Issue setting gains with DMM?

[Sguirrelfeather]

I don't think I can have a signature yet (newb), so here's my setup:

2004 Ford Excursion

JVC KW-R910BT head unit

JBL GTO-5ez amp running 1 sub and front/rear door speakers

500W to sub @2 Ohm, 75W to speakers (RMS)

JBL GTO-3ez amp running another sub and the rear passenger speakers

500W to sub @2 Ohm, 75W to speakers (RMS)

2 x 10" JBL GTO1014D subs in sealed enclosure (1 box, 2 separate compartments) between front seats

350W RMS subs...I knew they were below my amp's rating, but i got a deal so why not. lol

6 x JBL GTO 509C component speakers - 5 1/4 mid, 3/4 tweet using included x-overs

75W RMS

So, my issue/question.... When I first put this in, I tried doing the setting gains by ear thing. That was a no-go because I have some hearing loss due to an explosion, so I decided to try to the included setup CD that came with the amps. Sounded great, never heard any clipping or distortion (except for a couple songs I learned do NOT need to be played loud or else it will eat the sub surrounds), etc. Well, after lurking in here for a couple months, I decided I would give using a DMM a try when setting my gains.

I used the 50Hz and 1kHz tones from Realm of Excursion which are supposed to be 0dB tones. Did everything the tutorials said....disconnected positive leads, made sure amp gain is on low (which I needed to set it to med because it was just about maxxed at the minimum gain setting), etc etc. I did the calculation for proper voltage to check for, double checked, set it, made sure both subs were as close as possible to matching, mids/highs set to match, and so on. Turned off, hooked speakers back up, turned on.....and got a huge disappointment. Honestly, the stock system was louder. Yes, the new equipment sounds infinitely better, but I could easily talk over it.

I decided to check the voltage while a really "heavy" song played at the max volume. On the subs it maxxed around 14V when the ridiculous amount of bass hit. Though at that volume, it was more like smooth jazz bass. lol I then used the setup CD and set it back the way it was before. I checked voltages on that same song and it was about perfect...at the volume I am comfortable playing that song at without fear of destroying things, it would peak, momentarily of course, at ~32V, just above the 31.62 I set the sine wave to.

For the record, I played the song from my phone using bluetooth, the test tone was played through my phone, and the song was downloaded off Google Play Music, so it wasn't a low quality/low volume copy. Any ideas? Did I do something wrong? Should I have used a different test tone?

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[wew lad 5,000+ posts]

you're better off setting your sub amp with a -6db tone and your mid/highs amps with a 0db tone, @Jeffdachef looked at some music and told me about this a while back, most of the low end wont reach the 0db level while the higher frequencies do regularly.

some music you listen to will require a higher gain than other music, i wouldnt be able to listen to my subs at the level i like if i couldnt adjust the output of my sub based on what im listening to. i regularly go from 5 to 8 on my headunit depending on what im listening to. a lot of it has to do with listening for the sub stop getting louder and learning when to back off

ill make your life easier, if you regularly listen to bluetooth on your phone through your headunit and use android, download frequency generator. you can choose any frequency and output level without needing to download individual tracks

 

[Jeffdachef 5,000+ posts]

I'd set the gain with the sub level at 0 to -3 and raise it up accordingly with the music you listen to.

Lets say you set the gain at -3 sub level on the head unit. Bass boosted and chopped/screwed songs can be played with the -3 sub level. hip hop, rap, Dub step, EDM can be at +1 or +2, rock, jazz, blues and metal can be at + 6 sub level. The sub level in and of itself is basically a gain knob meant for fine tuning adjustments so you dont have to go back to the amp and reset sh*t over and over.

Thats just an example of what you can do. The numbers and values will all change since your setup is different.

 

[350zspl 10+ year member]

you could try turning off any bass enhancers on your radio , decrease any bass knobs to lowest settings

set your amps to match the voltage output of your head unit

this is a starting point and you can increase or retard from there

never used a dmm or a test tone

have not blown a speaker in my life

been doing it this way for the past 30 years

 

[dev199505]

For the subs you could do the nose test if you start smelling them time to turn them down

Sent from my LGMS330 using Tapatalk

 

[Sguirrelfeather]

For the subs you could do the nose test if you start smelling them time to turn them down

Well, while that might work, it sure doesn't sound like a good idea. lol!

Thanks for the suggestions guys. I'll give those methods a shot and see how things go. I've got a friend with an o-scope. Maybe one day I'll see if I can borrow it and give that method a try.

 

[ummduh 10+ year member]

For the subs you could do the nose test if you start smelling them time to turn them down
Sent from my LGMS330 using Tapatalk

I smell my sub all the time :sadlol: Cheap subs s u c k..

Not being able to write out that word is just as s u c k y.

I tried the DMM method, and had the same results. Worked wonderfully on like 2, maybe 3 songs, but everything else was woefully under performing. I'm just doing the most despised CA method of using the gain as a volume knob now, since I don't have any equipment I really care about. Gain on the amp up to the max I'd want it at for those couple songs that worked out, and a remote gain knob on the dash to go up or down from there. I hate trying to get into the sub control menu on my h/u, nobody has a h/u with direct access buttons anymore.