Flex Your PCD Mettle:

[Pete Schumacher]

Re: Flex Your PCD Mettle:

It's easy enough to move the baffle forward to accomplish that, as Jack earlier demonstrated.

We're at +/- 2 dB, but there's certainly no harm in doing better.

I'm trying to figure out why the 3012LF system doesn't show so prominent a peak at 4.8 kHz as the HO here....

What XO values on the tweeter are being used for the plots above?

[Zilch]

Re: Flex Your PCD Mettle:

What XO values on the tweeter are being used for the plots above?

4.7 uF and 1.0 mH, then 2.7/8 Ohms.

It got bumped to 4.7 here:

http://techtalk.parts-express.com/showpost.php?p=1631585&postcount=112

4.3 was intermediate to that shown.

I'll try it again at 3.9 (4.0)....


Edit:

Forward axis did not move appreciably, XO went up ~50 Hz, flatter response overall:

[Ship it? ;) ]

[Pete Schumacher]

Re: Flex Your PCD Mettle:

4.7 uF and 1.0 mH, then 2.7/8 Ohms.

It got bumped to 4.7 here:

http://techtalk.parts-express.com/showpost.php?p=1631585&postcount=112

4.3 was intermediate to that shown.

I'll try it again at 3.9 (4.0)....


Edit:

Forward axis did not move appreciably, XO went up ~50 Hz, flatter response overall:



[Ship it? ;) ]

That looks real nice. How's it sound compared to LF?

[Zilch]

Re: Flex Your PCD Mettle:

That looks real nice. How's it sound compared to LF?

Same stunning clarity w/3-4 dB more efficiency.

I'm not sure about the baffle step comp; seems like we'd have to give up some of that sensitivity for them to be equivalent in the midbass region. I'll measure the final comparison, normalized for SPL.

Notwithstanding the excursion issue, the HO does not accept assist at 30 Hz as effectively; there's less actual boost than with LF.

If there's no further changes, I'm calling this a wrap. There's going to be a Round 2.7, though, using Deltalite II 2512 which has the lower Fs of Kappalite 3012LF plus nearly the efficiency of 3012HO. They also cost $50 apiece less than Deluxe's 3012LF.


Edit:

LF raised 3 dB. In this direct comparison, the behavior at 4.8 kHz is all but identical; that's where I normalized:

[Mayhem13]

Re: Flex Your PCD Mettle:

Slow down chief, you've got the 2510 version to finish.....remember? A couple o guys over there need a speaker like this before they start building more active line arrays.:eek:

[edlafontaine]

Re: Flex Your PCD Mettle:

...from the way things are going, there will never be a "definitive" version...just continual fun...lookin' forward to the 2512 ;)

[Zilch]

Re: Flex Your PCD Mettle:

Slow down chief, you've got the 2510 version to finish.....remember? A couple o guys over there need a speaker like this before they start building more active line arrays.:eek:

2510's not the issue; I don't like the HF yet in the build; it's crossed too high for that c/c distance. There's additional compression drivers on the way which may rescue it. Still months away on 122i waveguides, so I may just punt and go to DE250/XT1086 with that next. :D

...from the way things are going, there will never be a "definitive" version...just continual fun...lookin' forward to the 2512 ;)

3012LF's the benchmark thus far; it'd be nifty to get the $$$ down a bit....

[Zilch]

EconoWave Deluxe HO:

[Dennis H]

Re: Flex Your PCD Mettle:

The LF version of the Kappalite 12 looks like it's better as well for those wanting a small sealed box to cross to a sub at 80 Hz using a receiver's crossover. 'Perfect' box tuning for that would be Q=.7 at 80 Hz. In the pic, a .9 cu.ft. box with light stuffing gives:

Yellow: HO (factory TS), Q=.64 at 111 Hz
Green: HO (Brandon's TS) Q=.72 at 106 Hz
Red: LF (factory TS) Q=.65 at 80 Hz

80 Hz sensitivity is about the same for all of them and that's going to be what determines system sensitivity. The signal is 1W into 5.6 ohms.

[Zilch]

Re: Flex Your PCD Mettle:

80 Hz sensitivity is about the same for all of them and that's going to be what determines system sensitivity. The signal is 1W into 5.6 ohms.

Hello, Dennis.

Just to be clear, you are suggesting that in this small (0.95 cuft) vented alignment normalized to 80 Hz, the efficiency advantage of HO is moot once its response is flattened for equivalent performance?

In a larger cabinet, HO could be optimized to retain that advantage, or some of it, however, LF merely getting there in a smaller package with somewhat lesser system efficiency, no?

3-4 dB's not a big deal for many builders, but to "First Watt" enthusiasts, it matters.

[Deltalite II 2512s are here, BTW, for Round 2.2.... ]

[Dennis H]

Re: Flex Your PCD Mettle:

Hey Zilch,

Here they are in a 1.75 cu.ft. ported box tuned to 45 Hz. The signal is boosted in these to the more typical 2.83V or 1W into 8 ohms. The sensitivity advantage of the HO is in the midrange and will most likely be lost if you EQ them both flat with the crossover.



Aside: I wish the mods would change the settings for posting pics so we weren't forced to use JPG which wastes tons of bandwidth and washes out the colors in graphs. GIF or PNG files are much smaller and clearer but you can't upload them if they are more than 280 pixels high.

[Zilch]

Re: Flex Your PCD Mettle:

Thank you, Dennis.

Could you throw the Deltalite II 2512 into this mix for us, please?

Brandon recommended trying it, which we're about to do here....

[Dennis H]

Re: Flex Your PCD Mettle:

The Deltalite looks sweet if you can handle a big enclosure. Nice bass extension. I squished the pic down so I could use the PNG format. Note that, no matter what you do, they all have about the same sensitivity at 70 Hz.

1.75 cu.ft. 45 Hz ported box
Green: Kappalite HO
Red: Kappalite LF
Magenta: Deltalite

4.6 cu.ft. 38 Hz ported box
Cyan: Deltalite

[Dennis H]

Re: Flex Your PCD Mettle:

The Deltalite also looks pretty good in a sealed PE box for an 80 Hz cross to a sub. 1.75 cu.ft, fully stuffed, Fc = 76 Hz, Q = .72.

[Zilch]

Re: Flex Your PCD Mettle:

Yes, when I saw how Deltalite II would perform in a larger box, the wheels started turnin' here.

In the PE trap cabs, it's looking more like vintage West Coast. ;)

The Deltalite also looks pretty good in a sealed PE box for an 80 Hz cross to a sub. 1.75 cu.ft, fully stuffed, Fc = 76 Hz, Q = .72.

Shades of Geddes.

[Maybe I'll call it "Model A...." :p ]