Flex Your PCD Mettle:

[NWCgrad]

Re: Flex Your PCD Mettle:

Better yet, i'll just model it!!! ;)

Thanks Pete for all your help.

Trying to nail down a speaker design is like trying to catch the wind. Once I am home for the summer I will get something built using the eWave deluxe crossover, QSC waveguide, DE250 compression driver and either 1 or 2 3012LF drivers.

Should be fun to explain the lunacy that is DIY to the wife. :eek: She lived through my 18" Mal-X sub build (using NEO Dans 24" sealed cube cut sheet).

[NEO Dan]

Re: Flex Your PCD Mettle:

DL2515II vs KL3012LF
PE 260-401 6"x6" port tube, minimal fill.
This is what I see in BassBox:

[Zilch]

Re: Flex Your PCD Mettle:

DL2515II vs KL3012LF PE 260-401 6"x6" port tube, minimal fill.

Unless I'm interpreting it wrong, that ain't quite working for DL2515II.

I'd try normal and heavy fill first, and if that didn't get it, start tweaking Fb, maybe?

[NEO Dan]

Re: Flex Your PCD Mettle:

Unless I'm interpreting it wrong, that ain't quite working for DL2515II.

I'd try normal and heavy fill first, and if that didn't get it, start tweaking Fb, maybe?

The target spec is -6dB at 80Hz with the crossover in place, so it's close. I will also be within a foot of the side and rear boundary's so I doubt I'll need any BSC.

[Zilch]

Re: Flex Your PCD Mettle:

You're good to go, then, looks like.

KL3015 might be a candidate, as well....

[Pete Schumacher]

Re: Flex Your PCD Mettle:

You're good to go, then, looks like.

KL3015 might be a candidate, as well....

Don't forget the Lambda 15s from John at AE Speakers.

[NEO Dan]

Re: Flex Your PCD Mettle:

I'm thinking that the DL 15" is more than enough in this configuration. Excursion is held to +-2mm @ 100W, It takes 600W to get to x-max. Performance vs $ at the wholesale price, these can not be beat IMO ;)

[Zilch]

EconoWave Delite 12:

DeltaLite II 2512 and B&C DE250 on QSC 152i waveguide in Dayton KD trapezoid cab:

Crossover:




Vertical Polar Map:




Schematic:




Bill of Material:

[penngray]

Re: Flex Your PCD Mettle:

Will we see a BSC circuit?

Im currently using Speaker workshop to build my first passive crossover (TD12M/BMS4550 on the QSC waveguide) and Im curious to what the circuit will look like added to your schematic.

[Zilch]

Re: Flex Your PCD Mettle:

In wider-baffle designs such as these, baffle step occurs at lower frequencies, and the compensation is incorporated into the core lowpass filter.

We cannot measure accurately in the region of interest, so it's somewhat of a crap-shoot.

Others may have a better answer, but that's my take on it with respect to these 12" EconoWaves in 17" wide cabs....

[penngray]

Re: Flex Your PCD Mettle:

Thx, so in the plots above I should just ignore the drop off below 250Hz?

[penngray]

Re: Flex Your PCD Mettle:

btw, Here is my project TD12M/BMS4550 on the QSC HPR152i (You already know about it Zilch :D)

I used your woofer crossover here, it seemed to work decently for my first passive design and my simple BMS4550 crossover (Lpad, signal Cap) to get this.



I didnt like the drop at 2KHz so I moved the cap behind the Lpad on the tweeter schematic, I got this...



Reversing polarity on the tweeter confirms a null


Now this was originally an active build but Im learning how to build passive crossovers. The woofer is front mounted so there is more AC offset that I havent dealt with and Im sure the polars will show this issue.

[penngray]

Re: Flex Your PCD Mettle:

What is the difference between the

Dayton PMPC-15 15uF 250V Precision Audio Capacitor

and

Dayton DMPC-15 15uF 250V Polypropylene Capacitor

besides double the price tag?

[Zilch]

Re: Flex Your PCD Mettle:

Thx, so in the plots above I should just ignore the drop off below 250Hz?

They're MLS and the gating is shown in the legend, time and equivalent frequency. You know the drill about this by now. :o

I didnt like the drop at 2KHz so I moved the cap behind the Lpad on the tweeter schematic, I got this....

I suspect the vertical null is intruding, and you are measuring from below the axis. See my vertical polar map, above; you MUST find the forward axis and design from there. Otherwise, it's like squeezing a balloon -- EQ that notch and it'll become a peak at another vertical angle. These interferences are NOT minimimum-phase phenomena.

Yes, with every change, you have to find the axis again, or you're not comparing apples. Install a polarity reversal switch on the HF driver to facilitate. The forward axis is where the inverse null is deepest, and you'll find changes in vertical height of the mic as small as 1/16" are measurable. The horizontal measurement distance must be kept constant; time to brush up on trig. ;)

What is the difference.

Tolerance....

[Zilch]

Flex It - Round #3:

Eminence Deltalite II 2510 and B&C DE250 on 18-Sound XT1086 waveguide in a more conventional form-factor 1.6 cuft original large Advent, closed box:



XT1086 has been DIY buzz for several years, but few builds are posted in audio forums, perhaps because they cost $88 apiece, MSRP:

http://www.loudspeakersplus.com/product.asp?specific=jmmmfrlnq

An excellent performer according to Brandon's (Augerpro) measurements with DE250:

http://sites.google.com/site/drivervault/driver-measurements/horns-and-waveguides/18-sound-xt-1086

Factory data:

http://www.eighteensound.com/index.aspx?mainMenu=view_product&pid=178

What I've got for my first attempt:




In the files below:



Measurement distance = 45"
C/C distance between woofer & waveguide = 11"
FRD measurements w/minimum phase from midway between them.
Woofer piston diameter = 8.5"
Waveguide throat diameter = 1"

Three earlier iterations* using less expensive drivers on the $6 (last time I checked) JBL Pro MRX/PRX waveguide may be found beginning here:

http://www.avsforum.com/avs-vb/showthread.php?p=18220113#post18220113

*Four, actually, if you click the AK link at post #197 there, that one in the KDT cab with a vintage JBL L100 woofer.... ;)