December 1999

Stereos As Strenuous Sport: Sand Bagging The Sound.
Review By Colin Flood
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  From the Bob G., Webmaster at the Klipsch BBS, comes this inexpensive bit of tweaking advice; add sandbags to the top of your big speakers.

"The main concept, he writes, is to keep the speaker stock still. If the woofer moves back and forth, by Newton's laws of motion, the whole speaker will try to move in an equal and opposite direction. 

"Now, think of how little motion there is in your tweeter diaphragm or mid range diaphragm. If the whole speaker is rocking more than either of these two drivers move, what does it do to the sound? Well for one thing, it introduces Doppler distortion (a form of IM) that hurts the sound a great deal. The tweeter and mid are moving forward and back due to speaker movement while trying to impart their output to the air in the room - quite a confused mess. 

"Keep the speaker still and this distortion will go away for the most part. Spikes can help. I've heard of people putting bags of sand on top of their speakers. Crazy but good. I modified a pair of Forte's to have sand filled bases. Helped a lot."

And he writes, "this is a case where more is better. Use about 80 lb. of sand on each speaker. Be careful of your back and also watch for leaks in the bags of sand. You'll hear better focus, detail precision and leading edge transients. You'll probably find the result more dynamic and you'll hear more at low volumes."

Following this advice, I hot footed to Home Depot and selected two of the largest bags of Bonsai play sand (60-lbs.)in stiff plastic bags for $5.49. Appropriately, the bags indicate they are for "recreation areas."

First impression was the bags were dusty and heavy. Second impression was that they improved the handling and feel of my little Mazda pick-up by holding down the rear end. If I lived in a snowy climate again, this is one truck tweak I would strongly recommend.

I sat the bags on the floor - be careful of the stiff plastic as it tears easily - and slid a pair of matching pillowcases over the bags.

The test track became Tracy Chapman's throaty and gentle "The Promise" from her 1994 New Beginnings CD (Elektra). This was a recent CD I repurchased after my daughter discovered Tracy. I have not listened to the CD since it was missing years ago. I hefted the bags up on to the 2 1/5 foot wide tops of my old Klipsch horn loaded Cornerwalls. I listened for tone and contrasts by alternating the bags on and off.

My Dynaco pre-amp uses a type "A" volume control that closely approximates the power level of the amp. At 9:00 on the dial (higher than normal listening level), my wife covered her ears, saying "it was too loud" without the bags.

The sandbags did do something. I did not hear better focus, detail precision and leading edge transients. I did not find the result more dynamic or hear more at low volumes. But I did hear something and so did 'miss sensitive ears'. 

I played selections from one of my all time favorite's: the amazing "20 Bit Taste of DMP" sampler CD (http://www.dmprecords.com/dmp_collections.htm). This is one of the CDs I carry with me to test other systems. It is clear - it is clean. There is more silence in the quiet passages than almost all of my other CDs, while the highs provide ice cold contrasts to the deep and rich bass plunks. I love every other song on this silver disc and play it regularly. All other systems always sound their very best when playing this CD. It has deep and fast kick drums, high and sweet chimes, smooth female vocals and resounding pianos. 

But I barely heard perceptible differences with the sand bag solution and this CD. More 'listenable' perhaps, but hard to lasso, tie down and put a brand on - after all, this CD is already a personal favorite.

But, with the heavy bag hats on, Tracy's voice however, did sound slightly more 'solid' somehow - nothing measurable - but a little richer, as if the woofer was adding paper cone vibrations in with the metal mid-range horn. 

I want to write that it was like adding chocolate icing on Tracy's chocolate cake. I want to write that, but it is not true. It was something added to the favor, but it was not icing. And it is not that the sand bags correct something that was missing - because they didn't. Nothing was missing before, but something was added now.

My notes say the cheap tweak is "some of the alchemy where art transcends science - a taste of the audiophile magic." With OUT the sand pillows, New Beginnings sounded 'lighter'. I did notice instruments playing farther apart on this CD, but I can't honestly say I notice such obvious differences on my usual test CDs.

The tweak did not make my speakers sound like wonderful, brand new, super audiophile models. Although wrapping my mid and high range horns with window putty did improve them dramatically; this tweak was not as dramatic. Nor was it as obvious, as the clarity that new Monster cables brought, either. 

But it was there, and the bags will remain. In fact, I may add another pair of 60 Lb. bags, when my wife has four matching pillowcases that suit the living room.

With top of the line Dunlavy SC-IVs weighing 550 lbs., damping the speaker cabinet and making it more solid does have a positive impact on the sound. (Perhaps the new Klipsch Khorns will come with sealed chambers so new owners can pour in sand after the speakers have been shipped and set-up.)

Sand bagging big speakers is a extremely low cost, simple, easy to do and a strange, but effective, tweak. 

Recommended: Thank you Bob G., Klipsch Webmaster.