Proper Amp setup, anybody?

[tibimakai]

I have installed my Kenwood nav, new door speakers and two amps. One for the door speakers and one for a subwoofer. They are Polk Audio PA660.4 and PA880 amps.
I'm trying to learn on how to properly set them up, but I could not fine a good example or video anywhere on the net. Some of them are contradictory.
One example, some say that the stereo EQ has to be set up, as you would listen to the stereo, some say that everything has to be flat and off.
I have even an oscilloscope, to do it right.
I have verified my stereos output, with the scope and a 1Khz signal made by myself on the PC using Audicity. I'm getting, no clipping at the maximum volume of 35. It's an Kenwood Excelon unit, most likely that is why.
I'm not really sure, if that sine wave made by me on my PC, is right or not. Amplitude is 1.
Why I question myself is, because when I hook up the amp to the stereo and look at the speaker output of the amp, I bare open up the gain and it's already starts clipping.
The amp's sensitivity is .250mv to 8V. The Kenwood's output is 5V. In my opinion, I should be able, to adjust the gain somewhere 3/4 of the way, no?
I don't know, how should I adjust the amp, for this calibration.
Any help would be appreciated.

 

[V8toilet]

I used a volt meter to set my gains. Use this link, http://www.glasswolf.net/papers/dmmgain.html I'm too lazy to type it all.

I used the 1000 hz test tone for my 4 channel amp and a 30 hz test tone for my subwoofer amp.
http://www.ronelmm.com/tones/

Make sure the output from the source unit is as high as it will go. I have a Audio Controls DQ-61 set to 6 volts. The higher it is the better the signal to noise ratio will be. You will need a volt meter that can read AC voltage.

 

[tibimakai]

Thank you.
Actually I have followed those sites, but I have used my own tones. I will try with those then.
My sub is capable of 24Hz-200Hz(JL Audio 10TW3-D4). Which file should I use, 30Hz is fine, or should I go with 24Hz?
My stereo is maxed out when I'm calibrating.
I have a 100Mhz Rigol oscilloscope and a Fluke 87-V meter.
- cut out the MDF to cover my spare wheel and also cut out the hole for the sub. My spare wheel, is the box. No fiberglass.
- cut out a 6" rubber seal and placed it over the wheel holes.
- machined a 6" round aluminum plate, to cover the rubber seal and bolted it down, with a hex head screw for better clearance.
It's all sealed properly, I have even tested it with water and there it was no leak at all.
I have just placed the speaker in the hole, without bolting anything down and it's already hitting hard, with gain at 0, boost at 0.
I need to calibrate the sub amp(I may recheck again the 4 channel amp) and finish up the sub "enclosure".

 

[squibcakes]

Hi Mate,

You've been working on this install for a while ;-) but anyway at least you have got to this stage.

Always set HU treble, bass eq etc to Flat when adjusting amps. I use a 0db 1kHz test tone for mid range/tweeters and 50hz for Sub. There are many sites with these samples.

I found using an oscilloscope far better then using an rms voltmeter. With no speakers connected to amps connect oscilloscope to output of HU. Crank up the HU volume until it clips. This is the max volume you can ever run your HU. My CX5 HU volume was 47 max. Don't forget oscilloscope measure pk to pk and you want rms voltage.

I would set your pre out voltage to 4.0V as this gives you more volume knob range. A higher voltage means you are getting louder with less volume knob adjustment. I'm using a pac audio line convertor.

Then connect oscilloscope to front speaker outputs (no speakers), turn amp gain right down. Play the 1Khz tone, set HU volume to max from above. Slowly increase the amp gain until you see it clip. You can calculate the rms voltage form the oscilloscope which should be very close to what manual recommends for output voltage. I'm assuming you are bridging the amp to get the full 150w for the fronts (which is what I did on my JL amp). Once you know the voltage and your speaker resistance you should also be able to do a quick calc and confirm you are achieving your 150W.

Then do the same for the sub amp but play the 50Hz tone. Make sure that any remote volume knobs are at max.

Download the JL audio app and test tones. This app will measure the polarity of front speakers and sub. This will ensure none of your speakers are out of phase which esp hard to hear on the mid range. If your sub is rear firing you will most likely have to reverse the polarity.

The CX5's front door cavities are crap even with dynamat fitted- when driving full range audio to the doors you will get muddy bass. so you need to set the crossover points correctly.

I found through trial and error the best eq is 50Hz cross over on the sub, 100Hz on the front doors with a 24dB roll off. This will ensure both speakers cover the 50-100Hz gap.

Of course your speakers tuning will differ to mine but that should give you a good base to start from.

Ps where are the pics?

Cheers
Squib

 

[tibimakai]

I have replaced the speakers a couple of months ago, then I stopped working on the car. Now, I have started again and I hope that I will finish it too.
In principle that is how I did everything, except the sub amp, which I haven't calibrated yet at all.
My problem is the little details, like how do I setup the switches and pots on the amps.
How would I set my output voltage, I don't see any adjustments for that. I'm guessing, you can do that, with the Pac adapter, right?
My maximum signal from the stereo it's clean, there is no clipping.
I will make the calculation and double check my readings, with the scope. Good point.
I did not bridge the amp, I'm using it as a four separate channel amp. Should I bridge it?
I have not measured the speakers resistance, specially at the front where are connected the 3.5"s also. They are connected in parallel to the door speakers?
Which JL Audio app? I'm not familiar with that and how would I use that?
Could you please, elaborate on this one? "If your sub is rear firing you will most likely have to reverse the polarity." My speaker points upward, it sits on the spare wheel.
There are two crossovers, one on the amp and one on the stereo. How would I adjust each of them?
The door speakers lowest range is 53Hz.
http://www.crutchfield.com/S-O4hhqrSrdxs/p_108P6500CS/Infinity-Primus-PR6500cs.html
Dash 3.5" speakers:
http://www.crutchfield.com/S-i3K8No111n2/p_107DB351/Polk-Audio-db351.html
Subwoofer:
http://www.crutchfield.com/p_13610TW3/JL-Audio-10TW3-D4.html
4 channel amp:
http://www.polkaudio.com/pa6604/d/1164
Sub amp:
http://www.polkaudio.com/pa880/d/1165
Here is a picture when I was adjusting the four channel amp:
http://www.mazdas247.com/forum/attachment.php?attachmentid=208901&d=1412488388
http://www.mazdas247.com/forum/attachment.php?attachmentid=208794&d=1411879692
http://www.mazdas247.com/forum/attachment.php?attachmentid=208795&d=1411879692
Here is the sub amp installed:
http://www.mazdas247.com/forum/attachment.php?attachmentid=208168&d=1405960171
Thank you for your help, it's much appreciated.

 

[squibcakes]

On the 4xamp set both crossover switches to HPF.
Set the gain pot as per above instructions.
Set the cross over freq to 100hz.
Set the bass boost pot to 0 dB.

I've connected line level outputs from the hu via the pac loc then to the amp. I had a bit of noise floor hiss so by adding this I was able to adjust the voltage to entirely remove the hiss. I'm not sure if your hu can adjust the pre out voltage but don't sweat if you can't.

Since you are driving front and rear speakers than you wouldn't bridge the amp, however...

I think having the dash speakers plus the components is over kill unless you plan on not fitting the infinity tweeters but then u have a power miss match between the two. If you insist on fitting all those speakers up front then I think the proper way is to fit a 3 way crossover network to keep the amp happy. More expense for little result.

Personally I would drop the dash speakers (perhaps mount them in the rear a frames) bridge the 4xchannel amp and give the infinities everything. Mount the infinity tweeters in the dash. Run the rear door speakers off the Hu

The Jl audio app is in the iTunes store.

You will know if the sub is rev polarity when you increase the bass volume the overall bass in the car will actually go soft (out of phase with front speakers) then will go loud again.

Normally you would only adjust cross overs in either the hu or the amp not both. I would do it in the amps.

 

[tibimakai]

OK, I have calibrated my sub amp, but unfortunately, my "box" it's not done yet, to be able to hear it.
Here are some pictures:

 

[tibimakai]

OK, I'm almost done with the sub install.
I need to get some poly-fill and some screws, to install the speaker and wire connector. I may make a rubber gasket for the connector.
In have managed to cut a decent circle with the jigsaw. The speaker is almost tight in that hole.
Soldered all the wires and wire ends.
Used two straps, to tighten the board against the spare wheel.
I still have to cut pieces of 2 x 4 and make a connection between them, to stay in place. I will have to glue some of them, to the board also.
Most likely, tomorrow it will be done.

 

[tibimakai]

Another picture:

 

[Chris_Top_Her]

I gotta say, that looks like an Army job lol, but I know you put a lot of work into it. Good work.

 

[tibimakai]

It wasn't a lot of work, just cutting out that board.
This is the only thing that I could do.
I don't want to give up the spare wheel, and I need the trunk area.

 

[squibcakes]

Gee you wouldn't even know there is a sub mounted under the floor board. I just wonder though if it would sound better if you made a new floor board with speaker grill in it to help the sub radiate better. I guess when you turn it on see how it sounds covered / uncovered.

Have you done any volume calculations for for the sub and spare wheel to ensure you get the best out of it? Any other sealing between the Tyre and wooden mount?

 

[tibimakai]

I did some calculations with water and there is enough space. It's enough up to the lip of the wheel, so up to the top of the tire it's even more room then I need.
It sounds great, no need to change anything. Subfoofer level is at 0 at the stereo, no bass boost at the amp.
The floor is 2" higher now, because I had to add those 2x4s, since the speaker is 2" from the mounting surface to the top of the grill, a bit less without grill. I also have the 3/4" MDF.
There is nothing else between the tire and MDF.
MDF is super smooth and the tire is rubber, there is a very good seal between them. I have tightened it very-very well.
Initially, I had planned to drill some holes in the spare wheel and tap them, then make the same holes in the MDF, then use some threaded rods, which would be between the MDF and the spare wheel. On top use same nuts with washers.
But first, I said to try it out this way and it's working great.
I could add more bass, from the stereo and the amp as well if needed. I don't have the remote knob, but I don't need it anyway. I have set it and I won't adjust it any more.
I won't cover it with hat gray material, because this way it seals better and nobody will see it anyway.
The settings should be this way?
-speakers HPF crossover set to 100Hz(53Hz-is the lowest)
-subwoofer LPF crossover set to 120Hz(24Hz is the lowest and 200Hz is the highest)

 

[squibcakes]

ok I understand now.

As for tuning, you have to set it to some baseline values and listen for a few days and then tweak a bit and listen etc and in time you will know what sounds good and what sounds yuck. That's why I think it is a good idea to have remote gain for the subwoofer. You will find that some music sources naturally have lower levels of bass and and needs to be turned right up. What's a few more dollars?

The way the cross overs works is this:

The mid range door speakers (4 channel amp) should be tuned to around 100hz. Set it to hPF mode (pass all frequency above 100 Hz). At frequencies bellow this they will be faded down 12db per octave.

The subwoofer (mono amp) should be tuned to around 50hz. Set it to LPF.(pass all frequency bellow 50 Hz). At frequencies above 50hz they will be faded up at 12 db per octave.

Contrary to what you might expect , both speakers will be playing the frequency range between 50- 100 Hz so there is no hole in that frequency range they will blend into each other's cross over frequency.

I actually prefer 24db per octave for faster roll off for crisper response between the two sound stages.

Your door speakers will actually sound better taking away the bass duties and allowing them to play midrange.

Try some different combos of crossover.. 80 Hz / 40 hz. Or 90 hz / 45 hz or 60 hz / 120 hz....

 

[tibimakai]

Thanks for the pointers.
I don't have all these settings in the stereo. For example, the sub has only LPF, the HPF I have set it in the amp to 50Hz, which is the minimum.

 

[squibcakes]

This is all done on the amps not the stereo. Stereo is only for volume control.

The hPF should be set for 100hz not 50hz. This is done on the amp feeding the doors Speakers.

 

[tibimakai]

Some people say, that the amp should just pass through what comes from the stereo and all the adjustments should be done on the stereo.
This is my problem, everybody says something else and it is so confusing. It's very hard, to find a good source of information.

 

[squibcakes]

You can go either way but generally not both at same time. I guess you have to ask which of the two will provide better cross over selection the amp or the HU? Try both ways and decide for your self.

High end systems use flat response out of HU (don't use bass, treble or even graphic equalizer settings), they then use a parametric EQ system between the HU and the amp.

 

[V8toilet]

You can go either way but generally not both at same time. I guess you have to ask which of the two will provide better cross over selection the amp or the HU? Try both ways and decide for your self.

High end systems use flat response out of HU (don't use bass, treble or even graphic equalizer settings), they then use a parametric EQ system between the HU and the amp.

What he said, tibimakai there are no two systems that are tuned the same because of different components, car, and personal preferences. You'll have to experiment with the settings yourself and find what you like. I'd have to look but on mine I have the HPF set in the 60 htz range for my door speakers (front and rear are slightly different) and the sub LPF set at 80 htz with a 18 db octave. It took me hours of slight tweaks to get mine to where I like it over a few days.

 

[tibimakai]

I understand that, but there are so many adjustments and I try to understand what I'm suppose to adjust.
I have adjustments in the stereo, on both amps, specially crossover adjustments.
In the next couple of days, I will keep playing with these settings, until I'm satisfied.
I can definitely shake the whole car. I don't even dare, maxing out the settings.
This little JL Audio sub, hits like crazy. I did not expect that.
I can recommend for everybody this speaker, it's not cheap, but it's worth it if the space is tight.
I have managed to get this on CL-Orange county CA, brand new for $200. There is somebody selling these and others.