Some Audio Questions

[SteveXs2]

Sorry to dump these here but I had to return the book on car audio I got from the library and google is useless in trying to find these answers since I just get places trying to sell amps.


1) Can wattage be restricted? My amp is 50W RMS/ch while my speakers handle 40W RMS. We used resistors all the time in Physics class, are there resistors made for this purpose? My tweeters are protected by the crossover but I don't want to harm my mids by giving them too much power and the deck is useless in powering them (like 11W RMS?)

2) Can two channels be bridged on a 4 channel amp? This is probably subjective to the amp, but ideally I'd like to have two channels for my components and then two channels bridged for my sub. If not, I'll just end up buying another amp which isn't really ideal.

Thanks in advance.

[Mr_Diesel]

The rated RMS of a speaker and amp is at peak levels.... For instance, at very low volume levels, very little power is being used. Just because your speakers handle 40W where the amp puts out 50W doesnt mean it will harm them.... You just need to limit the volume level on the deck, or turn down the "Gain" knob on the amp.

On most amps you can bridge the channels. It varies from amp to amp, but I had a 4 channel sony amp that you could bridge into a 1 ohm 1 chanel output. You need to read up on your specific amp, but I can tell you that most modern 2 and 4 channel amps can be bridged.

Remember, when you bridge 2 channels, you reduce the ohms from 4 to 2.... This will effectively double the output of the amp on those channels.... If you have a 1 channel amp and your subwoofers in a series circuit, you take the ohmage down to 1 ohm.... a 200W rms amp could put out 600-700W peak at 1 ohm... Pretty cool stuff.

You WILL fry your little resistors if you try to put those in line.... No need for all that crap, just turn down the gain knob and your speakers will be fine.

Remember, you can usually tell when you are overdriving a speaker... It will start to distort and what not... You could have a 15,000W amp running a 1W speaker, and it wouldnt hurt the speaker as long as the gain was turned all the way down, or you kept the volume level low.

I have installed dozens of systems in my own cars and friends cars... My theories and opinions might not be 100% accurate, I am just telling you what I know, and the experience I have had... Feel free to ask any other questions... chances are if it's car audio or diesel, then I have done it.

[SteveXs2]

Awesome, thanks man.

I've got the gain set to about 1/2 right now but I haven't formally tested the speakers because I've only got one in and my boxes aren't quite finished yet.

I'm heading down town pretty soon though to go check out some more amps. Ideally I'd like to have a 4 channel amp powering my components and two 8" subs but that's more money than I'd like to spend right now. I may, however, be able to borrow some subs from a friend. After all, they've just been sitting in his shed for about a year because they're not really his.

[Mr_Diesel]

Awesome, thanks man.

I've got the gain set to about 1/2 right now but I haven't formally tested the speakers because I've only got one in and my boxes aren't quite finished yet.

I'm heading down town pretty soon though to go check out some more amps. Ideally I'd like to have a 4 channel amp powering my components and two 8" subs but that's more money than I'd like to spend right now. I may, however, be able to borrow some subs from a friend. After all, they've just been sitting in his shed for about a year because they're not really his.

Get a 1 channel amp to power the subwoofers, and run the tweeters and mids off the deck... It will sound better.

[MKIIVR6]

On my system I have the subs running off of a two channel MTX 2160, the front's (3.5 in the dash and 5.25 components in the front door cards) running on two ohms, on an MTX 280. Another MTX 280 runs the rear 4x10's in the rear door cards and 6x9's in the rear deck, also two ohms. The amps are controlled by a powered crossover (gain and manual crossover control), which makes the whole thing quite controllable.

The only thing I would check for sure if you do bridge your amp is to make sure it can handle the impedence you are bridging it to. Back in the days of selling car audio once in a while a customer would buy the gear and install it themselves, bridge it down to 1 ohm when the amp was designed for a minimum of 2 ohms. Cooked amp.

On my system I run the subs via 4 ohms, as the sound output is enough for my tastes. Each channel is running it's own sub, and the box is baffled (seperated for each sub) Tempted to install some JBL gti 12's, and run a 3" duct for each sub chamber through the rear deck down into the sub box just below. I have a feeling it may be overkill doing that though. :)

[SteveXs2]

K, the amp problem is solved. Just as I was leaving the local shop, Sight & Sound, a friend of mine who's really into SPL shows up and I talk to him for a bit outside. He was about to sell his 145db '96 Tacoma when some lady offered him the same amount he paid for it 50,000km ago, but decided to keep it and is putting his two kicker 10" subs in there (the square ones).

So, he's getting a new deck, too, and I'm buying his old one. It's one of the alpines that puts out 45W RMS per channel and lets you adjust your speakers for where you're listening and all that. I'm stoked, but he said he was going to call me 3 hours ago when he was putting everything together but he either forgot or I gave him my cell phone number wrong.

Anyway, it's a $400 deck but I'm getting it for far less than that :) In fact, it was less than the cheapest deck the place sells.

This guy is also involved with a group that does custom audio stuff around here. Fibreglass enclosures, tuned boxes, custom center consoles, all that stuff, and I guess one of the guys in the group who used to work at Sight & Sound is going to have a 4 10" sub setup. Considering that he was around 147db with 2 10" type-Rs, they estimate he'll be at around 160db with the 4 10s he's looking at. Should be nuts.

[SteveXs2]

Damnit! No more head unit for me. The guy decided it wasn't worth selling since he was going to sell it to me for $120 Canadian.

Ah well, guess I'd better go and shop around for another one up town. They had a decent-range Alpine one there on clearance for like $170 or so. Man I got my hopes up... I've been sitting here doodling on CDs I'll soon burn full of mp3s.

[MKIIVR6]

I have access to wholesale costs on most home/car audio equipment. For example, a $300 head unit costs me about $160 + taxes. I just have to make sure the rep I know at the distributing company is still working there. If he isn't, I simply pay around $50.00 a year for a buisness license. Kind of like a Costco membership. :lol: The margin for retail audio equipment is probably around 30-40%. 8O

[SteveXs2]

Actually, I just found out something that may help my problem after all.

I only ran my Type-Rs off of my deck for a first-try type thing and they sounded pretty bad. I disconnected them promptly and connected them to my amp instead. I thought my deck was only putting out 11w RMS because I overheard a very knowledgeable guy say that most decks do only put out around 12W while alpine tops the charts with 16W, and I guess this found its way into my head.

After a little research, I found that from the different sites, my kenwood deck supposedly is rated at 22W RMS. Sounds much better than the 11W RMS I suspected.

So... I'm going to try this out and see how everything sounds. I won't do any little tests at all. I'll get EVERYTHING done and wired up properly and then blindly configure the EQ, gain, speaker settings, etc. and then try it out to see how this thing sounds. I think that doing it that way will be the only way to really know whether or not I'll need another amp for the components.

If this works out, I can start to concentrate on other, more important things like MY TRUNK.

Anyway, I'm off to bed. I've got to pick up a TV in the morning and then I've got 10 hours to work on my car. The only bummer is that a friend of the family is using our shop since their table saw died so I can't finish my boxes. I'll have to work on installing the rear speakers and wiring and stuff instead depending on how long she takes.

[TisforTurbo]

I have access to wholesale costs on most home/car audio equipment. For example, a $300 head unit costs me about $160 + taxes. I just have to make sure the rep I know at the distributing company is still working there. If he isn't, I simply pay around $50.00 a year for a buisness license. Kind of like a Costco membership. :lol: The margin for retail audio equipment is probably around 30-40%. 8O

really? i was thinking about getting just a sub/amp combo for the ol gli...

[MKIIVR6]

I need to contact the buyer I used to work with back when I sold electronics/appliances and see if he still works at the distrubutor. Lots of pioneer, mtx, jbl, ... and on and on.

Been wanting to connect my mp3 player to the car, and rather than resort to the fm modulator method I've found that there is a ip-bus-rca adapter to run inline with/without a cd changer.

Here is one that will allow a p-based changer to run inline:

http://i12.ebayimg.com/01/i/03/de/fe/ba_1_b.JPG

Here is one for use without a changer:

http://i7.ebayimg.com/01/i/05/b8/23/2b_1_b.JPG

I ordered the bottom one for the work truck (yes, I installed a deck in it) :lol: And judging by it's performance, I'll buy the top one for the Jetta. The Jetta already has a pioneer changer in it, and this would really add to the functionality of it all. I could listen from the main mp3 player I have, a Gateway DMP-X20, or my Compaq Ipaq pocket pc, or my Casion MP3 wristwatch. 8)

[SteveXs2]

Nice, sportin some stereo stuff in the work truck. I had to drive a Ford F-650 this summer when delivering drywall to a construction site. The thing had no stereo, the windows would pop out of place when you rolled them down, a tap on the brakes would cause the whole truck to rattle, and to go 50km/h you're in 5th gear (5 speed) at 2,200rpm or so. It was a beast... could use a deck to make it all better :P

[SteveXs2]

I'll post this here since I've been whoring the audio questions lately.

I've got the 380W RMS Pioneer amp right now and looking at my options for a sub (can only afford one and maybe a box).

- Clarion 10" (350W RMS)
Not sure exactly which model yet, but I'll find out tomorrow when I visit the custom audio shop here in town. See if he has any pre-made boxes, too, because I'd like to get the volume close to what's recommended for the sub.

- Kicker CompVR 12" (400W RMS)
Couple years old I think, a guy in a neighbouring city is selling it for $75 Canadian. Not too bad of a price after the $20 or so in shipping. Would need a new box.

- JVC Warren G Signature Series 10" (300W RMS I think)
$80 used at a local store. Seems like a pretty nice sub, hard to say how it's been used though. I'd be overpowering it quite a bit and I don't really want to risk wrecking the sub, but I doubt that'll happen because I won't have it too too loud.

- Sony X-Plod 12" (375W RMS)
I remember reading on here that the 10" X-Plod pounded really really hard, which isn't really what I'm looking for, so I'm wondering if the 12" may be a bit different. I can get it from Wal-Mart or Canadian Tire so it'd be easy to return if I don't like it. Would need to get a new box if I went this way.

But what thing I've been thinking about lately... should I go with a 10" or a 12" considering I want sound quality, not blow-my-ears-out sound pressure.

[SteveXs2]

*Bump*

Store isn't open today, will be open tomorrow... any opinions? Please post.

[SteveXs2]

Don't think anyone's reading this anymore, but I'll post it anyway.

I bought a Phoenix Gold Octane R10 today. First I bought the dual voice coil 2 ohm model (ZR10) and had it wired in series so it was 4 ohms, but couldn't get the thing to move at all. After taking it to a friend who couldn't figure it out, I brought it back to the guy I bought it from and after some testing he found out one of the voice coils was faulty. So, bye bye to that one. And then the guy offered me a single voice coil version of close to the same sub (R10). Had I known he had a single voice coil version tucked away I would have bought it in the first place. So I got some $20 back because the sub was one-step down from the ZR10, and after a really confusing discussion we had some laughs and I left happy.

[SteveXs2]

I bet I'm getting annoying by now. I bought a Bassworx Hatchback-style 10" sealed box (0.75 cu.ft.) for the R10 (recommends between .7 and .9. I really like the sound.

At first it was screwed though, and my sub was pulsing when there was no volume. I first checked the ground and it was fine, then checked my RCA and found that it was crushed by my seat. Bummer, but I went and got a new one and this sub pumps now :D I love it and can't wait until it's in the trunk (need a new tail light first) because then it'll really have a lot of potential. The sound quality is amazing at listening volume, I love it.