OneSound – loudspeakers design and tuning

DESIGN IDEA

All started from the idea of a wide band speaker. I wanted to make a quick verification of how this may sound. 

I took into consideration a couple of speakers but I wanted to make it a quick project. One day my friend invited me to his house. This is a well known speaker designer. I was listening there to Fostex FE126En in a 2 way construction. I was shocked about the bass, mids and treble. This is how it started. 

What wide band speakers can give you? One speaker is covering the whole frequency range which means no phase issues when joining SPLs of multiple speakers, usually high sensitivity, easy to drive impedance. 

DOWNSIDES of wide band speaker:

  • ringing when playing loud at high frequencies
  • very very bad directivity – meaning you can hear sound above 10kHz sitting in one position only. Do not move your head!

DRIVER’S SELECTION

As always I analyzed different options for wideband before purchase. 

Expectations: 

  • high efficiency over 91dB/1m/1W
  • 8 Ohms

Short list:

  • Fostex – good price but only cone material is interesting, MMs 3g and that’s it. Everything else like motor, metal basket just basic. Easily available.
  • Alpair – great looking driver. Not so easily available in Poland. Technologies more advanced than Fostex (aluminium basket, demodulation ring). But there are some cons like the cone should be treated very carefully, long time to break up, some limits in power when using.
  • Tang Bang – mostly low efficiency drivers

Final selection and reasoning:

  1. Wideband

Fostex FE126NV

92dB / 1W / 1m 8 Ohm

http://feleppa.com.au/speakermeasmid.html

Looking on the directivity and first measurements

  1. Tweeter

SEAS 22TAF/G (H1283)

Cheap, nice and recommended by many designers. Worth money, giving a lot! Above that 92dB/2,83V/1m 6 Ohm which is 90,5dB / 1W / 1m. This is the selection criteria.

  1. Bass

ETON 11 612

https://www.hifitest.de/test/lautsprecherchassis-tieftoener/eton-11-612c850-rp-14326

I bought it by accident. But it goes with my criteria: shallow, high sensitivity.

Xover:

Tweeter – Mid = 4,5kHz

Mid – Bass = 100Hz – 170Hz

Mid cabinet = 5,5l (closed 178Hz -3dB; 98Hz – 3dB vented)

Bass cabinet = 34l

Bass reflex 

BR size 10x30cm

BR size 10x37cm

BR size 10x100cm

FINAL RESULTS

SPEAKER MEASUREMENTS

BASS

I tried to measure in house (no anechoic chamber) the bass speaker that is on a side. No way to do it in a reasonable way. This means that aligning in phase can be done only by accident. This is not my style of designing. I gave it up.

Measurements results:

red = 0 deg – meaning that the bass driver is on the side baffle and it is 90 deg away from front baffle and speakers

white = 30 deg

green 60 deg

yellow = 90deg

7dB higher efficiency from 90 deg to 0 deg

WIDEBAND – Fostex

Build process:

Final results:

Measurement of final speaker with passive crossover