Audiolics Anonymous Chapter 37
Stupid vs. Smart (Devices)
Article By Bill Gaw

  Over the past three years of writing for Enjoy The Music.com I have done several columns on the vices and virtues of the electricity that powers our craving for the absolute sound (see the archives). With each session we have found that:

1. AC is bad, DC is good.

2. Any AC floating on the DC except for the music is worse.

3. The ideal would be to have our entire equipment run by DC alone.

4. At present, this is impractical as batteries would be the only way to go.

  a. I'd hate to think how many of them you'd need for each piece of equipment, especially the tubes.

  b. Very few pieces of equipment produced today allow one to run off of batteries which would mean building new power supplies for each piece of equipment.

  c. Then you'd need some way of charging them all.

5. This may be alleviated in the future with new DC power sources such as fuel cells, solar, etc.

6. Protecting all of your equipment from the power surges and spikes that come over the AC line all of the time.

Some of these problems can be overcome by:

1. Obtaining better AC from your power company by complaining enough that they come to your house to change out or give you a separate isolation transformer at the pole. Believe me it takes a lot of complaining.

2. Running heavy gauge high-end AC wiring from your 200 amp plus service to your media room. I put a 60-amp line into mine directly off the house's 200-amp service.

3. Using only one leg of your 220-volt service for all of your equipment.

4. Making sure your house ground is doing its job, or having a separate ground for your AC equipment.

5. Using the best grade wall jacks and power cords to your equipment.

6. Doing everything possible to block out all AC except for the 60 cycle wave that is supposed to be coming into your house.

7. Having a surge protector, preferably at the house service.

Of course all this could be made moot if your power company gave you the ideal 60 Hz AC wave you are paying for, or if you could completely isolate yourself from the power company, but at this time this is impossible without going through more trouble than you could possibly imagine.

Well, I thought that I had improved my electricity to as close to the ideal 60Hz sine wave as I could, and had put in two levels of surge and spike protection at the service and at the equipment, thus isolating my system to the max from noise and disruption. I had even doubly grounded the television antenna inputs from my satellite dishes and off the air antennas.

Unhappily for my equipment (and me), I forgot one back door to equipment meltdown - the telephone hookup. Maybe this is not a problem with your audio system, as few need a connection to Ma Bell, but anybody who has an audio-video system with satellite or computer hookups probably has at least one connection to a telephone. Believe it or not, those flimsy little cables from your "connection to the world" can carry enough juice to fry your circuit boards, chips, transistors, etc. If you have an all tube system, you can stop worrying as it can usually handle the spikes and surges, but if you have one piece of digital equipment or solid-state. Beware!

So what happened? Well on Tuesday evening, as usual, I turned on my system at about 6 PM to let it warm up, and went downstairs to make up a pair of interconnects. About a half an hour later, I heard some rumbling suggesting a thunderstorm was coming, but didn't heed it. Well, ten minutes later, the house lit up and the silence was shattered when a bolt struck somewhere nearby.

While I live on a hill, with my antennas being the highest point for about a mile around, I had never been hit by lightening before. Panicked, I went outside in the rain to find my house had been spared. I don't know where the bolt hit, but it was close. Happy that we had taken no direct damage, I went into the house to enjoy my system.

Unhappily my baby had been struck by the surge. Wiped out were my C-band and DirecTV satellite receivers, and my home theater computer's audio board. The only thing they have in common is the phone line that connects each to the outside world. Luckily, the surge through the phone line was not great enough to travel from them through the interconnects to the other pieces of equipment, which are functioning properly, at least for now. Hopefully they haven't been damaged.
My grandfather, way back in the Fifties used to run around the house and disconnect all electrical appliances, especially our Philco B&W TV from the wall at the first sign of a storm, and I can still remember laughing at him. Guess he's laughing up there now. Anyway, moral of the story:

Surge protect any possible entrance of electricity into your system.

1. AC from your service.

2. Cable or antenna inputs.

3. Last but obviously not least, telephone jacks.

Enough said.

Smart Devices Subwoofer Power Amps and MM-1 Analog Music Matrix Box

Smart Theater Systems, of Norcross, Gordia is a producer of audio equipment for high end movie theaters. Over the past couple of years they have gone into home theater, developing amps, subs, and surround sound decoders. Back in Chapter (VIII), I reviewed the Smart Devices CS-3X Jr. surround sound decoder a neat little box that uses a Circle Surround analog processor that will allow you to get either a center surround from the side surround channels of 5.1 recordings to get 6.1 processing, or to get left and right surround channels from left and right front channels. If one gangs the boxes one can also get a center front channel, center left and right channels between the front center and left and right channels, and a center left and right rear channel if one desires. All one needs is several of these $300 boxes, interconnects, and the subtle decrease in clarity of the main channels when the signal is passed through each box. In return one can become enveloped with surround sound which is actually quite natural when used subtly with the best two channel analog and digital source material.

While at the PRIMEDIA NYC show, I happened upon their room and found that they have added the above two products to their line-up. The first is a "Class D" pulse width modulating 600 watt amplifier specifically designed for their 18 inch cinema subwoofers, but which they will now be selling as a separate unit for home subwoofer builders and as replacements for Kintek subwoofer amplifiers. Being 90% efficient, and thus very cool running, they are built for placement inside a subwoofer cabinet and therefore don't come with their own. They are only 10x10x6 inches, with one circuit board, but have a huge transformer, which make each 15 pounds without cabinet.

There are screw-on balanced inputs, so they can be run with either balanced or single ended equipment, but the connector will have to be removed and the interconnect ends attached with screws. Outputs are fast-ons, so again, typical spade lugs will have to be removed. Obviously this will be damaging to both interconnects and speaker wire, but they were built this way to prevent disconnection in their natural habitat - movie theater sound systems, and the connections will be super secure. A built-in crossover limits frequency range from 20 to 200 Hz., and an input sensitivity switch allows full 600-watt output from either 500mv or 1 Volt input. Distortion figures are given as 0.1% at 1 watt and 1% at 600 watts output.

As I was going to use them in place of my Crown Macro-reference 750 watt/channel/ 1500 watt max per channel amps, on my pre built subwoofers, first in line was to build a pair of cabinets for them. Then I made up a pair of interconnects with the appropriate ends, and ran them single ended as I don't have a balanced subwoofer pre-amplifier.

So how did they compare to my Crown Macro Reference, one of the most powerful amplifiers out there. Astonishingly well. Bass was tight, with the only problem being matching the power output of them to the Crowns. The low sensitivity was just a tad low, and the high a tad high. So I had to place a preamp in between my preamp subwoofer outputs and amplifier input. Its too bad they didn't use a volume pot instead of a two position switch, but most systems probably have some way of adjusting subwoofer volume anyway.

Once output was balanced with the Crown's, for the life of me I couldn't tell which amp was pumping out the bass. This is a tremendous compliment for the Smart units, as the Crown is a superb solid-state amplifier with the best bass reproduction I have heard, thus the reason I use it with my main subs. Remember, the Crown was $2,900 several years ago. And as the Smart subwoofer amplifiers? Just $697 each list direct form Smart Devices.

The Analog Music Matrix Box is a Circle Surround Processor designed for use on a home stereo system that is used for both audio and video. It is very similar in make-up to their CS-3X unit reviewed in Chapter (VIII). It takes a two-channel signal and, using the Circle Surround process, extracts a front center and two rear channels. Unlike Dolby Digital, their are two full range surround channels. The CS-3X can either be used to do the above, or also extract a center surround channel from the two rear channels, thus giving a 6.1 system. It also has a volume pot on the front to adjust the center rear channel output.

The CS-3x unit has one minor problem. It gives a hard center channel, meaning that it extracts all of the center channel information and projects it directly from the center speaker. This is great for movies where it is important for the voice to be centralized, thus not giving a phantom like sound if it were to come from between the center and front side channels. Unhappily, this detracts somewhat from the soundstaging of audio reproduction.

The Matrix Box has a switch for audio and video which softens the spread between the front three channels filling in the sound space between the side and center speakers, giving a more seamless soundstage, while still reproducing two rear channels.

The unit has separate volume pots for each channel on the back through small screw pots, and an internal signal for channel balancing. Unhappily it is a pain in the butt to play with the screws to get the sound field just right, but happily need only be done once as your stereo preamp volume controls will then control the loudness of the entire sound field.

So what can this unit be used for?

1. Playback of 2-channel analog or digital audio producing a 5.1 sound field. The unit does a much better job of this than Dolby Pro Logic units, and even produces a more life-like illusion than DPL II, possibly because it does it in the analog realm.

2. Playback of Dolby Pro-logic from satellite, off the air or Laser Discs in Circle Surround. Again, it does a better job than the DPL at decoding these signals. I don't know how, but it does seem to extract two different wide band rear surround channels, where DPL only gets one 20-7000KHZ channel. Go figure.

3. Extraction of a center rear channel from the two rear channels in a DD or DTS 5,1 mix. While the 3X was built for this, this unit is cheaper by $50 and does the same job. Only problem is that there is no front volume control for the rear channel like with the 3X, but this should not be a problem once the system is set up.

4. Extraction of front center-left or right channels. Many movies have embedded extra front channels in between the center and front side speakers that can be extracted. One can then separate the front left and right speakers further and add a speaker between each and the front center speaker. This should give a more believable sound stage, but with six-foot horns, I haven't tried it yet as there probably wouldn't be enough room for me to listen. If one had enough of them, or if Smart Devices comes up with a 10-output unit, one could become completely surrounded with speakers every 10 to 20 degrees. Imagine that sound field. (OK, you two channel Luddites should calm down and put away the tar and feathers.)

How do the two units compare soundwise. Except for the ability to control the spread of the front soundfield with the Matrix unit, and volume control with the CS-3x, they sound exactly the same in that they do decrease somewhat the clarity of the two main channels. Thus, I have been running the main channels directly from my preamp, and using the preamp's second output to run the matrix unit for the other channels. Thus, the best of both worlds. Undisturbed quality from the main channels, and an analog surround field from the others.

P.S.

I just thought of another possible use for the MM-1 or CS-3x: as a synthesizer of an overhead channel for height information, by using the front and rear center channels of 6.1 DD or DTS discs, one could possibly synthesize enough information to add an overhead front to back sound.

P.P.S.

I have just discovered that most Telarc multi-channel SACD's have incorporated a height channel into the subwoofer channel. I had shut down all of the other channel's amps to see how much subwoofer information this channel carries, and found a full range sound suggesting overhead sounds on four out of five of my Telarc discs, even though only one was labeled as such. It does make a difference in the sound field so you may want to try it if you have overhead speakers. More on this next month after some experimentation...

Finally, this month I just received a copy of a compilation of some of the songs from the ABKO Rolling Stones SACD series. Thank you, ABKO. I will do a full review next month, but I can say now that they have done very little in the way of gimmicking the sound, have been judicious in their use of tape noise reduction, and have left mono in mono and stereo in stereo, with no pseudo stereo or surround. If you are a Rolling Stones fan, go out and get some of these.