How to recognize a good SQ amplifier?

[ABXX49 20]

cool, sounds really good. I'll check a little bit around and read a bit more, because I have about 2 weeks before I get the money to place the order. But Sundown Audio sounds really tempting.

You can't go wrong with Sundown. Not to sound pompous, or full of ourselves here, but before you buy, ask us here. We won't try to peddle you a product, or give you false information. A bunch of good guys here.

[Duran 387]

cool, sounds really good. I'll check a little bit around and read a bit more, because I have about 2 weeks before I get the money to place the order. But Sundown Audio sounds really tempting.

You can't go wrong with Sundown. Not to sound pompous, or full of ourselves here, but before you buy, ask us here. We won't try to peddle you a product, or give you false information. A bunch of good guys here.

Cheers!

[Dammed 12]

Will do, and yeah, I have to say, this is the forum with the most information and helpful people I have seen in a good while. I'm off for today, 07:00am here, need some sleep.

[todd.brust 29]

Thx for the link Impious, interesting reading. Just as a side note, regarding the amplifier class. The difference in SQ would maybe not be any different, but if you look at practical use of a amplifier, a A class with a higher efficiency would not heat up as fast as a D class amplifier. Meaning you can push a A class amplifier longer then a class D. At least that's my understanding, because the electricity that doesn't get converted to power out from the amplifier will be transferred to heat. But then again, a D class amplifier could have better heatsinks to counter affect this problem. Am I on the right track, or?

I think you got this kind of backwards. Class A is not high efficiency, at all. Class D is. Class As run much much warmer than any class D amplifier ever will. Hell, I've seen class A/B amps run hotter than any class D amp. I'm not sure what topology is going to need more heatsinking to run optimally, but I do know that every class D amp I've seen and heard, full range, or subwoofer amps, have generally run cooler than a/b amps.

[Lucky 76 5]

So, THD, S/N ratio, dampening factor, and X-over capability, any thing else to watch out for?

There's no such thing as a "sound quality" amplifier.

THD is a pretty unimportant spec to look at. Any amp worth owning (meaning anything but extreme low end junk) will be capable of operating at a level of distortion that is inaudible with music. Most amps on the market have their power rated at a THD level of equal to or less than 1%, which means there will not be an audible difference between them distortion wise. Many people mistakenly believe that THD is a "lower sounds better" spec, but the truth is that once distortion gets down to a certain level (2% or less) you won't be able to hear a difference with music. So you can ignore it.

Signal to Noise Ratio (SNR) is the same way. Any amp worth owning will have a sufficient enough SNR to be audibly indistinguishable. SNR can only even be used as a point of comparison if you know the testing conditions of the measurement. If one amp had SNR rated at 1w of power output, and another amp rated at 100w of power output, then the "rated" SNR of the amplifiers are NOT directly comparable. But regardless, it's a relatively unimportant spec and can generally be ignored.

Damping Factor is another spec that can be ignored. Many people incorrectly believe that DF is a "higher is better" spec. The truth however is that once an amplifier has sufficient damping as to not audibly affect the sound, going any higher will not yield any benefit. A damping factor of around 20 is sufficient enough to not cause an audible difference. Just about any amp on the market will have sufficient damping as to not audibly affect the sound. Damping factor thread is here: http://www.soundsolu..._1entry537161

Class A/B does not sound any better than Class D. Class A doesn't sound any better than Class A/B or D. You can not attribute any particular sound characteristics to the "class" of the amplifier, and no one has ever been able to conclusively demonstrate that the "class" of the amplifier affects the sound.

What should you look for in an amplifier?

Look for an amp that offers the most power output within your budget, has the features you need, the build quality you desire, aesthetics you prefer, fits your space requirements and has a warranty & customer service you can live with. It's that simple.

Couldnt of been said any better.

x2 - A well built amplifier is all you need. There is no audible difference when it comes to high quality amps. Spend the extra money you will save yourself on a nice set of speakers and deadening material.

[///M5 2,833]

So the best thing would actually be to buy a 6-channel amplifier, since on that amplifier you could run a active 3-way front stage?

That sounds interesting, I will probably run a active front stage in the future then, 2 or 3 way. What features do you have to watch out for? Cause as I see it, the crossovers are external right?

It depends on where you are going here. You asked for SQ which we don't like on the forum because it isn't very descriptive to your definition.

If that is truly your goal, then I wouldn't buy a 6 channel amplifier as the most important thing in an amplifier for an SQ install is power. The more the better. Spend as much as you can to get an amp with some balls, the headroom will pay dividends.

Also on the whole crossover thing. You CANNOT have an effective 3 way front stage using the crossovers on an amplifier. You are going to need an offboard processor.

-as an aside, if SQ is truly your goal you should spend WAY more time and money worrying about the install of the drivers than anything else in the system. The amps are the easy part.

[Dammed 12]

I know people don't like SQ and ""SQL"" on thi forum and I understand, because one person can like the sound, but others think it's horrible. I's a expression that's based on taste not facts. BUT as I see it, we aren't talking about speakers, but amps. And the way I see it, a sq amp can't be determined by taste, but by electrical science.

The amplifier I'm going to buy will be running two sets of Infinity Kappa Perfect 6.1, which I had running on a Hifonics zxi 6006. And from my exp, the amplifier did not have enough power to run them good enough. And if I turned up the volume, it didn't sound correct, it started to sound like they were about to blow. It wasn't a clean and crisp sound. This wasn't at a high volume, so they weren't actually about to blow.

Considering I'm going to use Infinity Kappa Perfect 6.1 which has a bit low sensitivity (90db) and can handle 100W rms. Should I aim for a amplifier that deliver perhaps 150W rms per channel? Or is 100W rms from a quality amplifier good enough?

In the beginning I'm not going active, the speakers will be run passive.

[Sir-Lancelot 216]

Get the most power your budget can handle.

You can turn the gains down and have overhead for peak.

Remember just because an amp says 100w does not mean it is sending your speakers 100w continuously. Only for a fraction of a second more likely. I am running 250w to comps rated for 150w. The cleaner your signal, the more power the speakers can take. Clipping is death, but power is good.

[Impious 1,476]

Thx for the link Impious, interesting reading. Just as a side note, regarding the amplifier class. The difference in SQ would maybe not be any different, but if you look at practical use of a amplifier, a A class with a higher efficiency would not heat up as fast as a D class amplifier. Meaning you can push a A class amplifier longer then a class D. At least that's my understanding, because the electricity that doesn't get converted to power out from the amplifier will be transferred to heat. But then again, a D class amplifier could have better heatsinks to counter affect this problem. Am I on the right track, or?

Class A is the least efficient amplifier design. They are theoretically limited to a maximum efficiency of 25% (remember, that's maximum). They also are never "off", which means they are pulling full amperage from the electrical system even at idle, with no signal input.

Class A/B is more efficient than class A. At full power, they can be in the 60% efficient range. However their efficiency worsens as power output decreases. At 1/3 power they are only about 30-35% efficient. And guess where they amplifier spends most of it's time? Here's a hint; It's not towards the full power end of the spectrum.

Class D are typically more efficient than Class A/B. Class A/B and class D efficiency can be similar at full power output, however class D don't suffer from the loss in efficiency at lower power levels that class A/B suffer from.

As to the real "question" that you posed here; An amplifier should be designed to function properly within the temperature range it will be operating in. If you have an amplifier shut down on a shorter time scale due to over heating when used within it's intended operating range and given adequate ventilation, then it's heat dissipation properties was given poor consideration by the designer and that would qualify as a poorly designed amplifier.

[Impious 1,476]

Considering I'm going to use Infinity Kappa Perfect 6.1 which has a bit low sensitivity (90db) and can handle 100W rms. Should I aim for a amplifier that deliver perhaps 150W rms per channel? Or is 100W rms from a quality amplifier good enough?

Amplifier Headroom - SSA Car Audio Forum

[Dammed 12]

Thx for the link again Impious. A lot of good info on the forum.

Well, I have narrowed down my options quite a bit.

It has come down to these amps, and the order is what I think atm is the best choice:

1. Soundstream Reference 4.920

reason: Lots of power, 4x145W rms, Hawkins Boost Control, a good review of the smaller brother: LINK, and the looks are quite nice. (note: the power is slightly over rated on the little brother, but sill quite acceptable considering the price and features IMO)

2. Rockford Fosgate Power T600-4

reason: RF quality, 4x131W rms (birthsheet data @ 14.4V)

3. Sundown Audio SAX-100.4

reason, Good rep from members of this forum, 4x100W rms, underrated power, my wild guess maybe around 4x110/120W rms. Good features and intriguing becuase it's unknown where I'm from.

The features on those three are quite the same, but Soundstream has the best with the larger range of the crossovers and the Hawkin Boost Control. The review looks good, but it's hinting to heating problems. Question here's are they still Smoke Stream?

The Rockford has lots of power as well, looks quite good, and has the same features as the Sundown amp, as far as my sleepy eyes sees it. Since it has more power (on paper at least) and because it's RF (easier to sell if I want to change) it's on 2.nd place.

The Sundown Audio amp was my first choice to begin with before I checked all the other amps, only reason it's at 3. place is because it's unknown (hard to sell) an it has a little less power then the RF amp.

What do you guys think I should go for? And please say why you think so. I have very little use for ""Sundown Audio / RF / Soundstream FTW!!! """ replies.

Edited December 30, 2009 by Dammed

[///M5 2,833]

I know people don't like SQ and "SQL" on thi forum and I understand, because one person can like the sound, but others think it's horrible. I's a expression that's based on taste not facts. BUT as I see it, we aren't talking about speakers, but amps. And the way I see it, a sq amp can't be determined by taste, but by electrical science.

The amplifier I'm going to buy will be running two sets of Infinity Kappa Perfect 6.1, which I had running on a Hifonics zxi 6006. And from my exp, the amplifier did not have enough power to run them good enough. And if I turned up the volume, it didn't sound correct, it started to sound like they were about to blow. It wasn't a clean and crisp sound. This wasn't at a high volume, so they weren't actually about to blow.

Considering I'm going to use Infinity Kappa Perfect 6.1 which has a bit low sensitivity (90db) and can handle 100W rms. Should I aim for a amplifier that deliver perhaps 150W rms per channel? Or is 100W rms from a quality amplifier good enough?

In the beginning I'm not going active, the speakers will be run passive.

Asking for an SQ amp and running two sets of Kappa's isn't going to get you any love. ANY amplifier that does what it is supposed to will be more than fine, but again the more power the better.

Take one of those sets of components and sell them, it will definitely help your SQ and staging more than any amplifier will.

[Lucky 76 5]

Ya. You only need one set of components. Whether it be one set in the back and one set in the front or 2 sets in the front. Just scrap the rears because they don't do anything and/or scrap your second set up front. They don't make the music louder either.

[Kanaworm$ 292]

Out of the 3 amps listed I know the Sundown the best. Not taking away anything from the other 2.

Take a look at the crossover and ssf filter on the Sundown. The Sundown has more flexiability, subsonic filter is variable, choice of either 12db or 24db octave slopes on the crossover frequency and a x10 selectable range switch. Also independent crossovers for channels 1-2 and 3-4 for running active if you chose to.

The 100.4 is more like 125 watts x4 if not a little more.

And if your worried about resale.....Sundown has a great rep online!

[Adrian_D 520]

Well don't tell that to members of other forums.

I swear reading some posts on one forum especially, had me wanting to drop big money on an Audison, Arc, and McIntosh. They are so warm and bla bla bla....next best thing to pussy.

One quick check of my checking balance brought me back to reality.

Warm and soft...good thing they are not brown.

Most of the differences are beucase of pshyco-acoustics. It's a very powerful thing.

Damned, there is an amp in Europe woth considering along with the Sundowns. The Nakamichi PA series, PA4100 and PA2100. Nicely built amps.

IMO, before you start changing gear, improve the install, like sealing and deadening the doors.

[Dammed 12]

The rear set is only being used when there are people in the back seats, which is almost never. It's kinda good to hear some music when you're in the back seats as well.

IMO you shouldn't assume that someone is starting from scrap if they don't write all of what they have done. My car is deadened pretty good (doors and floors), the trunk and the roof needs deadening but that's getting done before the install of the new subs and amps. The electricity is going to be good, a 180A alternator from Iraggi is going to be ordered soon, my car has a HC600 in the front and two HC1800 in the back, the big 3 are done and there are 1/0 cable for positive and negative going from the front to the back.

Nakamichi PA4100 doesn't have crossovers for ch1+2 and ch 3+4. I got this info from a forum, since I can't got hold on a owners manual and the website is just full of shit. Sorry, but all the fancy words are good and all, but how about some pictures of the terminals or some technical info?

All of them have independent crossovers for channels 1-2 and 3-4.

Soundstream has a variable subsonic filter as well, it's the Hawkin Boost Control, which also can give a 0-10db boost at the given frequency. The Rockford does not.

Since I didn't know much about the octave slopes, I googled a bit and found many sites and one really good one with some info on this: LINK

Loudspeaker crossovers also have filters. 12 dB/octave and 18 dB/octave slopes are commonly used to separate bands of frequencies between woofer, mid-range and tweeter. The steeper 24 dB/octave slope is usually only found in PA systems where an active crossover (for which a 24 dB/octave filter is easier to implement) divides the frequency bands before the signals pass through to the power amplifiers.

As I understand it, a 12db/octave slope will give a smoother sound in comparison to a 24dv/octave slope which will allmost creat a edge to the sound. Isn't 24 db/octave more useful in LPF for subs? I'm a novice in this field, but from what I have gathered by googling around a bit using a 24db/octave slope for mids/tweeters will not be really good. The sound will be unnatural and unrealistic. Am I mistaken here?

Edited January 2, 2010 by Dammed

[Impious 1,476]

Since I didn't know much about the octave slopes, I googled a bit and found many sites and one really good one with some info on this: LINK

Loudspeaker crossovers also have filters. 12 dB/octave and 18 dB/octave slopes are commonly used to separate bands of frequencies between woofer, mid-range and tweeter. The steeper 24 dB/octave slope is usually only found in PA systems where an active crossover (for which a 24 dB/octave filter is easier to implement) divides the frequency bands before the signals pass through to the power amplifiers.

As I understand it, a 12db/octave slope will give a smoother sound in comparison to a 24dv/octave slope which will allmost creat a edge to the sound. Isn't 24 db/octave more useful in LPF for subs? I'm a novice in this field, but from what I have gathered by googling around a bit using a 24db/octave slope for mids/tweeters will not be really good. The sound will be unnatural and unrealistic. Am I mistaken here?

I wouldn't agree with that link. For whatever reason, they are trying to describe crossover filters in subjective terms which is pretty ridiculous considering the resultant sound is going to be determined by much more than simply the crossover slope, and the necessary slope is determined by much more than a subjective "target sound".

24db/oct filters are perfectly fine and commonly used. My processor allows slopes up to 30db/oct, and I've used them to highpass my midbass because it allowed to me run a slightly lower crossover frequency while still keeping excursion under control and not killing the driver's power handling.

My advise would be to generally ignore that link's "description" of crossover filters. Achieving good sound is the ultimate goal, how you get there is less important.

[Dammed 12]

ok, man wish I had the time to buy a book on this stuff and read it. :S

I managed to skip something in my previous post, whats "x10 selectable range switch"? It's a x10 boost to the frequency span the crossover right?

How important, SQ wise, is the ability to change the slope from 12db/octave to 24db/octave when compared to additional 30W rms?

[///M5 2,833]

One thing perhaps hasn't been pointed out strongly enough. You ask about SQ, but then ask about crossovers on amps. IMO if you are truly going that route, NO amplifiers are flexible enough to use their crossovers and instead you should be using a processor.

I will also say that pre-choosing your crossover points, slopes, and phase before connecting your drivers is silly. Listening to what sounds best is the right method and that takes hours of comparisons. I use different slopes in every installation and with them come different crossover points.

[jcarter1885 995]

One thing perhaps hasn't been pointed out strongly enough. You ask about SQ, but then ask about crossovers on amps. IMO if you are truly going that route, NO amplifiers are flexible enough to use their crossovers and instead you should be using a processor.

I will also say that pre-choosing your crossover points, slopes, and phase before connecting your drivers is silly. Listening to what sounds best is the right method and that takes hours of comparisons. I use different slopes in every installation and with them come different crossover points.

Yes couldnt of been said better, Im still tweaking and adjusting my amp for my active lifestyle. I had preset frequencies to have them ran at and they were changed within that first day of listening and are still changing.

First we need to determine the installation methods and then driver choices and go from there. Amps will be the last thing to worry about especially if your an SQ head. Now if you want to have a good sounding system then that is different from having an SQ system.

[Dammed 12]

Yeah it's a good sounding system I am after. And my choice came down to the Soundstream amp, cause I believe the more power justifies the loss of being able to choose 12 or 24db/octave slope on the crossover. And like you two said, a external processor would do a better job either way, so when I'm going to go with a active set up, I might as well buy a external processor. For my passive set up, I think the Soundstream will be more then good enough.

So thx for the help guys.

[///M5 2,833]

If you are using the amp for a crossover even temporarily I'd REALLY want as many slope choices as possible.

[Dammed 12]

Yeah I though you would say that. But in the end with a external processor, I will get more from the Soundstream amp then from the Sundown Audio amp. Considering I will be running 2 sets of infinity Kappa perfect 6.1 passively on the amplifier I don't think it will mater much. I'll rather have a little bit less SQ in my system now, so that I might have great SQ with more power later on.

[///M5 2,833]

If you are running passive then you won't use the crossovers anyway...

[Dammed 12]

I'll maybe use the the LPS. If I use a external processor later, I won't use the crossover anyway. So the question comes down to build quality and power. And nobody has screamed SmokeStream yet and I haven't found any complaints about the amp on this or other forums. So It should be good. If the amp suck you all will hear about it here.