Amp gain settings

 

Bronze Member
Username: Fastshift

Post Number: 22
Registered: Dec-07
Using DMM method, do you simply use 50Hz like people say? wouldn't it depend on what amp?

ive got an alpine MRP-M650 and getting an Alpinr SWR-1222D (Dual 2 Ohn coil just FYI).

O I almost forgot. my amp is rated 400W at 4 Ohm, 600W at 2 Ohm. i don't want to over power my sub so i want the input into my sub to be 500W. would i work if i hook it up at 4 ohm and try to get 500W? could it cause blown amp? or should i hook it up at 1 ohm and get 500W?

so, would 50Hz be ok?
should i hook my sub up at 4 or 1 ohm while my amp is rated at 4 and 2 ohm. well, DUH i don't want to blow my Amp or Sub up.

thank you
 

Gold Member
Username: Nd4spd18

Northwest PA

Post Number: 5106
Registered: Jul-06
That amp is not a good match for that sub, you should have a 1 ohm stable amp. The only thing you can do is wire it to 4 ohms and set your gain for 400w at 4 ohm. Thats the most power you will be able to get.

50 hz test tone will work good.
 

Gold Member
Username: Sinful_systems70

15 INCH WANG...

Post Number: 1079
Registered: Nov-06
50hz 0db tone
 

Gold Member
Username: Jtown

Team Revolution, Texas

Post Number: 1516
Registered: Mar-07
noob question: mV=dc? or ac?
 

Silver Member
Username: Mendonmafia

USA

Post Number: 438
Registered: Aug-06
should have got the dual 4 ohm type r and ran it at 2 ohms to give it 600 rms, it can handle it.

theives, the output of amplifers is always AC and it should be much more than millivolts. not really sure what your asking but hope this helps.
 

Gold Member
Username: Jtown

Team Revolution, Texas

Post Number: 1522
Registered: Mar-07
actually, that didn't help at all.
when reading the DMM, I have a choice of DC or AC voltage, the manual doesn't specify whether mV=DC or AC or ~=DC or AC

I do know that the output of amps is AC, but thank you. Was really wondering how to read my DMM
 

Gold Member
Username: Nd4spd18

Northwest PA

Post Number: 5122
Registered: Jul-06
mV

= millivolts, could be AC or DC



~

= AC voltage



___
- - -

= DC voltage
 

Bronze Member
Username: Fastshift

Post Number: 23
Registered: Dec-07
thanks forthe comments guys.

BTW, M.S., what would happen if i hooke my sub up at 1 ohm? could i blow my amp by doing that? i have no idea.

and i haven't gotten the sub yet. which was good thing i guess. i was planning on getting just one, and then add another sub so i wanted to get double 2 ohm so that way i can supply 300W into each sub (i know its way underpowering) and maybe get different amp or upgrade it to M850.

OR change the whole system lol

thanks again
 

Gold Member
Username: Sinful_systems70

15 INCH WANG...

Post Number: 1093
Registered: Nov-06
NO.... http://www.alpine-usa.com/US-en/products/product.php?model=MRP-M650&lang=en&tab= F ---"Speaker Impedance: 4 or 2 ohm"
 

Silver Member
Username: Mendonmafia

USA

Post Number: 446
Registered: Aug-06
do not hook up that amp to one a ohm load. you will overload your amp. if you plan on getting 2 type R's get a more powerful amp that will do at least 1000rms at either 1 or 2 ohms depending on which coils you go with.

If you get the dual 4 ohm coil model you can run the single sub at 2ohms and if you get an amp that is rated @ 1000watts rms @ 1 ohm it should put down 500 rms @ 2ohms then when you get the second you can run a 1 ohm load and get the 1000rms on both. IMO that is going to be your best bet but will involve you finding an amp that is stable @ 1ohm

If you cant find a 1 ohms stable amp then get an amp that will do 1000rms @ 2ohms and do the same thing described above but get the dual 2ohm and run the one @ 4 ohms and the pair @ 2 ohms.

Btw thoes subs will handle closer to 600 rms as long as its clean power.

i used to run my two 350rms a piece kappa perfects on about 1100 rms every day. however alpine dosnt underrate quite that much but they do a little.
 

Gold Member
Username: Nd4spd18

Northwest PA

Post Number: 5130
Registered: Jul-06
Running a 2 ohm stable amp at 1 ohm will most likely blow the amp
 

Gold Member
Username: Jtown

Team Revolution, Texas

Post Number: 1525
Registered: Mar-07
thanks for clearing it up M.S.
 

Gold Member
Username: Sinful_systems70

15 INCH WANG...

Post Number: 1097
Registered: Nov-06
Your welcome!!!! No problem!!!
 

Silver Member
Username: Marcooo

Post Number: 187
Registered: Mar-07
I was told by Jacob from Sundown to use a 32Hz test tone because my box is tuned to 32Hz. Is that a good way of doing it or is 50Hz just in general better?
 

Bronze Member
Username: Fastshift

Post Number: 29
Registered: Dec-07
another question. am i supposed to have 2 ohm resistor to do this instread of using my sub? some say just disconnect the sub and then set it, and some say have 2 ohm (or 4ohm, what ever ur setting is) resistor connected instead of the sub. im confused...
 

Gold Member
Username: •cam•

BC Canada

Post Number: 1518
Registered: Nov-06
I believe that most meters read AC most accurately at 60 Hz. Something to keep in mind. You would need big resistors built to handle the power your amp can produce. Just do it with the sub disconnected.
 

Gold Member
Username: Jtown

Team Revolution, Texas

Post Number: 1544
Registered: Mar-07
so are you supposed to set the amp with the sub(s) disconnected? I've heard so many mixed answers to that question
 

Gold Member
Username: Nd4spd18

Northwest PA

Post Number: 5175
Registered: Jul-06
Mark:

It should make no difference what frequency test tone you use as long as it's above your amps subsonic filter setting and below the LPF, in other words within the range that the amp will produce. 50 hz is almost always within that range, thats why it's used. If it does make a difference, somethings wrong, i.e. bass boost on, EQ on, etc.



Jinsan:

There's no resistors involved here. There should be nothing but the DMM probes connected to the speaker terminals when setting the gain.
 

Silver Member
Username: Marcooo

Post Number: 189
Registered: Mar-07
I set my gains with bass boost off etc. but I left my eq on i.e. it wasn't flat. Is that a big deal or no?
 

Gold Member
Username: Nd4spd18

Northwest PA

Post Number: 5183
Registered: Jul-06
Yes that means your gain is set wrong. However much your EQ cut or boosted at 50 hz (assuming you used a 50 hz tone), it will be off in relation to that much.
 

Gold Member
Username: Jtown

Team Revolution, Texas

Post Number: 1548
Registered: Mar-07
M.S. set gains with or with out subwoofers connected?
 

Gold Member
Username: Nd4spd18

Northwest PA

Post Number: 5190
Registered: Jul-06
Without
 

Gold Member
Username: Jtown

Team Revolution, Texas

Post Number: 1550
Registered: Mar-07
thanks once again
 

Silver Member
Username: Kickerman

Post Number: 202
Registered: May-06
what is the diffrence between 50hz 0db test tone and a 50hz -3db test tone. i listen to a lot a rap if it helps
 

Gold Member
Username: •cam•

BC Canada

Post Number: 1524
Registered: Nov-06
A -3 dB tone will be half the power.
 

Gold Member
Username: Jtown

Team Revolution, Texas

Post Number: 1555
Registered: Mar-07
the tones off ROE are 0 db, correct?
 

Gold Member
Username: Jtown

Team Revolution, Texas

Post Number: 1556
Registered: Mar-07
"0db, 192kbps, 1:00, 1.41MB"


nevermind
 

Gold Member
Username: Nd4spd18

Northwest PA

Post Number: 5195
Registered: Jul-06
The -Xdb tones are attenuated, think of it as turning the volume down.


Download the WAV format test tones if you can...... not that the difference will be noticeable, I just would use those since they are there.
 

Silver Member
Username: Marcooo

Post Number: 190
Registered: Mar-07
MS, I reset my gains with a flat eq and ended up turning the gain up a little? That's what should have happened since I had 50 Hz turned to +2 before right?
Thanks just checkin
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