Letters • August 2013

No Audio Research review

August 23, 2013


I'm surprised there is still no full review of the Audio Research Reference 10 and Reference Phono 10.

Rey Martirez

I've had my review sample of the Reference 10 for only a few weeks -- not enough time to finish listening to it, let alone write the review. But the review is coming, along with others, so stay tuned. -Marc Mickelson

A pair of subs for the CLX?

August 21, 2013


I presently own MartinLogan CLX loudspeakers and would like to add two subwoofers. My electronics are Conrad-Johnson ART amplifiers with ART 3 preamplifier. I have narrowed my choices to the MartinLogan Descent i or Eclipse TD725sw. I know that you have reviewed some of these products. Which pair would you recommend as an ideal match with my system and why?

Alain Cavener

Congratulations on having the independence and confidence to take the road less traveled! MartinLogan's CLX is one of the most underrated speakers on the market, a genuine high-end contender at a price that's almost approachable. As a bargain, it rates alongside the KEF Blade, and anybody who has read my KEF review will know just what a compliment that is.

The best 'Logan I have heard (by a country mile), the CLX is a definite member of my personal top-flight. I haven't heard the CLX in my new room, but it is definitely on the to-do list -- if only as an excuse to get the speakers back. One of the CLX's greatest strength is the space, speed and texture it brings to its low frequencies; they may not be the deepest but they are up there with the very, very best when it comes to portraying articulate, expressive and convincing bass playing that really breathes and throbs. But only after the speakers have been powered up for ten days. I'm sure you are aware of this, but many readers won't be. The CLX, whether because of the dual diaphragm construction or for some other reason, takes a full ten days to "charge," and during that period the bottom end fills out, gaining weight and extension, giving the speaker a body and presence that's a world away from (and significantly more authoritative than) the ethereal translucence that characterizes the "sound" of many electrostatics.

The end result is a speaker that is quick and transparent, yet presents images with solid presence and a superbly natural range of tonal colors. It's an impressive performance -- but one that is also a double-edged sword when it comes to matching it with subwoofers. When it comes to both positioning the CLX and integrating subs, it's crucial that the speakers are fully charged and remain that way. Never disconnect them from the AC supply when making system changes -- just disconnect the speaker leads or turn off the amplifier(s).

First things first. Your decision to use a pair of subs is spot on. The relatively limited lower range of the CLX means that spatial integrity and soundstage coherence (especially the stability of really deep instruments) will be much greater with a full stereo setup. Also, the two subs will mean that you have power to burn, allowing you the luxury of choosing how to deploy them. For ultimate extension you would position them differentially, exploiting the two principle bass modes in the room (one down, one across), but I would opt for slightly less power but the greater coherence and easier integration of a symmetrical placement. It looks neater too.

However, having said that, the final decision will depend on who is doing the setup. Let me explain. I have used the Eclipse subs with great success, their force-canceling driver arrangement and labyrinth construction delivering the taut, clean and quick low frequencies that are necessary to integrate properly with the single-driver, crossoverless Eclipse satellites. Played in mono, it is a construction that becomes even more effective as both drivers receive identical signals. I have never used the MartinLogan Descents, but these share the force-canceling feature of the Eclipse, and it's hard to argue with 'Logan's experience in the field. Neither design depends on the potentially ruinous option of digital room compensation, with its attendant risk of musically destructive latency, thus side-stepping that possible pitfall.

Given that both units are capable of excellent results, the deciding factor will be set up, always a super-critical consideration when it comes to the successful integration of subs into really high-quality systems. The secret of using subs, the same as for any audio system, is that the whole must be greater than the sum of the parts; you are aiming for better, not just more. How often have you heard systems that sound better with the sub(s) off? All that cost and complexity, and if you get it wrong, they just mess things up. The simple fact is that somebody who really knows what they are doing, working with even a basic sub, will achieve far better integration and more musical results than a beginner playing with the best sub in the world.

So, which subs you buy will depend on who is going to install them -- and the strategy adopted should be chosen by the installer too. If the choice rests between a local purchase from a capable dealer and a remote purchase, go local; you won't regret it. When it comes to integrating subs and actually realizing their considerable potential, experience is everything. So which dealer offers the best performance and expertise? It is the dealer you are choosing here. By now, you will probably know the answer to that question, but if you have no local Eclipse dealer, then opt for the Descent. If you have no local Eclipse or MartinLogan dealer, then ask the companies for advice -- not just for the closest dealer but the one who will do the best job for your situation. Otherwise you risk not just wasting the investment in the subs, but potentially damaging the results you are already achieving from the CLX.

However, get it right and heaven beckons; as good as the CLX is, properly integrated deep bass will take the speakers to another level. Achieve that goal and you'll end up with a superbly capable and musical speaker system that's more than worth all the effort and expense invested. Although we tend to focus on the selection of equipment, often spending hours agonizing over the choice of one unit as opposed to another, in this case success will depend less on the selection of the subs than the person who installs them. The old adage, "It's not what you use, it's the way that you use it" is always relevant to audio, but never more so than when it comes to subwoofers. Enjoy the journey and I'm sure that you will enjoy the results. -Roy Gregory

New amp or new speakers?

August 14, 2013


I would appreciate your advice concerning a compatibility issue relating to my current setup. For the reasons explained below, I think I may need to either go with a high-current solid-state amp or switch out the Paradigm Signature S8 v3s for more tube-friendly speakers.

As of late, I have been experiencing listener fatigue while listening to my Paradigm S8 v3 speakers, which are being driven by an Audio Research VS-115 tube amp. All of my electronic gear is Audio Research tube. At times, I've found the acoustic presentation to be bright, even forward. I think I know why.

I’ve been doing a bunch of reading and e-mailing to/from a number of the "EE/tech geeks" online. I think I have an idea about what the problem may be. The “geeks” suggested driving the S8s from the 4-ohm taps, which I did. Something still doesn’t sound quite right. More back and forth with my fellow hobbyists and the issue of the S8s' impedance characteristics came up. As you may know, the S8s are nominally rated at 8 ohms. In fact, a lab report on the S8 v2 shows that it has some pretty wild impedance curves: 4 ohms below 700Hz, then rising sharply to 28 ohms at 2.2kHz (crossover point), and then declining to about 6 ohms as frequency response increases to 10-15kHz. The phase angles in the low bass are quite reactive, around negative 60 degrees.

The techies postulated that my amp would have problems getting good tight bass out of the S8s and could sound bright in the midrange because of the impedance spike. I called the Paradigm tech folks and asked them if the S8s were voiced to be driven by a solid-state amp. They said yes, one that can deliver high current, like their Anthem P2. Incidentally, I reread your May 28, 2010 review. As I recall, you alluded to driving your test S8s with a set of top-of-the-line Ayre monoblocks.

A former tax colleague of mine often used the expression, when one of the junior kids would mix up tax concepts, "You’re trying to mate an anteater with an elephant." It just may be that the S8s are not tube friendly, period.

So, there’s my dilemma and the reason I am asking for your advice. If you think I would do better to switch out my tube amp for a solid-state amp, what do you think about the Ayre VS5e series, which generates 150 watts into 8 ohms and a lot more into 4 ohms, with zero negative feedback? Or, keep the VS-115 and ditch the S8s? If the latter, I hate to ask what is a really good, tube-friendly speaker because there must be a thousand speakers on the market and it’s not possible or practical to audition very many.

Bruce Feinstein

I once experienced what you describe as "listener fatigue" long ago, with Thiel CS3.6es, which were a tough load even for some solid-state amps. While I was able to tame this with a tube amp whose high output impedance shelved down the CS3.6's treble, I discovered long after the fact that sitting too close to the speakers exacerbated the problem, so the drivers were sounding like discrete entities and not summing. The tweeter especially stood out.

So my first suggestion would be to move your speakers -- forward, backward, left, and right. Toe them in more and less, and try changing their rake angle -- using the spikes or some spacers to tilt them forward and back a small amount (not enough that they fall over). If this doesn't solve the issue, it could be that the S8 v3's impedance is such that the Audio Research tube amp, even from its 4-ohm taps, is not able to drive the speakers down low with the same ease it does elsewhere, creating an imbalance in the sound that leans toward the upper midrange and treble. My experience with Audio Research tube amps is that their output impedance is low enough for this not to happen very often, but I suppose it could be possible here.

Providing that the problem persists, your easiest solution is auditioning a few solid-state amps, and the Ayre is a good one with which to start, given my success with the MX-Rs and the S8 v3s. Beyond that, if your budget allows, you might want to try some Lamm M1.2s, which are hybrid designs that will surely drive the speakers well and without issue. I don't have any experience with Anthem amps, but I understand that the company's M1 monoblocks are supposed to be somewhat soft-sounding up top, which may make for a satisfactory outcome with your speakers.

As for different speakers, the various Wilson Audio models, including the Sophia 3, are great matches with Audio Research tube equipment. I also like the various ProAc speakers I've heard (and owned) over the years, and they again match very well with Audio Research electronics. I think you'll end up paying quite a bit more money than the cost of your S8 v3s if you go either route. A competitive option in terms of price is the Magnepan 3.7 (or even the 1.7, which is an amazing speaker and value), which is not a sensitive speaker but is a uniform load that your tube amp will drive without issue. -Marc Mickelson

Joining the reader list

August 9, 2013


Please add me to your reader e-mail list.

Rob Isakson

Joining the reader list is easy. Just send e-mail to rl@theaudiobeat.com. After you join, you will receive notices of all new content on TAB. -Marc Mickelson

". . .I owe this to your review"

August 5, 2013


I realize that in writing you yet again I run the very real risk of becoming a nuisance. I sincerely hope that is not the case. I write you because I had one of those "Ah ha!" moments today that I hope you will find not only amusing but also gratifying.

I was listening to music when I noticed that things just did not sound right. The center image was not exactly in the center and both the left and right channels sounded like everything originated from the KEF Blades' Uni-Q drivers. I knew this was not right. I had programmed the Aurender to play a wide variety of music at random. A song started that I didn't particularly like, so I reached for the iPad on the coffee table to change selections. I suddenly noticed that the soundstage miraculously improved. To be sure it was not my imagination, I leaned forward and back several times, and sure enough I was not hearing things.

I then remembered your Blade review and the comments concerning rake angle. After some adjustments to the two rear Stillpoints on each speaker, the bubble level showed that the speakers were tilted forward just slightly. After this adjustment, the soundstage was now remarkable. The center image was precisely in the center and the left and right channels were just "there" and not originating specifically from either driver. Best of all, for the first time ever, I now had a soundstage outside both speakers. Unless somebody convinces me differently, I'm not moving the Blades again. They are now set.

I feel I owe this to your review. Nowhere on the KEF website, or in any other Blade review I read, or any of the information that accompanied the speakers were there any comments regarding rake angle. In fact, if memory serves, KEF recommended that the speakers be dead set vertical. So yet again your findings proved correct.

Paul W. Fleek

Cambridge Audio and Rega: the best from both?

August 1, 2013


Well, my Cambridge Audio Azur 840C has something going on with the laser assembly -- it needs repair. That being said, I pulled my Rega Apollo out of the bullpen. I remembered then that the Cambridge unit has a digital input, so I decided to use the Rega as a transport and  still be able to utilize the DACs in the Cambridge.

My question is, by utilizing only the DAC portion of the Cambridge am I technically getting the sonic attributes of it? Maybe I'm getting the best from both units this way. It certainly saves some money over having the Cambridge repaired.

Sheldon Simon

You are definitely hearing the Cambridge DAC when you connect your Rega Apollo player to its digital input. However, the S/PDIF interface between the two is also adding jitter to the digital stream, so you're also getting some sonic degradation. Your Cambridge and Rega units could make up for this to some extent, if the Cambridge rejects jitter effectively and the Rega is a superior transport to begin with. One way to maximize this arrangement is to find a used Genesis Digital Lens and insert it between the two units (you'll need an extra digital cable as well). This nondescript black box is a sophisticated jitter-reduction device that reclocks digital data in a RAM buffer. It also strips out subcode information and adds dither to the digital signal. The Lens is very effective, and there's still nothing like it on the market today. It cost $1800 new nearly twenty years ago, but you can find them used for around $400, although they are not abundant. While it is worth every penny -- if you can find one -- that money might be better spent having your Cambridge player fixed. -Marc Mickelson


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