UPDATE 04-04-15, Single Driver Experiments

[Mark Hardy]

Single-driver speakers are fun. PartsExpress' best IMNSHO was the Pioneer cat. no. 269-469 of some years back (NOT the more recent ones) that sold for as little as 69 cents each. These are excellent sounding drivers as is in a BR enclosure and efficient enough for anything down to at least a SE 2A3 amp. The most outrageous documented use of these drivers is probably: http://www.ratch-h.com/farm.html

The best bang for the buck FR's that I've heard are the Fostex FE206 and FE207. Qts of the latter is high enough to get away with a simple bass reflex enclosure. I personally like these BETTER than any Lowther implementation I've heard, but YMMV, as they say.

I assume y'all know the Full Range Driver site and forum? www.fullrangedriver.com and www.melhuish.org/audio

[DizRotus]

It only took a year but I finally got the enclosures operational. They exceed my expectations. The neighbors wanted to hear them after watching them under construction. They were amazed that the sound was coming from the new smaller speakers rather than the Klipsch Cornwalls.

In the attached photo, extra drivers and motor boards are resting on top of the speaker. I decided to attach the motor boards with wing nuts to permit relatively quick changes. A rubber gasket seals the driver to the motor board and another rubber gasket seals the motor board to the enclosure.

The immediate improvement in the sound as you put the motor board in position while the driver is playing is amazing. The sound goes from thin with no bass to full with abundant bass. The most surprising part is that the change takes place as soon as the motor board is near the anchoring bolts, and only improves marginally as the wing nuts are tightened.

All three of the Tang Band drivers sound very good. The 616S and 654S sound similar to each other. The 656S sounds different; its too early to say which sounds better. Listening had to be suspended to watch the Detroit Pistons in game 5.

Tomorrow I will attach the two Pioneer drivers to motor boards. Im eager to hear them, especially the 39 cent driver.

Eventually the enclosures will be cleaned up and painted black. It was always my intention to make experimental cabinets rather than furniture.

[DizRotus]

Tang Band and rear horn apart

Edited November 15, 2013 by DizRotus

[boom3]

I am very familiar with the FE103 (not the Sigma). I used it in many projects over the years. It is one of the better cone midranges out there and has a low Fs and Qts for its size. However, I really don't think any enclosure will help it to have significant bass below 100 Hz. If I had to use it as a single driver, I'd use a transmission line. It's response is fairly smooth up to about 5-6KHz were the break-up nodes set in and the curve gets rough. I'd recommend an 18 dB/octave transition to a good ribbon tweeter at no higher than 5 KHz.

[DizRotus]

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On 5/29/2005 7:37:02 AM filmboydoug wrote:

Unfortunately, these are not the most suitable drivers for a rear loaded horn enclosure. I investigated a similar project a while back and learned that for a back loaded horn enclosure you want to stick with a driver with a QTS of about .2 - .3 or so. The TB's are in the .5 area and the pioneer is .76. The Fostex that enclosure is intended for is .36.

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It was understood from the get go that these are not optimal drivers. The Qts (whatever that stands for, I welcome an education on this) of the W4-656S is 0.35 (see attached pdf). On paper it appears to be the best of this bunch.

After a short amount of listening, the W4-656S seems to be the best of the bunch. All of the drivers benefit tremendously from the enclosure. The bass is abundant within their limitations.

Although the Fostex enclosure plans do not call for it, I'm going to experiment with stufffing the early part of the horn with wool or Dacron. Listening to the male voices of radio announcers indicates that there is too much midrange coming from the rear of the cones. Perhaps stuffing will filter the highs and mids while allowing the lower frquencies to pass.

It's hard to imagine that the Fostex FE 103E at ~$32.00 can sound significantly better than the TB W4-656S which cost ~$18.00 when I received it as a gift (it's now ~$23.00 from Parts Express). I still intend to try the Fostex units some day to satisfy my curiosity.

[filmboydoug]

Qts: The losses or relative damping (ratio of stored to dissipated energy or ratio of reactive to resistive energy) of a driver, considering both mechanical and electrical resistances.

Like half of these speaker terms, I have no clue what this means. I just remember that lower is better.

[sunnysal]

have you been able to measure how low the speaker is going? (my guess is about 100hz) before dropping off? congrats on the build and experiments. tony

[DizRotus]

The 39 cent Pioneer drivers sound very good, worth at least a dollar. The enclosure benefits each of the five drivers used; some more than others, but each sounds much better than in free air.

I've just begun to experiment with damping the enclosures. In keeping with the low budget theme of the experiment, I eschewed long fiber wool or even the stuff from Parts Express for bagged genuine Poly-Fil ® (20 oz. for $3.50) from Michaels. The early results are promising. The vocals and piano in a live recording now sound more natural.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Just when I think its sounding real good I switch back to the Cornwalls for a reality check. The Cornwalls are better at the extremes, and they are more efficient. The imaging of the single driver is better, though.

I do not have the ability to measure the frequency response. Nevertheless, with the W4-656S, using a bass test CD that goes from >300 Hz down to 10 Hz in 10 Hz steps, there is clearly usable output below 100 Hz.

These speakers are well suited to playing jazz combos; the percussion and string bass are tight. The single driver concept is not suited for rock or symphonic music. Although less efficient than Klipsch, Im able to drive them to decent volume levels with the ~11 watts/channel of my Dyna tube amp.

[DizRotus]

The TB 616S has a silver metal "phasing plug." Whats the purpose of such a plug? Intuitively it seems that the added mass would only be detrimental to the ability of the cone to change directions rapidly.

I've heard the EV T-35 described as having a phasing plug also. But, after replacing numerous T-35 diaphragms, I know that its plug is part of the metal housing and not the diaphragm, i.e., it would add no mass to the moving diaphragm; not like on the TB 616S.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

[filmboydoug]

Dizrotus, I'm not savvy enough to explain the benefits of a phase plug, but I can tell you that lots of DIYers that post on other forums carve them out of a wooden dowel and glue them onto to the 49 cent pioneers!

[DizRotus]

Oops! I just discovered that the "phasing plug" does not appear to be attached to cone, i.e., it does not add mass to the cone.

[Marvel]

Check this out:

Phase plug

[DizRotus]

Thanks Marvel. I assumed it did something like that, even when I mistakenly thought it moved with the cone.

I thought you were going to take a summer hiatus from this Forum.

[Marvel]

It's a disease...

I check in on things and no one answers the call so I plow blindly on. Work is pretty stressful at the moment, so this has once again become a break.

We're on the downhill side of summer now though. The days will start to get shorter. The youngest heads off to college this Fall. I am really wanting to build some cabinets, but really don't have the time or funds, as repairs on our house are on the schedule for early July.

I came to this forum originally so I could find out about building some LS clones. Still haven't made them, but something better is on the horizon (just can't let the cat out of the bag yet). But I do have the Heresys to make noise with.

But I won't post as much for a while.... maybe.

[boom3]

A phase plug on a direct radiator speaker is purely cosmetic. The cited web page about phase plugs is typical 'audiophile' pseudo-science and wishful thinking. the 'delicate midrange' waves they are fantasizing about are so big, compared to the phase plug that they will refract around it, not be reflected by it.

A phase plug only works_in a horn driver_ if the surrounding air chamber is also configured correctly. The plug and the chamber work together to ensure that all path length from all parts of the the diapahram to the throat are equal at all frequencies. Since there is no corresponding chamber on a direct radiator, it can't work as true phase plug. Yeah, they _look_cool.

[DizRotus]

That makes sense. I guess that leaves me unphased on these.

[Marvel]

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On 6/24/2005 8:52:33 PM boom3 wrote:

A phase plug on a direct radiator speaker is purely cosmetic. The cited web page about phase plugs is typical 'audiophile' pseudo-science and wishful thinking. the 'delicate midrange' waves they are fantasizing about are so big, compared to the phase plug that they will refract around it, not be reflected by it.

A phase plug only works_in a horn driver_ if the surrounding air chamber is also configured correctly. The plug and the chamber work together to ensure that all path length from all parts of the the diapahram to the throat are equal at all frequencies. Since there is no corresponding chamber on a direct radiator, it can't work as true phase plug. Yeah, they _look_cool.

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Sure, Boom. But I also think that B&C know what they are doing as well.

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=294-650

And I think Klipsch had them on the Preomiere series that hasn't come out. Why spend the money if it is only cosmetic? That's not really the Klipsch way. Do we nees a BS button here?

[Klipschguy]

Neil,

I've experimented with and built some rear loaded "horns." The key to the driver is a powerful magnet coupled with a lightweight cone. A lightweight cone is CRITICAL to the backloaded horn sounding reasonably musical and dynamic. Look for lightweight paper with a cloth surround - ideal. A polypropylene cone with a rubber surround is the opposite of what you want. A heavier cone will sound dull and overdamped. For a good value, stick with the Fostex. Believe it or not the FE83 makes a nice sound in a backloaded horn. Talk about a lightweight cone! Stay away from their "wood" cones - they sound dull to me (and more expensive to boot).

When tweaking your backloaders, the amount of damping in the chamber is THE critical component for getting the sound right. Start with none - listen. Stuff it - listen. Hopefully your chamber is well enough designed that the first will sound too lively and the second will sound overdamped. Now find the balance. If unstuffed, it sounds just a little too lively - just use a little damping, or vice versa. You get the idea.

Backloaded horns are a little ideosyncratic, but can sound quite good with certain types of music. If you like three piece jazz, you'll like the backloaders. If your a rocker, then don't waste your time.

(I hope Tom Brennan doesn't see this thread - he is not to hip on Ed Schillings' FE103 "Horn"...something about TV speakers...) I have some FE103's. They're alright. I like the little FE83 better though.

Andy

[DizRotus]

Andy-

I just checked out the specs of the FE83 on the Madisound site. It looks like it would be worth investigating. Thanks for the input.

[boom3]

Sure, Boom. But I also think that B&C know what they are doing as well.

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=294-650

And I think Klipsch had them on the Preomiere series that hasn't come out. Why spend the money if it is only cosmetic? That's not really the Klipsch way. Do we nees a BS button here?

_____

Yeah, we do-for B&C, Tangband et al and if Klipsch uses "phase plugs" on direct radiators, for them as well (gasps of horror from the assembled faithful)

Cosmetics sells. Like the "coppery" look of some Klipsch cones, like phase plugs, like spoilers on econoboxes, like racing stripes on my mother's Buick...it's the sizzle, and not the steak. When Paul published his first list of Major Breakthroughs, he included his Shorthorn. "Yup, we did it too" he admitted. Marketing vs. engineering...guess who wins? A manufacturer's high reputation for one product line is not a nimbus of credibility that covers all they do, they get pulled along by the tide of fads just like everyone else.