Wormhole 9 Octaves Wideband

[Joachim Gerhard]

My design reminds me a bit of this :

Georg Neumann GmbH - Professional Monitoring

We called this type of speaker " Abhörschrank ".

Loudspeakers in the 60th where still big and around 100 liters of volume was common.

 

[Joachim Gerhard]

Here are other examples of the type of speaker i will show.
One is a Dieter Rams design ( Braun ) from 1959, the other is from the ex. DDR, around same time.

 

[Joachim Gerhard]

RCA used that kind of speaker too.
Here you see Lenny Bernstein listening.
https://www.youtube.com/watch?v=xTfNMgrcnZU

 

[Joachim Gerhard]

Here is a picture of the RCA speakers.
Why do i show you this ?
It is beacuse they all have in common that they are wide and high but not very deep.

 

[Joachim Gerhard]

Here are some pictures of my prototype.

 

[planet10]

Joachim,

Is that horizontal surface bamboo ply?

dave

 

[Joachim Gerhard]

Yes, this is Bamboo ply. Besides Panzerholz it is the best wooden cabinet material that i know of. The Bamboo is around 25mm, so rather substantial and the cabinet is not braced.
I have put damping pads in strategic places though and i experimented a lot with acoustic damping.
It is a reflex design with a down firing port. This drives has intersting parameters so i could put the reflex resonance at a deep 30Hz. It is abit overdamed though to compensate the room gain a bit.

 

[Joachim Gerhard]

The top and bottom are from 25mm spruce ply. I use this rather soft material in a desire to damp culminating resonances. The finished version will have a granite plate on top instead of the block you see now.

 

[planet10]

You will find that the vertical surface grain ply is even better and better yet the version with stranded surfaces.

This is the Neopilitan variety (plyboo's name). A little garish for some, also available in natural and carbonized.

dave

 

[Joachim Gerhard]

I used this pads in strategic places :
https://www.intertechnik.de/Shop/Zubehoer/Daemmen-und-Daempfen/_WOTUMEX_1768,de,16,154489

 

[Joachim Gerhard]

Interesting material . So much choices today.

 

[Joachim Gerhard]

I use this for damping :
https://baustoffe.koempf24.de/isove...9dVOo_5ZOxfk&gclid=CNqroOXRjsoCFUHkwgodjb8PNg
I know, some people may be alergic to it and it has a reputation to provoke scratching.
I did not have much problems with this. The material seems to be much improved over older varieties and it works better in this cabinet then other options.
I think it is beacuse it is more dense and has a bigger surface so it also damps in the lower reaches. I really went for maximun natural fundamental tone in this.

 

[bear]

Olsen showed curves for his baffle variants - back to the dawn of hifi!

But Joachim, you are following a path that I fully agree with in principle regarding the baffle... of course people have wanted tiny "mini-monitors" for so long now...

_-_-bear

PS. I just now acquired a pair of Quad 57 speakers... my ears are very happy-happy.

 

[planet10]

Olsen

Olson. Easy to mis-spell.

I can't remember how many sets of Quad 57s i've had… a love/hate relation. A good friend has a triple stack in his room.

dave

 

[Joachim Gerhard]

I had Quad 57 and Quad 57 double in a Mark Levinson HQD system.
I had the modified Kelly Ribbons and 2 x 76cm Hartley woofers in 1500 liter cabinets.
No idea how i got that money together when i was 22.
I still have a refurbished ESL63 from Stein Music.
One of the advantages of a wide baffle is the avoidance of the baffle step.
That alone increases sensitivity where is really matters by at least 4dB.

 

[Joachim Gerhard]

Some think that only a slimm speaker can throw a soundstage that makes the speakers " disappear ". A good example is the ProAc Tablette. That works best in the nearfield i think.
Curiously enough the speaker that i show here has one of the best imaging i ever heard.
I even hear sound over my head and left and right from the speakers when that information is on the record. I sit around 2.5 meters away and the speakers are placed ca. 3m from each other. Nevertheless there can be a strong phanton source in the
middle. I mean i made my income with slim speakers so i should not complain about them.

 

[ponger]

What are the components on the floor, and the box on top?

 

[planet10]

Some think that only a slimm speaker can throw a soundstage that makes the speakers " disappear ".

These image well and disappear:

And they are fairly wide

At the frequencies that cause problem diffraction the 8" will be "beaming".

dave

 

[Joachim Gerhard]

Hi ponger !
On the floor are EQ components. Most wideband speakers have a peak in the upper presence region around 3.5 kHz and this components flatten the response.
It is not a crossover as such.
The block is just a granite weight. It will be substituted with a plate.
Nice speakers Dave. That shape also works very well.

 

[Joachim Gerhard]

I build wide and high speakers before.
For example i copied the shape of the Boston A400 in my Quintessential German Speaker of the 70th.
They image well too.