----- Build your last loudspeakers yourself -----

 

 

What's new

 

Concepts

Stereo Recording and Rendering

Audio production

Loudspeakers

Crossovers

Room acoustics

Issues in 
speaker design

 

 

Projects

LXmini

LX521
reference

ORION
challenge

ORION-3.4

PLUTO-2.1

WATSON-SEL

PLUTO+
subwoofer

THOR
subwoofer

PHOENIX
dipole speaker

    Dipole models

    Active filters

    Microphone

     FAQ

Three-Box active
system (1978)

Reference
earphones

Surround
sound

Loudspeaker
& Room

 

 

Assemblies

LX521

ORION

PLUTO

Do-It-Yourself

 

 

Resources

Publications

Sound recordings

Links

Other designs

My current setup

About me

Site map

 

 

Conclusions

 

 

HOME

 

--------------------
ORION
PLUTO
LX521

Users Group

 

 

--------------------
Digital Photo
Processes

 

 

What's new

 

 

Introduction
Design
 
Construction
  

Amplifiers

Digital System
Gallery

 

    Introduction

                

The LX521- Reference Loudspeaker has received much applause from music lovers all over the world. But it has also caused disappointment because it requires a fair amount of space and breathing room, which many housings do not provide. On top of that the LX521 is too expensive for many and/or its acoustically defined shape is not pleasing to someone in the household. Such objections are particularly aggravating, when the near life like sound volume capability, for which the LX521 was designed, is neither wanted nor could be tolerated in the given living space, or if they were willing to give up bass below 45 Hz for a much smaller loudspeaker.

In the past I would have recommended to build PLUTO 2.1 instead of the LX521, but now the LXmini will exceed what PLUTO 2.1 had to offer and be a true alternative to the LX521, except for the bigger speaker's extended bass. The low frequency portion of the LXmini's frequency response is similar to the PLUTO's. With a 700 Hz LR2 crossover to a small, full-range and open-baffle driver, and with a diffusing as well as attenuating structure for controlling the rear radiation, the polar response tends towards cardioid behavior and reduces reflections from objects behind the speaker.

With directivity controlled in this way the LXmini becomes much less sensitive to room placement, while also gaining in 3D imaging precision. The small, full-range driver on top is superbly smooth and detailed. It blends flawlessly with the pistonic, infinite transmission line woofer for a completely neutral sound in a reverberant room. The speaker stands 40" (1 m) tall. It requires two stereo power amplifiers of 80 W for woofer and full-range drivers. The four input signals to the power amplifiers are generated in a miniDSP 2x4 processor from the left and right outputs of a preamplifier or other device with a volume control. 

The LXmini is a most remarkable loudspeaker. It converts electrical signal voltages into acoustic pressure variations, which are perceived as completely neutral and detailed even in a reverberant environment. With this design I want to give every music lover the opportunity to build and enjoy a reference quality sound system singing in their own living space.

 

... and challenge the Loudspeaker Industry worldwide!

At the ALMA International Winter Symposium in 2014 I gave a presentation with the title "Whatever happened to the quality of reproduced sound in the home?" and earlier I had given a paper "My search for the ideal stereo loudspeaker".  It has been no secret to industry insiders that little progress has been made over the last 50 years in rendering a convincing auditory illusion via two loudspeakers in a domestic size room. Today surround sound is being pursued without having realized the potential and perceptual realism, which 2-channel stereo is capable of. The recording industry has of course contributed to this situation by a multi-microphone sound pickup and pan-pot-mixing work flow. The acoustic cues for the spatial relationship between sources and their reverberant environment are avoided or artificially generated. Yet all naturally occurring sounds exist in 3D space and our brain has evolved exquisitely to hear in 3D and not be fooled.

The loudspeaker industry has developed excellent electro-acoustic transducers over the last 50 years, but when put in boxes of various shapes and sizes in order to send a flat on-axis signal to the listener and illuminate the room appropriately and without spurious emissions from the speaker, then progress has been marginal at best. The LXmini is an example of what can be done with state-of-the-art transducers in a powered 2-way speaker system to generate an appropriate radiation pattern. It could not be done with passive crossover/equalization in any practical way. Using a digital signal processor makes equalization of transducers and power division very easy, once the acoustic design has been established for 3D radiation.

Actually, the weakness of today's speakers is primarily their acoustic design. I do not need to name manufacturers. Exceptions are rare and insignificant in terms of market share. For the lack of progress I would also blame equipment reviewers of the various audiophile magazines, because in the end they are the gate keepers and usually beholden to the magazine's advertisers. 

If each manufacturer would build a pair of LXmini's as reference for their product development to hear in which way they exceed or miss its performance, then real progress might be made. Each equipment reviewer should build a pair of LXmini's as reference to compare other speakers to and to describe in a perceptually meaningful way the differences between sound systems as experienced in their unique and shown listening environment. Since it is not difficult nor costly for consumers to build the LXmini as their reference, they would then know what to expect from a loudspeaker review. 

I am not saying this because I think the LXmini is the ultimate sound quality reference, but because the LXmini defines a standard of excellence that top of the line loudspeakers should meet or exceed and be recognized for that by reviewers and consumers.

 

********************************************************************************************************************************

What you hear is not the air pressure variation in itself 
but what has drawn your attention
in the two streams of superimposed air pressure variations at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space
Have they been recorded and rendered sensibly?

___________________________________________________________
Last revised: 09/15/2014   -  1999-2014 LINKWITZ LAB, All Rights Reserved