What kinds of IC amplifiers would Kenwood use?

Automotive hifi gurus rate 10% thd as the limit these days, if you check out the spec sheets on auto ics

Compare music to drinks. Some is like a strong brandy. Some is like a fine wine. The music you're playing sounds like Diet Coke

sort of sums up the car audio industry

martin

Keep in mind that there is little point in having a 0.01% thd system when you've got 60db of road noise.

I wish audio compression was available on CD players so I could listen to classical music and hear the quiet passages without the loud ones exceeding

ISTR that there have been several schemes for including gain ranging stuff on CD's and RDS, but they couldn't afford to pull a competant audio dude from tossing burgers at Big Mac to do it

martin

Perhaps audio process the original CD with software and burn a new 'tweaked' CD. I'm pretty sure there's audio apps that can do that.

D from BC

Any AM radio station has a expander/compressor to keep the modulation stabilized... maybe something of that sort?

...Jim Thompson

It is all about the specmanship. The specmanship does matter.

On the 10kW car amp design, I provided the compressor so you can limit the power to mere 1 kWt :-)

During the long drives, I like the noise reduction headfones (mine don't go up to 300MHz like others but still good enough)

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

lol :) ....Unable to pull an audio topgun away from McDonalds.

"Would you like a compressor with your fries?"

"I compressed those patties myself."

D from BC

Audiograbber should be able to do normalization; also the apps mentioned here:

Michael

It depends. There used to be a guy out here tooling around in a heavily modified VW beach buggy with flames painted onto the sides. Had the stereo all cranked up. Tchk, tchk, BOOM, tchk, tchk, BOOM. He was at least 70!

Around here, only teenage drug dealers can afford silly stuff like that. :P

D from BC

But they won't drive a dune buggy. They glide around in gold-studded Cadillacs with mag wheels.

Yep, us ol' farts like disco ;-)

...Jim Thompson

snipped-for-privacy@gmail.com hath wroth:

(...)

Kenwood schematics can be bought and downloaded from various online vendors for reasonable prices. If you plan on tinkering with the radio, the full service manual might be a good investment.

This looks tolerable for $5.00.

AZ Nomad hath wroth:

Yep. Perception is everything.

My Kenweird car stereo has an "loudness" button which does the exact opposite. The expander is to counteract the effects of everything in the broadcast chain that's doing compression. Now, you want even more compression? Are you sure? If you bring up the quiet passages, or bring down the loud passages, that's still compression.

I looked at the specs for various car stereo "audio processors". Lots of frequency response control, but I couldn't find any with compressor or expander controls. Very strange.

One possibility is a car stereo that has an ambient noise detector, that adjusts the stereo volume accordingly. That won't do what you're asking, but might help.

Incidentally, the industry is thinking of you and your car stereo. There are no longer any quiet passages. Instead, most recordings, including classical, are heavily compressed, limited, and sometimes clipped. The idea is to raise the average loudness level. There are various reasons for doing this, but even with classical music, loud sells advertising better than quiet. The local classical music FM station seems to only play the loud movements of popular classical pieces. See:

for a good explanation of what's been happening. I've looked at the resultant mess on an audio spectrum analyzer and noticed the over compression. I've also noticed that an effort is being made to fill in the dead gaps with background noise, music, or even simulated road noise, all in order to increase the average sound level.

Incidentally, when I was playing engineer at my college FM radio station in the 1960's, I also had a 2 hr classical music show around midnight. Sometimes (usually during exam times), I would crank up the compression until the dynamic range was perhaps 10dB at best. After that, there were no quiet passages. It wasn't clipping, but it was close. The phone would sometimes ring with complaints that it was "too loud" or "over-modulated", but nobody ever complained that it was distorted or overly compressed. Yep, perception is everything.

Late at night, by candle light, D from BC penned this immortal opus:

I believe Audacity is able to do that.

- YD.

Jim Thompson snipped-for-privacy@My-Web-Site.com posted to sci.electronics.design:

Possibly, but could you make them cheap enough to install in a million units without raising the price more than US$5?

It;ll do it manually, but I haven't figured out how to do it automatically. Audacity is a great tool, but it does have its weirdness.

On a sunny day (Thu, 29 Nov 2007 22:24:18 -0500) it happened krw wrote in :

Hey keith, please keep to a subject you have a clue about.

Your 25 dB gain is likely part of the AGC option of that thing. I know this, I use this, not this one, my own. But I do not split in separate bands... interesting idea, have to think about that.

On a sunny day (Thu, 29 Nov 2007 16:38:00 -0700) it happened Jim Thompson wrote in :

That is called AGC dumbo, it even sais so.

same

BYE