Reb1208: Everything that you posted was VERY good info. Having said that, using such an approach is what one has to do when working to "band-aid" deficiencies in the system.
1) The lighter gauge wire will tend to reduce low frequency output and open up the top end, in effect, helping to even out the tonal balance.
2) Using one set of cabling rather than bi-wiring may increase coherency from top to bottom. Using two sets of different cabling can sometimes skew tonal balance and coherency.
3) While "sturdy" amps should be "mandatory" for most installations, it is pretty much required for an installation like this. Your Suggestion of Classe' also seems reasonable so long as one doesn't go too high in their model structure. The lower models tend to sound leaner in bottom end and brighter up top, making them a more suitable candidate. Their upper models have a noticeable high frequency droop, which would only aggravate the problem. All of their models are typically "sturdy" in terms of current capacity though.
4) "Light & airy" would be a good descriptive term that i overlooked. Added brightness typically accompanies "hardness" in the upper mids. Personally, i find a lot of the Musical Fidelity gear to sound "light & airy". While i don't think that their amps would be a suitable choice for this installation, their digital gear or possibly a preamp might work great.
5) Moving the speakers further out in the room will reduce low frequency reinforcement. Tilting them back will elevate the angle of radiation from the tweeter, bringing it more in line with one's ears at seated listening height.
and this one wasn't mentioned, but...
6) Install additional amounts of polyester fiberfil into the cabinet. This will help reduce the bass hump in amplitude. One can vary the density and quantity of stuffing to suit their specific likes / dislikes in the low frequency department. 20 ounce bags of polyester fiberfil can be purchased at Wal-Mart for under $2. These are located in the "arts & crafts" section.
Bravo to you for working through the challenges that this speaker presents. With that in mind, wouldn't it have been easier to build your system around speakers that were a little more neutral in response / didn't require so much "band-aiding" ?
Dave: The Sunfire amps, especially the Signature's, do quite well with multiple large woofer arrays and / or speakers that are of a lower impedance. That has to do with two specific design attributes of these models.
The first is that they are very powerful amplifiers. They utilize high rail voltages and can produce very high amounts of current. That is why they REALLY "double down" as impedances are halved. As i've mentioned before, "doubling down" is a way for the manufacturer to play with numbers and make the amp appear to have more "audiophile appeal". Where the Sunfire's differ from other amps is that they don't just double down in terms of RMS power rating, they come very close to doing this at the point of clipping. Most amps don't come anywhere near "doubling down" when driven to clipping. Since clipping puts a strain on EVERY part of the amp, seeing what an amp can do at these levels into different impedances is a great test of an amps "intestinal fortitude".
The high rail voltages that the Sunfire's produce is needed to deal with the reflected EMF ( electrical back pressure ) from larger woofers. The high current capacity helps deal with the low impedance issues. Current is what controls the forward motion of the driver and the higher rail voltage helps to damp the inward thrust of the cone. Due to multiple woofers, you need a LOT of current due to the lower impedance AND a LOT of voltage due to the higher levels of reflected EMF ( Electro-Motive Force ). If you lack one or the other, you'll end up with sonic deficiencies.
The second factor is that the Sunfire amps are very efficient and run reasonably cool under most loads. This is one of the reasons that they sound less strained at high volumes and can maintain coherency in a more consistent manner. The wider the temperature swing that an amp goes through, the more likely that the amp will be to vary sonically during those swings. High bias amps get around this ( once fully warmed up ) by staying quite warm all the time. If you turn them off, they have to thermally stabilize all over again and the sonics will suffer until they do. In my experience, this can take quite a long period of time to do so and it is the reason that i recommend leaving high bias amps powered up all the time.
High efficiency amps ( like the Sunfire ) tend to offer less thermal variations, therefore presenting a more consistent sonic presentation when going from stone cold to normal operating temperature. While they do change their sound somewhat as they warm up, the difference is not nearly as drastic as it is with higher bias designs. A good 20 - 30 minute work-out session is all that many of these types of amps need to "limber up" and operate at peak sonic levels.
Having said that, my thoughts are that a well designed high bias amp that is thermally stable will typically sound better ( at least at low to medium levels ) than a low bias high efficiency design. When you start throttling the amps hard, the low bias high efficiency amplifier designs may have some advantages. This is especially true if you like to "raise the roof" for extended periods of time.
As with your specific situation, the Legacy's have three good sized woofers and are of lower impedance. Due to the fact that you like to "rock", you also probably tend to listen at a higher average level than what someone listening to Classical or Jazz tends to. In effect, the Sunfire ( and especially the Sun Sig ) were built for speakers / systems / listeners just like your situation called for. I can see how you think that the Levinson is a step backwards, because in your case, it probably was. Had i known that you had a Sunfire Signature, i would could have explained why this was a good combo. Having found out after the fact, i can only mention this in retrospect.
As a side note, my Father has been using Legacy's in stock form for many years. After trying well over a half dozen different amps with his speakers, the best match was with Sunfire products. The second best was with some older Nelson Pass built & designed amps. These sounded more articulate and "sweeter" than the Sunfire, but couldn't deliver the bass control or output that the Sunfire's did. Since doing these comparisons, i have modified the Legacy's for drastically improved performance and think that the older Pass designs might feel more at home than they did before. None the less, my Father is happier with his system now than he has ever been. Then again, i've replaced every piece of gear ( cables included ) that he had with units that i selected for him. The only units that are remaining ( his speakers ) have been highly modified. With all of the drawbacks to having me as a son, i guess that there are a few benefits too : )
As a general comment, you folks have to be careful when buying gear. One has to look at the "BIG picture" when building a system, otherwise you end up with components that are not a good match electrically or acoustically. Buying "audiophile approved" name brands and / or spending more money isn't necessarily going to get you better results or the specific results that you are looking for.
This is one of the major reasons that i try to encourage others to read and learn as much as you can about spec's and how products work / are designed. The more that you know, the more informed your purchasing decisions will be. The more qualified your purchases are, the more likely you are to achieve good sonics with the specific results that you are looking for. Building a system properly uses quite a bit of science. If you don't know your science i.e. how to interpret spec's* accurately, it becomes more of an "art". Much of that art comes into play trying to balance the deficiencies ( band-aiding colourations ) that one could have avoided if they knew their science. Sean
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* When it comes to interpreting spec's, the spec's that you are looking at have to be taken under real conditions and documented in a usable manner. Otherwise, inaccurate spec's make for inaccurate comparisons. On top of that accurate spec's using non-standard rating systems make it very hard to compare values with other units that use industry standard rating systems.
Some manufacturers do the former ( pumping up spec's ) while others do the latter. The reason that they do the latter is so that they can say that they did provide spec's / have nothing to hide, but at the same time, the average enthusiast doesn't know how to convert those spec's to something usable. If they did, they would know that the unit wasn't as good as they thought. That's why the manufacturer gives you only "half-truths" i.e. spec's that aren't usable for sake of comparison.
