Plan B (aka, fun with virtual graph paper)

[grumpy]

Me's welcome :-) No judo chops, please.

My project? Hmm.. well, my components will certainly end up in a project and will
hopefully benefit from discussion here. It appeared that several others had a similar
component set and some interest in putting them together. Horns should arrive in
the next few days

-grumpy

[grumpy]

2352 horns came in. Just had to listen to those 2435's ... doing so now
Setting on 4430 bottom end with the HF peaking circuit dialed way back.
After a few recordings I'm pretty pleased with the potential of this pairing,
and having a hard time imagining (personally) needing more high-end
frequency extension. Will try to run a WT2 impedance plot tomorrow.

-grumpy

BTW, ain't gaffer's tape great ? (haven't drilled horn/driver flange yet)

[audition]

No dimention shall be less than 1/3 any other dimention of the enclosure.

[grumpy]

Thanks for the "rule of thumb" suggestion, er mandate
to aid in confining my dimentia.

[Zilch]

What I'm using right now (1 kHz) for 2435HPL on 2352 with single 2235H in 4507, two ports closed. Tag an L-Pad on the HF out to adjust. Drop the bypass caps if you build with Solens (cheaper, actually). Inductors are Jantzens: L1 = 14 Ga., L2 & L3 = 20 Ga.

[grumpy]

Thanks Zilch. I'll have to see what's missing in my current parts bin
-grumpy

[UreiCollector]

Grumpy,

I like the looks of what you have planned. My personal guideline has always been to avoid any dimension that approaches 1/2 wavelength of my high frequency cutoff (plus 1 octave) for the given woofer. Given that your using such a large horn, I would imagine your cutoff will be pretty low in freq, thus allowing your largest dimension to be fairly big.

I have not experimented with varying box size/shape with constant volume, but have made many enclosures with internal depths in the 14-24 inch range without significant issues.

I would also recommend a generous amount of absorption on the rear wall of the cabinet, to try to “kill that reflection” off the rear wall, from bouncing back into the rear of the cone….perhaps even adding an angled surface behind the woofer to “redirect” that reflection away from the back of the cone.

I think personal preference will come in to play as well....some, for example, don't like horns at all, and prefer the sound of an open dome.......I personally love horns. But of course, we should not ignore the opinions of others.

I’m sure you have put a lot of thought into these, and just wanted to add my personal ideas. Good luck!



I think your desire to build a non-room-intrusive speaker is realistic, and should not be ignored, as you have to live with and love these when they are finished.

[grumpy]

Thanks Frederick,

"a lot of thought" might be stretching things a bit Concern about the
cab depth (lack thereof) and possible issues/solutions seems to be a primary
constructive criticism, and I appreciate the input/ideas. No concrete has been
poured yet, so I'm flexible

-grumpy

[grumpy]

OK, 2435HPL on 2352 and unterminated (have yet to build a test pipe)...

both on floor pointed to 8' ceiling, horn w/o baffle, just floor nearby.

Roughness on horn plot... room noise coupling back? or ??? (not exactly a
quiet environment at my house) Will try a higher drive level later.

-grumpy

[Zilch]

Earl can give precise guidance here, but it looks good for 1 kHz, maybe not much lower, tho....

[grumpy]

That's about what I expected, and what I gleaned from these plots as well.
Fortunately, that's how I expect to use them as well.
Will be interesting to experiment and see what effect boundaries/baffle
will have & compare w/ literature. -grumpy

[Zilch]

I did:

1) 2435HPL on 2352 - same result, basically.

2) 2452H-SL on same - will play lower, if desired.

3) My plots are 100 points, which has inherent smoothing. I repeated 2435 at 1000 points to see if it is actually raggedy.

Well, somewhat.

I'm set at 2000 uA test current.

[grumpy]

Cool... thanks for the verification!
Need measurement tools before more compression drivers

-grumpy

Edit: Other than small bumps above 2KHz, unterminated looks a lot like the published
PWT impedance plot. Interesting (a little) that your example has elevated impedance
values on the top end when unterminated (or odd that mine does not). Will have to
build one (PWT) once I get a mic that's useful for that sort of thing ... just don't hold
your breath

[Zilch]

I didn't do unterminated (no horn, I presume). My second plot is a different (4" Aquaplas'd Optimized Aperture) driver, for comparison of cutoff frequencies of different horn/driver combinations.

[Fodder especially for Earl.... ]

[grumpy]

Ah, well that makes much more sense regarding several features of the center plot 2451-SL? an SL-ized 2447? 2452-SL (the current Zilch darling )?

Yes, by unterminated i meant with no horn. -grumpy