High eff speakers? Sonata III, Super III, OR ???

Any of the klipsch Heritage series

If vintage doesn't scare you, you ought to consider Altec Lansing Models 14,17,18,19. These can be bought for $2000 or less. I own Model 17s with the 604 duplex and have been enjoying them for over 18 months with no thoughts of selling them. Mine are from the mid 70's, but they do lots of things very well. Most range from 96-103db/watt/meter.

Newbee, thanks for the vote of confidence... even if you did "out" me about those dirty posts of mine.

;-)

Okay, both the Silverline Sonatina III and Coincident Super Eclipse III are probably excellent. I say "probably" only because I can't recall for sure whether I've heard either model, but I do like both brands.

Coincident tends to have smoother impedance curves than Silverline. I have't seen impedance curves on either of these particular models, so that's a generalization. But the Silverlines usually have impedance curves that "zig" where the frequency response curves "zag" - so that if there is any rise in response at the impedance peaks due to amplifier/speaker impedance interaction with a low damping factor SET or OTL amp, the frequency response curve will be nudged in the direction of being more, rather than less, flat.

Silverline speakers tend to be on the warm and forgiving side. Coincidents tend to be more neutral, more likely to "out" a bad recording like Newbee with my dirty posts.

Now my personal prejudices lead me to place a higher priority on radiation pattern uniformity than most people do, and eyeballing these two the Sonatina III looks to me like it would have the edge in that area.

Somewhere I stumbled across a rule-of-thumb regarding high efficiency speakers and low power amps - to the effect that you want enough power to get a good 102 dB out of the speakers on peaks. So with 92-93 dB speakers, that's 8-10 watts. You must have done your homework, Blindjim.

The Altecs mentioned by Wwwrecords are also very good speakers. I'm more familiar with the Model 14 and Model 19 than the others, and in my opinion they're very competitive even today.

I have a 92 dB, 8 ohm floorstander that might interest you. Shoot me an e-mail if you'd like details.

Best of luck to you, Blindjim.

Duke

ps - Tvad, what did you end up with?

Tvad - I think I saw that one already, maybe not. I did see one wherein Duke was telling you stuff about matching the amps impedance or something... I've read so many things these past few weeks my eyes are rectangles... and my ears are worn out... and both PCs are in critical care units.

Duke. "sonatina" or Sonata?

I got the impression from what i've read the Di applito config gives a great dispersion, laterally, and vertically. If done right. but it's a tricky thing to do right. I'm assuming Mr. Bloom figured it out.

Like I said above, neither Alans' nor Israels' units are ones I'm strickly looking at.. just there's some press on each. More on Alans. Bill Cowan who did the review on the coincidents and I e'd some on that topic and given my tastes he said to ensure I stuck with the fabric dome tweets. Suits me. Though I know even fabrics can be tuff just like metal ones. sometimes.

RE: impedance matching of amps
What's what there? I mean how can anyone really know what numbers to look for on amps output impedance when you ain't sure if 'EVERYONE' measures those numbers the same? Some amp makers don't even post those numbers.

...and if they are posted, how do you choose one vs. another given speaker makers aren't all measuring the same either...??? Should I send everything to John Atkinson first?

Jim, I meant "Sonata" - sorry. I put one too many syllalables in the word.

In general, the greater the size discrepancy between the drives, the greater the radiation pattern discrepancy at the crossover frequency. The midbass drivers in an MTM array have a much wider horizontal than vertical radiation pattern, and in my opinion this is undesirable if you use a dome tweeter.

Let me try to explain why I think the radiation pattern matters. I'm evidently in the minority on this; most designers don't go out of their way to deal with it, so don't take my word a gospel.

Okay, the ears derive timbre not only from the first-arrival sound, but also from the reverberant sound within the room. At listening distances of more than about five feet, most of the energy that reaches your ears is reverberant sound. Now your ear/brain system suppresses directional cues from this reverberant sound, but you're still picking up loudness and timbre and ambience cues from it.

One characteristic components of live music is, a natural-sounding reverberant field. Live voices and instruments even sound natural from the next room, where there is no line-of-sight to the instruments and therefore no direct sound; only reverberant sound. In contrast, very few loudspeaker systems sound convincing from the next room. One reason is, their "power response" (summed omnidirectional response) is very uneven. I believe this is one of the major causes of the perceived difference between live and reproduced music.

Let's look at why the power response of most speakers is uneven. No doubt you're familiar with "beaming". As an example, let's take a 6.5" two-way speaker, crossed over to a 1" dome tweeter at 2.5 kHz. The woofer's radiation pattern is wide wide at low frequencies, but then it starts to narrow as the wavelengths shrink to where they're comparable in size to the diaphragm's dimensions. So the pattern has narrowed to maybe 90 degrees in the crossover region. Then the tweeter takes over, and the radiation pattern blooms out wide wide again. Eventually the tweeter also starts to beam, but usually not until the very top octave.

The problem region is the lower end of the tweeter's range, roughly 2.5 to 5 kHz. In this region the speaker may well be putting out 8-12 dB more energy into the reverberant field than at most other frequencies. And this just happens to be the region where the ear's sensitivity is the greatest. So what happens is, the extra reverberant field energy in this region makes female vocalists sound a bit harsh, and the eventual result is often listening fatigue (I could explain why if you want).

Now the MTM format's vertical radiation pattern on the M's side of the crossover will be comparable to that of an oval driver the width of one of the midranges but the height of the whole MTM stack. So in the vertical plane, the radiation pattern will be much narrower than in the horizontal plane. The result will be a significantly greater net radiation pattern discrepancy in the crossover region than if we just had a single midrange driver.

Of course there are advantages to MTM's. Much better pattern uniformity in the vertical plane with odd-order crossovers; higher power handling; and reduced floor-bounce reflection energy due to the narrowed vertical pattern (though the vertical pattern will usually be wide once again in the 4 kHz region, where the ear's sensitivity peaks, because that will be produced by the tweeter).

So it's a trade-off. Surprise, surprise.

I'll try to comment on impedance matching later.

Duke