GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Horn-Loaded Speakers
In the Thread: Midbass Horns and Real Estate.

Post Subject: YL1250 - very interesting!Posted by Romy the Cat on: 8/30/2009

Thanks, Eduardo, very interesting. The YL 75000 has no phase plug and 70Hz with 1” trout. It look to me like a conventional diver. Which beds a question: if to reduce compression with our classic drivers, loose plug off and reduce power then can we get out of them 100Hz or sub 100Hz? The 75000 did not impress me and they look conventional but the YL1250 is very exciting. They have long outer spider, looks like not the fiber reinforced but the pure plastic, the way how Vitavox did, and the back vent is damped with cotton. I presume that the damping of the back chamber might be changed with respect of the horns is used. The exile you say 4” that would make diaphragm 5”-6” or 7”-9” with outer suspension. I am not surprised to see a high curve of the cone – they need to keep it structurally firm.

What surprising is to see a relatively short voice coil! If thy has 5mm excursion ( that would be mandatory for 16Hz) then in order to keep the driver in underhang mode the voice coil need to be way longer of the voice coil shell not stat right from the surface of the diaphragm. Look, pretend that you are a first turn on the coil on the diaphragm side. You sit in nice environment of linearity saturated gap with magnetic lines are perpendicular to you. No the driver get excurted and you moive let say 3-5mm forward. There is no magnet in there and the magnetic lines are curved, so you angle under which the magnetic lines attack you are bent leading to non-linearity. So I was expected that the space between the surface of the diaphragm and beginning of the voice coil would be in bass driver MUCH larger and I was expecting to see the voice coil sitting 10mm in the magnet depth. Below is how it is done with Vitavox MF drivers, both plastic and metal.

Also, what strikes me is how simple the driver is made. Beside the diaphragm that is technologically is complex pars the rest of the driver is VERY simple and probably if someone wish to build it then it might be done for under $5K or even cheaper with electromagnet.

Eduardo, do you use or do you have listening experiences with YL1250 or with other compression bass divers? If you can differentiate between bass tone and bass pressure then what is you feeling about the tonal capacity of compression bass divers?

The Cat

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