[Lateralus]

Hey,

I've finally gotten around to replacing the stock speakers in my Buick Park Avenue. I've replaced the door speakers with Rockford Fosgate HPC2205s and the rears with Eclipse SP8994s. And of course, since I'm running them without an amp, they're not sounding a whole lot better than the Buick's stock Concert Sound II speakers.

So, I need an amp. But I'm new to this car audio thing and don't really know how much wattage I need. I'm looking to do this on the cheap. Only reason I replaced the speakers in the first place was because I found the Rockfords on sale at CarDomain for $38, which led me to find the Eclipse speakers Open Box at a local car audio shop for $120.

Any suggestions?

FYI: I'm running a fairly basic low-end Sony deck that I installed a few months back; 4x52w.

[Tuoder]

Just match the RMS wattage. If you get an amp that puts out more than the speakers can handle, turn the stereo all of the way up, and the amp all of the way down. Turn the amp up slowly until you start to hear distortion from the speakers. Turn it back down until you hear none and you are set.

Oh yah, and sony lies on its amps. They are weaker than what the box says.

[zerostar]

I would get something around 100-150watt x 4 channel, as far as setting it up, with a mediocre deck you will need to turn it up until you hear distortion, then keep turning it down until the sound is clean, then do the amp the same way.

[Spliffdaddy]

Firstly, ignore any specifications on 'maximum' or 'peak' wattage. These have no standards of measurement. Look instead at the 'RMS' output power rated at 20-20000HZ with a total harmonic distortion (THD) of less than 1%.

Something on the order of 25watts per channel when rated as described above would be more than enough to drive almost any speaker (not subwoofers, though) loud and clear. I know it sounds funny to suggest that 25 watts will be better than the '52watts' (peak watts 100-20000HZ @ 10% THD, no doubt) your Sony deck claims to output - but that Sony deck is probably doing good to produce 8watts RMS 20-20000HZ @ less than 10% THD.

The lower frequencies require MUCH more power to drive the speaker cone effectively. That's why a lot of amplifier specifications will 'cheat' by NOT listing their output power across the entire frequency spectrum. You want to know what the output power is - in RMS - from 20Hz thru 20KHz and with a deviation (THD) of less than 1%. Human ears are sensitive things and they can hear THD of 5% or greater. THD is the deviation from a totally flat response across the entire audible frequency range and is measured in dB. edited: that's a technically incorrect definition.

RMS indicates that the amplifier can output that amount of power at any frequency range indefinitely. So, a 25watt RMS output would translate into 250watts or more 'peak' (intermittant) power.

That being said, I'd probably buy a Rockford Fosgate amplifier that was rated at 15 - 25 watts per channel (using the method described above).

If you want your system to be twice as loud then you will need to have 10X the output power. It would require 250watts to be twice as loud as 25 watts. Human ears don't work in a linear fashion when it comes to sound pressure.

Back in the early 90's I competed in autosound competitions with my '92 Nissan Maxima. I didn't do SPL, but, instead competed in sound quality events. I've heard 50 and 100watt systems that would blow your mind in sound pressure and clarity.

I currently use a Sony MobileES four channel amplifier rated at 40watts per channel - and it's ungodly powerful in my S-10 pickup.

[Lateralus]

Thanks guys.

What do you think of this Rockford Fosgate?

[Spliffdaddy]

That's an awesome amplifier. Total overkill, actually. But then, power doesn't really blow speakers - distortion does. And it really doesn't have any distortion

You could always add a subwoofer (or a pair of 4ohm subwoofers in parallel = 2ohms) and that amplifier would totally rock your world.

If your goal is to add a subwoofer in the future, then that's an excellent choice for an amplifier. If not, then it's total overkill for a standard 4 speaker system.

edited: heh 14 pounds. That's like a bowling ball.

By the way, I'd use the high pass filter on the speakers. Anything smaller than about 8" won't have the cone excursion needed to reproduce frequencies under 100Hz audibly. Try to keep 2 channels unused for the future subwoofer addition. Either by driving the left speakers from one channel and the right speakers from another channel - OR - by trying to keep a pair of speakers driven by the Sony deck (I know it might suck, but it might not). That amplifier will output twice as much power into a 2ohm load, so doubling up speakers (4ohm) on each channel won't result in any power decrease whatsoever. If you can keep 2 channels of the amplifier dedicated to the subwoofer, then you can bridge those channels into a single channel that would yield 200watts RMS into 4 ohms - and likely double that into a 2ohm load (2 X 4ohm subwoofers). It might not be rated to drive a 2 ohm load from a set of bridged channels, but I guarantee it would do it without a problem....and potentially yield something on the order of 350-400watts while doing it.

When I competed 10 years ago the way to win was to enter a bracket of 75-100watts. Since the brackets were based on 4ohm power output, we would simply drive the amplifier(s) into lower ohm loads. My system used a single 2 channel amplifier rated at 98watts @ 4 ohms. BUT it would drive loads as low as 0.5ohm and produce almost 800watts RMS while doing it. Having only 2 channels meant I needed to use a lot of passive filters to regulate the frequency range for each speaker. Typically I used a pair of compression horns ($!) for the highs, a pair of 6.5" for the midbass drivers, a pair of 8" door mounted bass speakers and a pair of subwoofer in a 4th-order bandpass enclosure.

I stopped competing when Rockford Fosgate released its "Symmetry" system that was basically a digital signal processor that could be a crossover, balanced line driver, digital delay, and whatever you wanted - provided you plugged in the right card. I couldn't afford to scrap my entire system and buy a $2-3000 Symmetry system - and start all over...just to compete and lose.

I used a copy of Dire Straits 'Brothers in Arms". I got some good scores using that CD. It's a completely digital recording. Something that was hard to find in the early 90's. For midbass impact, my secret weapon was the song "Bloody Well Right" from the 'Breakfast in America' CD...I forget the band's name, but everybody knows the song. edited: Supertramp

In my next chapter we'll discuss "soundstage" and how to fool your ears into believing you're at a live concert.

[Lateralus]

Well, I'm learning quite a bit.

Do you have any suggestions on a specific brand/model? I'm not looking to overkill since I know my speakers are good, not great. But I would like an amp worthy enough of hanging onto for my next car purchase. But like I said, I'm on a budget.

And I'm not too big on bass, so I'm pretty sure a sub wont be entering the equation.

[Lateralus]

BTW; Will an amp come with higher guage wiring for the speakers or is that something I'd need to purchase separtely? Will my speakers actually require anything more than stock wiring?

[Spliffdaddy]

http://www.rockfordfosgate.com/produ...p;locale=en_US
500 W x 4 @ 4 Ohms RMS
1000 W x 4 @ 2 Ohms RMS
2000 W x 4 @ 1 Ohm RMS
3750 W x 4 @ 0.5 Ohm RMS
2000 W x 2 @ 4 Ohms bridged RMS
4000 W x 2 @ 2 Ohms bridged RMS
7500 W x 2 @ 1 Ohm bridged RMS
Total Power 15000 Watts

omfg. It ships in May. I've got a month to come up with $20,000. You could always use it to arc-weld a truck chassis.

Anyhow, it appears that the 4-channel Rockford Fosgate you mentioned is the least expensive model they make. Mostly because their least expensive model is still a high-end piece of equipment. I'm glad to see that the folks at Fosgate haven't lowered their standards over the years. Absolutely awesome hardware.

Suck it up and spend the required cash on an amplifier. They last forever and you can move it to your next 3 or 4 cars. My Sony amplifier is 11 years old and it's been in five different vehicles. It *still* kicks ass. It wasn't inexpensive, but as it turned out it was the best value of any electronic component I've ever owned. So don't skimp on the amplifier. CD/tuners and headunits improve almost monthly - but power amplifiers don't. Until the laws of physics change, anyways.

Just stick with a name brand that has a good reputation - and doesn't mind showing you their 'true' output power specifications. The electronic components inside an amplifier are high-dollar stuff. There is no way to build a good amplifier for less than anybody else can. So beware of those that claim to be able to do it.

On a related note: Sometime around 1995 the employees of Rockford Fosgate in Arizona split a multimillion dollar Powerball jackpot. If I remember correctly, there were something like 22 employees - and NONE of them quit their job. That's loyalty. And a love for what they do.

[Spliffdaddy]

Originally Posted by Lateralus

BTW; Will an amp come with higher guage wiring for the speakers or is that something I'd need to purchase separtely? Will my speakers actually require anything more than stock wiring?

The amplifier won't come with any wiring. You'll need something on the order of 8gauge braided copper for the amplifier itself (prepare to spend at least $40 for a wiring kit that includes a fuse, terminals, and at least 12 feet of 8Ga. power cable and a short length of 8ga for the ground). Your factory speaker wires are probably alright.

Check out some previously-owned amplifiers. You'll save some money and they don't really wear out anyways.

[Lateralus]

It's always nice to ask for advice on something and run into somebody who is truly passionate about what you're asking about. You've been a great help.

And you're right. I'll shell out for a nice amp. I was already looking at used on eBay figuring there wasn't much to lose, especially given the savings. Hell, the P4004 RF that I linked to above @ $240 is going for around $160 new and boxed from a number of eBay sellers.

Heh. This whole situation is funny. I used to make fun of people who sank a ton of money into car audio toys. The only reason I went about doing anything was because, during my ownership of it, my Buick never had sound in the driver's side door. I had figured it was a bad speaker to I shelled out for the Rockford 5.25s and it ended up being the wiring in the door boot that was the problem all along. Then I decided that having a nice pair of Rockfords in the front drowning the stock 9x6s in the back didn't make much sense to I shelled out for the Eclipses. And now, hearing very little difference from the stock speakers (other than the addition of a working driver's door speaker) due to insufficient wattage, I'm looking at an amp.

Oh well. Doing all this myself is turning out to be fun.

[Spliffdaddy]

Yeah, you'll be addicted before it's all over.

It all started for me when I visited my cousin one summer in 1988. He had a Ford Escort GT that had a single 15" subwoofer and some other decent equipment. I was blown away. It actually gave me goosebumps - made the hair on my arms stand straight up. Until then I'd never heard distortion-free reproduction of music at high volume level. Hell, it's still a rare thing - especially at nightclubs and concerts. Maybe I'm too critical, but distorted bass makes me want to turn the music off - or leave the scene. Anyhow, my cousin kept saying how his Escort didn't really sound all that good. I was in disbelief. Until his friend showed up in a IROC-Z. Holy cow. It was a long time before I heard anything as good as that system. I'd rather listen to something that good than to bone a hot redhead.

I spent the next 6 years trying to achieve the same sound quality in my own car. I learned a lot and spent a lot of money doing it. At first I took the easy way out and used something like 4 amplifiers and a total of 1,500 watts of power. Four 12" subwoofers in the trunk left no room for even a sack of groceries. The headlights dimmed to the beat. So then I installed some stiffening capacitors and a high-output 200amp alternator from an ambulance. Not an easy task in a Nissan Maxima. I gutted the interior a dozen times in order to run cables and install speakers. My wife wasn't impressed with the amount of time I was spending - not to mention the money. I'd sit in that car for hours and just tune it and listen and tune some more. I'd have to drive down the street to an empty parking lot because the neighbors kept calling the cops on me. And since I was usually smoking weed, having cops show up was never a good thing.

So I decided to get rid of all the stuff and just use a minimal amount of equipment. It became a challenge to achieve the same level of volume and clarity it once had. But I got it all worked out. I spent many hours at my job at AT&T using their computers to design subwoofer enclosures and passive crossover networks. I learned all about Theille/Small parameters and inductors and capacitance and a ton of other things I had no business knowing. I was kicking everybody's ass using a 100watt amplifier a single 12" subwoofer, a pair of tweeters, and a pair of mid-bass drivers. People would brag about their 1000 watt systems with multiple 15" subs and then they'd sit in my Maxima and and just stare in disbelief at what 100watts could do. I never heard another system that was half as good as mine. Until I entered a sound quality competition and came in 13th out of 15 entries in my bracket. The comment cards I recieved from the judges made me want to cry. While my system sounded good to the untrained ear, it sounded like ass to a trained ear. It had no 'soundstage' and the frequency response was nothing near flat. It was loud and it was clear, but that wasn't enough.

I spent the next couple of years tuning the system and swapping/moving speakers until I got it right. And damn what a difference it made. I could close my eyes and I'd swear I was sitting in the front row of a concert. I could hear the drummer behind the guitarists and I could tell when the vocalist walked back and forth on the stage. I could hear everything! Ears don't lie. So you have to trick them into believing what they're hearing is real. It's all about timing and location. I came in 4th out of 25 entries in a statewide competition. The top 3 winners all had sponsors.
Then, soon afterward Rockford Fosgate's Symmetry computer system became commonplace. It could do instantly what took me years to do manually. I was beaten by technology. Any dolt could now do better than me with 2 grand and an hour of time. I spent thousands of hours doing the same thing.
I proved to myself that I could do it, and then I lost interest. Kinda the story of my life repeated time and time again.

Good luck with your stereo system. Hope your wife understands...