PDX-5 vs. XR-5S vs. ?

I am considering upgrading my amp. Currently I have a Pioneer p4300dvd feeding a Rockford T400.4, feeding a set a Focal components in the front and an ArcAudio 10" sub. I have a set of Pioneer 2-ways in the rear doors for rear fill, coming off the HU's power. I listen to mostly rock, new and old, along with a bit o' jazz.

Reason for upgrading is that I would like a bit more thump from the sub. The RF is straining a bit to get to where I want it and it's right on the clipping boundary. Bridged output on the RF rear channels is rated at 200W, but the "born on" doc reads 240W. I've tuned the gain via DMM for 225W.

I am thinking of upgrading the RF amp to an Alpine PDX-5 or a Kenwood XR5S. Looking for some input on how to choose between the two. They are similar in price, power and features, so looking for a decision point between the two.

Would consider input on something else, but want to retain the single amp (4+1 channels), small form factor and the price point.

Any input from the big swinging AV-diks out there??

 

Space constraints?
Need all connections on one side?

4 ohm power for the sub, I am guessing based on bridged outputs on the amp?

 

My amp board is about 14.5 x 17, it's a SoundOffAudio double sub box, with one sub box cut off so it fits behind the passenger side rear seat. The RF amp is mounted horizontally and is at the horizontal size limit.

I can work with the power, speaker and sub connections on the bottom, with the tuning controls on the top. The Rf has the connections and the tuning on the same side.

Yes, 4ohm load to the amp (DVC 2 ohm sub wired in series).

 

Out of those two I would go with the XR-5S. I think the PDX line is great, but with all the noise issues with the older PDX-5, I don't see a really good reason to use it over the Kenwood. Other good options would include the MRX-V60 (speaker + power on left/input + controls on right) and the JL XD700/5 (all wires bottom with tuning controls on the face of the amp.)

 

What's the Bridged rating of that RF amp? It doesnt take much power to get a Arc 10 moving.

 

I have the Kenwood mounted under the seat. Does the job for the price I paid. No issues what so ever.

 

Reason for upgrading is that I would like a bit more thump from the sub. The RF is straining a bit to get to where I want it and it's right on the clipping boundary. Bridged output on the RF rear channels is rated at 200W, but the "born on" doc reads 240W. I've tuned the gain via DMM for 225W.


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No, you're right, the Arc10 is rated for 250W RMS, but my biggest concern is that I'm too close to the clipping line right now. I would like a bit of headroom.

 

Interesting. Hadn't heard about noise issues from the pdx-5, but have read the the XR-5S does have a lower noise floor then the PDX.

From what I saw it looked like the V60 was a lower line amp. Not true? As for the JL, two problems for me, price point is higher (not a huge amount, but still), and worse my sub is a dvc 2ohm so I have to wire it to 1 or 4 ohms, the JL's sub power drops to 180 for a 4 ohm load and it doesn't list 1 ohm as doable.

 

The older PDX5's had high noise floors if I remember correctly. I think they are good now but you'd have to know when yours was built.

 

Thanks for the input so far. Still looking a a decision point, or points, though. Only thing I have so far is that he the XR-S5 has a bit more power and a bit lower noise floor, assuming a current model PDX anyway. That it??

Price points are about the same, so unless I find a killer deal somewhere, "sounds" like the XR-S5 would win by a nose.

 

The thing that would worry me, is how you set the gains.

If you did the traditional method of a test tone, 3/4 volume, and a DMM (which is sounds like), then you set it up to only put out the max power when you meet those conditions - in when listening to music, unless you are rocking a full tilt, you dont get close to that.

The difference in 225w and 350w is not that great - to the point that I dont think its worth spending the cash for, unless you want to.

I would personally grab a pretty dynamic track, crank it to your max listening volume, and adjust the gain by ear.

Another trick, if you have a DMM that remembers max or peak, play that dynamic track and crank it, see what your amp is actually putting out, and adjust from there.

Then, if you think you want a little more, look into new amps.

 

Headroom isnt going to give you more "Thump". The ARC 10 just might not the sub your looking for. By Thump do you mean more impact, louder or lower? Just upgrading your amp my not solve the problem.

 

As usual, we're going further into this then I thought, so I hadn't added huge amounts of detail, but we're here now .

Yes, I set the gains to 225W's of voltage via a 50Hz test tone at 3/4 volume with all equalization settings to flat. I then check the sound by ear and by the JL Audio IPad RTA, usually adding a couple of db equalization at the high and low end. When cranking a track, a bit below the volume setting used for the gain max, the RTA starts spitting out "clipping detected". Now, my ear is not tuned well enough to pull the beginnings of clipping from the sound, so I go by the RTA. Might be my first failing....

Given this, I was wanting a bit of headroom to stay away from clipping, not to make it louder, but I do want the 225W's worth of power as that seems to be needed to properly balance the sound, as least for me anyway.

I can make it sufficiently loud with the RF amp, but I want to use the Arc10 to it's fullest without also worrying that my 16 yo son will feel his oats one night and "over-clip" it. My other option for the 16yo problem is to down-gain the sub channels on the RF, but that makes the sound so flat that it's just boring.

Also class D vs. class AB has some benefits.

BTW, I actually had the gains set up higher then the DMM max, and that gives me a good balance between sub and the rest, until I crank it up, then the sound starts to get ugly too early, I assume since I am clipping.

Just haven't been able to find the happy medium between the sub and the Focals without overdriving the sub channel.

One last thing, when I tune the gains by ear for a cranked track, I can get it set well for ear-bleeding territory, but then the sound just goes flat at low volume. Am I asking too much to get a setting that sounds reasonable over high and low volume settings?

Sounds like I'm thread jacking myself......

 

Yeah, bad description on my part. I can get most of the "thump" that I want with the RF, but to maintain a good sound at lower volumes I need a bit more power at higher volumes than the RF can generate in order to balance out the front Focals. Lowering the gains on the Focals just causes the low volume sound to sound flat.

IOW, if I set the sub gains to what sounds good at low volumes, then I clip at the higher end. I'm out of amp before I'm out of sub.

 

Since I seem to be jacking this thread from "what amp" to "gain and tuning", let me ask another question. On the RF amp, my gains settings go from 0-10 (just to give an idea of the gain range). The sub is set right now at 5, while the front channels (Focals) is set at 3. While increasing volume, does having the gains set like this cause the sub channel and the front channels to increase in volumes at a non-linear rate to each other? IOW, does the sub at 5 increase in volume more then the front channels at 3, assuming a single volume knob increase on the HU?

 

I will let the guys with more knowledge than me deal with the gain setting issues. I was concerned about the same thing, but everything I read puts this amp as the value champ in the Alpine lineup. It pulls a lot of features from the PDX line, probably too many for Alpine to not update the PDX-5 soon, and does it for less. Most people are seeing around 400w @ 2ohms on the sub channel, again, like the PDX-5.

Another benefit, if you care, is that you can use the

$40 RUX-KNOB Remote Bass Level Control Knob for PDX-M12 and PDX-M6

RUX-KNOB remote gain control on the V60. Like you, I was disappointed with the dynamic disparity between high and low volume. The music just seems to fall so flat. I am hoping that I can use the remote bass knob to allow me to keep a more dynamic sound at the lower volumes I typically listen at. I figured it was worth the $25 to find out.

 

If you are running the rear off the deck then look into a HD600/4 like I did but I ran the JL components into 2 ohms (running 2 sets of components) off the front two channels to 75w each and ran the sub in the last two channels bridged for 300w.

 

The way that I understand it....do not think of gain from the amp as volume. Gain is power...not volume. You maximize the gain for each speaker set without producing distortion. Volume should increase equally despite the gain settings on all channels. I am not an expert....but I slept in a Holiday Inn Express once.

 

I forgot to mention....I recently had an Alpine PDX-5 installed and am very happy with the output. I have Focal 165 KR speakers up front....sounds great.

 

My HU has the ability to vary the sub output from -18 to +6 db, This is not equalization, from my understanding, but more of a HU gain control. I am currently using this to help with the low to high volume, but wasn't sure if this was how best to do it, or if it was a tuning problem that I should be able to get around.

Thanks for the input on the V60,might have to look closer.

Thanks for the input, appreciate it. I am aware that the gain is a component matching setting and not a volume control. I was exploring whether having that high a variance in gains between channels in the same amp would cause variations in the sound output at different volume settings. If so, I could see this as being part of my problem getting this dialed in. Entirely possible that I am expecting too much.

Thanks for everyone else's feedback. Anyone or anything else?