THE PENCIL: inspired by Ohm Micro Walsh Tall

[Juspur]

Drivers: Peerless 832873 and Morel MDT-40 (tweeter).

Cross-over is just a 2. order Linkwitz Riley for the tweeter at 6 khz, 1,8 uF in series + 0,39 mH in parallel - Because the Peerless is ultralinear and has a natural rolloff at 6 kHz with 12 dB/octave rolloff

The enclosure is 10 liter, 71 cm tall, 12,1 x 12,1 cm internal.
The port (on the back of the speaker) has Ø 5,7 cm, length 10,5 cm.

The "tweeter-protector" on top is just a pencil-holder turned upside down

The costs is about US$ 500/euro 300 total for a pair. It's easy to build, and don't take up much space (except the sound, which is very spacious

The sound is fantastic - very dynamic, slam-bass, and a very natural soundstage. This is a speaker, where I don't skip music, but listen to music, I previously wouldn't have - THE PENCIL simply plays MUSIC... Try it, build it.





Regards, Jesper

[ashok]

Looks great. I built some speakers firing upwards with a deflector cone above it and a tweeter above that . Pity I have no pictures . It was made for a friend in the 80's and I guess the unit isn't alive anymore.
Maybe you should have a grille perforated like the tweeter , for the mid/bass also .
Theses kinds of arrangements do give a very spacious sound but if I remember correctly , it didn't give a rock solid image like some standard speaker arrangements do.

Great job.

[Badge]

I would have chosen a much lower X-over point, but that is a just my perspective. The MDT-40 is a good tweeter. I have a pair and my plan is similar but will use the B&O omni reflector approach.

[GDJ]

Very nice job! Love the look of the pencil holder.

[c2cthomas]

Similar to this: http://www.diyaudio.com/forums/attac...amp=1176356499
Perhaps a little of Mamboni Magic or BudP EnABL Voodoo!!! I have found that my Walsh 5 remakes are very nice speakers in respects to being an "omni" directional type of speaker. I find them great for my HT and general listening.

[Juspur]

Originally posted by Badge
I would have chosen a much lower X-over point, but that is a just my perspective. The MDT-40 is a good tweeter. I have a pair and my plan is similar but will use the B&O omni reflector approach.

Yes, the Morel is a very good tweeter. Not very fond of xovers in general, this is the most minimalistic I found useful. 6 db/rolloff is - in my opinion - not steep enough in general to protect tweeters properly . The standard xover-point in the 2-3 kHz range is generally bad, from an listening point of view (our ears are very sensitive in that area). So to create speakers where the crossoverpoint isn't audible, you'll have to either move upwards in frequency (as I do) - or down, which makes huge demands for the tweeters in 2-way systems.

But THIS Peerless bass/midrange is exceptional for this kind of speaker - a very wide frequency range, no peak at the upper frequency, and a natural and fine roll-off... See datasheet here

[Juspur]

Originally posted by ashok
Theses kinds of arrangements do give a very spacious sound but if I remember correctly , it didn't give a rock solid image like some standard speaker arrangements do.

You're right - the image is not sharp as "**** in snow", but more "natural" - I'd say it pretty much reflects the image at an acoustic jazz-concert with no electric amplification.

Regards, Jesper

[OhioTanner]

what is damping foam? anyone?

[Juspur]

Any damping foam - I've used foam from a mattress.

BTW, I've changed the x-over. Now it consists of only a 2,7 uF in series with the tweeter. Simpler, and recommended by ear

[Tyimo]

Jesper!
Nice speaker!
Could you tell me how you speaker works?
Is the midwoofer radiating upwards or down into the box??
Is it connected in phase or in reversed phase?

Greets:

Tyimo