Mission 770 loudspeaker Associated Equipment

Sidebar 2: Associated Equipment

Analog source: Linn Sondek LP12 turntable with Lingo power supply, Linn Ekos tonearm, Linn Arkiv B cartridge, Channel D Seta L phono preamplifier.
Digital sources: Roon Nucleus+ file server; Ayre Acoustics C-5xeMP universal player; MBL N31 CD player/DAC; dCS Rossini Apex, Bel Canto e1X DAC D/A processors; Ayre Acoustics QA-9 A/D converter; NetGear Nighthawk router.
Power amplifiers: Parasound Halo JC 1+.
Loudspeakers: Audiovector QR 7, Q Acoustics Concept 50.
Cables: Digital: AudioQuest Vodka (Ethernet), AudioQuest Coffee (USB), DH Labs (1m, AES3). Interconnect: AudioQuest Wild Blue (balanced). Speaker: AudioQuest Robin Hood. AC: AudioQuest Dragon Source & High Current; manufacturers' own.
Accessories: Mission 770 loudspeaker stands; Target TT-5 equipment racks; Ayre Acoustics Myrtle Blocks; ASC Tube Traps, RPG Abffusor panels; AudioQuest Niagara 5000 Low-Z Power/Noise-Dissipation System and AudioQuest Niagara 1000 Low-Z Power/Noise-Dissipation System (source components). HDPlex linear power supply for Roon Nucleus+; AudioQuest Fog Lifters cable supports. AC power comes from two dedicated 20A circuits, each just 6' from breaker box. Room: 20' (left side), 25' (right side) × 16' × 8'.—John Atkinson

COMPANY INFO
International Audio Group/Mission
North American distributor: Erikson Home - An Exertis | JAM business
Canada
ARTICLE CONTENTS

COMMENTS
remlab's picture

I hate asking questions like this, but why do PM's FR measurements always look so much worse than your own? The upcoming Paradigm Founder measurements will probably be no different

Kal Rubinson's picture

There may be other differences but the difference in scale is significant.
Amplitude (vertical scale) spans 30dB in HFN and 50dB in Stereophile. Frequency (horizontal scale) spans 20Hz-60kHz in HFN and 10Hz-30kHz in Stereophile.

As a result, the HFN display would visually emphasize the level deviations even if the data were the same. Also, HFN seems to apply more smoothing.

remlab's picture

but it's the "Other differences" I'm referring to. Big deviations that aren't very difficult to glean from the measurements, even taking into account the differences in scale

John Atkinson's picture
remlab wrote:
but it's the "Other differences" I'm referring to. Big deviations that aren't very difficult to glean from the measurements, even taking into account the differences in scale

As well as the different graph scaling mentioned by Kal Rubinson, while there's no smoothing in my speaker response graphs, while Paul Miller at HFN takes his response measurement at a single point in space, I average mine across a 30 degree horizontal angle on the chosen axis.

I wrote about why I do this in the paper on loudspeaker measurements that I presented to the AES in 1997 - www.stereophile.com/content/measuring-loudspeakers-part-three-page-2:

"There is a problem with taking the response at just one point in that there is almost too much information. Some of the fine detail will be specific to just that one point in space. With a loudspeaker whose drive-units are mounted in some kind of vertical array, it seemed sensible to implement some kind of spatial averaging. This would smooth out any position-dependent wrinkles in the measured response, while leaving the significant information intact. Accordingly, my published responses are the average of seven measured responses, taken at 5 degree intervals across a 30 degrees horizontal window on the reference axis."

John Atkinson
Technical Editor Stereophile

Glotz's picture

I'm still a little fuzzy on the 'too' much information bit that a single point axis responses yield, in the first line of that paragraph from your paper in 1997. I've read that line several times over the years and perhaps I still have confusion here.

The multiple-point measurements minus position-dependent wrinkles seem easy to understand, but it's really the remainder of products (50-degree window) in comparison with the on-axis measurement that gives us a greater definition of the frequency response?

The concept of a wider window in space seems easy enough, but I'm not sure that's it. Does it rather define the direct-on-axis response?

Anton's picture

When I saw the post, I thought it was one of JA1's post of vintage reviews.

Then I got to that review in my new Sterophile and realized.

It's almost a dead ringer!

smileday's picture

Does the peak at about 6-7 kHz in Fig. 4 change if we put on the grille?

I see similar peak at about 7-8 kHz in Stereophile measurement of Spendor D7, SP100R2, and A7.

Not normalized to on axis response, and with and without grille comparison might help understand those speakers.

John Atkinson's picture
smileday wrote:
Does the peak at about 6-7 kHz in Fig. 4 change if we put on the grille?

It's not a frequency response peak. Rather, as this graph is showing the speaker's horizontal radiation pattern normalized to the on-axis response, it is showing that the suckout in this region in the on-axis response fills in to the speaker's sides.

John Atkinson
Technical Editor, Stereophile

smileday's picture

Thanks. What about the ~ 8 kHz 'peaks' of Spendors? Are they peaks, or a fill of on-axis suck-out?

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