valladon

Well beyond the decimal place, your tens place is also inaccurate and by a crapton. Your "point" of testing is no more accurate than having two amps and listening to them an hour a part and picking a power level for each. For all I know your idea of "usable" is 30% distortion, hell if it is on a sub I would suspect that there are more people with their subs near 30% than near 0.07% in this world. By a landslide. As an aside, you also left frequency out of the equation. Do yourself a favor, grab anyone you don't know off a forum that lives near you and have them do the exact test you did. If it is truly a blind test the results won't even be within 25% of your numbers. Subjective or scientific. You can't have both and you chose subjective. Just don't put a number by it as it tells the internet nothing. If you want to do scientific then by all means I would love to go out of my way to support your site. The internet could use a site like that, but beware as we are just barely touching the surface of what is truly required to make it repeatable AND real. frequency was a 50hz test tone. I thought I put that in there.

You can take the for sale thread out. I have them sold a couple of times over, but I think I might hang on to them and do some more testing.

I have an Arc Audio 4050XXK and 2050XXK. Both are in excellent shape, but don’t have the original terminal screws. These amps put out more than rated power. Check out my review of them on www.n2caraudio.com Looking for $240 for both plus shipping. My zip code is 96003. Arc Audio 4050XXK Stereo @ 4 ohms: 4 x 50 watts Stero @ 2 ohms: 4 x 90 watts Bridged @ 4 ohms: 2 x 180 watts THD %: <.07% Freq Response: 20 Hx - 20 KHz Signal to Noise Ratio: 95db Seperation: >65db Transient Dist.: <.01 Input Sensitivity: 250 mv - 2.5 v Bass Boost +18 db @ 45Hz Crossover (Butterworth): 55Hz – 5.5kHz 12db stereo Max Current Draw: 46 amps Damping Factor: >300 @ 1Khz Dimensions: 13 x 8 x 3.35 Specs: Arc Audio 2050XXK Stereo @ 4 ohms: 2 x 50 watts Stero @ 2 ohms: 2 x 95 watts Bridged @ 4 ohms: 1 x 190 watts THD %: <.05% Freq Response: 20 Hx - 20 KHz Signal to Noise Ratio: 100db Seperation: >75db Transient Dist.: <.01 Input Sensitivity: 250 mv - 2.5 v Bass Boost +18 db @ 45Hz Crossover (Butterworth): 55Hz – 5.5kHz 12db stereo Max Current Draw: 28 amps Damping Factor: >300 @ 1Khz Dimensions: 8.75 x 8 x 3.35

Sean is exactly correct with his comments in that thread. "Power testing" is useless if not conducted in the proper manor with the proper tools. Same reason I loathe people performing or discussing "clamp tests". Sure, you got some #'s to put in your review and on your site, but what is their usefulness or reliability? Pretty much zero. And FYI, there isn't much of anything "real world" about that test. Please don't use that as a defense. A properly conducted set of scientific measurements represent the "real world" far better and much more accurately than any random and improperly conducted test, and the information gained from the scientific testing is much more useful and relevant than in the latter. People have this ignorance based confusion that there is some large disconnect between "scientific" and "real world", and then try to use the "But I'm testing it in the real world" defense. That's utter nonsense. Interested in what you used for a consistent load as well as how you measured the current and distortion. I wonder if I should repost our discussion from the for sale thread? Sean is exactly correct with his comments in that thread. "Power testing" is useless if not conducted in the proper manor with the proper tools. Same reason I loathe people performing or discussing "clamp tests". Sure, you got some #'s to put in your review and on your site, but what is their usefulness or reliability? Pretty much zero. And FYI, there isn't much of anything "real world" about that test. Please don't use that as a defense. A properly conducted set of scientific measurements represent the "real world" far better and much more accurately than any random and improperly conducted test, and the information gained from the scientific testing is much more useful and relevant than in the latter. People have this ignorance based confusion that there is some large disconnect between "scientific" and "real world", and then try to use the "But I'm testing it in the real world" defense. That's utter nonsense. So what if I did the tests both with a distortion analyzer in to a 4 ohm dummy load and then showed those results vs what I call "real world" would that make more sense?

Interested in what you used for a consistent load as well as how you measured the current and distortion. I wonder if I should repost our discussion from the for sale thread? Could move it or merge the threads if you like. I posted this here a day before responding in your for sale thread. Yea, lets merge them. This is a good discussion, and I think others would benefit from it.

That was the point of my testing, a .07 thd means very little to the human ear. I wanted to see what the amplifier was putting out in true usable power. I do agree with you on two point though. One I need to take the turn "putting out more that rated power" cause that implies that the numbers are at the same distortion % and s/n ratio as what the manufacturer stated. Two, the power numbers are not accurate enough to add a decimal place. LOL.

Interested in what you used for a consistent load as well as how you measured the current and distortion. I wonder if I should repost our discussion from the for sale thread?

Just finished some power testing on the Arc Audio amps that I did a review of, there posting on my site n2caraudio.com. If anyone is interested. LOL

Your tests are bogus. Great amps, but that statement is not backed up by ANY science. wattage = voltage squared divided by resistance. where is the error there? Its ohms law, not mine. Science requires more than an equation but a methodology that is repeatable, reproducible, and accurate. From all I can tell you didn't use a calibrated load, you didn't measure distortion (so therefore the value you measured is arbitrary), and you probably don't even have an accurate way of measuring either voltage or current. For sure, it isn't accurate enough to report the digits you reported. So indeed, there is absolutely no science behind your statement. Not knocking the amps, nor did this have to happen in your for sale thread but you failed to respond in your review thread so I have no choice. Sure looks like your review was just a mechanism to sell your amps by inflating their worth by misrepresenting their power. Really not necessary since they are great amps. I do appreciate the criticism, but I did list the parameters in which I took the measurements. I decided not to use a dummy load, because I wanted to see what real world power was coming out of these amps so I used a reactive load (subwoofer) with a electricial DC of 3.5 ohms at rest. Its true I didnt use a distortion analyzer (I mentioned this in the review) I took measurement by driving the speaker to distortion and backing it off till their was no audible distortion. (also what I believe to be "real world" testing) I do like your idea of driving up the value of the amps though. And if I werent selling them cheaper here then I could get for them on ebay, I would say that thats true. But my real motivation in all this is to buy and sell equipment quickly so I can do more reivews. And hopefully drive more people to my website. I would have responded to you in the review thead, but I forgot to subscribe to it and didnt see you reply till you mentioned it. But I have no problem with you bringing it up here in the sale thread.

I must have got this pics mixed up. I will fix it later today. It's ok, just messing with you. GLWS. thanks denim

Your tests are bogus. Great amps, but that statement is not backed up by ANY science. wattage = voltage squared divided by resistance. where is the error there? Its ohms law, not mine.

I must have got this pics mixed up. I will fix it later today.

I didnt include the brand of the reference amplifer cause I didnt want it to be a this vs that review. But the amp I am using as a reference is the Rockford Fosgate T3002

First impression: The Arc Audio 4050XXK and 2050XXK are quite beautiful amplifiers, although the pictures cannot pick it up. The heatsink fins are machined aluminum, but they have an almost chrome shine to them. The amps have a nice solid feel with the exception of the bottom plate, which is an access panel to the internal workings of the amplifier. As far as the connectors go, the rca inputs are very high quality and have a nice solid feel to them when plugging in male rca connectors. I was surprised to see screw terminals on such a well built amplifier. They work ok for a lower power amp like this, but I would only hope that the larger XXK amplifiers would have either larger screws for power, or the straight wire connectors like most modern amplifiers come with. Specs: Arc Audio 2050XXK Stereo @ 4 ohms: 2 x 50 watts Stero @ 2 ohms: 2 x 95 watts Bridged @ 4 ohms: 1 x 190 watts THD %: <.05% Freq Response: 20 Hx - 20 KHz Signal to Noise Ratio: 100db Seperation: >75db Transient Dist.: <.01 Input Sensitivity: 250 mv - 2.5 v Bass Boost +18 db @ 45Hz Crossover (Butterworth): 55Hz – 5.5kHz 12db stereo Max Current Draw: 28 amps Damping Factor: >300 @ 1Khz Dimensions: 8.75 x 8 x 3.35 Arc Audio 4050XXK Stereo @ 4 ohms: 4 x 50 watts Stero @ 2 ohms: 4 x 90 watts Bridged @ 4 ohms: 2 x 180 watts THD %: <.07% Freq Response: 20 Hx - 20 KHz Signal to Noise Ratio: 95db Seperation: >65db Transient Dist.: <.01 Input Sensitivity: 250 mv - 2.5 v Bass Boost +18 db @ 45Hz Crossover (Butterworth): 55Hz – 5.5kHz 12db stereo Max Current Draw: 46 amps Damping Factor: >300 @ 1Khz Dimensions: 13 x 8 x 3.35 For the first test I hooked up the Arc 4050XXK to the front 6.5” MBQuart Components, and the rear MBQuart 6x8’s. The 2050XXK was hooked up to the 12 Fi sub bridged at 4 ohms. Once this was done, I started adjusting the settings on the amplifiers. Even from the back of the vehicle with only the radio on, I could pick out instruments and sounds in the music that had not been as pronounced in the reference amplifier. Once all the gains and crossover points were set, I put all equializtion at 0db and turned the bass boost on each amp to the 0 position. I put in some familiar cds just to see if I could pick out things that I hadn't heard since my Zapco amplifiers. I immediatley noticed that some of the reverb from the vocals were more pronounced and natural sounding. Things like the snapping of fingers and the breathing in between vocals all became pronounced and audible. The tamborines, which are heard in the background became more a part of the music. Both amps played with very good power and authority for being only 50 watts per channel. Once pushed beyond their capabilities, I noticed an immeditate drop in sound quality, so it is very easy to know when you're exceeding the limits of the amplifiers. For the next test I hooked up the 4050XXK and left out the 2050XXK. I wanted to see how flexible this amplifier really is. I drove the four door speakers at 2 ohms, with the front outputs and the sub bridged off the rear outputs at 4 ohms. This test was very predictable, but I wanted to prove it to myself anyway. The sub had no change in output or clarity between the 2050XXK and using the rear out of the 4050XXK. The four door speakers sounded every bit as good as they did when at 4 ohms, however couldn't get quite as loud as before without becoming audibly edgy. Conclusion: The Arc is quite powerful and seems to put out more than what the rated power says. The power coming from this amplifier would probably satisfy most daily drivers, and no doubt would make even the most critcal ear happy. However, if you're looking for amp that you really want to crank up, I would suggest the next more powerful xxk. Bruce n2caraudio.com

http://cgi.ebay.com/ADIRE-AUDIO-website-trademark-www-adireaudio-com-/220648129625?pt=Domain_Names&hash=item335fa74459

First off, I bought this amp cause I just wanted to see if it really lived up to the power ratings that I saw on birthsheets and on the rated vs actual power site. I got it used for $90 shipped. (Got a great deal on it) My first impression of this amp when I took it out of the box was, wow its almost as big as my T10001bd, very heavy and solid. I hooked it up to a pair of 10's in my F150. I have had several amps in my truck JL audio, planet audio, Zapco, and a couple other I can remember off hand. Going through my music ranging from hard rock to rap, this amp blew me away. It has close to the SQ of the Zapco (probably cause its an ab class and not d class like the other amps I have had on the subs) and the power output of the Planet audio bb1350.1. It stays cool even in the 115 degree heat here in Nor Cal, and hasn't shut down yet even when pushed hard. The one negative is that like my T10001bd the cover rattles with the bass notes. But thanks to some guys here on the forum, I have gotten some tips on how to fix that. It does draw a bit of power, but that is to be expected for ab class amp putting out close to 900 watts. (according to the rockford website) For an amp that is rated at 50 watts per channel, this is an incredible value. I will re-review this amp in a couple of weeks cause I want to hear how it sounds on my mids and highs. But as for sub duty, this is a definite thumbs up. rated power: 50 watts x 2 @ 4 ohms 150 watts x 2 @ 1 ohm 300 watts x1 @ 2 ohms average actual power: 223 watts x 2 @ 4 ohms 346 watts x 2 @ 1 ohm 838 watts x 1 @ 2 ohms http://www.rockfordfosgate.com/products/amp_power_output.asp

Its suppose to. That was a byproduct of the engineering on that amp. That it put out about the same wattage @ 2 ohms as it does at 1 ohm

The 703 watts is the bridged 2 ohm rating.

thats a tough one. But I know that some of RE Audio components are 2 ohm.

best amp I found for that kind of money is the RF t3002. I got mine for 90 shipped (used), puts out over 800 watts bridged into a 2 ohms load. VERRRRRY Underrated.

Good Job.

dewd, im not a newdie, didn't you read the first post? Then you should know that your question is just a little too vauge. Both are great amps with high effieciency. But they each have different power levels. Both will require an electrical upgrade and need to know how much power your subs will handle. The one thing that seems to set sundown apart is the great customer service, I have seen this first hand, Jacob is on the forums and answering any and all questions.

what impedance? How many subs? Whats your electrical set up? Whats the power handling on the subs? How much money you looking to spend? Whats more important to you SQ or SPL? Which looks better to you? how much room in you install do you have? Answer all those questions and I will be able to tell exactly which amp you should buy.

throwing random tweets everywhere improves imaging. I guess you guys didnt see that he asked a question about the tweeter manufacturer not if he should buy an extra set of tweets. No first hand experience, but I have heard those tweeters are pretty good. I do know that when clif designs first came out. I got to audition a few of there components and they were awesome. they seem to have cheapened up over the years, but I am basing that on the amps that they have come out with.

Can he do art work for the t series amps. Rockford fosgate that is.