Using an Oscilloscope to Set Your Gains for Around $50

Great, thank you. I was hoping to avoid having to find an appropriate adapter separately.

 

Ok. Here’s how the re-test going.
I know you supposed to turn the bass remote al the way up. So did.
Sw @ 1 : full hard clip. Amp gain 0. Radio volume 33/36.
Turn remote down to 2 o’clock: clipping went away. Amp gain 0.



Try 2.
Volume: 33/36
Sub lvl: 2
Remote knob unplugged.
Amp gain turn up to 9 O’clock before clipping



Plug in remote and clip right away. Remote turned all the way down.


so what do i do now? If i leave the remote plugged in, it can only stay turned down. If i give it a tiny turn, it will show clipping. i like having the remote to adjust on the fly. But at full turned down it is practically same as leaving it unplugged.

The cabin air volume in the sequoia is terrible with the factory sub box even with upgrade subwoofer. I feel like it doesnt have that punch im looking for.

what do you suggest i do next?
Set sub gain without running the remote knob?

running a test song that i like and with the above setting of no clipping. I can not hear any sub unless i start turning up the remote knob to pass 60%.

sounds terrible. I had put the front and rear speakers crossover all the way up on purpose so no bass would come through them and only let the sub do the bass. Barely hear it.
Probably need better sub box. Dont want to because there’s nothing available that can be “hidden” and out of sight like the factory location.
Im a little lost.
I can “tune” it by ear but i am very certain the amp is sending clip signal to the sub. I dont listen very loud. Normal volume is 7-10 out of 36. If im by myself, 11-13 out of 36.

 

Man that's pretty strange.
I'm not sure how those joying head units are built, but on other head units, usually you want the sw on the head unit to be at 0 or maybe +1, when you first said that it was at +9 I was like WOW.....

Does the level go into the negative or is 0 the lowest?

Really strange results with the bass knob, usually they just attenuate down from the setting you have it. It almost sounds like it's boosting it.

Do you have any pictures of the clipped curve?

 

Yeah. No idea. The second photo where the sine wave is square at the top and red numbers on the upper right corner. That’s clipping.
The remote knob def boost it. It’s almost as if the knob is a bass boost knob and not a normal attenuate knob. I can control the sub level for more or less volume from the headunit. It goes from 0-10. At 0 nothing is heard. So that is an attenuation there. But with the remote knob it will send it over to clip land. The way the headunit is setup you cant change the sub level on the fly like with the knob. You gotta go into setting, device, sounds, THEN subwoofer. There isn’t a shortcut either. Which is why i prefer the remote knob.
for now i just tune it by ear to my liking and remember to never turn up the volume to too high.

 

Not seeing any pictures. Did you post them?

 

Ok. I just re-edit to add the photos. Not sure why it didn’t show before.

 

Ok, i can see them now.

I'm kinda at a loss, I would say to ditch the s/w knob if it is somehow boosting the signal, but if it eliminates your bass then thats no good. Its just a bass knob that connects to the amp, not one of those inline rca ones?
I feel like there's some sort of a setting thats throwing the signal off.

Those voltages look really low to if they are connected to the amp.
I believe this picture was when i was setting the s/w gain on one of the amps. I'm getting around 27v

 

Yeah. I have no idea. Maybe it’s my oscope???Another thing also, i dont know if it matter, this radio sub out is only a single (1) rca plug. I have to use a y splitter to have 2 channels for the amp.

 

Hmmm.....i'm not quite sure.....both sides of the splitter should be seeing the same voltage i believe.

 

We definitely know these type of radio were not built with quality audio in mind. So, who knows?

 

Here's my findings using your recommended tools and method on a stock non-JBL head unit (2019 crew max). I used some JL Audio files on a usb stick, and measured before the stock amplifier input under the passenger seat.

40Hz, 0 db: 55 (max volume before clipping)
1 kHz, 0 db: 51
4 kHz, 0 db: 51

At the moment I'm using a JL Audio's Fix 82, 250/1 v2, and their ported micro sub box with the 6W3v3 behind the rear seats, set at about 150 watts. Earlier this year I assumed the max volume before clipping was 46 just by ear, and I haven't re-set my amp gain because its already at minimum. The plan is to add another sub next year and re-tune the system then.

 

What's the max # the head unit will go to?

 

The max volume is actually "MAX", one tick up from 62.

 

So you can safely go to 51of62. Not too bad.

 

On JL Audio's site they say to set gains at 3/4 head unit volume if you don't know when it clips. That turns out to be 46, where I thought I heard some reductions above. I'll play some music up to 52 and 55 now and then and it still sounds good. Its good to know my sub isn't clipping, I'm not worried about the stock speakers since they'll be replaced down the road anyways.

 

I can't handle the volume much above 30 in the standard cab with my setup. Here come the old person jokes...

 

What? My hearing has taken a significant turn for the worse.

 

Sounds like you have experience with Helix DSP's?

I haven't had the time to begin the install other than pull a power cable into the cab and label the 2 plugs that bypass the factory amp under the passenger seat.


I've looked at the original Helix version 4 software attached to my Helix M4DSP and it's nowhere as simple to manipulate as the JL TWK was running in the last system and sold.

In hindsight I would have kept the JL and used a simple audio control unit to go from high level to low output in the TWK and then 5 channel amp.


A little learning curve in in order and I'm only looking to initially program for front and rear door speakers(2 way Hertz) with an output for a single JL 10" sub and tech 12volt box I have ready to go.

Hoping I can do a simple setup using distance for time alignment and call it good. The local shop that sold me the M4DSP lost their Helix tuning guy and expect me to jump through hoops to have this expensive brick programmed.


Once there's more time I'll consider installing separates in the front and a little dynamat which will be more than enough for my expectations.

Anything would be an upgrade over the factory non JBL system.

 

@Danimal86 How would one do this when keeping the oem H/U ('23 Tundra)? Will be using DSP

 

I dont see any reason why you couldn't folow the same process with the factory head unit. The projecess would be mostly the same, except you would be using speaker level outputs (not rca's).

What dsp are you using? I also have a guide on how to use REW and a calibrated microphone to tune your dsp.

If you are going down the rabbit hole of DSP with active crossovers, i would highly recomend replacing the factory head unit. I spent a lot of money and a lot of time trying to keep the factory head unit, it will handicap you. Many people told me the same this same thing, but i really wanted to keep the stock look....i finally gave up and replaced it with a

$1,000 kenwood dmx1037s 10.1" high definition car stereo receiver with capacitive touch panel

kenwood dmx1037s and wow, what a great head unit. Clean power and great features.

 

Thank you! I figured since the oem isnt pushing full range to every channel it wouldnt work. Will five it a try. Not really an option to replace OEM. I have that giant 14" screen. Would have to refab the entire dash to put in aftermarket.