Stereo amplifier and wire choices

[Ed]

I'm working on upgrading the stereo in my car and have made a custom speaker box that fits behind the seats in front of the shock towers. I put in a pair of brand new Sony Xplod 10" subwoofers with 300W rms and 1200W max output.

What size amp should I use with these speakers? Is there a particular wire I should use to go from the amp to the speakers? Guage, construction etc..?

I currently have a Sony CD player with 5" speakers in the front and 6X9's in the rear. Should I use some type of electronic crossover even if the 5" & 6X9's won't be going through the amp?

Thanks

[hls30.com]

Ed,

Because of the listening environment, and the fact that the amp will be less than 10 feet from the speakers, I don't think any wire will offer any thing that will make any difference over what standard 16 gage speaker wire from Walmart can do(other than cost more).

It is kind of like comparing good standard cables and the premium gold plated cables for your computer-unless there is a corrosion consideration, you can pay more to feel better, but you won't get noticeably different results.

On a low level signal(preamp level) shielding can be important, but on a line level wire in a typical setting, shielding is nothing more than an overpriced unneeded option.

While a crossover is not absolutley necessary when using an amp to drive a pair of subwoofers, unless the head unit has a subwoofer output, or the amp has a subwoofer switch, I would add a couple of appropriate inductors to block extraneous signals form the subwoofers for the best of their intended sound.

I would also suggest an amp rated two to four times the power of the head unit. Assuming you did the math to design your subwoofer enclosure for the subwoofers you chose, you will be able to make more bass than you are likely to use, even though bass is where the real power in a music system goes.

You may find putting an appropriate capaitor on the 5" drivers will improve the sound as well.

Will

Will

[Ed]

I would also suggest an amp rated two to four times the power of the head unit.

IIRC the head unit is 4 x 25w. Wouldn't I need to pick an amp the won't overpower the speakers? Since each speaker is rated at 300W rms shouldn't the amp be at most a 600w?

[hls30.com]

No, the head is rated at 4 x 25 watts, that is 25 watts output per channel, making it a four channel 25 watt amp, not a 100 watt amp. You need about a 100 watt amplifier.

Manufacturers quote total wattage to make it seem to have more power than it actually does. Unless you bridge the outputs(If that is possable on the amp in question), you still have a 25 watt amplifier.

The ratings on the speakers are not necessary to match, they are for maximum suggested clean power. I have a set of massive set of folded horn Klipch speakers that are rated at 1000 watts each, with 100 watts I can push them to my pain threshold! I would not want to send even 300 watts through them!

The point is you do not have to supply the speakers with maximum power to get great sound out of them.

Will

[Ed]

Thanks Will,

Here is a link to what I was looking at. I want to stay Sony since that is what my head unit is and my speakers. The color is right to. You know me It's gotta match the rest of the car:). What do you think?

http://cgi.ebay.com/ebaymotors/Sony-Xplod-Amplifier-1000w_W0QQcmdZViewItemQQcategoryZ38638QQihZ005QQitemZ150050134349QQrdZ1

[hls30.com]

It looks fine, you will not need a crossover or inductors with that amp.

Be sure he sitll has the accessories(manual).

Walmart sells the same amp for $142, new in the box-with free shipping to your local store if they don't have it in stock.

Will

[240ZX]

Just a note regarding the power amp output......at a minimum you will want no less than 100 watts. If you think you will be protecting the speakers by purchasing an amp of less than 100 watts, you are mistaking. With an under powered amp, when asked to perform at maximum output, will do what is called hitting the rails...in other words, the regular sine wave output will be turned into a square wave form because it has reached its maximum output. A square wave will fry the voice coils in your speakers in short order.

Tom

[Walter Moore]

Let's see... 1000W / 12V = 83A.

Hope you have upsized the alternator:classic:

Oh, and I would recommend at least a #6 AWG wire for power...

[hls30.com]

Just a note regarding the power amp output......at a minimum you will want no less than 100 watts. If you think you will be protecting the speakers by purchasing an amp of less than 100 watts, you are mistaking. With an under powered amp, when asked to perform at maximum output, will do what is called hitting the rails...in other words, the regular sine wave output will be turned into a square wave form because it has reached its maximum output. A square wave will fry the voice coils in your speakers in short order.

Tom

This is true of many amps, but you will hear the problem long before any damage is done. Also not of all amps exhibit this situation-it is completely circuit dependant. Better amps actually do not "Clip" which is the term used to describe the situation Tom brought out. The first amp that I experienced that had the non clipping circuitry was actually a home amp made by Proton, it was followed closely by their automotive version. The circuitry proved to be more expensive to produce than the company charged for and the company went out. I had that amp for years, and it was clearer than the Carver 9lb cube I had even though it was rated at only 40 watts and the Circuitry allowed it to perform like a 160 watt amp. Being in the company of Carver at that point in time was an impressive feat for an amp costing less than $300.

Ed, if you were a 20something into making the chrome on your car wear holes in your paint from blasting bass, I would have directed you to something different, but in a Z unless you are willing to sacrifice some of finish of your stock interior, you simply can't get proper placement of drivers to deliver outstanding sound.

I am insulating the bejesus out of my Z, using a four product approach incorporating absorbtion, conversion and reflection of sound waves. I expect to have a Z that is quieter than a new top of the line Lexus.

I will be putting in a quite nice sound system after I prove my car is as devoid of roadnoise, resonances, and the like as I expect it to be. When everything is proven to work, as expected, I will be writing up an article.

Will

[TomoHawk]

As a rule of thumb, the audio (experts) will tell you to get an amp that has more power than the speakers you will be driving. The reason is because when you turn up the power all the way (to make it loud) the sound gets distorted, from clipping or whatever, and it sounds bad. With the extra amps, you will only have to use partial power, and the sound will be much nicer, the quiet parts will not have any hissing, etc.

[speedyblue]

Find an amp that can be birdged to around 1x400w RMS at a 2 ohm load, then you can run both subs (assumed to be 4 ohm) in parallel. The other option is to by an amp that will give 2x300w RMS at 4 ohms and run a sub per channel. At that power you are probably looking closer to 4 gauge power wire. And don't forget, run RCA's up one side of the car and Power lines up the other. Any amp should have a cross over built in. A lot of headunits have them built in too. I can cut the treble from the subs and the bass from the rest of the speakers from the headunit, and adjust the sub gain level and it;s not even a high end headunit. Enjoy it!!

[Zs-ondabrain]

I am an Audio Professional and even you guys got ME confused. TOO much to reach and you lose the point.

1) The Sony 1000 watt amp will be JUST FINE.

It's a sony and at that price, there is NO WAY you will get a TRUE 100 watts out of it. NO worries of blowing up the subs from too much power. No worries about under powering the subs.

2) Like speedy blue said, Bridge the amp to get the max power out of it and drop the load down to 2 ohms. Usually achieved by using the left channels positive and the right channels negative. unless it is a D-class amp, at that rate, it's already done for you. FOLLOW THE INSTRUCTIONS!!

3) on the speakers, you'll want to connect the Positive from the Amps left channel to positives on BOTH speakers and the amps right negative to the negatives on both speakers. This will give 2 4ohm speakers a 2 ohm load at the amp.

4) make sure you set up the cross-over on the amp. many buttons, lots of choices. Turn the gain knob all the way down, then turn the stereo up as far as it will go, then slowly turn up the gain untill the subs start to distort, then back off on the gain a little.

That will keep you from EVER over powering the subs and keep the sound clean as you turn it up, even all the way.

hope this helps a little,

Dave