The Hyperion is a small two-way bookshelf speaker that employs the Hiquphon OW I fabric dome tweeter and the Peerless 6.5" HDS woofer. They are very similar to the Dillon Acoustics Metaphor speaker design which uses the same drivers. I went a bit overboard with the cabinets and they are very solid. The Hyperion was my first attempt at designing a speaker by myself with the help of Speaker Workshop and my measurement setup. In the end I concluded that the woofer filter for the Metaphor design was hard to beat and "borrowed" it for my design.


Hiquphon OW I
Excellent frequency linearity 2 - 20 kHz +/- 1 dB typical
Excellent phase linearity
Smooth roll-off at high frequencies
Low and well controlled resonance frequency
Well controlled damped low frequency response, soft raising
Very broad-banded (2.0 kHz to 27 kHz)
Fast transient response
Very low distortion
A-periodic damped moving system
Exponential phase-correction horn-loaded
Saturated magnet gap for low magnetic distortion
Perfect sealed housing
Heavy duty connectors for 2.5 mm2 lead wire
Excellent, mechanical robust, non-vibrating, soldering contact
Shock absorbing construction
Matched pairs within 0.5 dB in frequency range 2-20 kHz (OW types only)
Beautiful sound capabilities

Peerless HDS 6.5" woofer (850439)
A high End mid-woofer with rigid aerodynamic cast aluminium basket profile and ventilated spider. The cast basket provides the necessary sturdy base for the magnet structure and suspension and allows for long excursion of the cone. The spider is ventilated to achieve the lowest possible compression and to allow air to flow freely to create a cooling effect for the voice coil. The design of the basket front allows for very slim box designs and the edges are chamfered to re-duce the necessary amount of counter sinking. The three or five layer sandwich cone improves accuracy and consistency of sound reproduction over the entire frequency range, creating a more "musical" driver.

Cabinet Design

The Hyperion cabinet measures 16"x8.5"x10.5" (HxWxD) and is constructed of 3/4" MDF. The internal volume is roughly 12 liters. The cabinet is heavily braced and includes a slotted port in the front. The tweeter is housed in it's own cavity which helps to isolate it from the woofer and the front baffle is reinforced on both sides of the tweeter to further reduce vibrations. The internal walls of the cabinet are lined with 1.5" convoluted foam to reduce internal reflections. I chose to use a 1/2" roundover on the front baffle to reduce baffle diffraction effects. For this particular pair I used some very nice quilted maple veneer with satin polyurethane.

Crossover Design

The Hyperion utilizes a basic parallel crossover network in a 4th order Linkwitz-Riley configuration. During the design phase I also came up with a series version which approximates the parallel network with similar slopes and crossover point. The sound is very similar between the two designs but there are a few minor differences. The parallel network seems to have a more focused center image while the series network provides a more spacious soundstage. With regards to tone the two designs are almost identical. In the end I chose the parallel network primarily because it uses fewer parts overall.


Below is a plot of the ungated farfield response for the Hyperions. This measurement includes the effects of room reflections which appear below 500 Hz and result in exaggerated peaks and dips in the response. Overall the response is pretty flat, within +/- 2dB across most of the frequency range. The dips and peaks in the 2-5kHz region are primarily due to cabinet diffraction effects and are less severe off-axis. Their efficiency is around 85dB at 1 meter which is average for a typical two-way design with extended bass response.
The Hyperions are a great all-around performer and sound great with just about any type of music. The Hiquphon OW I tweeter is exceptional and provides a very spacious and airy top-end. The Peerless HDS woofer is surprisingly clean and detailed considering it has a poly-based cone. They don't have the detail of a stiff cone (aluminum, magnesium, etc.) but this makes them sound great will all source material because they are not over-analytical and don't reveal every little defect in the recording. Despite the excellent value and performance that the Peerless HDS driver provides, I tend to prefer the added detail and depth that the Vifa XT woofer offers in the Asterion design. Imaging is decent but not as nice as the Proteus jrs. A complete pair of Hyperions can be built for just under $500 which isn't bad considering their exceptional performance.

Speaker Workshop Project File

The Speaker Workshop project file for this design is now available for download: Hyperion.swd. This project file includes gated measurements for the drivers at different listening axes (TA stands for "Tweeter Axis" and BT stands for "Below Tweeter"). There's also a crossover network simulation based on measurements taken on axis with the tweeter. The file is about 3.7 MB so be patient if you have a slower connection.