# Alpine PDX-5 finally came in! w00t!



## ZoNtO (Sep 20, 2005)

Well, Alpine finally shipped out these amps and I picked one up at my local shop today! Thought I would post some pictures for you guys since there's really not much on this bad boy yet.

As a side note before I post the pics, if anyone could direct me how to open up these PDX amps, I have no problems taking amp guts pictures. I'm not going to mess around right now though! 



































I was really impressed by the birthsheet and the 60A of total fusing. No regrets going with this bad boy considering it can go underneath my front drivers seat!


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## ErinH (Feb 14, 2007)

Birthsheet looks good.


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## yeldak99 (Mar 5, 2008)

I can't wait for my economic stimulus check.....


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## tcguy85 (Oct 29, 2007)

nice! 100x4 and 350x1 in one amp. pretty sweet.


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## bjayjr5679 (Nov 8, 2007)

only 2 30 amp fuses. Very nice class d.


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## Oliver (Jun 25, 2007)

That amp is either really small or you would have no problems playing a guitar


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## ZoNtO (Sep 20, 2005)

a$$hole said:


> That amp is either really small or you would have no problems playing a guitar


6'3" and I weigh like 155 lbs... Guitar's too frustrating though, I'd rather sing!


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## placenta (Feb 2, 2008)

yeldak99 said:


> I can't wait for my economic stimulus check.....


when do those arrive again?


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## tcguy85 (Oct 29, 2007)

seems like a real nice power configuration. should work well for a lot of people. would power a nice moderate powered active 2-way front stage and an efficient sub. nice, small, powerful and simple


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## ZoNtO (Sep 20, 2005)

tcguy85 said:


> seems like a real nice power configuration. should work well for a lot of people. would power a nice moderate powered active 2-way front stage and an efficient sub. nice, small, powerful and simple


You're thinking about one for your RSDs and Dayton aren't you?!?


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## ErinH (Feb 14, 2007)

I could see buying 2 of those and briding for individual L/R amps. Sub would be off one, though I guess.


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## tcguy85 (Oct 29, 2007)

ZoNtO said:


> You're thinking about one for your RSDs and Dayton aren't you?!?


it would power it all nicely, but i already have waaaay more power than that can make. why downgrade.


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## yeldak99 (Mar 5, 2008)

placenta said:


> when do those arrive again?



Social Security #s ending in (direct deposit):

00 – 20 May 2
21 – 75 May 9
76 – 99 May 16


Social Security #s ending in: (not direct deposit)

00 – 09 May 16
10 – 18 May 23
19 – 25 May 30
26 – 38 June 6
39 – 51 June 13
52 – 63 June 20
64 – 75 June 27
76 – 87 July 4
88 – 99 July 11


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## tcguy85 (Oct 29, 2007)

bikinpunk said:


> I could see buying 2 of those and briding for individual L/R amps. Sub would be off one, though I guess.


or use a dual voice coil sub, one on each coil.


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## FoxPro5 (Feb 14, 2006)

I tried and tried to get the cover off my 4.150 but just couldn't do it. Apparently Alpine doesn't want us to see how they get all those SQ dee beez in there. 

Make sure you take a pic when it's all fired up. This one guy here named Chad is a blue LED junky and would really appreciate seeing it's beautiful glow.


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## txbonds (Mar 10, 2008)

Theres pics of the 4.150 on ampguts.


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## ZoNtO (Sep 20, 2005)

txbonds said:


> Theres pics of the 4.150 on ampguts.


But the question is, how did they get the top off?


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## fredridge (Jan 17, 2007)

LOL 




FoxPro5 said:


> Make sure you take a pic when it's all fired up. This one guy here named Chad is a blue LED junky and would really appreciate seeing it's beautiful glow.


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## effenay (Mar 2, 2006)

ZoNtO said:


> But the question is, how did they get the top off?


From http://www.caraudiomag.com/0607_cae_alpine_pdx_4150_amplifier/

_Getting this amplifier apart reminded me of those 3D wood puzzles, the ones where you have to slide the right piece just a little this way to release that other piece so you can get the first piece out. Not that you'd ever void the warranty by taking an amplifier apart, of course, but I've got a license to disassemble (now available at Radio Shack -ed.). There is a single hex-head screw to gain access to the control panel in the front side of the amplifier for the installer, but everything else is a little mysterious. The base and endplates of the amplifier are cast aluminum pieces, the top plate is extruded aluminum, and there are three major cast plastic pieces in the exterior framework. In addition, there are three separate circuit boards: the main PCB, a small board for the lighting in the top panel and a daughter board attached to the bottom plate that contains the channel 3 and 4 input jacks and crossover/gain controls. All this is held together by lots of different screws, making this perhaps one of the most labor-intensive amps to assemble/disassemble I have seen in a long time._

In other words... not for the faint of heart.


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## Powers (Apr 10, 2008)

I'm looking at doing some PDX amps. So i've researched the hell out of them. They're amazing amps.


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## ZoNtO (Sep 20, 2005)

effenay said:


> From http://www.caraudiomag.com/0607_cae_alpine_pdx_4150_amplifier/
> 
> _Getting this amplifier apart reminded me of those 3D wood puzzles, the ones where you have to slide the right piece just a little this way to release that other piece so you can get the first piece out. Not that you'd ever void the warranty by taking an amplifier apart, of course, but I've got a license to disassemble (now available at Radio Shack -ed.). There is a single hex-head screw to gain access to the control panel in the front side of the amplifier for the installer, but everything else is a little mysterious. The base and endplates of the amplifier are cast aluminum pieces, the top plate is extruded aluminum, and there are three major cast plastic pieces in the exterior framework. In addition, there are three separate circuit boards: the main PCB, a small board for the lighting in the top panel and a daughter board attached to the bottom plate that contains the channel 3 and 4 input jacks and crossover/gain controls. All this is held together by lots of different screws, making this perhaps one of the most labor-intensive amps to assemble/disassemble I have seen in a long time._
> 
> In other words... not for the faint of heart.


And in other words someone else will have to post pics of the internals!


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## s10scooter (Feb 5, 2007)

Sorry, I cannot see photographs at work. Anyone care to post the birth sheet numbers for me?


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## TX_SS (Sep 21, 2007)

s10scooter said:


> Sorry, I cannot see photographs at work. Anyone care to post the birth sheet numbers for me?


102 x 4 and 361 x 1.


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## s10scooter (Feb 5, 2007)

TX_SS said:


> 102 x 4 and 361 x 1.


   
   
   

Glad I waited....


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## t3sn4f2 (Jan 3, 2007)

s10scooter said:


> Sorry, I cannot see photographs at work. Anyone care to post the birth sheet numbers for me?


102+361 at 14.4 volts though. I say 50% of that with the car off.


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## 99IntegraGS (Jan 18, 2007)

s10scooter said:


> Sorry, I cannot see photographs at work. Anyone care to post the birth sheet numbers for me?




```
[B]- ACTUAL TEST MEASUREMENTS - 

[U]TEST[/U]                          [U]SPECIFICATION[/U]                [U]ACTUAL[/U][/B]
Output Power (RMS)           75W min. (Full Range)          102W
(Per Channel)
Output Power (RMS)           300W min. (Full Range)         361W
(Per Channel)
```
Doh.... a little late.

JD


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## DejaWiz (Sep 20, 2007)

Very nice! This is on my list of wants. I'm happy to see the actual output is well above rated. Hopefully I'll have the $$$ together next tax return to get my Versa transformed.


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## Thumper26 (Sep 23, 2005)

very nice. maybe use two of them, and bridge channels 1 and 2 and then 3 and 4 and use one on each side for a 3 way setup, with a 1000.1 for the subs? :evilgrin:


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## dogstar (Jan 31, 2007)

I keep thinking one of these, with channels 1+2 for tweets, 3+4 for rear fill (I know I know...)
Add a 2.150 for midbass, 1.1000 for sub and use the sub channel from the pdx5 for a 6-8" sub up front.

Either that or a 4.100 + 2.150 + 1.1000.


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## ZoNtO (Sep 20, 2005)

dogstar said:


> I keep thinking one of these, with channels 1+2 for tweets, 3+4 for rear fill (I know I know...)
> Add a 2.150 for midbass, 1.1000 for sub and use the sub channel from the pdx5 for a 6-8" sub up front.
> 
> Either that or a 4.100 + 2.150 + 1.1000.


If you're going to go that fancy I would separate all your amps to save money that way. I contemplated getting a 2.150 to put under the passenger seat just for midbasses, but with all the reading I've been doing I really think that a 2 way crossing around 2500 - 3200 khz on the mid and tweet will be ample for my tastes, hence me getting this amp. I doubt I'll ever run more than the 350W to a sub anyway, single 12 or 15 is good enough for me too!


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## ViperVin (Mar 15, 2008)

oooo i want one.


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## scrape (Feb 19, 2008)

im definitely getting one of these, i was going to go 4.150 and 1.600, but lets be honest i probably dont need all that power, its plenty loud as it is i just wanted the added sq and bump


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## alphakenny1 (Dec 21, 2005)

if i was running 2 way + sub, i'd definitely get this amp. I like how they are underrated by 20-25%.


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## placenta (Feb 2, 2008)

Its a really good all in one solution. Not my style, but this one will be very popular. The footprint is the best feature. 

When is someone going to do some real technical tests with one? Someone send one to Dingaling.


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## ZoNtO (Sep 20, 2005)

scrape said:


> im definitely getting one of these, i was going to go 4.150 and 1.600, but lets be honest i probably dont need all that power, its plenty loud as it is i just wanted the added sq and bump


Exactly my reasoning!


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## ZoNtO (Sep 20, 2005)

Well an update since I've used it about a week or two. 

I have it set on 2-way, which gives front/rear/sub outputs from the RCAs. Set the gains to 28 on the volume control, this amp really makes my Infinity Reference components sound a ton better up front. Gains to rear speakers (Infinity Reference 6x9s was set about 25% less) and then I set fader to +10 on the HU to bring sound up front. The rear fill does add a little bit of stage width and top end sparkle as I've tested that out before.

I don't really notice any of the "weak sub" issues that a lot of people do with the 9887. I have the subwoofer voltage set to +7 on the HU. Subwoofer fading set to system 2 so it fades a little less than the other preouts with a reduction in volume. The gain on the PDX is about 75% up with this configuration and gives me great output with my Atlas 12 in a 1.5 ft^3 sealed box. It blends very well and after doing some tuning with my manual T/A measurements and switching the sub phase to 180, the system sounds dang nice with pretty good up front bass (my midbass is limiting me here, as well as the 12db sub xover slope). It drops down to 10 hz nicely on the bass cd runs, and gives me really good transient response on rock and stuff.

I do notice some hiss on a few songs with the volume turned up, but I'm 99% positive that it's because my source is poorly recorded. I listen to mostly "punk" stuff that a lot of you guys don't like. Stuff from Drive Thru records, etc... No hiss or anything with volume paused or at 0 which was a problem on my previous system. 

The amp is built solid! I haven't done any extended listening sessions, but after about 40-60 minutes with volume at 27/28 I reached under my seat and the amp wasn't even warm at all. It's very, very efficient. I have noticed a minimal amount of dimming on my dome light when I'm listening at 28 volume, idling in the parking lot with my headlights on. No dimming on the headlights in that situation.

I do wonder about the crossovers on the amp being better quality than the 9887 ones. I am using the amp right now to test it out: low ~65 hz LPF, front and rear ~80 HPF. I will post results in a few weeks when I switch over and do everything from the amp. It is not possible to turn the LPF switch to an "OFF" setting on the amp, just the xover knob and gain. You can switch the front/rear channels to HPF/LPF/OFF, the range is from like 40-400hz or so I think.

I'm very satisfied with it, it serves my purpose very well and I can't wait until I get enough money to get my active setup going up front!


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## typericey (May 13, 2006)

PDX-5, $399 on Woofersetc. That's a sizzling deal, IMO. I want one...


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## 96dak (Jan 28, 2008)

ZoNtO said:


> I don't really notice any of the "weak sub" issues that a lot of people do with the 9887.
> 
> The amp is built solid! I haven't done any extended listening sessions, but after about 40-60 minutes with *volume at 27/28 *


thats why you dont have the weak sub out problem. ive noticed a few that try to set up the deck at volume 22/24. at that point your not getting a strong enough input signal.


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## placenta (Feb 2, 2008)

96dak said:


> thats why you dont have the weak sub out problem. ive noticed a few that try to set up the deck at volume 22/24. at that point your not getting a strong enough input signal.


very interesting...


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## typericey (May 13, 2006)

hmm... my 9887's set at 22 too. gonna try setting it a tad higher and give you guys feedback if any.


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## tcguy85 (Oct 29, 2007)

96dak said:


> thats why you dont have the weak sub out problem. ive noticed a few that try to set up the deck at volume 22/24. at that point your not getting a strong enough input signal.


i guess that just isn't obvious to some people.


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## kimokalihi (May 27, 2007)

I didn't know they were THAT small! Damn!


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## 96dak (Jan 28, 2008)

tcguy85 said:


> i guess that just isn't obvious to some people.


no kidding, especially since ive read more than a few posts where someone has tested alpines preouts and they dont clip till theyre damn near wide open


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## typericey (May 13, 2006)

typericey said:


> hmm... my 9887's set at 22 too. gonna try setting it a tad higher and give you guys feedback if any.


ok, as promised, here's some news on what happened when i set my system to play at moderate listening levels when the 9887's volume is at 26: first, the bass levels did improve. but that's not the only improvement. i also noticed that my high freqs were more backward, and smoother. the little sibilance i used to hear is now virtually gone.

of course, your results may vary. it could be that my amp "liked" the extra juice that the 9887 was pumping out. in connection to that, my amp probably performed better with lower gains. 

whatever is the case, i think it can be safe to say that to a certain extent, the optimum volume level of the 9887 is in the vicinity of 26/27 and it sounds best when played at that level.


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## excelerater (May 23, 2005)

when using a small SUB channel of 350 watts like the alpine is offering
Can anyone make a few suggestions on what subs will produce good SQ and output with such a limited amount of watts ?

My experience says its hard to locate low powered extrodinary subs

????


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## tcguy85 (Oct 29, 2007)

excelerater said:


> when using a small SUB channel of 350 watts like the alpine is offering
> Can anyone make a few suggestions on what subs will produce good SQ and output with such a limited amount of watts ?
> 
> My experience says its hard to locate low powered extrodinary subs
> ...


a Dayton HO ten ported will have great SQ and should have plenty of output at that power level.


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## agentk98 (Oct 31, 2006)

And too think I had my money set on pair of matching eclipse amps. Now, this thread is making me think twice about it and considering getting the 1.600 and 4.150.
I've gotta stop reading new posts until after I buy stuff.


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## QtrHorse (Oct 17, 2007)

I was very interested in these amps and finally had the chance to see one in person. They are tiny nice looking amps. I had read about them and read peoples post about them and still was amazed after seeing them in person.


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## ZoNtO (Sep 20, 2005)

tcguy85 said:


> i guess that just isn't obvious to some people.


Yeah I thought it was common understand and practice among car audio enthusiasts to set gains to 75% of total volume level. 75% of 35 is about 27 but I like even #'s more so 28 it is!


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## ZoNtO (Sep 20, 2005)

Turned down the gain for the fronts a tad since running Imprint and that helped a bit. I think either my Infinity Reference components suck, are blowing (scratchy sound I'm assuming from tweeters), or are still receiving a tad too much power.

The hiss that's present with Imprint on isn't intolerable, but a little perplexing... Makes me want to try just manually time aligning the speakers and then EQ'ing the peaks out on my own. This amp is so brutally efficient I love it!


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## fej (Feb 8, 2006)

I have run the pdx's in my last 2 way front stage setup 4.150 and 1.600 on Pioneer 720 components in kicks and a 8w7 optimum sealed and it worked really well. 164w per on the 4.150 and 743w on the 1.600.

I think I might end up selling the 1.600 and using it towards this 5 channel option. With my new crew cab truck there really isn't any space to run 2 amps ... and I have no idea what I am going to try and do sub wise 

Thanks for the info on this amp.


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## jonnyanalog (Nov 14, 2007)

this thing sounds really cool...might just have to get me one!!! just not sure its gonna be enough power...hmmm
nice write up though Zonto!


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## ianbiz (May 13, 2008)

badass amp.


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## dejo (Jan 3, 2006)

I just bought the pdx 5 to save some space rather than using my PG xenons, they are huge. going to run (for now anyway) the prs mids with the seas neo tweets and a 15 ib


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## ZoNtO (Sep 20, 2005)

Alright so here's an update I feel is worth mentioning. Just drove back to Salt Lake City yesterday from San Francisco area so basically about 11 hours of driving. I had the volume no lower than 20 on the HU the whole time, up to 27 or 28 at certain points. Air con was not reaching the amp cuz I couldn't feel it with my hand underneath the seat. 

This little tank of an amp never went into protection even though it was pretty freaking hot near the end of the trip. It got hot enough that I couldn't keep my fingers on it for more than a couple seconds, but never gave out. Keep in mind this is under my driver seat with very little ventilation, so I have no problems recommending it to anyone worried about confining it or anything!

Awesome! Can't beat all the features and power for the 341 I paid for it! w00t!

On a side note, with cruise control set to 65-67 mph and minimal A/C, my 2000 Honda Civic EX couple (5 speed manual) got 40 and 41.17 miles per gallon both times I gassed up. This is with me, and probably about 70-100 pounds of extra weight of my luggage driving home (and the sub of course)! Can't beat that either for the 6200 I paid for it!


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## dejo (Jan 3, 2006)

I got my pdx5 installed. It does get pretty warm and fairly quickly too. didnt shut off on a 5 hour drive though. My birthsheets shows 110 rms on the 4 channel side and 378 on the sub channel.


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## Guest (May 27, 2008)

Dammit. I wish I waited for this. I found a good deal on my US Amps AX5600 5ch that puts out (rated) 75x4 and 500x1 @ 1ohm so it seemed like a good amp for me wanting to run a nice little 3-way setup. But now, it seems like the Xovers on the AX5600 are not going to work out for me, even though I have a Alpine 9835 HU. I'm thinking about selling it and going for the PDX-5. I'm going with an IB setup with my SS RL-p so 350-375w should be plenty.


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## jpndave (Aug 10, 2008)

ZoNtO said:


> Alright so here's an update I feel is worth mentioning. Just drove back to Salt Lake City yesterday from San Francisco area so basically about 11 hours of driving. I had the volume no lower than 20 on the HU the whole time, up to 27 or 28 at certain points. Air con was not reaching the amp cuz I couldn't feel it with my hand underneath the seat.
> 
> This little tank of an amp never went into protection even though it was pretty freaking hot near the end of the trip. It got hot enough that I couldn't keep my fingers on it for more than a couple seconds, but never gave out. Keep in mind this is under my driver seat with very little ventilation, so I have no problems recommending it to anyone worried about confining it or anything!
> 
> ...


Hey ZoNtO, where did you pick that unit up for $341? I would love to add one to my system.

Thanks!

Dave


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## phoenix (Jul 19, 2008)

a$$hole said:


> That amp is either really small or you would have no problems playing a guitar




hmmmm... very large penis. hopefully circumsized


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## ZoNtO (Sep 20, 2005)

Sorry guys, the emails for subscribed threads have been slow lately. I picked this up locally from an authorized retailer at cost + 10% when I was still working for a car audio shop. 

I think on either ike or woofers you can pick it up for 400 bucks, just make sure that you really CAN live with the 300-350 watts for the sub, otherwise it's basically a 4.100 as far as power goes. 

IMO the real advantage for this system is a 2 way active system with a traditional "SQ oriented" sub. I've had zero problems with mine and still the only time I've noticed it hot was driving all day long back home from california in blistering heat. 

Something else I noticed when thinking about building a ported box was the apparent lack of a subsonic filter option. After I called Alpine and checked the website specs again, I discovered it has a built-in subsonic at 15hz/ 24db slope. Very cool IMO, but keep in mind for you 10hz excursion fanatics. And of course, if you're considering for active use, you WILL need an external crossover of some sort as the built in ones stop at 400hz or so.


Oh and I played guitar for a year but I'm too impatient, I'll let the other comment slide and let your imagination wander!


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## -Rob- (Nov 24, 2008)

Hello all. New to the site...
Got my pdx-5 in yesterday.



















Im running a pair of cadence cvl 6k (6.5") for the front stage and a Cadence TXW 12A 4ohm svc sub. Head unit is also Cadence, (cd2000) but soon to switch that out because of some issues with it.
Now to decide what to do with the extra 2 channels!


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## WaTTsLOk187 (May 1, 2007)

-Rob- said:


> Hello all. New to the site...
> Got my pdx-5 in yesterday.
> 
> 
> ...



Replace your HU with one that can do Active up front and your 2 channels are now used


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## AAAAAAA (Oct 5, 2007)

Anyone know if the advertised dimensions include the speaker wire terminal clips or not?


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## quality_sound (Dec 25, 2005)

Probably not. Most manufacturers tell you to add 1/2-1" for the terminals on top of the listed dimensions.


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## inovativ (Nov 29, 2008)

Just got the PDX-5 installed. This thing is sweet! I currently have it pushing 4 Focal 6.5s, 2 up front, 2 in the rear and the sound is super clear. Within the next week or so, I'll have the 5th channel pushing a JL 10w3v3 (2 ohms). I'm building a custom enclosure for it. I'll post back and let everyone know how it goes.

alh


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## jeffbum04 (Oct 17, 2008)

I got my PDX-5 like 2 months ago, haven't installed it yet. My birthsheet said 104x4 and 414x1, I'll take a picture when I get the chance. Its gonna be running a 8w7 and i have a set of Alpine Type-X (SPX-137R I believe). I don't know what to get for the fronts, or if I should just run the type-x's for now.


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## therealdeal74 (Sep 9, 2008)

Is anyone who is using this amp having issues with low frequency response on subs? I have it powering 2 8" Earthquake SWS subs and it seems a bit weaker than I would expect...


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## inovativ (Nov 29, 2008)

No problems here. In fact, I've had to turn the gains down a bit to keep the sub from sounding too boomy. I'm pushing a JL Audio 10 in a wicked cas glove box enclosure. Sounds great!


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## ItalynStylion (May 3, 2008)

therealdeal74 said:


> Is anyone who is using this amp having issues with low frequency response on subs? I have it powering 2 8" Earthquake SWS subs and it seems a bit weaker than I would expect...


Yes actually. My friend has one and he told me that his low end on the subs seemed very weak. I thought it was odd since I have the same subs and love them to death.

I had a listen on his system and it sounded like he had a very low high pass filter on the subs, somewhere around 35-40hz. It would hit some higher sub bass notes VERY VERY hard in songs and then the low notes would be almost inaudible. 

I told him to play the song again while I went to the trunk and looked at the subs while they played. He started the track over and when the higher bass note hit the subs had good excursion but when that low note hit they barely moved at all. Like I said, it was like there was a low crossover that was causing a sharp roll off. 

I'll give him a shout and see if he figured it out.


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## Hillbilly SQ (Jan 26, 2007)

ItalynStylion said:


> Yes actually. My friend has one and he told me that his low end on the subs seemed very weak. I thought it was odd since I have the same subs and love them to death.
> 
> I had a listen on his system and it sounded like he had a very low high pass filter on the subs, somewhere around 35-40hz. It would hit some higher sub bass notes VERY VERY hard in songs and then the low notes would be almost inaudible.
> 
> ...


Have you jumped his rca's over to your amp to see if it isn't his processing? That said it's obvious Quang isn't the only one with this issue. Is there a switch on the amp for a subsonic? Dejo had an exodus 15 on his pdx5 and it had no problem digging down into the 20's.


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## Booger (Apr 27, 2007)

No Problems AT ALL with mine!

Love it.


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## azngotskills (Feb 24, 2006)

It has a built-in high pass, this is via Crutchfield: LCD TV, Car Audio, Home Theater, Speakers, Plasma TV



> The mono channel also has a fixed 15 Hz, 24dB per octave subsonic filter to eliminate power-robbing super low frequencies that can also damage speakers.


http://www.crutchfield.com/p_500PDX5/Alpine-PDX-5.html?search=pdx=5&tp=115&tab=detailed_info


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## Hillbilly SQ (Jan 26, 2007)

azngotskills said:


> It has a built-in high pass, this is via Crutchfield: LCD TV, Car Audio, Home Theater, Speakers, Plasma TV
> 
> 
> 
> Alpine PDX-5 5-channel car amplifier 75 watts RMS x 4 + 300 watts RMS x 1 at Crutchfield.com


That still doesn't answer the question as to why some are digging deep and others aren't. 15hz subsonic shouldn't effect the sound where it matters.


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## azngotskills (Feb 24, 2006)

Hillbilly SQ said:


> That still doesn't answer the question as to why some are digging deep and others aren't. 15hz subsonic shouldn't effect the sound where it matters.


You are correct, i was just answering the question 

Are you sure these are accurate frequency points? (ie 40hz, 35hz, 20hz)?
What application because different boxes, alignments, enclosure (sealed, ported, IB), cars, and orientation make a difference?
What are you expectation of how a sub should sound?

Me personally, I didnt think that the PDX-5 had the "balls" of other amps I have used. Dont get me wrong, the power/footprint ratio was great but maybe a design issue? Fullrange class D? Alpine?


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## ItalynStylion (May 3, 2008)

Hillbilly SQ said:


> Have you jumped his rca's over to *your amp *to see if it isn't his processing? That said it's obvious Quang isn't the only one with this issue. Is there a switch on the amp for a subsonic? Dejo had an exodus 15 on his pdx5 and it had no problem digging down into the 20's.


My amp......MY AMP?!?!?


Chris....that hurts man


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## therealdeal74 (Sep 9, 2008)

Bob Norvelle cited a PDX amp for poor low frequency performance in the Car Audio mag review.

Alpine PDX 4.150 Ultra Small Amplifier - Car Audio & Electronics Magazine



> Although lacking a little in low-frequency performance, it had stunning sound quality in the low-mid to high frequencies, which is probably what it was designed for.


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## releasedtruth (Feb 1, 2009)

So you get a relatively strong sub channel that just can't perform and if you twin with an already poor bass performing Imprint, double trouble?


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## notfast (Mar 20, 2009)

therealdeal74 said:


> Bob Norvelle cited a PDX amp for poor low frequency performance in the Car Audio mag review.
> 
> Alpine PDX 4.150 Ultra Small Amplifier - Car Audio & Electronics Magazine


Bob did not cited a PDX amp for poor low frequency performance.

_All in all, I was very impressed by this amplifier. Although lacking a little in low-frequency performance, it had stunning sound quality in the low-mid to high frequencies,_

NOT POOR, just lacking a little compared to the low-mid to high.


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## vuelamanuel (Apr 22, 2009)

Hi,
Newbie here. I think that the problem has to do with the topology of the switching amp (class "D") vs a regular class A/B. A full range class D amp uses a cap between the Output transistor and the speaker (to smooth out the discrete response); the caps drops the damping factor so the speakers feel less controlled in the lower frequencies than in amps with higher damping factors...
However, the SUB channel is a completely different design that probably has a much higher damping factor (no need to "smooth" the high freq harshness since you are going to filter it out anyway). Check your H/U RCA out, the problem could be there.

I think Rockford has actually shunned the class D design because they can get better damping values...we compared side to side a JL300/4, a T400-4 and a PDX.100 and both A/B amps were more similar than the PDX...the PDX was sligthly cleaner in the middle, both other amps had better midbass (I was surprised with the RF, but it was probably because I was running out of a Battery, probably the regulated supply of the JL makes a difference in a running system with an alternator connected). 

In short: the PDX should have as much "lower balls" but probably not as much "upper balls". Check the input voltage to the Sub channel....


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## vuelamanuel (Apr 22, 2009)

DOUBLE POST


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## releasedtruth (Feb 1, 2009)

Now that I have a PDX-5 I can weigh in a little. I had my sib running on a 500/5 before so it was still class D sub channel, but 250w instead of the rated 418w on my PDX. I will say it doesn't feel any stronger than the JL, but haven't taken it too far just yet. 

The other channels seem to work well enough, but I'm running through an H650 Aux so god only knows how much noise I'm adding with all these cables and knobs...


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## t3sn4f2 (Jan 3, 2007)

releasedtruth said:


> Now that I have a PDX-5 I can weigh in a little. I had my sib running on a 500/5 before so it was still class D sub channel, but 250w instead of the rated 418w on my PDX. *I will say it doesn't feel any stronger than the JL, but haven't taken it too far just yet.*
> 
> The other channels seem to work well enough, but I'm running through an H650 Aux so god only knows how much noise I'm adding with all these cables and knobs...


JL rates their amps more strictly compared to Alpine method when going off its birth sheet numbers (at a lower THD % and lower voltage). I'd say they come out to nearly the same wattage output (in the sub channel) when compared equally.


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## ZoNtO (Sep 20, 2005)

Well, I guess I can't really compare it to anything, but I'm not complaining about the bass output of my PDX-5. I have my sub voltage usually to 1 from the 9887 or 2 if I'm on the freeway.

Imprint is done. Atlas 12 sub sealed up in about 1.5 ft^3. Sure it's not going to "impress" anyone with it's volume, but it's tight and blends awesomely! I'll crank voltage up to 10 if I have rap playing, but for rock I just leave it at 1.


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## VP Electricity (Apr 11, 2009)

notfast said:


> Bob did not cited a PDX amp for poor low frequency performance.
> 
> NOT POOR, just lacking a little compared to the low-mid to high.


Based on the state of the art and the competition, and considering what reviewers at magazines were allowed to say about possibly their biggest advertiser, I'd say that "poor" isn't an overstatement. How about "weaker than it should be"?


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## AlohaMark (May 3, 2009)

Has anyone installed this amp vertically? That's how I would like to orient it so it fits where the stock amp is ( 02 E39). But on the Crutchfield web sight it states:

*Notes: Do not install this amplifier vertically or at an incline. Any installation other than parallel to the vehicle floor, invalidates the warranty.*Alpine PDX-5 5-channel car amplifier 75 watts RMS x 4 + 300 watts RMS x 1 at Crutchfield.com


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## The Drake (Apr 3, 2007)

I had a 4.150 mounted vertically for several months before and never seen any problems, but I dont know if the manual says not to mount vertically for the 4.150 either, could just be the PDX-5's that say that. I just know I never had any issues when it was mounted vertically or now that its mounted horizontally.


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## AlohaMark (May 3, 2009)

The Drake said:


> I had a 4.150 mounted vertically for several months before and never seen any problems, but I dont know if the manual says not to mount vertically for the 4.150 either, could just be the PDX-5's that say that. I just know I never had any issues when it was mounted vertically or now that its mounted horizontally.


The manual on Alpine's web sight says this in the owner's manual for the 4.150:
Note:
Stack installation should always be parallel to the vehicle floor – do not install at an incline, such as
leaning against a vertical surface, as this will invalidate your warranty.

Alpine Electronics of America, Inc. - PDX-4.150

Glad your amp is still kickin! Anyone have any ideas on why the manual states this?


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## mjgonegm (Jun 21, 2008)

i got a better question how would they know if it was mounted that way anyway ??? seems stupid i wall call them to check.


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## The Drake (Apr 3, 2007)

AlohaMark said:


> The manual on Alpine's web sight says this in the owner's manual for the 4.150:
> Note:
> Stack installation should always be parallel to the vehicle floor – do not install at an incline, such as
> leaning against a vertical surface, as this will invalidate your warranty.
> ...


My first guess would just be for heat dissipation, the top is where the heatsink is so putting it on its side the heat will build up on the components rather than the heatsink and could potentially damage them if it gets too hot. Alpine could easily tell if it was sent in for repair under warranty by seeing that the components damaged/burned out were just on one side of the amp. Just a guess though, I could be completely wrong.


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## trebor (Jun 30, 2008)

They are specifically talking about not mounting vertically only if you are stacking the amps on top of each other. My guess would be that mounting solutions could fail.


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## AlohaMark (May 3, 2009)

AlohaMark said:


> Has anyone installed this amp vertically? That's how I would like to orient it so it fits where the stock amp is ( 02 E39). But on the Crutchfield web sight it states:
> 
> *Notes: Do not install this amplifier vertically or at an incline. Any installation other than parallel to the vehicle floor, invalidates the warranty.*Alpine PDX-5 5-channel car amplifier 75 watts RMS x 4 + 300 watts RMS x 1 at Crutchfield.com


OK so this is directly from the PDX-5 manual:

Note:
When stacking amplifiers, do not install horizontally or at an incline. Any installation other than
parallel to the vehicle floor, invalidates the warranty.

http://vault.alpine-usa.com/products/documents/PDX-5%20OM.PDF

Why does the Crutchfield warning differ from the Alpine manual? Looks like you can't trust the Crutchfield descriptions.

But if you read the Alpine note carefully, it states not to mount then HORIZONTALLY or at an incline. I''m sure they meant to say VERTICALLY, just like the 4.150 manual stated. 

So, it looks like you CAN mount it vertically, you just can't stack them vertically. Everyone agree?


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## breadysmith (May 19, 2009)

That's what it sounds like to me, you can stack them vertically, but not horizontally. Then it sounds like if you have just one you can mount it any way you want, its seems that the stacking becomes the issue.


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## toomtoomvroom (May 18, 2009)

jeffbum04 said:


> I got my PDX-5 like 2 months ago, haven't installed it yet. My birthsheet said 104x4 and 414x1, I'll take a picture when I get the chance. Its gonna be running a 8w7 and i have a set of Alpine Type-X (SPX-137R I believe). I don't know what to get for the fronts, or if I should just run the type-x's for now.


Hey Jeff, did you ever get a chance to hook it up to your 8W7? I have a Alphasonik PMA5753A and a PPI PC6600 which work but i don't think give the sub enough power. How does the Alpine do with the 8W7?


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