The Advantages of Floor Coupled Up-Firing Speakers

and not just that - also cardioid radiation pattern

When I tried cardioid designs for the midrange, I could never get around the over-damping effect of the pressure-release in a small volume "enclosure".

It always seem to "suck the life" out of the drivers, and blunt spatial aspects. Yet when I read the reviews, somehow the designers have overcome this..

-peaks my curiosity.
 
to understand Helsinki 1.5 it is useful to take a look at their precedessors in the Gradient line

first of them all were Gradient 1.1 or 1.0:

An externally hosted image should be here but it was not working when we last tested it.


more: Myydyt kaiuttimet - Classic Audio

take notice of a much bigger midbass unit, operating as a dipole in the range of 250<1500 Hz, its acoustical center closer to the floor than in the case of Helsinki

in fact all the subsequent models in the line (1.2, 1.3 etc.) used the same configuration, Helsinki is the first to employ a smaller midbass in a cardioid enclosure
 
One of the inventions of 1.3 was to use the 15" driver at frequenciens where it shows remarkable directivity! This added to dipole function and upwards tilt... The tweeter section is a line array configuration with gradual low-pass, also giving more vertical directivity. The bass is downfiring, thus giving no floor reflection but utilizing floor boost!

A genius' work of art! 35 years ago!

It is my dream to clone this and utilize minidsp
 
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^^ is this rebirth worthy of an own thread? I´d like to participate!

I don't have skill and measuring system to make a xo myself, it would be a pleasure to participate in a project like this. I have listened to a pair of 1.3s quite a lot at my friend's some 14 years ago. I could buy originals but "signature" remake with modern technology and knowhow would be more fun!
 
What is your recipe of the ideal ?

I believe that floor reflection must me attenuated and low-passed as much as possible
I also believe that (and this belief seems to have been confirmed independently by Mr Croft research quoted earlier in this thread) - that we need a certain optimal ratio of direct to off ceiling reflected sound

this ratio depends on the speaker directivity, the angle at which it fires up to the ceiling and the listening distance

I also believe in the necessity of time-coherence in the sense of the wavefront fidelity - all early reflections should preserve the shape of the initial transient that reaches the listener as the direct sound

so I believe that we need an adjustable (with regard to the angle of orientation of its acoustical axis), controlled directivity and an essentially time-coherent loudspeaker, not time-coherent on axis like some, but in the sense stated above

in the light of the foregoing Gradient designs aim in the right direction but don't meet the above criteria as strictly as it is possible
 
Seems like you guys lolo and graaf know us Finns! :usd:

Sauna Porkka Playboys - Ace of spades - YouTube

Sibelius, sisu Kivikasvot - Tankeros Love - YouTube

great!

I don't know much about Finland and Finns, a bit about history and culture, I like Sibelius and Mannerheim and Kalevala for instance :D and Gradient, and some old obscure Finnish black metal bands :p

I know that Finns are tough people and also innovative people and I like it

but first of all I just know the good stuff :cool: and some Finns seem to know the good stuff too :cheers:
 
Seriously spoken, humppa is a dance rhythm that was developed here, it is basically polka in slow tempo Humppa - YouTube

And my favourite good stuff is this Olvi - Company

sandels.jpg



I have just made up a name for a new project speaker - "Aino gradient"

"Aino" is the most popular women's name in finnish, and the name of my youngest daughter, my grandmother and the wife of J. Sibelius
"gradient" derivates from sound dispersion physics and perhaps from Gradient 1.3 -speaker designed by Jorma Salmi

The project thread http://www.diyaudio.com/forums/mult...ollaborative-speaker-project.html#post3395680