Hearing problem

[hansgitaar]

Hello everyone, hello Ted,

Due to a ripped eardrum (and subsequent operations) I have tinnitus and hearing loss in the left ear. I am a classical guitarist and love to listen to my stereo. A bit of a problem is posed by the enormous dynamic range in classical music. Could a compressor (in the right place in the audiochain) help me out? When an orchestra is playing pianissimo, my tinnitus is louder than the music. If I turn up the volume, the forte parts then get asocially loud. Could a compressor help?

Thank you for your efforts.

[Ted Fletcher]

Sorry to read about your hearing problem……
The short answer is yes; it is certain that using a compressor will make it possible to hear quieter sections of music. The principle is a good one, the real question is how to produce a compressor with the best characteristics so that it works well enough without destroying the musicality of the audio.
Over the years I have experimented with many types of compressor and have had systems that would probably do the trick, but I must think further on this…….. I’m going to consider it for a few days and will come back to you.

[Ted Fletcher]

As it happens I do have a number of compressors in stock so was able to do some experiments today……
At first I tried putting some classical music through the limiter circuits of my new 828 Mk3 mixer. This was not a success, the limiters do the job of preventing overloads perfectly, but when pushed, add a degree of harshness without accenting the quiet sections sufficiently.
I also tried my P38EX mastering compressor, but I think this one is generally too well behaved; it refuses to carry out the necessary increase on quiet passages.
Lastly I tried a combination of two TFPRO538 stereo compressors in a 500 series rack. Having thought about it overnight I wanted to try using a fast and sharp compressor to bring up quiet sections and to follow it with a much slower’heavy’ compressor to operate more as an automatic gain control for the complete signal.
Of course, the 538 is a sophisticated compressor in its own right; it already has shaped attack and release curves and reacts at different speeds depending on the level and dynamics of the signal, running two of them in series I expected a greater degree of control.
The system works extremely well. I have the first compressor set with about 18dB of audio gain, slowish attack and fast release, with a compression ratio of about 10:1.The second compressor has about 15dB gain, fast attack and slowest possible release. The ratio is about 6:1.
The result is an extremely complex array of time constants that hold the maximum volume level stable and brings up the volume of quiet sections by as much as 22dB with remarkably little noticeable level shifting. The result is acceptable quality and I think, offers a solution to the particular problem.
I’m not sure that this is a practical answer as these compressors are not cheap, but it is certainly an answer. Ideally, I would design a completely new compressor fitted with dual sidechains and optical circuits to emulate the effect of the pair of 538s, but I think the cost would actually be greater than for a pair of existing 538 compressors!
If you are interested in taking this further, please email me at [email protected]

[Ted Fletcher]

I have been thinking about it!
This problem keeps cropping up;I have had many requests for equipment to improve listening on TV.
Presently, and partly as a result of these requests, I’m working on the development of a new TV loudspeaker (working title TVTR) which will be a simple low price device, but fitted with a form of filtering and compression specifically to help with perception of dialogue. By definition this will help with listening to all types of sound where the dynamic range is too great or where there is interfering noise.
The new loudspeaker will be under the Orbitsound label and should appear mid next year.

[Hammy Havoc]

Very excited about the TVTR! Is it DSP-based, or an optical circuit?

[Ted Fletcher]

You guessed right! It’s very much an optical circuit. The dynamics of mixed music and speech on TV is highly complex and extremely difficult to apply control to. My circuitry combines some active filtering (which other audio manufacturers try) together with some compression. The result, happily, is that neither is very noticeable, but the dialogue is clearer! One would think that digital control would be easier and better, but there’s more to it than meets the eye (or ear).

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