DIY speaker choice for SE

[Drewaudio]

Guys, I'm probably opening a huge can of trouble but I'd really like some guidance on which DIY speaker projects I should consider for an SE tube amp (triode KT88 or EL34). I'd prefer to focus on a floor standing two way design.

Is something like the (now 10 year old) Ariel worth the effort?

Thank you,
Andrew

PS At the moment I'm listening to Quad's ESL63 through a Quad 707 amp.

[Geek]

That depends a lot on your budget.

If you don't have a lot to spend, you might consider the more efficient Tang Band midwoofs and tweeters. If you have a reasonable amount, you might want to think Lowther or Fostex fullrange horn loaded.

Cheers!

[awhite1159]

Andrew,

Why don't you post this question on the full range forum. There are alot of very knowledgeable guys out there that can help you with a speaker DIY project that is high effiency. I can tell you that I like to listen to my music very loud and like it to be crystal clear with alot of range. My system used to be a three-way with the Adcom GFA5802 SS amp (450w RMS per channel @ 4ohms) driving the mids and highs and an Anthony Gallo Reference Sub amp driving my subs rated at 250w RMS per channel. Sounded good and got very loud. I have converted to a tube amp with high efficiency speakers and will never turn back. My point is that I now have a tube based amp that with only a couple watts driving a pair of back loaded horns with the Fostex FE208 Sigmas get just as loud and sound simply astonishing. There is a relatively simple build of a horn called a 'BIB' (Bigger is better.) that comes to mind for your project since it is a relatively simple horn build. Horns are the most difficult speakers to build so that is why I mention this.

Good luck with your project.

[planet10]

SE amps tend to sound best with a speaker with a smooth, flatish impedance curve ie tend not to like crossovers. They also like efficiency because they are (usually) fairly low output. So if a 2-way it should be more like a fullrange with a helper tweeter (xoed with a single cap) or an active woofer with a mid-tweeter (usually also classified as a full-range)

dave

The frugal-horn site is loaded with speakers aimed at SE amps.

[Svein_B]

Originally posted by planet10
SE amps tend to sound best with a speaker with a smooth, flatish impedance curve . . . . . .

So how do we achieve that goal, together with reasonable high efficiency?
Aperiodic loading should give a flat[ish] impedance curve, esp. if combined with a zobel to smoth the higher regions.
Since it will not have a port that bosts the lows, we should probably use at least an 8" driver to get some grunt.

Is it time we "re-invented" the Dynaco A25 ?


Svein

[planet10]

Originally posted by Svein_B
So how do we achieve that goal, together with reasonable high efficiency?

If you look at the typical full-range it has a shallow U shaped impedance curve. Ignoring for now any impedance changes in the bass due to bass loading, the high output impedance of a no (low) feedback SE amp, then we have the amp providing more power when the impedance curve rises -- right where the typical FR starts to fall off.

So what we are suggesting is that we won't consider the speaker in isolation from the amplifier.

Here is a start on the subject.

Now to bass loading... aperiodic is a typically better loading than sealed, with a flatter low end bump (ie less power boost in the LF than sealed). If you look at the available FR units it is a challenge to find one that gets you the bass extension you want at the bottom. Because of the impedance bump at the XO in the A25 you get a lower treble boost. And getting any midrange finesse out of a 10" driver is quite the challenge (BTW, the A25 has arisen again in the form of the World Design WD25 -- as i understand from the hand of the A25 designer).

Well then how about bass reflex. The double peak here can be an issue, and since T/S parameters change as we give the boots to the volume control tuning changes depending on volume -- the high output impedance of the SE amp exacerbates a BR tendency to have lumpy bass at some volume. We can try to get some of the advantages of BR while ameriolating its disadvantages by taking a couple approaches (there are probably more). One of these is to push these towards aperiodic by adding some "resistance" to the port. This can be done with long high aspect ratoio ports (exemplified by the Fonken) or by stuffing the port (exemplified by the sock in the port comments). The other approach is to have the port exert iron-fisted control over the alignment. This is exemplified by the BVR (Big Vent Reflex). The monstrous vents contain enuff air mass to dominate the driver. This can be see in the large range of drivers usable in Harvey.

When we get to the really high efficiency drivers they tend to have really low Q -- and it now requires a horn to get any real bass out of them. We end up with ripples in the FR and in the impedance curve. They come in a FR where we are actually accumtomed to frequency anomalies due to the room, and a clever designer can minimize problems to the point where advantages outweigh disadvantages. Some people can ignore this ripple more than others, That BIBs are so popular and that many people (most that actually try them) can live with their ripple is a testament.

dave

[Jaime]

Dewaudio
SET EL34 or KT88 have low power. You need high efficient boxes.
The easy way is go to a full range Fostex FE168EZ in recommended horn enclosures.
Ariel loudspeakers are more expensive, but I believe are a good option too.
Best regards Jaime

[bloozestringer]

Well, I have a set of Pi Tower Two's that I built that put out some pretty good sound with a <1 W 12B4 amp. I've heard them on a EL34 SE amp (10W) as well and they were plenty loud. All of Waynes designs are high efficiency. His horns sound exceptionally good with low wattage (<10W) amps.

http://www.pispeakers.com/contents.html

[Drewaudio]

Thank you guys, you've given me a lot to think about! I'll have to search for the bib design and other full range designs in the full range forum.

Cheers!
Andrew

[Drewaudio]

Well, I've read a heap of posts about dyi full range speakers and I think the FE167e is the driver for me. It's really difficult to choose a driver and cabinet to build based on what people post and without hearing any of the finished projects!

I've selected the FT-1600II as the cabinet which gives the best balance between WAF and performance.

Thank you for your recommendation to go down the full range path. I'll let you know how I get on...

Kind Regards
Andrew