Correct tap 2 or 4 Ohm for the 1,7 Ohm curve

[tom1120s]

Bi-wire.

4ohm tap for the bass and 8 ohm tap for the mids/highs. Yes, you can do this plus I bet the speakers will sound better than if you just used the 4 ohm tap for everything.

Those are very capable amps so I think the 4 ohm tap will suffice for the lows.

[rob725]

I did this in reverse going from 1.25s to xrt1.1s when I first got them. Initially they were a bit bright, so by hooking the mid/high panel to the 4ohm, it reduced it 3db relative to the midbass/sub portion of the xrt's. As they broke in, I went back to the 8ohm tap for all.

[damacman]

Originally Posted by cleeds

That is not quite accurate. Heat is a byproduct of inefficiency, right? After all, a perfectly efficient amplifier would produce no heat.

An inefficient Class A amplifier will produce heat even at idle. As it required to produce more power, it will produce the same amount of heat, so it is not correct to state that as power increases, "more heat is wasted as result of efficiency losses."

Well we're not talking about Class A amps here ...nor 100% efficient amps. Class AB amps average 60% efficiency. It just happens that 1/3 power is the point at which power supply and output devices generate the most heat collectively.

[dag johnsen]

Originally Posted by rob725

I did this in reverse going from 1.25s to xrt1.1s when I first got them. Initially they were a bit bright, so by hooking the mid/high panel to the 4ohm, it reduced it 3db relative to the midbass/sub portion of the xrt's. As they broke in, I went back to the 8ohm tap for all.

Hi,

would you say the 1.1 are more bright than the 2.1?
Do you have to use subwoofers with the 1.1?
I have heard the 2.1 but not the 1.1.

Dag

[rob725]

Dag,

I've not heard 2.1's, but looking at the driver make-up, they may be. The 2.1s handle below 150hz with 6 8" woofers vs the 1.1 using 4 6.5". Yet, they both use 2 6.5" drivers for mid-bass. Also, the 1.1s crossover to the high-frequency panel sooner at 400hz vs. 450hz for the 2.1s. Then, the 1.1s use 24 2" midrange and 40 3/4" tweeters vs. 28 & 45 for the 2.1s. Given that the panel is larger on the 2.1s, I'm goings to guess that the high frequency drivers are more spread out on the 2.1s. Given all of that, it would not be surprising if the balance tilted hotter on the 1.1s.

Unless you really want authoritative bass at or below 20hz, the 1.1s do not need a subwoofer; I don't use mine for two-channel. Using testing recordings, I can hear 20hz, but it's not real loud. I did have to go around my room fixing light fixtures, aircon return grates, projector screen housing, because the 1.1s had no problem rattling the room 25-80 hz. The 2.1s must be incredible down low.

Using the crossover on the 901's I currently attenuate the panel about 1.5db. I say currently because they have consistently improved in this regard. Switching to the tubes on the 901s helped, cabling, esp. power, has helped and all of the components, including the 1.1s, breaking in has helped smooth everything out. It just keeps getting better. What this means in practical terms is I can both turn it down lower for normal listening and turn it up higher for incredible slam.

[Charles]

Originally Posted by rob725

Dag,

I've not heard 2.1's, but looking at the driver make-up, they may be. The 2.1s handle below 150hz with 6 8" woofers vs the 1.1 using 4 6.5". Yet, they both use 2 6.5" drivers for mid-bass. Also, the 1.1s crossover to the high-frequency panel sooner at 400hz vs. 450hz for the 2.1s. Then, the 1.1s use 24 2" midrange and 40 3/4" tweeters vs. 28 & 45 for the 2.1s. Given that the panel is larger on the 2.1s, I'm goings to guess that the high frequency drivers are more spread out on the 2.1s. Given all of that, it would not be surprising if the balance tilted hotter on the 1.1s.

Unless you really want authoritative bass at or below 20hz, the 1.1s do not need a subwoofer; I don't use mine for two-channel. Using testing recordings, I can hear 20hz, but it's not real loud. I did have to go around my room fixing light fixtures, aircon return grates, projector screen housing, because the 1.1s had no problem rattling the room 25-80 hz. The 2.1s must be incredible down low.

Using the crossover on the 901's I currently attenuate the panel about 1.5db. I say currently because they have consistently improved in this regard. Switching to the tubes on the 901s helped, cabling, esp. power, has helped and all of the components, including the 1.1s, breaking in has helped smooth everything out. It just keeps getting better. What this means in practical terms is I can both turn it down lower for normal listening and turn it up higher for incredible slam.

I think it incredible Mac can get the type bass response you are describing from 6.5" drivers.

[rob725]

Well, 4 x 6.5 is similar surface area to Gotham's 2 x 13.5. They are long throw as well. I was going to play with bringing the Gotham's in somewhere between 40 an 50 hz.; even got the JL crossover which is pretty cool as it will let HT pre/pro signal bypass the two-channel set-up when watching movies. I figured it would relieve the small drivers from handling the deepest bass. Unfortunately, I couldn't get the cabling through. I may try it in the future if I ever take the lid of the stage (I have some other cables I'd like to run), but for now I've no complaints with the bass at all. If I had the patience to move them around, I imagine I could even find a more optimum location for the bass. They are not trivial to move, but still much easier than the nearly twice as heavy 2.1s.

That's the problem with this affliction...I mean hobby; no matter how good it sounds, I can't help but think of ways it might sound even better.

[Charles]

Originally Posted by rob725

Well, 4 x 6.5 is similar surface area to Gotham's 2 x 13.5. They are long throw as well. I was going to play with bringing the Gotham's in somewhere between 40 an 50 hz.; even got the JL crossover which is pretty cool as it will let HT pre/pro signal bypass the two-channel set-up when watching movies. I figured it would relieve the small drivers from handling the deepest bass. Unfortunately, I couldn't get the cabling through. I may try it in the future if I ever take the lid of the stage (I have some other cables I'd like to run), but for now I've no complaints with the bass at all. If I had the patience to move them around, I imagine I could even find a more optimum location for the bass. They are not trivial to move, but still much easier than the nearly twice as heavy 2.1s.

That's the problem with this affliction...I mean hobby; no matter how good it sounds, I can't help but think of ways it might sound even better.

Also, there's a lot of psychology with bass. When you have large woofers and material that is light on bass you may not tend to like it as much with you might with smaller woofers. I also think smaller woofers provide inherently tighter bass than larger woofers. I think what Mac has accomplished with the 1.1 and 2.1 is pretty incredible. I can't imagine the bass power of a 2.1.

Charles

[damacman]

Well, simple math shows that a 13.5" diameter driver displaces 4.3x the area of a 6.5" driver. When you factor the massive delta in excursion capability of the JL driver and a comparison is made between Volumetric Displacement (Vd) of each, it may take a dozen or more of the 6.5" drivers to equal it.

Multiple smaller drivers working together lever a phenomenon called mutual coupling. This is akin to two cars traveling faster than one in NASCAR by the rear car drafting the first and splitting the wind resistance. However, in order for mutual coupling to be maximized, drivers must be mounted as near as possible to one another.

Smaller vs larger is a personal preference. I like both when executed well.

[Charles]

Originally Posted by damacman

Well, simple math shows that a 13.5" diameter driver displaces 4.3x the area of a 6.5" driver. When you factor the massive delta in excursion capability of the JL driver and a comparison is made between Volumetric Displacement (Vd) of each, it may take a dozen or more of the 6.5" drivers to equal it.

Multiple smaller drivers working together lever a phenomenon called mutual coupling. This is akin to two cars traveling faster than one in NASCAR by the rear car drafting the first and splitting the wind resistance. However, in order for mutual coupling to be maximized, drivers must be mounted as near as possible to one another.

Smaller vs larger is a personal preference. I like both when executed well.

I think you are correct in your assessment but there is much about achieving powerful deep bass that I have never understood. This is very obvious when you consider the 1.1. All things considered when you have smaller woofers, they can be faster than a larger woofer thus producing better tighter bass.