Although I have long experimented with open baffles, I have never considered creating a commercial product based on them. These are typically too big, too cumbersome, with Wife Acceptance Factor of minus 27 or so in 1 /10 scale :)
However the sound is so engaging, so true, so natural. Every time I had some prototypes made I invited people to the attic to sit and listen. Everybody was impressed, so I said to myself 'let’s try'. Of course I talked to EMS about the need for a driver that would be suitable for the job. Having a driver in hand the journey started.
I have to admit that the open baffle project begun with solutions other than OGY or even its full range driver in mind, and this experimentation continues by the way.
As I mentioned on several occasions when I paired the OGY stand mount speaker with the open baffle for the first time, initially with one pair of bass drivers and then with two pairs, I was immediately impressed. So were my visitors.
This led to the creation of the H frame stand with a woofer - the OGY's Bass.
But the work continues and what was also evident during trials was that two bass drivers create even more presence. Don’t get me wrong, again it is not the boom effect that I’m looking for, rather more full bodied bass but still natural and fast.
The natural crossover point with the OGY seems to be optimal below 125 Hz as the OGY alone is able to go down to 40 Hz. What we obtain adding one pair of bass drivers to the OGY is bass enhancement by a few decibels in the sub 100Hz area. Adding another pair increases it even further.
So in a typical 20 sqm room, two pairs would be great. In a 50 sqm room 3 pairs would be even better.
In terms of sound pressure you can obtain a similar result with just one pair loaded by a well matched cabinet either transmission line or our distributed resonance cabinets like for the Vigo, sealed box, onken cabinet, front or back loaded horn or worst of them all a bass reflex. Each one gives different sound reproduction in the low frequencies and different speed. Some result in a very big cabinet.
At a certain point an alternative method is to add bass drivers in order to increase the cone area and move more the air in the room. However an open baffle will never reproduce the first octave, as it is physically impossible in a reasonable space.
In order to limit space, at least in terms of its width, I folded the front backwards which resulted in a box of the following dimensions: 35 cm height and depth and 40 cm wide.
This is BOB - Bass Open Baffle - bass enhancement module. The driver like in the OGYs Bass is fixed by one M10 screw from behind and only touches the front separated by a foam washer.
Now, if you want only one pair for the OGY, then the OGY's Bass is the best solution also because it is H frame and performs better than one pair of BOBs.
Yes I considered H frame for BOB too, but as a result of a compromise in terms of aesthetics the presented solution prevailed.
This way we are approaching a solution with two BOBs and OGY on top of them, which places the treble at the optimal height.
This set up can be driven by a 300B amplifier but at its limits. You can feel that more power would make it even happier by better controlling the woofers.
Finally for bigger rooms 3 pairs of BOB are even better, but here definitely you need a more powerful amplifier than 7 Watts. OGY is connected straight to the amp and there are no crossover components. The bass unit is limited in frequency by inductance coil only which is separated.
Connection: There is a binding post unit with a 10 mH inductance coil inside, connected by 1,6mm wire, with a ferrite core to minimize its resistance. This unit is not fixed to the speaker so should BOB be a part of a different system, then another type of crossover point can be chosen. to connect to the amplifier either a double set of cables can be used or a jumper between OGY and the first pair of BOB. Another pair of BOB is again connected with a jumper.
Now you can look at it not as on the monitor loudspeaker but as a full scale loudspeaker system.
All the qualities of point source full range monitors are preserved. You get a very coherent sound across all the spectrum, excellent soundstage, details and liveliness in sound and you have the bass cushion that fills the room with the musical foundations. As one of our customers pointed out, you can never have enough woofers!
The elinsAudio Mille amplifier is a top notch and top of the elinsAudio range of amplifiers. Two mono-blocks with Bang&Olufsen ICE Power Class D units and a dedicated long time fine tuned preamp. This beast - 1000 W per channel with 4 Ohms or 500 W per channel with 8 Ohms was developed to drive the most difficult loudspeakers effortlessly, as for example the Magnepans 3.7 you see on the pictures. The damping factor is astronomical here.
Why such a power house to drive the 15 Watt OGY?
elinsAudio is a small audio manufacturer from the city where I live run by two friends of mine Irek the Magnepan lover and Janusz the engineer. We have been friends for years, and maybe they are also partly responsible for the creation of Closer Acoustics. Throughout the years we have tried several of Closer Acoustics high efficiency speakers with their amps, but to my and their great surprise only when I brought just for fun the OGYs prototype to hook up with the Mille what we heard was jaw dropping experience.
That day Janusz and Irek said that the level of detail and the quality of sound was almost like that delivered by the Maggies. I knew I had something special :) By the way I heard the same statement from my very first customer who bought the first pair of OGYs and who used to have Magnepans 3.5 earlier.
The main point is: OGY is a very versatile loudspeaker and can be a centerpiece of a bigger system. As such it is not just a bookshelf loudspeaker.
It depends of the system and the room what part of the OGY universe would be applied:
- OGY alone on a real bookshelf
- OGY alone on the dedicated stand
- OGY with OGYs Bass
- OGY with one pair of BOB with a potential for a further upgrade
- OGY with two pairs of BOBs
- OGY with three pairs of BOBs
Check it out for yourself at Warsaw Audio Video Show, October 27-29, Hotel Radisson Sobieski, this system will be presented in room 718.
BOB
Impedance - 8 Ohm
Efficiency 94 dB
Power Handling 100 W
Dimensions
Width - 40 cm
Height - 35 cm
Depth - 35 cm