Stereophile Class A and Frequency Response


According to the Recommended Components Loudspeaker section in Stereophile, "to be eligible for inclusion in Class A, the system must be full range- ie feature bass extension to 20Hz."

I then noticed that the B&W 802D which is in Class A has a frequency response of 34Hz–28kHz (as mentioned in Stereophile's report on the speaker), which is nowhere near 20Hz.

Why is this speaker included in Class A?
smeyers
I just received a CD (Boadwalk Pipes and Bach on the Biggest" ACCHOS/CD/02). The two organs are in the convention center at Atlantic City NJ. The original master tapes, digitally remnastered for this CD, were made in 1956 by Mercury's renowned team of Wilma Coozart and C. C. Fine using their three channel recorder of Living Presence fame. Proceeds from sale of this CD go towards restoration of the organs.

The larger of the two instruments has a 64 foot pipe, 36" square at the top, which sounds at eight (8) Hz. My audio rig, with a custom subwoofer system that includes three 15" drivers and three 12" drivers, powered by six 600 watt amps, had to be turned down a bit from what I would consider realistic SPL for this instrument. Awesome. Try this CD with your 6" woofer!
.
Let me explain the discrepancy between the Stereophile measurements and the Ultra Audio measurements.

John Atkinson uses a simulated anechoic technique, employing time-gating over most of the spectrum and close-miking the woofer and port in the bass region, then doing some calculating and splicing. So the deep bass response in Stereophile's measurement section is the expected anechoic response (no room contribution).

In his Ultra Audio review, Paul Messenger states that he used a "farfield in-room technique" - in other words, the room's contribution was included. This is the reason for the discrepancy.

Typical room gain for a monopolar speaker system in a home listening room is roughly 3 dB per octave below 100 Hz or so. At 20 Hz, this comes to 7 dB. Note that room gain varies from room to room. Apparently in Paul Messenger's room, and with his speaker and microphone positioning, he gets about 10 dB of room gain at 20 Hz.

Here's a link to a "typical" room-gain curve: http://www.speakerbuilding.com/content/1020/rge.gif

If we add the expected 7 dB of room gain to the -10 dB that Stereophile recorded at 20 Hz, we come up with -3 dB.

So in a real-world situation, the 802D meets Stereophile's criteria for classification as a "full-range" loudspeaker.

Duke
dealer/manufacturer
Eldartford

Ya, I used to read "Audio". I remember when they reviewed the old Snell Type A's...My speaker lust of that time.

I liked Stereophile a lot back then too, it was a smaller size (6"x 10", maybe smaller?)...easy to hold.

Dave
I don't believe what they say, but unfortuantely Smeyers is right, far too many do believe them.

FWIW, I find far better reviews and knowledge on threads here and at Audio Asylum. Sure, you will occasionally have the cloaked dealer, but overall there are far fewer hidden agendas here, IMHO.

Cheers,
John
Do you actually believe anything Sterophile says anymore. They promised a review of the Krell KCT years ago and when they didn't deliver they lost my subscription. And have you seen the latest issue, it bears no resemblance to this once fine journal; it is flimsy and thin, why even bother?
"If you find yourself taking their recommended component section seriously, you should rush to the nearest audio store and listen for yourself."

The problem is there are so few brick and mortar shops around anymore, so more of us rely on reviews, reputation, etc. and take a chance with our purchases. If you don't live near a good size city, the choices are even fewer. Also many of the shops that still do exist often do not carry the product that you want to audition.

I do realize that Stereophile is a business like any other and will do what it can to increase the bottom line, especially in an age where many have turned to big TV, internet, and iPods for entertainment. I would be nice to think that in this niche hobby, they would rise to a higher level of ethics.

Anyhow, this thread veered off topic a bit; my original question was answered!
Call me jaded then, but I've been a subscriber for over 20 years, and I've seen the magazine grow into a glossy business rag. I wouldn't put integrity in the same paragraph as Stereophile anymore than I would put business and ethics together. Just as many other business' have learned to profit off their past reputation, so has Stereophile, they sold out a long time ago.

They do take good photos, 'audio porn' if you will. Also, they are somwhat helpful when reading about functional descriptions, balance control, phase invert switches, etc. You really can't take any of their subjective comments seriously though, and their recommended components is the pinnacle of all shams.

If you find yourself taking their recommended component section seriously, you should rush to the nearest audio store and listen for yourself. Then you'll realize it's all just a hoax. Yes, I do realize that they do have a strong influence, but this can also work for you. For example, take that last item that you like, and have been dreaming of, wait for Steerophile to review it, if you're lucky and it gets a poor review, then you'll save a boatload of cash when buying it.

Of course, if it helps you to sleep at night knowing that someone else thinks your stuff is 'da bomb', you can always pay more to have Stereophile endorse it.

Yes, the B&W 802D's do not belong in the Class A speaker section, according to the magazine's own policies. That should tell you all you need to know about the legitimacy of Stereophile's 'Recommeded Components' section.

I hope you don't take David Letterman's Top 10 lists this seriously too....
Also, I guess while I'm bursting your bubble on the 'Stereophile illusion', I might as well break the news that there is no Easter Bunny, Santa Claus or Tooth Fairy either.

Cheers,
John
I don't subscribe to Stereophile, but, I can imagine that they just might be as capable of human error as anyone of us might be.
"Why do you find this so disturbing? Do you have some form of biblical belief in Stereophile?"

For better or for worse, the ratings in Stereophile have a strong influence on the buying decision of many. If they make a claim that they will only include products that meet a specific specification within a certain elite group, they should stick with that. For me it's a general issue of integrity, and I it makes me feel less positive about the folks that run the magazine.
03-05-08: Smeyers
I find this disturbing that Stereophile would put the speaker in this category.


Why do you find this so disturbing? Do you have some form of biblical belief in Stereophile? They are prone to the call of the dollar just as any other business.
If you wouldn't put them up on a pedestal, they wouldn't let you down.
Their recommended component section is just for shiggles.

Cheers,
John
Kinda like the Car companys all claim at least 3 miles per gallon better than they actually get on an average useage.. Never believe everything unless proved in truly optimal environments and that means the ones we actually use not some perfect built isolation booth.
Eldartford- I agree 30hz is good enough for most music, I listen to J.S Bach's wonderful Organ music so like to feel the additional true sub-bass.
Gawdbless,,,It's that last octave, down to maybe 16 Hz, which lets you FEEL some organ music. If you don't play that kind of music 30 Hz is plenty good.
B&W has always been a favorite of Stereophile and they do make great speakers. However, to include a speaker with limited bass in that category is misleading, at best. By their own measurements, the 802D is -10 dB at 20 Hz!

http://www.stereophile.com/floorloudspeakers/1205bw/index4.html

Soundstage/Ultra Audio measured 0 dB at 20 Hz.

http://www.ultraaudio.com/equipment/bw_802d.htm

Who to believe? Also, there is a hump at 60-70 Hz which gives the feeling of fullness in the bass and may compensate for the roll-off above Stereophile's measurements. I would argue that -10 dB is significant at any frequency. Companies should tell the customer whether the measurements are anechoic or in room, +/- 1 dB and +/- 3 dB, and if that is flat across all frequencies. It doesn't tell you if the speakers sound good, but is a basis of comparison between speakers. Personally I find deep bass indispensable to all music I listen to and for my money, if a speaker is down 10 dB at 20 Hz, it needs a subwoofer. Just my opinion. (Lets the flames begin!)
The definition of "bass extension" is a bit subjective, and said to be responsive to advertising revenue.
The frequency response graph in the Stereophile review suggests a -3 db point a little lower than 34Hz, but clearly nowhere near 20Hz. I find this disturbing that Stereophile would put the speaker in this category.
Yes they still have 'Full Range' and 'Restricted Extreme LF', the B&W 802D's are listed under 'Full Range' which does have the 20 Hz stipulation. Yes the B&W 802D specs are 34Hz-28Khz +/- 3 db.

My guess, as with all things Stereophile, would be that advertising dollars speak louder than guidelines.

Cheers,
John
Don't they have Class A fullrange, and Class A non-fullrange?...they used to?

I have not bought Stereophile in a few years.

Dave
Does Stereophile specify what the deviation from 'flat' can be at 20hz and still qualify for 'Class A'? Perhaps your 802's fall within their range. Normally one thinks of +/- 3db when talking about a frequency response range, but for example down 6db (or even more, depending on your room size)20hz is still excellent output. FWIW.