Subwoofers are basically designed to reproduce and deliver output at bass frequencies. In this article, we focus on the tapped horn subwoofer designs.
A tapped horn subwoofer is one that has a horn that expands along its length and is configured such that the driver radiates energy into the horn’s throat. There is also a tap where the other side of the same driver’s cone radiates into a portion of the horn typically near the mouth/exit.
To explain another way:
A tapped horn subwoofer is one that uses bass radiation from both the front and rear of the driver and combines them at the mouth. This results in greater efficiency, smaller enclosure size, and deeper extension (the distance a woofer moves from rest). The acoustic load on the driver also leads to a lower excursion which then leads to increased maximum SPL and lower distortion
The advantage of using a tapped hirn subwoofer is that tapped horns are good when you are working on a budget and money for drivers and amps is limited. They are also good choices when you need maximum output loudness.
The disadvantage of tapped horn subwoofers is that there is a requirement for DSP filtering to prevent overload at the lower frequencies and remove high Q peaks just outside the pass band or risk a flat response.
What Is A Tapped Horn Subwoofer?
As the name suggests, a tapped horn subwoofer is a subwoofer designed in a way such that the radiations from the rear and front drivers combine, or in a way, are tapped at the mouth of the subwoofer.
The idea has only been brought to light by Tom Danley, though still remains very obscure.
Benefits of Tapped Horn Subwoofers
Please see below the list of the advantages of tapped horn subwoofers:
- Greater efficiency
- Deeper extension
- Smaller enclosures
- Lower excursion (the distance a woofer moves from rest)
- Increased maximum SPL
- Lower distortion
Tapped Horn Subwoofer Plans
There are many tapped horn subwoofer plans as there are subwoofer manufacturers and DIY sub-box designers today. Some of the most common tapped horn subwoofer plans include:
1. Eminence Tapped Horn
This is a large 20 Hz tapped horn for 15-inch drivers. The most suitable drivers for this plan are the obsolete Eminence EPS15-500 and the current Kappalite 3015LF, DEFINIMAX 4015LF, or MTX Audio T7515-04.
2. 30 Hz Tangband Tapped Horn
The mini Tangband tapped horn subwoofer has a small 4-times folded tapped horn. The plan fits a 6.5-inch Tangband W6-1139SC or W6-1139SG. An alternative plan to the 30 Hz Tangband is a 6-times folded version provided by Martin.
3. 30 Hz Mivoc Tapped Horn
Developed by Volker, the 30 Hz Tangband tapped horn plan works well with the budget 10-inch Mivoc AWM104. The plan is estimated to deliver a free air resonance of about 31 Hz at 9mm Xmax.
4. 38 Hz Tangband Tapped Horn
This is a 6.5-inch tapped subwoofer plan for Tangband W6-1139SC or W6-1139SG. It goes less deep but extends further up.
5. 38 Hz Double Folded Tangband Tapped Horn
This is also a 6.5-inch tapped horn subwoofer plan. It is suitable for Tangband W6-1139SC or W6-1139SG. The plan uses similar parameters as the 38 Hz Tangband tapped horn with the only difference being that it is folded and less tall.
6. Conical Midbass Horn
This 77 Hz conical Midbass fronthorn is designed to fit an Electrovoice EVM15L. The plan has a 500 cm2 throat area (22.4 x 22.4) cm. the horn length is 77.3 cm and the mouth area is 2978 cm2 (45×66.2) cm.
7. Tactrix Midbass Horn
This is a 150 Hz Tractrix Midbass front horn subwoofer plan that is meant for the Electrovoice EVM12L driver.
8. Tractrix Midrange Horn
This subwoofer tapped horn plan is based on Dr. Bruce Edgar’s Midrange horn article. The design covers a wide range of frequencies from 500 Hz to 5 kHz. It works well with JBL LE5-2 with a speaker offset of 1/4 inch from the baffle. According to Dr. Bruce Edgar’s article, the gap should be filled with air previous foam rubber.
9. Klipsch Corner Horn
This is a Klipschorn plan adapted from the 1995 Klipsch design and adjusted accordingly. It fits 15-inch bass drivers.
10.10” Lascala Midbass Horn
The plan is also based on the original LaScala. It is however shrunk down by a factor of 0.67 in order that it fits a 10-inch. It delivers midrange better than midbass frequencies.
Other tapped horn subwoofer plans include:
- 15” Tapped Horn EASY subwoofer
- Tapped horn D18/Subcoop D18 Plan
- William Cowan’s 18 Hz tapped horn subwoofer plan
- William Cowan’s 30 Hz tapped horn subwoofer plan
Tapped Horn Subwoofer Designs
There are several tapped horn subwoofer designs that are efficient and up to the task. Some examples included:
- Dual 18 Tapped Horn Design
- Danley Tapped Horn Subwoofer designs e.g., TH115, TH112, TH212, TH412, TH812, and THSpud
Tapped Horn Subwoofer Kits
Based on the several tapped horn subwoofer plans and designs, you can assemble various kits for a tapped horn subwoofer. Some of the speaker kits you can use include:
- Selected speaker chassis
- Quality screw
- High-quality crossover components
- Detailed blueprint for housing and crossover
Depending on the kit you have, you will need:
- Electric wire
- Bass reflex tube and insulation material
It is an inconspicuous monolith that is full of dynamics. Surprisingly, the subwoofer works pretty well with the six-inch model (Omnes Audio SW6.01). You can buy the required wood from a carpenter of your choice or from well-stocked hardware.
8” Tapped Horn Subwoofers
An excellent example of an 8-inch tapped horn subwoofer is the Monster 8” Diameter Units. It is an 8” tapped bass horn monster woofer from PMR and is a super subwoofer with low QTs, low Fs, high excursion, and high output.
With SAVAGE 8” drivers, they are great Hi-Fi units that sound fast, tight, articulate, and colorless.
18 Tapped Horn Subwoofer
Here are some of the 18 inch tapped horn subwoofers:
- THAM 18 – 18” Tapped Horn
This is a Johannes Robin subwoofer design. The build is 18mm plywood and the outer dimensions are 600x800x650. It works well with the B&C18TBx100 driver.
- Danely THE TH118 Tapped Horn 18 inch Subwoofer
- Martin Audio WLX 18” Horn subwoofer
12 Tapped Horn Subwoofer
12-inch tapped horn subwoofer designs also deliver quality audio performance based on the different use scenarios. Some of the best 12” tapped horn subwoofers include:
- MTH-30 12” tapped horn subwoofer
- VTC Pro Audio ELS212T Dual 12” tapped horn touring subwoofer; this is available in fixed and touring installation Versions Excellent for all throw distances low distortion with very high SPL, high clarity, Definition & Punch Advanced DLMS4080 Digital Loudspeaker management system.
10 Tapped Horn Subwoofer
10-inch tapped horn subwoofers are much smaller but still very efficient. A good example is the Danley DTS-10 tapped horn subwoofer.
Bass Tapped Horn Subwoofer DIY
An eight-foot-tall bass horn loaded with an 18” subwoofer is an excellent example of a bass-tapped horn DIY subwoofer. It is adapted from the William Cowan design but runs corner to corner as opposed to William Cowan which runs side to side.
DIY Tapped Horn Subwoofer
Building a DIY tapped horn subwoofer is not a detailed process. In fact, most DIY projects are adapted from existing ones with minor adjustments. You can quickly try a DIY tapped horn subwoofer or have it done by your local carpenter to your preferred specifications.
Folded Tapped Horn Subwoofer
Folded tapped horn subwoofers have the back of the sub placed closer to the horn. This way, the backward motion of the woofer produces a sound that augments the sound produced by the forward motion through the horn.
Folded tapped horn subwoofer designs are commonly used in tweeters and midrange subwoofers. This is generally because lower frequencies have longer wavelengths and require longer horns.
They combine the “megaphone effect” of the horn with the “rearward subwoofer travel sound utilization effect,” making them more efficient. A good example is the Wolfhorn SDX folded tapped horn subwoofer enclosure.
Small Tapped Horn Subwoofers
Small tapped horn subwoofers are similar in plan and design to other tapped horn subwoofers. They are however smaller in size.
Horn Subwoofers vs Tapped Horn Subwoofers
Unlike normal subwoofers, tapped horn subwoofers do not require a large mouth exit to have a flat response in the pass band region of the frequency range. This is why a properly designed TH can have a flat response within its passband.
In addition, tapped horn subwoofers use the radiation from both the front and rear of the driver and combine them at the mouth.
In addition, tapped horn subwoofers offer about two octaves over a flat response which means they are subwoofers and not woofers.