What's My Problem?

There was thread about passive preamp not long ago. Some made good points there. The purpose of have an active preamp is to have a more flat input/output resistance across the spectrum as well as input amplitude. This is more important than to provide gain, most of time you probably running pre-amp with <1 gain. For passive amp, you are changing input/output impedance while turn up or down the volume. You will get good result only when your CD player (output R) and power amp (input R) can still match the vaiation of your passive pre.

If you are not happy with the result, change it to a active preamp. Otherwises, you have to switch many CD players and power amp's to fit your passive amp. IMHO, you should get rid of bottle limited parts, not swap good parts to match your passive pre, 10 times effort and make not much sense.
Your players and power amp should not be a problem with normal active pre-amp.

When people tell you shorter path is better, you have to be careful about the statement. It is over-simplified and can be totally wrong in some cases.

Pat -

I'm not familiar enough with your speakers for this to be anything more than speculation, but here goes...

There's a nasty little thing that happens to most drivers called "compression". And, different drivers introduce different amounts of compression. There's a correlation between relatively high amounts of compression and low efficiency:

Suppose you take an 85 dB efficient woofer and double the input power, perhaps going from 1 watt to 2 watts. The output goes up by 3 dB, right? In theory yes, but not in practice. In this case, the driver's output only goes up by about 2.3 dB. The rest of that energy goes into heating up the voice coil and magnet structure. That .7 dB loss is compression.

Now let's say we have a 91 dB efficient tweeter. The compression will be less - with a doubling of power, we might get 2.7 dB (still not a full 3 dB, but closer).

Because of their differing compression characteristics, these two drivers will only match up at one loudness level. Let's say we pad the tweeter down so that, at 80 dB, the relative level of the two drivers is perfectly balanced. Down at 70 dB the woofer will be about 1.7 dB louder than the tweeter, so the tonal balance will be a tad dull on top. Down at 60 dB it's even worse - the woofer is 3.4 dB louder than the tweeter, so the speakers are duller and somewhat lacking in articulation. Going in the other direction, up at 90 dB the tweeter will be up by 1.7 dB, and the sound a bit forward and a bit bright. At 100 dB, the tweeter is up 3.4 dB, and the top end becomes a bit aggressive.

I don't know if this is what's happening in your situation, but it can happen in the real world.

Best of luck,

Duke

Audiokinesis --

That's really interesting . . . . could that explain why the 2.1s sound better than the 2.3As? The 2.1s have three identical 6-inch woofers and a tweeter, while the 2.3As have two identical 6-inch woofers, then a DIFFERENT midrange, then a tweeter. Seems like three different drivers would allow for more "mismatching" than two different types of drivers . . . . How do speaker manufacturers get around this issue?

Seandtaylor99 -- those are good ideas. I'll see if I can dig up an active preamp somewhere to try out. I don't think I want to experiment with running the 9000ES direct into the amp, since I don't think I have any CDs that are quiet enough for long enough to do a real test listen.

Bluefin -- Also good ideas. I think that if it DOES turn out to unquestionably be the passive that's the problem, I will swap preamps rather than trying to swap amplifiers and/or CDPs.

Marakanetz -- Thanks for the suggestions! I think I'd like to stay with NHTs, though, since my whole home theater is built with matched NHT speakers. The Creek would be an option, but that would be harder to integrate into the HT system than sticking with the Rotel amp I have (or another Rotel with more power) and changing preamps, if necessary.

Again, thanks to all!

Pat

Audiokinesis --

Disregard my last post. The 2.1s do, of course, have a midwoofer that is different from the two woofers. I was thinking of the fact that their mids are the same as the OTHER NHT speakers I have . . . .

Pat