I am installing a Kicker KX400.1 in a customer's Volvo on Thursday, and would like to use my fancy new DMM in the procedure.
So far, he has Kenwood H/U that was professionally installed, as well as a pair of my old subs (2 MTX Thunder 4000 10's) and my ratty old amp, I gave it to him because he couldn't afford a different one. The old amp finally gave out, and then we scored this puppy today
Kicker KX400.1
http://tinyurl.com/29rn6o
Just curious as the proper procedure to dial in the 400 watts into a two ohm load. Tell me how to do it, and I will make it so!
Replies (13)
newB on 02/18/2008 22:54:47
not sure what exactly your asking here,
setting the gains via DMM?? so im assuming they are each single 4ohm woofers with a net 2ohm load to the amp?
-Drew
SQLThump on 02/18/2008 23:19:16
Correct. I know a test tone is involved, but little more
swez on 02/19/2008 06:52:28
Here's the formula for converting watts and ohmic to voltage target:
Sq Rt of Watts x Ohms = Voltage
400 x 2 = 800; sq rt of 800 = 28.28 Volts AC = 400 RMS @ 2 ohms
FYI: The DMM automatically reads RMS voltage on the AC voltage scale. A 50-60 Hz test tone is good for dialing in the bass.
Swez
cplkittle on 02/19/2008 15:52:25
Download this spreadsheet, there is an inbedded 60 Hz test tone, move it to the desktop and it will show up as a WMA music file
http://www.datafilehost.com/download.php?file=6d26c621
newB on 02/19/2008 17:24:06
not to thread jack but i have a similar question- when you set the gains on your amp do you set them to the output of the HU or the Ohm load of the woofer??
-Drew
SQLThump on 02/19/2008 18:43:49
Alright, might as well get it out of the way, and state I have failed every math class since the 4th grade, so what exactly is the square root formula?
Need to get this down to effectivly use my new toy. Stupid Math!!!!
ttocs on 02/19/2008 19:37:50
so swez since this is ac we are talkin then is that 28V peak to peak, rms wha????/
I have been installing for almost 15 yrs and only had to grab a signal generator and sillyscope once for a large system with one amp bridged to each speaker. If you want to spend the time with your new toy I understand but I have never understood using a meter to tune your system, what kind of music does it like?
cplkittle on 02/19/2008 21:00:36
Try the spreadsheet I posted above. It is all broken down for you. No math!
bamasaint on 02/20/2008 06:38:15
Download the test tone from the link that kittle used above and burn to CD.
Turn off all audio enhancement on your headunit (ie:loudness,media expander etc.) Null out treble and bass control also.
Turn the gain on the amp all the way down and adjust LPF to 60-70 hz. Null the bass boost.
Set Multi Meter A/C current and select the first voltage past required reading.
Insert test tone CD and set CD player to repeat the track. Place + and - MM leads to the + and - speaker output on the amp.
Increase amp gain until you get a reading of 28.8.
WARNING!!! WILL GET VERY LOUD IN TRUNK!!!
A very good amp should reach max voltage before the amp gain is maxed out with no bass boost.
You will now have to adjust the amp to your taste of music, thats why people rarely use a MM to setup an amp but is a good way to verify mfgs. specs.
Hope that helps.
Mike COFFEE
PS I did this a couple months ago and was a little disapointed.
To reach 400 watts I had to max out amp gain and most of the bassboost.
SQLThump on 02/21/2008 18:27:36
Right on guys, got 'er taken care of. Unfortunatly, can't download anything on my sisters laptop, so I set it according to Swez's word on the voltage.
It took about 3/4's of the gain to acheive this goal, I used Boston Acoustics' "woofer cooker" to dail in the bass. It isn't a test tone, but has lines of insanely deep bass that goes on foor what seem like forever, so it worked fine getting up to the voltage goals.
From there, I put on a few bass dynamic tracks, and dialed in 4-6 (hard to see under the seat.....) Db's of bass boost, which isn't too much considering it goes to 18db's, so aroung 1/4-1/3. It was lacking a little fullness on the rock beats, so I set the crossover to around 80-90hz.
Sounds pretty decent, but not quite the "street shaker" it could be if it was in my car. I personally like dialing in by ear exclusively, but I need this dude's system to be reliable over anything.
Good stuff, pics to come as soon as he emails them....
swez on 02/21/2008 21:45:17
Ttocs, all the meters I have on hand, (Digital and Analog) measure AC voltage in RMS values. If one wanted to experiement at home, set the scale to 150 VAC or higer and probe an electrical outlet in the house. Depending on how good the grid is in a given neighborhood, expect to see a nominal reading of 120 VAC (+/- 5%) here in the USA.
SQL, Calibrated test tones give a more accurate baseline for setting amp gains correctly. Regular music of most any genre will give some degree of accuracy, but are not calibrated. Values on the meter will tend to bump around with the beats and the number readings will often be lower than calibrated test tones. (0 dB is the industry standard for calibrating test gear and amplifiers)
Have also found that in many cases, once the HU is dialed up to about 80% of max values and all tone controls set to flat and no bass boost, amp gains will typically need to be set to below 1.5 volts to reach target output values. This normal for most typical car systems unless one employs a line driver to kick up the RCA signal levels from most HU's on the market today.
Swez
PS No need to be a math wiz for stuff like this. A cheap and dirty calculator will give the square root of any number. Back in the dark ages, (No Calculators in class prior to the mid-70's) we learned how to do this long hand and that was pretty boring and tedious too.
When I hit college level courses in 1974-75, could not afford the HP Scientific notation models some of the rich kids had. (~$350.00 a pop) We used a slide rule. Talk about a real PITA to master!!! No wonder many learned to loathe advanced math and science back then.
cplkittle on 02/23/2008 00:55:10
Swez is trying not to show his age. What he refers to as a slide rule was actually called an abacus.
swez on 02/23/2008 07:41:17
Thank you CplKittle... one more crack like that and you'll be pulling KP duty for a week... LOL
Seriously though, has anyone here ever even seen a slide rule, much less tried to master it's functions in 10 weeks or less?
http://en.wikipedia.org/wiki/Slide_rule
Read the details on multipliction and division and you'll get the picture.
After 1 semester of advanced math and chemistry at a "lightning review" pace, (those who had most of this in HS, but I did not have those classes yet), threw in the towel, quit University life, gave up the scholorship and went back to work. (Skilled Trades Apprentice... Millwright)
Looking back, it was the correct choice. However, failure then was not final. After 3 years of working in a job that had no future, went back to College at a smoother pace. I was very motivated and even when pulling 72 hours per week at work and 16 credits per semester, determination and pure grit resulted in a 4.0 GPA for the initial 6 semesters. (Eventually dropped to 12 credits as the classes were more demanding and still wanted to keep the GPA above 3.6)
OK, this is not intended as a "brag book" accounting. For those in this crowd that are working and going to school as well, the intent is to say we can do whatever we set our minds to and willing to pay the price.
Yes, it's hard to do both well and our personal lives suffer a lot in the process, but the pay off was/is worth the effort. We never know our true capacity for endurance until it has been tested. Those who have served in the military will understand this better than most.
Finally, my cap is off to the guys/gals who put their lives on the line, went into the military and completed their committments with several tours of active war duties. To those who have served or plan to serve at a later time, God bless you all and come home safe and in one piece.
Swez USFLAG
So far, he has Kenwood H/U that was professionally installed, as well as a pair of my old subs (2 MTX Thunder 4000 10's) and my ratty old amp, I gave it to him because he couldn't afford a different one. The old amp finally gave out, and then we scored this puppy today
Kicker KX400.1
http://tinyurl.com/29rn6o
Just curious as the proper procedure to dial in the 400 watts into a two ohm load. Tell me how to do it, and I will make it so!
Replies (13)
newB on 02/18/2008 22:54:47
not sure what exactly your asking here,
setting the gains via DMM?? so im assuming they are each single 4ohm woofers with a net 2ohm load to the amp?
-Drew
SQLThump on 02/18/2008 23:19:16
Correct. I know a test tone is involved, but little more
swez on 02/19/2008 06:52:28
Here's the formula for converting watts and ohmic to voltage target:
Sq Rt of Watts x Ohms = Voltage
400 x 2 = 800; sq rt of 800 = 28.28 Volts AC = 400 RMS @ 2 ohms
FYI: The DMM automatically reads RMS voltage on the AC voltage scale. A 50-60 Hz test tone is good for dialing in the bass.
Swez
cplkittle on 02/19/2008 15:52:25
Download this spreadsheet, there is an inbedded 60 Hz test tone, move it to the desktop and it will show up as a WMA music file
http://www.datafilehost.com/download.php?file=6d26c621
newB on 02/19/2008 17:24:06
not to thread jack but i have a similar question- when you set the gains on your amp do you set them to the output of the HU or the Ohm load of the woofer??
-Drew
SQLThump on 02/19/2008 18:43:49
Alright, might as well get it out of the way, and state I have failed every math class since the 4th grade, so what exactly is the square root formula?
Need to get this down to effectivly use my new toy. Stupid Math!!!!
ttocs on 02/19/2008 19:37:50
so swez since this is ac we are talkin then is that 28V peak to peak, rms wha????/
I have been installing for almost 15 yrs and only had to grab a signal generator and sillyscope once for a large system with one amp bridged to each speaker. If you want to spend the time with your new toy I understand but I have never understood using a meter to tune your system, what kind of music does it like?
cplkittle on 02/19/2008 21:00:36
Try the spreadsheet I posted above. It is all broken down for you. No math!
bamasaint on 02/20/2008 06:38:15
Download the test tone from the link that kittle used above and burn to CD.
Turn off all audio enhancement on your headunit (ie:loudness,media expander etc.) Null out treble and bass control also.
Turn the gain on the amp all the way down and adjust LPF to 60-70 hz. Null the bass boost.
Set Multi Meter A/C current and select the first voltage past required reading.
Insert test tone CD and set CD player to repeat the track. Place + and - MM leads to the + and - speaker output on the amp.
Increase amp gain until you get a reading of 28.8.
WARNING!!! WILL GET VERY LOUD IN TRUNK!!!
A very good amp should reach max voltage before the amp gain is maxed out with no bass boost.
You will now have to adjust the amp to your taste of music, thats why people rarely use a MM to setup an amp but is a good way to verify mfgs. specs.
Hope that helps.
Mike COFFEE
PS I did this a couple months ago and was a little disapointed.
To reach 400 watts I had to max out amp gain and most of the bassboost.
SQLThump on 02/21/2008 18:27:36
Right on guys, got 'er taken care of. Unfortunatly, can't download anything on my sisters laptop, so I set it according to Swez's word on the voltage.
It took about 3/4's of the gain to acheive this goal, I used Boston Acoustics' "woofer cooker" to dail in the bass. It isn't a test tone, but has lines of insanely deep bass that goes on foor what seem like forever, so it worked fine getting up to the voltage goals.
From there, I put on a few bass dynamic tracks, and dialed in 4-6 (hard to see under the seat.....) Db's of bass boost, which isn't too much considering it goes to 18db's, so aroung 1/4-1/3. It was lacking a little fullness on the rock beats, so I set the crossover to around 80-90hz.
Sounds pretty decent, but not quite the "street shaker" it could be if it was in my car. I personally like dialing in by ear exclusively, but I need this dude's system to be reliable over anything.
Good stuff, pics to come as soon as he emails them....
swez on 02/21/2008 21:45:17
Ttocs, all the meters I have on hand, (Digital and Analog) measure AC voltage in RMS values. If one wanted to experiement at home, set the scale to 150 VAC or higer and probe an electrical outlet in the house. Depending on how good the grid is in a given neighborhood, expect to see a nominal reading of 120 VAC (+/- 5%) here in the USA.
SQL, Calibrated test tones give a more accurate baseline for setting amp gains correctly. Regular music of most any genre will give some degree of accuracy, but are not calibrated. Values on the meter will tend to bump around with the beats and the number readings will often be lower than calibrated test tones. (0 dB is the industry standard for calibrating test gear and amplifiers)
Have also found that in many cases, once the HU is dialed up to about 80% of max values and all tone controls set to flat and no bass boost, amp gains will typically need to be set to below 1.5 volts to reach target output values. This normal for most typical car systems unless one employs a line driver to kick up the RCA signal levels from most HU's on the market today.
Swez
PS No need to be a math wiz for stuff like this. A cheap and dirty calculator will give the square root of any number. Back in the dark ages, (No Calculators in class prior to the mid-70's) we learned how to do this long hand and that was pretty boring and tedious too.
When I hit college level courses in 1974-75, could not afford the HP Scientific notation models some of the rich kids had. (~$350.00 a pop) We used a slide rule. Talk about a real PITA to master!!! No wonder many learned to loathe advanced math and science back then.
cplkittle on 02/23/2008 00:55:10
Swez is trying not to show his age. What he refers to as a slide rule was actually called an abacus.
swez on 02/23/2008 07:41:17
Thank you CplKittle... one more crack like that and you'll be pulling KP duty for a week... LOL
Seriously though, has anyone here ever even seen a slide rule, much less tried to master it's functions in 10 weeks or less?
http://en.wikipedia.org/wiki/Slide_rule
Read the details on multipliction and division and you'll get the picture.
After 1 semester of advanced math and chemistry at a "lightning review" pace, (those who had most of this in HS, but I did not have those classes yet), threw in the towel, quit University life, gave up the scholorship and went back to work. (Skilled Trades Apprentice... Millwright)
Looking back, it was the correct choice. However, failure then was not final. After 3 years of working in a job that had no future, went back to College at a smoother pace. I was very motivated and even when pulling 72 hours per week at work and 16 credits per semester, determination and pure grit resulted in a 4.0 GPA for the initial 6 semesters. (Eventually dropped to 12 credits as the classes were more demanding and still wanted to keep the GPA above 3.6)
OK, this is not intended as a "brag book" accounting. For those in this crowd that are working and going to school as well, the intent is to say we can do whatever we set our minds to and willing to pay the price.
Yes, it's hard to do both well and our personal lives suffer a lot in the process, but the pay off was/is worth the effort. We never know our true capacity for endurance until it has been tested. Those who have served in the military will understand this better than most.
Finally, my cap is off to the guys/gals who put their lives on the line, went into the military and completed their committments with several tours of active war duties. To those who have served or plan to serve at a later time, God bless you all and come home safe and in one piece.
Swez USFLAG
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