This will be a fun build!!!

Hi Guys.

So, a follow member (Bumbledad) gifted me a new pair of Heil AMT drivers. I decided to build a pair of speakers with parts I have in the shop.

I have a pair of JBL 6x6 horns and a pair of Dayton Audio DT250P-8 Compression Driver.

I also have a pair of DynaLab V22-DR-0003 8" Paper Cone Woofer 4 Ohm that have an f3 of 25hz in a 3 cu ft box.

The CD is solid down to 600hz out to 10khz.

so I want to cross the woofer at 600hz to the CD then cross the CD at 5khz or so to the Heils. I have an active three-way crossover and a handful of amps.

Below is a link to the woofers and a picture of what I’m thinking for the cabs but with the horn above the woofer and the Heils on top like the picture.

DynaLab V22-DR-0003 8" Paper Cone Woofer 4 Ohm


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I’m not sure how accurate the Parts Express cabinet size recommendations are but it’s a starting point.

Parts Express Staff Recommended Enclosure Volume​

Sealed Volume0.682ft³
Sealed F364.72Hz
Vented Volume2.98ft³
Vented F325.51Hz
So, is there a reason to use a folded Voigt pipe it transmission line for the woofer cabinet??? Here are the speaker specs.

Product Details​

BrandFactory Buyouts
Part Number299-4004
Unit of MeasureEach

Product Specifications​

Nominal Diameter8"
Power Handling (RMS)80 Watts
Frequency Response40 to 4,500Hz
Sensitivity86.98dB 2.83V/1m
Voice Coil Diameter1.5"

Thiele-Small Parameters​

Resonant Frequency (Fs)53.16Hz
DC Resistance (Re)3.16Ω
Voice Coil Inductance (Le)0.292mH
Mechanical Q (Qms)4.548
Electromagnetic Q (Qes)0.9746
Total Q (Qts)0.8026
Compliance Equivalent Volume (Vas)0.7393ft³
Mechanical Compliance of Suspension (Cms)0.325mm/N
BL Product (BL)5.46T·m
Diaphragm Mass Inc. Airload (Mms)27.559g
Maximum Linear Excursion (Xmax)5mm
Surface Area of Cone (Sd)248.16cm²

Materials of Construction​

Cone MaterialPaper
Surround MaterialRubber
Voice Coil Wire MaterialCopper
Voice Coil FormerAluminum
Basket / Frame MaterialSteel
Magnet MaterialFerrite

Mounting Information​

Overall Outside Diameter8.75"
Baffle Cutout Diameter7.25"
# Mounting Holes4

Parts Express Staff Recommended Enclosure Volume​

Sealed Volume0.682ft³
Sealed F364.72Hz
Vented Volume2.98ft³
Vented F325.51Hz
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I also came across this post from 2007 from philthien on Tech Talk.

Fried made several versions of Beta speakers, and one of them used two smaller holes (maybe 1/2") in the baffle as aperiodic vents. I imagine the backs of the holes was covered with some material. But I guess you don't have to worry about port noise so you don't need to go overboard on size. I have heard Beta speakers and was amazed by the bass coming from such a small package.

I'm including a pic.

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This will be in interesting experiment.

From the P.E. Site they recommend—-
Sealed Volume of 0.682ft³
Sealed F3 of 64.72Hz
Vented Volume of 2.98ft³
Vented F3 of 25.51Hz

So where would an Aperiodic Vented cabinet end up for volume and F3???

And, how do I determine the volume?
Joined 2001
Paid Member
Fried made a bunck of aperiodic loudspeakers. The R & The Q were standout. Essentially a box with a substantial slot vent filled with foam rubber (i think they could have used better, looked like it could have been a slice from a foam mattress).


Never saw a Q with such nice veneer, the ones we had were cosmetically similar to the bigger R.


Joined 2001
Paid Member
Gotta go turn on my modeling computer.

The Qt is high. Hgher than the max flat Q = 0.707. Any box will push that higher.

An aperidoci box (a controlled leakage sealed box) will lower the Q somewhat.

So the reciepe is, a box as large as you can live with and make it aperiodic.

Or sealed, with EQ (Linkwitz transformish thing), but requires extra power & excursion.