Prototype(1+2)SuperLoud P.A.

Prototype(1+2)SuperLoud P.A.


Project Category:
Portable Speakers

Project Level:

Project Time:
8-20 Hours

Project Cost:
$100 – $500

Project Description:
Prototype portable P.A. and D.J. speakers. Super loud and clear midbass and highs. All speakers and electronic parts supplied by Parts Express. Best used with a subwoofer crossed over @ 120Hz.

Design Goals:
Small, light, high power, super loud, super smooth, musician’s & D.J. speakers. Features: Shimmering projected highs (even with this piezo!). Super tight mids & midbass.

Driver Selection:
Horn: Goldwood GT-1025. Mid driver: Eminence Alpha 4″-8ohm. Midbass: Dayton Audio DS-115-8ohm

Enclosure Design:
12″x7″ sealed enclosure, isolated midrange and midbass.

Enclosure Assembly:
I had a good time making these. It took a while. They kick-butt.

Crossover Design:
Tuned by ear, tried to keep phase shift in mind. The mid & highs are time aligned the midbass is not. 4.7uF cap to horn. .33mH coil & 33uF cap to mids. Midbass (lower spk) is straight signal in.

Tips & Tricks:
Use with powered subwoofer for total kick-buttness.

They kick-butt. The high-end audio cap took away the rasp from the horn. The sealed midrange rolls in at 600Hz and out at 4.7kHz with the coil. The mid reflector plates (reminiscent of the Altec A-7) project mids far. The midbass hits hard and is a straight line in. I don’t hear any distortion and the time alignment can’t be detected. These are 8 or 4 Ohm cabinets.
These are prototypes and many more improvements will be added.

About the Designer:
Lawrence Sepulveda (L.S. Audio) Machinist, electronic technician, musician.

Project Parts List:

Goldwood GT-1025 3″ x 7″ Wide Dispersion Piezo Horn Mid/Tweeter
Eminence Alpha 4-8 4″ Full-Range Pair 8 Ohm
Dayton Audio DS115-8 4″ Designer Series Woofer Speaker
Dayton Audio 0.33mH 18 AWG Perfect Layer Inductor Crossover Coil
Acousta-Stuf Polyfill 1 lb. Bag Speaker Cabinet Sound Damping Material
Dayton Audio PMPC-4.7 4.7uF 250V Precision Audio Capacitor
33uF 100V Electrolytic Non-Polarized Crossover Capacitor


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  1. 1
    Timothy Girard

    When I was a young musician, I actually purchased a pair of mint condition Altec A-7 ‘Voice of the theater’ from a old movie house. I promptly ruined them with paint and new drivers. I feel like building your little version might redeem me a little bit… Besides that, they’re freaking cool looking

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