Help needed tuning a Class D monoblock AMP

[wifiuk]

wondering if someone can lend a hand ...

I have a bassface DB 1.2 Class D amp, 2000W RMS / 850W if i remember correctly.

I have a Pioneer AVH-X5500BT headunit.

I have a Bassface 1300W / 650RMS sub

Now i know that the sub is less powerful that the amp, but the amp was originally for a more powerful sub that blew //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

I could do with a hand tuning this setup.

At the moment its all working and the EQ on the headunit is set to flat, the HPF on the headunit is off.

It sounds terrible, i have to have the radio loud to get decent bass...

here is a screenshot ( not my setup, just an example ) mine are all set to flat

On the amp i have the following dials

could do with a hand getting it sound better, any advice?

Click to read more...

 

[Jeffdachef 5,000+ posts]

look up a video on youtube on how to set your gains with a digital multi-meter.

Should read this if you want in full detail.

http://www.caraudio.com/forums/car-audio-reference-database/532425-new-car-audio-read-first.html

but if your a lazy bum here's how to set it by ear.

Keep head unit settings at flat, bass/bass boost off, subwoofer level max. turn your head unit volume to the loudest you normally listen to usually 75-85% with pioneer head units. get a 50 hz -6 db tone put it on a CD, turn all gains(level knob on amp) and bass boost off on amp, subsonic minimum, low pass maximum. Play the CD at the volume level you already set it, then slowly turn the gain up until you hear the sound/tone of the bass actually changing instead of getting louder. Then back it off a bit and your done. Then adjust your subsonic filter up close the point where your subwoofer enclosure is tuned to and put low pass filter down to 80. Do not use bass boost at all.

If your subs are normally mounted then keep phase at 0 degrees, if they are inverted then go 180.

If your gains are going past 75% and your not happy with the loudness then that just means you need more power and efficiency with a better quality amp. Sorry to break it to you but that amp you have is 600 rms at best with two 30 amp fuses. You probably blew your stronger sub from bad amplifier settings clipping it to hell not from the amp being too strong.

 

[wifiuk]

so i have been doing research on the sub specs too so far have come up with this

SUB VALUES to be dialled into the AMP

Subsonic = 35Hz ( middle dial position )

LPF = 80 - 100Hz Crossover ( middle dial position )

Phase = 0 ( all the way to the left dial position )

BASS BOOST = 0 ( all the way to the left dial position )

LEVEL / GAIN on amp = ?

( 4 Oams ) currently researching the DMM way ...

one question i do have is once i have set this up at the amp with the EQ = flat ... how do i then dial in the EQ settings on the HEADUNIT to make the voice and mids sound better without adding bassboost / adding extra bass from the EQ settings

What about high pass filter, do i need to adjust that on the HU?

 

[calebkhill 10+ year member]

Those settings don't look flat to me...

What kind and how many speakers are in your car...

 

[wifiuk]

that was an example screenshot from the internet, mine are flat ( but it just sounds poop flat )

i have a UK ford focus with standard speakers there are 8 of them 4 in the front and 4 in the rear, tweeters mids and the normal speaker

 

[calebkhill 10+ year member]

Can you explain that differently, I'm sorry just fdon't understand.

8 speakers total..

4 in front, 4 in back?

Can you tell what size speakers, how many, and what locations.

Also, these are all stock speakers running of the head unit?

 

[wifiuk]

these are all stock speakers running from the headunit, nothing after market but they are separated, so 2 tweeters in the A pillars and back doors

and 4 mids and bassier speakers in lower front and rear doors ( factory standard )

also i have the multimeter on the left below

i have tried all the settings, not sure which one to be using to tune the gain on the AMP.

but when running the 50Hz test tone with 0db on my system, i cant seem to see any changes to the voltage when i turn the gain up or down ...

also the speakers in the car are spitting out the 50Hz tone too .... not sure how to use the HPF to stop them playing it ..

what am i doing wrong?

 

[calebkhill 10+ year member]

Ok, first, check out the sticky on gain setting using a dmm...Do that first..

Then, set the sub lpf on your hu to 80hz

Set hpf to 80hz.

You only want to cut eq to make it sound better, bnot boost.

Also, try using your fader to fade more to the front and to cut the rears some, no need for rears to play at max volume.

I'd also consider disconnecting the rear tweeters.

 

[orphe 10+ year member]

the absolute best way is to use an oscilloscope. and a 40 - 60 hz test tone.

 

[wifiuk]

yeah dont have a oscilloscope unless i do a robbery on a local college science department or something , lol

i have a 50Hz tone track on my USB stick, i have no LPF on headunit, only have a HPF - thats has OFF, 50Hz, 80Hz, 100 Hz, 250Hz something like that ....

I have looked at my DMM tutorials, none of them are like the one i have, just need to know the correct symbol to put it on...

 

[calebkhill 10+ year member]

Does the head unit have a subwoofer menu. The lpf should be there

 

[wifiuk]

it says subwoofer on or off, and actually yes i think it has a submenu in there ...

also my AMP has a remote bass knob, which is very handy for when the kids get in the car i can turn the bass off, but does this mean i have to have the bass boost on at the amp to be able to use it?

 

[calebkhill 10+ year member]

Leave that bass boost alone. The knob should work regardless. Set those crossover settings (lpf, hpf) and experiment with cutting eq, also experiment with fading to the front.

 

[wifiuk]

so looking in the PDF online manual

the LPF on the headunit has the followin

OFF, 50hz-63Hz-80Hz-100Hz-125Hz

And in the HPF i have the same options,

My sub can take range upto 100Hz according to the specs.

So you think i should set these both to 80Hz

on the EQ on the HU, if i leave the range thats 80Hz and below on the flat line, that wont add any bass boost on the sub due to the LPF on the HU? but i can then increase the vocal and mid range on the EQ?

 

[calebkhill 10+ year member]

Right, set both to 80hz.

And right, any eq 80 below will affect subs due to lpf, anything above 80 will affect mids/tweets due to hpf.

But remember, try to refrain from boosting eq..... Only make cuts... Boost with volume, and correct with eq cuts..

Try and stay at 85% head unit volume.

And fade to the front. Your rears sounding off back there is complicating your overall sound.

 

---------- Post added at 09:47 AM ---------- Previous post was at 09:47 AM ----------

 

And I'd disconnect those rear tweets asap