What's My Problem?

Wow -- thanks for the great response!!

I've got some more info:

I had an idea that I SHOULD have had earlier, but didn't think of until I saw Warrenh's post mentioned changing amps OR SPEAKERS. Well, I have three other pairs of NHT speakers in my HT rig, all of which are 8 ohm and easier loads to drive than the 2.3As. I picked the 2.1s, which are full range and with almost the same driver complement as the 2.3As, but with a slightly shorter cabinet and an 8 ohm impedence.

I moved out the 2.3As and put the 2.1s in the same spot -- didn't tweak them, and the 2.1s don't have the NHT Spike Kit bars on the bottoms, either, but I figured it would give me an idea.

It did . . . .

The 2.1s absolutely blew the 2.3As away. The soundstage started big and got BIGGER as the volume increased, the harshness was noticeably decreased, and the bass was much more solid, in spite of the fact that the 2.3A is supposed to go lower . . . .

So I think we can safely say that the problem is some sort of issue with the Rotel driving the 2.3As. I'm going to play around some with your other suggestions, including going back to A/B through the Lexicon. Gs5556, I think the input impedence of the Rotel is 27K, although I am using 2 foot interconnects with a fairly low capacitance between both CDP/preamp and preamp/Rotel.

I'm going to be annoyed if it's the preamp . . . . just bought that, and I really like the sound (or lack thereof) with it in the system as opposed to the Lexicon . . . .

I'll keep everyone posted, and again, thanks VERY much for all the help!

Pat

Used Vandy 1b or 1c can be the same price as your new NHT but they can work great with weak and low-powered amps due to the stable impedance. Also for the vertually same amount of funds you can change for small Creek integrated to replace your separates that also has passive preamplification part and there you can start to listen to the music if you love one.

test #1.Could you connect the 9000ES directly to the Rotel power amp and play a not-too loud CD (even beter does the 9000es have a variable output ?).
test #2Alternatively borrow a friend's CD player with a variable output , connect directly to the rotel, and see if it sounds better than your preamp at higher levels.
test#3 borrow an active preamp and experiment.

If any of the above experiments produce the same over-aggressive sound then it might be that the amp is underpowered. Marakanetz was correct to point out that not all watts are the same (well, they are, but the way manufacturers measure them varies). Rotel is a bit of a middle-of-the-road manufacturer ... not at all bad, good value for money, but not all that great either.

If either or both of the above produce a loud, but not so aggressive sound then it would indicate that the preamp is the probably cause of the problems. I don't know why this might be, but it could be an impedance mismatch (since it's a passive pre). In this case switching to an active preamp might solve your problems.

I very much doubt the Sony CD player is the root of the problems.

Good luck.

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