white noise in car stereo

beat · « **on:** 28 Feb 2008, 03:12 am »

Hey guys,
didnt we used to have a 12v circle? Anyway, I'm new to the auto stuff. I got big fat amp, a coule of 10s and the sort of line array across my dash now. When playing cds, there is alot of background noise. I mean quite alot. I would blame it on other components but I'm building the car from scratch and this is the first thing I've hooked up. It is grounded. The interconnects are shielded as are the speaker cables (yeah, I know its a no no but...) I'm wondering if I'm just overlooking something obvious.

thanks, Beat

mcgsxr · « **Reply #1 on:** 28 Feb 2008, 04:00 am »

Does it vary with RPM? Could it be alternator whine?

Jim N. · « **Reply #2 on:** 28 Feb 2008, 04:03 am »

Check the gain on the amp. Set too high and you can get a lot of noise.

Folsom · « **Reply #3 on:** 28 Feb 2008, 06:22 am »

The power cable to the amplifier is a huge possibly culprit. You would be surprised how many loops and things run through the entire body/frames etc of a vehicle, and how much noise you can get.

Bob in St. Louis · « **Reply #4 on:** 28 Feb 2008, 11:52 am »

Do you hear it with the engine turned OFF?

beat · « **Reply #5 on:** 28 Feb 2008, 03:44 pm »

Hey thanks for all the replies guys,
The motor isnt wired at all..not even the injectors much less the alternator at this point. I started with a brand new harness and worked my way from the boot (trunk) where the amp is and got as far as the ingnition switch. So I dont even have anything in the dash really hooked up yet. So I think all that leaves me with is the power going to it, or the gain is too high. I bet thats it. I'll get out there today and fiddle with it. I'll let you know how it goes.

Cheers y'all.

Bob in St. Louis · « **Reply #6 on:** 28 Feb 2008, 04:06 pm »

I don't know man, that's a strange one. I've seen lots of noisy car audio systems, but essentially you don't have a "car" system yet. You've just got a 12v system since that's all that's wired up.
Well, at least you've got your priorities right doing the audio first.

Only an audiophile would wire the tunes before the ignition/fuel systems.

Bob

Hap · « **Reply #7 on:** 28 Feb 2008, 05:04 pm »

Other than properly setting the gain on the amps, make sure you have good ground connections with a clean path back to where the battery ground wire is located.
You can get a bastline by first lowering the pots on the amps all the way down, then turn your source volume control to about 90% max, adjust the amp gain up until the speakers start to distort.
Good luck.

beat · « **Reply #8 on:** 28 Feb 2008, 08:19 pm »

Well crap!

didn't realize my volume went past 40 something. Even with the level (as they call it) set to zero on the amp I couldnt turn it up past mid 40s as I would have woke the dead..then everyone would be hating me more and more as these zombies ate their loved ones, co-workers etc.. etc.. I just have them set at about 30 percent now and yeah, the noise is gone. Dont know why I didnt think of that.

Well it was a good excuse to hear from you guys.

Cheers, Beat

Bob in St. Louis · « **Reply #9 on:** 28 Feb 2008, 10:47 pm »

Ok, now that we're done with all that............
Let's see photos of the hot rod! aa

Bob

beat · « **Reply #10 on:** 29 Feb 2008, 05:19 pm »

Quote from: Bob in St. Louis on 28 Feb 2008, 10:47 pm

Ok, now that we're done with all that............
Let's see photos of the hot rod! aa

Bob

Thought you'd never ask! I was thinking once I get it all wired up and running I would seal the holes in the firewall and then add some acoustastuff to create more of a sealed box. Engine is a turboed 1.6 vtec, engine management by microtech. The funny thing is I kept the stock (well I had to modify it for the fuel pump) little mini gas tank. Its like 9 gallons.

Bob in St. Louis · « **Reply #11 on:** 1 Mar 2008, 12:36 pm »

Oh dude, that's going to be a BLAST!
Vintage Cooper vehicle with modern Honda powerplant. Yea baby!!
That dash is very sexy. The gauges are extremely classy and integrate very well with the tweeters in the wood. It that some species of figured Maple?
Do I see some special kinda calipers in there?
Is this a future SCCA entry?
Can I drive it?

Bob

beat · « **Reply #12 on:** 1 Mar 2008, 11:37 pm »

Quote from: Bob in St. Louis on 1 Mar 2008, 12:36 pm

Oh dude, that's going to be a BLAST!
Vintage Cooper vehicle with modern Honda powerplant. Yea baby!!
That dash is very sexy. The gauges are extremely classy and integrate very well with the tweeters in the wood. It that some species of figured Maple?
Do I see some special kinda calipers in there?
Is this a future SCCA entry?
Can I drive it?

Bob

Thanks for the props! Yeah it will be a steenkeeng blast! Probably scary even. The wood is Sapele (pronounce it with long E sounds) Imbuya. Sapele is the wood and Imbuya I think indicates that its a burl or some sub species maybe. Its tropical African. The calipers are just regular large Coopers I just ditched the drums and put these on after rebuilding em. Still pretty little at like 8.4 inches or around there but are the biggest Cooper ever used to my knowledge. This car was actually never a Cooper just a regular mini. I think it would be a shame if I never took it to the track huh? I might but it wasnt the intention. If you are ever out this way shoot me a message and hopefully I'll have it going.

adios, Beat

Rocket · « **Reply #13 on:** 2 Mar 2008, 12:24 am »

Hi Beat,

It looks very complicated rebuilding the vehicle are you a mechanic by trade?

Regards

Rod

beat · « **Reply #14 on:** 2 Mar 2008, 06:28 pm »

Hi Rod,
No. I'm not..I just pretend to be. This thing has been a serious challenge for me.

Se7en · « **Reply #15 on:** 2 Mar 2008, 10:01 pm »

That thing looks like it is going to be a blast when it's done! I really like your dash work as well.

I used to be pretty heavy into the 12v thing and can make a few suggestions if you continue to have noise problems. Primarily, make sure you have common ground for all of your electronics. Using multiple grounds creates all sorts of loops in the system. Probably the easiest location is the seatbelt bolts as they go straight to the frame of the car.

Although it looks like you're pretty committed to your dash configuration, if you find that you're not entirely happy with the sound, you should consider you kick panels for your mids and highs. This will give you closer to equal path lengths and in most cases will also provide a nice high stage right in the center of the car. You may need to play with your phase to better time alignment for left right, also digital processing for the car is cheap these days.

Here's a couple of pics of my last car...

5 mono'd butlers tube drivers where the rear seat used to be

All covered up

More pics if you're interested www.lagmonster.info/transam

beat · « **Reply #16 on:** 3 Mar 2008, 02:53 am »

Holy Cow that thing is sick! Butler amps? Where did you find those? I was actually thinking last night that I might want to add some speakers in the side somewhere. The Doors on these mk1 minis arent enclosed so I would have to build a box of some sort.. I think I will but the drivers will have to be quite little. No problem though as these hivis are made as small as 1". Thanks for sharing your TA.

Folsom · « **Reply #17 on:** 3 Mar 2008, 03:20 am »

The Butler tube amplifiers are actually hybrids. They do sound nice, they are very nice. The problem is they are only ideal for tweeter and mid-range. They are a little soft in the mid-bass and subwoofer, so people into SQ car audio find other amplifiers to deal with this area usually.

Se7en · « **Reply #18 on:** 3 Mar 2008, 04:18 pm »

I would agree that typically butlers are not the ideal sub amp, but this car was not lacking in the lower notes by any stretch.

Each of the Hex/Eton 8" mid bass drivers in the doors was seeing it's own bridged butler (approximately 400w per side). The amps were obviously gained way down but offered incredible driver control. The doors were low passed at about 50hz where the subs then took over. The cigaratte lighter was converted to a sub controller and generally speaker you never knew (from listening anyway) that there was a sub in the back at all. This car had a wickedly dynamic front stage. Sheffield Labs drum tracks sounded and felt like there was a truck coming through windshield.

The only problems that I had with the Butlers was: 1) they got VERY hot inside that car, to the point of being pretty uncomfortable. 2) They were not particularly efficient and were not the final word in "headroom". At full tilt I was pulling about 230 amps from the batteries. 3) They were fairly big and depending on your application, at approx 17 pounds each, the weight of 5 of them adds up pretty quickly. All told and extra 500lbs was added to the weight of the car. That's like have 3 averaged size people in the car with you at all times. Not particularly fun to drive.

You live and learn. If I were to do it again, I think I would take a decidedly different approach. For a car like the Mini, I'd seriously look at the Alpine PDX Ice powered class D amps. Although not the final word for SQ, they're tiny, sound great and really pack a punch for their size.

-7

DaveC113 · « **Reply #19 on:** 3 Mar 2008, 06:05 pm »

I had a ppi tubedriver, nice amp... although I agree w/7, class D effeciency in a car makes a lot more sense.... I've already recommended the Alpine class D amps to others, thats what I'd use next time too. I did use an Alpine digital sub amp with the tubedriver, its nice to run a small 8 ga wire for a sub amp.

The Alpine V12 5 channel amp is great for systems that don't want to get too big or expensive, in most cases it'll work with the stock electrical system...

Dave