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Music & Interesting Media

Last Post by Anonymous 12 years ago

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sideband

(@sideband)

Posts: 4246

Famed Member Moderator

AFAIK there are some car radio sets that monitor road/wind/engine noise and automatically adjust the Radio. But I've not personally seen/heard one.

Yes indeed! Need I say it but Philips had these ages ago. I played around with one in the car for some time and it worked well enough I suppose. There was a transducer like an electret microphone that monitored the external noise and adjusted the volume (you could set the preferred level). Primarily to alter the volume with respect to road noise but they may have become more refined later. Like most things, Philips dropped out of the car radio market about 15 years ago so I don't know if the technology died with it.

Rich.

Posted : 08/03/2012 4:08 pm

Jamie

(@jskinner97)

Posts: 1755

Prominent Member Registered

Topic starter

Right, I have given up with Absolute 80s. It used to sound decent on 128K ASX.. Now it sounds like sandpaper.. Very scratchy and horrible and it is driving me mad!! I'm off to play some vinyl..

They also ruined it by using RadioPlayer!!

Posted : 08/03/2012 5:33 pm

Anonymous

(@anonymous)

Posts: 16851

Group Deactivated Account

A car based system needs really to vary the compression (according to noise level in car AND the program material) and the volume (according to noise level).

The noise level is best estimated by measuring:
Speed (term due to wind noise)
RPM (term due to engine noise, though exhaust noise level varies with engine load as well as RPM)
Axle vibration 10Hz to 100Hz (good guide to road/tyre noise due to type of surface).

The electronics to do the actual volume & compression is available cheaply since mid 1970s. No DSP is needed. The cheap CPU (< $1) used for Car radio User Interface and tuning control is well able to monitor 3 cheap sensors. Apart from Axle vibration the info may be on the diagnostic bus in most cars now.

Then you need to persuade the Stations that they are damaging listening figures because they are transmitting worse quality than people got in 1934. CAMRA = Campaign for Real Audio

Posted : 08/03/2012 6:46 pm

Anonymous

(@anonymous)

Posts: 16851

Group Deactivated Account

This is a subject close to my heart. I think FM stations such as BBC R2 and R4 the compresion levels have been reduced to a more acceptable level, but its still very high on some of the commercial stations. But the worst is our BBC R Bristol both on AM and FM. The distortion at high volume levels is often painful. I think Absolute's sound processor at the Washford 1215Khz transmitter is faulty. When they play a a record with a quite section you can hardly hear it so you turn the volume up, when the volume of the record or track increases you get blasted out. Its weird I have never heard anything like it before.

Posted : 19/05/2012 10:12 pm

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