Axiom Audio - Home Theaters
Axiom AudioFile Newsletter
Published Monthly Since 2002
Issue 74 | May 2008
Axiom's Anechoic Chamber

In This Month's Newsletter


Just in time for Father's Day!
Garage Speakers from Axiom Audio


Everyone needs an area in their home to escape. For women, it may be the bed/bathroom area. For men...the garage/workshop? We've developed a garage tread- patterned version of the M3 speaker, perfect for listening to tunes while you work on your '74 Mustang in that last bastion of manhood, the garage . . .

Order your limited edition finish for Dad today!

Not quite Dad's speed? Don't forget Axiom Gift Certificates, perfect for any occasion!


New product - The Sturdy Little Bracket!

Sturdy Little BracketYou asked for it and we've delivered it - the new Sturdy Little Bracket, a small bracket that's perfect for installing our Outdoor Algonquin Speakers by the pool, the dock, or the deck. Don't let its small stature fool you though - this little engineering marvel will hold up to 60 lbs when properly installed into a stud. Special introductory pricing: $48 per pair or buy it with a pair of Algonquins for just $36 per pair! Click here to learn more about this remarkable new bracket.


Product Reviews

Audio-Ideas.com reviews the Axiom Audiobytes

Axiom Audiobyte Computer Speakers in Burled Walnut
Axiom Audiobyte computer speakers in Burled Walnut. Amp is included; subwoofer optional.

". . .the Axiom Audiobytes have resolution and clarity to burn in the midrange and they sound a great deal more like a very good pair of mini-monitors than they do computer speakers . . . it manages to deliver remarkably clean, neutral, high resolution sound in a very flexible and attractive package. With Axiom's free shipping policy and a 30-day in- home trial period, it's a persuasive argument for better sound from your computer or iPod." -- Aaron Marshall, Audio-Ideas.com


Featured Article

The Decibel (dB) and the Violin/Piano Recital
by Alan Lofft

Alan Lofft

One of the most difficult-to-understand terms for newcomers (and even experienced enthusiasts) in audio and sound reproduction is the decibel, partly because it’s a measure of relative intensity or power in both acoustics and electrical circuits. It may help to understand it better if you know how the engineers at Bell Laboratories, back in 1924, came up with the term from which the decibel was derived.

One “Bel,” named in honor of the brilliant inventor and communications pioneer Alexander Graham Bell, represented the relative reduction in audio level that a mile of telephone cable imposed on the telephone audio signal (and you were worried about 30 or 40 feet of speaker cable!). It became shortened to “decibel”, which represents one-tenth of 1 bel (1 bel = 10 decibels). So a decibel expresses relative intensity, and it’s logarithmic in nature, based on multiples of 10. In terms of loudness and acoustical intensity, the decibel can conveniently express a huge range in sound pressures to which the ear responds (far greater than one million), from 0 dB (the threshold of hearing in young, undamaged ears) to 120 dB, the loudness of a jet engine or front-row seating at a rock concert. An increase of 1 dB can also be thought of as a just barely noticeable change in loudness, or the sound intensity generated by a mosquito flying at a distance of about 3 meters, or 10 feet. Can you hear a mosquito in a quiet cabin flying 10 feet away? Young, undamaged ears likely can.

On a more practical level, we often wonder how amplifier power output in watts relates to changes in the acoustical output (loudness), of loudspeakers. Now for the really amazing part: although it seems that doubling the amplifier power in watts would also double the loudness, disappointingly it only increases loudness by 3 dB, a change in volume most of us perceive as “slightly louder.” That’s why going from an amplifier of 75 watts output to one of 150 watts output only increases the actual acoustic output a bit—again by 3 dB. To make sounds subjectively “twice as loud”—an increase of 10 dB—requires ten times as much power from the amplifier. So if your speakers are using 5 to 10 watts (a fairly typical value) to produce reasonably loud sound in your average-size room, and you want to make your music twice as loud, you’ll need ten times as much power, or about 50 to 100 watts. That’s why it’s important to have plenty of reserve power in your amplifier/receiver to handle the peaks in loudness that may be at least 10 dB louder than average levels. In fact, I have on a classical CD recording where the loudest portions of the music are almost 30 dB louder than the quietest passages. Think about how much amplifier power that requires cleanly reproducing the 98-dB peaks in my 2,200 cu. ft. living room. Bring on the Axiom A1400-8!

Most of us have seen the charts that document the relative loudness of various common sounds—rustling leaves, 10 dB; a very quiet library, 30 dB; average conversation, 60 dB; street traffic, 85 dB, a full orchestra, 98 dB, and so on. But it’s fun to actually measure the relative loudness of various types of music heard live; moreover, it’s amazing how accurate even an inexpensive sound pressure meter is, and how closely the values relate to our subjective perception of “quiet” and “quite loud” music and to universally measured sound pressure levels.

A practical illustration of real-life volume levels of two acoustic instruments occurred at a violin and piano recital I attended by a young virtuoso violinist, Yuri Cho, and her accompanist, Michael Tan, at Merkin Concert Hall, a small 300-seat venue in New York City. Mr. Tan played a big Steinway concert grand piano. Ms. Cho was standing about 5 feet in front of the piano. I sat in Row B, only about 15 feet from the two performers. In the background hush before the recital began, I could easily hear the whirr of the hall’s air-exchange system, which was constant and measured 55 dB (all C-weighted), the latter quite high compared to some of the newest halls with baffled air-exchange systems that are almost silent at 35 or 40 dB. With my RadioShack meter in my lap, during the pianissimo sections, where the two recitalists played very quietly, the sound levels averaged about 70 dB; when things got loud (forte), the measurements rose to peaks of 87 and 89 dB, which certainly sounded very loud.

The higher strings of Ms. Cho’s violin had a somewhat hard and steely edge from my seat in Row B, so after intermission I moved to row F, which about doubled the listening distance from the piano and violin to 30 feet. According to acoustical laws (the inverse square ratio) the sound levels should have dropped to one quarter of their previous values (in an anechoic chamber that would happen) but in the hall, sitting midway back in Row F, my ears were receiving a much more rounded blend of direct and reflected sounds. Amazingly, the measured levels were only slightly less loud. On dynamic peaks in Gershwin’s wonderful Three Preludes, the sound levels still peaked in the range of 85 dB, only about 3 dB less loud than sitting up close. In Row B, the direct instrumental sounds were very dominant, with very little ambience, which is why the violin sounded hard (yes, some real instruments can sound harsh and edgy close up; I ought to know, I studied violin for 15 years). Back in row F, my ears were receiving lots of reflected sounds from the hall’s side walls, which, combined with the direct sounds to produce a much more pleasing blend, with hints of the small recital hall size. 

Next month, we’ll examine the “0 dB” indication on lots of AV receiver volume controls, and how that relates to actual sound levels in your listening room.


Audiofile AV Tip of the Month

New Online Site Offers High-Resolution Music Downloads to Audiophiles and Enthusiasts

As the record industry wrestles with dramatically declining CD sales and attempts to block or police exchange of free MP3 music over the internet, one innovative new approach developed by David and Norman Chesky, the owner/founders of audiophile label Chesky Records, may signal the future of music delivery to enthusiasts who demand superior sound quality to the typically mediocre overcompressed 128-kbps MP3 music files.

The web site, HDtracks (www.hdtracks.com), offers audiophile-quality music downloads from about 60 independent labels from around the world, all free of Digital Rights Management (DRM) restrictions that would otherwise limit playback of the downloaded music files.

Music can be downloaded in high-definition uncompressed AIFF files (compatible with iTunes libraries, iPods and Winamp), lossless FLAC format files (compatible with Media Monkey, VLC, Songbird, Mac Flac, Toast and Winamp) for playback on home audio systems, including PCs, Macs or music servers, or as 320-kbps MP3 files that far exceed the quality of standard MP3 files for playback on iPods and other portables. (The 320-kbps data speed is generally considered the minimum necessary for transparent music playback free of artifacts.)

Album pricing ($11.98) is reasonable and individual tracks are available at $1.49 each. All albums download with a PDF of full liner notes and album art, something not offered elsewhere online. The interface is simple to navigate and download as well. Initial listening on my part to album excerpts via lossless FLAC files confirms the very high quality of music playback.

You can get a taste of the high-res audio quality available from HDtracks by going to the site (www.hdtracks.com) for a free album download that will be offered through the end of June. HDtracks' "Ultimate Download Experience" has eight tracks representing different genres of music, all hand-picked to demonstrate the fine audio quality available. Be sure and choose the download format that is compatible with your computer and portable music player.


In past Axiom AudioFile newsletters and articles, I’ve recommended some Chesky recordings and in fact use several as audition discs for Axiom’s double-blind speaker comparisons. Quizzed on the launch of the HDtracks site, co-founder David Chesky noted: “Serious efforts have been made throughout history to deliver a pristine live-music experience, from the design of concert halls with perfect acoustics to the building of precious hand-made instruments, to the years of work put in by performers to perfect their craft. We offer the best alternative to those music enthusiasts who will not compromise and accept recorded music that is compressed, flat, lifeless, and represents a mere fraction of the original performance.” - A. L.

New Video

Alan Lofft's Latest video - getting the right speakers for your room.

See the latest video at Axiom - Guru Alan Lofft explains how to pick the right size loudspeaker for your room.


Special Spring Promotion!

For a limited time, upgrade to our new Algonquin Outdoor Speaker custom finish, Slate Black, at no additional charge! Click here to see the new finish and order your pair while the sale is on!


Financing At Axiom!


The Archives

Selecting Your Home Theater:

Home Theater Basics

What to Look For When Buying a Receiver

Spotlight on: Home Theater Buying Tips

Choosing a TV

Ten Tips to Getting a Big Screen TV 

Buying a DVD Player

DVD-Recorders

Do I Need Two Subs?

What's in a Cable?

Cable Quandary: Composite, S-Video, Component Video,
DVI, and HDMI Connectors


Choosing A Home Theater: Ten Mistakes to Avoid

Why Wall Units are the Enemy of Loudspeakers

Going the Separates Route

Beginners' Guide to Home Theater

Budgeting and Building a Dedicated Home Theater Room

Five Steps to Buying a Great HDTV

Ten Things You Need to Know About 1080p

Stereo Devotees - You Might Just Prefer Music In 5.1!

Home Theater Setup Guides:

An Essential Guide to Home Theater Layout


Stereo Setup Guide

Subwoofer Connections

How to Manage Video Connections

Five Totally Simple Ways to Get a Better TV Picture

Subwoofer Placement Tips

Running Multiple Sets of Speakers in Other Rooms

What is Impedance

Choosing Surround Sound Modes

The Forgotten Component: Getting Room Acoustics Right

Basement Home Theater

AV Connections

5(.1) Ways to Improve Your Home Theater Experience This Weekend

Five Steps to Beautiful A/V Installations

Soundproofing your Home Theater: The Basics Part 1

Soundproofing your Home Theater: The Basics Part 2

5.1 Symptoms That Your TV Display Needs Proper Setup

Bringing Sound Outdoors


The Tech Talk:

Axiom Speakers and the NRC

Bass Management


Understanding Frequency Response

Secrets of Amplifier and Speaker Power Requirements Revealed

Soft to Loud: The Nature of Power and Dynamic Headroom

Excavating Real Deep Bass

How to Judge Loudspeaker Sound and Accuracy

Describing Speaker Sound

The Inside Dope on Surround Speakers


DVD -Audio vs Super Audio CD (SACD)

Stereo's Intrinsic Flaw

Dolby Pro Logic II

Standard or High Definition--It's All in the Pixel Count!

Analog to Digital TV: How to “Get” HDTV

What Defines a Reference Loudspeaker?


Surround Theory - Surround Speaker Placement

How Much Distortion Can we Hear with Music? (Experimental Study)

A Projection Room for Your Basement Home Theater

Treated vs Untreated: A Comparison of Two Identical Listening Rooms


“Tight” or “Flabby” Bass: Does It Exist?


All contents © Colquhoun Audio Laboratories 1999-2008