Suggestions for high efficiency speakers?

Where are two Swarm subs positioned in relation to the CAL T-3's?

One is placed against the wall (with the driver facing the wall) to my left. The other is behind me and to the right- it too has its driver facing the wall; in both cases to insure that their output is well within the room boundary.

I was disappointed with how the room goobled up bass when I moved in. So when I found how easy it was to set up the additional subs (according to Duke's instructions) it was quite satifying. I spent less than 5 minutes setting them up after I had the sub amp placed in my equipment stand. That is placing the subs, hooking them up, setting the controls on the amp, connecting my preamp to it- under five minutes. It worked right away- the bass at the listening chair is restored, and because of that the system also sounds more relaxed- a nice pyschoacoustic side benefit.

That was a bit elusive, yes. I tried to touch upon that using a sub setup the way I outlined as being my preference is a matter of having a different "design" goal - i.e.: high-passing the mains fairly high to a pair of subs, (the need for) symmetrical subs placement, high sensitivity, pro drivers, very large overall size and usually not direct radiation - all in the service of loads of headroom in the lower frequencies (that translates into easy of reproduction and very low distortion) and optimum integration. 

@phusis 

If you're crossing higher than about 80-100 Hz, won't you have to place the subs very near the rest of the speaker system?

I get the desire for a high efficiency sub- that prevents thermal compression from being as profound. FWIW I only have 2 of Duke's Swarm subs, as my CAL T-3s take care of everything down to 20Hz in the front of the room. Even at very high volumes, I'v found that the Swarm's drivers aren't moving much. I imagine that could be very different in a bigger room. They are really only there to break up the standing wave though, and apparently don't have to move as much as the front woofers (dual 15" in each cabinet) to do so. So I'm not concerned about thermal compression in this case.

That's dangerously arrogant. You're not acknowledging the alternative, which is conspicuous in itself, and I doubt you've had a pair of symmetrically-to-the-mains placed horn subs or other efficient, large 6th order bandpass ditto (from a point of other design criteria) in your home setup augmenting your CAL's to counter your rigid claim.

Its just physics, physiology and its not my theory- its that of Dr. Earl Geddes IIRC. I'm not certain of what you are trying to say in parenthesis. If you are careful with placement, you can get good bass at the listening position with only two subs. In my case, having done many installations at shows and the like over the last three decades, I've found the DBA to be a nice solution for a vexing problem of getting the bass to play properly where the listeners will be sitting.

I recommend the Swarm becuase its designed to be as innocuous as possible. Its also reasonably priced. I've no financial association.

Having recorded a number of LPs, some of which I mastered myself, its nice to be able to compare to my own expericence of having been there when the recording was made. If you can better that reproduction as you seem to be claiming, I'd love to hear it.

but simply that all mayn’t cry ’halleluja’ over the sonic outcome of the DBA approach, even after being preconditioned by theory.

You can look at this as theory or fact; works the same regardless: at 80Hz the waveform is about 14 feet long. The ear cannot acknowledge any sound until the entire waveform has passed by the ear. It cannot know the frequency of the bass note until 2 or 3 iterations have occured.

In most rooms, if 80Hz, the wave has met the rear wall and is on its way back by the 3rd iteration. It might cancel the energy of the incoming wave, causing a loss of bass. One important takeaway is that the bass, unless the room is enormous, is entirely reverberant.

That is why a DBA works so well- as long as the subs have no output above 80Hz (otherwise they will draw attention to themselves).

The Classic Audio Loudspeakers T1.5 look like very nice speakers but at $72,000 are pretty steep. In comparison to Wison or Magico speaker they are probably a great value. I have never heard a pair but at that price I would certainly travel to hear them. Which model do you own?

The actual price depends on which options are installed. My speakers are the T-3s. They are custom built (slightly taller) so as to be flat to 20Hz. I have the field coil motors on the midrange, with beryllium diaphragms employing a Kapton surround- so no breakups until about 35KHz. They are quite smooth and the field coils make them as fast as ESLs.

I'm a big fan of field coils- they and ESLs offer speed (and for the same reason- the M.O. uses an external power supplythat isn't available any other way. The ear/brain has a tipping point- if the speed isn't there, the brain moves the music processing from the limbic system to the cerebral cortex- robbing the music of some of its emotional impact.

That would be a great option indeed. What’s the price of these?

@phusis 

I’m not sure even though we’ve used them at shows quite a bit. You might inquire with John at CAL.

It’s not the price, really, but size. That is: few pre-assembled high efficiency subwoofer options are available, and the ones that are from the hifi-oriented segment would likely cost a small fortune the likes of Cessaro, Living Voice (not least) and a small handfull of others.

It sounds to me as if you are not familiar with the Swarm sub made by Audiokinesis. Its 1 foot square and 2 feet tall. Its also meant to be placed as close to the wall as possible because its designed to take advantage of the room boundary effect (+3db/octave going down from 100Hz). This allows it to be small and easily placed. In my installation I have the drivers facing the wall rather than the room, to insure the output really is within the room boundary. They work quite well- I use a pair in tandem with my CAL T-3s, which by themselves are flat to 20Hz (and are 97.5dB). Because there is a standing wave in my room, there’s no bass at the listening chair despite the speakers’ capabilities.

Swarm subwoofers

So I use the Swarm subs to break up the standing wave, and now the bass is good anywhere in the room. FWIW, IIRC the Swarms are about 3500/set (don’t quote me on that) so are very reasonably priced and give you excellent bass.

@fosolitude I think its a good idea to replace your Joseph speakers, which are good speakers but simply not efficient enough to really take advantage of what the Jota does. To do that, the speaker should not expect the amp to be pushed past about 20-25% of full power. A friend of mine has that amp; when I tested it, it made about 18 watts.

The Classic Audio Loudspeakers Hartsfield is a speaker that has the efficiency to work with SET power since its about 105dB/1 watt.

But you might consider an alternative- first, high efficiency speakers often trade off bass extension for efficiency and otherwise might be enormous. So what I would do (even if not using high efficiency and also since getting that bottom octave is really expensive with high efficiency speakers), is to set up a Distributed Bass Array to take care of your bass up to about 60Hz. At that frequency getting it to blend with any speaker is a walk in the park. The Audiokinesis Swarm is a great way to do that, and it would be driven by a subwoofer amp independent of the Jota. Talk to Duke at Audiokinesis about this- but do it- this will make the whole thing a lot easier!

Since it would be doing your bass, now you don’t have to worry so much about the bass response of your main speakers which will be driven by the Jota. All you have to do is find a speaker that is good to 60Hz or so and there are plenty that can do that. The harmonics of the bass instruments will convince you that all the bass is coming from the main speakers. The only caveat here is that the speaker will still be getting a full range signal which the Jota will be also playing, so that speaker should be able to handle that even if it can’t reproduce it.

Some of the smaller AvantGarde speakers (Uno or Duo) would do the job and they are not sensitive to the room. An advantage of horn speakers is controlled directivity of the horn, which allows you to reduce side wall reflections which can otherwise cause harshness.

You might also consider some of the so-called ’full range’ speakers using a Lowther, Cube, PHY, Feasterex or similar driver- with the understanding that such a driver will need a tweeter (probably rear firing unless a crossover is used) to insure that you don’t have beamy highs requiring your head to be locked in a vise :) ZU Audio makes such speakers. The ’full range’ drivers won’t be as efficient (96-99dB is typical), but the enclosure they are in will be smaller, unless they are used on an open back baffle.

Spatial Audio and PureAudioProject are both examples of nice open baffle speakers that are easy to drive, although you might be able to run the amp out of gas on them at high volume. But they are a good 6-8dB more efficient than your Josephs and that translates to as if you have an amp that is at least 4x more powerful.

Finally, pay attention to the speaker’s impedance and avoid 4 Ohm loads! Ideally you’ll want to find a 16 Ohm speaker since that will allow the output transformer of your amp to be more efficient and will also allow it better bass response (you can lose an octave of low frequency bandwidth of almost any output transformer simply by using the 4 Ohm tap).