Your take on Polk PA500

modmx

hey everyone

anyone own a Polk PA500 amp? I'm thinking about getting one to power my polk sr6500s and polk mm651's. I was originally planning to use the money on a JL 450/4v2 but figured I should save the money on that and invest it into a better headunit (thinking about the clarion drz9255).

Any opinions? Any thoughts on how this baby would fair against the JL 450/4v2?

arun1963

The pa500.1 is a clean amp. They put out 4x90 watts rms. Have'nt heard the JL but the polk is prob better vfm, without any compromise on quality. I have no issues with mine. If you were going to run 200rms speakers, then you may feel they are a bit undercooked. For the speakers you're running, 100-125rms, they are perfect.

hu's like the 9255, pio 880, alpine+imprint etc give you the ability customise the sound in your car, relative to your cars interior and your seating position. It allows you to set the sound stage in front of you. Just like you'd have in 2ch home set-up, where the speakers are normally in front of you. In your car the speakers are to your sides, but the sound presentation would be frontal and above the dash height. The sq holy grail is about how accurate/lifelike and detailed you can make this stage.

If this is why you're looking at the clarion, then bi-amp the sr's and disconnect the rears. Start with running passive and once youre settled in go active. Running rears however, will always pull your stage backwards. As also cause frequency cancellation issues. You have'nt mentioned if you are running a sub. If not you can add that down the line and have a complete setup.

You may ofcourse be buying the hu for reasons other than given above , In which case yes its a good unit as are the others.

modmx

arun, thanks alot for the insightful post.

regarding the system, i do plan on purchasing dual kicker 12" L5s, running off a JL g-max amp

I'm not too familiar with tuning and installing of car stereo systems but that sound stage is something I would to achieve in my car. I am building a system for the best SQ at around $2500. Being a huge metallica fan, i would love to recreate a metallica concert in my car.

Could you elaborate on the "bi-amping" possibility a bit more?

MacLeod

Im running my beloved SR6500's off the PA500.4 and did so all of last season and did pretty well. Never finished worse than 2nd all year.

Its a very powerful amp and makes no noise. What more can ya ask?

The only downside is its freaking huge! Make sure youve got some space.

arun1963

You have great speakers (the sr's), the pa 500.4 is an excellent amp for them and your hu choice is good. Now all you need is a good sq sub setup. Your budget would allow you to look at good sq brands so listen to them and compare.

Before you decide on a sub its important to know what an sq sub is all about. A good sq sub would do the following and then some:

1. Play all the low frequencies exactly as recorded, not just a few bands. It would be free of design and manufacturing limitations that would cause it to boost or attenuate frequencies from the original sound.

2. The driver would have to be dynamic to handle the fastest transient bass notes without leaving ghosts (the previous bass note lingering and colouring the current note that is playing). The focus would be on reproducing and highlighting fine details rather than raw bass.

3. It would blend with the rest of the sound seamlessly. You would use your sub to play the frequencies from say 15hz (which you feel more than hear) to say about 60-70hz. Thats it. You dont want the sub playing higher than this. Your comps would take over from about 50-60hz upwards. You're only using the sub to 'fill in' the low end frequencies, that your comps cant reproduce accurately. Although the sr mids play well down to the 20's. The idea is to maintain the balance of sound. You have three drivers (sub, mid, tweet) playing three different frequency ranges. No one range should dominate the other and there should be a seamless transition from one range to the next.

The SR subs are excellent sq subs. Great quality and vfm. You can also look at stuff like seas lotus series, idq, JL 7's which would cost a bit more than the sr 124dvc.

With a sub its not about the driver alone. Its also about getting the enclosure right, both type (ported / sealed) and size. A good 12" dvc in a sealed box with a mono amp putting out 600watts at 2ohm should be fine. Ofcourse you would have to match the subs rms rating with that of your amp. I'm just giving a rough ball park idea.

Will take up bi-amping in tonites post. I downloaded the 9255 manual last night and there are some issues that I would like mac to comment on.

arun1963

Bi-amping:

There are two ways you can hook up your front comps to the amp. The first is where you run your two front comps of the front two channels of your amp (like its mostly done). The other way is to connect each driver to a seperate amp channel. So you would use all 4 amp ch's to drive a pair of components.

This gives you flexibility in tuning each driver independently, which is essential while setting your stage and imaging. It is also essential while linking your 5 drivers (front comps plus sub), so that when you hear all the speakers together the sound is cohesive.

The other benefit of bi-amping is that, with a regular connection, (pair of components off two amp ch's), each channels output is being shared between two drivers. With bi-amping each driver gets the full output of the amp channel.

For instance if you were hooked up the sr's to two channels of the polk 4ch, a pair of drivers would be sharing 95 watts. With bi-amping each driver would be getting 95watts. Good comps sound best closer to their rated power. The sound would more detailed and hence clearer.

Bi-amping is one of the building blocks for the foundation on which you would build your stage.

arun1963

Clarion 9885:

I was looking at the hu's manual last night and I found the eq function on it, to be quite different. While it gives you seperate left and right control, it does'nt give you independent control over a frequency. Rather, the range 20hz-20khz is broken into five bands and in each band you select a central frequency and the Q and all frequencies in that band will be equalised in a bell curve around the central frequency you selected. The steepness of the curve would of course be governed by the selected Q value.

Now, if I look at my eq's graphic display and break it up into the same bands, I see a few bell's, but also some more radical highs and lows. So, I'm wondering how good the clarions eq would be in setting an accurate stage / image.

arun1963

Slight correction.

It is also essential while linking your 5 drivers

Independent driver control while bi-amped, lets you basically level match between the drivers. Linking of the drivers is done with time alignnment.

All this will start falling into place once you have the setup installed.

modmx

arun, thanks for all the great insight. really appreciated. Mac, you too, your posts are always helpful.

Arun...would the coaxials in the back be sufficiently powered just off the HU's internal amp? Also, would dual Polk SR124's be overkill pushing out 1200w RMS be overkill?

arun1963

I would set up with comps upfront and the sub/s and listen to it. If you still feel the need for rears you can add them at that point. How often do you carry passengers in the back seat?

Yes, you can connect the rears to the hu, but when you turn the volume up, the amp in your hu may start clipping and send a distored signal to the rears. So yes, you can do it but if I had to run rears I would amp them.

2 subs will play louder than 1. For sq, you need a perfect balance between the frequencies that the sub/mid/tweet play. You don't want any one range dominating the others. Its also worth noting that with sound, everything is linked and connected. So if you bumped up one range, in this case the sub frequencies, not only would these frequencies play louder, but they would also affect frequencies upto say the 500-600hz range. Everything from 15hz to say 500hz would become fatter, with adverse effect on the stage and image.

You could ofcourse then tune down these frequencies, or increase the others to try and re-establish the balance, but with my very limited experience both have their own problems. The sound just gets either to tight and compressed and losses its airyness or it gets too thin. Also, if you do either then it kind of defeats the purpose of running two subs. Again this is my opinion based on my limited experience.

There are a lot of people who run two subs, so if thats what you want and like, do it by all means. You can also look at running 1x15" sub. The 15"s play the 10-20hz range much tighter and more accurately than a 12". Becoz they move more air than a 12' they would also play a bit louder. I think 1x15" would be between 1x12" and 2x12" in loudness but with much greater clarity and control. BTW what vehicle is this stuff going into?

Whatever little I know today is largely thanks to mac and some others on this forum. So yeah if you hang around here a bit, chances are you will get a ton of help from mac. It all depends on how far you want to go.

MacLeod

Head units are a horrible power source. If youre just set on using rear speakers, its best to amp them.

A pair of SR's getting 600 watts each being overkill depends on how you set it up. If you set your gains or sub level properly so that they blend in well with the front stage then theyll be fine and have plenty of headroom left over for when you just want to blast the bass.

modmx

all this is going into a 97 Nissan Pathfinder.

macleod, do you run rears?
arun, do you have any knowledge into Nakamichi headunits? would dropping down to Nak Cd400 have a noticeable effect on my sq? the price is a good $600 cheaper, for which I could buy better SQ subs

cadenceclipse

mac dont run rears. how much 4 cd400? check out eclipse? maybe drop to 1 sub like eclipse 8000 use left over $$$ from sub, box, interior speakers(just do 1 sr6500), and amps and get sompin like audiocontrol dqxs and nice HU, say eclipsecd5030

MacLeod

Nope, no rears for me.

Im running a set of SR6500's biamped off a 500.4 and a single SR124DVC running off a 1200.1 with Alpine source and processing.

modmx

heres my concern with not running rears, let me get your 2 cents on this. If for example I am playing metallica's S&M or Iron Maiden's live album, youve got the stage in the front and the crowd in the backdrop. If I were to disconnect the rears, I feel that would take away more of the "surround" sound aspect...while mainting that frontal sound stage. Is this a genuine concern or something that would not be effected by disconnecting my rears?

my car being a pathfinder SUV, I think it might be a different scenario concerning rears compared to a coupe or 4x4

arun1963

my $0.02.

The live album would have been recorded using at least 10-12 mics. Each band member would have got 1, some maybe more than 1. The back ups if any would get theirs, a few centre stage mics and a couple mics pointed towards the audience. When you listen to the music the stage would be in front of you and you would be a part of the audience. At the end of the number when the crowd breaks into applause and the recording switches to the mics aimed at the audience, you would feel like you were on stage with the band looking out at and hearing the 10's of thousands of cheering fans.

IMHO if youre really aiming for the stage and image, any rears in any vehicle will pull your stage back and the effect will never be the same.

You have a budget of $ 2,500. Keep 200 aside for rear coax's or 6x9's. Add this at the end if you're not satisfied. Build the rest of your set up around the bal 2,300. More than enough.

Re your hu ques, yes I would go for something other than the clarion. Its hellishly expensive and I just find the eq process on it to be strange. To set the stage and image you need to control the following

1. Time alignment
2. Independent control for left and right over at least 10-12 frequencies between 20-20khz. The more frequencies you can control the clearer the image.
3. Variable slopes, 36db for the sub and 6-24db/oct for the mids and tweet.
4. Bi-amping
5. An active network. You can do it in passive mode as well but active is better.

So you either need a hu that will allow you control over 1,2,3 and 5. Or you would go with a hu+processor option.

The naks are excellent decks, though sometimes prone to engine noise. The nak 400 would not give you control over the points given above. So you would need to get a processor. Also, youre running a 4ch amp so you may want to look at a 'dead head' + processor (hu without an internal amp) or a hu with the option of turning off its internal amp. This makes the signal cleaner. On my pioneer p-800 I have the option to turn the hu's amp off. I can hear the slight diff when i turn it on and off. However it would perfectly ok to run the nak 400 with say the RF360.2.

Some possible options:

1. Nakamichi 700 mkII +rf360.2
2. Eclipse units - Candence can help you here he runs eclipse. + rf360.2
3. Pioneer p-90 head unit plus the pio processor
4. Alpine+ processor - mac runs this combo.

Alpine is known for its sweet sound.

MacLeod

modmx wrote: »

heres my concern with not running rears, let me get your 2 cents on this. If for example I am playing metallica's S&M or Iron Maiden's live album, youve got the stage in the front and the crowd in the backdrop. If I were to disconnect the rears, I feel that would take away more of the "surround" sound aspect...while mainting that frontal sound stage. Is this a genuine concern or something that would not be effected by disconnecting my rears?

my car being a pathfinder SUV, I think it might be a different scenario concerning rears compared to a coupe or 4x4

That doesnt happen. The rears are playing the same thing the fronts are UNLESS youre listening to SACD or 5.1 audio. Regular CD's are recorded in 2 channel stereo so when youre listening to a concert CD, the crowd noise is in the front AND rear.

The problem with using rear speakers is that since theyre playing the same thing the fronts are BUT are hitting your ears at different times since theyre further back, it causes cancellation and smearing of detail. Plus it pulls your soundstage to the rear.

Front speakers dont ruin the sound quality but youll never achieve the best SQ with them.

Also, by not running rears, you can spend the money you wouldve spent on them on something else like better front stage speakers or a whole lot of Dynamat. Dynamatting the crap out of your car will go a whole lot further in a better sounding car than a set of rear speakers.

arun1963

the crowd noise is in the front AND rear.

True.

On the hu issue, I would go with the pioneer p-800. For a few reasons:

1. Everything you want to control is at one place. You dont have to use laptops or palms to tune.

2. It lets you progress from passive to active mode as you settle in with all the functions you control.

3. It has decent build and sound quality. It would give you about 60-70% of the sq that you would get with a hu+proces setup.

Down the line, once you are comfortable with all the functions and how they link up, you could swap it out for a diff hu+processor. It would also be the cheapest option to start with. There by allowing you to spend on tons of dynamat that you should use. How you install the speakers + sound deadening go a long way towards ensuring better sq as mac has mentioned.

arun1963

..... or a top end alpine

modmx

That rf3sixty.2 equalizer is a bit pricey, anything comparable that isnt $400

arun1963

yes there are, but most give xover controls over a 3 way network and l/r eq over 15-20 frequencies. Not sure if they give time alignment, which means you would have to look for a hu with time alignment........gets complicated.

I run the pio p-880 and am very happy with it. Ask mac what he recomends in Alpine and chose between the two.

HU + processor = $400-600
Alpine / Pio = $ 350-400

MacLeod

If youre wanting 6 channel, 31 band EQ youre gonna have to fork over some cash. $600 at least just for the processor. They dont make the H701 anymore which is my alltime favorite so my next pick would be an Alpine 9887 with its excellent crossover and time alignment features and then get an Audiocontrol DQS which is a digital, 6 channel, 31 band EQ.

But if youre not wanting competition level sound quality of just dont have that kind of money to spend, Id just get the 9855 and use the 5 band parametric EQ.

modmx

hate to keep bugging you guys, but im at a crucial point where I need to start purchasing my system.

Mac, whats your take on the ID IDQ 12v3 vs. the polk sr-124dvc. The idq's are alittle more pricey but i see nothing but great reviews on them

MacLeod

ID makes some pretty damn decent subs but I really love my SR12. I have ZERO eq'ing on this thing. Zip, zero, nada. I put it in a 1.25 ft3 box and it plays virtually ruler flat down to 25 Hz or so. All I did is set the sub level and the Polk engineers do the rest.

Works like a charm too. Will EASILY play the 21 Hz note on the MECA disc and the 18 Hz note on the IASCA disc.

arun1963

+1.

Had mentioned some good subs that I had heard and the IDQ is one of them. I will be upgrading my momo sub setup down the line and I know I'm going to go for the sr124dvc.

HU : Alpine / Pioneer----your decision
Fronts : SR 6500---closed
4ch Amp - PA 500.4

---

closed (bi-amp your front comps)
Sub : SR 124dvc---your decision if you want 1 or 2
Mono amp : You would need a mono if you decide to bi-amp your comps. Bi-amping is recommended but finally its your call.
Dynamat Extreme : get like 2 mega packs
Plus ofcourse the normal stuff like rca's, speaker and power cables, distribution block if ure running 2 amps, fuse etc etc.

Enjoy the shopping.

BTW who is going to do the actual install?

Mac / Cody and John are the installation experts. Make sure you get some info on this topic before you do the actual install. Proper installation can increase the sound quality significantly.

modmx

thanks for all the help along the way fellas, heres the final list. I will be ordering everything in the next day or 2:

HU - Nakamichi CD400 (plan on purchasing a RF 3sixty.2 in the near future)
Components - Polk SR6500
4 Channel - PA500.4 (will be Bi-Amping my components)
Subs - Dual IDQ12v3 (getting 2 ohm coils, guessing thats the right thing to do considering my amp will push out 1200 x 1 at 2 ohm) Heard nothing but amazing things about these new IDQ's. The box will be made according to the recommended specs given by Image Dynamics.
Mono Amp - Polk PA1200.1

2 mega packs of Dynamat
5lb bag of polyfill
Rest of the wiring and accessories


The installation will be done by a local guy that I know, has done a good job on some installs I've seen. Done some tough jobs with surprising efficiency. That and...hes charging me about 200 for the entire install (not including dynamatting). this is night and day compared to the 600-800 quotes I'm getting from other places


whadya think arun? any tips or concerns Mac?

arun1963

Choice looks good. This is a really good system in the making. Once you get the rf360.2 you will begin to hear the true potential of your setup. Congrats.

I hope the pollyfill is for the sub box and not the doors. When I was damping my doors I wanted to use pollyfill as an additional application but mac recomemded that I stay away from it. Even with the sub box, if its made to the right size your don't need much in there.

Try and install the mids with a bit of toe in, it would put the near side mid a bit more on axis, it also has another benefit which I can't recall right now. Mac would know by how many degrees to toe it in. Mount the tweets on the A pillars about 1/2 to 2/3 (about ear level) in a cross firing position. Left tweet pointing to right seat headrest and vice versa.This helps with the stage height and imaging bit.