Gains with a DMM

[ca90ss]

2/3rds volume? and what if your HU doesn't clip at all? what if it clips before 2/3rds? or just past it and now you've limited your system. and then throw in a DSP and your method really goes out the window.

Can't say I've ever tested a hu that started clipping at 2/3 volume, all of the ones I've tested didn't clip until the last couple clicks on the volume knob or not at all. Setting them at around 2/3 leaves room to go higher for music that is recorded at lower levels.

[captainobvious]

Also, I see WAY too many people set a system up so that the amps all clip at the same point. This will lead to a rather unbalanced sounding system as the HF components will generally have a much higher sensitivity than the LF components. In a passive crossover, all those resistors you see, are generally used to pad that tweet down so the woofer can keep up with it. Granted, some are there for impedance correction, but most are used for padding in some way, shape, or form.

Granted, but this is just for amplifier optimization/gain overlap setup, right? You're still adjusting (down) output sensitivity on the individual DSP outputs for those drivers before they hit the amp to adjust system balance prior, right?

[captainobvious]

Can't say I've ever tested a hu that started clipping at 2/3 volume, all of the ones I've tested didn't clip until the last couple clicks on the volume knob or not at all. Setting them at around 2/3 leaves room to go higher for music that is recorded at lower levels.

You'd be surprised at what I've found.

It's important to test *each* output and in the passband it will be playing as not all of the outputs will clip at the same output nor the same frequency. Even on "higher end" units like the P99RS I've found this to be the case. I attribute this to the part tolerances used in manufacturing.

[TheDavel]

My HU clips at 51.4% of max volume. That is an actual figure... Knowing this allows me to maximize use of my DSP.

[Strakele]

My HU clips at 51.4% of max volume. That is an actual figure... Knowing this allows me to maximize use of my DSP.

Good lord. Is that a factory HU you're integrating with? Or an aftermarket unit?

[chad]

Good lord. Is that a factory HU you're integrating with? Or an aftermarket unit?

no doubt

How is that thing being loaded?

[chad]

Granted, but this is just for amplifier optimization/gain overlap setup, right? You're still adjusting (down) output sensitivity on the individual DSP outputs for those drivers before they hit the amp to adjust system balance prior, right?

Why would you pull back on the DSP outputs and not the amp outputs? 2 reasons I can see not to:

1 signal to noise ratio, trim those amps back
2 you only have so many bits in the digital domain, use them all.

I've seen one instance to have a reason to have amp inputs just pinned, literally pinned.. To keep some jackwad from turning them up after the DSP is locked.

[TheDavel]

Good lord. Is that a factory HU you're integrating with? Or an aftermarket unit?

it's the factory VW navigation unit, no external amp.

no doubt

How is that thing being loaded?

We tested it with a DMM and an o-scope before integrating the DSP. Signal was terrible and it was clipping like hell at 18 and maxes out at 35. Bad apple?

[61ragtop]

Well I am going to try and make this mini speaker to set the gains. I don't have Radioshack in Canada but will try and see if I can find a similar item. I found all the instructions on the rockford fosgate site.....

http://rftech.custhelp.com/app/answe...stortion-meter

Lets just hope I can find a mini speaker like the one from RS!

[pocket5s]

Well I am going to try and make this mini speaker to set the gains. I don't have Radioshack in Canada but will try and see if I can find a similar item. I found all the instructions on the rockford fosgate site.....

http://rftech.custhelp.com/app/answe...stortion-meter

Lets just hope I can find a mini speaker like the one from RS!

Great find! I'm just going to start linking to that lol. The only thing different that I saw from the "kit" that mark uses is he put his voltage divider into a small enclosure with RCA inputs/outputs on it instead of putting the resistors inline on the harness. Both end up at the same goal though.