How about these amps

[miata1.6]

http://www.overstock.com/cgi-bin/d2....ROD_ID=1045144
or
http://www.overstock.com/cgi-bin/d2....ROD_ID=1147975
or
http://www.overstock.com/cgi-bin/d2....ROD_ID=1804462
I like the look of the MDX one but the other two are bridgeable... Im not sure what that means but isnt it good? I need it to hook up two DUAL 10" subs (150 watts RMS) and then two speakers in the doors, and if possible two more in the back. are these any good.

[NAVY IC]

Here's the specs for the (Nitro BMW 483). They're not complete, but they appear to be ok for an average "200" watt not 1000 watt amp.
Even with a 15 volt charging system, this amp will blow it's fuses once it have enough input power to produce around 600 watts max,
and don't even think about what the distortion levels will be like at that point. I can look deeper for more specs, but I know they'll be the same for all those amps
Number of Channels 4
RMS Power (4 ohms) 50 watts x 4 chan
RMS Power (2 ohms) 75 watts x 4 chan.
RMS Power (1 ohm) Not Stable
Bridged RMS Power 150 watts x 2 chan.
Peak Power Output 1000 watts
Min. Impedance Unbridged 2 ohms
Min. Impedance Bridged 4 ohms
THD @ Rated RMS Power 0.03%
Speaker Level Inputs Yes
Amp Preamp Outputs No
Built-in Crossover Yes - HP / LP
High-Pass Crossover 50 Hz - 1 kHz
Low-Pass Crossover 30 Hz - 250 Hz
Subsonic Filter N/A
Signal-to-Noise Ratio 95 dB
Channel Separation N/A
Bass Boost 0 - 18 dB
Bass/Gain Remote N/A
Fan Cooled No
Fuse Rating 40A
Warranty 1-year Manufacturer's

[RickwithaTbird]

bridgeable is good when you don't want to use all your channels. Otherwise it doesn't matter. I wouldn't buy those amps. I have one suggestion....



http://cgi.ebay.com/NEW-HIFONICS-TX4...QQcmdZViewItem

[NAVY IC]

Originally Posted by RickwithaTbird

bridgeable is good when you don't want to use all your channels. Otherwise it doesn't matter. I wouldn't buy those amps. I have one suggestion....



http://cgi.ebay.com/NEW-HIFONICS-TX4...QQcmdZViewItem

This spec. sheet that's given is more marketing than technical, but giving it the quick once over,
I can see marketing is probably one of the sacrifices they used to meet their price goals.
For example 220w x 2 bridged @4ohms should give 110w x 4 @4ohms and 220w x 4 @ 2ohms.
I'm willing to bet it got to do with having to use tighter regulation to protect it's cheaper components,
(Better tolerances means more $). That's not really the best design choice for sub amps using class a/b circuitry.

And another thing, why would they market their world class high pass filters down to 10hz when the line before it says sub-sonic filters...??
If I can remember right, the sub-sonic range starts at about 20-25Hz, and cuts everything below it because it's more of a sensation than it is
musical info down in those freq. ranges. I would say this amp is more hype than anything else, but that's without bench testing it personally



a/b Class Design
4 Channel Car amplifier
110 watts x 4 RMS @ 2 ohms
220 watts x 2 BRIDGED RMS @ 4 ohms
High-Speed MOSFET Output
Mosfet Power Supply
Simpatico Coil Design makes increased accuracy
Heat-Sink Design destroys hot air and lets in cold air
Fully Adjustable Crossovers
Sub-sonic Filters
High Pass Filter: 10 Hz - 1.2 kHz
Low Pass Filter: 50 Hz - 150 Hz
Variable Bass EQ: +18 dB @ 45 Hz
Adjustable Input Sensitivity: 200mV - 6V
Frequency Response: 10 Hz - 30 kHz
Power and Protection LEDs
4-Way amplifier Protection: DC, Short, Thermal, and Overload
Silver RCA Line-Outs
FUSE RATING: 30 AMPS

[miata1.6]

so should I use a seperate amp to power my subs?

[NAVY IC]

Originally Posted by miata1.6

so should I use a seperate amp to power my subs?

The quick answer is no...I can give you a better answer with more info.
Do you want all of your speakers amplified or just your subs...??
Besides the Duals, what else is in your system...??
What's your budget like, are you buying equipment based mainly on price...??

[pimprolla112]

1 mono block or small 2 channel bridgeable, and a small4 channel for subs and speaks. A 4 channel gets 2 speakers and the sub for space and cost this is a nice option considering the majority of the sound should come from the front of the car. And the last option is to look into a 5-channel amp alot of guys dont suggest these but they are a good deal for the money if you feel like dealing with all the wires. I have one in my girls car sounds pretty kick ass hooked up to a 12" MTX, yeah i had it laying around.

Seperate amps are always better more control over the sound and everything gets the right power (dont have a draw on the speakers cause the sub hits).

[sr20de4evr]

Watch out for any amp where the rated "peak" or "max" power is more than twice the rated rms power.

Originally Posted by NAVY IC

I can see marketing is probably one of the sacrifices they used to meet their price goals.
For example 220w x 2 bridged @4ohms should give 110w x 4 @4ohms and 220w x 4 @ 2ohms.

No, it shouldn't.
220x2 @ 4ohm IS 110x4 @ 2ohm, by definition, which should be 55-80x4 @ 4ohm.

Originally Posted by NAVY IC

That's not really the best design choice for sub amps using class a/b circuitry.

Why not? The only downside is efficiency (which apparently you don't care about since your class d sub amp has a lower efficiency than many class ab amps out there, probably including this one), which at this power level doesn't really matter. What's wrong with having a better frequency response, more options for the future, lower distortion, and better sound quality?

[PaulD]

Miata ..... I have a relatively simple system running off of a single 4 channel amp. If you don't need lots of power (like for a large sub) then it's all you need.

[NAVY IC]

Originally Posted by sr20de4evr

1.) Watch out for any amp where the rated "peak" or "max" power is more than twice the rated rms power.

2.) No, it shouldn't.
220x2 @ 4ohm IS 110x4 @ 2ohm, by definition, which should be 55-80x4 @ 4ohm.

3.) Why not? The only downside is efficiency (which apparently you don't care about since your class d sub amp has a lower efficiency than many class ab amps out there, probably including this one), which at this power level doesn't really matter. What's wrong with having a better frequency response, more options for the future, lower distortion, and better sound quality?

1. I see your selling some ED equipment in your sig...check out the numbers for the Elemental Design NINe.2 and the NINe.2x....imparticularly the rated power with "2" channels @ 4ohms and the rated power bridged to "1" channel @ 4ohms....do you think this is a company we should watch out for
2. Reference item 1
3. Reference rule #1 of Energy and Thermodynamics, Kirchoff's Current and Voltage laws, and Ohms Law(s)...

Because amplifier efficiency, (watts-out / watts-in), is directly proportional to the capacity of internal energy storage devices, (capacitors), efficiency is not automatically indicative of quality (ex. class a amplifier).
Regardless of it's efficiency, the class of amplifiers denotes accuracy of reproduction. What I'm saying is best demonstrated by the proliferation of high quality space saving designs-vs-the super huge garbage amps.

[sr20de4evr]

Originally Posted by NAVY IC

1. I see your selling some ED equipment in your sig...check out the numbers for the Elemental Design NINe.2 and the NINe.2x....imparticularly the rated power with "2" channels @ 4ohms and the rated power bridged to "1" channel @ 4ohms....do you think this is a company we should watch out for
2. Reference item 1
3. Reference rule #1 of Energy and Thermodynamics, Kirchoff's Current and Voltage laws, and Ohms Law(s)...

Because amplifier efficiency, (watts-out / watts-in), is directly proportional to the capacity of internal energy storage devices, (capacitors), efficiency is not automatically indicative of quality (ex. class a amplifier).
Regardless of it's efficiency, the class of amplifiers denotes accuracy of reproduction. What I'm saying is best demonstrated by the proliferation of high quality space saving designs-vs-the super huge garbage amps.

1 - No, they don't even advertise a peak power rating, so what I said earlier doesn't even apply here. Now while I don't agree with their ratings for the nine.2 (4ohm bridged is rated at a higher distortion than 2ohm stereo, which is why they don't match up), the nine.2x looks perfectly fine. If you think it's bad because the power doesn't double when going from 4ohm stereo to 2ohm stereo, or quadruple when going from 4ohm stereo to 4ohm bridged, NO amp will, it's physically impossible, even the ones that say they do don't.

2 - ?

3 - What rule is that? I've taken mass and energy, thermodynamics, heat transfer, and electronics 1, 2, and 3...and none of them have to do with what either you or I said in #3.

Amplifier efficiency has nothing to do with internal capacitance, nothing at all, I have no idea where you're getting this from. The internal capacitance is used to hold the rail voltage up in between power supply pulses, and in some cases to hold it up temporarily during moments of heavy current draw, again nothing at all to do with efficiency. Efficiency, apart from topology, is mostly based on the design and the parts used in the power supply (other than the capacitors) as well as the design of the output stage. You're right, efficiency is not indicative of quality at all, that was not my point. My point is that the ONLY advantage of a class d amp IS efficiency (other than price, sometimes), that's it. When comparing equivalent amps, the class d will have a worse frequency response (99% of the time), lower damping factor, and more distortion. While normally these drawbacks aren't audible, my point is that if you compromise efficiency, there's no real reason to go with a class d amp anymore. You said that he should go with a class d amp instead of a class ab amp and I asked why. Not only is the power consumption going to be extremely close at those power levels (which would normally be the only reason to go with a class d in the first place), apparently efficiency doesn't matter to you because your class d amp has an efficiency comparable to a typical class ab, making it all but useless.

[RickwithaTbird]

I haven't taken all those classes, but I do know very well how to install a stereo system. I don't think I gave a bad recommendation, nor a great recommendation, but let's face it, it was only a suggestion. A quick little thing I did to help the poor guy out a bit. 110 x 4 @ 2 ohm, and 220 x 2 @ 4 ohm seemed ok to me. Can we just help the guy out and give him a better suggestion if you have one?

[JunkTitleGolf]

I would say a power acoustik amp. I have one and it is working great. And for the price it was a great buy.

[pimprolla112]

Power apoopstik. Cant remember who made that one up but its about right. Profile and hifonics are the best value amps hands down. Granted there not rated at 100% power capacity you can get a 4x75 for less than 100 off ebay. IM pretty sure most of the more knowledgable guys will agree that profile makes great budget amps.