What do you think of this Pluto variation?

[goldyrathore]

Hi,

I do have some 8" woofers and 2.5" fullrangers with me and was wondering whether something like Pluto could be attempted with these. My gut feeling says its possible.

Now Pluto uses 5" woofer and is crossed at 1khz to the fullranger . Due to the larger size in this variation the crossover need to be proportionatey lowereed to about 650Hz. This freq is not difficult to handle by my fullranger too.

Are there any issues with this line of thought?
Also, can the woofer be front firing instead of top for aesthetic reasons?

Thanks,
Goldy

[gainphile]

I think it would work great! I had wondered about tha too. What pipe are you using?

[pedroskova]

Originally Posted by goldyrathore

Also, can the woofer be front firing instead of top for aesthetic reasons?

Thanks,
Goldy

If you were to do this, you'd be defeating the whole purpose of the design, i.e., omnidirectional behavior in the lower frequencies.

[Bill F.]

Also, I'm afraid that using a 2.5" wide-range driver for the treble would represent another significant divergence from the Pluto principles. It's larger diameter means it will likely start suffering narrowed directivity at a much lower frequency than the Pluto spec.

As Pedroskova just pointed out, omni dispersion as high as possible is a primary goal of Pluto.

However, this is not to say that the 2-way you describe won't sound good. It may sound great, but it won't share much in common with Pluto.

[dewardh]

Originally Posted by pedroskova

If you were to do this, you'd be defeating the whole purpose of the design, i.e., omnidirectional behavior in the lower frequencies.

Why? The woofer can still be omni up to the (lowered) crossover point . . .

Originally Posted by Bill F.

using a 2.5" wide-range driver . . . It's larger diameter means it will likely start suffering narrowed directivity at a much lower frequency

""Much" lower? How "much" lower in frequency will beaming begin with a (nominal) 2.5" driver than with a (nominal) 2" driver? And how "much" will that matter ? ? ?

[Bill F.]

A typical 8" driver will be roughly -3dB @ 90 degrees at that frequency. Not what I would call omni radiation, but I suppose the distinction might not be that perceptible.

Sorry, I missed the fact that the Pluto tweeter is 2" nominal. I thought it was smaller. So the difference between that and a 2.5" driver may not be that much of a factor.

[planet10]

Go for it...

dave

[AdamThorne]

I've been thinking of something like this for a while... do it and tell me how it works!

[goldyrathore]

Originally Posted by gainphile

I think it would work great! I had wondered about tha too. What pipe are you using?

I am about to purchase a plumbing pipe of approx 8" dia. Thats the widest the store has.

Originally Posted by pedroskova

If you were to do this, you'd be defeating the whole purpose of the design, i.e., omnidirectional behavior in the lower frequencies.

The original 5" is very much omni in its entire range of use because the range of use is much less than its CTC equivalent wavelength. How does it matter whether it faces up or forward?
Is there something I am missing?

Originally Posted by Bill F.

Also, I'm afraid that using a 2.5" wide-range driver for the treble would represent another significant divergence from the Pluto principles.

I am aware of the reduced directivity at the higher freq range. The 2.5" fullranger has a dust cap. I intend to replace the dustcap with a DIY phase plug similar to this one Tang Band W3-1878 3" Full Range Driver | Parts-Express.com
If I get encouraging results with the system, I intend to replace it with the Aurasound 2" as in Pluto.

Originally Posted by Bill F.

A typical 8" driver will be roughly -3dB @ 90 degrees at that
frequency. Not what I would call omni radiation, but I suppose the distinction might
not be that perceptible.

Bill, The same -3db @90 (approx) figure applies to the 5" woofer used in Pluto. May be the 5" is special and more omni than a typical woofer, I dont know. You seem to be saying something that is not obvious?

[gainphile]

Originally Posted by goldyrathore

The original 5" is very much omni in its entire range of use because the range of use is much less than its CTC equivalent wavelength. How does it matter whether it faces up or forward?
Is there something I am missing?

Theoretical or measured?

I did an experiment with the 5" pluto clone by lowering the xo from 1000...900...800 etc. The sound should not change as you know it should be omni. But in fact it does change.

Unfortunately I only measured 0-180deg. Had I measured 0-360 deg. the resulting graph could be interesting.

In your case I would simply build a test box of both, measure 0-360, and decide.