# Alpine PDX-5 or JL Audio HD900/5?



## schtebie (Oct 5, 2009)

Hi there,

I'm a total car audio newb and have come to ask for help.

I've been trying to decide between the Alpine PDX-5 and JL Audio HD900/5 to power my speakers and subwoofer. 

My biggest confusion is with the subwoofer. According to the subwoofer's specs, it'll accept 200W RMS and 400W max. Would the HD900/5 be too powerful for the sub since it's rated @ 500W rms? I've been doing searching trying to figure out whether I would be blow the subwoofer by overpowering it, but haven't really gotten a definitive answer. 

Any help would be greatly appreciated!


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## BlueAc (May 19, 2007)

Just turn the gains down...


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## fiberglasslvr (Oct 4, 2009)

I would go wiyh the JL audio 900/5, not that the alpine pdx's are not good but the JL's are alot more efficient. as far as your subwoofer goes, as long as you adjust your gains properley you should be just fine.
good luck


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## schtebie (Oct 5, 2009)

fiberglasslvr said:


> I would go wiyh the JL audio 900/5, not that the alpine pdx's are not good but the JL's are alot more efficient. as far as your subwoofer goes, as long as you adjust your gains properley you should be just fine.
> good luck


Perfect! Simple explanation. Thank you so much.


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## Qicker306 (Oct 2, 2009)

The JL HD900/5 is better in pretty much every single way over the Alpine PDX-5. The HD is one of the most efficient amps out there, making for less strain on your electrical system and more power output to your speakers and sub or subs, also one of the smallest amps. I don't know what Alpine was thinking when they only made the sub output 300W, 100W per speaker but only 300W to the sub. Who is gonna run Type-X components and then a Type-S sub? Sorry for the rant but the PDX-5 has been a disappointment IMO. The HD900/5 is superior in all facets, I've seen two highend JL installs where the HD900/5 was the one and only amp in the vehicle. All in all, go with the JL, if ever you were to upgrade, the amo would still have plenty of power to dish out.


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## diamondjoequimby (Jun 30, 2009)

Qicker306 said:


> The JL HD900/5 is better in pretty much every single way over the Alpine PDX-5. The HD is one of the most efficient amps out there, making for less strain on your electrical system and more power output to your speakers and sub or subs, also one of the smallest amps. I don't know what Alpine was thinking when they only made the sub output 300W, 100W per speaker but only 300W to the sub. Who is gonna run Type-X components and then a Type-S sub? Sorry for the rant but the PDX-5 has been a disappointment IMO. The HD900/5 is superior in all facets, I've seen two highend JL installs where the HD900/5 was the one and only amp in the vehicle. All in all, go with the JL, if ever you were to upgrade, the amo would still have plenty of power to dish out.


this


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## fiberglasslvr (Oct 4, 2009)

Agreed With Quiker306, And diamondjoequimby, 100%


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## TREETOP (Feb 11, 2009)

Add one more vote for the JL over the Alpine.


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## Subirex09 (Nov 20, 2009)

I picked up a PDX-5 a while back before I heard about the HD900/5.

I still have it wrapped up in the closet waiting for my install in the Rex.

Only thing I will say about the PDX-5 is that Alpine has it underrated at 300W. The birth sheet I have shows 414 for the sub channel which I thought was pretty cool. The other 4 channels are underrated as well but I can't remember by how much.

Not that JL doesn't do the same thing but I have never had experience with JL. Does anyone have a birth sheet of what the JL really puts out? Is it above the 500 rated watts by chance? I am asking seriously because I am going with a PG RSDC102 sub and if the JL is rated at 500 but really doing 600, it would probably be a better amp for my application.

This sub is crazy efficient so 400 would cut it just fine, but it would be nice to give it 600 if the JL can do that. I have spoken with a few people on Phoenix Phorum who are only giving their RSDC subs 250 to 300 watts and happy with it but I know I would feel better if I could come closer to the sub's RMS rating.

Thanks.


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## inoii (Nov 20, 2009)

id go with the jl i have bad experiences with the pdx series..


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## nineball (Jan 17, 2008)

i guess i am the odd man out. one car has a pdx 4.100 and 1.1000, the other has a pdx5. i have been very happy with both. as subirex90 said they are under rated but then again most decent amps are. my birthsheet says 125 x4 and 424 for the sub channel. it is running a set of spx-177r comps active up front and a pair of sundown e8 subs in the rear. very happy with the end results and it fits under the seat in my 83 911, an amazing feat in itself! (ya i know the jl is small too). 

i have been a fan of both jl and alpine (except for the headunits other than the 9887/7998) for many years and still run a pair of 10+ year old w0 subs in one car.


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## t3sn4f2 (Jan 3, 2007)

schtebie said:


> Hi there,
> 
> I'm a total car audio newb and have come to ask for help.
> 
> ...


You subs power rating depends greatly on the bass content of the music, the average power of that bass content (that bandwidth's _crest factor_). The size box you are using it in, how much you clip your sub amp, etc. ....... 

It's not that cut and dry.

Lowering your gains will not protect your speakers. You will still be able to over power them if you raise your sub level or your master volume past the position that you conservatively set your sub gain at. Only way to protect it _in that sense _would be it you set all adjustments that affect the sub to their max while playing a LOUD bass heavy track and then set you gains to the highest you want the sub to go. From that point forward you can only put less power into it when any adjustments are made.


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## pstar2002 (Jan 12, 2009)

The JL, the alpine doesnt even compare IMO


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## neomsport (Nov 25, 2009)

I have heard that the sub portion of the Alpine (rated at 300w at 13v) is 
actually pretty 'weak.' On the otherhand, the JL HD will have at least 50 - 60% more
horsepower for the subs (but it is clearly not a real cheap solution). 

I was looking at the JL too, but opted for the Zed Leviathan, which is 150 x 4 HP, plus 600 RMS (at 4 ohms mono / all at 12.5V) for the sub(s). In my case, that is perfect for a pair of 8's in a small BP box. At $600, hard to beat. I heard my friends system, and it rocks.

So I ordered mine and it will arrive tomorrow! I can't wait to swap out my current 6 ch
(75 x 6) ads amp.

Here is a link to the new review, in case you did not see it yet.

audio gear reviews - Amplifier Review - ZED Audio Leviathan

Good luck,

Rick


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## ChristianM (Jun 15, 2009)

Subirex09 said:


> Not that JL doesn't do the same thing but I have never had experience with JL. Does anyone have a birth sheet of what the JL really puts out? Is it above the 500 rated watts by chance? I am asking seriously because I am going with a PG RSDC102 sub and if the JL is rated at 500 but really doing 600, it would probably be a better amp for my application.


As far as i know, JL doesnt provide a birthsheet with every amp, none of the 3 that i have owned has had one in the box, but i have been told that they gurante to atleast hit the RMS ratings


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## ChristianM (Jun 15, 2009)

oops i frogot, JL HD over the alpine PDX, love the HD line


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## basher8621 (Feb 21, 2009)

I have owned PDX amps and demo'd the JL amps. I say JL hands down.


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## ChrisB (Jul 3, 2008)

Another vote for the JL Audio HD series here. If my current equipment give me any issues, I will be either going for a 900/5 OR a 600/4 & 750/1.

As for the full range PDX... They just don't do it for me.


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## Jayvuu (Dec 11, 2007)

I think the pdx is fine for what it does, but I do agree that the sub channel is a bit weak. With all that said, I'm planning to get the 900/5 very soon. Lol


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## phildog33 (Aug 22, 2009)

id get the jl audio too


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## cobraa (Dec 4, 2009)

I also prefer JL audio then PDX


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## cuerx (Dec 6, 2009)

So, I can get the Alpine for $220 and it looks like the JL is at minimum $550.

Not wanting to blow the doors off my truck - just want a good sounding ride with a bit of punch.

Other than efficiency, why would you spend a $300 delta if you were me?

Thanks,

Patrick


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## ChrisB (Jul 3, 2008)

Well, if you like that lovely HISSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS sound, a super weak sub channel, and an extremely odd frequency response on the full range channels, then the Alpine PDX is just the amplifier for you.

If you want an amplifier that is quiet, has a decent sub channel, and has a fairly decent frequency reproduction plot on the full range channels, go for the JL Audio.

IMHO, it is NOT worth saving $300 to have an amplifier that actually sounds funny! Then again, you could wait for the new PDX series that is about to be released, if you have faith that they actually got it right this go round. On the other hand, I would prefer NOT to be Alpine's amplifier beta tester.


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## supirio (Dec 7, 2009)

Thanks for this post, I was about to get a PDX but sounds like I must get the JL...


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## ChrisB (Jul 3, 2008)

By all means, I highly recommend that you listen to both, preferably in a vehicle. Last year, while bored, I went to an audio shop and with my back turned to the sound board, I could pick out the PDX amplifier EVERY SINGLE TIME the sales associate switched over to it. I COULD NOT tell the difference between the JL Audio and the Arc Audio amplifiers on the soundboard as the sales associate was switching around. That was around the time when that shop was dropping Arc Audio due to lackluster sales in this town. It also sucks that Rockford Fosgate, Kicker, Memphis Car Audio, and JL Audio products seem to be what appeals to everyone around here. 

ETA: Mention names like Image Dynamics, Hertz, Focal, or Morel and the sales associates will give you that RCA Record dog stare. Even worse, I had one tell me that Sundown Audio was "Swap meet, flea market, type stuff." The ignorance runs deep in my local shops.


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## idrift4wd (Dec 10, 2009)

i think im going with the JL's too


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## minni (Dec 3, 2009)

convincing conversation I might consider the JL as well


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## meatpile (Dec 7, 2009)

cuerx said:


> So, I can get the Alpine for $220 and it looks like the JL is at minimum $550.
> 
> Not wanting to blow the doors off my truck - just want a good sounding ride with a bit of punch.
> 
> ...


Where'd you see the j/l for $550?

thanks


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## neomsport (Nov 25, 2009)

IF I needed a system amp for a micro space, I would not hesitate to buy the 900.5 over any PDX amp (or similar) but NOT anywhere near $900 plus. 
I am not really sure that 500 watts is enough power on the sub bass side, especially IF you don't have plenty of midbass to help compensate 
(running down to 50 Hz or whatever). I am kind of a midbass fiend I guess.

That's why I run 4 6.5" midbass (front and rear total 600 watts) plus the 600 mono on the subs. So that is over 1kW on the bottom, plus the 
150 x 2 for the front sats. It gets really loud for a single amp system.

I ordered my second Zed Leviathan today, for the other car, but will configure it as a normal F/R sat and single sub system 
(since that should be plenty for the wife).

Happy Holiday's!

Rick


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## Cooluser23 (Dec 23, 2009)

I was wondering how the Alpine PDX-5 compares to the JL Audio HD Series HD900/5.
Does having a weak-ish alternator make an impact on the decision?

The setup I'm considering:
This is for a medium - high end system in a very cramped car. (think Fiero, Miata, Boxter, Z3, Z4, etc..)

What I have planned so far:
5 1/4" components in the front (or 6 1/2") (I need to decide if I really want to cut that much on my dash)
4x6" plates in the back. (probably Polk Momo MMC 460, unless I find something better, or get the guts to cut a larger hole for bigger speakers)
and an 8" sub (if I can get the air volume an JL 8w7, otherwise a different one that can work with less air volume) (There really isn't room for a larger 10", or 12" speaker..


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## scoobysti87 (Dec 26, 2009)

this is great information seeing as how i was considering both of these amps as possible choices for piecing together my sound system, think i might end up going with the jl audio after all


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## subwoofery (Nov 9, 2008)

I'd wait for early next year to see what Alpine will release. New PDx Design from what I've gathered... 
I would choose v.2 over JL due to the price

Kelvin 

PS: please remember that the PDx v.1 is long outdated - the v.2 might improve on the possible flaws the v.1 had.


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## neomsport (Nov 25, 2009)

I would not wait for a product that may or may not be any better, but I can guarantee you it will be 'less expensive' for Alpine to buy,
since that is the motive and what nearly all brands pursue. 

IF your concerned re how efficient the amp is, due to your 12v system, the most efficient Class D amp I have seen is the Zed Leviathan.

audio gear reviews - Amplifier Review - ZED Audio Leviathan

This is super efficient, even better vs. other Class D types, and at 150 x 4, is signicantly more powerful vs. the PDX (2X) or the HD.
And it does it at 12V, which the PDX cannot. I really like the 600 plus watts on the subs, which is more then many monoblocks actually
do. I just got my second Leviathan (which will be installed this weekend), after reading an advanced copy of the new rave review in PAS,
which should be out in a week or so. I would check that out and then consider your options.

Cheers!

Rick


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## Cooluser23 (Dec 23, 2009)

Now that CES is here any news on the second gen PDX-5 series?


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## james2266 (Sep 24, 2009)

Ok, I figured I would tack this onto this thread rather than open up another thread. I have a PDX-5 currently in my car which is a couple weeks away from being upgraded. I can't wait for that. I am not overly happy with the sound. My question is can this thing be bridged to run 2 channels and the sub? I have seen a few places state that it can run 150 w rms bridged but when I look at the owner's manual on the Alpine website it doesn't say anything at all. It also doesn't seem to have any guidelines about how to do it directly on the amp connections. Also, all the sources I have seen state ratings only for 4 ohms. Is this stable at 2 ohms as I am running Kappa comps? Thanks to anyone that might have some insight. It isn't super important as I am about 2 weeks from the full upgrade. I can't wait to hear what that sounds like!


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## Cooluser23 (Dec 23, 2009)

Any new developments on this? Has anybody tried a 2nd gen PDX series yet?


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## jmontoya21 (Apr 8, 2010)

t3sn4f2 said:


> You subs power rating depends greatly on the bass content of the music, the average power of that bass content (that bandwidth's _crest factor_). The size box you are using it in, how much you clip your sub amp, etc. .......
> 
> It's not that cut and dry.
> 
> Lowering your gains will not protect your speakers. You will still be able to over power them if you raise your sub level or your master volume past the position that you conservatively set your sub gain at. Only way to protect it _in that sense _would be it you set all adjustments that affect the sub to their max while playing a LOUD bass heavy track and then set you gains to the highest you want the sub to go. From that point forward you can only put less power into it when any adjustments are made.


i second this,your amp gain is not a power control is there to regulate how much output from your head unit is needed to reach the desired output of the system, so if turn your amp gains way down you would have to run your head unit volume and sub gain high to get your system as load as you wanted for a particular song,ideally you want your components to clip at the same time,so you match both outputs as equal as possible,your amp will always putout whatever the max is, it the depends on the song and how loud you play your system,im not saying it wont work but you the chance of over powering your sub will always be there, especially with a clipped signal


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## evo9 (Jul 6, 2005)

I needed a small 5 channel for the wifes ride. I had the chance to listen to both. I took the JL HD. The alpina pdx was weak in every aspect of the sound reproduction.



.


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## neomsport (Nov 25, 2009)

evo9 said:


> I needed a small 5 channel for the wifes ride. I had the chance to listen to both. I took the JL HD. The alpina pdx was weak in every aspect of the sound reproduction.
> 
> 
> 
> .


Not surprised to hear your thoughts on the PDX, as it is pretty much the consensus I think. 
I wonder if the prior post from CB re being able to "pick out the PDX Every Time" was due to the fact
that it did NOT sound very good, as sometimes an overly bright kind of sound, ala Class B types IS NOT
hard to hear (so that distinction would be a reason to NOT pick that amp).

I don't think that 300w of unregulated power (so really more like 250 watts at 12V) is enough to drive
a decent sub(s) properly, certainly not to full X-max. I would bet that the new PDX still lack low-end
capability, and was only 'redesigned' to update and probably lower the cost, so Alpine can sell it for
less and/or make more money. Few audio products, esp these days, EVER get "improved" for the
consumers sake, with the exception of 'fixing' problems related to warranty issues or other problems.

I have yet to see a good review on the HD amps, but have read of more than a few guys who were rather
unhappy with sound of their HD amps, but then everyone has an opinion on how things 'sound.' No doubt
the HD's are superior to the PDX, _but they should be at those prices!_

I have now had my Zed Leviatans for a few months now, one in each car, and they continue to work like 
a charm. Having a real-world 500+ watts on the subs (@ 12V), plus the 600+ on the high-pass/midbass
is just perfect IMHO. That you can get this level of superior full-system performance for $600,
_is just a smokin' good deal as far as I am concerned._

Cheers!

Rick


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## ErinH (Feb 14, 2007)

^ there are plenty of guys giving good reviews on HDs

italynstallion has a 900/5
I have 600/4's and a 750/1 and like them both.


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## neomsport (Nov 25, 2009)

That's fine and certainly true, and no disrespect intended, but compared to what, a PDX
(or something worse)? It is also true that there are more than a few who are underwhelmed
with their HD's...

If the HD's are so wonderful, then I find it curious why has there not been some kind of
legitimate rave review on the 900.5? I suspect there IS a reason for this rather conspicuous 
absence.

Cheers!

Rick


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## jimbno1 (Apr 14, 2008)

Well I have not been able to hook mine up yet so I cannot provide a review. But here is something to consider about the HDs that may say more than a review can. How many do you see up for sale used? They are very rare. If so many people are disatisfied with the HDs then why aren't more up for sale.


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## ErinH (Feb 14, 2007)

I like my hd compared to let's set...
pdx, zapco dc, jl audio slash series, blaupunkt and a few misc amps.

there's probalby not been a 'legitimate' review because the people who own them aren't taking the time to write one.
it doesn't mean it sounds bad. 

you don't have to take my word for it. I'm just replying to your post. I like mine. So do the judges who've listened to it. So much for all Class D's sounding the same. 

Edit: ^ in other words, these class D's don't sound like junk. Maybe all the others don't either. 

Meh, this is useless.


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## DS-21 (Apr 16, 2005)

neomsport said:


> If the HD's are so wonderful, then I find it curious why has there not been some kind of legitimate rave review on the 900.5? I suspect there IS a reason for this rather conspicuous absence.


Perhaps because people who buy them tend more to the non-idiot side of the spectrum, and realize that sonically amps are all commodity parts. There's no point to "raving" about sonics when in fact that is simply not an area in which competently designed-and-made amps differ.

The Jello HD's (count me as a perfectly satisfied HD600/4 owner, who may just add another, or an HD900/5, to his system) just offer good power in an all-around small package with excellent build quality.


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## neomsport (Nov 25, 2009)

Whoa now boys. Glad you are all satisfied with your new stuff.

I never said anything about anything "sounding bad" (did I?) nor did I say, nor imply, that "all Class D's
sound the same," though it is true that most Class D sub amps all sound pretty similar, if only due to SQ
differences under 80 Hz are not easy to hear, and the enclosure and car _make a big difference in perceived SQ._

There are for sure a short-list of full-range Class D amps that have been tested and documented to have
top-drawer SQ, and Zed Leviathan is clearly on that list (click link if you have any doubts on this).

Performance Auto and Sound - The Girls - The Cars - The Life - ZED Audio - Leviathan

What I was referring to re "legitimate reviews" is not about some consumer, who is still on the honeymoon
with his new investment, but rather a credible, qualified amp expert who knows what a good amplifier 
sounds like, and how it measures on the bench (like Gary at PAS or R. Zeff). 
Otherwise it does not mean very much.

Numbers (objective data) and A/B listening/experience (subjective) are what makes a good review, 
just the same as in testing cars like the magazines do (CD, MT or Road & Track et all). 

What I was referring to is why JL has opted to NOT have the new amps run thur the ringer by PAS 
(who would likely give it a big 'thumbs up'). I find this rather curious.

Just my .02 cents. 

Rick


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## ErinH (Feb 14, 2007)

^ understood. 

as far as 'legitimate' reviews. Who knows. I benched mine. That's about all I can do. It gives rated power. 

FWIW, my issue with ALL pdx's isn't a lack of balls or whatever anyone says in regards to power. It's the crappy noise floor. Even on the bench, off a power supply with a dvd player sending it signal, powering a set of mildly sensitive midranges, gain all the way down, there was audible hiss through the speakers. 
All the PDX's I've owned exhibit this. Other than that, I'm fine with the PDX line. But, because of that, I'd suggest the JL hd900/5 if the budget permits. However, I've got a pdx-5 in my wife's car because I can't justify a $600+ amp in her car when a used pdx-5 goes for $250.


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## neomsport (Nov 25, 2009)

^ Understood and concur with your postiion on the other car system
budget (but I drive her car a lot too, and I am spoiled on SQ expectations).

But from my perspective, HIGH noise floor = low SN ratio, and in ANY
amp, that is V V V bad (hard to ignore). That kind of residual noise
is pretty much the hallmark (signature?) of most/typical Class D
amps. The cost to filter this totally or reduce it is simply not compatible
with a "small" amp or keeping the costs down to improve margins
vendor and brand. So back to my point that I doubt the new PDX
will be much, if any better.

Cheers!

Rick


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## neomsport (Nov 25, 2009)

By the way, just to insure that no one thinks that I have no basis for my thoughts
on this, here is some info (which I forgotten about), to support my premise, as it really
bothers me when people make totally unsubstantiated claims based on the same old
_ "I heard from..."_

JL Audio HD600-4 [audiojunkies]

The other people I have spoken with, who's opinion I totally respect, due to their
extensive experience, were also equally not impressed re SQ of this series, so
the above experience absolutely not a unique one. I think this sort of evidence 
is pretty compelling.

Cheers!

Rick


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## ErinH (Feb 14, 2007)

Mark Eldridge has no problem cleaning up in SQ comps and he's running only the HD series amps... 

SQL Points Standings


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## DS-21 (Apr 16, 2005)

neomsport said:


> were also equally not impressed re SQ of this series,


Amps don't have "SQ." Anyone talking about the "sound" of an amp, unless they're discussing something real backed by measurements, such as frequency response aberrations or a high noise floor, is simply deluding herself/himself.


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## neomsport (Nov 25, 2009)

Just as an FYI, as I recall, Mark Eldridge is the JL Audio rep for his state, so that _might_ have something to do with his amp choices. 
Not sure what he was running "last year" -- but I would bet it had something to do with his income...

As far as the "sound" of various amps goes, there are more then enough people who would easily argue the point, especially those
in the high-end home market, based on an array of things that cannot be measured, including subjective opinion of A/B type testing
against a sound-quality reference amplifier. No doubt that measurable issues with an amp, noise or signal response or whatever, do
support a way to document inferior sound, but _that is not the whole story._

As stated before, I am not saying any amp sounds "bad," but clearly a lot of people feel strongly that some amps DO in fact, 'sound better' 
Certainly there are some people who are just not impressed with the HD amp performance, to justify my original point, that it would 
appear there IS a reason that JL has apparently opted to not get a test/review done on the 900.5 HD. That's all.

Cheers!

Rick


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## DS-21 (Apr 16, 2005)

neomsport said:


> As far as the "sound" of various amps goes, there are more then enough people who would easily argue the point, especially those in the high-end home market,


People generally aren't very bright. There are "more than enough people" to argue any number of things with zero basis in reality. In 2003, didn't "more than enough people" argue that Iraq had WMD? Were those people right, or did the "facts on the ground" prove them to be mistaken?

The only reliable _data_ - results of level-matched blind subjective same/different listening comparisons - all say that "differences amp sound" between competently-designed amps is a marketing idea with no basis in reality. (Yes, there are some amps - mostly on the extreme high and low ends of the price scale - that have measurably and audibly flawed performance.)



neomsport said:


> including subjective opinion of A/B type testing against a sound-quality reference amplifier.


Any audible issues, whatever the cause, will be determinable by a properly conducted same/different listening comparison. (One should never assume differences without confirming them in a same/different listening comparison first.) Now, if the issues are inside a person's head ("any amp that's more expensive must sound better," "a small class-D amp must be sonically inferior," "an amp from brand x is bright but an amp from brand y has a liquid midrange and smooth treble," etc.) and can only be determined by _knowing what amp is actually playing,_ then no, a proper test will not take into account the effect of propaganda and pseudoscience on a listener's brain.



neomsport said:


> No doubt that measurable issues with an amp, noise or signal response or whatever, do support a way to document inferior sound, but _that is not the whole story._


You choose to believe in magic, witchcraft, and voodoo. I understand that taking an electrical signal and increasing its amplitude is an engineering exercise, and not a terribly complex one at that.


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## neomsport (Nov 25, 2009)

See, my friends, THIS is exactly how the typical BS on forums get ignited.

LOL! "Zero basis in reality," really, just really? How can you even suggest that there are NOT a LOT
of very intelligent people who are convinced there ARE sonic differences, be it small, re the sound of 
electronics? This IS a reality, regardless if YOU like it or not.

And FYI, your comparison and Iraq example are just plain absurd. 

_"You choose to believe in magic, witchcraft, and voodoo."_

Look pal, you are WAY over the line here making wild ass-umptions and personal accusations about me 
(and numerous other people), based on nothing more then a comment that "there are plenty of people" 
who would debate that their subjective experience in A/B comparisons are legitmate. To attempt to totally
dismiss this is laughable and arrogant.

Is it true that measurable things contribute to sound quality, of course it is. But it is equally true that 
amplifiers can be engineered to have super-low THD, but as a result (excessive feeback, for example), 
they simply do not sound as good as others with higher THD and or superior parts/better design. 
This is not some "urban myth," and if you disagree, then fine, but show some respect. However,
to try to denigrate and attack me over such innoculous (and true) statements, _is childish at best. _

_"There are many things in this world that are true, 
regardless if YOU believe in them or not...."_

Rick


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## jimbno1 (Apr 14, 2008)

Can you provide any published, ligitimate, independently verified, double blind A/B listening tests with amps operating without clipping that backs up your assertions above? 

Thanks,
Jim


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## mmiller (Mar 7, 2008)

basher8621 said:


> I have owned PDX amps and demo'd the JL amps. I say JL hands down.


Agreed..... there is zero comparison performance wise between the 2!!!!!


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## kyheng (Jan 31, 2007)

After watched a video from AES Workshop, I starting to think differently. There's alot of factors affect our decision when buying something. And most of the time, our brain will betray us. Might sound funny, but that's the fact we have to agree and accept sometimes. 1 of the biggest influence is our expectations. Just say there's a Pioneer Premier 4 channel that cost $250-300 but JL Audio HD600/4 cost $500-600. We should be expecting something(from the paper spec) to be better than Pioneer, right?


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## JDMRB1ODY (Oct 11, 2008)

The A/B amp VS D class amp wars totally makes sense when you consider the technology is fairly new and all the old school a/b folks don't want to change or feel threatened by the new design. I just feel the sound debate won't stop the market shift to class D due to all the advantages in smalled size and big power in a small package. There will always be a market for A/B but it will be much smaller. If class D amps were so bad why are alot of major players coming out with them. Look tube amps are still around after all these years. The JL HD vs Alpine PDX debate for me comes done to reliability which Alpine has had issues with.


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## neomsport (Nov 25, 2009)

I am very confident that there are such test reports, but I know from first hand experience, in a 'double-blind,' A/B test
of a Class B vs. Class A/B versions of the identical "competently engineered" amplifier, and I could tell the difference 
every single time (and this was not even on a decent high-res playback system). 

The difference, due to audible crossover-distortion, was very apparent, so that is good enough for me. If there was NOT 
a difference in that, then why would Class A/B amp even exist? FYI, a high percentage of the cheap, PRC made amps 
are actually Class B, since they have no use for labor-intensive "nonsense" (like properly biasing amp channels).

Q: _If class D amps were so bad why are alot of major players coming out with them._

(Again, I never said the recent, full-range Class D amps sound bad). I have a Zed Leviathan (actually 2), and they both 
sound fantastic, as do a few home audio amplifiers now highly regarded in the audiophile realm.

A: They cost A LOT less to make, since all your really building is a 'power-supply' that is adapted to reproduce audio. 
So NO "output section," traditionally speaking, thus the parts cost is lower, the packaging is smaller, and so the product 
is predictably both more efficient and most importantly, far less expensive.

I just really do not appreciate it when anyone tries to tell me what I do, or do not believe in. I really don't have the time or 
desire to debate this further as I have other things to do, like going to see Jeff Beck tonight 
at the Nokia Theater...
_So yes, I actually do know what real music sounds like._

Cheers!

Rick


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## kyheng (Jan 31, 2007)

^You may know what real music is, but does not means others same as you.....


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## jimbno1 (Apr 14, 2008)

Just as I suspected, no legitimate test results. 

I find it laughable that no one in the audiophile media does regular double blind a/b testing. It is so obvious they so not want to offend their advertisers. 

Here is a quote from Bob Carver, a man who knows a little about amplifier design.

Audio Ideas Guide Interviews: AIG Talks with Bob Carver

GB: How audible are the differences between solid-state amplifiers? 

BC: What I’m going to say will fly in the face of what most people believe. *I believe that you can take two solid-state amplifiers, and provided neither one is overloaded in any fashion, they’ll sound identical. *That’s a big if. Amplifiers are overloaded in three basic ways. They’re overloaded in amplitude; they’ve overloaded in current; they’re overloaded in speed. It’s very easy to do this if you don’t have a big juicy amplifier. Obviously a little Radio Shack amplifier is not going to be able to touch a big Jeff Rowland or a Mark Levinson or a Sunfire amplifier. Provided the amplifier has flat frequency response and sufficiently low distortion, both of which are trivial these days, and provided there are no interface problems, the differences will always be the subtle differences associated with overload, either momentarily, like slew-rate limiting or clipping, or just running out of drive current.


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## DS-21 (Apr 16, 2005)

neomsport said:


> LOL! "Zero basis in reality," really, just really? How can you even suggest that there are NOT a LOT of very intelligent people who are convinced there ARE sonic differences, be it small, re the sound of electronics? This IS a reality, regardless if YOU like it or not.


They may be intelligent in _other_ areas, but in this area they're just deluded. Or at the very best ignorant of the mass of peer reviewed scientific literature on audible differences in electronic components.



neomsport said:


> Is it true that measurable things contribute to sound quality, of course it is. But it is equally true that amplifiers can be engineered to have super-low THD, but as a result (excessive feeback, for example), they simply do not sound as good as others with higher THD and or superior parts/better design.





neomsport said:


> _"There are many things in this world that are true, regardless if YOU believe in them or not...."_


That is likely true. But some magic amp "sound" is not one of them.


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## ErinH (Feb 14, 2007)

awesome. this thread has turned into what I knew it would.

we have enough 'class d amps sound bad' threads.

neom, I suggest you listen to these yourself. I've had plenty of people sit in my car and not complain a lick about them being class D amps. 
As far as me trying to defend it, I see there's no point. You hear, read what you want to read (you=whoever). If you sell yourself on a characteristic without hearing it yourself then there's no point of trying to argue about the point. 

I'm out of this thread and it is now the typical 'amp sound' BS thread with no listening experience from the naysayer and no data to back it up. 

- Erin


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## neomsport (Nov 25, 2009)

For the forth and last time, I never said any amp sounded "bad." Clear? Only that there are a couple qualified people I know
and trust, who have told me they were underwhelmed with the sound of the HD amps, for whatever various reasons. This clearly
suggests that they have heard other amps that clearly 'sounded better.' I certainly do not have the time or desire to chase down 
examples to make my case any stronger. 

Therefore, by logical extension, it makes sense that NOT all amps sound the same. When there are stellar test-bench numbers 
(objective data) to back up the opinions that a given amp sounds "great," then that is a qualified review, IMHO. This is what 
prompted me to choose the Zed Audio Leviathan, which IS a great sounding amp, according to the two tests/reviews I have seen, 
and of couse my personal experience in swaping amps.

It does not really matter IF the reason is a high-noise floor (as mentioned re the PDX), or inferior/non-optimal PCB layout, or due 
to Class B design, or poor topology, or PRC cheap component design, or clipping induced by the power supply collaping
under load (typical scenario), the reality is that people will often choose to prefer the sound/performance of particular amplifier 
over another amp. _How and why anyone would argue this point escapes me._

Bottom line is all amps do NOT sound the same (in the real-world), no matter how you want to try to rationalize it or qualify it, 
per some 'theoritical,' perfect world, scenario. I mean, at the end of the day, there can be question or arguement that vendors 
make compromises on consumer products to cut costs and buy homogenous, off-the-shelf designs, specifically to insure 
everyone in the food-chain makes maximum profit, while keeping things as cheap as they can, to minimize the selling price 
(regardless if it is at the expense of the potential reliability of the product).

I have both a Sunfire amp, and while BC certainly has credentials to spare, but some of his solutions and specs are rather 
"curious." I absolutely perfer the sound of my SAE amp (both rated at 200w per ch), having done comparisons in the past. 
The Sunfire is now relegated to running my HT subs, center ch and rear speakers, and it sounds just fine.

If you doubt this wild theory, then this would make the benefits of Class A amps, which clearly exhibit lower measurable distortion, 
and tube "sound" amps as urban myths. Or alternatively, you can choose to ignore (but can NOT explain away) the fact that 
the apparent consensus of this thread that the JL 900 is clearly 'better sounding' than the PDX (wow!), even though the power 
ratings are marginal enough _to NOT make any audible difference._
End of story.

_Cheers!_

Rick


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## DS-21 (Apr 16, 2005)

neomsport said:


> this would make the benefits of Class A amps, which clearly exhibit lower measurable distortion, and tube "sound" amps as urban myths.


Good boy! You're learning! I'm proud of you!

(In truth, badly designed or out-of-adjustment tube amps do sound different. AND, on speakers with widely varying impedance curves - i.e. speakers that should never be used with glass amps - they can sound different. But generally speaking, well-designed tube amps adjusted properly sound just like other amps. The difference is that they have to be futzed with more often than solid-state amps. Also, some people prefer the looks of expensive lightbulbs.)



neomsport said:


> the apparent consensus of this thread that the JL 900 is clearly 'better sounding' than the PDX (wow!), even though the power ratings are marginal enough _to NOT make any audible difference._


There are probably some people stupidly claiming magic properties for the Jello amp. However, the broad consensus seems to be that the PDX's are noisy - I can't write to that, having never owned one or even to my knowledge "heard" one - whereas the Jello doesn't have that problem. That can make a sonic difference even though I agree with you, the power numbers aren't very different.

PS: There's no reason be a jingoistic, xenophobic bigot about things. ("PRC cheap component...) What's wrong with China? Do you think that Chinese people can't do everything that Americans can do? Personally, I would prefer my amp mass produced in a Chinese factory than soldered together on some American "high-ender" hack's kitchen table by hand...


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## ChrisB (Jul 3, 2008)

My main complaint about the PDX-5 that I tried in 2008 was the subwoofer channel (in addition to the noisy full range channels). IMHO, there is NO WAY that subwoofer channel output 300 watts RMS to my 13w6v2. I had to crank the heck out of the gain just to get some decent output, and it seemed to distort just as I was noticing the sub.

That same day, I put an Orion HCCA 225 G5 on the sub @ 2 ohms, and it seemed to provide more sound, even though it was only rated for 200 watts RMS at 2 ohms.

Of course NOW I have ways to measure the differences, if any, but no PDX amplifiers to play with. Go figure...


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## neomsport (Nov 25, 2009)

Well, so much for the theory that ALL amps sound the same...

And on a final note dude,

Just stop with all the inane, name-calling and assumptions and unwarranted
characterizations. WTF do you know about PRC amp vendors mindset and
motivations (less then you appear to purport you know about me).

That does not make me a bigot, only a pragmatist, who understands the
reality of the situation. Your arrogance + condesending attitude is truly
a wonder to behold.

I'm done.

Rick


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## Subirex09 (Nov 20, 2009)

I do not want to reignite the arguments that came up on this thread but I did eventually end up installing my PDX-5 and wanted to follow up.

I have yet to install my components and connect them to the amp, which may prove the noisy full range channels from what people have said, but I hope not!...but the sub channel sounds terrific and doesn't feel weak at all. I haven't ever tested the JL but I don't think I would find it necessary, especially for the price it is going for.

I am using an Audio Integrations sub enclosure with a PG RSDC102, I had to put a lot of foam into the enclosure to lower the volume since this sub runs best in a tiny box, but I have been truly impressed with the sub sound from the beginning and am still surprised sometimes when I crank a song I haven't heard yet. 

For the price I paid for the PDX, I have no complaints at all...but again, I am only using the sub channel at the moment.

Just wanted to give any potential PDX-5 buyers a bit of hope : ).


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## metanium (Feb 2, 2007)

Subirex09 said:


> I do not want to reignite the arguments that came up on this thread but I did eventually end up installing my PDX-5 and wanted to follow up.
> 
> I have yet to install my components and connect them to the amp, which may prove the noisy full range channels from what people have said, but I hope not!...but the sub channel sounds terrific and doesn't feel weak at all. I haven't ever tested the JL but I don't think I would find it necessary, especially for the price it is going for.
> 
> ...


I installed a PDX-5 in a friend's boat and it was absolutely great in that application. My buddy said his boat sounds like a night club! That's been my one and only experience with any of the PDX amps.

In all honesty, unless you do a lot of listening with the engine off (i.e. in your driveway), I don't believe a little noise (if it truly is present in the PDX's) is really gonna hurt you. With a little wind and engine noise (or a lot, like my buddy's boat) you can't hear it anyway.

I'm not really an Alpine fan at all. I used to use their HU's back in the day. My first was a 7903 pullout. Now JL, on the otherhand is my all-time favorite brand. Some say it's over-priced, but their amp and subs have not failed me through several years of use (and abuse).


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## Lateshow (Nov 30, 2010)

I just replaced an old mtx 4202 with the pdx-5 and it sounds brighter, but not as deep. I'm going to bridge it later to see if it will bring out my mids. 

I've read thru this thread and though JL is much better, the alpine is half the price. So for people on a tight budget, the alpine is not bad. It runs cool and has a tiny footprint. I'd love to try that JL and hear how much better everything would sound, but not for that much money. My whole system (besides whatever amp I use) cost less than that Jl amp. Hopefully, I'll like the way it sounds when everything is dialed in again. I didn't have a sub for over year. Before then I ran ss rp-l 12" (gave to cousin) and later an ascendant avalanche 12" (needs to be repaired) to brutus amp. These lil subs wont get anywhere close, but if I think they need more, I'll go back to the mtx up front and pull out one of my other amps for the subs/change em out. In the meantime, pretty impressed with this little amp. The layout, the speaker plugs, small and stackable (can fit 3 under the rear seat). I haven't paid anything for it (yet). It was sitting new in the box at my cousins along with the subs, but if it works out...


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## nineball (Jan 17, 2008)

Lateshow said:


> I've read thru this thread and though JL is much better, the alpine is half the price. So for people on a tight budget, the alpine is not bad. It runs cool and has a tiny footprint. I'd love to try that JL and hear how much better everything would sound, but not for that much money.



i find it amazing that you can tell that one amp is better than another when you have never owned it.


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## Lateshow (Nov 30, 2010)

nineball said:


> i find it amazing that you can tell that one amp is better than another when you have never owned it.


I find it funny that you missed the part about me reading everyone's post (even though you quoted it). Everyone recommended the jl over the alpine. Do they all work for JL? Is this a fake site set up by JL to promote their products? Either way, I'm not dropping that much cash to try to prove them wrong.

To quote...

Course, I could get a hell of a good look at a T-Bone steak by sticking my head up a bull's ass, but I'd rather take the butcher's word for it...


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## nineball (Jan 17, 2008)

yep, if most people say something it must be true and believed as gospel. at one point the entire world believed the earth was flat too.


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## Lateshow (Nov 30, 2010)

let me guess you work for alpine.


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## nineball (Jan 17, 2008)

Lateshow said:


> let me guess you work for alpine.


nope, and once again you arrive at a conclusion with no factual information. i'm done with you. in your mind you know what is best because someone else told you it was so there is no point in continuing this.


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## Lateshow (Nov 30, 2010)

nineball said:


> nope, and once again you arrive at a conclusion with no factual information. i'm done with you. in your mind you know what is best because someone else told you it was so there is no point in continuing this.


Good cuz you come across like an ass. My original thread states that I like the alpine for the money even though everyone else says the JL amp is better. Did you go through the threads to question everyone if they did a side by side or heard them both? No you didnt. You just jumped on me like if I was the new kid in school. Just cuz I accepted what a dozen other forum members stated as fact until I could find out differently. 

You come around and try to act all smug and condescending. The alpine thing was a sarcastic joke cuz I know you don't work for them. I knew an Alpine rep and he seemed pretty intelligent. I also knew the idiot who crashed the Alpine lambo now that could be you.

Maybe you didn't get enough recognition growing up. I am here to recognize you for the incredible prick you are. Dont come around starting **** you cant finish.


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## nineball (Jan 17, 2008)

Lateshow said:


> Good cuz you come across like an ass. My original thread states that I like the alpine for the money even though everyone else says the JL amp is better. Did you go through the threads to question everyone if they did a side by side or heard them both? No you didnt. You just jumped on me like if I was the new kid in school. Just cuz I accepted what a dozen other forum members stated as fact until I could find out differently.
> 
> You come around and try to act all smug and condescending. The alpine thing was a sarcastic joke cuz I know you don't work for them. I knew an Alpine rep and he seemed pretty intelligent. I also knew the idiot who crashed the Alpine lambo now that could be you.
> 
> Maybe you didn't get enough recognition growing up. I am here to recognize you for the incredible prick you are. Dont come around starting **** you cant finish.




welcome to the forum. so nice to have another member who contributes this way.


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## Lateshow (Nov 30, 2010)

nineball said:


> welcome to the forum. so nice to have another member who contributes this way.


Friend request sent in attempt to socialize you. We'll work on those social skills... You can be a better person!


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## nineball (Jan 17, 2008)

Lateshow said:


> Friend request sent in attempt to socialize you. We'll work on those social skills... You can be a better person!



keep trolling for post counts with meaningless garbage. build up that rep! i'd consider your offer but the other side has to be advanced in a topic for me to learn anything, and sadly that just isn't the case here.


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## Lateshow (Nov 30, 2010)

nineball said:


> keep trolling for post counts with meaningless garbage. build up that rep! i'd consider your offer but the other side has to be advanced in a topic for me to learn anything, and sadly that just isn't the case here.


Why so defensive? There's still hope. You don't have to get help from me, but go... get some help. 

Now if any pro knows how to bridge that alpine, please lmk.

Edit: Btw, why would I care about post count? You have tons and haven't shown me anything so far.


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## nineball (Jan 17, 2008)

come on, can't even bridge an amp? you posted in the thread where it spelled it out for you and you still can't get it? damn. maybe i can _show_ you how to do it with pictures since words seem a bit hard for you to understand. 

now you can get your last word in and be a happy camper. a discussion with you is pointless as you quickly reduce it to accusations and lame attempts at jokes and personal attacks.


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## Lateshow (Nov 30, 2010)

nineball said:


> come on, can't even bridge an amp? you posted in the thread where it spelled it out for you and you still can't get it? damn. maybe i can _show_ you how to do it with pictures since words seem a bit hard for you to understand.
> 
> now you can get your last word in and be a happy camper. a discussion with you is pointless as you quickly reduce it to accusations and lame attempts at jokes and personal attacks.


Lol you still don't get it. I give you an out and you start back up. The jokes were at your expense and were kinda funny. You, on the other hand, seem pretty lame. Petty even. I guess you must have been that kid. Sorry for that, but I'm not one of those bullies and acting tuff with me won't change what you went thru. Feel free to comment on spelling and grammar next since you aren't any help with anything else around here. 

I've gotten 2 or 3 different opinions on how to bridge this amp. They have 6 inputs (front rear sub) and these neat plugs for hooking up the out put. I'd rather double check then ass ume and mess something up. 
edit: got it. gotta play with settings and see if i want to keep now.


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