The Clean Sweep 20Hz-200Hz 7 day hire

The 'Sitting Room chorus' is a major cause of poor Hi-Fi and Home Cinema Sound. It occurs when low frequencies from your speakers 'excite' loose furniture and fittings in your room. Furniture such as cupboards, radiators, gas or electric fires, tables and chairs, and ornaments - glassware, china, pictures, lights and light fittings - rattle in time with the music, but the rattles sound like they are the music, adding a harshness to the sound. Curing them is simple – it’s simply a case of wedging rattling doors and windows, using blu-tak to stop ornaments vibrating on shelves. It’s the finding of the rattles that’s the difficult bit - precisely where Russ's new Clean Sweep comes in.

Clean Sweep is a signal generator that connects to your Hi-Fi amplifier's analogue inputs and produces tones from 20Hz to 200Hz. Its key feature is that the different tones are operated manually by the user, so that if you find one particular frequency that sets off rattles throughout your room, you can hold it there while you cure the problems. It’s fascinating using one and finding out how much noise your room is adding to the music… and, once you’ve cured them how much better your music sounds!

Clean sweep is mains powered and connects to amplifiers with phono (RCA) inputs.

Clean Sweep can also be used with new speakers to burn them in, giving your speakers a real ‘work out’. It loosens the initial stiffness of new drivers, helping them sound more dynamic and with deeper bass.

Russ on the sitting room chorus...

"Way back in the early 1970s, when I was a Hi-Fi dealer in Edinburgh, I had a salutary experience one day when installing a new Hi-Fi system in a customer’s house. As usual, I had set up and tested the system in the shop dem room so I knew it was working perfectly - but installed in the customer’s house it sounded terrible. Not just bad - faulty! I couldn’t believe it.

"Had the stylus dropped out? No. Was the cantilever bent? No. Mystified, I put on the HFS 69 test record I always carried and found that the system sounded fine at a very low level but as the volume increased the gross distortion effect appeared. As it was just a single frequency tone signal, I was able to hear some very nasty noises coming from various parts of the room.

"I found that the nasty noises were coming mostly from a gas fire and a china cabinet. We silenced the gas fire with a thick blanket (it was unlit and cold!) and then went to work on the china cabinet. Not only were the glass panels in the cabinet rattling, but the cups and saucers were rattling too! We fixed all the rattles and the sound from the system was fine. An important lesson learned. I’d discovered the ‘sitting room chorus’.

"A few tests in other rooms proved that this was not an isolated, one-off problem. It was just more severe than most. Using a signal generator, I found that most rattles are caused by bass frequencies below about 200Hz. Starting at 10 Hz at a moderate to high listening level, I slowly increased the frequency and found a different rattle at almost every 1Hz step"! Clean Sweep

Use the Russ Andrews Clean Sweep test tone generator to listen for rattles as the tone sweeps up from 20Hz to 200Hz.