Attention Raffi and Till (Roemhild)

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#41
Hi Tyimo, nice to see somebody else looking at those older impulse Horns. There was a little discussion about them here a few months back. The layout of them is unusual in that they do have a large filter chamber but it is the whole height of the enclosure, tapering from wide at the top, though not evenly, down to narrow at the bottem which becomes the throat. The horn is then directed up to the top, turns over and comes back down to the bottem like an upturned BIB but not as long. Probably a quarter wave. The mouth at the bottem, full width and deth of the enclosure almost, then appears to be 3 - 5 cm above the ground. Is this mass loading the horn? Does the layout of three folds full height in the box have some sort of resonating effect? The three folds are the filter chamber and the two horn folds. Seems to have been very impressive at its time.
 
#44
Hi Tyimo,


to be sincerely, I have no plan if this horn works and why it should sound very good. Dont understand me wrong I belive you that they sound good. I have heared a lot things that shouldn`t work but they do and that very good too.

Here is my simulation with your parameters:

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



From my point of view the chamber is a bit too small.

scottmoose has given a good answere. It is a thing between a BL-Horn with a big chamber and a usual BR. I would call it a HornReflex.


Here you can see 5 different way how I simulateted one driver.

Black Line is a usual BR
Green Line is a BL-Horn with 1m lenght and a 3200cm² opening area.
Blue Line is a "regular" BL-Horn with a chamber of 3 ltr.

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



As you can see there is now real differece between a BL-Horn with a big chamber and a BR.


sorry for my late response


greets Till
 
#45
Hi Till!

Thanks for the simulations. I got the same with the MJK's Mathcad sheet.

I have heared a lot things that shouldn`t work but they do and that very good too.
Click to expand...

Yes, I think this box is in the same category.

I have an idea about the heard good bass reproduction.
Philips used it in little "sub"bass-boxes: they tuned the box to strong 80Hz reproduction because they said the human ear and the brain will add to the missed lower frequencies. Forexample: We here in the reality strong 80Hz and the brain will imagine that also some 40Hz and even 20Hz was played!

Sorry for my bad english. I hope you can understand the basic "psicho-acoustic trick".


Greets:

Tyimo
 
#48
Hi Tyimo,


right now I have got a single-ended-class A MosFet amp (similar to a Pass Aleph)

my new project is a 6-channel amp with the Aleph-X. I have 6 of the PCB's out of the diy-audio group buy.
I will use them for a full active system ( one amp for the tweeter, one for the midrange and one for the woofer).




greets Till
 
#52
planet10 said:


It can be modeled with Martin King's software. I have been working with Scottmoose on a family of BVRs and that is what he is using (BVR = Big Vent Reflex = Replikon-style box)

dave
Click to expand...


Hi Dave,

you are 100% right. I allways said that for me a BL-Horn is nothing else than a BassReflex. In my way of building BL-Horns I can shorten the horn and reduce the opening area without any bigger differences. Only the sound will change a bit. I personaly like BL-Horns (or name them BR with a big Port or HornReflex or how ever) more than a BR.

In this simulation you can see what I mean

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



the blue line is a "normal" BL-Horn





Tyimo said:
Hi Dave!

Thanks!



Yes I know and I did it already, but I would like to know is it possible to modify the original Helmholz resonance's equation fo this kind of duct shape????

Tyimo
Click to expand...


Hi Tyimo,

I have no formula for that but if you make the hornmouth bigger you have to make the length and throat bigger too.


greets Till
 
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