Shawn Kernes Blog

The addition and integration of subwoofers into a stereo system is one of the most misunderstood things in audio. To make life easier, i have developed a rule-of-thumb to help simplify things a bit. Begin by calculating the surface area of the woofers in your speakers. For those of you who are a bit rusty with middle school math,  A = π r².   For example, if we have a 6" woofer in each of the front (L/R) speakers, then A = 2 * 3.14 * 3 * 3 = 56.5 sq/in. If we have a pair of 8" woofers in each front speaker, then A = 4 * 3.14 * 4 * 4 = 200.9 sq/in.  The rough range for the ideal size of a subwoofer is between 1x and 2x the area of the front woofers.  Sticking with the example of 6" woofers, we would be looking for a subwoofer (or subwoofers) with an area of between 56.5 and 113 sq/in. We can convert area to diameter with the following formula: D=2 (sqrt(A/Pi)), which in this case works out to 8.5" to 12" Now that we have a rough range, let's try to narrow th

I am often asked questions like "is this amp powerful enough for my speakers?" so i thought i would take a moment to write up a definitive answer.  To begin answering the question, it's important to know how loud you want your system to be at your listening position. This can be different for everyone, but using the THX reference level of 85db with 20db of headroom (max 105db) as a starting point is pretty safe.  https://www.thx.com/questions/what-is-the-reference-level/ Without getting into all the math... Doubling amplifier power boosts output by 3db. Using 2 speakers in a stereo setup will boost output by 3db. Positioning speakers close to a wall will boost output by around 3db positioning speakers in a corner will boost output by around 6db. And output will decrease by 6db for each doubling of distance between the listener and the speaker.  Its kind of a lot to remember, but fortunately there are tools, like this one that do all the work for you:  http://myhometheater

  “Affordable” Phono Preamplifier Review I always find it tough to start a new audio equipment review, partially because i find writing hard and partially because there is such a broad spectrum of needs, desires, and knowledge in this hobby. So… Bear with me, i'm going to try to make this particular review work for everyone, if a section is too rudimentary or doesn’t apply to you, skip it (or read it anyway, since i took the time to write it).  What’s needed to play a record?  In general, every two channel audio system requires a pair of speakers, an amplifier, a preamplifier, an audio source, and a bunch of wire to connect it all together.  Yea, i know, it sounds like a lot of stuff, but not to worry... There are plenty of products (such as the Sonos Amp, Bluesound PowerNode 2i, and Amazon Echo Link Amp) that house everything you need, with the exception of speakers, to listen to music via your favorite streaming service, in one small box.  Playing records (aka vinyl or LP’s, neve