mdb_foxmx

That question may sound stupid. Usually, the answer to such a question is "because (item/s) is/are crappy." But looking over the specs for a few amps, I find that the signal-to-noise ratio of profile amps is usually pretty high compared with some other amps, and the THD is really pretty low compared to others (like the infinity 7541a @ 1%THD). But the profile amps are much cheaper...

I'm not a genius with this stuff, so could someone clarify?

Thanks in advance.

Mystic3030

A saturn or hyundai looks good on paper too.

Sinisterdexter

iTrader: (3)

In that respect, so do Civics.

Just kidding.

Mystic3030

haha, yeah, our cars suck *** too...the only positive point of them is that they last for a while and they get good fuel economy...but I still can't wait to get rid of mine.

mdb_foxmx

...ok...three posts in and the subject has changed? lol. Anyone care to qualify the statements about the profile amps? Would anyone like to recommend another brand of amplifier? One thing though...if you recommend an amp, plz say why. When people say, "This is a good amp, you should get it", but don't really say why, then I don't really have anything to say about it other than you recommended it.

nick95673

iTrader: (13)

generally cheap car audio will be more likely to stop working within 8 months.

mdb_foxmx

Alright, well, what about audiobahn? Their amps are not cheap, and their specs are still pretty awesome...

nick95673

iTrader: (13)

Audiobahn is ok. What are you looking for? looks? bass? highs & mids? If you already have speakers what will this amp be pushing? Whats your total budget? Pay for install or diy? Already have an amp kit? I would stay away from the spec sheet. It has good useless info. Everyone will tell you what brand amp is the best and generally everyone will recomend what they have. I have a kenwood 4-channel and it is good it does what I want it to. If I had the money I would have an Alpine 4channel. I also have a Fosgate 1 channel. I went with fosgate because they generally under value the power of their amps. Most of their amps have about 15% more rms than what they are rated at.

mdb_foxmx

Well, the dilemma is this:

I'm looking at doing a complete overhaul of my audio system. I work at a place that sells polk audio for the home and for your automobile. Employers of polk dealers get accomadations through polk, which usually drops the price of equipment by half. So I'm looking at buying the following stuff:

http://www.crutchfield.com/S-Z24za38...6500&s=0&cc=01
http://www.crutchfield.com/S-Z24za38...B690&s=0&cc=01
http://www.crutchfield.com/S-Z24za38...101D&s=0&cc=01

So, I need to find a way to power these things. If I could find a 4-channel amp that would supply about 100W to each of the door speakers and each of the rear deck speakers, and then bridge to power the sub at about 300W or more, that would be ideal.

I'm not looking to blow off someone's head here. I just want to have very clean sound. I read that the infinity sub above is very tight and responsive, which is exactly what I'm looking for. The polk speakers aren't the best in the world, but I'm getting them for about half the price listed, and they will have much better sound than some other options.

I know spec sheets shouldn't be the only thing you consider when you buy an amp (or anything, really). But, I wouldn't say all the information is totally useless. A change in THD from 2% to 0.1% is easily noticeable. If you're interested in clean, natural sound, THD is important. If you're looking for a sub that will make all your speakers really, really loud, THD probably isn't your main concern. Also, the THD for me is only important for the components and the rear 3-ways. I could really care less about THD or signal-to-noise on the sub. I don't think I'd notice any difference in those parameters through a sub.

Mystic3030

Well what is your budget? A JL 300/4 and a JL 500/1 would give you what you want as far as power and quality are concerned. I have two JL 500/1's, one is 5 years old and one is 4 years old, and I have had ZERO problems with both, they are running strong still and sound amazing. They have excellent built in parametric equalizers and a good crossover with a subsonic filter. Those retail at $550, and can be found online for about $400 I believe.

I also have a PPI amp for my highs that is 3 years old, and sounds fantastic, however one of the channels fried about 8 months ago. The amp retailed at $1200 when I bought it, and Directed rebuilt it completely for $120 about 6 months ago for me. It's no longer in production, but in general PPI products are good.

Devani

iTrader: (2)

THD should be less than 0.1% if you want clarity...well you know that....

Yes Signal to Noise Ratio is important too because it means that the noises from the everything else will be rejected and only the true signal will be picked up....and amplified....although there are 2nd and 3rd harmonics come into play....it is negligible....

The sensitivity is also important factor when deciding. Generally high end audios achieve 100 dB or better....for subs...its little lower than 100dB....for the speakers listed............they are fine.....

Power Range of XX-XXX Watt RMS is a term that is meaningless....

cross over network has 12dB/Octave which is average....high end ones have 18dB/Octave....number is the ability to filter at the faster or slower rate....well the higher then number the better..but it is only used in very expensive systems....so it is sufficient to use and not distingushable...

Get the sub box although it says free air use...not recommended.....

as for the amp....there are million different options.....If money is not limited get separate amps for each set of speakers....

you are lucky to work in a place that sells stuff...

My uncle owns a distribution center for all electronics in LA not a retail store....I can get anything in store for free.....whenever i go visit....i bring stuff.....and I can listen and test each individual products

mdb_foxmx

As for the budget, I'm not really sure. I'd like to get everything powered for under about $600. Since the door/rear deck speakers are 100W rms, I'd be able to take as low as 75W to each of those, so if I could find an amp that would put out 150W @ 2ohms per channel, that would be satisfactory. Of course, getting the full 100W to each speaker would be ideal. As for the sub, I'd like to get at least 300W to it, and would really like to do more than that. Also, as I said, if I have to get another amp for the sub, I don't really care so much about the specs, just so long as the output is reliable. I don't think it's necessary to have a super-high signal-to-noise there, or a low THD.

If I could get all this in a single amp, that would be great, but the more I look around, the less promising this approach gets. I'd be fine with a good 2-channel amp for the front/rear speakers (low THD, high sig2noise) and a decent 2 channel or mono amp for the sub.