Help with gain adjustments

[shi_daniel]

Hello everybody!

 

I need some help with my sound system. Nowadays I have a simple config:

 

- HU Clarion NX702

4V Preout

 

- Pioneer GM-X904 Class A Amplifier:

150W x 2 (@14.4V, 4 ohms)

75W x 4 (@14.4V, 2 ohms)

120W x 2 (@12V, 4 ohms)

60W x 4 (@12V, 2 ohms)

Gain: 0.4V-2V

 

- Front Doors

2-way Infinity Kappa 60.11cs

Power Handling (Continuous/Peak): 90W / 270W

Impedance: 2 ohms

 

- Rear Doors

Stock Speakers connected to the HU (turned on only when there is someone in the back seat; most part of time are turned off)

 

- Subwoofer Rockford Fosgate (R1-1X10) (10")

200W RMS; 4 ohms

 

I've already read a lot about how to config gain in amplifiers, but I still have some doubts:

 

1) I see many people saying to match HU Preout with Amplifier gain. In this case, I should set 2V in my amplifier (its the minimum setting in my amplifier), since my HU Preout is 4V. If I do that, I don't have a good output from 2-way (rear stock speakers become much more louder than 2-way speakers) neither from Subwoofer. However, If I turn the amplifier gain up that feeds 2-way speakers (i.e to 1V), I can hear a hiss sound from 2-way at low volume and good sound level at high volume; HU level goes from 0 to 40 and I have an excellent output in 30 with 1V amplifier gain feeding 2-way speakers.

 

2) Bass is very weak even with armrest down (enclosure is positioned aligned with back seats with Sub facing rear car). I know Sedan trunks has much less SPL than hatchback (I've used this amplifier in a hatchback car - few years ago - and the bass was incredible good). I've tried turning amplifier gain at maximum (0.4V); even so, I don't have a great bass. I don't know if this setting can burn my Sub, but I don't realize any distortion at maximum amplifier gain level configured only for Subwoofer (2-way is feeded with 1V amplifier gain to have a good sound level, despite hiss sound at low volume)

 

I ask if I can have some problems with my sub and 2-way speakers, since I always see people saying to match amplifier Gain with HU Preout.

 

Is adding a second mono amplifier the only way to improve bass? I see many people from BMW forum complaining about lack of bass even with 12" Subwoofer and 500W Mono Amplifier. Then I don't want to spend more $$ if there is a risk to have a bad result.

 

Will I burn my Sub if I let amplifier gain at maximum (0.4V)? At maximum setting on sub channel I think bass is starting to be good and I can deal with that only if there is no risk to my Sub. I don't know why my Sub is not distortioning at maximum gain Amplifier setting (maybe my HU Preout is delivering only 0.5V @ 30 HU volume level...what do you think?)

 

I'll be waiting for your comments ;-)

 

Thanks,

Daniel

 

PS: Sorry for my bad english

[Stryder]

I've been in the midst of doing my car audio, and from what I've read countless times, everything says to leave your head unit at default settings, and only mess with the gain on the amp. I could be wrong, but I've read that many times.

[shi_daniel]

Hi Stryder!

 

I did that. All bass and treble from HU set to the midle. I just want to know if buying a new mono amp will improve bass, sice many BMW's owners complains about no bass even using a 500W mono amp.

 

Anyway, thanks for your help ;-)

[Stryder]

If you want the most bass, go to a audio shop and have them make a custom box for your trunk. The box makes the subwoofer, so any prefabbed boxes will sound bad/quiet compared to a custom built. A shop near my house estimated $300 for a box to be built and installed in my car. It would be tuned to whatever subs I chose, and the box is 3D modelled before install to assure best fit. If you already have the subs, I'd say $300 is fine.

 

Looking at your sub, I see it's in a tiny enclosure, there's the issue.

 

I suggest getting something like these if you want some loud bass at a cheap price: [ame=http://www.amazon.com/Rockford-Fosgate-P3D2-12-12-Inch-Subwoofer/dp/B004UFHXOM/ref=sr_1_1?ie=UTF8&qid=1432929605&sr=8-1&keywords=12%22+rockford+fosgate]Amazon.com: Rockford Fosgate P3D2-12 Punch P3 DVC 2 Ohm 12-Inch 600 Watts RMS 1200 Watts Peak Subwoofer: Car Electronics[/ame]

(2-ohm sub)

 

And the amp to compliment it (comes with wiring and bass control knob): [ame=http://www.amazon.com/Rockford-Fosgate-R500X1D-Amplifier-Remote/dp/B00N342BYS/ref=sr_1_1?ie=UTF8&qid=1432940720&sr=8-1&keywords=500W+mono]Amazon.com : Rockford Fosgate R500X1D 500W Mono D Car Amplifier + Remote + 4 Gauge Amp Kit : Car Electronics[/ame]

 

Sub would be underpowered by 100W, but the fact that you'd be adding a custom ported (or sealed) enclosure and a larger sub would make a world's difference.