Math question

[Tom Brennan]

People lie.

Ever notice that the same shills pop out whenever AN speakers are mentioned at AA?

When I want to listen to chinless cones and tragic domes I listen to the $200 KRKs I bought at Guitar Center.

[MANZANITA]

I have seen similar claims.... but as always... Hoffman's Iron Law rules.... so.. you could engineer 8" driver to do this... but something has to give... in this case.. it would have to be Xmax. No way around it IF you are flat at 25HZ AND maintain 98 db/Watt. If your woofer is 3-4 ohms it makes it easier by three db to get a SENSITIVITY of 98 db with a standard 2.83 Volt imput signal. All this assumes the speaker is radiating into a quarter space environment... up against a long wall .... sitting on the floor. If you are eigth Space.... in a corner sitting on the floor it gets that much easier.

Suspect if you do real measurements... If this system were to reach a true 94 DB/watt with say a 4 MM Peak xmax that would be as good as you could do... and again this assumes quarter space environment. One other way to show a flat (relative to average midrange level) at 25 hz is to use an extended bass shelf alignment with a large peak at 25 hz... but you will have a large dip in the rest of the bass response... there is always a trade off. Interested in hearing (no pun intended) other view points on this.

[selmerdave]

Measurements were published by Art Dudley in Stereophile.

http://www.stereophile.com/standloudspeakers/506an/

They were done in corners so there is room reinforcement, but it is still surprising to me.

Dave

[Tom Brennan]

I didn't see where Dudley measured the sensitivity, that's where the lie would be.

I can see an 8" woofer getting as low as claimed but not in that size box and with that sensitivity. Note that I've never seen a 98db dome tweeter either, even horn loaded domes like the Vifa, Morel and Dynaudio aren't that sensitive.

DJK over at AA often runs the math on these false claims.

There are several people fudging sensitivity ratings lately----Zoo and Klipsch are spinning it too. Note that Klipsch claims their new Heresy is more sensitive AND goes deeper while using the same size sealed box. Ole PWK must be spinning in his grave.

[MANZANITA]

After reading the article.... 98 db sensitivity is not the same thing as efficiency.... and I suspect if the 98 is met... it is only in the mid band... and the spec is likely +/- the usual 3 db... so ... start at 98 db sensitivity... dollars to donuts the woofer is 4 ohms... so subtract 3 db..... subtract another 3 db at 25 hz and hey we are back in the real world with a efficiency of 92 db. The laws of physics are the laws of physics.... and I also suspect a low xmax value for the woofer to boot. Nothing new here..

[bfish]

Originally posted by selmerdave:
Measurements were published by Art Dudley in Stereophile...

<font size="2" face="Verdana, Helvetica, sans-serif">and were given a somewhat better analysis by John Atkinson on the measurements page. There, he notes;

"The Audio Note AN-E Lexus Signature was one of the more sensitive dynamic speakers I have measured, at an estimated 92.5dB(B)/2.83V/m, though it should be noted that this is well below the specified 98dB figure."

(if 92.5 is considered more sensitive, I wonder what he considers a power-sucker?)

and;

"The speaker's bass is well extended, but does shelve down below 120Hz. Bearing in mind that this trace includes the usual 2pi boost in the upper bass that results from the nearfield measurement technique, it looks as if the AN-E really doesn't produce as much bass as you might expect."

This is the first "professional" speaker review I've bothered to even briefly skim over in years, and in doing so I remembered all too clearly why I quit doing so... The next logical career move for a former "pro" audio reviewer is clearly in the political arena (or maybe vice versa). I can easily imagine Karl "pants on fire" Rove supplementing his Fox/Newsweek/WSJ blather with articles for Stereophile.

[Tom Brennan]

All this for only a little over 12 grand, such a deal.

Typical "high-end" nonsense; an overpriced lousy speaker for delusional twits who believe in "prat" and call patch cords "interconnects".

[selmerdave]

I have a non-Altec acoustic math question that I think likely could be answered by the knowledge here.

There have been a number of posts on AA recently about the Audio Note AN-E speakers, which I was surprised to find were measured flat to 25 Hz at 98 dB efficiency (-6db at 19 Hz). I am wondering about the mathematical possibility of that with a single 8" woofer in a 2.5 cu. ft. box, even with room reinforcement. Wouldn't that require some rediculous excursion? If not, why are there not multitudes of 8"-based speakers with those kinds of specs?

Thanks.

Dave

[RonSSS]

2 + 2 Be fo.

[selmerdave]

Thanks guys, a lot of good info and it's starting to make sense now. I haven't seen anyone bringing any of this up over there or challenging any of the claims, but it's most likely that it's just a tired old issue and that's been done before.

Thanks again.

Dave