Aino gradient - a collaborative speaker project

[Patrick Bateman]

Thank you for your interest an comments & ideas! This is a long thread with many evolution stages of AINOgradient speakers.

A long story made short about AINOs...

The basic consept is copied from 1980's Jorma Salmi design Gradient 1.x series - a very good review here The Gradient 1.3 Revisited

I studied Linkwitz and Kreskowsky homepages and got personally helped by Rudolf Finke. Minidsp and REW made all this possible for me and are key factors in multiway dipoles for dummies! The shape of bass module comes from a very popular glass by Aino Aalto, wife of architect Alvar Aalto. My daughter and grandmother are also named Aino.

Acoustically Ainos are monopole below 100Hz, cardioid 100-300Hz, dipole from up there (highest dipole null around 6kHz) In early stages I struggled with rearside radiation anomalies of cone drivers and reflections from the large magnet of Fountek Neo3.H. These were fixed by using B&G Neo8 and Neo3 planar units. Another great struggle has been indoor measurements, remember the weather here in Scandinavia!

For the last 9 months I have only made minor adjustments in minidsp settings, mainly to optimize acoustic responses of each driver and tonality of the system. I am very happy with the present performance, and so were the people at the Finnish diy-audio event - AINOgradient got the nomination for "Best Sound in the Show"

Here indoor-measurements at 1.5m distance. RTA/steady state response in-room is 16Hz -18kHz in a slightly descending (ideal) room curve. The upper end is limited because of Icepower D-class amplifier's input-impedance problem (but my aged ears don't hear that)

Link is dead, attached is the article courtesy of wayback machine

 

[Juhazi]

I finally had time to make vertical directivity measurements!

Angles estimated with 5 deg steps up to 30 degrees. Indoor with quite many disturbing reflections, so I will show only smoothed 4ms gated measurements. Lower limit in graphics is 200Hz, keep that in mind when looking and comparing to other similar from eg. ASR or Erin's Audio Corner

Present eq-xo is done with Minidsp 2x4HD using parametrics (not FIR). Slopes are basically LR2 but with elliptic tails. In v35 lowest xo is 150 Hz, second 600Hz, then 4500Hz. Previous v33 has higher SW and WM xo. Peaking above 10kHz can be eq'd easily, but it's not disturbing to anyone.



4ms 1/3 smoothing 100-20 000Hz



9ms 1/12 smoothing 20-20 000Hz

 

[Juhazi]

Room response of the left speaker, v35

 

[Juhazi]

Room response of both L and R playing one by time, 500ms MMM

Right speaker's planars seem to be 5dB quieter - I must check settings and most likely lift their gain. Amp modules are similar and positioning is mirror image practically.

 

[Juhazi]

It's been raining... edited to version 36

 

[Juhazi]

Updated presentation, link

 

[Juhazi]

More VCAD tables from latest indoor measurements, measured angles only to 30deg hor and vertical. 9ms gating, 1/6 smoothing. Freq starting from 100Hz, same scales.

 

[hifijim]

It has been several years since I read through your presentation. nice ! Thanks for the link.

Can you discuss the ramifications of tilting the 12" dipole driver ?

 

[Juhazi]

Tilting is based on several important things...
1 It looks better
2 That's how Gradient 1.3 has it
3 It might reduce floor bounce
4 It makes less torque to support points