Amplifier Tuning Guide (the basics)

[gwb72tii]

just to comment on all of the various write-ups from Stereoinstaller1, for those that are new to this website. Do yourself a huge favor and read through all of the stickies regarding installing and tuning a $500 killer stereo. Plus the DIY lukebox thread since Luke is no longer around building Luke boxes.
From someone that did this a few years ago, and am now going to install the same in my 535is, this system is killer. Absolutely worth your time and effort if you demand, as I do, high fidelity from your car stereo. I had this system in my '89 325i I sold and it was the best sound system I've ever had in the many cars I have owned.

FYI

[benz-tech]

One thing I would do though different is use test tones, it's much easier to hear distortion in a tone than music. Back in the day it wasn't as practical as you needed a special CD (autosound 2000 has some good one) but nowadays there are many programs you can download for free to make your own test tones. For the front and rear speakers I use a 1kHz tone at -5dB. That gives you some gain overlap, useful on quieter recordings.

+1 on using test tones to fine tune. After using Luke's awesome amp tuning guide I still had some sound quality issues. Plus, my sub had this horrible 40-50hz volume bump that overshadowed the rest of the bass frquencies. It turns out my amp has a bass boost that is tuneable. Now I have a nice flat response from 30 up. And im still working out all the buzzes from the interior. A free tone signal generator app is helping me fix all my issues .

[StereoInstaller1]

I thought I edited that...shit!

OK, will try to get to that soon, I think the edit is on the site maybe?

Fuck, I dunno know, I am up to my ass in busy!

Thanks again for all the kind words, fellas.

Luke

[dubdub]

I am certainly not an expert by any measure... just fumbled through my own systems over the years.

[vpilarrt]

That makes sense, dubdub.

[dubdub]

Am I missing something? In 2c you have the deck turned up to max. In 2d you say that the deck volume is now at the "reference" point. I don't see where you turn down the deck volume and how you determine the "reference" point.

I just had the same question when reading the guide, but figured I should read the whole thread before positing a question, and I stumbled across this post by another with the same question.

I've always done something close to the following - With the amp gain set low, play some music and turn up your receiver's volume until you hear the music distorting; then back off the volume until the music sounds clean again. Note or mark where the receiver's volume is. This setting is the maximum volume your receiver can go to and still play cleanly.

Not sure if Luke is blazing a new path here, or maybe we're just misreading something.

Thanks in advance, Team GAS.

[MPLFoster]

BUMP for a great write-up. Definitely a must for anyone with a luke-box. Still fine-tuning things but it just keeps getting better and better with this as a guide to follow. :up:

[E30Nova]

So I just tuned my amp using this guide over the weekend.

I'm kind of confused because my volume isn't really as loud as I'd expect. In fact, I have to turn the head unit up higher than without the amp to get roughly the same volume. And it's basically maxed out at that point.

I even tried upping the gains on the amp and it didn't give me much more volume.

I have a planet audio 1800.5 amp, alpine ida-x100, 4 Polk audio speakers (I forget the exact size/model), and a 12" bazooka tube.

Yeah, this isn't in an e30, but I figured you guys could help.

[dlmrun2002]

Back in the old days (daze) the head units only put out small levels of voltage so I use to run a preamp to the amp to get a higher voltage (plus a little eq from preamp). Amps seems to sound better with the preamp in line.

dlm ny country old school audio ads ph 15/ppi 4800.2/ 3x 8w6 dual voice coil jl subs

[StereoInstaller1]

It really depends on the output voltage of the head unit. My Pioneer DEH80 PRS outputs are rated at 5 volts. The average deck is rated at 2 volts. Even with the amp gains all the way down my system should play much louder than if I had a 2 volt output on the RCA's.

Pay attention here guys: his intent was not to say a 5V deck will make your system louder, he is saying that with the gains all the way down that a high-volt deck will play louder than a standard voltage deck.

Makes sense though, doesn't it? You are shoving more voltage in, of course it will be a bit louder at "zero".

This can also be an issue with some amps that are very sensitive, for example the McIntosh MC660, which reaches full output with only 1V of input...can't turn that thing "all the way down" unless it is driven by an iPod!

Luke

[dwvw]

It really depends on the output voltage of the head unit. My Pioneer DEH80 PRS outputs are rated at 5 volts. The average deck is rated at 2 volts. Even with the amp gains all the way down my system should play much louder than if I had a 2 volt output on the RCA's.

[Rmlr]

Reference Volume

Luke Can you shed some light on this? I am a bit confused as well

Am I missing something? In 2c you have the deck turned up to max. In 2d you say that the deck volume is now at the "reference" point. I don't see where you turn down the deck volume and how you determine the "reference" point.

[325ix]

I'm still working at tuning my system. The one thing that still is odd to me is that even with the gains all the way down, I still get sound, and not just faint sound. It is able to play music quite loud on no gain, but it does sound terrible. Do I have my deck amp on still?

[StereoInstaller1]

Did this yesterday and now my stereo sounds even better! Thanks Luke for helping out the community

You are so welcome! Glad to hear it helped, thats why I wrote this mess!

Did this today, now my e30 sounds as good as my e90 with premium sound!

Wait...what? If you have one of our boxes and a 5 channel amp, your E30 should destroy an E9X Premium system.

Glad to hear it helped!

Luke

[jottati]

Did this today, now my e30 sounds as good as my e90 with premium sound!