REVIEW: Surprised by SQ of Class-D Full Range amps!! Alpine PDX, JL Audio, Etc

[Papermaker85 5,000+ posts]

I wasn't taking a shot at you btw Bobby...

 

[cleansoundzz 10+ year member]

Hi Guys,
I had a chance to make it to a few local car audio shops and test some new equipment. Just thought I would give my 2 cents.

I generally ONLY like Class A/B amps for Midrange through Tweeter applications (Anything over ~80hz)

I decided to try the following amps:

Alpine PDX5

JL Audio HD9005, and HD7005

JL Audio 300/4v2 (Class A/B)

Rockford Fosgate Power T600-4

Speakers: Focal 165-KRX2 2-way components ($1200)

Head Unit: Kenwood DNX7180

I also tried misc JBL, Alpine, and any other speakers they had on display at the time (mostly models below $300). All 3 Focal models above $600 sounded similar other than "clarity". No noticeable cutoff or losses in frequency bands, just the $1200 set sounded more "clear"/accurate.

First impressions: All of the Class D amps have no audible noise/hiss when not playing material. Both the Rockford and the JL class A/B amps had audible hiss or noise when not playing material.

The Rockford T600-4 had perceptually more "punch" and loudness, BUT was not more clear and did not have the same full range sound as the other amps. First impression would say its "louder", though it was not gain matched to the other amps so appreciable volume is due to RMS/gain differences.

After 2 hours of listening to various types of music on HD Radio and CD, I determined the Alpine PDX5 and JBL HD9005 "sound" almost exactly the same. Level matched, I would say they would have the same equivalent perceived volume/loudness. Honestly, the only way I could tell which amp was playing was by looking at it. Sound difference was almost not determinable.

Bad camera pics of the demo wall at Car Toys:

Just thought I would post my findings! Let me know if anyone has any similar experiences or reviews!

Edit: Forgot to say, all of the Class D amps had 4 Gauge power connections. The salesman was telling me their installers only use 4 gauge with these amps and have no power demand issues (according to him).

-=Bobby //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

The RF T600-4 doesn't have a lot of midbass and is very thin sounding. I used the T400-4 over 4 different occasions and finally got it this last time. That's where the lack of full-range sound comes from on that amp. I heard the JL Audio HD600/4 last year over a variety of different songs and walked away very impressed to say the least. The sound really caught me off guard.

 

[VWBobby 10+ year member]

Papermaker, its all good. Its hard to tell on the internet what people really mean, unless they spell it out. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

It could be noise coming from the A/B display box that all the Car Toys type places have..... Anything is possible. The noise was only noticeable on both the Rockford and JL Class A/B amps....Make/Model did not seem to be dependent. It was reminiscent of the hiss/hum I get when I turn on my guitar equipment. Not noticeable while material is playing, only when no source is turned on or no source material.

CleanSoundz, That's a good way to describe what I experienced also. The T600-4 had a more thin sound to it in the mid-bass - high, but did sound "loud", but not as clean as the JL HD or the Alpine PDX....maybe boosted high range?

 

[cleansoundzz 10+ year member]

2007-2011 RF Power series amps are known for their boosted high range frequencies. This is mainly for the 2 and 4 channel amps. JL Audio is a proven product. I used the JL Audio 500/1 and 300.4 in my truck for 5+ years. Great amps but I am sure that their HD amps are now a notch above.

 

[cleansoundzz 10+ year member]

VW Bobby, the way you listened to different amplifiers before deciding to purchase them is the way selecting car audio should be done. With the options of programming different amplifiers to the same speakers gives the potential customer which sound is more preferable to him or her. Car audio shops with those options are a lost art because they are all closing down because lots of people buy their stuff over the internet. In the 90's there were many car audio shops open that allowed people to do this. Last year I spent about 2 hours listening to a range of different separates for my 4-Runner before making a purchase. I haven't even thought about changing them since I love the sound so much.

 

[cleansoundzz 10+ year member]

Gunz4Me, you hit the nail on the head. These amps are TINY (for their output) and super efficient. Even after playing for a couple hours at moderate volume, they were barely warm, if at all. I was very impressed. I used to be a die hard 90's SoundStream/PPI/Rockford guy, but these things have got me thinking twice.

Me too

 

[gunz4me2 10+ year member]

VW Bobby, the way you listened to different amplifiers before deciding to purchase them is the way selecting car audio should be done. With the options of programming different amplifiers to the same speakers gives the potential customer which sound is more preferable to him or her. Car audio shops with those options are a lost art because they are all closing down because lots of people buy their stuff over the internet. In the 90's there were many car audio shops open that allowed people to do this. Last year I spent about 2 hours listening to a range of different separates for my 4-Runner before making a purchase. I haven't even thought about changing them since I love the sound so much.

I remember in 97 or 98 when I was changing subs in my 1996 Ford Thunderbird. I drove out to the shop, told them I was thinking about swapping out my pair of 10" Savard Hi-Qs for something else that took up less trunk space. They had me pull my car in the install bay, then tried different subwoofers with my setup until I ended up with a 12" Solobaric. I miss those days of being able to trial and error gear at the custom shops. These days, I trial and error gear myself, lol.

 

[VWBobby 10+ year member]

VW Bobby, the way you listened to different amplifiers before deciding to purchase them is the way selecting car audio should be done. ....

In the 90's there were many car audio shops open that allowed people to do this. Last year I spent about 2 hours listening to a range of different separates for my 4-Runner before making a purchase. I haven't even thought about changing them since I love the sound so much.

Exactly. I got started in car audio when I was 15 years old. It was all the rage of the 90's to have your two 12's and a 500-watt amp. //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif I spent many hours at Stereo King, Car Stereo City, Car Toys, etc, etc back then. I can't count how much money I spent. This is the reason people need to support their local business. Its always nice to be able to buy a fuse, wire, or some other little part on a Friday/Saturday and not have to wait for shipping. Sure, it might cost a little more but you're helping someone support their family.

There is nothing like being able to test 4 or more amps in A/B situation. I think if 80% of the people on this forum went to a local shop and A/B'd some equipment, they would be surprised by what they heard. I know I never stop learning/hearing. Of course, some people could spend the time to build their own a/b boxes.

 

[cleansoundzz 10+ year member]

Trial and error in car audio is very very very very costly. This is why we have the forums and people ask the same old question "Is x brand better than y brand for bass, mids, highs, etc. If these people stopped trying to find the best underground brand and went to car audio shops and tried out different options then they would save lots of money and gain knowledge in the process. This was how I picked my Digital Designs amps. I went to an authorized dealer for digital designs, got to know him, talked to him about the amps, held one in my hand and listened to them, thought about it for a day then went back and purchased them. This is how I will do it from now on. The same way that you did it.

 

[Florida Rep 10+ year member]

Nailed it.
I have Arc Audio KS-mini and XDi amps in stock here at the shop.

I dare you to listen to them and hear a notable difference compared to similarly priced a/b amps.

Edit:

And the XDi-803 is a SICK amp for the average joe looking for nice sound on some comps and a small sub.

80x2 @ 4ohm for mid/hi

400x1 @ 2ohm for sub

I'm chomping at the bit to get a customer in an ARC 6.5" comp set and Sundown SA-12 or 2 ARC KS12 up and running //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Arc Audio makes one the the BEST SQ amps ever!! Don't believe me, look at the results of the past Spring Break Nationals & see how many of them were running Arc that won....umm more than ANY other amplifier company!! Arc Audio Amps = SQ

 

[PPI_GUY 10+ year member]

Have a listen to the JL XD series amps. Excellent SQ in a small yet powerful footprint.

 

[dtbrown 10+ year member]

I've recently installed a Alpine PDXF-6 replacing an older precision power class a/b 100x4 on Digital Designs DDA components running active. My overall decision to go with the Alpine was reviews, size and power. Once tweaking the x-over the sound quality and power difference was very apparent in the Alpine. Extremely impressed for the money and have really nothing bad to say.

Also recently installed the imprint and once tuned with the MIC what a difference. I'm still playing with the positioning but the initial tuning of whole car center the fullness of the my system is nothing like I've heard in most cars. I'm still tweaking for driver position but so far very happy with investment in Alpine pdx-f6 and imprint.

 

[icehellion 10+ year member]

Im actually looking at the Alpine PDX F6 to run a set of Boston SPZ60's, however Im prepared to go with a Boston GT 2300. So everyone, whats the final word on this issue? Is there a poll? I havent been able to find one.

 

[Bettr n' Revrse 5,000+ posts]

All is true now someone buy my PDX 4.100!

 

[cleansoundzz 10+ year member]

That's why I eventually settled on a Alpine PDX M-12 and F-4 for my truck. There is no noise or hiss in my system now.