so i went to spl show and wanted to see what my two sq hds200 dual 2ohm that is wired for a 2ohm load and even checked them with d.m.m and shows 2.1ohms but my mtx thunder 1501d older style no elite suppose to do 1500wrms@2ohms with 14.4volts has 2gauge welding wire and at the car audio show it only clamped 844watts. Im wondering why is this and is there something im  missing here and how to fix this to get my wattage up because my spl score in my 00 s10 ext cab was only 142.3 on dash http://www.termpro.com/asp/officialevent.asp?EventID=15579&Method=1000 name is david downs i entered the hardcore truck so i could have door open driver side and then unlimited car truck 0-2500w sealed dash was 136.4db. Help me please. I have only one battery and a ad244 alternator 145amp with all manual windows/locks blah blah

Did you measure impedance while playing, or while resting?

How did you test? What frequency, sign wave, music, how where you playing it when you clamped the 800?  

Well for one, with your electrical I'm guessing you're not getting a full 14.4 volts for the amplifier to operate at max power. Just an observation of course.

And for two, pics of your setup would help to see if your enclosure is optimized for the maximum resonance frequency. 

FYI, door open with mic in the kick panel is not a legal reading for testing. I would test and tune with windows up, doors closed, and mic on the dash.

Hope this helps !!! Good Luck 

14 minutes ago, Randal Johnson said:

Well for one, with your electrical I'm guessing you're not getting a full 14.4 volts for the amplifier to operate at max power. Just an observation of course.

And for two, pics of your setup would help to see if your enclosure is optimized for the maximum resonance frequency. 

FYI, door open with mic in the kick panel is not a legal reading for testing. I would test and tune with windows up, doors closed, and mic on the dash.

Hope this helps !!! Good Luck 

Doesn't mid west rules allow for the windows to be cracked or doors. Could have swore I seen that some where. 

You pay money, they will throw the mic in the port. Doesn't mean it's legal.

A clamp test isn't so relevant, don't be too excited about the results.

1 hour ago, Randal Johnson said:

You pay money, they will throw the mic in the port. Doesn't mean it's legal.

I seen something about mid-west spl comps, and they allowed people to do whatever during a run. Open doors, or windows or whatever. But this wasn't iasca so obviously it doesn't matter. Sorry back on topic, if your competing and doing burps you need to find the resonant frequency of your truck and tune accordingly. Also you could use sound deadening to seal up the cabin, that would help if it's leaking air. Also you need to know what impedence your subs are rising to, so you can wire low enough to get the max rms out of your amp.

Edited November 1, 20168 yr by Billy Jack

the mic was on dash when it did 142db and then 136db with it on dash sealed, when the clamp was done it was done using a burp at 36hz and thats what my system gets its loudest with, the guy has a tool thats used for everyone to place meter on window and ive got a meter thats been calibrated with termlab that dave proulx sells and ive tested before show and was showing same db but wanted to make sure and it was right on with termlab. I have done a ohm test with subs and it shows 2.2ohms. If i take my voltage up to around 14.9v would this maybe help and work on two new batterys and bigger amp alternator. how do i find what subs are rising too? because at rest with subs not being played for hours there at 2.2ohms wired together

hey by the way thank you all for responding and helping me, ive not been online few days so forgive my late response here

 

23 minutes ago, ftj_85 said:

the mic was on dash when it did 142db and then 136db with it on dash sealed, when the clamp was done it was done using a burp at 36hz and thats what my system gets its loudest with, the guy has a tool thats used for everyone to place meter on window and ive got a meter thats been calibrated with termlab that dave proulx sells and ive tested before show and was showing same db but wanted to make sure and it was right on with termlab. I have done a ohm test with subs and it shows 2.2ohms. If i take my voltage up to around 14.9v would this maybe help and work on two new batterys and bigger amp alternator. how do i find what subs are rising too? because at rest with subs not being played for hours there at 2.2ohms wired together

Yes a stronger electrical is always gonna help on a unregularmted amp. And you just need to play your system, and let it warm up and see what your impedence is rising to while your playing a sign wave. Then when you know, you can wire lower to get the max out of your amp. If your wired to 2ohm and it's rising to 4-6ohm then you could wire it down to .5ohm so when it rises, you will still be pretty low around 1-2ohm and see more power. Just don't do it on music, this only works on burps because you can measure your impedence, so you know your not going lower then mtx's recommendation's. On music it will drop way to low, and possibly burn your amp out.  

so have my meter set to ohms and do a since wave of same hz? watch meter while doing this and what volume should i try this at at? and can i do it at the amp or just to the input speaker leads from subs. So just wire it back to normal for music when not doing spl tests.. wish my amp was stable for playing music wired at .5 so i could get more power to them instead of 400rms each ugh need bigger better equipment

Just measure how your gonna play it at comps then you will know what impedence your seeing in the box. And yes just wire to your speaker wires running into your coil. And definetly don't try it on music because music rises and falls and it's impossible to know where it's gonna be. And I definetly wouldn't try .5ohm on music you will fry your amp or drastically shorten its life. My nephew wired his hifonics collosis to .5ohm and it lasted about a week on strong electrical. 

Edited November 3, 20168 yr by Billy Jack

When you measure resistance with your meter that's exactly what you're measuring D.C. resistance. D.C. current resistance is not the same as AC impedance. Impedance changes with the frequency of AC being being applied and depending on the speaker system can rise 3 to 4 times (or more) of the rated impedance or the measured D.C. Resistance. 

If you use ohms law and take the voltage and current that was measured to calculate the power that was applied and calculate the resistance you'll probably find it a fair bit higher than 2.2 ohms. 

10 hours ago, ftj_85 said:

so have my meter set to ohms and do a since wave of same hz? watch meter while doing this and what volume should i try this at at? and can i do it at the amp or just to the input speaker leads from subs. So just wire it back to normal for music when not doing spl tests.. wish my amp was stable for playing music wired at .5 so i could get more power to them instead of 400rms each ugh need bigger better equipment

You need a ammeter and a multimeter to calculate impeadence. You cannot just measure it with a multimeter with power applied to the circuit, it will give you a wrong measurement.