Sonab V-1 was the first small cube-shaped Carlson-speaker. It was introduced in the late sixties as budget speaker. It has no crossover and uses only one speaker unit, the Philips 9710. This is a full range speaker used in Stig Carlssons other designs as a midbass or a midrange unit. As in the other designs the speaker is set in a factory adjusted acoustic damping device made of a mesh-basket and glass wool blanket. This gives a better response to transitions, a smoother frequency response and better bass-response.
The V-1 was sold as a cheap “pop-speaker” for the teenager room. It was available in colours to match this. I have one pair of V-1 myself and I think that the soundquality is below the usual Carlsson standard. The sound is close to an ordinary kitchen radio and the stereo-imaging is rather poor. There are some pros with this design such as there is no sound degrading from the crossovers. However the cons are more obvious, the bad frequency response and the bad bass-reproduction outweigh the pros by a big margin.
Still, a lot of people has had a pair of V-1 as their only speakers for decades and been quite happy with that. It is a Carlsson speaker…
The standard V-1 is a simple “one-way” speaker that leaves no lasting listening impressions.
The frequency response is poor and the stereo imaging is not very good.
It needs to be upgraded. An upgraded V-1 can be better although it will remain a bit thin in the bass response.
Most items, such as “full range speaker 9710”, “cabinets”, “internal wiring” and “terminals” are done according to Restoration and upgrading
However consider if you think it is worth the trouble for this speaker.
There are three areas in which the V-1 is inferior to other Carlsson designs:
Bass response, frequency range and stereo imaging.
There is not much to do with this aspect it is determined by the speaker unit and Box-size. This is however the least of the problems with this speaker and if it might be acceptable.
The frequency range is limited as the 9710 speaker that does not have a perfect response in the higher frequencies. On-axis the drop starts at 15kHz, off-axis it starts at 7kHz. This can be resolved by installing tweeters in the same way as on the “popboxen” Four inward facing tweeters circumference the 9710 with a crossover copied from “popboxen” or the “OA-5” gives a better frequency range.
Recommended tweeters are Peerless MT20HFC which is the standard part used by Sonab at that time. Better still is to use the Peerless CT62. This is a modern replacement for the MT20HFC. It is a modern tweeter with better data and is recommended by CarlssonPlanet.
If you opt for this solution use four pcs. of eight ohms units in series-parallel configuration. The crossover is 6/12dB at 2700 Hz with two air-cored inductors 0.5 mH and one capacitor 5 uF.
The mentioned solution can sort out the problem with frequency but not with the stereo imaging. In order to resolve this you need to have directional sound. The normally recommended way to achieve this is to set the tweeters in a Y configuration. However space on top of the baffle becomes a problem in this case.
Let us look at other Carlsson designs for a solution. Two models stand out as possible: OD-11 and OA-12. The OD-11 has one tweeter facing into the room at 45 degrees.
The OA-12 has two tweeters, one diffusing facing backwards over the midwoofer and one facing into the room at 30 degrees.
The OD-11 uses one pc of MT20HFC / CT62 in eight ohms and the OA-12 uses two in sixteen ohms. My personal preference is to use two sixteen ohms tweeters.
TECHNICAL DATA Sonab V-1
According to Sonab’s handbook and/or the Swedish ”Hifihandboken – 1973”
Box volume: 21 litres
Measures B x W x D: 31 x 30 x 30 cm
Weight: 10 Kg (?)
Principle: Omni directional, bass reflex type.
Placing: Floor standing against the wall or hanging upside down from the ceiling, placed against a wall.
Impedance: 8 Ohms
Frequency range: 49-17.000 Hz
Frequency response: 50-13.000 Hz ± 6dB
Crossover frequency: No crossover
Speaker units: Full range, 8 inch Philips 9710, 8 Ohms
Finishes: Rosewood, walnut, teak and white, red, yellow or blue lacquer.
Prices: 1973: 330 SEK per pair.
2nd hand: 50 up to 700 SEK per pair depending on the finish.
Upgraded: Maybe up to 1.200 SEK.
The value, if there is any, of this speaker does not come from its qualities as a sound reproducer. They are imprecise and the sound is not up to modern standards.
But never the less, it is still a Carlsson speaker and can be upgraded somewhat.