Digital Audio Processing in a Carputer/Car PC for Dummies

[DerAlte]

Originally Posted by Sprucegoose

... while the atom is sufficient for doing everything required, it doesn't have the juice to do it fast enough. ...

Huh? Are you saying that while it can play video well, it cannot do fast forward or reverse fast enough? Hmmm... figures.

Originally Posted by frankmehta

For anything other than web browsing (without flash) and word processing. Atom is NOT recommended. Absolutely not. ...

Prejudiced, aren't we? Not recommended? By who? That's the wrong line of thought.

As I have experienced, it does everything just fine (not by @Sprucegoose's logic though ). It is the Windoze boot time that bugs, what with all the drivers and services loading at startup. I have used 4 different OSs on my board, and the other 3 boot in about 6 secs, compared to the 30+ secs Windoze takes. WinCE would be better. Since the CarPC is not my primary ICE, I ignore the booting time. Definitely SSD does help, but I am not going to spend another 6K on an Intel 40GB just to make Windoze load faster, no sir!

The only things my HU cannot do that the Carputer can are
1. Connect to Internet for streaming radio
2. Allow me to do telecons and videocons (I just have to stop where the broadband signal is strong enough to do it reliably, though)

[frankmehta]

As I have experienced, it does everything just fine (not by @Sprucegoose's logic though ). It is the Windoze boot time that bugs, what with all the drivers and services loading at startup. I have used 4 different OSs on my board, and the other 3 boot in about 6 secs, compared to the 30+ secs Windoze takes. WinCE would be better. Since the CarPC is not my primary ICE, I ignore the booting time. Definitely SSD does help, but I am not going to spend another 6K on an Intel 40GB just to make Windoze load faster, no sir!

The only things my HU cannot do that the Carputer can are
1. Connect to Internet for streaming radio
2. Allow me to do telecons and videocons (I just have to stop where the broadband signal is strong enough to do it reliably, though)

We must have noticed, over the last few days that people are very keen to know about the 'restart' and 'wake up from hibernate' factor. Most questions here are about that. Here's the thing. I have had this PC for about a year now. And I am in regular touch with an Asus Atom Netbook (my fiancee has one).
Trust me, the Netbook JUST can't keep up with most of the tasks I try with it.
Forget video, the damn thing takes more than a minute to come back from hibernation. I have given up working on that damn thing now, since my mobile feels snappier. It's a prejudice, no doubt. But justified by the fact that this i3 PC feels just fabulously quick and stays cool too. Coming back from hibernation and restarting quick is high priority in a carputer. i3 does it, ATOM struggles at it.

Just a few things your audiophile head unit will not do:'
1. 4 way active. Make that 5 way. Yes, you can do 5 way active with your carputer.
2. You can set a crossover to an odd value of 85 hz (an example) for times where cutoff 80 hz feels too low and 90 hz feels too high.
3. Not to forget that you can apply ANY CROSSOVER plugin, of ANY ORDER, be it Linkwitz Riley or Butterworth or whatever bakes your cake.
4. You wan't your system to sound like a Tube Amplifier. Ok, go buy one. OR else, just put the plugin in on your Audiomulch/Console, and VOILA, your system has the warm colouration of a tube amplifier. You can set values for 100's of tubes. You can make it sound like anything!
5. Phase Adjustment. You can do it for any speaker at any time. Not just the subwoofer, like in a normal head unit.
6. Channel Trim and 32/48/160 band eq. You Can trim all your channels the way you want (yes, some headunits have it. My eclipse did) and you can have xxxxxx no. of EQ bands. You can RTA at will and go tweaking and tweaking till you have your perfect sound.
7. Don't like the way it sounds??? New soundcard??? How difficult is it?? You can have a fabulous sounding system in minutes with the soundcard of your choice.
8. With the press of a few buttons, your PC turns from a docile, technically correct sounding stereo into a ROARING 5.1 output MONSTER with direct digital processing (without the need for a DSP or a channel processor)
9. iPod. iPhone. This is a MAJOR headache. Your newest iPod/iPhone becomes redundant when your expensive headunit is a year old and the newest iOS/firmware is launched, and your iPod/iPhone is just not detected. The Carputer will detect ANY damn firmware. Just load the latest iTunes onto it.


Guys, I can go on an on extolling the virtues of the car PC, but sadly we all gotta go to work (sleep)

Let's just leave the head-unit vs CAR Pc debate for a better thread. This one is just a technical rider on how to go about getting good sound. Let's keep it that way. I request mods to discourage any comparisons of any kind to any other audio source in this thread. It is most definitely going to be drawn into the equation at every point, but hey, we are here to get the best possible sound out of our PCs, and that's all we should do in this thread.

[Sprucegoose]

+ 1 to that...
@ DerAlte: it's not about speeding up the audio & video.. its just that an i3 will load the OS and the other required software MUCH faster than an Atom...
and since not only SQ is required but ease of use & convenience as well...

There's no point getting a system which takes 3 - 5 minutes to load...
Spend a bit more and get a faster system that'll load in under a minute...

When i finally decide to get myself a carputer, all system files will be loaded onto an SSD. Data will be stored across several other flash based storage media...

And i won't skimp on the Procc or RAM as well...
might just use onboard audio though

[jinu_joseph]

Hey Frank, is the monitor detachable or have you permanently fixed it. Do you get detachable monitor setups for Carputers? How much did the monitor cost ?

[frankmehta]

Originally Posted by jinu_joseph

Hey Frank, is the monitor detachable or have you permanently fixed it. Do you get detachable monitor setups for Carputers? How much did the monitor cost ?

Hi jinu. Even though the screen is mounted in my car professionally, you can mount this and remove it and take it back if installed in a different manner (hardware included in box)
The screen is an hdmi led one and cost about 10 k

[jinu_joseph]

Originally Posted by frankmehta

Coming back to the connections part, my soundcard has 4 primary outputs, front out, which provides output for the front tweeter amplifier. rear out, which provides output for the front midbass amplifier. side/surround out, which provides output for the rear fill amplifier, and subwoofer out which provides output for the subwoofer amplifier

Not clear on this. How are you amping your tweeters and Midbass spearately ? From your signature i gather that you have 4 amps - 2 DLS' (2 channel each) 1 JBL (4 Channel) and 1 Clarion. The clarion i guess powers the Sub and is connected to the Ceter/Subwoofer output of the Sound card. How are the other amps connected and to what outputs of the sound card.

Thanks.

[frankmehta]

Here's the thing:
Tweeters: DLS A2 ---- Output 1 on Soundcard
Midbasses: DLS A3 ---- Output 2 on Soundcard
Rears: JBL GT5-S644 ---- Output 3 on Soundcard
Subwoofer/s: Clarion DPX11551 ---- Output 4/Sub/Center on Soundcard

[jinu_joseph]

Frank some more questions.. sorry to be picking your brain.. but i am currently in the process of upgrading my ICE and suddenly the CARPC is looking very tempting. Before i go to Ajay with my revised plan, jsut wanted to be sure myself.

So I remmeber reading that you switched to from a m4atx to a OPus powersupply because of the incompatibilty with the Xonar D2X. What is the rating of the power supply you are currently using and did you source the OPUS from USA or did you get it locally, if so how much?

Also did you upgrade your battery to accomodate the increased power requirement of 4 Amps and the PC ?

[frankmehta]

Originally Posted by jinu_joseph

you switched to from a m4atx to a OPus powersupply because of the incompatibilty with the Xonar D2X. What is the rating of the power supply you are currently using and did you source the OPUS from USA or did you get it locally, if so how much

Hey there. The OPUS I have is the top of the line 320W power supply. Robust and very consistent. Cost me about 13 k with duties and direct shipping to India via UPS.

Originally Posted by jinu_joseph

Also did you upgrade your battery to accomodate the increased power requirement of 4 Amps and the PC ?

No. The battery and alternator both are stock. <knocks on wood>

[Digital Vampire]

Originally Posted by frankmehta

320W power supply

Isn't it a 360W model?
Opus used to have a 320W model a few years back but that was discontinued IIRC.

Did you get a chance to measure the power draw? 360W seems to be an overkill for your existing kit but surplus capacity is always good for future expansion and accessories. The 360W watt model was originally released for use with those good old power hungry P4 based systems.

@jinu_joseph
Instead of direct shipment from Opus, you could try the ICCworld or Shop n Ship route and I guess it could be a few thousand cheaper.

Also you could look at the 240W version which should be enough. You could use an online power supply estimation tool to see what is your consumption at 100% TDP and leave a buffer of 30-50W to be on the safe side.

[jinu_joseph]

Originally Posted by frankmehta

...
No. The battery and alternator both are stock. <knocks on wood>
..

But isnt that draining your battery. The amps needs a total of (85W x 2 + 150W X 2 + 65W X 3 + 850W X 1) 1580W. Now assuming that you use at normal 30% of total Amp capacity you are still talking about 474 Watts. Add to that the approx 200W required by the computer. Taking it to 674W just for ICE. This would atleast require a battery that can provide 12-56V-A just for ICE. Then you would require additional power for the Cars electricals.

Is my calculation correct or am i missing something ?

Whats the rating of the fiesta battery?

[frankmehta]

Originally Posted by Digital Vampire

Isn't it a 360W model?
Opus used to have a 320W model a few years back but that was discontinued IIRC.

Did you get a chance to measure the power draw? 360W seems to be an overkill for your existing kit but surplus capacity is always good for future expansion and accessories. The 360W watt model was originally released for use with those good old power hungry P4 based systems.

@jinu_joseph
Instead of direct shipment from Opus, you could try the ICCworld or Shop n Ship route and I guess it could be a few thousand cheaper.

Also you could look at the 240W version which should be enough. You could use an online power supply estimation tool to see what is your consumption at 100% TDP and leave a buffer of 30-50W to be on the safe side.

yes, sorry, it's the 360. Opus 360.
I didn't want to get the lower wattage version because I believe in keeping a lot of headroom when it comes to power. It's a good thing, sometimes.
My TDP will be most definitely more than 250 W considering I am using an auxiliary sound card, a conventional (read: Power sapping!) hard drive, a lot of USB devices including 2-3 portable hard drives and even one dvd writer and of course, a decently power hungry HDMI screen.
Hence 240 would have been really just about. (though I know it would have been enough)

Originally Posted by jinu_joseph

But isnt that draining your battery. The amps needs a total of (85W x 2 + 150W X 2 + 65W X 3 + 850W X 1) 1580W. Now assuming that you use at normal 30% of total Amp capacity you are still talking about 474 Watts. Add to that the approx 200W required by the computer. Taking it to 674W just for ICE. This would atleast require a battery that can provide 12-56V-A just for ICE. Then you would require additional power for the Cars electricals.

Is my calculation correct or am i missing something ?

Whats the rating of the fiesta battery?

My battery is a SUPERman!! It's a Motorcraft 43ah 390A battery.
Nothing of this sort has happened to it, and the car doesn't even dim the headlights or cabin lights even when music is playing at a higher than normal volume.
yes, songs with HUUUUGE amounts of low bass do slightly flicker the headlights, but trust me the electrical system of the Fiesta is quite hardy and takes quite a good load.
As Ajay (Bass&Trouble) told me once, it's the components of an amplifier that also make a difference. I am running premier DLS amplification which uses high quality caps etc. hence the power draw is not very high, compared to the power they produce. The star here is the Clarion Class G/H amp that has a lot of sophistication in this department and is super efficient, yet produces not 850w but a WHOLE 1550W of RMS power!!!!

No hiccups yet. All ok. Knocks on wood.

[DerAlte]

@jinu_joseph, the equipment does not need that amount of power all the time. The power ratings are the maxima - beyond which the equipment is likely to croak! The actual power drawn is likely to vary between 20% (during silent passages) and 70% (for short durations - unless one is playing heavy metal) of the rated figures.

[jinu_joseph]

Originally Posted by frankmehta

..
My battery is a SUPERman!! It's a Motorcraft 43ah 390A battery.
...

850w but a WHOLE 1550W of RMS power!!!!

Originally Posted by DerAlte

@jinu_joseph, the equipment does not need that amount of power all the time. The power ratings are the maxima - beyond which the equipment is likely to croak! The actual power drawn is likely to vary between 20% (during silent passages) and 70% (for short durations - unless one is playing heavy metal) of the rated figures.

@DerAlte, I am assuming only 30% utililization of amp capacity on average.

@Frank .
Based on the calculation above and further considering that you are using a 2 Ohm Sub the Amp wattage increases to 1550W and the total wattage of AMPs alone is 2280W, So if we assume just 30% of this is being used that would mean 684W. Now add to that the 200W required by the computer (since this will more or less be a constant and will not fluctuate like an amp based on volume etc) that takes the total ICE wattage to 884W (at 30%). We are talking about a 73Amp draw on the battery.

The battery is rated only for 43ah and the Fiesta alternator (I am not sure) but i think its rating should be around 65-70V-A. This would mean that there is a very high chance of the battery draining out even if the car is running.

So i think you need a lot more powerful battery?

Folks, what say does this sound right or is something wrong with my calculation

[jatinpatel]

@jinu

that was precisely my Question.

@frank

do a thing arrange for a voltmeter, start your S turn on all the electricals of the car and AC and also your ICE turn up the volume to a level you always hear to.

Set the volatge meter so 0-24v reading and connect both the leads to the battery terminal and let the car be idling ad just check the voltage figures you wiill be shocked and suprised.
If charging voltage is below 12v then your battery is gettin drained as compared to gettin charge due to much electrical load.