the Sound Hub will accept PCM data sampled at 192kHz, it downsamples the rate to 96kHz before transmitting them to the Callistos? A favorite test track for assessing transparency is "Die Tänzerin" from German singer Ulla Meinecke's Wenn Schon Nicht für Immer, dann Wenigstens für Ewig (24/192 needledrop made with the Ayre QA-9 A/D converter from LP, German RCA 426124). Though Meinecke is balanced relatively upfront in the mix, the recording has tremendous dynamic range, and both the voice and the stereo keyboard are accompanied by generous helpings of reverberation and repeat echo. Playing this track, I literally count how many echoes I can hear before they are obscured. Some systems dry out the reverb to a noticeable degree, but the Callistos did well, lighting up a deep dome of artificial ambience at the appropriate times. The dry-sounding finger snaps on "Die Tänzerin" were pushed a little more forward in the soundstage than I am used to, but not to the extent that it mattered. And the differences between the Ayre QA-9 and the Benchmark A/D converter with which I had made an alternative needle drop were well-resolved.

The Callisto's necessary downsampling of high–sample-rate data would therefore seem to be reasonably benign.

Conclusion
I found that the treble balance requires some care with setup in the owner's room, but when that is optimized, at $5750 with the Sound Hub and BluOS network module, DALI's Callisto 6 C system is competitively priced when you take into consideration its fit'n'forget nature and its excellent sound quality. I enjoyed my time with this system. You will too. It is the very model of a self-contained music reproduction system.


Footnote 1: The booklet notes for this CD feature some of the best writing Wes Phillips, who died on August 27, 2016, contributed to Stereophile.
COMPANY INFO
DALI A/S
US distributor: NAD Electronics International
633 Granite Court
Pickering, Ontario L1W 3K1, Canada
(905) 831-6555
ARTICLE CONTENTS

COMMENTS
Kal Rubinson's picture
Quote:

Although the midrange balance is even, there is then a lack of energy between 1kHz and 3kHz, above which the region covered by the two tweeters is 3–5dB too high in level. This behavior is not dissimilar to that of DALI's Rubicon 8; as with that speaker, it is why DALI recommends firing the Callistos straight ahead rather than toeing them in to the listening position.

Again, one has to wonder why they do this. What is the upside?

Ortofan's picture

… any speaker designer as to why they might choose to adopt less than the flattest possible/most neutral frequency response for their products?

A notable contrast is the passive speakers from KEF vs. B&W.
While the latest KEF products are typically quite uniform overall, contemporary B&W models generally exhibit significant deviations from flat frequency response. Yet, B&W seems to be a popular choice for monitor speakers among recording studios.

AJ's picture
Quote:

Has there been an explanation from any speaker designer as to why they might choose to adopt less than the flattest possible/most neutral frequency response for their products?

I/they could tell you, but then would have to kill you.
So best kept secret/proprietary.

AJ Soundfield Audio

Bogolu Haranath's picture

Are you referring to B&W 805 D3? ........ 805 D3 frequency response somewhat looks like the Fletcher-Munson curve ....... B&W top of the line 802 D3 frequency response looks 'reasonably' flat ......... Most of the recording studios usually choose top of the line models of any loudspeakers from any manufacturer :-) ........

Ortofan's picture

... here:
https://www.hifinews.com/content/bw-702-s2-loudspeakers-lab-report
https://www.hifinews.com/content/bw-603-loudspeaker-lab-report
https://www.hifinews.com/content/bw-805-d3-loudspeaker-lab-report

Bogolu Haranath's picture

B&W 700 and 600 series are not their top 'reference quality' models. I don't think recording studios would use them for monitoring ......... B&W 805 D3 was also reviewed by Stereophile ........ I mentioned that ........ 805 D3 is a bookshelf model ........ Most of the recording studios use powered monitors for initial monitoring over the recording consoles ......... Most of the B&W speakers used by the recording studios for their final mixing and monitoring are B&W top models, 800 D3 or 802 D3 :-) .........

Bogolu Haranath's picture

BTW .... The frequency response 'roller-coaster' ride of the B&W 603 looks worse than the Wilson Audio TuneTot, also reviewed by Hi-Fi News :-) .........

B&W 603 is EISA award winner ........ Were they drinking 'Kool-Aid'? :-) ...........

Bogolu Haranath's picture

Even the B&W 702 S2 frequency response looks almost similar to the 'roller-coaster' ride of B&W 603 ...... May be that is the 'secret sauce'? :-) .........

Bogolu Haranath's picture

Even the 'diamond tweeter' used in their top models 800 series, shows similar type of frequency response as 700 and 600 series ...... although, to a lesser extent :-) .........

Bogolu Haranath's picture

Like JA1 said, 'idiosyncratic' indeed :-) .........

ralphgonz's picture

@Ortofan, having spoken with a few recording engineers, I think many (consciously or unconsciously) prefer an elevated treble response since it helps them hear unwanted noise, artifacts, mouth noise, and mechanical clicks etc that need to be edited out. Many are older males who have some degree of high frequency hearing loss as well.

While this should translate into dull-sounding mixes when played back on flat speakers, I think the engineer knows to compensate -- and otherwise the mastering engineer will restore the appropriate balance as a final step.

It should also be noted that most studios have 2 or more different sets of playback monitors. One might be more "analytical" (elevated highs) while another may be more flat for long-term listening without ear fatigue.

Ortofan's picture

... most neutral monitoring speakers through which to hear the finished product.
If an elevated high frequency response is useful during the editing process, then that could be achieved with an equalizer. Likewise, if the recording engineer is afflicted with some degree of frequency-dependent hearing loss, then, with an audiogram from a hearing test in hand, the response of the monitors can be adjusted to compensate.

ralphgonz's picture

Per-person EQ makes sense, though I would think it is uncommon in a recording environment, partly because it adds a source for potential errors: applying the wrong person's EQ, applying the EQ to the wrong monitors, basing the EQ on an inaccurate audiogram, leaving the EQ active for the next engineer, etc.

The engineer is well aware of his/her own hearing limitations and is usually familiar with the "sound" of specific monitors from having heard many reference tracks over them. Therefore they are able to compensate by aiming for the same "sound" in a new recording.

I'm not a recording professional (though I've done a fair amount of amateur recording/engineering), just trying to suggest why studio monitors, even the classic BBC LS3/5a, sometimes have elevated on-axis treble.

Incidentally I once wrote a plugin for recording software which let you simulate the EQ of several common speaker types while listening over headphones. The purpose was to help assess how a mix might sound in common less-than-perfect environments. I'm not sure if it ever got any use, and it is unfortunately stuck in 32 bit Windows territory... https://sites.google.com/site/ralphgonz/music-vst

Bogolu Haranath's picture

@ralphgonz ...... Why would not any recording engineer check for all the settings, before he/she starts recording/monitoring? ........ especially, if another different engineer used the equipment before? :-) ........

Bogolu Haranath's picture

Also, as you may already know, most of the active monitors used by the recording studios these days come with built-in user adjustable EQ/tone controls ....... Some active monitors can even do advanced DSP and come with calibration microphones and software programs :-) .........

Bogolu Haranath's picture

In addition to all of the above, lot of recording engineers use headphones for monitoring ........ JA1 was using headphones for monitoring for his recordings in the 90's :-) .........

JHL's picture

Approximately: Because speakers aren't linear devices.

The biggest downfall of the amplitude response war - and there are many - is that it carried with it an assumption that speakers are linear, even nearly digital devices. Get the static response right on paper and it's perfected.

Speakers just don't work that way.

Ortofan's picture

... speakers work?

JHL's picture

...that isn't rhetorical, bear in mind that gallons of ink have been spilled on the subject; it's not going to be re-litigated in the comments section of the online edition of a hifi publication, is it?

A question instead: How many characteristics does a loudspeaker have? Because somewhere in that mix lies the ironclad realization that speakers aren't lines on a chart of level versus frequency.

Ortofan's picture

... lines on a chart of level versus frequency, then, supposing you are in charge of producing such speakers, how do you perform quality control on outgoing products?

JHL's picture

No differently.

Ortofan's picture

... from what?

Bogolu Haranath's picture

"I take your question" :-) .........

Bogolu Haranath's picture

..... Or, that is way, way beyond the 'purview' of those darn objectivists :-) .........

Bogolu Haranath's picture

Just employ a few 'Golden Ears' in the quality control department, who are graduates of 'Golden Ear' university :-) ........

Bogolu Haranath's picture

Does this non-linearity you are describing, applies to both passive and active speakers? ........ By active speakers meaning, self powered speakers with multiple amplifiers connected directly to the transducers and an active crossover placed before the amplifiers? ...... Also, does this non-linearity applies to all types of speakers including dynamic, planar magnetic and electrostatic speakers? ....... Not to mention, speakers like MBL? ........ Could you elaborate about this non-linearity? :-) .........

AJ's picture
Quote:

The biggest downfall of the amplitude response war - and there are many - is that it carried with it an assumption that speakers are linear, even nearly digital devices.

That is a projection, not an assumption.
33 yrs ago, with references dating back to the 1930s
http://www.aes.org/e-lib/browse.cfm?elib=5251

AJ Soundfield Audio

ralphgonz's picture

To Kal Rubinson's post: I'm not sure what Dali's thinking is, but personally I prefer the aesthetics of speakers firing straight ahead.

Secondly, if the treble is optimized for off-axis listening then there is a bigger sweet spot so multiple people can hear the optimum treble balance. Likewise a single listener doesn't have to be anchored midway between the speakers as they would when the optimum balance requires toe-in.

Thirdly, this enables more high frequency energy in the room reverberant response, where there is normally a deficit due to narrowing directivity at high frequencies.

Kal Rubinson's picture

To Kal Rubinson's post: I'm not sure what Dali's thinking is, but personally I prefer the aesthetics of speakers firing straight ahead.

I agree with you about this.

Secondly, if the treble is optimized for off-axis listening then there is a bigger sweet spot so multiple people can hear the optimum treble balance. Likewise a single listener doesn't have to be anchored midway between the speakers as they would when the optimum balance requires toe-in.

Is it optimized for off-axis listening or is the toe-in necessary to avoid the glare of the bumpy on-axis response? I do not know of any evidence that the size of the optimum listening position is increased under such an approach.

Thirdly, this enables more high frequency energy in the room reverberant response, where there is normally a deficit due to narrowing directivity at high frequencies.

I am not a fan of splashing excess HF energy off the sidewalls. I'd rather the bass-mid-treble balance of the on-axis response was maintained in the reverberant field by narrowing the dispersion below the treble as one sees with the BeoLab90, Kii Three and D&D 8c speakers.

AJ's picture
Quote:

Secondly, if the treble is optimized for off-axis listening then there is a bigger sweet spot so multiple people can hear the optimum treble balance.

No. Elevating the on axis (straight ahead) treble so that the 30 degree off axis or so, becomes approximately "flat" as being questioned here, does no such thing.
The only way to tailor the polar pattern for a wide(r) *stereo sweet spot has been long known to (audio) science adherents:

http://www.linkwitzlab.com/Links/Optimized-listening-area-Davies.pdf

It most certainly doesn't involve boosting the on axis treble.

cheers

AJ Soundfield Audio

Bogolu Haranath's picture

The DALI Callisto 6-C frequency response may work well for older people with high frequency hearing loss ....... Not all 'old' people have high frequency hearing loss :-) ........

ralphgonz's picture

I think we're talking about different things @AJ. By "sweet spot" I meant in terms of frequency response, not in terms of stereo image localization (the link you gave refers to using multidriver arrays to improve stereo image stability when the listener is not on the center line between the two speakers. Though the technique also increases the frequency balance off-axis, it is an expensive approach and probably not commercially viable).

If we define the horizontal "sweet spot" as the range of listening positions where treble balance is within -- say -- plus or minus 2dB of flat response, then by designing the speaker to be flat at 10 or 15 degrees off axis you will have a much wider sweet spot than one which is flat at 0 degrees.

Moreover this gives the listener the flexibility to adjust the treble balance both up and down by adjusting toe-in, whereas you can only adjust the treble balance downward if the speaker is flat at 0 degrees.

AJ's picture
Quote:

I think we're talking about different things @AJ. By "sweet spot" I meant in terms of frequency response, not in terms of stereo image localization

Then you are making up definitions. "Sweet spot" is a commonly understood term of stereophony. Heck, it can be found on Wikipedia:
https://en.wikipedia.org/wiki/Sweet_spot_(acoustics)

Quote:

The sweet spot is a term used by audiophiles and recording engineers to describe the focal point between two speakers, where an individual is fully capable of hearing the stereo audio mix the way it was intended to be heard by the mixer. The sweet spot is the location which creates an equilateral triangle together with the stereo loudspeakers...listener can enjoy the sound experience as intended by the audio engineer, including the desired phantom source locations, spectral and spatial balance and degree of immersion.

Unless the speaker has a polar pattern similar to the linked Davis paper, the image simply collapses to the nearest speaker (precedence effect) when moving laterally off axis...regardless of FR smoothness.

Quote:

If we define the horizontal "sweet spot" as the range of listening positions where treble balance is within -- say -- plus or minus 2dB of flat response, then by designing the speaker to be flat at 10 or 15 degrees off axis you will have a much wider sweet spot than one which is flat at 0 degrees.

I'm sorry, but this makes no sense. If it is "flat" only at 10-15 off axis, but elevated (on) or depressed (off) elsewhere, that makes for a very narrow - by your definition "sweet spot", not "wider". How would forcing one to be within a very narrow angle (10-15) make a listening area "wider"?

Quote:

the link you gave refers to using multidriver arrays to improve stereo image stability when the listener is not on the center line between the two speakers. Though the technique also increases the frequency balance off-axis, it is an expensive approach and probably not commercially viable

No, it requires neither arrays (to acheive the required polars) nor prohibitive expense (unless targeting only audiophiles).

cheers,

AJ Soundfield Audio

ralphgonz's picture

The discussion started by Kal Rubinson was about why speaker manufacturers sometimes design speakers to have an elevated on-axis treble region, sounding their best off axis (IE with little or no toe-in). Here is a more detailed example illustrating this.

Suppose your tweeter's response at 10kHz falls to -2dB at 10 degrees off axis relative to its on-axis response, and -4dB at 20 degrees off axis. If you set the tweeter level to be flat relative to the other driver(s) on axis, then the system's treble balance will be within 2dB of the bass and midrange from a lateral angle of -10 degrees to +10 degrees (up to 10kHz). At listening angles greater than 10 degrees the system treble balance will be excessively depressed.

Suppose instead the tweeter level is set to +2dB relative to the remaining driver(s) on axis. Now at 10 degrees off axis the system level at 10kHz is 0dB, and at 20 degrees off axis the system level at 10kHz is -2dB relative to the remaining driver(s). So within plus or minus 2dB tolerances this system will sound well balanced over the lateral range from -20 degrees to +20 degrees, twice as wide a listening angle as the system with flat on-axis response.

AJ's picture

Well, I realize this is all your speculation rather than the manufacturers actual explanation, but I'll play along.
So, according to your theory, with these elevated (treble) on axis speakers pointed straight ahead, sitting in the midpoint seat/30 off speaker on axis or say slightly off middle/20 off speaker axis, the perceived/audible spectral balance remains relatively flat/balanced, thus "wider sweet spot"?

Bogolu Haranath's picture

The two tweeters used for the high frequency are not similar, in the Callisto 6-C ....... The lower tweeter is a dome and the upper tweeter is a ribbon ........ The crossover frequency in the treble region was mentioned as 2.6 KHz in the manufacturer's specs, which is where presumably the midrange(s) are crossed over with the dome tweeter .......... We don't know where the dome and the ribbon are crossed over ....... This may have some thing to do with the perceived tonal balance, on-axis as well as off-axis ....... Also, JA1's in-room frequency response of the Callisto 6-C in the listening position is, very close to Joseph Audio Perspective2, which has only one dome tweeter :-) .........

Bogolu Haranath's picture

It is also possible, both the dome and the ribbon tweeters are crossed over at 2.6 KHz ........ Both tweeters may be working simultaneously above 2.6 KHz :-) .........

Bogolu Haranath's picture

We may need the help of Inspector Clouseau to solve this mysterious engineering of DALI Callisto 6-C :-) ........

Bogolu Haranath's picture

Two of the Sony SS-NA2ES and SS-NA5ES speakers use 3 dome tweeters of different diameters, and were reviewed by Stereophile ........ NA5ES shows almost +5 db elevated frequency response above 6 KHz in the treble region ........ NA2ES shows a dip in the low treble and not any significant elevated frequency response in the high treble :-) ...........

Bogolu Haranath's picture

May be you could send your Soundfield Audio CTA1 active speakers for a review by Stereophile? ....... They sound good in the video posted on-line :-) .........

Kal Rubinson's picture

The discussion ............... was about why speaker manufacturers sometimes design speakers to have an elevated on-axis treble region, sounding their best off axis (IE with little or no toe-in).


No, that is not what I was asking. I was responding to JA's comment that "Although the midrange balance is even, there is then a lack of energy between 1kHz and 3kHz, above which the region covered by the two tweeters is 3–5dB too high in level." In other words, why is the response so uneven with a notable cutout in the 1-3kHz range (relative both to the lower and higher ranges) as well as why the upper range is so elevated?

Suppose your tweeter's response at 10kHz falls to -2dB at 10 degrees off axis relative to its on-axis response, and -4dB at 20 degrees off axis. If you set the tweeter level to be flat relative to the other driver(s) on axis, then the system's treble balance will be within 2dB of the bass and midrange from a lateral angle of -10 degrees to +10 degrees (up to 10kHz).

Suppose instead the tweeter level is set to +2dB relative to the remaining driver(s) on axis. Now at 10 degrees off axis the system level at 10kHz is 0dB, and at 20 degrees off axis the system level at 10kHz is -2dB relative to the remaining driver(s). So within plus or minus 2dB tolerances this system will sound well balanced over the lateral range from -20 degrees to +20 degrees, twice as wide a listening angle as the system with flat on-axis response.

However, if you look at either the horizontal plane off-axis responses, there is no significant difference in the FR until almost 20kHz at up to 30deg off-axis. In other words, if this is range of reasonable toe-in adjustment it is not accomplishing either described outcome as those traces mimic the on-axis trace until well beyond 10kHz.

Bogolu Haranath's picture

The frequency response dip which starts from approx. 800 Hz and extends to approx. 3 KHz looks like the famous 'BBC dip' ........ Dali could have included some kind of digital EQ to tame that 'hot' mid and upper treble ....... Recently reviewed D&D active DSP speakers includes digital EQ in their design :-) .........

Bogolu Haranath's picture

If, they do Harman 'Spinorama' graphs, the frequency response of the DALI Callisto 6-C may almost look like the Fletcher-Munson curves :-) ........

Bogolu Haranath's picture

DALI Rubicon 8, which was also reviewed by Stereophile, has a frequency response which looks much more like the Fletcher-Munson curve :-) .........

Bogolu Haranath's picture

It would be interesting to see if JA1 could also review the JBL Stage A170 speakers ($500/pair) ........ Stage A170 looks almost similar to Dali Callisto 6-C and Joseph Audio Perspective2 ......... S&V magazine favorably reviewed those Stage A170, recently :-) .........

John Atkinson's picture
by Bogolu Haranath wrote:
It would be interesting to see if JA1 could also review the JBL Stage A170 speakers ($500/pair)...

Herb Reichert is reviewing the Stage 170 in the November issue of Stereophile.

John Atkinson
Technical Editor, Stereophile

Bogolu Haranath's picture

Great ... Looking forward to that review ....... It would be interesting to see if you (JA1) could get in-room frequency response measurements in your (JA1's) listening room, and compare those with the in-room frequency response measurements of Joseph Perspective2 and Dali Callisto 6-C :-) .........

Bogolu Haranath's picture

May be you (JA1) could also write another article, 'A tale of 3 speakers' ........ Of course, I'm referring to your (JA1's) previous article 'A tale of 2 speakers' :-) ..........

Bogolu Haranath's picture

Since you (JA1) have already compared the Revel performa M106 with KEF LS-50, may be you (JA1) could also review the Revel Performa M126Be, with the Beryllium tweeters ($4,000/pair), and compare those with the KEF LS-50? :-) .........

Bogolu Haranath's picture

Stereophile may be interested in reviewing the new Polk Audio Legend series, top model L-800 ($6,000/pair), with Stereo Dimensional Array (SDA-PRO) technology ........ See S&V website :-) ..........

jeffhenning's picture

Not having ever heard these speakers, I'm not going to comment on their sound.

From a value perspective, these don't seem to be very competitive.

Case in point:

• A pair of KEF LS50 wireless - $2,200 (factory refurbs are $1,900)
• Two Rythmik L12 servo subs - $1,100
• All of the associated peripherals (Pangea power cords, Mogami cables, ethernet for the speakers, Toslink for a video or pre-amp feed, Furman's best non-rack power center, SVS feet for the subs & stands and 24" stands for the LS50's)
• Grand total (worst case): $4,300

With a bit of comparative shopping, possibly, $3,800 or so.

(I installed a system similar to this in my bedroom with KEF LSX's and cheap [boy, are they!] Boston Acoustics 10" subs for $2,600.)

What you then get is fully active, DSP-corrected mains and two subs that can easily play a low B bass note (31Hz) and, given the set up done by the user, go down to 20Hz at sane volume levels with no distress. The total system power for the 6 amps used would exceed 1kW.

The two biggest downsides is that it will take a little bit more effort to install & dial in and that it will have a larger footprint, but not by much.

This system will outperform the Dali in just about every way for 3/4 the price.

You could save even more by using a nice set of passive tower speakers (Paradigm, maybe), omit the subs and get a good integrated amp that also has wireless (NAD?) and be close to on par with the Dali's. Is getting rid of two speaker cords worth the premium price for the Dali system?

I think they missed the mark with this one.

JHL's picture

"This system will outperform the Dali in just about every way for 3/4 the price."

And a Corvette* will outperform X, Y, and Z for less money. Why, just look at it. How can it not?

*insert F150 as needed.

Bogolu Haranath's picture

The new, first ever, mid-engine Corvette Stingray may indeed outperform many mega-buck sports-cars for lot less money :-) ........

tonykaz's picture

I admired and even loved the Meridian Active Loudspeakers of the 1980s.

I stocked them in my Esoteric Audio Salon.

They didn't sell.

Duds...

Of course the Pros love Actives for dam good reasons but the Audiophile Class of buyer needs to explore an endless stream of Interconnects, Amplifiers, Speaker Cables, Tip-Toes, etc.

I am an Audiophile ( Stereophile to Canadians ) because I enjoy using my Neurosis / Psychosis as justifications and rationalizations for wanting to experience all those wonderful performances that Mr.HR shares with us. ( including a Sugden that our Brand New Editor revealed )

Being an Audiophile is kinda like building & flying Experimental Aircraft.

Active Loudspeakers are more like flying First Class in a 747 .

Tony in nearly Hurricaned Venice

ps. DALI Factory is gorgeous, they even answer the dam phone in less than 3 rings.

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