What speakers for 300B S.E.T ??

I've tried a few things in the SET area, regarding speakers.

The first thing is that nothing replaces high efficiency/sensitivity when you go to low power amps. You need to get as high sensitivity speakers as you can. This gives you more headroom, and reaches deeper into the detail.

Regarding the Hornshoppe speakers, they are nice and made pretty well, and sound pretty good. But I have used FE103 drivers in a few designs, and they just don't get into the bass very well, and what bass they do produce is restricted by the very small amount of air that a small driver like that can move. You will find that they lack in the bass.

When I switched from FE103 based speakers to Lowther EX3 based speakers(Voigt Pipes), the difference was staggering. Better all around sound, much more headroom, gobs more bass, way more detail, just way more everything.

I'd agree that the Cain and Cain Abbey speakers would be a good try for your under $1k budget. They are a Voigt Pipe design, and have the single-driver advantage that mates well with SET amps. However, the Fostex drivers will not sound like a Lowther, and although they are good, the Lowther drivers are way better. I made my Voigt Pipes myself(very easy to do), and spent my $1k on the Lowther drivers. I made a few custom changes to mine, and drive them with my Berning 45 SET-ZOTL(2 watts per channel) and an analog front end. Very awesome results down to about 40Hz on the bottom end. Max SPL peaks at around 106db.I really don't notice any "lack of bass" with this system. It is so good at doing 40Hz and up, that the few things that actually occur below 40Hz don't make a difference in my enjoyment. Of course if you are a pipe-organ fan or something, you'll need a sub. I did make some mods to my cabinet which overcomes the baffle-step losses which are typical in this type of system, so my bass is better than other Voigt Pipe designs.

Regarding your comment that Lowthers are too expensive to experiment with, you can just build an easy cabinet like a Voigt Pipe, and you can be good-to-go for under $1500/pr complete with Lowther EX3 drivers.

The down-side is that they are pretty large, and may be a bit taller than your size requirement dictates.

Dilly, the Lowther drivers don't really have a limited life span, it's just the cone/suspension surround which will degrade over time, just like any other driver. Lowthers use a foam type suspension surround, which probably lasts about 12 years or so. When it starts to go bad, you can just get them redone by the factory.

I can't comment on the particulars of those two amps you are considering.

Dilly, try this link
http://kosat.consultit.no/~ketil/lowther/voigtpip.html

The dimensions shown in those plans are metric, and are INSIDE DIMENSIONS.

I have used the Lowther EX3 in this enclosure, and found it to be the best match, in my opinion. I also made some mods which would be important in getting the best bass response. Contact me if you are going to make these, and I'll give you the information you need to do this.

Boa2, the Voigt Pipes are kind of a combination of rear-horn, transmission line, and bass reflex. They are not the same as the more typical horn speakers, in that they are direct radiator dynamic for most of the frequency range, and use rear-loaded backwave for augmentation of the frequencies below 400Hz, to counter the natural slow rolloff of the driver that begins around that point. The cabinet is actually tuned for 41Hz, and that is about the bottom end of the system.

I tend to prefer a rear-horn over a front-horn system, but I have heard some very nice front horns too. The Voigt Pipes can manage somewhat deeper bass than most true horns because they are not limited by the mouth/taper/length considerations that limit the bass response. Most true horn Lowther systems cannot reach as deep as 41Hz, due to the nature of the horn designs, and the size limitations for home use.

I made my Voigt Pipes because they were something that would perform well, and were easy to make, and were in my budget range. They allowed me to spend the bulk of the budget on the drivers, and saved money by DIY cabinets.

With a couple of mods, they perform quite admirably, and I like them very much. They are about the easiest cabinets in the world to make, and they make entering the "Lowther world" much less expensive, and very enjoyable.

Thanks for your nice comment about my system. It is modest, but I like it.

Howard, I found that this project was very rewarding and enjoyable to do. If is alot of fun to play with single-driver systems, because alot of the complexity of making speakers(crossover design and building/tweaking) is eliminated. Basically if you can do a good job of putting the cabinet together, you'll have good results. This is already a proven cabinet, and has been around for about 70 years now, originally designed by P. Voigt who was the original designer of the Lowther driver. Also, as can be seen by the Cain & Cain Abbey, and some other Voigt Pipe designs commercially available, this cabinet has the characteristics of working as intended, even when a variety of drivers are used. Fostex 8" Sigma drivers work fine, all the 8" Lowther drivers, AER 8" drivers, REPS-1 drivers, even little FE-103(4") have been used successfully in these Voigt Pipe cabinets. That's one of the things that makes Voigt Pipes so popular with DIY people.

One of the key issues with Voigts is to make sure the cabinet stuffing is done right, or the tonal balance will be off because of the lack of "blending" the port output with the direct radiator output. This has to be done properly. The cabinet stuffing determines how strong the midrange output will be, and has an big effect on the flatness of the frequency response. If you have too much midrange coming from the port, then there is a hump in the midrange response(and also an imaging shift) and below, and if you don't have enough, then there is a dip in the midrange response and below. Adding more stuffing makes less midrange output of the port, and taking away stuffing makes more midrange output at the port. You strive for an even balance, so that the port does not call attention to itself.

Many articles on Voigt Pipes make a big issue out of the possible "comb filtering" effects of the interactions of the direct radiator and the port mouth. They say it results is some harmonic cancellation of certain frequencies that are multiples of the cabinet resonance tuning. In practice, I have observed none of this, and either I got very lucky, or they are making a mountain out of a mole-hill. I wouldn't worry too much about comb-filtering on these.

Lowthers and most single-drivers take a very long time to properly break in. The mids and highs come in quite early, but the bass response is weak until at least 100 hours of play time. It continues to improve up to around 500 hours of play.

Even after break in, there can be a desire for a little more bass impact, and the "swinging door" mods that I designed and implemented on my speakers address this issue. It is related to the boundary effect, and wave-launch off the front baffle, and it is called "baffle-step loss". The narrow cabinet fails to reinforce the lower frequencies and results in a 5db loss in response below about 128Hz. The wider baffle face that is provided by the "swinging door" mod handles this by acoustically providing the added surface that is needed.

For those of you who were contemplating the Voigt Pipe systems, I have just received a digital photo from a friend, KK, who made a set last week, with my mods on them.
He loves them. They look very nice, and really look just like mine.

Here's a link to the photo

http://cgim.audiogon.com/i/vs/i/f/1100956236.jpg