audio settings in a car

[VJ]

Hello,

I recently purchased a new car navigation stereo, and was struggling with the sound settings. There simply are so many things to adjust (type of car, type/size of speakers, distance to each of the speakers, highpass frequency and slope for each speaker, lowpass frequency and slope, delays, SRS WOW effects - different types and strenghts, equalizer, ...). I adjusted the settings that are straight forward, will need to fine tune some things, but it made me wonder:
Is there no (free) software that analyses audio using a microphone? If that software uses a couple of "reference" audio signals (e.g. mp3s one could play back), it could analyse the sound and help to tell which frequencies are too quiet, and thus how one should adjust the equalizer...

Any suggestions?


Jörg

[az]

Any suggestions?

Fiddle around with it until you like the sound. You are the benchmark. And a car is such a dynamically noisy environment that you'll nebver get "Hi-Fi" anyway.

[VJ]

Yeah, I know...

My previous system had a list of equalizer settings for different cars (on paper), which was an easier starting point. It had far less settings, so far less things to mess up. With this new system I'm now working out the highpass filter frequency and slope for my front speakers....


Jörg

[az]

This sort of info might be in the datasheet or on the back sticker of your speakers. If they're factory-installed, you might try asking in a VW forum?

[xortam]

... And a car is such a dynamically noisy environment that you'll nebver get "Hi-Fi" anyway.

What!!! But I have a "Hi-Fi" switch on my car stereo, doesn't that mean I'm getting Hi-Fi!?

The feature I like the best on my car stereo is auto-leveling so it lowers the volume automatically as I come off the freeway with the sun-roof open. Nice!

[VJ]

This sort of info might be in the datasheet or on the back sticker of your speakers. If they're factory-installed, you might try asking in a VW forum?

Yes, I'll ask there...
(I don't really understand how this setting could work)

The feature I like the best on my car stereo is auto-leveling so it lowers the volume automatically as I come off the freeway with the sun-roof open. Nice!

Yes, it doesn't have that . My previous entry-level Blaupunkt navigation had speed dependant volume change, this top model Kenwood lacks such a feature .


Jörg

[az]

A speaker chassis is only made to reproduce frequencies in a narrow band. A broadband or fullrange chassis from about 30 Hz to 20 kHz (actual numbers will of course vary). In a three-way speaker system the bass chassis might reproduce frequencies from, say, 30 to 150 Hz, a midrange chassis 150 to 3000, a tweeter from there on upwards.

If you feed a chassis with frequencies it can't reproduce, you'll get distorted sound and may hurt your speaker, so, in ordinary Hi-Fi speakers, you have a crossover, a frequency-dividing network, that feeds each chassis the frequencies it's supposed to handle. This is probably the frequency setting you were talking about. But crossovers don't just cut off sharply at that frequency - they don't route 150 Hz to the bass chassis and 151 Hz to the midrange Chassis at full power. They slowly fade over, so to say. How steep this fade is is determined by the slope setting.

Ignore the green line of this chart, and it shows a typical two-way speaker system:

[VJ]

Yes, I know... My hifi speakers (Quadral Argent 70) have 2 connections. If you single wire it, you use the internal crossover; if you biwire it, you bypass the internal crossover.

However, the speakers in the car are connected via a single cable-pair (e.g. front left has its positive and negative wire). There are no seperate connections on the amp for tweeter and woofer.
This is the installation manual: http://images.kenwood.eu/files/prod/...al_man(EN).pdf
So I'm puzzled as to how the crossover setting can do its thing?

Jörg

[az]

I can't find any frequency or slope settings in there.

[VJ]

This is the user manual:

http://images.kenwood.eu/files/prod/888/5/DNX_DDX8022BT(GE).pdf

(I couldn't find an English manual)
It is in the Audio Setup (p. 66).

Apparently, the crossover and slope are set if you set the speaker type and size, so there may be no need for me to fiddle around with it.

But I just don't see how it could work if tweeter and woofer are not connected seperately.

[az]

As I see it, it's only used for the subwoofer output, which makes sense. You'll find the same setting in your home theater rig, if you have one. It just determines below what frequencies to use the subwoofer. If you don't have a sub connected, you don't need to concern yourself with it (though you should probably tell your stereo about the missing sub - page 64 in the manual you linked to).

[VJ]

Ooh, I get it!!!
It only determines which frequencies are sent to the speaker, regardless of whether it has a tweeter or not.
(I thought it differentiated between the tweeter and woofer of a single speaker, but it differentiates between entire speaker and subwoofer)

For the subwoofer, it is a lowpass filter, for all other speakers a highpass. But it will be set automatically in my case (system knows there is no subwoofer, and knows the speaker types and sizes that are present.

Thanks!


Jörg

[az]

In this case, as the crossover is built into the stereo, yes. This is normal for 5.1 configurations. Each of the 5 ordinary speakers probably has another crossover built into it, but gets fed only frequencies >100 Hz or so (and then distributes these among its chassis).

[VJ]

I got in confused with my hifi setup (woofer/tweeter crossover)...
It makes a lot more sense now...

Do you happen to know what they mean with the DTA setting (p. 65) ? The manual states that "it virtually positions the speakers on that distance". How does this impact sound?
(The unit in cm confuses me, esp. given the low default value of 15 cm)


Jörg

[az]

Distance Loudspeaker -> your ear

A higher value means the other speakers get their signals later, so the sound from all speakers reaches you at the same time.

All this stuff really isn't necessary in a car environment, just like 5.1 isn't necessary there.