Comments, please, on Spica TC-60 setup.

Lowering the TC-60s eliminated the bass resonance. Replaced the 26" stands with 16" cinder blocks. I think the resonance was caused by the height (26") being too similar to the distances from the side walls (27") and the front wall (33"). My chair is very low, but the cinder blocks are still about 3" too short. Will eventually replace them with 18"-20" stands. Thinking of VTI RF 19".

Currently no sub in use. Tried a Mission 700AS sub using high-level pass-through connections, but it sapped the imaging and didn't integrate well. Now debating whether to add an active crossover or just sell the sub. Will add Straightwire cables & interconnects (found a great deal) soon to replace my cheap Monster stuff.

Soundstaging & imaging are now terrific. Bass is smooth, but slightly muddy compared to my friend's Brentworth Type IIIs. Lower midrange is a tad warmer than I'd like on vocals, but very nice on the right recordings. Treble is detailed and smooth, but not airy. Overall, pretty amazing for a <$1,000 speaker. Imaging is in the same league with some good $3,000 speakers.

Interestingly, I can adjust the soundstage for big sound (Lyle Lovett, Manhattan Transfer, Dire Straits) and intimate sound (Miles Davis, Boz Scaggs) simply by moving my chair front-back by about one foot: closer for big and farther for intimate. No need to move the speakers.

I have owned a pair of Spica TC-50's since 1988 and they were my main speakers until 1994. I used it with a Forte model 3. A really good amplifier will really make Spicas sing. I have heard the TC-50's with everything from a little NAD 3130 (30wpc) $200(new) to the mighty Threshold SA4e (100wpc pure class A, $6300 in 1989). The better the front end, the better the results with the Spicas. The little TC-50 mated with the SA-4e produced some of the best sounds I have ever heard in hi end audio. No kidding. Of course NOBODY would ever mate a $550 speaker with a $6300 amplifier but it did sound totally awesome. I also auditioned the TC-50's with the Threshold S/200, Forte'1a, Forte'3, Aragon 4004, and NAD 2600 amplifiers and the TC-50 is transparent enough to display the vast differences in the sonic signatures of the various amplifiers. You might try finding an old Forte'model 1A or model 3. They mate really well with the Spicas and really make them come alive. I am not certain which subs will mate well with the TC-60 but the TC-50 did well with the Vandersteen 2W. You will need separate amp and preamp to utilize the 2W because it utilizes a passive line level crossover.

Here's my theory on mating smallish ported speakers like the TC-60 with a sub(s).

1st part of the problem - if you're running the speaker level output from your receiver through the sub's crossover then into the Spicas, you have probably already scrambled the phase of even the high-passed signal. So the whole advantage of the TC-60's design is out the window.

2nd part of the problem is that the TC-60's port will still create it's "one note" bass even with the main speakers crossed over to the sub above the port's tuned resonance. The port output interacts with the sub's output and creates a hump in the bass response and mud.

3rd part of the problem is that to get full benefit, you need to crossover at a fairly high frequency since, without the ports reinforcement, the speakers just don't go all that low. So the sub drivers have to be small enough to accurately produce at THEIR higher end. And if you crossover high up - imaging from the sub becomes an issue. So basically, two 10" subs are better than one 12" or 15".

To attempt a solution -
Try this - pack an old tee shirt loosely all the way into each of the TC-60's ports. You don't want to seal the speaker airtight - you just want to interfere with and dissipate the bass response of the port itself. This will allow the sub to do it's thing without interference, and will improve the imaging from the mains.

If this isn't how you were doing it - Run the sub directly from the receiver's subwoofer outputs while running the speakers from the receiver's normal speaker outs. Experiment with setting the sub's internal crossover on the higher or lower points (which are both pretty high on the Mission, anyway).

Make sure that the sub is EXACTLY centered between the speakers AND the same DISTANCE from you as the Spica's midrange drivers.

If this works pretty well, consider adding a 2nd sub in a stereo configuration.

I haven't tried this with TC-60's specifically, but it has worked well on other ported designs I have played around with.

I used TC-50s for years (still have them in fact, although I no longer use them). Spicas were notorious for their small "sweet spot." If you're sitting in the sweet spot the Spicas have incredible imaging and clear mids, but I could hear the imaging collapse if I moved my head 2 inches. Peter Moncrief compared the Spicas to a Nikon camera lens which requires more fiddly, careful focusing than the lens in a cheap Kodak. The Kodak is easier to use but gives much poorer results than the Nikon. Anyway, I found that I had to position the TC-50s so that the bottom of the tweeter opening in the felt blanket was aimed precisely at my ear, and that the speakers were toed - in so that imaginary beams coming out of them intersected about where my head was. I'm 6' 2" tall, so to get the TC-50s' tweeter aimed at my ear meant either an impractically tall stand or tilting the speaker back. I made some tall spikes that allowed me to lift the front of the speakers about an inch above the stand. I even used strings taped to the front of the speakers to insure that the speakers were aimed correctly (I'd use a laser now). Lastly, in my experience the Spicas benefit from some bass reinforcement from being placed relatively close to a wall.

Opalchip and Robdoorack - thanks for the feedback.

Opal - I've ditched the receiver and now have an Adcom GFP-555 and two GFA-5200s and am running the Spicas biamped & biwired. Way more power than I could ever use without getting evicted. The volume control never gets past 10 o'clock. The GFAs drive a 4-Ohm load easily, and the TC-60s are nominally 6 Ohms.

1st part: You're right. I suspected the sub's built-in crossover might scramble the imaging, and it did. Hence the interest in an active crossover between the preamp and amps - no need to run the speaker cables through the sub, and no phase distortion.

2nd part: I don't hear the "one-note" characteristic you're describing. When the Spicas were on 26" stands, the resulting resonance created this effect, but now that the Spicas are lower (i.e. height no longer equals distance from walls), the resonance is gone and bass tonal response is fairly smooth. On plucked acoustic bass, no one note stands out from the others.

3rd part: The Mission 700AS is a 10" ported sub with a pretty smooth output from 30Hz on up. Not sure it's all that fast, though. I've got one working unit with a banged up cabinet, and one mint one with a blown amp and driver. The amp can be repaired, but I'm not having much luck finding a replacement driver. I hear what you're saying about a stereo pair, but if I can't get replacement parts, I might have to cannibalize the banged up one for parts to get the mint one working. I'm still hoping I can get 'em both working though, for the reasons you cited.

I'd really prefer to take the bass away from the Spicas, rather than running them full-range with the sub, as what they produce is a bit tubby and slow. An active crossover with a 24db/octave slope would do this. Would probably cost $120 for a Behringer CX2310 and some XLR-RCA interconnects (a little worried about the quality of those). I'm also hoping that replacing cheap Monster with Straightwire will tighten up the bass a bit.

Rob - The 60s' sweet spot is pretty narrow. Moving my head 3" left or right collapses the soundstage. Not a problem, though, as I'm the only one listening and my chair holds me firmly in place. As for speaker positioning, the 60s are aimed right at my chair. On the 16" cinder blocks, the tweeters are about 3" below my ears (which is a lot better than 3" above). My chair is very low. 19" stands would put them at exactly ear level. VTI makes a nice pair of 19" stands for $100. The 60s sound best to me around 30"-36" from the front wall. At 24" or less, soundstage depth decreases. For some reason, bass reinforcement was better with the 60s along the long wall. But, as I described in an earlier post, this position didn't work well for imaging. With the 60s along the short wall, I suspect there's some kind of cancellation effect caused by proximity to the corners that's weakening the bass reinforcement slightly. That's okay. I'm not concerned about extending the bass. I'm more interested in making it faster and more detailed so I can better hear the initial transient on a plucked bass string.

However, I realize that I'm probably asking too much from a small, affordable speaker. The main thing now is that the imaging is fantastic. At some point, I've got to either stop fussing and start enjoying, or plunk down some serious cash for a different pair of speakers. Martin Logan Aeriuses for around $1,200 used are tempting, as the Aeons imaged about as well at the 60s and offered better detail and transients. I imagine bass would be a little better, too. But, tax time is going to put a serious dent in my discretionary spending, so I'm waffling.

I'll probably try the active crossover and sub(s), and sell them if they don't clean up the bass.

A question for both of you: Have you heard the Polk Audio LSI9s? An audiophile friend of mine who owns Brentworths and likes my TC-60s keeps telling me I should hear them. I could pay for them by selling my Spicas. I'm a little skeptical that the Polks could image any better than the Spicas, though, and I'm not giving up imaging to get better bass or neutrality. Imaging is everything, and these suckers kick serious butt in that department.