November 2011

Audiolics Anonymous Chapter 144
JL Audio Fathom F 113 powered subwoofers and my system redo.
Article By Bill Gaw

  Welcome to the completion article for my twelfth year of ruminations for this web rag. Back then, I was asked by our illustrious editor Steven R. Rochlin to write one column about my system after he had come over for a listen and to meet the late, great engineer Allen Wright, who had just brought over from Munich a pair of specially built preamps. Either he heard something he liked or, he needed to fill pages in his magazine and was desperate for writers (Steven sez, i heard your system Dr. Bill and it sounded truly amazing!). Prior to that time I had been soaking up knowledge from my gurus, such as Clark Johnsen of Wood Effect fame, the late great Sal Demicco, Either way, that single column has grown to 144, hopefully none of them redundant, except of course for my diatribes on the crappy electricity we all suffer with. Anyway, it is 12 years and counting.

Now on to something of value, Fall cleaning of our systems. Like ourselves, our systems do age and need maintenance from time to time. Phono bearings need oiling, cartridge styli need cleaning, speaker drivers need dusting and tightening of their cabinet screws, all connections oxidize and need cleaning and possibly coating, tubes need replacing or testing and equipment chassis need dusting, as discussed at this link. Last time this was done with my system was two years ago, although in the past it was done on an annual basis, just before winter listening season, but my tired old bones (and muscles and joints and everything else that aches on a 64 year old) have cried out each time I've recently thought about it.

The incentive to do some cleaning this year was the arrival of a new set of subwoofers, which will be discussed below. While I love the sound of my system, being a typical audiophile, there's always something gnawing at your gut over some imperfection. Mine has always been the deep bass. While the room is supposedly built to audiophile standards, from day one there's been a problem with the bass not being where it's supposed to be. Believe it or not, the best place to hear bass from my media room is in a shower built next to it, or our bedroom above and behind it.

In the room with my present setup, the bass, while deep and full, has always been a little loose, not punchy, with a peak in the 30 to 40 Hz range. I've done everything from using the built in Audyssey equalizer in my pre-pro, to doing a 24 dB crossover at 20 Hz. for the subwoofer to doing a 48 dB crossover on my woofer, all of which either worsened or changed the problem. The gnawing finally got to the point where I decided to go ahead and purchase a pair of store-bought subwoofers for my main speakers and use the white self-built subs seen below as my video subwoofer channel.

So what was the end result of all of this back-breaking work, and was it worth it. In two words, a phenomenal improvement! The soundstage tightened and the central image solidified, probably from the equipment rack removal. The bass, while only going down to the mid 50's with the horn woofer, was less lumpy. The midrange also improved, possibly due to the connection cleaning, and on my best recordings, there was more there, there.

The first drawback was a slight foreshortening of the depth, which I was happy to allow considering the rest of the soundstage improvements. Second drawback was an increase in tape and microphone hiss, even on digital recordings, again probably due to more information coming through. All in all, a well spent four days. I just wish my wife thought so, as her holiday weekend was wasted. TOO BAD!!

What was missing? The deep bass as the 6 foot long horn woofers only go down to the mid 50's with a natural 12 dB per octave roll-off, about the same range as a mini-monitor. This is where the new subwoofers come in. As this was the main weakness in my system, and I felt that my self-built sub's just weren't hacking it, I've been looking at reviews for a couple of years on the many subwoofers available in all price ranges and found one company that has had nothing but outstanding comments from several reviewers that I trust (even several from other magazines).

Then I had to decide on configuration. Should it be one very large mono unit that could cover all of the front speakers, or a smaller stereo pair which could help with imaging, but be somewhat more expensive. The audiophile side of my brain won out over the Scot side, and two were decided on. Since I had several subs to cover the subwoofer channel for my video, spread out around the room to decrease problems with room reflections, I didn't need a mega-sized mega-priced unit. The advertising people for the company I decided on were contacted through my Fearless Leader, Steven R. Rochlin, and within two weeks two very large and extremely heavy ( over 130 lbs. each) boxes on a wooden pallet were delivered by Fedex Freight, unhappily left in front of my garage from where I would have to move them myself, the…

JL Audio Fathom F 113 Powered Subwoofers
JL Audio, based in Florida, originally and still producing drivers, speakers and amplifiers for car and marine use. But they took their knowledge on producing bass in tight places and started producing home audio-video subwoofer systems. At $2100 for their F110 to $12,000 for their Gotham G213, and $3600 each for the two F113 units I ordered, they're not inexpensive, but certainly fall within the normal price range for high end subs.

Each 19x16x19 inch cube contains a 13" driver, 2500 watt amplifier, 12 or 24 dB crossover, microphone and equalization circuit, weighs 130 pounds and has both single ended and balanced connections. Each comes with a thick IEC AC cord and a special measuring microphone with cable and pouch and even a set of cloth gloves so that our greasy hands don't mar the satin black finish. Being a sealed enclosure woofer, the frequency response is -3 dB at 18 Hz. and only -10 dB at 16 Hz, so even that bass note in second and last movement of the Saint Saens Third Symphony should be evident. It has a defeatable volume control, and polarity and phase adjustments to exactly mate it with the main speakers.

Setup, per their instructions, is intuitive, although backbreaking due to their weight as they are supposed to be moved around the room to find the best spot. The directions suggest that you place it in the room so that its output matches with the main speaker in an area that creates the fewest standing waves for the listening seat. As I wanted to time align it with my horns, my units were placed right next to the woofer driver chambers. Rather than using the built-in crossover, I set my Marchand XM9 unit for low and high pass at 60 Hz., just slightly above the cutoff frequency of the horns, reversed the polarity of the Fathom, played a 60 Hz. note and nulled out the volume to get a starting point for the sub's relative loudness, then reversed the polarity switch to mate it with the woofer. Luckily since the two speakers were together, there was no necessity to adjust the phase control.

Next, the microphone was attached and the room optimization procedure was begun. The unit has a one pole equalizer that will null out the worst peak in its frequency range. One minor problem in my room was that during the setup, with the volume control set at 3:00 it was too soft and at 3:15 too loud, but finally setting it at 3:10 allowed the unit to run through frequency sweeps at various levels from merely slightly annoying to bowel exciting.

This sequence brought out a major problem; various frequencies brought out sympathetic vibrations throughout the room which have never occurred before, and my wife, less than overcome with joy from her lost weekend and fresh from her weekly allergy shots which do not improve her disposition, slammed the room door shut which screwed up the measurement. Guess I'll be battening down the hatches in the next few days. Thank God this only had to be done a second time for one speaker and once for the other.

Remarkably, after these two adjustments, the bass was the best I've ever heard from this system, and just about any other I've evaluated except for Romy the Cat's system in his new house, and what Clark Johnsen used to be able to produce in his 30x50x20 foot Listening Studio years ago. It was tight, deep and fast (I know, bass isn't supposed to be fast. What I mean is that the internal amp had such control over the driver that the bass didn't just pressurize the room but could produce a compression wave with bass drum and tympani similar to what one experiences at live performances And yes, the 16 Hz. Saint Saens Third note came through at realistic levels.

With certain recordings, the environment's low frequency information makes the original concert hall pressure feeling come out. On early RCA recordings from one English concert hall, the sounds of the several subway tunnels crisscrossing under the hall comes through loud and clear, and with the two subs, one can actually hear which direction the trains are moving. On recordings of the BSO done in Symphony Hall in Boston, one can hear the traffic from the right speaker emanating from Massachusetts Avenue, something I haven't heard here since my 6 foot tall VMPS Super IIaR's with two 15", three 12" and four 5" drivers, were replaced 20 some years ago. I know, that's not the music being reproduced but the effect of hearing the ancillary noise, including the older heating systems that naturally occurs in halls ads tremendously to the perception of a live event.

But what is really remarkable is how it has melded with and freed the bass horn from having to produce the ultra-low frequencies, which has cleaned up the upper bass and lower midrange, giving an increased clarity to the image, while filling the soundstage and the front half of the concert hall with the naturally occurring low frequency noise that allows us to feel we're in a real space.

One doesn't know how much better one's system can sound until one hears the difference, and then there's no going back. Guess the subs will be staying in my system. I just hope my wife will be staying also when she finds out they're not leaving, and what they're costing. Oh well, such is the life of a married audiophile. Maybe that's why so many of us are single.