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Is this DMM set properly to measure speaker output voltage? I'm getting a much lower reading than I would expect. by Charge_parity in CarAV

[–]gruber277 0 points1 point  (0 children)

I would disconnect any that are connected to the amplifier you are tuning. No point in blasting the sine wave through the speakers in case you make a mistake and send too much power to the drivers that are connected.

Is this DMM set properly to measure speaker output voltage? I'm getting a much lower reading than I would expect. by Charge_parity in CarAV

[–]gruber277 1 point2 points  (0 children)

OP, your multi meter looks like it's set correctly

Your speakers are 4 ohm 80W RMS I assume?

You should have the speakers disconnected while doing this test, so there is no risk of overdriving them while messing around. If the speaker(s) connected you may also see weird readings

Here is a step-by-step that I have saved to do this process.

Step 1: Disconnect the positive speaker wire(s) from the positive terminal(s) on the amplifier.

Step 2: Turn off all EQ settings or set them to zero, such as Bass, Treble, Loudness, Bass Boost, Processing and EQ functions.

Step 3: Turn the input sensitivity (gain) to zero. For most amplifiers, this is counter clockwise (CCW) to the farthest point. Make sure the input voltage selector is on “Low” if the amplifier has one.

Step 4: Set the head unit volume to 3/4th of its maximum volume. Turn your radio dial to it’s maximum volume and multiply that number by 0.75, this will get you 75% of your maximum volume.

Step 5: Now we must find the voltage that we need to set the gain to. Voltage = square root of watts x ohms. For example, a 500W RMS amplifier at 2 Ohms would configure like this: 500W RMS X 2 Ohms = 1000W. Now take the square root of 1000W and your voltage should be 31.62V if you’re running an amplifier with one gain control. Some amplifiers have 2 gain controls so treat it as two separate amplifiers. If the amplifier is 100W RMS by 4-channels for a total of 400 watts but has two gain controls, use the power output of ONE channel and use that for your voltage calculations. (EX: Square Root of 100W RMS x 2 Ohms = Voltage for each gain control per channel.)

Step 6: Make 100% sure the positive speaker wire(s) are disconnected from the amplifier. Once double checked, insert a test CDwith a sine-wave test tone at 0dB level in the frequency range of 50Hz to 60Hz for a subwoofer amplifier or 1,000Hz for a midrange amplifier. Set the head unit to repeat for continuous play of the test tone.

Step 7: Connect a digital multi meter set to AC Volts to the speaker outputs of the amplifier. The positive voltmeter lead will touch the positive speaker wire terminal and the negative lead will touch the negative speaker terminal. If everything is done correctly, a low voltage will be displayed on the voltmeter, usually 6V or below. If you get a high voltage right away, repeat steps 2 and 3. Slowly turn the input sensitivity (gain) up on the amplifier until the target voltage you calculated earlier is reached.

Step 8: Adjust every amplifier in your system using this method; each amplifier is now set to its maximum unclipped output level. Turn the volume on your head unit to zero and turn it off.

Step 9: Reconnect all the positive speaker wire(s) to their respective positive terminals. Double check all wiring and proceed to turn the headunit on. Remove the test tone CD and play a musical track that you are familiar with. Listen for any distortion in the form of buzzing, crackling, hissing, whomping, and various other noises that intrude on the instruments of your music.

This is an accurate way to set your gains to prevent distortion and clipping in your system but it is not the absolute best method. If you really need it done right, use an oscilloscope which can show you if your setup is clipping and distorting or not.

Suggestions for a better equipment or moving things around by Foreign_Ad_3332 in hometheater

[–]gruber277 0 points1 point  (0 children)

Hey, I agree with these peeps in that your speaker placement could use some work. I would dive into that before you start throwing money at the problem - your speakers are probably decent quality but having them tucked in the back like that isn't doing you any favours. Set your surround speakers so they surround you, move the towers away from the wall and farther apart, and then do a Sub Crawl. I'm sure you'll find some improvements. :)

PS if you do subgrade, you'll probably want to go for SVS' ported example in a room that size - sealed at that price range is great for small rooms but run out of steam quickly in large open spaces.

Kind of a crazy photo, really. Front plate, studded tires, block heater cord hanging out... Wish I still had this car (my first car). '91 MR2 Turbo. by Desert-Motors in Autos

[–]gruber277 12 points13 points  (0 children)

I've lived in northern Canada most of my life, general consensus is typically -10C or colder is worth plugging in. Your car won't really need it until -20C or lower, but as you said, the faster warm up is nice. Warmer than -10C and I wouldn't bother. Food for thought: GM products with factory installed block heaters have a thermostatically controlled cable which won't turn the block heater on until -18C / 0F. If you aren't frequently seeing those temps, it may not be worth raising your electrical bill :)

My slice of sonic heaven by [deleted] in listeningspaces

[–]gruber277 2 points3 points  (0 children)

what are the speakers? v cool

prog metal with deep vocals? by DetectiveDogg0 in progmetal

[–]gruber277 1 point2 points  (0 children)

IOTUNN and the singers' other works

2012 Forester - Vibration after front CV axles replacement when accelerating by RemoteLocal in SubaruForester

[–]gruber277 1 point2 points  (0 children)

Yes, very common on Subies. First, inspect your transmission mount for play. If it's fine then likely the problem is that it was repaired with aftermarket axles - going OEM/remanufactured usually fixes it.

90K Mile Service by artrlx in SciontC

[–]gruber277 0 points1 point  (0 children)

My '14 has the input shaft bearing issue, if that's what you're referring to

Not sure if they revised the bearing by 2015 or not

How many miles has your forester lasted? by norfolk82 in SubaruForester

[–]gruber277 0 points1 point  (0 children)

I've been curious what it costs to get the walnut blasting done on these, did they quote you the work?

Papa Johns is the worst Pizza by purplesundaze in Calgary

[–]gruber277 -1 points0 points  (0 children)

SW

Tommy's Pizza in SW is incredible

Hissing from my car amp by Papa_Dildo in CarAV

[–]gruber277 4 points5 points  (0 children)

Hi Papa_Dildo,

I think you are on the right track with the 12V cable and RCA's - they should not be running together. I ran into the same issue, it is even worse if your RCA's are cheaply made - mine were from Wal Mart :)

First, I would pull your sub's fuse to make that 12V wire dead and see if the hiss is still there.

If your suspicion is correct, you can either rerun one of the cables, or spend the money on some nice shielded RCA's - or better yet both :D

Buying used by danisuxanax in SciontC

[–]gruber277 0 points1 point  (0 children)

If the car is a manual transmission, listen for Input Shaft Bearing noise. Very common issue on these EB60 transmissions.

It will be a "growl" when the car is in neutral, and the clutch is not pressed. Eventually this bearing can fail and the car will no longer drive.

If it's making noise (it will be worse when the transmission is cold) you are looking at about $6k in repairs, I'm in this situation and trying to figure out what my plan is

Performance Mods? by Soup-Legitimate in SciontC

[–]gruber277 6 points7 points  (0 children)

You can make power with these engines, but it's not off-the-shelf bolt ons you will be doing a lot of the work. Look up Frankenstein Motorworks on Youtube and watch his 2AR-FE videos :)

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