Car audio and dynamic range [Archive] - Audio & Video Forums


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Norm Strong
06-26-2004, 09:32 PM
There have been quite a few comments about the need for compression when music is played in the car. Otherwise the driver has to ride gain all the time. I solved that problem some time ago when using tapes.

I copy the music onto a cassette using dbx noise reduction. I play it on the car player as is, but with a large dollop of bass boost. The results are just what the doctor ordered.

06-27-2004, 04:31 AM
dbx noise reduction is intended to improve dynamic range of tape recorders to reduce the unwelcome tape hiss by compressing the signal on recording. This is done by boosting the signal when it is at a low level. When properly played back, complimentary expansion restores the original dynamics of the signal. (Dolby works similarly but is frequency selective.) Without this expansion on playback, the signal remains compressed. This would be true for most all automobile tape players since switchable Dolby but not dbx is frequently offered. Therefore, if you have Dolby noise reduction, leave it turned off. This can be effective but it is not optimized for listening in a car the way digital compression of cds is. The problem of engine and wind noise in a car is usually worst for listening to classical music because much of it has a wide dynamic range. This is why concert halls for classical music are designed to be quiet and why coughing and rustling of papers in the audience can be so annoying. Pop music usually doesn't suffer from this problem because of its inherently limited dynamic range.

I have found that the single level of dynamic compression offered by the Sony cd player in my 8 year old Lincoln and the three levels of compression offered by my 12 year old Sony car discman are very effective and well designed for this purpose. As for bass boost, that's a matter of your personal preference and limitations of the sound system in your car. BTW, IMO, the performance of the Ford JBL system in my Lincoln stinks. (I bought the car used for other reasons and it just happened to come with it.)